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   10576篇
  免费   651篇
  国内免费   60篇
耳鼻咽喉   97篇
儿科学   394篇
妇产科学   163篇
基础医学   1177篇
口腔科学   352篇
临床医学   721篇
内科学   2427篇
皮肤病学   242篇
神经病学   508篇
特种医学   457篇
外科学   1412篇
综合类   201篇
一般理论   5篇
预防医学   603篇
眼科学   497篇
药学   983篇
中国医学   51篇
肿瘤学   997篇
  2023年   55篇
  2022年   129篇
  2021年   259篇
  2020年   138篇
  2019年   189篇
  2018年   254篇
  2017年   162篇
  2016年   196篇
  2015年   264篇
  2014年   332篇
  2013年   421篇
  2012年   618篇
  2011年   668篇
  2010年   343篇
  2009年   354篇
  2008年   473篇
  2007年   506篇
  2006年   514篇
  2005年   463篇
  2004年   436篇
  2003年   399篇
  2002年   364篇
  2001年   308篇
  2000年   314篇
  1999年   225篇
  1998年   123篇
  1997年   104篇
  1996年   88篇
  1995年   90篇
  1994年   61篇
  1993年   55篇
  1992年   162篇
  1991年   165篇
  1990年   166篇
  1989年   150篇
  1988年   147篇
  1987年   180篇
  1986年   147篇
  1985年   121篇
  1984年   119篇
  1983年   90篇
  1982年   59篇
  1980年   60篇
  1979年   67篇
  1977年   63篇
  1976年   67篇
  1975年   62篇
  1974年   82篇
  1973年   65篇
  1972年   55篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Endoscopic clips have been used mainly for control of gastrointestinal (GI) bleeding and occasionally for closure of GI perforations. However, closure of spontaneous esophageal perforation (Boerhaave's syndrome) by clipping has not been reported. We described successful non-surgical closure of spontaneous esophageal perforation by endoscopic clipping in a patient with bilateral pyopneumothorax and septicemia.  相似文献   
2.
3.
Molecular characterization of Wuchereria bancrofti is essential to develop suitable anti-filarial drugs and vaccines. We describe here isolation, sequence analysis and cloning of a partial cDNA of an enzyme superoxide dismutase from this parasite. The immunoscreening of a lambda zap W. bancrofti microfilarial (Mf) cDNA library with microfilaremic sera had resulted in the isolation of several seroreactive clones including, WbSOD. This clone contained a 309 bp insert and showed significant nucleotide and deduced amino acid sequence homologies to the superoxide dismutases of other nematode parasites. The antioxidant property of this enzyme may have important contribution in the defense mechanism of the parasite against host immune response.  相似文献   
4.
5.
6.
We targeted the MVNP gene to the OCL lineage in transgenic mice. These mice developed abnormal OCLs and bone lesions similar to those found in Paget's patients. These results show that persistent expression of MVNP in OCLs can induce pagetic-like bone lesions in vivo. INTRODUCTION: Paget's disease (PD) of bone is the second most common bone disease. Both genetic and viral factors have been implicated in its pathogenesis, but their exact roles in vivo are unclear. We previously reported that transfection of normal human osteoclast (OCL) precursors with the measles virus nucleocapsid (MVNP) or measles virus (MV) infection of bone marrow cells from transgenic mice expressing a MV receptor results in formation of pagetic-like OCLs. MATERIALS AND METHODS: Based on these in vitro studies, we determined if the MVNP gene from either an Edmonston-related strain of MV or a MVNP gene sequence derived from a patient with PD (P-MVNP), when targeted to cells in the OCL lineage of transgenic mice with the TRACP promoter (TRACP/MVNP mice), induced changes in bone similar to those found in PD. RESULTS: Bone marrow culture studies and histomorphometric analysis of bones from these mice showed that their OCLs displayed many of the features of pagetic OCLs and that they developed bone lesions that were similar to those in patients with PD. Furthermore, IL-6 seemed to be required for the development of the pagetic phenotype in OCLs from TRACP/MVNP mice. CONCLUSIONS: These results show that persistent expression of the MVNP gene in cells of the OCL lineage can induce pagetic-like bone lesions in vivo.  相似文献   
7.
P K Reddy  P H Lange 《Urology》1987,30(2):123-126
Cystoscopy using the flexible cystoscope was performed on 15 patients in the semiprone position. Ureteral catheters were placed to facilitate percutaneous nephrolithotomy in 8 patients, and indwelling ureteral stents were removed in 7. The procedure offers the urologist an additional technique in select situations.  相似文献   
8.
9.
Changes in carbohydrate metabolism were studied in midgut gland, muscle, and gill tissues of marine prawn Penaeus indicus exposed to a sublethal concentration (0.3 ppm) of phosphamidon. A significant decrease in glycogen and pyruvate and an increase in lactate content were observed in all phosphamidon-exposed prawn tissues after 96 hr. An increase in phosphorylase a and aldolase activity levels suggested the increased formation of triose sugars during phosphamidon toxicity. LDH activity was considerably decreased and an increment in lactate content was observed which indicates reduced mobilization of pyruvate into the citric acid cycle. Glucose-6-phosphate dehydrogenase activity was considerably increased, suggesting the enhanced oxidation of glucose in the hexose monophosphate shunt pathway. Krebs cycle enzymes such as NAD-isocitrate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase were found to be decreased, suggesting the impairment in mitochondrial oxidative metabolism due to the acute toxic impact of phosphamidon. Cytochrome-c oxidase and Mg2+ ATPase activity levels were also decreased considerably, suggesting impaired energy synthesis and breakdown during phosphamidon toxicity, as a result of reduced oxidation of glucose aerobically. The increase in acid and alkaline phosphatase activities indicates the enhanced breakdown of phosphate to release energy in view of inhibiton or impairment in the ATPase system during phosphamidon-induced stress. These results suggest that phosphamidon has a profound effect on the oxidative metabolism of prawn which results in the triggering of compensatory metabolic pathways for survivability.  相似文献   
10.
The modified dorsal lithotomy position is excellent for radical pelvic operations. Use of modified Krauss arm supports as stirrups, along with pneumatic devices that intermittently compress the legs, significantly reduces postoperative morbidity in patients who undergo operations in this position.  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