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   15656篇
  免费   1217篇
  国内免费   116篇
耳鼻咽喉   124篇
儿科学   494篇
妇产科学   362篇
基础医学   2168篇
口腔科学   407篇
临床医学   1710篇
内科学   3353篇
皮肤病学   316篇
神经病学   1081篇
特种医学   1023篇
外国民族医学   17篇
外科学   1895篇
综合类   174篇
一般理论   6篇
预防医学   1386篇
眼科学   195篇
药学   1005篇
  2篇
中国医学   20篇
肿瘤学   1251篇
  2021年   180篇
  2020年   140篇
  2019年   206篇
  2018年   283篇
  2017年   178篇
  2016年   256篇
  2015年   293篇
  2014年   374篇
  2013年   505篇
  2012年   656篇
  2011年   648篇
  2010年   436篇
  2009年   439篇
  2008年   634篇
  2007年   666篇
  2006年   630篇
  2005年   606篇
  2004年   562篇
  2003年   566篇
  2002年   546篇
  2001年   543篇
  2000年   574篇
  1999年   513篇
  1998年   316篇
  1997年   310篇
  1996年   283篇
  1995年   236篇
  1994年   226篇
  1993年   211篇
  1992年   385篇
  1991年   342篇
  1990年   329篇
  1989年   308篇
  1988年   312篇
  1987年   267篇
  1986年   304篇
  1985年   275篇
  1984年   212篇
  1983年   187篇
  1982年   120篇
  1981年   122篇
  1980年   124篇
  1979年   155篇
  1978年   119篇
  1977年   113篇
  1976年   101篇
  1975年   99篇
  1974年   105篇
  1973年   116篇
  1971年   86篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
(1) Liver cirrhosis was induced in male rats by treatment with carbon tetrachloride and phenobarbitone for 130-142 days. Detailed histological examination showed all livers from rats treated with carbon tetrachloride had annular fibrosis, necrosis, loss of normal hepatic architecture and other features that were consistent with an established micronodular cirrhosis. (2) Plasma biochemical analysis showed a significant reduction in total protein concentration (13%), which was due entirely to a reduction in plasma albumin (29%). There were also large increases in the plasma activities of alkaline phosphatase (110%) and aspartate aminotransferase (159%), when compared to phenobarbitone-treated controls. Plasma cholesterol was also increased (67%), but other plasma analytes were not significantly altered. (3) The soleus (Type I), plantaris (Type II) and gastrocnemius (Types I and II) muscles were dissected and examined for possible differential effects. There were minor reductions in all three muscle weights, but these changes did not reach statistical significance. The protein, RNA and DNA concentrations, total muscle content and content relative to body weight in cirrhotic rats were also not significantly altered in any of the muscles. Cirrhosis did not cause any perturbations in derived parameters, i.e. amount of synthetic apparatus per cell, RNA/DNA ratio, apparent cell size, protein/DNA ratio and the capacity for protein synthesis or RNA/protein ratio. (4) The gastrocnemius was fractionated into soluble, stromal and myofibrillar proteins. The concentrations and contents of all three proteins were unaltered in cirrhotic animals, compared to controls. (5) It is concluded that in this experimental model of cirrhosis there were no effects on those skeletal muscle variables which are strikingly altered by chronic alcohol feeding.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
22.
Comment     
  相似文献   
23.
In order to identify risk factors for preterm birth in singletons, data from a population-based case control survey on the island of Curacao were re-analysed. Both medical and sociodemographic variables were examined. Overall, a history of previous preterm birth and severe hypertension during the index pregnancy were indicators of adverse pregnancy outcome, in terms of preterm birth. The contribution of sociodemographic factors to the risk of preterm birth is relatively low.  相似文献   
24.
25.
26.
27.
28.
Invasive pulmonary aspergillosis is characterized by radiological signs allowing a correct diagnosis, including differentiation from pulmonary candidiasis, when they are associated with appropriate clinical symptoms (neutropenia and fever persisting despite broad-spectrum antibiotics). In particular the formation of a pulmonary mycetoma in a previously normal lung is one of these signs. Unlike a simple fungus ball (the saprophytic form of aspergillosis), the rounded density of invasive pulmonary aspergillosis consists of sequestrum of devitalized lung tissue owing to blood vessel invasion by Aspergillus hyphae. This morphologic phenomenon is demonstrated in the present case report and is discussed together with the other roentgenological signs of the invasive aspergillosis.  相似文献   
29.
The effect of valproic acid on the distribution of gavaged 65Zn in maternal and embryonic tissue of Sprague-Dawley rats was examined 24 h after gavaging of the drug on d 13 of pregnancy. Valproic acid treatment resulted in a significantly higher retention of 65Zn in maternal liver and lower amounts in uterus, placenta and embryos than in controls. Compared to controls, gel chromatography of maternal liver from valproic acid-treated dams showed higher 65Zn counts associated with a protein peak of molecular weight of 6,500, the approximate molecular weight of the Zn-binding protein metallothionein. These results support the idea that the teratogenicity of valproic acid is in part due to an induction of embryonic Zn deficiency secondary to a drug-induced sequestering of Zn into maternal liver that results in a decrease in maternal plasma Zn and subsequent reduction in embryonic Zn uptake.  相似文献   
30.
Polymer-associated infection is a problem of increasing importance in modern medicine. In a new approach to prevent such infections we have modified polyvinylfluoride (TEDLAR) films by graft copolymerization with N-vinylpyrrolidone to which iodine can be complexed. Grafting reaction was performed by the preirradiation technique using an electron accelerator. Grafted films were then treated in Lugol's solution for at least 24 h. Release of free iodine from the films was determined either by titration or using the agar disc diffusion test, showing an iodine release for up to 4-5 days. The antimicrobial activity of the films was tested in bacterial adhesion measurements. Bacterial and fungal cells in the range of 10(3) to 10(6) cfu/cm2 polymer were found on control samples without iodine, whereas on iodine-complexed films no viable cells could be detected at least for 5 days or even longer. Thus, microbial adhesion and growth can be inhibited by iodine-containing polymers.  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