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   89843篇
  免费   8092篇
  国内免费   6593篇
耳鼻咽喉   708篇
儿科学   1089篇
妇产科学   1083篇
基础医学   10996篇
口腔科学   1706篇
临床医学   12281篇
内科学   13708篇
皮肤病学   907篇
神经病学   4839篇
特种医学   3595篇
外国民族医学   61篇
外科学   8636篇
综合类   15005篇
现状与发展   30篇
一般理论   3篇
预防医学   5308篇
眼科学   2565篇
药学   9164篇
  70篇
中国医学   4798篇
肿瘤学   7976篇
  2024年   317篇
  2023年   1646篇
  2022年   3850篇
  2021年   4680篇
  2020年   3508篇
  2019年   3073篇
  2018年   3158篇
  2017年   2892篇
  2016年   2633篇
  2015年   4164篇
  2014年   4964篇
  2013年   4240篇
  2012年   6336篇
  2011年   7163篇
  2010年   4358篇
  2009年   3340篇
  2008年   4239篇
  2007年   4566篇
  2006年   4464篇
  2005年   4592篇
  2004年   2809篇
  2003年   2563篇
  2002年   2243篇
  2001年   1939篇
  2000年   2170篇
  1999年   2525篇
  1998年   1791篇
  1997年   1737篇
  1996年   1342篇
  1995年   1164篇
  1994年   999篇
  1993年   700篇
  1992年   740篇
  1991年   644篇
  1990年   587篇
  1989年   528篇
  1988年   438篇
  1987年   391篇
  1986年   296篇
  1985年   235篇
  1984年   118篇
  1983年   91篇
  1982年   65篇
  1981年   74篇
  1980年   54篇
  1979年   34篇
  1978年   8篇
  1977年   18篇
  1976年   25篇
  1975年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
对16例垂体腺瘤采用单侧鼻前庭切口经蝶切除,效果满意,既可减少手术创伤,又缩短了手术距离,且避免了美容缺陷,是一种设计巧妙,较为实用的手术方法,尤其适用于生长激素腺瘤。  相似文献   
33.
34.
35.
36.
37.
Nuclear factor-kappaB (NF-kappaB) plays a key role in inflammation, which is involved in the development of cerebral vasospasm after subarachnoid hemorrhage (SAH). In the present study, we assessed the potential role of NF-kappaB in regulation of cerebral vasospasm. Nuclear factor-kappaB DNA-binding activity was measured in cultured vascular smooth muscle cells (VSMCs) treated with hemolysate and pyrrolidine dithiocarbamate (PDTC, 80 micromol/L), an inhibitor of NF-kappaB. Forty-two rabbits were divided into three groups: control, SAH, and PDTC groups (n=14 for each group). The caliber of the basilar artery was evaluated. Nuclear factor-kappaB DNA-binding activity and the gene expression levels of cytokines and adhesion molecules in the basilar artery were measured. Immunohistochemical study was performed to assess the expression and localization of tumor necrosis factor (TNF)-alpha, intercellular adhesion molecule (ICAM)-1, and myeloperoxidase (MPO). It was observed that NF-kappaB DNA-binding activity was significantly increased by treatment with hemolysate in cultured VSCMs, but this increase was suppressed by pretreatment with PDTC. Severe vasospasm was observed in the SAH group, which was attenuated in the PDTC group. Subarachnoid hemorrhage could induce increases of NF-kappaB DNA-binding activity and the gene expression levels of TNF-alpha, interleukin (IL)-1 beta, ICAM-1, and vascular cell adhesion molecule (VCAM)-1, which were reduced in the PDTC group. Immunohistochemical study demonstrated that the expression levels of TNF-alpha, ICAM-1, and MPO were all increased in the SAH group, but these increases were attenuated in the PDTC group. Our results suggest that NF-kappaB is activated in the arterial wall after SAH, which potentially leads to vasospasm development through induction of inflammatory response.  相似文献   
38.
PURPOSE: Type I IFNs (IFN-alpha/beta) have shown significant antitumor activity in preclinical models but limited efficacy and significant toxicity in clinical trials. We hypothesized that the antitumor activity of type I IFNs could be enhanced by chronic, low-dose systemic delivery and sought to test this in murine neuroblastoma models. EXPERIMENTAL DESIGN: Continuous liver-generated expression of human IFN-beta (hINF-beta) was achieved through a gene therapy-mediated approach using adeno-associated virus vectors encoding hIFN-beta (AAV hINF-beta). Orthotopic localized retroperitoneal and disseminated models of neuroblastoma were established using three different xenografts. Immunohistochemical analysis and ELISA were used to evaluate the antiangiogenic effect of therapy. RESULTS: The development of both localized orthotopic (retroperitoneal) and disseminated neuroblastoma was prevented in all mice expressing hINF-beta. Continued growth of established retroperitoneal tumors, treated with AAV hINF-beta as monotherapy, was significantly restricted, and survival for mice with established, disseminated disease was significantly prolonged following administration of AAV hINF-beta. Analysis of treated tumors revealed a significant antiangiogenic effect. Mean intratumoral vessel density was diminished and expression of the angiogenic factors vascular endothelial growth factor and basic fibroblast growth factor were both decreased. Finally, combination therapy in which AAV hIFN-beta was used together with low-dose cyclophosphamide resulted in regression of both established retroperitoneal and disseminated disease. CONCLUSIONS: AAV-mediated delivery of hIFN-beta when used as monotherapy was able to restrict neuroblastoma growth due in part to inhibition of angiogenesis. When used in combination with conventional chemotherapy, AAV hIFN-beta was able to effect complete tumor regression.  相似文献   
39.
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