首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   14288篇
  免费   1013篇
  国内免费   90篇
医药卫生   15391篇
  2024年   18篇
  2023年   188篇
  2022年   196篇
  2021年   940篇
  2020年   532篇
  2019年   655篇
  2018年   660篇
  2017年   452篇
  2016年   485篇
  2015年   533篇
  2014年   638篇
  2013年   771篇
  2012年   1291篇
  2011年   1153篇
  2010年   585篇
  2009年   514篇
  2008年   785篇
  2007年   760篇
  2006年   693篇
  2005年   673篇
  2004年   528篇
  2003年   505篇
  2002年   309篇
  2001年   196篇
  2000年   169篇
  1999年   151篇
  1998年   67篇
  1997年   49篇
  1996年   53篇
  1995年   37篇
  1994年   22篇
  1993年   40篇
  1992年   86篇
  1991年   72篇
  1990年   47篇
  1989年   60篇
  1988年   44篇
  1987年   34篇
  1986年   41篇
  1985年   45篇
  1984年   35篇
  1983年   25篇
  1982年   21篇
  1981年   21篇
  1979年   24篇
  1978年   18篇
  1975年   22篇
  1973年   18篇
  1972年   18篇
  1970年   15篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
101.
BackgroundHyderabad, Pakistan, was the first city to witness an outbreak of extensively drug resistant (XDR) typhoid fever. The outbreak strain is resistant to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, fluoroquinolones, and third-generation cephalosporin, thus greatly limiting treatment options. However, despite over 5000 documented cases, information on mortality and morbidity has been limited.ObjectiveTo address the existing knowledge gap, this study aimed to assess the morbidity and mortality associated with XDR and non-XDR Salmonella serovar Typhi infections in Pakistan.MethodsWe reviewed the medical records of culture-confirmed typhoid cases in 5 hospitals in Hyderabad from October 1, 2016, to September 30, 2018. We recorded data on age, gender, onset of fever, physical examination, serological and microbiological test results, treatment before and during hospitalization, duration of hospitalization, complications, and deaths.ResultsA total of 1452 culture-confirmed typhoid cases, including 947 (66%) XDR typhoid cases and 505 (34%) non-XDR typhoid cases, were identified. Overall, ≥1 complications were reported in 360 (38%) patients with XDR typhoid and 89 (18%) patients with non-XDR typhoid (P<.001). Ileal perforation was the most commonly reported complication in both patients with XDR typhoid (n=210, 23%) and patients with non-XDR typhoid (n=71, 14%) (P<.001). Overall, mortality was documented among 17 (1.8%) patients with XDR S Typhi infections and 3 (0.6%) patients with non-XDR S Typhi infections (P=.06).ConclusionsAs this first XDR typhoid outbreak continues to spread, the increased duration of illness before hospitalization and increased rate of complications have important implications for clinical care and medical costs and heighten the importance of prevention and control measures.  相似文献   
102.
ObjectivesLittle is known about emergency department (ED) utilization among the nearly 1 million older adults residing in assisted living (AL) settings. Unlike federally regulated nursing homes, states create and enforce AL regulations with great variability, which may affect the quality of care provided. The objective of this study was to examine state variability in all-cause and injury-related ED use among residents in AL.DesignObservational retrospective cohort study.Setting and ParticipantsWe identified a cohort of 293,336 traditional Medicare beneficiaries residing in larger AL communities (25+ beds).MethodsWith Medicare enrollment and claims data, we identified ED visits and classified those because of injury. We present rates of all-cause and injury-related ED use per 100 person-years in AL, by state, adjusting for age, sex, race, dual-eligibility, and chronic conditions.ResultsRisk-adjusted state rates of all-cause ED visits ranged from 100.9 visits/100 AL person-years [95% confidence interval (CI) 92.8, 109.9] in New Mexico to 162.3 visits/100 AL person-years (95% CI 154.0, 174.7) in Rhode Island. The risk-adjusted rate of injury-related ED visits ranged from 18.7 visits/100 AL person-years (95% CI 17.2, 20.3) in New Mexico to 35.7 visits/100 AL person-years (95% CI 34.7, 36.8) in North Carolina.Conclusions and ImplicationsWe observed significant variability among states in all-cause and injury-related ED use among AL residents. There is an urgent need to better understand why this variability is occurring to prevent avoidable visits to the ED.  相似文献   
103.
104.
105.
In April 2017, surveillance detected a surge in severe acute respiratory infections (SARI) in Bangladesh. We collected specimens from SARI patients and asymptomatic controls for analysis with multipathogen diagnostic tests. Influenza A(H1N1)pdm09 was associated with the SARI epidemic, suggesting that introducing vaccines and empiric antiviral drugs could be beneficial.  相似文献   
106.
International Urology and Nephrology - We aimed to determine the potential relationship between atherosclerotic cardiovascular disease (ASCVD) score, which equates to 10-year risk of...  相似文献   
107.
This study reports the first evaluation of sperm hyaluronan binding assay (HBA) for predicting the fertility of Nili-Ravi buffalo bulls in relation to standard parameters of sperm quality. Cryopreserved semen doses of low (n = 6), medium (n = 3) and high fertility (n = 8) bulls based on their respective return rates were used. Significantly, more spermatozoa bound to hyaluronan from the most fertile bulls (57.15% ± 1.44) compared with medium (42.46% ± 1.08) and low fertility bulls (29.70% ± 0.78). A strongly positive correlation (r = .824, p < .01) was found between HBA and fertility that predicts a 67.9% variability (r2 = .679, p < .01) in fertility. HBA was also strongly positively correlated with sperm viability (r = .679, p < .01) followed by their live/dead ratio (r = .637, p < .01), uncapacitated spermatozoa (r = .631, p < .01), normal apical ridge (r = .459, p < .01), motility (r = .434, p < .01), mature spermatozoa with low residual histones (r = .364, p < .01), high plasma membrane integrity (r = .316, p < .01) and nonfragmented DNA levels (r = .236, p < .05). It was negatively correlated with spermatozoa having reacted acrosome (r = −.654, p < .01). A fertility model built using a combination of sperm HBA and either sperm livability or viability predicts, respectively, 86.1% (r2 = .861, p < .01) and 85.9% (r2 = .859, p < .01) variability in buffalo bull fertility. In conclusion, sperm HBA may prove to be a single robust predictor of Nili-Ravi buffalo bull fertility.  相似文献   
108.
Neurosurgical Review - The pathogenesis and natural history of intracranial aneurysm (IA) remains poorly understood. To this end, animal models with induced cerebral vessel lesions mimicking human...  相似文献   
109.
BackgroundA diverse physician workforce improves the quality of care for all patients, and there is a need for greater diversity in orthopaedic surgery. It is important that medical students of diverse backgrounds be encouraged to pursue the specialty, but to do so, we must understand students’ perceptions of diversity and inclusion in orthopaedics. We also currently lack knowledge about how participation in an orthopaedic clinical rotation might influence these perceptions.Questions/purposes(1) How do the perceptions of diversity and inclusion in orthopaedic surgery compare among medical students of different gender identities, races or ethnicities, and sexual orientations? (2) How do perceptions change after an orthopaedic clinical rotation among members of demographic groups who are not the majority in orthopaedics (that is, cis-gender women, underrepresented racial minorities, other racial minorities, and nonheterosexual people)?MethodsWe surveyed students from 27 US medical schools who had completed orthopaedic rotations. We asked about their demographic characteristics, rotation experience, perceptions of diversity and inclusion in orthopaedics, and personal views on specialty choice. Questions were derived from diversity, equity, and inclusion climate surveys used at major academic institutions. Cis-gender men and cis-gender women were defined as those who self-identified their gender as men or women, respectively, and were not transgender. Forty-five percent (59 of 131) of respondents were cis-men and 53% (70 of 131) were cis-women; 49% (64 of 131) were white, 20% (26 of 131) were of underrepresented racial minorities, and 31% (41 of 131) were of other races. Eighty-five percent (112 of 131) of respondents were heterosexual and 15% (19 of 131) reported having another sexual orientation. We compared prerotation and postrotation perceptions of diversity and inclusion between majority and nonmajority demographic groups for each demographic domain (for example, cis-men versus cis-women). We also compared prerotation to postrotation perceptions within each nonmajority demographic group. To identify potential confounding variables, we performed univariate analysis to compare student and rotation characteristics across the demographic groups, assessed using an alpha of 0.05. No potential confounders were identified. Statistical significance was assessed at a Bonferroni-adjusted alpha of 0.0125. Our estimated response percentage was 26%. To determine limitations of nonresponse bias, we compared all early versus late responders and found that for three survey questions, late responders had a more favorable perception of diversity in orthopaedic surgery, whereas for most questions, there was no difference.ResultsBefore rotation, cis-women had lower agreement that diversity and inclusion are part of orthopaedic culture (mean score 0.96 ± 0.75) compared with cis-men (1.4 ± 1.1) (mean difference 0.48 [95% confidence interval 0.16 to 0.81]; p = 0.004), viewed orthopaedic surgery as less diverse (cis-women 0.71 ± 0.73 versus cis-men 1.2 ± 0.92; mean difference 0.49 [95% CI 0.20 to 0.78]; p = 0.001) and more sexist (cis-women 1.3 ± 0.92 versus cis-men 1.9 ± 1.2; mean difference 0.61 [95% CI 0.23 to 0.99]; p = 0.002), believed they would have to work harder than others to be valued equally (cis-women 2.8 ± 1.0 versus cis-men 1.9 ± 1.3; mean difference 0.87 [95% CI 0.45 to 1.3]; p < 0.001), and were less likely to pursue orthopaedic surgery (cis-women 1.4 ± 1.4 versus cis-men 2.6 ± 1.1; mean difference 1.2 [95% CI 0.76 to 1.6]; p < 0.001). Before rotation, underrepresented minorities had less agreement that diversity and inclusion are part of orthopaedic surgery culture (0.73 ± 0.72) compared with white students (1.5 ± 0.97) (mean difference 0.72 [95% CI 0.35 to 1.1]; p < 0.001). Many of these differences between nonmajority and majority demographic groups ceased to exist after rotation. Compared with their own prerotation beliefs, after rotation, cis-women believed more that diversity and inclusion are part of orthopaedic surgery culture (prerotation mean score 0.96 ± 0.75 versus postrotation mean score 1.2 ± 0.96; mean difference 0.60 [95% CI 0.22 to 0.98]; p = 0.002) and that orthopaedic surgery is friendlier (prerotation 2.3 ± 1.2 versus postrotation 2.6 ± 1.1; mean difference 0.41 [95% CI 0.14 to 0.69]; p = 0.004), more diverse (prerotation 0.71 ± 0.73 versus postrotation 1.0 ± 0.89; mean difference 0.28 [95% CI 0.08 to 0.49]; p = 0.007), less sexist (prerotation 1.3 ± 0.92 versus postrotation 1.9 ± 1.0; mean difference 0.63 [95% CI 0.40 to 0.85]; p < 0.001), less homophobic (prerotation 2.1 ± 1.0 versus postrotation 2.4 ± 0.97; mean difference 0.27 [95% CI 0.062 to 0.47]; p = 0.011), and less racist (prerotation 2.3 ± 1.1 versus postrotation 2.5 ± 1.1; mean difference 0.28 [95% CI 0.099 to 0.47]; p = 0.003). Compared with before rotation, after rotation cis-women believed less that they would have to work harder than others to be valued equally on the rotation (prerotation 2.8 ± 1.0 versus postrotation 2.5 ± 1.0; mean difference 0.31 [95% CI 0.12 to 0.50]; p = 0.002), as did nonheterosexual students (prerotation 2.4 ± 1.4 versus postrotation 1.8 ± 1.3; mean difference 0.56 [95% 0.21 to 0.91]; p = 0.004). Underrepresented minority students saw orthopaedic surgery as less sexist after rotation compared with before rotation (prerotation 1.5 ± 1.1 versus postrotation 2.0 ± 1.1; mean difference 0.52 [95% CI 0.16 to 0.89]; p = 0.007).ConclusionEven with an estimated 26% response percentage, we found that medical students of demographic backgrounds who are not the majority in orthopaedics generally perceived that orthopaedic surgery is less diverse and inclusive than do their counterparts in majority groups, but these views often change after a clinical orthopaedic rotation.Clinical RelevanceThese perceptions may be a barrier to diversification of the pool of medical student applicants to orthopaedics. However, participation in an orthopaedic surgery rotation is associated with mitigation of many of these negative perceptions among diverse students. Medical schools have a responsibility to develop a diverse workforce, and given our findings, schools should promote participation in a clinical orthopaedic rotation. Residency programs and orthopaedic organizations can also increase exposure to the field through the rotation and other means. Doing so may ultimately diversify the orthopaedic surgeon workforce and improve care for all orthopaedic patients.  相似文献   
110.
With the development of insulin resistance (IR), there is a compensatory increase in the plasma insulin response to offset the defect in insulin action to maintain normal glucose tolerance. The insulin response is the result of two factors: insulin secretion and metabolic clearance rate of insulin (MCRI). Subjects (104 with normal glucose tolerance [NGT], 57 with impaired glucose tolerance [IGT], and 207 with type 2 diabetes mellitus [T2DM]), divided in nonobese and obese groups, received a euglycemic insulin-clamp (40 mU/m2 ⋅ min) and an oral glucose tolerance test (OGTT) (75 g) on separate days. MCRI was calculated during the insulin-clamp performed with [3-3H]glucose and the OGTT and related to IR: peripheral (glucose uptake during the insulin clamp), hepatic (basal endogenous glucose production × fasting plasma insulin [FPI]), and adipocyte (fasting free fatty acid × FPI). MCRI during the insulin clamp was reduced in obese versus nonobese NGT (0.60 ± 0.03 vs. 0.73 ± 0.02 L/min ⋅ m2, P < 0.001), in nonobese IGT (0.62 ± 0.02, P < 0.004), and in nonobese T2DM (0.68 ± 0.02, P < 0.03). The MCRI during the insulin clamp was strongly and inversely correlated with IR (r = −0.52, P < 0.0001). During the OGTT, the MCRI was suppressed within 15–30 min in NGT and IGT subjects and remained suppressed. In contrast, suppression was minimal in T2DM. In conclusion, the development of IR in obese subjects is associated with a decline in MCRI that represents a compensatory response to maintain normal glucose tolerance but is impaired in individuals with T2DM.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号