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   70124篇
  免费   5333篇
  国内免费   1757篇
耳鼻咽喉   640篇
儿科学   1570篇
妇产科学   1478篇
基础医学   8079篇
口腔科学   1368篇
临床医学   7176篇
内科学   14576篇
皮肤病学   1584篇
神经病学   4385篇
特种医学   1489篇
外国民族医学   6篇
外科学   8490篇
综合类   6297篇
现状与发展   2篇
一般理论   13篇
预防医学   6100篇
眼科学   1676篇
药学   5953篇
  53篇
中国医学   2341篇
肿瘤学   3938篇
  2024年   172篇
  2023年   795篇
  2022年   1857篇
  2021年   3026篇
  2020年   2072篇
  2019年   2134篇
  2018年   2352篇
  2017年   2021篇
  2016年   1770篇
  2015年   2500篇
  2014年   3315篇
  2013年   3935篇
  2012年   5847篇
  2011年   5903篇
  2010年   3878篇
  2009年   3426篇
  2008年   4355篇
  2007年   4336篇
  2006年   3871篇
  2005年   3608篇
  2004年   2861篇
  2003年   2780篇
  2002年   2280篇
  2001年   915篇
  2000年   838篇
  1999年   777篇
  1998年   437篇
  1997年   374篇
  1996年   339篇
  1995年   288篇
  1994年   244篇
  1993年   180篇
  1992年   336篇
  1991年   300篇
  1990年   274篇
  1989年   288篇
  1988年   243篇
  1987年   217篇
  1986年   194篇
  1985年   187篇
  1984年   138篇
  1983年   141篇
  1982年   100篇
  1981年   96篇
  1979年   111篇
  1977年   78篇
  1976年   75篇
  1975年   74篇
  1973年   77篇
  1972年   71篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
121.

Background  

To develop a sensitive and specific screening tool for knee and hip osteoarthritis in the general population of elderly people.  相似文献   
122.
宫腔镜手术电热损伤的研究   总被引:2,自引:1,他引:1  
目的探讨宫腔镜手术中各种电极在不同功率下对子宫组织电热损伤程度.方法设置电极功率为80~120 W,作用时间为3~5 s,作用于宫腔镜手术在体子宫内膜及肌层,在切下内膜组织及电极作用下方分别取材,通过HE染色观察电热损伤.结果不同电极子宫组织电热损伤有显著差异,滚球电极电热损伤最深,气化电极次之,环状电极最薄.结论子宫组织电热损伤程度与电极功率选择关系不大,而与电极形状密切相关.  相似文献   
123.

Objectives  

This study was designed to assess the prevalence of adverse drug reactions (ADRs) in the internal medicine wards of two teaching Hospitals, identify the most common ADRs, the principal medications involved, and determine the risk factors implicated in the occurrence of such ADRs.  相似文献   
124.
Levels of iron, copper, zinc and lead were determined in sediments and soft tissue of the oyster Crassostrea rhizophorae collected from Guacanayabo Gulf, Cuba. Metal-to-Iron ratio in sediments shows an average enrichment for Cu (5,1), Pb (11,7) and Zn (1,3) in the last 20 years. Metal concentrations found in soft tissue of C. rhizophorae are site dependent. The average biota-sediment accumulation factors (BSAFs) obtained for Fe, Cu and Pb are less than unity in all cases, indicating that only a little fraction of Cu and Pb in the sediments is bioavailable, independently of their enrichments. Zinc has an average BSAF value of 2.4 and may represent a serious impact in the area. The concentrations of zinc and copper in some of the oysters are above typical public health recommended limits.  相似文献   
125.
Objective The objective of the study was to determine the outcomes for primary gastrointestinal melanomas (PGIM). Material and methods The Surveillance, Epidemiology, and End Results database (1973–2004) was queried. Results Overall, 659 cases of PGIM were identified. The annual incidence of PGIM was approximately 0.47 cases per million in 2000. Overall median survival time was 17 months. Tumors were identified in the oral–nasopharynx (32.8%), anal canal (31.4%), rectum (22.2%), esophagus (5.9%), stomach (2.7%), small bowel (2.3%), gallbladder (1.4%), and large bowel (0.9%). Univariate analysis demonstrated age, tumor location, stage, surgery, and lymph node status were significant predictors of improved survival. MST has not been reached for tumors located in the large bowel, while tumors located in the stomach demonstrated the shortest median survival (5 months). Improvement in MST was observed for those patients undergoing surgical resection. The presence of lymph node involvement conferred a poorer prognosis. Multivariate analysis of the cohort identified that location, advanced tumor stage, failure to undertake surgical resection, positive lymph node status, and age were all independent predictors of poorer outcome. Conclusion PGIM occurs most often in the oral–nasopharynx and anal canal. Surgical extirpation is the only identifiable treatment modality that significantly improves survival.  相似文献   
126.
INTRODUCTION : In patients with common bile duct (CBD) stones, the diameter of the CBD is usually dilated. After surgery, the behavior of CBD diameter is not clearly known. OBJECTIVE : To determine at a late follow-up the width of CBD before and after choledochostomy for CBD stones. MATERIAL AND METHODS : In this prospective study, 39 patients with gallstones and CBD stones were included. They were 30 women and 9 men with a mean age of 52.6 years. In all ultrasound, determination of the CBD caliber before and 12 years after surgery was performed. RESULTS : The mean value of the inner diameter of the CBD before surgery was 11.6 and 12.3 mm in patients below or above 60 years, respectively. Measurement 12 years after surgery showed a mean decrease of nearly 50% of preoperative values, which was highly significant (p < 0.0001). However, either below or above 60 years, only 75% of the patients showed this decrease, whereas 25% remained unchanged. CONCLUSION : The dilated preoperative CBD returns to normal or near normal values in 3/4 of the patients after surgical exploration of the CBD and extraction of the stones.  相似文献   
127.
Familial hypercholesterolaemia is a frequent, inherited, monogenic disorder, associated with accelerated development of atherosclerotic disease leading to coronary artery disease. Life expectancy of patients with familial hypercholesterolaemia is reduced by 15-30 years unless they are adequately treated with lipid-lowering therapy. Given the chronic nature of this disease, the selection of a therapeutic approach should be strongly based on its long-term safety and tolerability. The introduction of HMG-CoA reductase inhibitors has revolutionised the treatment of familial hypercholesterolaemia.Simvastatin 40-80 mg/day effectively reduces serum low density lipoprotein (LDL)-cholesterol levels. Furthermore, simvastatin reduces triglycerides and mildly raises high density lipoprotein-cholesterol levels. In addition to the hypolipidaemic effect, other potentially important effects, such as improvement of endothelial function and reduction of LDL oxidation and vascular inflammation, have been associated with HMG-CoA reductase inhibitor therapy. Simvastatin has also been shown to abolish the progression, and even facilitate the regression, of existing human atherosclerotic lesions.The good safety and tolerability profile of simvastatin is clearly highlighted by the low rate of therapy discontinuation observed in several population-based clinical trials. The most common adverse events leading to the discontinuation of therapy are gastrointestinal upset and headache. Asymptomatic elevations in liver transaminase levels and myopathy are uncommon.The overwhelming clinical evidence regarding the long-term use of HMG-CoA reductase inhibitor therapy in patients with familial hypercholesterolaemia together with the long-term safety data (particularly relating to simvastatin) provide support for the use of this drug as a first-line agent when pharmacological treatment is indicated. Early intervention with simvastatin treatment can be successfully implemented with favourable economic benefits.  相似文献   
128.
129.
130.
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