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   8368篇
  免费   355篇
  国内免费   69篇
耳鼻咽喉   208篇
儿科学   244篇
妇产科学   106篇
基础医学   1377篇
口腔科学   134篇
临床医学   428篇
内科学   2030篇
皮肤病学   167篇
神经病学   603篇
特种医学   284篇
外科学   1344篇
综合类   25篇
预防医学   147篇
眼科学   107篇
药学   502篇
中国医学   24篇
肿瘤学   1062篇
  2023年   41篇
  2022年   95篇
  2021年   209篇
  2020年   101篇
  2019年   125篇
  2018年   165篇
  2017年   142篇
  2016年   164篇
  2015年   163篇
  2014年   236篇
  2013年   293篇
  2012年   480篇
  2011年   583篇
  2010年   333篇
  2009年   251篇
  2008年   434篇
  2007年   510篇
  2006年   512篇
  2005年   545篇
  2004年   567篇
  2003年   531篇
  2002年   607篇
  2001年   119篇
  2000年   75篇
  1999年   112篇
  1998年   135篇
  1997年   138篇
  1996年   114篇
  1995年   80篇
  1994年   100篇
  1993年   101篇
  1992年   77篇
  1991年   71篇
  1990年   60篇
  1989年   52篇
  1988年   51篇
  1987年   46篇
  1986年   46篇
  1985年   38篇
  1984年   41篇
  1983年   25篇
  1982年   32篇
  1981年   25篇
  1980年   30篇
  1979年   15篇
  1978年   24篇
  1977年   11篇
  1976年   17篇
  1974年   8篇
  1973年   12篇
排序方式: 共有8792条查询结果,搜索用时 15 毫秒
121.
122.
123.
Experimental autoimmune myocarditis (EAM) in rats is an animal model of human giant cell myocarditis and postmyocarditis dilated cardiomyopathy. As the heart consumes large amounts of energy, heart diseases such as myocarditis and dilated cardiomyopathy are associated with abnormal fatty acid metabolism. Peroxisome proliferator-activated receptor alpha (PPARalpha) is a regulator of the oxidative degradation of fatty acids. To investigate the role of PPARalpha in EAM, fenofibrate (a PPARalpha activator) was administered to rats with EAM for 4 weeks. Reductions in the ratios of both ventricular weight to body weight and the area of inflammatory lesions to the total area of heart sections were observed in fenofibrate-treated rats when compared with controls. Fenofibrate ameliorated changes in serum albumin and sialic acid, which are markers of inflammation. Cardiac expression of interleukin-10 (IL-10) mRNA was more pronounced in the fenofibrate group than in the control group (1.3 +/- 0.2 vs 0.7 +/- 0.1; p < 0.01), and the area of intact myocardium correlated with the IL-10 mRNA level (p = 0.0297, r = 0.620). We suggest that PPARalpha activators may prevent the progression of myocarditis through increased expression of the gene encoding the anti-inflammatory cytokine IL-10, although the mechanisms involved remain to be determined.  相似文献   
124.
BACKGROUND/AIMS: Chemoprevention should be a promising approach to improve the prognosis of the patients with hepatocellular carcinoma (HCC). Angiogenesis is now recognized as a crucial step not only in tumor growth, but also in early carcinogenesis. The aim of this study was to elucidate the combination effect of the clinically used vitamin K(2) (VK) and the angiotensin-converting enzyme inhibitor, perindopril (PE), on hepatocarcinogenesis, especially in conjunction with angiogenesis. METHODS: In a diethylnitrosamine-induced rat hepatocarcinogenesis model, the effects of VK and PE on the development of liver enzyme-altered preneoplastic lesions and angiogenesis were examined. RESULTS: Treatment with both VK and PE markedly inhibited the development of preneoplastic lesions in association with suppression of neovascularization in the liver. The combination treatment with VK and PE exerted a more potent inhibitory effect as compared with the single agent treatments. The in vitro study demonstrated that VK and PE inhibited the endothelial cell (EC) tubular formation. VK also suppressed the EC proliferation in a dose-dependent manner. CONCLUSIONS: The combination of VK and PE exerted a chemopreventive effect against rat liver carcinogenesis via suppression of angiogenesis. Since both agents are widely used in the clinical practice, this combination therapy may represent a potential new strategy for chemoprevention against HCC in the future.  相似文献   
125.
126.
127.
128.
This study aimed to precisely discriminate Fasciola spp. based on DNA sequences of nuclear internal transcribed spacer 1 (ITS1) and mitochondrial nicotinamide adenine dinucleotide (NADH) dehydrogenase subunit 1 (nad1) gene. We collected 150 adult flukes from the bile ducts of cattle, buffaloes, sheep, and goats from six different regions of Bangladesh. Spermatogenic status was determined by analyzing stained seminal vesicles. The ITS1 types were analyzed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The nad1 haplotypes were identified based on PCR and direct sequencing and analyzed phylogenetically by comparing with nad1 haplotypes of Fasciola spp. from other Asian countries. Of the 127 aspermic flukes, 98 were identified as Fg type in ITS1, whereas 29 were identified as Fh/Fg type, indicating a combination of ITS1 sequences of Fasciola hepatica and Fasciola gigantica. All the 127 aspermic flukes showed Fsp-NDI-Bd11 in nad1 haplotype with nucleotide sequences identical to aspermic Fasciola sp. from Asian countries. Further, 20 spermic flukes were identified as F. gigantica based on their spermatogenic status and Fg type in ITS1. F. gigantica population was thought to be introduced into Bangladesh considerably earlier than the aspermic Fasciola sp. because 11 haplotypes with high haplotype diversity were detected from the F. gigantica population. However, three flukes from Bangladesh could not be precisely identified, because their spermatogenic status, ITS1 types, and nad1 haplotypes were ambiguous. Therefore, developing a robust method to distinguish aspermic Fasciola sp. from other Fasciola species is necessary in the future.  相似文献   
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