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   701092篇
  免费   66280篇
  国内免费   3028篇
耳鼻咽喉   12355篇
儿科学   23101篇
妇产科学   16359篇
基础医学   93257篇
口腔科学   16362篇
临床医学   74649篇
内科学   147462篇
皮肤病学   19803篇
神经病学   54477篇
特种医学   26263篇
外国民族医学   63篇
外科学   124501篇
综合类   9034篇
现状与发展   73篇
一般理论   174篇
预防医学   49334篇
眼科学   16156篇
药学   44087篇
中国医学   1046篇
肿瘤学   41844篇
  2021年   7900篇
  2020年   8651篇
  2019年   7003篇
  2018年   13971篇
  2017年   11993篇
  2016年   13423篇
  2015年   14058篇
  2014年   23074篇
  2013年   27042篇
  2012年   22124篇
  2011年   23485篇
  2010年   20360篇
  2009年   23261篇
  2008年   22021篇
  2007年   21386篇
  2006年   23599篇
  2005年   20096篇
  2004年   18845篇
  2003年   16891篇
  2002年   16629篇
  2001年   27901篇
  2000年   28107篇
  1999年   23810篇
  1998年   9185篇
  1997年   8232篇
  1996年   8410篇
  1995年   7830篇
  1994年   6271篇
  1993年   5710篇
  1992年   17115篇
  1991年   17705篇
  1990年   17477篇
  1989年   16976篇
  1988年   15587篇
  1987年   15287篇
  1986年   14483篇
  1985年   13689篇
  1984年   10185篇
  1983年   8777篇
  1979年   9726篇
  1978年   7183篇
  1977年   6164篇
  1976年   5830篇
  1975年   6679篇
  1974年   7863篇
  1973年   7362篇
  1972年   7264篇
  1971年   6883篇
  1970年   6427篇
  1969年   5965篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
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   
32.
Traumatic injuries of the elbow are frequent in patients of all ages but are particularly common in young children and adolescents engaged in normal play and athletic competition. Injury may result primarily due to direct trauma or may be secondary to transmission of forces through the elbow following a fall on an outstretched hand. In middle-aged and older individuals, chronic repetitive injuries tend to predominate. In all patients, radiographs remain the initial imaging study of choice. Many patients, however, may need advanced cross-sectional imaging (i.e. MRI, CT, or ultrasound) either at presentation or during the course of their treatment and follow-up. This article reviews the imaging appearance of common acute and chronic traumatic disorders of the elbow.  相似文献   
33.
34.
CONTEXT: The physician assistant profession has been moving toward requiring master's degrees for new practitioners, but some argue this could change the face of the discipline. PURPOSE: To see if there is an association between physician assistants' academic degrees and practice in primary care, in rural areas, and with the medically underserved. METHODS: Surveys were sent to 880 graduates of the first 32 University of Washington physician assistant classes through 2000. Respondents noted their academic degree at program entry and the highest degree attained at any time up to the time of survey. Relationships between practice characteristics and academic degree levels were tested by unadjusted odds ratios and logistic regression after controlling for year of graduation and sex. RESULTS: Of the 478 respondents, 54% worked in primary care, about 30% practiced in nonmetropolitan communities, and 42% reported providing care for the medically underserved. Respondents with no degree (33% of total at entry, 24% at survey) were significantly more likely than degree holders to work in primary care and nonmetropolitan areas. Respondents with no degree at program entry were significantly more likely, and those with no degree at the time of the survey were marginally more likely, to self-report work with the medically underserved. CONCLUSION: Respondents with no academic degree are significantly more likely to demonstrate a commitment to primary, rural, and underserved health care. These findings may inform the national debate about the impact of required advanced degrees on the practice patterns of nonphysician providers.  相似文献   
35.
36.
37.
AIMS: To examine the effects of agents that alter potassium adenosine triphosphate (KATP) channel activity in beta-cells on cognitive function and counterregulatory hormone responses during acute hypoglycaemia, given the physiological similarities between the pancreatic beta-cell and the hypothalamic glucose-sensitive neurones (GSN) and the widespread distribution of sulphonylurea receptors in neuronal cells throughout the brain. METHODS: Ten healthy males were studied on four occasions and in random order underwent three stepped hypoglycaemic (plasma glucose aims: 3.4, 2.8, 2.4 mmol/l) and one euglycaemic (plasma glucose aim: 5 mmol/l) insulin clamps. Prior to each hypoglycaemic study, volunteers received either 10 mg glibenclamide, or 5 mg/kg diazoxide or placebo orally. Cognitive function, symptom scores and counterregulatory hormone responses were measured at each glycaemic level. RESULTS: There was no statistically significant effect of either drug on the symptoms generated or the counterregulatory hormonal response during hypoglycaemia. However, cognitive function was better preserved during hypoglycaemia in the glibenclamide-treated arm, particularly four-choice reaction time which deteriorated at a plasma glucose 2.5 mmol/l compared with 3.0 mmol/l with diazoxide (P = 0.015) and 2.9 mmol/l with placebo (P = 0.114). CONCLUSIONS: Single doses of pharmacological agents which alter membrane KATP channel activity do not affect the counterregulatory response to hypoglycaemia but may modify cognitive function during cerebral glucopenia. The unexpected effects of glibenclamide on cortical function suggest a novel action of sulphonylureas that warrants further investigation.  相似文献   
38.
The reliable change index (RCI) expresses change relative to its associated error, and is useful in the identification of post-operative cognitive dysfunction (POCD). This paper examines four common RCIs that each account for error in different ways. Three rules incorporate a constant correction for practice effects and are contrasted with the standard RCI that had no correction for practice. These rules are applied to 160 patients undergoing coronary artery bypass graft (CABG) surgery who completed neuropsychological assessments preoperatively and 1 week post-operatively using error and reliability data from a comparable healthy non-surgical control group. The rules all identify POCD in a similar proportion of patients, but the use of the within subject standard deviation, expressing the effects of random error, as an error estimate is a theoretically appropriate denominator when a constant error correction, removing the effects of systematic error, is deducted from the numerator in a RCI.  相似文献   
39.
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   
40.
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