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   1298篇
  免费   109篇
  国内免费   11篇
耳鼻咽喉   16篇
儿科学   31篇
妇产科学   42篇
基础医学   173篇
口腔科学   28篇
临床医学   129篇
内科学   324篇
皮肤病学   25篇
神经病学   111篇
特种医学   30篇
外科学   172篇
综合类   27篇
一般理论   1篇
预防医学   54篇
眼科学   67篇
药学   98篇
中国医学   4篇
肿瘤学   86篇
  2024年   2篇
  2023年   14篇
  2022年   27篇
  2021年   54篇
  2020年   39篇
  2019年   57篇
  2018年   60篇
  2017年   41篇
  2016年   48篇
  2015年   43篇
  2014年   60篇
  2013年   70篇
  2012年   111篇
  2011年   122篇
  2010年   64篇
  2009年   49篇
  2008年   81篇
  2007年   82篇
  2006年   61篇
  2005年   65篇
  2004年   48篇
  2003年   51篇
  2002年   45篇
  2001年   17篇
  2000年   13篇
  1999年   15篇
  1998年   7篇
  1997年   7篇
  1996年   3篇
  1995年   4篇
  1993年   4篇
  1992年   4篇
  1991年   5篇
  1990年   6篇
  1989年   6篇
  1987年   3篇
  1986年   2篇
  1985年   4篇
  1984年   2篇
  1983年   3篇
  1982年   2篇
  1977年   2篇
  1976年   2篇
  1975年   1篇
  1974年   3篇
  1972年   1篇
  1971年   1篇
  1970年   1篇
  1969年   2篇
  1966年   1篇
排序方式: 共有1418条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
The present study was designed to compare the anatomical parameters of the cardiopulmonary system in three different lines of chickens with different susceptibility to ascites syndrome. Eggs from three different genetic lines-commercial broiler and layer lines and one native to Iran--were incubated and hatched, and 1-day-old chicks used. The relative heart and lung weights, the volumes of the heart, lung and thorax cavity, the incidence of ascites, and the related physiological parameters in these chickens were followed. Lung weight as a percentage of body weight, the relative lung and heart volume, and the volumes of the thorax cavity, before and after removing heart and lung tissues, were lower in fast-growing broiler chickens compared with the layer and native chickens. Additionally, most of these parameters (e.g. relative lung weight, lung volume and thorax cavity) were significantly decreased with age in broiler chickens but were increased in layer and native chickens, which was concomitant with the incidence of ascites in broiler chickens. Our data indicate that all cardiopulmonary parameters investigated are extremely unfavourable to broiler chickens and suggest a reduction in gas exchange area in broilers, and therefore higher susceptibility to pulmonary hypertension and ascites.  相似文献   
6.
We describe an outbreak, in a community of men who have sex with men, of serogroup C meningococcal disease caused by a genetic variant of the serotype 2a ET-15 Neisseria meningitidis characterized by a point mutation in the gene coding for the serotype 2a antigen. A microbiological characterization of the outbreak strain is presented in this report.  相似文献   
7.
Alternatively activated macrophages (aaMphi) display molecular and biological characteristics that differ from those of classically activated macrophages (caMphi). Recently, we described an experimental model of murine trypanosomosis in which the early stage of infection of mice with a Trypanosoma brucei brucei variant is characterized by the development of caMphi, whereas in the late and chronic stages of infection, aaMphi develop. In the present study, we used suppression subtractive hybridization (SSH) to identify genes that are expressed differentially in aaMphi versus caMphi elicited during infection with this T. b. brucei variant. We show that FIZZ1 and Ym1 are induced strongly in in vivo- and in vitro-elicited aaMphi as compared with caMphi. Furthermore, we demonstrate that the in vivo induction of FIZZ1 and Ym1 in macrophages depends on IL-4 and that in vitro, IFN-gamma antagonizes the effect of IL-4 on the expression of FIZZ1 and Ym1. Collectively, these results open perspectives for new insights into the functional properties of aaMphi and establish FIZZ1 and Ym1 as markers for aaMphi.  相似文献   
8.
Intermittent fasting and fasting mimetic diets ameliorate inflammation. Similarly, serum extracted from fasted healthy and asthmatic subjects’ blunt inflammation in vitro, implicating serum components in this immunomodulation. To identify the proteins orchestrating these effects, SOMAScan technology was employed to evaluate serum protein levels in healthy subjects following an overnight, 24-h fast and 3 h after refeeding. Partial least square discriminant analysis identified several serum proteins as potential candidates to confer feeding status immunomodulation. The characterization of recombinant IGFBP1 (elevated following 24 h of fasting) and PYY (elevated following refeeding) in primary human CD4+ T cells found that they blunted and induced immune activation, respectively. Furthermore, integrated univariate serum protein analysis compared to RNA-seq analysis from peripheral blood mononuclear cells identified the induction of IL1RL1 and MFGE8 levels in refeeding compared to the 24-h fasting in the same study. Subsequent quantitation of these candidate proteins in lean versus obese individuals identified an inverse regulation of serum levels in the fasted subjects compared to the obese subjects. In parallel, IL1RL1 and MFGE8 supplementation promoted increased CD4+ T responsiveness to T cell receptor activation. Together, these data show that caloric load-linked conditions evoke serological protein changes, which in turn confer biological effects on circulating CD4+ T cell immune responsiveness.  相似文献   
9.
Human Reproduction is a very complex and surprisingly inefficient process. The embryo development and the generation of a receptive endometrium needs an exact timing and synchronization. Understanding the factors involved in preimplantation embryo development and embryo-maternal interaction and implantation is crucial for improving success rates in reproductive medicine. The purpose of the present review is to describe briefly the function of adhesion- and hormonal factors, cytokines, growth factors and metalloproteinases. A better understanding of the molecular mechanisms of implantation will be responsible for the improvement of clinical and therapeutical management of sterility, infertility and contraception.  相似文献   
10.
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