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   31392篇
  免费   2056篇
  国内免费   225篇
耳鼻咽喉   464篇
儿科学   1322篇
妇产科学   1004篇
基础医学   4342篇
口腔科学   657篇
临床医学   3354篇
内科学   6398篇
皮肤病学   646篇
神经病学   2874篇
特种医学   1242篇
外国民族医学   14篇
外科学   5342篇
综合类   128篇
一般理论   3篇
预防医学   1671篇
眼科学   826篇
药学   1392篇
中国医学   19篇
肿瘤学   1975篇
  2023年   227篇
  2022年   232篇
  2021年   418篇
  2020年   331篇
  2019年   364篇
  2018年   537篇
  2017年   517篇
  2016年   666篇
  2015年   602篇
  2014年   859篇
  2013年   1111篇
  2012年   1264篇
  2011年   1359篇
  2010年   841篇
  2009年   1006篇
  2008年   1258篇
  2007年   1289篇
  2006年   1247篇
  2005年   1242篇
  2004年   1006篇
  2003年   1016篇
  2002年   935篇
  2001年   1004篇
  2000年   997篇
  1999年   916篇
  1998年   517篇
  1997年   465篇
  1996年   519篇
  1995年   456篇
  1994年   375篇
  1993年   293篇
  1992年   602篇
  1991年   641篇
  1990年   554篇
  1989年   533篇
  1988年   485篇
  1987年   480篇
  1986年   491篇
  1985年   471篇
  1984年   359篇
  1983年   285篇
  1982年   203篇
  1981年   205篇
  1980年   206篇
  1979年   299篇
  1978年   242篇
  1977年   197篇
  1975年   209篇
  1974年   221篇
  1973年   198篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
We report a case of a fatal toxic encephalomyelopathy in a 12-year-old girl due to prophylactic intrathecal injection of methotrexate and cytosine arabinoside, with a characteristic progressive symptomatology leading to death after 28 days. The location and type of neuropathological changes support the hypothesis of a direct toxic effect of methotrexate and/or cytosine arabinoside on structures directly exposed to the cerebrospinal fluid.  相似文献   
92.
Mice treated intraperitoneally with zymosan showed a strong inhibition of the DTHR (delayed-type hypersensitivity reaction) against sheep erythrocytes (SE), ovalbumin (OA), and alloantigen. Furthermore, the rejection time of skin transplants was nearly doubled while antibody formation against SE was significantly enhanced. When a DTHR against OA and an antibody formation against SE were induced at the same time in the same animals, than the suppressive and stimulating effects cancelled each other. These results are discussed with regard to the sensitivity of lymphocyte subpopulations, which may be different if exposed to phagocytosis-induced oxygen radicals.  相似文献   
93.
94.
The growth of a panel of eight different human glioblastoma cell lines was examined in a human tumor cloning assay in agar, a tritiated thymidine uptake assay, and by counting cell numbers, in cultures performed in the absence or presence of increasing concentrations (1 to 100 ng/ml) of recombinant human stem cell factor (SCF). Growth of 7 of 8 cell lines was not significantly and reproducibly affected by recombinant human SCF. However, growth of the CRL 1620 cell line could be stimulated up to 5-fold by the cytokine. In contrast to the other cell lines investigated, CRL 1620 expressed the c-kit protooncogene assessed on the mRNA and protein level. Furthermore, SCF-induced proliferation of CRL 1620 cells was sensitive to the tyrosine kinase inhibitor erbstatin. Our data suggest that SCF can be operative in growth modulation of malignant cells outside the hematopoietic system, and this finding should be further studied for its possible clinical implications.  相似文献   
95.
96.
A survey by questionnaire was carried out to examine the level of nursing staff satisfaction with the acute psychiatric services. Comparisons were made between views of older psychiatric hospitals and newer district general hospital units, and before and after the closure of Friern Barnet Hospital, London, England when the service was reorganized to include fewer beds. The importance of nurses having their say is emphasized, and areas in which improvements can be made are suggested.  相似文献   
97.
Crohn's disease is a complex disorder, with multiple genetic traits. A frameshift mutation (Leu1007fsinsC) and two missense mutations (Gly908Arg and Arg702Trp) in the NOD2/CARD15 gene are strongly associated with susceptibility to Crohn's disease. The presence of one of these risk alleles confers a 2- to 4-fold increase in the risk of developing Crohn's disease, and the presence of two mutant alleles increases the risk over 20-fold. To facilitate the analysis of these polymorphisms, we developed three LightCycler assays to detect the missense mutations Arg702Trp and Gly908Arg and the frameshift mutation Leu100fsinsC in the NOD2/ CARD15 gene. All three assays can be run simultaneously on one LightCycler using identical cycling parameters. Analysis of 53 DNAs from Crohn's patients helped to identify carriers at allele frequencies similar to other Caucasian populations. The sequencing of such DNAs confirmed the accuracy of the assays. In conclusion, we present three rapid and robust assays to detect the Arg702Trp, the Gly908Arg and the Leu1007fsinsC ins mutations in the NOD2/CARD15 gene [corrected]  相似文献   
98.
99.
Concentrations of the serotonin metabolite 5-hydroxyindole acetic acid (5-HIAA), the dopamine metabolite homovanillic acid (HVA) and the noradrenaline metabolite 4-hydroxy-3-methoxyphenyl glycol (HMPG) were determined in urine samples from healthy male and female students by mass fragmentography. Urine samples were obtained after a demanding examination (mental stress) and a day of ordinary school work (control condition). Self-ratings were obtained of feelings induced by the examination, and of habitual psychosomatic symptoms. The results for both sexes showed that the examination stress induced a significant increase of HVA and HMPG excretion, but not of 5-HIAA. The males excreted significantly more of each of the metabolites than the females. The pattern of correlations between metabolite levels and psychological and psychosomatic variables were strikingly different for the two sexes.  相似文献   
100.
ELISA-based epitope analysis was performed using rabbit polyclonal antisera against melittin. Antigenic sites were found at the C-terminus, in the middle section and within the N-terminal helix. Antibodies against the helical segment could discriminate between two faces of the amphiphilic helix. The antigenic sites include the bulk of the melittin hexacosapeptide, which is synonymous with a very high epitope density.  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