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   363046篇
  免费   28284篇
  国内免费   8767篇
耳鼻咽喉   3798篇
儿科学   7717篇
妇产科学   6117篇
基础医学   45745篇
口腔科学   6291篇
临床医学   39544篇
内科学   69730篇
皮肤病学   4444篇
神经病学   30304篇
特种医学   12662篇
外国民族医学   86篇
外科学   50126篇
综合类   22044篇
现状与发展   25篇
一般理论   326篇
预防医学   29329篇
眼科学   9598篇
药学   28876篇
  129篇
中国医学   6918篇
肿瘤学   26288篇
  2024年   601篇
  2023年   3180篇
  2022年   7082篇
  2021年   11419篇
  2020年   7844篇
  2019年   9183篇
  2018年   10024篇
  2017年   8061篇
  2016年   8528篇
  2015年   11042篇
  2014年   15057篇
  2013年   17636篇
  2012年   26907篇
  2011年   28410篇
  2010年   16851篇
  2009年   14330篇
  2008年   22578篇
  2007年   23380篇
  2006年   22981篇
  2005年   22666篇
  2004年   19778篇
  2003年   18399篇
  2002年   16869篇
  2001年   4210篇
  2000年   3654篇
  1999年   4524篇
  1998年   4431篇
  1997年   3876篇
  1996年   3207篇
  1995年   3008篇
  1994年   2515篇
  1993年   2062篇
  1992年   1843篇
  1991年   1675篇
  1990年   1476篇
  1989年   1369篇
  1988年   1372篇
  1987年   1281篇
  1986年   1266篇
  1985年   1210篇
  1984年   1392篇
  1983年   1254篇
  1982年   1436篇
  1981年   1382篇
  1980年   1200篇
  1979年   814篇
  1978年   805篇
  1977年   669篇
  1976年   605篇
  1974年   534篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
X-linked hyper-immunoglobulin M (IgM) syndrome (XHIGM) is a rare genetic primary immunodeficiency disease caused by mutations of the CD40 ligand (CD40L) gene with normal or elevated levels of IgM and markedly decreased serum IgG, IgA, and IgE. Liver disease may occur as a clinical manifestation in XHIGM. This complication appears to increase with age. We report an 18-year-old male patient who had recurrent episodes of acalculous cholecystitis (AC) and sclerosing cholangitis (SC). The diagnosis of XHIGM was confirmed by the finding of CD40L expression < 1% of normal and a tyrosine 169 asparaginase (t526a) mutation in exon 5 (the tumor necrosis factor domain) of the CD40L gene. The patient had direct hyperbilirubinemia (direct bilirubin 5.5 mg/dL, total bilirubin 8.7 mg/dL), cholestasis (alkaline phosphatase 1133 U/L, gamma-glutamyl transferase 1019 U/L) and elevated transaminases (aspartate aminotransferase 70 U/L, alanine aminotransferase 101 U/L). Findings on abdominal ultrasound and abdominal computed tomography were compatible with AC. After the fourth episode of cholecystitis, cholecystectomy and liver biopsy were performed. Operative cholangiography revealed poor opacification of the hepatic duct and proximal common bile duct; the upstream intrahepatic bile ducts were not visualized. The biopsy specimen showed marked fibrosis of the portal areas. Enterococcus species was cultured from the bile. Children or adolescents with recurrent AC and SC should be evaluated for an underlying immunodeficiency syndrome such as XHIGM.  相似文献   
62.
63.
64.
65.
66.
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   
67.
68.
Experiments were performed to determine the effect of pin channel preparation with standard and reduction speed handpieces, and pin seating by hand and with motor drive. The greatest retention was achieved by preparation with a standard handpiece at 6000 rpm, and manual pin placement with a hand driver. The most consistent retention values were achieved using the reduction handpiece. All preparation and placement combinations examined produced a clinically acceptable result.  相似文献   
69.
D. W. Barnes, D. A. Sirbasku & G. H. Sato, (eds.): Cell culture methods for molecular and cell biology. P. M. Gootman (ed.): Developmental neurobiology of the autonomic nervous system. M. Sandler, C. Feuerstein, B. Scatton (eds.): Neurotransmitter interactions in the basal ganglia. Harry M. Zimmerman (ed). Progress in neuropathology. M. Yahr & K. J. Bergmann (eds.): Parkinson's disease. G. Bock & M. O'Connor (eds.): Selective neuronal death. H. Julia Hannay (ed.): Experimental techniques in human neuropsychology. D. Papakostopoulos, S. Butler, I. Martin (eds.): Clinical and experimental neuropsychophysiology J. C. Rothwell: Control of human voluntary movement.  相似文献   
70.
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