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   4143篇
  免费   413篇
  国内免费   68篇
医药卫生   4624篇
  2024年   4篇
  2023年   65篇
  2022年   90篇
  2021年   178篇
  2020年   212篇
  2019年   236篇
  2018年   191篇
  2017年   166篇
  2016年   193篇
  2015年   150篇
  2014年   273篇
  2013年   303篇
  2012年   264篇
  2011年   270篇
  2010年   222篇
  2009年   208篇
  2008年   211篇
  2007年   175篇
  2006年   183篇
  2005年   131篇
  2004年   106篇
  2003年   109篇
  2002年   90篇
  2001年   57篇
  2000年   49篇
  1999年   46篇
  1998年   28篇
  1997年   34篇
  1996年   41篇
  1995年   42篇
  1994年   35篇
  1993年   19篇
  1992年   20篇
  1991年   16篇
  1990年   21篇
  1989年   14篇
  1988年   14篇
  1987年   8篇
  1986年   12篇
  1985年   28篇
  1984年   13篇
  1983年   18篇
  1982年   11篇
  1981年   18篇
  1980年   6篇
  1979年   13篇
  1978年   8篇
  1977年   7篇
  1976年   7篇
  1975年   3篇
排序方式: 共有4624条查询结果,搜索用时 15 毫秒
11.
《Clinical neurophysiology》2021,132(1):106-113
ObjectivePoliomyelitis results in changes to the anterior horn cell. The full extent of cortical network changes in the motor physiology of polio survivors has not been established. Our aim was to investigate how focal degeneration of the lower motor neurons (LMN) in infancy/childhood affects motor network connectivity in adult survivors of polio.MethodsSurface electroencephalography (EEG) and electromyography (EMG) were recorded during an isometric pincer grip task in 25 patients and 11 healthy controls. Spectral signal analysis of cortico-muscular (EEG-EMG) coherence (CMC) was used to identify the cortical regions that are functionally synchronous and connected to the periphery during the pincer grip task.ResultsA pattern of CMC was noted in polio survivors that was not present in healthy individuals. Significant CMC in low gamma frequency bands (30–47 Hz) was observed in frontal and parietal regions.ConclusionThese findings imply a differential engagement of cortical networks in polio survivors that extends beyond the motor cortex and suggest a disease-related functional reorganisation of the cortical motor network.SignificanceThis research has implications for other similar LMN conditions, including spinal muscular atrophy (SMA). CMC has potential in future clinical trials as a biomarker of altered function in motor networks in post-polio syndrome, SMA, and other related conditions.  相似文献   
12.
目的:研制一种便携式核事故急救箱,用于核事故现场伤员的自救互救。方法:核事故急救箱外形尺寸为360 mm×240 mm×150 mm,箱体采用5 mm防水板材,表面覆压花铝板,内衬木质纤维板,外层喷涂亚光漆。箱盖内侧设计自带照明装置,箱体内划分为急性放射病防治药放置专区和常规战伤急救药材放置区。急性放射病防治药放置区设计3个Φ50 mm孔洞和4个Φ30 mm孔洞,用于放置配备的抗放药品。结果:用该急救箱在核设施现场开展伤情模拟救治,能满足核事故现场伤员自救互救需求。结论:便携式核事故急救箱设计合理、标识清晰,能有效提高核事故现场伤员自救互救能力和存活率,具有较好的实用价值。  相似文献   
13.
目的:探讨妊娠早期血清学指标糖化血红蛋白(glycohemoglobin,HbA1c)联合妊娠相关血浆蛋白A(pregnancy-associated plasma protein A,PAPP-A)对妊娠期糖尿病(gestational diabetes mellitus,GDM)的预测意义。方法:随机选取2018年12月1日-2019年7月30日孕11~13+6周于我院门诊产检的妊娠妇女,进行临床资料采集并记录妊娠早期(11~13+6周)空腹血糖(fasting plasma glucose,FPG)、HbA1c、PAPP-A中位数倍数(multiple of the median,MoM)水平,根据孕24~28周进行的75 g口服葡萄糖耐量试验(oral glucose tolerance test,OGTT)结果将研究对象分为研究组和对照组,统计分析妊娠早期血清学指标预测GDM的最佳截断值并得出最适宜的联合预测方案。结果:多因素Logistic回归分析显示,高水平FPG和HbA1c、低水平PAPP-A、受孕方式采用辅助生殖技术、有家族糖尿病史以及妊娠早期体质量指数(BMI)为超重或肥胖均是GDM发生的独立危险因素。有糖尿病家族史和使用辅助生殖技术受孕发生GDM的风险显著增高(OR分别为7.206和47.512,均P<0.001)。分析不同预测指标的受试者工作特征(receiver operating characteristic,ROC)曲线及曲线下面积(area under the curve,AUC)显示,PAPP-A MoM联合HbA1c及FPG诊断时AUC最大(0.728),其后依次为PAPPA MoM联合HbA1c(0.721)、HbA1c联合FPG(0.717),均大于HbA1c(0.707)和FPG(0.647),而PAPP-A MoM的AUC为0.380,对GDM没有诊断意义。结论:具有高风险因素的孕妇,推荐在妊娠早期联合检测HbA1c与PAPPA MoM,以早期预测GDM。  相似文献   
14.
目的 利用青少年体重控制行为量表对兰州市高一新生体重控制行为采用状况进行调查,并考察其与学生真实和感知到的体重状态之间的关联,为制定科学的预防和干预方案提供依据。方法 2018年9月在兰州市抽取1 038名高一新生,对其测查青少年体重控制行为量表及感知到体重状态。回收有效数据1 026份,计算健康体重控制行为和不健康体重控制行为的采用率和平均分。结果 参与调查的高一新生中有364名(76.15%)女生和387名(70.62%)男生采用体重控制行为;男女生采用最频繁的两种健康体重控制行为是 “做运动”[男生416例(75.91%),女生318例(66.53%)]和“多吃水果和蔬菜”[(男生412例(75.18%),女生395例(83.51%)];采用最频繁的两种不健康体重控制行为是“减少吃饭的顿数”[(男生93例(16.97%)],女生82例(17.15%)]和“不吃肉”[(男生37例(6.75%),女生77例(16.11%)]。实际超重的男女生比例分别为21.63%和9.79%。与之形成鲜明的对比,高达52.83%的女生自认为超重。自认为超重的被试比自认为不超重的被试更可能采用不健康体重控制行为(χ2=38.94,P<0.01)。结论 兰州地区高一新生体重控制行为的状况非常普遍,这和他们对于体重认知的偏差有关,需从心理层面进行预防和干预。  相似文献   
15.
赵飞 《继续医学教育》2020,34(5):110-112
目的探讨急诊急救护理对有机磷农药中毒患者的效果。方法将2016年3月-2019年3月我院收治的74例有机磷农药中毒患者按随机数字表法分为观察组(n=37)和对照组(n=37)。对照组患者给予常规的急救护理,观察组在对照组的基础上给予高效一体化急救护理。比较两组患者的洗胃时间、洗胃液体容量、胃内容物溢出率以及抢救成功率。结果观察组的洗胃时间、洗胃液体容量、胃内容物溢出率均要明显低于对照组;观察组患者抢救成功率明显高于对照组(P<0.05)。结论对有机磷农药中毒患者应用高效的急诊急救护理,能够明显减少患者的洗胃时间、洗胃液体容量、胃内容物溢出率,提高抢救成功率,值得临床应用。  相似文献   
16.
目的分析大剂量肾上腺素在急性心脏骤停院前急救中的应用价值。方法将2018年1月-2019年10月院前急救处理的52例急性心脏骤停患者视为研究对象,根据其治疗方式划入常规组与大剂量组(n=26)。常规组使用常规剂量肾上腺素与阿托品治疗,大剂量组使用高剂量肾上腺素与阿托品联合治疗,比较患者的治疗效果。结果常规组患者的院前急救复苏成功率是57.69%,大剂量组患者的院前急救复苏成功率是84.62%,且常规组患者的自主循环恢复率、自主呼吸恢复率均低于大剂量组患者,差距比较有统计学意义(P<0.05)。常规组患者治疗后发生8例并发症,大剂量组患者治疗后出现2例并发症(P<0.05)。结论大剂量肾上腺素在急性心脏骤停院前急救中的使用,可提升患者的复苏成功率,恢复患者的自主呼吸、循环能力,降低患者并发症发生率。  相似文献   
17.
The leaves of Rubus suavissimus (also called “Chinese sweet tea”) is used not only as a beverage tea and food additive but also as a folk herbal medicine for the treatment of diabetes mellitus. To systematically investigate its material foundation of efficacy for treating diabetes, herein, a hyphenated strategy by off-line coupling high-speed countercurrent chromatography, ultrafiltration HPLC-UV-MS and prep-HPLC was developed. And thus, α-glucosidase inhibitors from Rubus suavissimus leaves was comprehensively profiled, purified and characterized. As a result, twenty-six compounds were identified as potential α-glucosidase inhibitors and favorably isolated by prep-HPLC. Their structures were identified via UV, MS, and 1H-NMR. Notably, fourteen compounds, including protocatechuic acid (1), myketin (3), epicatechin (4), vanillic acid (6), apigenin (11), catechin (12), ferulic acid (15), luteolin (16), 3, 3′-di-O-methylellagic acid (17), chlorogenic acid (19), 3, 3′-di-O-methylellagic acid-4′-O-β-D-glucoside (20), cinnamic acid (21), syringate (24) and ethylbrevifolin-carboxylate (25), were reported in leaves of Rubus suavissimus for the first time. In addition, α-glucosidase inhibitory activities of compounds 1–26 were evaluated, and eighteen compounds exhibited stronger α-glucosidase inhibitory activities than acarbose (IC50 value at 214.24 ± 3.48 μg/mL, positive control). The results indicated that the proposed method is a highly efficient strategy for comprehensive profiling and purification of bioactive target compounds, including both major and minor components, from natural products.  相似文献   
18.
While some progress has been made in addressing chronic homelessness through supportive models, a comprehensive solution for housing loss must include prevention. The purpose of this article is twofold: to conduct a review of the literature on the domains of the Framework for Homelessness Prevention; and to use literature on the concept of quaternary prevention, preventing the harms of service provision, to theorise an additional domain. The Framework for Homelessness Prevention draws upon theory from public health exploring primary, secondary and tertiary prevention, and also integrates primordial prevention. This leads to a typology of homelessness prevention that incorporates the following five domains: (a) Structural prevention; (b) Systems prevention; (c) Early intervention; (d) Eviction prevention; and (e) Housing stability. By systematically reviewing the literature we build out the evidence‐base supporting these domains. The team used research databases, internet searches and retrospective reference list reviews to identify high‐quality journal articles on prevention, which were then sorted by level of prevention. Through this process, we evolved our thinking on the Framework in considering that quaternary prevention was not initially included. Therefore, we explored the literature related to quaternary prevention in the context of homelessness and offer a sixth domain for the Framework: Empowerment. Ultimately, a comprehensive Framework for Homelessness Prevention will support communities and governments to more effectively prevent homelessness through upstream approaches.  相似文献   
19.
Background and aimsThe purpose of the present study was to investigate the association of gravidity and age at first pregnancy with metabolic syndrome in a large-scale, population-based cohort study in Iran.MethodsThe present secondary analysis was conducted on a subset of the population (5739 women with at least one pregnancy) enrolled in the Tabari cohort study. Reproductive history was collected using a structured questionnaire. The relationship of gravidity and age at first pregnancy with metabolic syndrome and its components was analyzed using the logistic regression model.ResultsThe results showed that after adjustment for confounding variables, the odds of having metabolic syndrome was not significantly associated with age at first pregnancy (P = 0.269) and gravidity (P = 0.504). However, there was an association between hypertension and age at first pregnancy (OR = 0.32, 95% CI = 0.12–0.82; P = 0.03). Additionally, waist circumference was also associated with gravidity (OR = 2.17, 95% CI = 1.37–3.35).ConclusionAs the findings indicated, age at first pregnancy and gravidity were not associated with the odds of having metabolic syndrome. However, a relationship was found between first pregnancy at the age of >35 years and the decreased risk of hypertension. Gravidity was also found to be a dose-dependent risk factor for increased waist circumference.  相似文献   
20.
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