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   137862篇
  免费   9616篇
  国内免费   630篇
耳鼻咽喉   1671篇
儿科学   3469篇
妇产科学   2520篇
基础医学   17591篇
口腔科学   2912篇
临床医学   13594篇
内科学   28374篇
皮肤病学   1771篇
神经病学   12123篇
特种医学   5508篇
外科学   22105篇
综合类   1991篇
现状与发展   1篇
一般理论   174篇
预防医学   12559篇
眼科学   2934篇
药学   9730篇
  2篇
中国医学   179篇
肿瘤学   8900篇
  2023年   678篇
  2022年   1057篇
  2021年   2599篇
  2020年   1481篇
  2019年   2416篇
  2018年   2951篇
  2017年   2139篇
  2016年   2251篇
  2015年   2746篇
  2014年   4060篇
  2013年   6119篇
  2012年   8945篇
  2011年   9526篇
  2010年   5302篇
  2009年   4854篇
  2008年   8473篇
  2007年   9071篇
  2006年   8632篇
  2005年   8798篇
  2004年   8459篇
  2003年   7961篇
  2002年   7761篇
  2001年   1325篇
  2000年   1099篇
  1999年   1438篇
  1998年   1646篇
  1997年   1318篇
  1996年   1269篇
  1995年   1245篇
  1994年   1042篇
  1993年   1015篇
  1992年   885篇
  1991年   905篇
  1990年   799篇
  1989年   776篇
  1988年   786篇
  1987年   774篇
  1986年   787篇
  1985年   869篇
  1984年   947篇
  1983年   881篇
  1982年   1150篇
  1981年   1172篇
  1980年   976篇
  1979年   652篇
  1978年   689篇
  1977年   613篇
  1976年   534篇
  1975年   480篇
  1974年   492篇
排序方式: 共有10000条查询结果,搜索用时 34 毫秒
91.
The hairline and frontal hair volume are frequently overlooked aspects of attractive facial proportion and overall facial aesthetics. The author contends that patient benefit from hair restoration surgery is significant, and these procedures should be routinely considered as part of a complete facial rejuvenation.  相似文献   
92.
93.
Health education campaigns which utilise the mass media generally employ advertising techniques. Television and print media are considered more influential, with radio being primarily used for awareness raising and campaign support messages. There is relatively little research into the effectiveness of radio talkback programs in promoting health or reducing illness. This paper argues a case for health and welfare professionals to utilise talkback radio as part of their health promotion activities.  相似文献   
94.
An endogenous ouabain-like substance (OLS) plays a critical role in the etiology of experimental models of human hypertension induced by a high salt diet. Early on, evidence for a role of this Na, K-ATPase inhibitor in blood pressure regulation was provided mainly by correlations of blood pressure with the levels of circulating Na, K-ATPase inhibitor. However, over the past decade, numerous studies have shown that endogenous Na pump inhibitors in the brain mediate salt-dependent hypertension in a variety of experimental models, including Dahl salt-sensitive (Dahl-S) and spontaneously hypertensive (SHR) rats on a high-salt diet. Other forms of hypertension that are known to be mediated by endogenous ouabain-like substances include steroid/salt- (e.g., DOCA-salt) and ACTH-induced hypertension. Even when exogenous ouabain is peripherally administered and/or the plasma ouabain/OLS level is increased in rats, the resulting hypertension is of CNS origin. After peripheral ouabain administration, ouabain levels increase in the plasma and the inhibitor subsequently accumulates in the brain. The ensuing hypertension is abolished by the intracerebroventricular (icv) administration of an anti-ouabain antibody (but not by the same antibody dose given iv), by discrete excitotoxic lesions in the brain or by ganglionic blockade, demonstrating that the response is neurally mediated. The pressor response to stimuli that increase the brain OLS (high salt diet, icv sodium) or to icv ouabain is abolished by icv losartan, demonstrating that the brain OLS activates the brain renin-angiotensin system (RAS) downstream. There are three isoforms of the catalytic alpha subunit of the Na, K-ATPase in the brain and cardiovascular system (alpha1, alpha2 and alpha3), but it is not known which brain isoform(s) mediate the hypertensive effects of circulating/CNS ouabain. Preliminary studies in gene-targeted mice suggest that the alpha2 isoform plays a critical role.  相似文献   
95.
96.
97.
98.
99.
100.
PURPOSE: To determine if deliberate hypotension decreases blood loss and transfusion requirements in patients undergoing orthopedic surgery, a systematic review of all randomized trials addressing this issue was undertaken. METHODS: Electronic databases, citations lists and review articles were searched for potential articles. Relevant articles met the following inclusion criteria: English language, humans undergoing orthopedic surgery, deliberate hypotension used by any method, intraoperative blood loss measured as an outcome, and the trial methodology being randomized and controlled. Four outcomes were analyzed, including estimated blood loss, blood transfused, surgery duration, and quality of the surgical field. For all analyses, the random-effects model was used. RESULTS: Seventeen articles met the inclusion criteria. The surgeries studied included total hip arthroplasty (seven), orthognathic surgery (eight), total knee arthroplasty (one) and spinal fusion (one). A total of 636 patients were randomized across all studies. For blood loss, the overall weighted mean difference favoured treatment, with a savings of about 287 mL of blood [95% confidence interval (CI): -447, -127]. The mean differences also showed a statistically significant benefit for deliberate hypotension in reducing transfusion requirements (-667 mL of blood transfused; 95% CI: -963, -370). Deliberate hypotension was not shown to reduce the duration of surgery (-1.9 min of surgery; 95% CI: -7.2, 3.5) or improve surgical conditions (surgical field quality rating -0.5; 95% CI: -1.1, 0.2). CONCLUSION: This review provides some support for the use of deliberate hypotension in reducing blood loss and transfusion requirements in orthopedic surgery, but these results are tempered by the small sample sizes and poor methodological quality of published studies.  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