首页 | 本学科首页   官方微博 | 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   9049篇
  免费   2495篇
  国内免费   128篇
耳鼻咽喉   371篇
儿科学   191篇
妇产科学   253篇
基础医学   159篇
口腔科学   208篇
临床医学   2896篇
内科学   1666篇
皮肤病学   309篇
神经病学   690篇
特种医学   328篇
外科学   1284篇
综合类   363篇
现状与发展   2篇
预防医学   1735篇
眼科学   103篇
药学   203篇
  1篇
中国医学   100篇
肿瘤学   810篇
  2024年   80篇
  2023年   410篇
  2022年   116篇
  2021年   255篇
  2020年   488篇
  2019年   167篇
  2018年   561篇
  2017年   601篇
  2016年   618篇
  2015年   709篇
  2014年   706篇
  2013年   1035篇
  2012年   384篇
  2011年   335篇
  2010年   510篇
  2009年   627篇
  2008年   302篇
  2007年   232篇
  2006年   276篇
  2005年   190篇
  2004年   146篇
  2003年   113篇
  2002年   96篇
  2001年   177篇
  2000年   108篇
  1999年   147篇
  1998年   268篇
  1997年   284篇
  1996年   308篇
  1995年   243篇
  1994年   173篇
  1993年   117篇
  1992年   85篇
  1991年   84篇
  1990年   73篇
  1989年   91篇
  1988年   73篇
  1987年   56篇
  1986年   49篇
  1985年   55篇
  1984年   45篇
  1983年   45篇
  1982年   30篇
  1981年   44篇
  1980年   19篇
  1979年   13篇
  1978年   17篇
  1977年   23篇
  1976年   21篇
  1972年   11篇
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
101.
Inhaled beta-agonists can produce bronchodilatation and reduce airway hyperreactivity in patients with asthma. Using these two measures, we compared inhaled bitolterol (three puffs, 1110 micrograms), albuterol (two puffs, 180 micrograms), and placebo administered by metered-dose inhaler in a blinded, crossover study of 40 subjects with chronic asthma. On each study day, subjects underwent histamine challenges at 1 1/2 hours before, and 1/2, 2, 4, 6, and 8 hours after inhaling one of the three test-drug treatments. Both drugs produced significant bronchodilatation at 30 minutes through 4 hours and significant effects on airway reactivity at 30 minutes through 2 hours (p less than 0.05). Bitolterol also produced small but significant bronchodilator effects at 6 hours and effects on airway reactivity at 4 hours (p less than 0.05). Effects of bitolterol on airway reactivity diminished significantly more slowly than effects of albuterol in subjects with baseline provocative concentration causing a 20% fall in FEV1 greater than or equal to 1.0 mg/ml of histamine (half-life of biologic effect 1.37 versus 0.92 hours; p less than 0.05) but not in subjects with baseline provocative concentration causing a 20% fall in FEV1 less than or equal to 1.0 mg/ml (half-life of biologic effect of 1.01 versus 1.00 hours; p greater than 0.05).  相似文献   
102.
目的:观察在蛋白激酶C(PKC)激动剂TPPB促进可溶性淀粉样前体蛋白(sAPPα)释放过程中参与的信号转导通路。方法:以1 μmol/L的TPPB作用于PC12细胞3 h,同时加入信号转导通路的抑制剂,Western印迹法检测上清液内sAPPα的含量和细胞外信号调节激酶(p42/44MAPK)及磷酸化的p42/44MAPK的表达。结果:1 μmol/L的TPPB作用于PC12细胞3 h可以显著增加上清液内sAPPα的含量,细胞外信号调节激酶抑制剂U0126、c-Jun氨基末端激酶抑制剂SP600125和蛋白酪氨酸激酶抑制剂genistein可以部分消除此作用;而p38MAPK抑制剂SB203580对sAPPα的含量无显著影响。1 μmol/L的TPPB可以使磷酸化的p42/44MAPK表达增加,而对总的p42/44MAPK无显著影响。结论:细胞外信号调节激酶、c-Jun氨基末端激酶和蛋白酪氨酸激酶可能参与TPPB促进sAPPα生成的过程。  相似文献   
103.
不同栓塞范围的急性肺栓塞动物模型建立   总被引:2,自引:1,他引:2       下载免费PDF全文
目的:制备不同栓塞范围的急性肺栓塞动物模型,研究血流动力学变化与肺栓塞范围的相关性。方法:经导管注入犬自体血栓选择性栓塞肺动脉,通过控制注入血栓数量、速度,分别建立不同栓塞范围的急性肺栓塞动物模型;比较栓前、栓后15 min、30 min、1 h及2 h血流动力学指标变化,同时观察心脏超声影像学变化。结果:自体血栓均按要求阻塞相应肺动脉,肺栓塞形成后心输出量下降,肺动脉压力及肺毛细血管楔压显著增高,并在0.5 -1 h达到峰值,各血流动力学指标随肺栓塞范围增大而变化更显著。结论:此急性肺栓塞动物模型制作方法确切可行。  相似文献   
104.
105.
106.
107.
108.
109.
Community health and social care practitioners play an increasingly important role in the health promotion agenda, but lack confidence in having effective health behaviour change (HBC) conversations with members of the public. This study reports the development and evaluation of a training intervention based on health psychology to improve health and social care practitioner self-rated confidence, competence and intention to use five behaviour change techniques (BCTs) in their HBC conversations. A 2-day behavioural science interprofessional skills training course plus online learning module was designed for health and social care staff across North East Scotland, teaching five evidence-based BCTs (e.g. Action Planning), plus person-centred communication skills. Participants rated confidence, competence and future intention to use the BCTs on likert scales (1–10) pre-course and post-course, and provided acceptability data. 177 participants aged 20–64 took part, qualitative and quantitative data suggested that the course had high acceptability. Paired samples t tests (n = 120 with complete data) showed significant improvements in confidence, competence and intention following the course, which remained significant with a conservative analysis (n = 174) assuming no change for missing data. Perceived competence in Action Planning increased most during the course (mean change 3.09). In conclusion, health psychology-based skills training can improve practitioner confidence, competence and intention to use evidence-based BCTs; further evaluation is needed to assess practice change.  相似文献   
110.
Cognitive Impairment (CI) screening is recommended for those engaged in harmful levels of alcohol use. However, there is a lack of evidence on implementation. This paper explores the barriers and facilitators to CI screening experienced across a service specifically for older drinkers. The findings draw on data gathered as part of an evaluation of a multilevel programme to reduce alcohol-related harm in adults aged 50 and over in five demonstration areas across the United Kingdom. It is based on qualitative interviews and focus groups with 14 service providers and 22 service users. Findings are presented thematically under the section headings: acceptability of screening, interpretation and making sense of screening and treatment options. It is suggested that engagement with CI screening is most likely when its fit with agency culture and its purpose is clear; where service providers have the technical skills to administer and discuss the results of screening with service users; and where those undertaking screening have had the opportunity to reflect on their own experience of being screened. Engagement with CI screening is also most likely where specific intervention pathways and engagement practices can be accessed to respond to assessed need.  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