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   9818篇
  免费   777篇
  国内免费   33篇
耳鼻咽喉   51篇
儿科学   204篇
妇产科学   126篇
基础医学   1433篇
口腔科学   69篇
临床医学   1086篇
内科学   2638篇
皮肤病学   171篇
神经病学   791篇
特种医学   415篇
外国民族医学   1篇
外科学   1462篇
综合类   21篇
一般理论   1篇
预防医学   530篇
眼科学   187篇
药学   717篇
中国医学   23篇
肿瘤学   702篇
  2024年   5篇
  2023年   57篇
  2022年   105篇
  2021年   286篇
  2020年   150篇
  2019年   278篇
  2018年   306篇
  2017年   218篇
  2016年   241篇
  2015年   293篇
  2014年   406篇
  2013年   508篇
  2012年   893篇
  2011年   904篇
  2010年   476篇
  2009年   402篇
  2008年   692篇
  2007年   672篇
  2006年   698篇
  2005年   644篇
  2004年   607篇
  2003年   566篇
  2002年   488篇
  2001年   74篇
  2000年   55篇
  1999年   81篇
  1998年   101篇
  1997年   64篇
  1996年   44篇
  1995年   34篇
  1994年   40篇
  1993年   33篇
  1992年   32篇
  1991年   20篇
  1990年   19篇
  1989年   17篇
  1988年   15篇
  1987年   11篇
  1986年   12篇
  1985年   13篇
  1984年   7篇
  1983年   9篇
  1982年   5篇
  1981年   7篇
  1980年   6篇
  1979年   4篇
  1978年   5篇
  1974年   4篇
  1972年   3篇
  1971年   5篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Epoxide hydrolases play an important role in detoxifying epoxides that arise from the metabolism of xenobiotic and endogenous compounds. Both the soluble and microsomal forms of epoxide hydrolase (sEH and mEH, respectively) have been detected in the rat testis. Because of the important role the epididymis plays in sperm maturation and protection, the present study evaluated the presence and activity of these two epoxide hydrolases in the rat epididymis. Using Western blotting, protein bands consistent in size with both mEH and sEH were detected in the caput, corpus, and cauda of the epididymis. The mEH immunoreactive bands in the epididymis ( approximately 50 kDa) were consistent with mEH detected in the liver and kidney. The sEH immunoreactive bands in the epididymis ( approximately 65 kDa) were consistent with a recombinant sEH standard and sEH detected in the liver, kidney, and testis. The presence of mEH and sEH in the epididymis was supported by observations from substrate-based enzyme assays. Results indicated that epididymal mEH can hydrolyze [(3)H]-cis-stilbene oxide to the corresponding diol at levels approximately 9% of the kidney. Epididymal sEH hydrolyzed the substrate [(3)H]-trans-diphenylpropene oxide to the corresponding diol and this activity was inhibited by cyclohexyl-dodecyl urea. Arachidonic acid epoxygenase activity was detected in epididymal S9 fractions, suggesting that fatty acid metabolism by epididymal cytochrome P450s can form epoxides that subsequently become substrates for epididymal sEH. Results from the present study indicate that the epididymis contains at least two active forms of epoxide hydrolase. The role of these enzymes in the detoxification of xenobiotic epoxides is well known, although it is unclear what cellular role they may play in the formation of biologically active metabolites in the epididymis.  相似文献   
102.
103.
104.
105.
BackgroundTreatment of tailor's bunion is largely conservative. For severe or refractory cases surgical intervention is necessary. The aim of this study is to evaluate a percutaneous technique for correcting such bunionette deformities.MethodsTwenty-one procedures were performed on 20 patients using a percutaneous technique. Patients were scored using the American Orthopaedic Foot & Ankle Society (AOFAS) Lesser Toe Metatarsophalangeal–Interphalangeal Scale.ResultsNo wound healing problems, infections, non-unions or mal-unions occurred. Functional assessments revealed very good results. Radiographic evaluation confirmed good average correction of the fourth–fifth intermetatarsal angle and metatarsophalangeal angle.ConclusionsThis percutaneous technique is a reliable and effective approach for the treatment of bunionette deformity. The results obtained were comparable to those reported using traditional open techniques, but major complications due to soft tissue damage were averted. This technique can be adapted depending on the type of deformity, and does not require internal fixation.  相似文献   
106.
The levels of fumonisins (FUMO)—mycotoxins produced by Fusarium verticillioides—in maize for food and feed are subject to European Union regulations. Compliance with the regulations requires the targeting of, among others, the agroclimatic factors influencing fungal contamination and FUMO production. Arvalis-Institut du végétal has created a national, multiyear database for maize, based on field survey data collected since 2003. This database contains information about agricultural practices, climatic conditions and FUMO concentrations at harvest for 738 maize fields distributed throughout French maize-growing regions. A linear mixed model approach highlights the presence of borers and the use of a late variety, high temperatures in July and October, and a water deficit during the maize cycle as creating conditions favoring maize contamination with Fusarium verticillioides. It is thus possible to target a combination of risk factors, consisting of this climatic sequence associated with agricultural practices of interest. The effects of the various possible agroclimatic combinations can be compared, grouped and classified as promoting very low to high FUMO concentrations, possibly exceeding the regulatory threshold. These findings should facilitate the creation of a national, informative and easy-to-use prevention tool for producers and agricultural cooperatives to manage the sanitary quality of their harvest.  相似文献   
107.
To use mesoporous silicas as low-k materials, the pore entrances must be really small to avoid diffusion of metals that can increase the dielectric constant of the low-k dielectric. In this paper we present a new method to narrow the pores of mesoporous materials through grafting of a cyclic-bridged organosilane precursor. As mesoporous material, the well-studied MCM-41 powder was selected to allow an easy characterization of the grafting reactions. Firstly, the successful grafting of the cyclic-bridged organosilane precursor on MCM-41 is presented. Secondly, it is demonstrated that pore narrowing can be obtained without losing porosity by removing the porogen template after grafting. The remaining silanols in the pores can then be end-capped with hexamethyl disilazane (HMDS) to make the material completely hydrophobic. Finally, we applied the pore narrowing method on organosilica films to prove that this method is also successful on existing low-k materials.  相似文献   
108.
109.
110.
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