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   2654952篇
  免费   242425篇
  国内免费   12534篇
医药卫生   2909911篇
  2021年   49842篇
  2020年   34681篇
  2019年   57557篇
  2018年   69493篇
  2017年   52458篇
  2016年   57830篇
  2015年   72412篇
  2014年   106525篇
  2013年   171528篇
  2012年   71764篇
  2011年   68761篇
  2010年   111160篇
  2009年   117108篇
  2008年   56238篇
  2007年   56694篇
  2006年   68360篇
  2005年   64092篇
  2004年   66526篇
  2003年   57891篇
  2002年   47890篇
  2001年   63936篇
  2000年   54311篇
  1999年   61022篇
  1998年   54958篇
  1997年   53913篇
  1996年   51480篇
  1995年   52343篇
  1994年   46683篇
  1993年   43689篇
  1992年   41051篇
  1991年   39224篇
  1990年   36478篇
  1989年   36754篇
  1988年   34119篇
  1987年   33268篇
  1986年   31701篇
  1985年   32907篇
  1984年   34051篇
  1983年   32327篇
  1982年   36345篇
  1981年   34673篇
  1980年   32718篇
  1979年   26278篇
  1978年   26434篇
  1977年   24938篇
  1976年   22676篇
  1975年   20685篇
  1974年   19775篇
  1973年   19106篇
  1972年   18047篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Abstract

Objectives: This study examined word use as an indicator of interpersonal positive reframing in daily conversations of couples coping with breast cancer and as a predictor of stress.

Design: The Electronically Activated Recorder (EAR) and Linguistic Inquiry and Word Count (LIWC) were used to examine naturally occurring word use conceptually linked to positive reframing (positive emotion, negative emotion, and cognitive processing words).

Sample: Fifty-two couples coping with breast cancer.

Methods: Couples wore the EAR, a device participants wear, that audio-recorded over one weekend (>16,000 sound files), and completed self-reports of positive reframing (COPE) and stress (Perceived Stress Scale). LIWC, a software program, measured word use.

Findings: Both partners’ word use (i.e., positive emotion and cognitive processing words) was associated with their own reported positive reframing, and spouses’ word use was also indicative of patients’ positive reframing. Results also revealed that, in general, words indicating positive reframing predicted lower levels of stress.

Conclusions: Findings supported the hypothesis that partners—and particularly spouses of breast cancer patients—may assist each other’s coping by positively reframing the cancer experience and other negative experiences in conversation.  相似文献   
992.
993.

Purpose

A hydrogel rectal spacer (HRS) is a medical device that is approved by the U.S. Food and Drug Administration to increase the separation between the prostate and rectum. We conducted a cost-effectiveness analysis of HRS use for reduction in radiation therapy (RT) toxicities in patients with prostate cancer (PC) undergoing external beam RT (EBRT).

Methods and Materials

A multistate Markov model was constructed from the U.S. payer perspective to examine the cost-effectiveness of HRS in men with localized PC receiving EBRT (EBRT alone vs EBRT + HRS). The subgroups analyzed included site of HRS placement (hospital outpatient, physician office, ambulatory surgery center) and proportion of patients with good baseline erectile function (EF). Data on EF, gastrointestinal and genitourinary toxicities incidence, and potential risks associated with HRS implantation were obtained from a recently published randomized clinical trial. Health utilities and costs were derived from the literature and the 2018 Physician Fee Schedule and were discounted 3% annually. Quality-adjusted life years (QALYs) and costs were modeled for a 5-year period from receipt of RT. Probabilistic sensitivity analysis and value-based threshold analyses were conducted.

Results

The per-patient 5-year incremental cost for spacers administered in a hospital outpatient setting was $3578, and the incremental effectiveness was 0.0371 QALYs. The incremental cost-effectiveness ratio was $96,440/QALY for patients with PC undergoing HRS insertion in a hospital and $39,286/QALY for patients undergoing HRS insertion in an ambulatory facility. For men with good baseline EF, the incremental cost-effectiveness ratio was $35,548/QALY and $9627/QALY in hospital outpatient and ambulatory facility settings, respectively.

Conclusions

Based on the current Medicare Physician Fee Schedule, HRS is cost-effective at a willingness to pay threshold of $100,000. These results contain substantial uncertainty, suggesting more evidence is needed to refine future decision-making.  相似文献   
994.
995.
996.

Background

Pregnant women are at increased risk of hospitalization, serious complications, poor pregnancy outcomes, and mortality from influenza. Prior research suggests that there are racial/ethnic disparities in vaccination coverage and that a healthcare provider vaccination recommendation is associated with significantly higher vaccine uptake than without such a recommendation. The purpose of this study is to examine racial/ethnic disparities in healthcare providers’ recommendations for pregnant women to receive the influenza vaccine and in vaccine uptake.

Methods

This cross-sectional population-based study analyzed data from the Centers for Disease Control and Prevention’s Pregnancy Risk Assessment Monitoring System (PRAMS) during 2012–2015 (n?=?130161). Both healthcare provider recommendation and vaccine uptake were assessed dichotomously. Logistic regression was conducted to ascertain adjusted odds ratios and 95% confidence intervals, controlling for maternal age, marital status, education, prenatal care utilization, and smoking status.

Results

Influenza vaccine uptake during pregnancy ranged from 39.1% among non-Hispanic (NH) Black women to 55.4% among NH Asian women. In the adjusted analysis, NH Black and NH Asian women had 19% (95% CI 0.75–0.86) and 34% (95% CI 0.61–0.72) decreased odds of receiving a provider recommendation for influenza vaccine during pregnancy, respectively, compared to NH White women. For influenza vaccine uptake, NH Black women were 30% less likely (95% CI 0.65–0.74) to receive influenza vaccine during pregnancy compared to NH White women.

Conclusions

Our findings indicate that there are racial/ethnic disparities in healthcare provider recommendation and influenza vaccine uptake among pregnant women in the United States. Targeted efforts toward providers and interventions focusing on pregnant women may be warranted to reduce the disparity.  相似文献   
997.

Background

The ZOE-50 (NCT01165177) and ZOE-70 (NCT01165229) phase 3 clinical trials showed that the adjuvanted recombinant zoster vaccine (RZV) was ≥90% efficacious in preventing herpes zoster in adults. Here we present a comprehensive overview of the safety data from these studies.

Methods

Adults aged ≥50 (ZOE-50) and ≥70 (ZOE-70) years were randomly vaccinated with RZV or placebo. Safety analyses were performed on the pooled total vaccinated cohort, consisting of participants receiving at least one dose of RZV or placebo. Solicited and unsolicited adverse events (AEs) were collected for 7 and 30?days after each vaccination, respectively. Serious AEs (SAEs) were collected from the first vaccination until 12?months post-last dose. Fatal AEs, vaccination-related SAEs, and potential immune-mediated diseases (pIMDs) were collected during the entire study period.

Results

Safety was evaluated in 14,645 RZV and 14,660 placebo recipients. More RZV than placebo recipients reported unsolicited AEs (50.5% versus 32.0%); the difference was driven by transient injection site and solicited systemic reactions that were generally seen in the first week post-vaccination. The occurrence of overall SAEs (RZV: 10.1%; Placebo: 10.4%), fatal AEs (RZV: 4.3%; Placebo: 4.6%), and pIMDs (RZV: 1.2%; Placebo: 1.4%) was balanced between groups. The occurrence of possible exacerbations of pIMDs was rare and similar between groups. Overall, except for the expected local and systemic symptoms, the safety results were comparable between the RZV and Placebo groups irrespective of participant age, gender, or race.

Conclusions

No safety concerns arose, supporting the favorable benefit-risk profile of RZV.  相似文献   
998.

Background

There were increased reports of fevers and febrile reactions in young children (particularly children aged <5?years) receiving the Seqirus/CSL Southern Hemisphere 2010 trivalent inactivated influenza vaccine (IIV3). Modifying the vaccine manufacturing process by increasing the minimum concentration of splitting agent (sodium taurodeoxycholate [TDOC]) from 0.5% w/v to 1.5% w/v for all strains resolved this issue. The current analysis compared fever rates in three pediatric studies of Seqirus IIV3 (S-IIV3) or quadrivalent inactivated influenza vaccine (S-IIV4), prepared using the modified manufacturing process, with fever rates in three pediatric studies of historical (pre-2010) IIV3 formulations. The historical IIV3 formulations, S-IIV3, and S-IIV4 had 0/3, 2/3, and 4/4 vaccine strains split at 1.5% TDOC, respectively.

Methods

For each study, fever rates (any grade and severe) were determined for the following age subgroups (as applicable), using the fever intensity grading system used in the S-IIV3/S-IIV4 studies: 6?months to <3?years; 3 to <5?years; 5 to <9?years; and 9 to <18?years.

Results

For each age subgroup, the any grade and severe fever rates were lower in the S-IIV3/S-IIV4 studies than in the historical IIV3 formulation studies, with the greatest differences in fever rates observed in the youngest age groups. In the 6?months to <3?years group, the any grade fever rate was 7.0% (severe fever: 2.5%) in one S-IIV4 study compared with 38.7% to 40.0% (severe fever: 9.6% to 17.8%) in the historical IIV3 formulation studies. In the 3 to <5?years subgroup, the any grade fever rate was 4.9% (severe fever: 1.2%) in one S-IIV4 study compared with 34.1% to 36.0% (severe fever: 6.3% to 16.5%) in the historical IIV3 formulation studies.

Conclusion

This analysis provides clinical evidence that the modified manufacturing process improved the fever profile across all pediatric age groups, in particular, in children aged <5?years.  相似文献   
999.

Background

Observational studies of the relative effectiveness of influenza vaccines are essential for public health decision making. Their estimates, however, are subject to bias due to unmeasured confounders. Instrumental variable (IV) methods can control for observed and unobserved confounders.

Methods

We used linked electronic medical record databases in the Veterans Health Administration (VHA) as well as Medicare administrative files to examine the relative vaccine effectiveness (rVE) of high-dose influenza vaccine (HD) versus standard-dose influenza vaccines (SD) in preventing hospitalizations among VHA-enrolled Veterans ≥65?years of age during 5 influenza seasons (2010–2011 through 2014–2015). Using multivariable IV Poisson regression modeling to address unmeasured confounding and bias, we analyzed the data by each season and through longitudinal analysis of all five seasons.

Findings

We included 3,638,924 person–influenza seasons of observation where 158,636 (4%) were among HD vaccine recipients and 3,480,288 (96%) were among SD vaccine recipients. Of the 1,728,562 Veterans, 1,702,824 (98.5%) were male and 1,299,412 (75%) were non-Hispanic white. Based on the longitudinal analysis of all five seasons, the IV-adjusted rVE estimate of HD vs. SD was 10% (95% CI, 8–12%) against all-cause hospitalization; 18% (95% CI, 15–21%) against cardiorespiratory-associated hospitalization; and 14% (95% CI, 6–22%) against influenza/pneumonia-associated hospitalization. The findings by season were similar.

Interpretation

Our analysis of VHA clinical data collected from approximately 1.7 million Veterans 65?years and older during five seasons demonstrates that high-dose influenza vaccine is more effective than standard-dose influenza vaccines in preventing influenza- or pneumonia-associated hospitalizations, cardiorespiratory hospitalizations, and all-cause hospitalizations.  相似文献   
1000.

Introduction

Invasive meningococcal disease (IMD) is a severe disease mainly affecting infants and young children. The most common serogroup causing IMD in Germany is the serogroup type B Neisseria meningitidis (MenB). The aim of the present study is to estimate the economic burden of MenB-related IMD in Germany.

Method

A bottom-up, model-based costing approach has been used to calculate the diagnose- and age-specific yearly lifetime costs of a hypothetical cohort of MenB-related IMD cases. Direct costs contain the treatment cost for the acute phase of the disease, long-term sequelae, costs for rehabilitation, and public health response. Indirect costs are calculated for the human-capital approach and the friction-cost approach considering productivity losses of patients or parents for the acute phase and long-term sequelae. Publicly available databases from the Federal Statistical Office, the SOEP panel data set, literature, and expert opinion were used as data sources. All future costs beyond the reference year of 2015 were discounted at 3%.

Results

The total costs for the hypothetical cohort (343 patients) from a societal perspective are €19.6 million (€57,100/IMD case) using the friction-cost approach and €58.8 million (€171,000/IMD case) using the human-capital approach. Direct costs amount to €18.6 million or €54,300 €/case. Sequelae are responsible for 81% of the direct costs/case.

Discussion

The elevated costs/MenB-related IMD case reflect the severity of the disease. The total costs are sensitive to the productivity-loss estimation approach applied. MenB is an uncommon but severe disease; The costs/case reflect the severity of the disease and is within the same magnitude as for human papilloma virus infections. The available literature on sequelae is due to the uncommonness limited and heterogeneous.  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