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   32827篇
  免费   2249篇
  国内免费   110篇
耳鼻咽喉   258篇
儿科学   1320篇
妇产科学   980篇
基础医学   4447篇
口腔科学   404篇
临床医学   4225篇
内科学   6316篇
皮肤病学   630篇
神经病学   3502篇
特种医学   736篇
外国民族医学   1篇
外科学   3185篇
综合类   341篇
一般理论   32篇
预防医学   3848篇
眼科学   558篇
药学   1915篇
中国医学   56篇
肿瘤学   2432篇
  2024年   39篇
  2023年   254篇
  2022年   463篇
  2021年   921篇
  2020年   578篇
  2019年   958篇
  2018年   1028篇
  2017年   722篇
  2016年   829篇
  2015年   861篇
  2014年   1219篇
  2013年   1794篇
  2012年   2658篇
  2011年   2718篇
  2010年   1509篇
  2009年   1247篇
  2008年   2175篇
  2007年   2346篇
  2006年   2271篇
  2005年   2147篇
  2004年   1910篇
  2003年   1771篇
  2002年   1698篇
  2001年   230篇
  2000年   173篇
  1999年   221篇
  1998年   320篇
  1997年   285篇
  1996年   218篇
  1995年   188篇
  1994年   152篇
  1993年   186篇
  1992年   112篇
  1991年   92篇
  1990年   71篇
  1989年   70篇
  1988年   82篇
  1987年   43篇
  1986年   47篇
  1985年   45篇
  1984年   53篇
  1983年   54篇
  1982年   54篇
  1981年   46篇
  1980年   53篇
  1979年   33篇
  1978年   39篇
  1977年   24篇
  1974年   17篇
  1973年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
BACKGROUND: Results of conservative management of epithelial ovarian cancer (EOC) remain controversial in the literature. The aim of this study was to assess the clinical outcomes and fertility following fertility-sparing surgical management of EOC in a retrospective multicentre study. METHODS: A multicentre retrospective study was performed by members of two French groups. Six inclusion criteria were defined: (i) Histological review by the same pathologist; (ii) age < or =40 years; (iii) conservative management; (iv) complete peritoneal staging; (v) delivery of a platinum-based chemotherapy in stage > or = IC; and (vi) follow-up >1 year. RESULTS: Thirty-four patients fulfilled the inclusion criteria: 30 had stage IA disease; three had stage IC and one had stage IIA. Eleven patients had recurrence: 10 patients had invasive disease and one had borderline recurrence. Among 10 patients with invasive recurrence, initial stage and grade were: stage IA G1, n = 1; stage IA G2, n = 4; stage IA G3, n = 1; and stage> or = IC, n = 4. All patients with stage > IA had recurrence. Ten pregnancies were observed in nine patients. CONCLUSION: Conservative surgery for patients with EOC could be considered in young patients with stage IA G1 disease. This procedure should not be performed in patients with FIGO stage > IA.  相似文献   
103.
Adoptive immunotherapy for posttransplantation viral infections.   总被引:1,自引:0,他引:1  
Viral diseases are a major cause of morbidity and mortality after hemopoietic stem cell transplantation. Because viral complications in these patients are clearly associated with the lack of recovery of virus-specific cellular immune responses, reconstitution of the host with in vitro expanded cytotoxic T lymphocytes is a potential approach to prevent and treat these diseases. Initial clinical studies of cytomegalovirus and Epstein-Barr virus in human stem cell transplant patients have shown that adoptively transferred donor-derived virus-specific T cells may restore protective immunity and control established infections. Preclinical studies are evaluating this approach for other viruses while strategies for generating T cells specific for multiple viruses to provide broader protection are being evaluated in clinical trials. The use of genetically modified T cells or the use of newer suicide genes may result in improved safety and efficacy.  相似文献   
104.
The development of hepatic microvascular heterogeneity after birth, and its temporal relationship to the development of parenchymal cell plates have received little attention. As a result, the morphogenesis of some of the parameters contributing to this heterogeneity in suckling and weaned rats was studied as a function of time between postpartum days 4 and 30 using in vivo light microscopic, electron microscopic, and immunocytochemical methods. During the early suckling period, the sinusoid network is highly anastomotic, with little evidence of zonation, and the parenchymal cell plates contain multiple cells and are irregularly arranged throughout the lobule. Sinusoidal endothelial fenestration is sparse at 4 days, but phagocytic Kupffer cell (KC) function already exists and exhibits zonal heterogeneity, with more cells located in the periportal zone. With increasing age, endothelial fenestrae increase and organize as sieve plates. Widened centrilobular radial sinusoids form through a loss ("drop-out") of intersinusoidal sinusoids (ISS). Concomitantly, the associated cell plates straighten and become one cell thick. Hepatocyte DNA synthesis and mitosis are higher in the periportal zone, which retains thickened cell plates and anastomotic sinusoids. The centrilobular sinusoids may widen to accommodate the increased volume of blood that results from the loss of ISS as well as the increased numbers of periportal sinusoids containing flow that feed these vessels. KC phagocytic activity increases during the suckling period concomitant with an increase of gut-derived endotoxin in the portal blood, which suggests that the KCs may be releasing mediators that affect sinusoid diameter, blood flow, endothelial fenestration, and perhaps parenchymal growth either directly or through the stimulation of growth factors.  相似文献   
105.
106.
EXT1 and EXT2 are genes that have been shown to cause hereditary multiple exostosis (HME), a syndrome marked by the formation of bony growths juxtaposed to the growth plate. These genes are members of a growing family of proteins with glycosyltransferase activity required for the synthesis of heparan sulfate chains. This protein activity is predicted to play a role in the expression of proteoglycans on the cell surface and in the extracellular matrix. We and others have previously suggested that a two-hit mutational model applies to the development of an exostosis where a germline mutation coupled with a somatic mutation results in the loss of EXT1 or EXT2 function and subsequent tumor formation. We report the direct sequencing and loss of heterozygosity (LOH) analysis of 12 exostoses from 10 HME families, 4 solitary exostoses, and their corresponding constitutional DNA. Of the 16 exostoses screened, we find only one solitary case in which two somatic mutations, a deletion and an LOH, are present. This provides limited support for the two-hit hypothesis involving the EXT1 and EXT2 genes for the development of an exostosis. Alternative models are developed based on the functional significance of EXT proteins in heparan sulfate biosynthesis.  相似文献   
107.
108.
109.
110.
In the current study, we investigated the effect of growth of FasL+ tumors in vivo on the functions of peripheral lymphoid organs and the liver. Injection of FasL+ LSA tumor cells into syngeneic C57BL/6 wild-type mice but not C57BL/6 lpr/lpr (Fas-deficient) mice caused apoptosis in splenocytes. Spleen cells expressing CD3, CD4, CD8, CD19, Mac-3, and CD44 were all susceptible to tumor-induced apoptosis. Also, activated T cells were more sensitive to apoptosis induced by LSA tumor cell lysate when compared to naïve T cells. In contrast, anti-Fas Abs (Jo2) induced apoptosis in only activated but not naïve T cells. When the LSA tumor-bearing mice were injected with a superantigen (SEA), these mice showed a significant decrease in the expansion of SEA-reactive Vβ3+ and Vβ11+ T cells. When injected into syngeneic mice, the FasL+ LSA tumor cells caused hepatotoxicity, as indicated by an increase in serum aspartate aminotransferase (AST) levels. Interestingly, Fas-deficient C57BL/6 lpr/lpr mice also showed significant AST levels in the serum following LSA tumor growth. Moreover, hepatocytes isolated from C57BL/6 wild-type and C57BL/6 lpr/lpr mice were equally susceptible to apoptosis induced by LSA tumor cell lysate in vitro. Using cDNA array, LSA tumor cells were found to express several cytokine genes including IL-2, IL-7, IL-11, IL-13, IL-16, lymphotoxin β, and tumor necrosis factor β. Together, these data suggested that, in mice bearing FasL+ LSA tumor, the immunotoxicity is FasL-based, whereas the hepatotoxicity, at least in part, may be FasL-independent.  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