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   1431221篇
  免费   105498篇
  国内免费   4889篇
耳鼻咽喉   17775篇
儿科学   46650篇
妇产科学   38632篇
基础医学   211526篇
口腔科学   39497篇
临床医学   138279篇
内科学   279604篇
皮肤病学   28824篇
神经病学   121338篇
特种医学   50480篇
外国民族医学   367篇
外科学   192553篇
综合类   29126篇
现状与发展   1篇
一般理论   503篇
预防医学   123875篇
眼科学   30516篇
药学   105563篇
  6篇
中国医学   3527篇
肿瘤学   82966篇
  2021年   14228篇
  2019年   14391篇
  2018年   19447篇
  2017年   14693篇
  2016年   16056篇
  2015年   18252篇
  2014年   24844篇
  2013年   37336篇
  2012年   52209篇
  2011年   55186篇
  2010年   31631篇
  2009年   28763篇
  2008年   49285篇
  2007年   51662篇
  2006年   51201篇
  2005年   49242篇
  2004年   46626篇
  2003年   44055篇
  2002年   42358篇
  2001年   61323篇
  2000年   62834篇
  1999年   52802篇
  1998年   15306篇
  1997年   13853篇
  1996年   13615篇
  1995年   12870篇
  1994年   12025篇
  1993年   11238篇
  1992年   41819篇
  1991年   40929篇
  1990年   39613篇
  1989年   37503篇
  1988年   34734篇
  1987年   33822篇
  1986年   32294篇
  1985年   30733篇
  1984年   23155篇
  1983年   19706篇
  1982年   11896篇
  1979年   20867篇
  1978年   14883篇
  1977年   12126篇
  1976年   11931篇
  1975年   12147篇
  1974年   14842篇
  1973年   14496篇
  1972年   13381篇
  1971年   12434篇
  1970年   11504篇
  1969年   10423篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
Spinocerebellar ataxia (SCA) types 2 and 3 are autosomal-dominant neurodegenerative disorders caused by mutations in two different genes. We identified mutations for SCA2 and SCA3 segregating simultaneously in a single Brazilian family. The index patient had SCA2, whereas her two second-degree cousins had SCA3. Disease was more rapidly progressive in the SCA2 patient, who presented severe brainstem and pancerebellar atrophy, as opposed to the two SCA3 patients, who had only mild cerebellar vermian atrophy. In such situations, molecular confirmation of all patients may avoid misdiagnosis of SCA subtypes and eventual errors in predictive testing of unaffected family members.  相似文献   
73.
Research coordinators in intensive care are a growing specialty about which little is known. This cross-sectional study surveyed the Australia and New Zealand Intensive Care Research Coordinators' Group (n = 49) regarding demographics, education, employment history, job structure, and role content. Most research coordinators were highly qualified and experienced nurses who undertake pharmaceutical trials, multicenter projects, departmental medical and nursing research, audits and data registries, and their own projects.  相似文献   
74.
75.
Mucosal trypsin, a protease-activated receptor (PAR) stimulant, may have an endogenous bronchoprotective role on airway smooth muscle. To test this possibility the effects of lumenal trypsin on airway tone in segments of pig bronchus were tested. Bronchial segments from pigs were mounted in an organ chamber containing Kreb's solution. Contractions were assessed from isovolumetric lumen pressure induced by acetylcholine (ACh) or carbachol added to the adventitia. Trypsin, added to the airway lumen (300 microg x mL(-1)), had no immediate effect on smooth muscle tone but suppressed ACh-induced contractions after 60 min, for at least 3 h. Synthetic activating peptides (AP) for PAR1, PAR2 or PAR3 were without effect, but PAR4 AP caused rapid, weak suppression of contractions. Lumenal thrombin was without effect and did not prevent the effects of trypsin. Effects of trypsin were reduced by N(omega)-nitro-L-arginine methyl ester but not indomethacin. Trypsin, thrombin and PAR4 AP released prostaglandin E2. Adventitially, trypsin, thrombin and PAR4 AP (but not PAR2 AP) relaxed carbachol-toned airways after <3 min. The findings of this study show that trypsin causes delayed and persistent bronchoprotection by interacting with airway cells accessible from the lumen. The signalling mechanism may involve nitric oxide synthase but not prostanoids or protease-activated receptors.  相似文献   
76.
AIMS: To establish all-cause and cause-specific death rates, and risk factors for mortality in insulin-treated diabetic individuals living in the province of Canterbury, New Zealand. METHODS: Insulin-treated diabetic subjects (n = 995) on the Canterbury Diabetes Registry were followed up over 15 years and vital status determined. Death rates were standardized and hazard regression was used to model the effects of demographic covariates on relative survival time. RESULTS: There were 419 deaths in 11 226.3 person-years of follow-up with a standardized mortality ratio (SMR) of 2.0 (95% confidence interval (CI) 1.8-2.2). Relative mortality was greatest for the group aged 0-29 years (SMR 3.0 (95% CI 2.4-3.7)). After controlling for diabetes duration and gender, a 10-year increment in age of onset was associated with a 33% decrease in relative hazard (95% CI 29-36%), indicating that excess mortality due to diabetes declines with rising age of onset. After controlling for age of onset and gender, each 10-year increment in duration of diabetes is associated with a 26% decrease in relative hazard (95% CI 24-29%), indicating that with longer survival the mortality hazard approaches the general population hazard. Relative mortalities were increased for cardiovascular, renal and respiratory disease, but not malignancy. Relative mortality from acute metabolic complications was increased in the subgroup with age of onset of diabetes < 30 years and requiring insulin within 1 year of diagnosis. CONCLUSIONS: Mortality rates are high for insulin-treated diabetic individuals relative to the general population.  相似文献   
77.
Social phobia, fear of negative evaluation and harm avoidance.   总被引:1,自引:0,他引:1  
This naturalistic, prospective investigation examined the role of fear of negative evaluation and the personality trait of harm avoidance in the anxiety levels of treated social phobia patients. One hundred and fifty-seven patients with DSM-IV social phobia were assessed before starting treatment and were then followed for up to two years. As expected, greater fear of negative evaluation and higher scores of harm avoidance were associated with greater anxiety at the 6 month follow-up, and harm avoidance remained a significant predictor at 24 months. However, no evidence was found for an interaction between the personality and cognitive variables examined. The findings are discussed in terms of the relative independence of these factors, as well as their potential implications for the treatment of this disorder.  相似文献   
78.
Atherosclerotic renal artery stenosis (ARAS) may cause hypertension, progressive renal failure, and recurrent pulmonary edema. It typically occurs in high risk patients with coexistent vascular disease elsewhere. Most patients with ARAS are likely to die from coronary heart disease or stroke before end-stage renal failure occurs. Recent controlled trials have shown that most patients undergoing angioplasty to treat renovascular hypertension still need antihypertensive agents 6 or 12 months after the procedure. Nevertheless, the number of antihypertensive agents required to control blood pressure adequately is lower following angioplasty than for medication alone. Trials assessing the value of revascularization for preserving renal function or preventing clinical events are only in the early recruitment phase. Revascularization should be undertaken in patients with ARAS and resistant hypertension or heart failure, and probably in those with rapidly deteriorating renal function or with an increase in plasma creatinine levels during angiotensin-converting enzyme inhibition. With or without revascularization, medical therapy using antihypertensive, hypolipidemic and antiplatelet agents is necessary in almost all cases.  相似文献   
79.
80.
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