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   121652篇
  免费   7411篇
  国内免费   1596篇
耳鼻咽喉   1607篇
儿科学   3049篇
妇产科学   4191篇
基础医学   18600篇
口腔科学   3653篇
临床医学   9506篇
内科学   22541篇
皮肤病学   2527篇
神经病学   8187篇
特种医学   4109篇
外国民族医学   3篇
外科学   17283篇
综合类   5293篇
一般理论   38篇
预防医学   8838篇
眼科学   2875篇
药学   10347篇
中国医学   849篇
肿瘤学   7163篇
  2021年   1230篇
  2019年   1220篇
  2018年   1836篇
  2017年   1298篇
  2016年   1315篇
  2015年   1558篇
  2014年   2046篇
  2013年   2645篇
  2012年   3819篇
  2011年   4038篇
  2010年   2431篇
  2009年   2145篇
  2008年   3534篇
  2007年   3793篇
  2006年   3760篇
  2005年   3301篇
  2004年   3106篇
  2003年   2864篇
  2002年   2718篇
  2001年   6741篇
  2000年   6935篇
  1999年   5706篇
  1998年   1835篇
  1997年   1384篇
  1996年   943篇
  1995年   873篇
  1992年   3732篇
  1991年   3811篇
  1990年   3552篇
  1989年   3557篇
  1988年   3430篇
  1987年   3279篇
  1986年   3093篇
  1985年   2970篇
  1984年   2050篇
  1983年   1794篇
  1982年   985篇
  1979年   1909篇
  1978年   1185篇
  1977年   985篇
  1976年   918篇
  1975年   1190篇
  1974年   1359篇
  1973年   1412篇
  1972年   1356篇
  1971年   1243篇
  1970年   1135篇
  1969年   1114篇
  1968年   1024篇
  1967年   896篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
为探讨钙调素在慢性缺氧性肺动脉高压发病中的作用,将40只Wistar大鼠随机分为四组,I组为正常对照组,不接受任何处理。Ⅱ、Ⅲ、Ⅳ组为实验组,分别间断缺氧1、2、3周,而后采用火焰原子吸收分光光度法及磷酸二酯酶法测定四组大鼠肺组织Ca^2+含量及CaM活性。  相似文献   
52.
Eighty-nine cases of chronic bronchitis were matched against167 asymptomatic controls from the glass bangle industry ofFirozabad. Factors of age, social status, smoking habit andduration of exposure were studied. Duration of exposure wasfound to be a factor contributing significantly to the causationof disease. Requests for reprints should be addressed to: Dr B. N. Gupta, Division of Epidemilogy, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow P.O. Box 80, 226001, India  相似文献   
53.
BACKGROUND: Biliary tract lesions pose a dreaded complication of laparoscopic cholecystectomy. In a retrospective study we analyzed the clinical presentation, diagnostic and therapeutic management and outcome of 28 patients presenting with iatrogenic bile duct injuries. PATIENTS AND METHODS: Between 1994 and 2001 we treated 28 patients with bile duct lesions following laparoscopic cholecystectomy at our center. Operation notes and charts of all patients were reviewed systematically. A follow-up examination of each patient was performed after a median of 12 months (range 1-90). RESULTS: Twenty-two patients presented with major circumferential bile duct defect lesions. Less severe injuries (n=6) were two minor bile leaks, one bile duct stricture and three tangential lesions. Twenty-six patients were referred to our institution within 16 days (range 0-226 days). Six patients were treated by nonsurgical procedures: endoscopic stenting in four and percutaneous intervention in two. In one of the remaining patients a cystic duct leak was closed via laparotomy, and in 21 a hepaticojejunostomy was performed. Reconstruction of a hepaticojenunostomy was performed in two of these patients. Patients were dismissed from the hospital after a median of 13 days (range 4-156). Four patients presenting with generalized biliary peritonitis required prolonged intensive care. One or more episodes of cholangitis were seen in five patients during follow-up examinations. CONCLUSIONS: Major iatrogenic bile duct injuries are associated with high morbidity and prolonged hospitalization. Interdisciplinary cooperation and early referral to an experienced center is crucial in the management of patients suffering from this affliction. Cholangitis is a marked problem in the follow-up.  相似文献   
54.
55.
Physical therapy without anesthesia or plaster casts was used to treat 338 cases of clubfoot (CF). Our technique is based on progressive sequential manipulations at birth. We first reduce the varus and later the equinus component of the CF. The gentle stretches used in this technique are complemented by active physiotherapy stimulating the muscles, and then a simple splint is suited to the foot to fix its degree of realignment. When used alone, this technique achieves 77% good and fair results. In resistant cases, complementary surgery was used. We obtained 96% good and fair results.  相似文献   
56.
Effects of the MAO-A-inhibitor brofaromine (BRO), 10 mg/kg po after repeated (twice daily for 14 days) administration on the spontaneous behavior (exploratory and basal locomotor activities) and the exploratory activity modified by methoxamine, clonidine and d-amphetamine in male Wistar rats were studied in both light and dark phases of a diurnal cycle (L: 0700-1900 h). After single administration BRO in the light phase had no effects. In the dark phase BRO decreased the exploration (62% of control, p less than 0.01), increased the clonidine-evoked hypoactivity and amphetamine-evoked hyperactivity. The L-D differences occurred also after repeated administration. BRO in the light phase did not influence the exploration, decreased basal locomotor activity, did not change methoxamine and clonidine action and potentiated the action of amphetamine. In the dark phase, however, it did not influence the exploration and basal locomotor activity, intensified the methoxamine effect, and did not change the clonidine and amphetamine actions. The results demonstrate that the effects of BRO on behavior in rats: 1) differ from the effects caused by other antidepressants which are not MAO inhibitors; 2) are phase-dependent after both single and repeated administration.  相似文献   
57.
M Y Fan  Z P Lum  X W Fu  L Levesque  I T Tai  A M Sun 《Diabetes》1990,39(4):519-522
Prolonged survival of pancreatic islet allografts implanted in diabetic BB rats was achieved by encapsulation of individual islets in a protective biocompatible alginate-polylysine-alginate membrane without immunosuppression. Intraperitoneal transplantation of the encapsulated islets reversed the diabetic state of the recipients within 3 days and maintained normoglycemia for 190 days. Normal body weight and urine volume were maintained during this period, and no cataracts were detected in the transplant recipients. In contrast, control rats receiving transplants of unencapsulated islets experienced normoglycemia for less than 2 wk. These results demonstrated that microencapsulation can protect allografted islets from both graft rejection and autoimmune destruction without immunosuppression in an animal model that mimics human insulin-dependent diabetes.  相似文献   
58.
59.
60.
The present authors investigated the excretion, distribution and pharmacokinetics of the novel potential antirheumatic agent flobufen and its active metabolite after p.o. and i.v. doses of 2, 10 and 50 mg/kg administered to rats. The drug is resorbed well from the digestive tract and mostly it is metabolized to the principal metabolite M, which is only slowly excreted from the organism mainly by renal clearance. Within the whole dose range the kinetics of the drug is linear. Binding of flobufen and M to proteins is high (95-99%). The highest concentrations of radioactive metabolites (mostly M) were found in the plasma, liver, lungs, kidneys, connective tissue and inflammatory foci. The penetration of metabolites through the placenta and excretion in human milk are relatively important.  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