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   372137篇
  免费   286532篇
  国内免费   44148篇
耳鼻咽喉   3560篇
儿科学   5347篇
妇产科学   3595篇
基础医学   103357篇
口腔科学   4772篇
临床医学   75556篇
内科学   111249篇
皮肤病学   6266篇
神经病学   27900篇
特种医学   13600篇
外国民族医学   89篇
外科学   53252篇
综合类   73840篇
现状与发展   31篇
一般理论   8篇
预防医学   49855篇
眼科学   21236篇
药学   71271篇
  150篇
中国医学   53194篇
肿瘤学   24689篇
  2022年   8726篇
  2021年   10559篇
  2020年   11108篇
  2019年   17203篇
  2018年   18132篇
  2017年   18372篇
  2016年   16795篇
  2015年   18900篇
  2014年   20068篇
  2013年   19174篇
  2012年   22920篇
  2011年   25107篇
  2010年   23333篇
  2009年   29891篇
  2008年   18872篇
  2007年   15263篇
  2006年   14388篇
  2005年   14054篇
  2004年   13981篇
  2003年   12797篇
  2002年   12507篇
  2001年   13847篇
  2000年   9533篇
  1999年   14740篇
  1998年   15211篇
  1997年   15087篇
  1996年   15810篇
  1995年   15897篇
  1994年   15487篇
  1993年   13953篇
  1992年   13428篇
  1991年   12653篇
  1990年   11580篇
  1989年   11342篇
  1988年   10849篇
  1987年   10139篇
  1986年   9624篇
  1985年   8657篇
  1984年   6633篇
  1983年   6634篇
  1982年   7645篇
  1981年   7180篇
  1980年   6824篇
  1979年   6679篇
  1978年   5831篇
  1977年   6128篇
  1976年   5751篇
  1975年   5487篇
  1974年   5047篇
  1973年   4768篇
排序方式: 共有10000条查询结果,搜索用时 25 毫秒
51.
52.
In vitro studies established that neither cloth nor disposable diapers demonstrably contributed to the growth of Escherichia coli, Proteus vulgaris, Staphylococcus aureus, or Candida albicans when urine was present as a growth medium. In a clinical study of 166 children, the microbial skin flora of children with atopic dermatitis was compared with the flora of children with normal skin to determine the influence of diaper type. No biologically significant differences were detected between groups wearing disposable or cloth diapers in terms of frequency of isolation or log mean recovery of selected skin flora. Repeated isolation of S. aureus correlated with atopic dermatitis. The log mean recovery of S. aureus was higher in the atopic groups. The effects of each diaper type on skin microflora were equivalent in the normal and atopic populations.  相似文献   
53.
Wir berichten über den ersten Fall von polyzystischer lipomembran?ser Osteodysplasie oder “brain, bone and fat disease” in Deutschland. Die nach dem Erstbeschreibern auch als Morbus J?rvi-Hakola-Nasu bezeichnete Erkrankung ist bisher vor allem in Japan und in Finnland beschrieben worden. Einzelne F?lle wurden aus Schweden, Norwegen, Italien, Südafrika, Belgien und den USA berichtet. Im deutschsprachigen Raum ist bisher ein Fall aus ? ver?ffentlicht worden.  相似文献   
54.
55.
56.
57.
Galanin-like immunoreactivity has been visualized in nerve fibers in the islets of Langerhans, suggesting an involvement of galanin in the neural regulation of islet function. In this study, we investigated the effects of galanin on basal and stimulated insulin and glucagon secretion by infusing the peptide at three different dose rates in rats. We also studied the direct effect of galanin on insulin secretion from freshly isolated rat islets. At 320 pmol/kg/min, but not at 20 or 80 pmol/kg/min, galanin lowered basal plasma insulin levels. In contrast, basal plasma glucagon levels were lowered by galanin already at 20 and 80 pmol/kg/min. Furthermore, galanin inhibited both glucose- and arginine-induced insulin release at all three dose levels, whereas arginine-induced glucagon release was not affected by galanin. Glucose-stimulated insulin secretion from isolated rat islets was dose-dependently suppressed by galanin (10-6-10-8M). Therefore, it is concluded that galanin in rats inhibits insulin secretion, both in vivo and in vitro, and that at lower dose levels, the peptide also inhibits basal glucagon release.  相似文献   
58.
The effects of different amounts of dietary zinc on the Zn absorption rate and on Zn, calcium and magnesium concentrations in tissues of MOPC 104E tumor-bearing Balb/c mice were determined. The Zn absorption rate was inversely related to the amounts of Zn in their diets and was lower than that of nontumor-bearing control mice fed a laboratory mice chow. Zn concentrations of tumor-bearing mice were also low compared with control mice but tumor Zn concentrations, regardless of the concentrations of Zn in the diets, were higher than those of normal tissues of the host other than the pancreas. Ca concentrations in tumor and tissues of tumor-bearing mice were higher than in control animals but Mg concentrations in tissues of tumor-bearing mice appeared to be similar to those of control mice. Results suggest that tumor-bearing mice have a lower intestinal Zn absorption capacity and a higher Zn uptake rate causing other tissues to become hypozincemic and hypercalcemic.  相似文献   
59.
1. Postmortem neurochemical investigations revealed interhemispheric asymmetry in the mediofrontal region of human brain. Significantly higher right hemisphere serotonin metabolite (5HIAA) content as well as increased maximal imipramine binding (IB) were found in the right hemisphere than in the left side.

2. IB did not show a gender difference in the mediofrontal area. However, women had higher IB in the right orbital frontal cortex than did men.

3. In vivo pharmaco-EEG results tend to support the postmortem neurochemical data. Intravenous chlorimipramine resulted in an asymmetric topographic distribution of the P300 auditory evoked potential, peak amplitudes were shifted to the right hemisphere.  相似文献   

60.
In order to clarify the reported discrepancies in S100 alpha protein and mRNA distribution in rat tissues, a rat S100 alpha cDNA has been isolated and this species homologous probe along with a rat S100 beta cDNA probe has been used to examine S100 mRNA expression in rat tissues. Although the rat S100 alpha cDNA was missing approximately 30 nucleotides of coding sequence, only 4 conservative changes in amino acid sequence were observed when the deduced amino acid sequence was compared to the bovine S100 alpha amino acid sequence. Thus, S100 alpha proteins, like S100 beta proteins, are highly conserved among species. All nineteen of the tissues examined (including cerebrum and cerebellum) contained S100 alpha mRNA. In addition, S100 beta mRNA was detected in thirteen of the nineteen tissues examined. These results are in agreement with previous protein distribution studies and further demonstrate that S100 proteins are not brain-specific and are expressed in a large number of tissues. Although S100 alpha and S100 beta mRNAs were detected in rat tissues which had previously been reported to contain S100 alpha and S100 beta protein, a direct correlation between the protein and mRNA levels were not observed, suggesting that different mechanisms regulate S100 expression in various tissues. S100 alpha exhibited a single similar size mRNA species (0.5 Kb) in all tissues examined, as did S100 beta (1.5 Kb), suggesting that the individual S100 proteins are expressed as single mRNA and protein products in rat tissues.  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