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   845篇
  免费   71篇
  国内免费   22篇
耳鼻咽喉   6篇
儿科学   68篇
妇产科学   9篇
基础医学   109篇
口腔科学   43篇
临床医学   67篇
内科学   147篇
皮肤病学   27篇
神经病学   19篇
特种医学   218篇
外科学   67篇
综合类   35篇
预防医学   50篇
眼科学   6篇
药学   24篇
肿瘤学   43篇
  2021年   4篇
  2019年   6篇
  2018年   8篇
  2017年   9篇
  2016年   8篇
  2015年   8篇
  2014年   15篇
  2013年   13篇
  2012年   8篇
  2011年   15篇
  2010年   24篇
  2009年   24篇
  2008年   24篇
  2007年   20篇
  2006年   25篇
  2005年   24篇
  2004年   16篇
  2003年   22篇
  2002年   11篇
  2001年   16篇
  2000年   23篇
  1999年   18篇
  1998年   43篇
  1997年   45篇
  1996年   42篇
  1995年   36篇
  1994年   23篇
  1993年   31篇
  1992年   21篇
  1991年   18篇
  1990年   17篇
  1989年   24篇
  1988年   30篇
  1987年   44篇
  1986年   27篇
  1985年   18篇
  1984年   9篇
  1983年   13篇
  1982年   15篇
  1981年   20篇
  1980年   18篇
  1979年   8篇
  1978年   7篇
  1977年   10篇
  1976年   21篇
  1975年   10篇
  1934年   4篇
  1930年   3篇
  1927年   4篇
  1926年   4篇
排序方式: 共有938条查询结果,搜索用时 15 毫秒
11.
The present study was undertaken to assess the temporal association between the profiles of serum concentrations of oestradiol-17beta, progesterone, chorionic gonadotrophin (CG) and relaxin in pregnancies established naturally, and after embryo transfer, as well as in failed pregnancies in rhesus monkeys. In naturally mated cycles (group 1) a conception rate of 75% was obtained. In group 1, the mean day of CG detection in serum was 11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day post-ovulation. In group 2, embryo transfer to synchronous, non-mated surrogate recipients was performed; seven embryo transfer cycles yielded three pregnancies which were allowed to continue to term and normal infants were delivered. In embryo transfer cycles the mean day of CG detection was 14.8 +/- 1.8 day post- ovulation, and for relaxin, 11.4 +/- 2.6 day post-ovulation. A delay of about 3 days was observed in the appearance in circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between natural mated and embryo transfer conception cycles. Significant differences (P < 0.05 for progesterone and P < 0.03 for oestradiol) were obtained for the areas under the curves for progesterone and oestradiol between days 12 and 16 in conception cycles compared with failed pregnancies. These data provide the first observation of the normal hormonal signals associated with maternal recognition of transferred embryos during the peri- implantation period, and suggest that the use of such an experimental primate embryo transfer model may help to elucidate components of maternal and embryonic signal-response mechanisms during embryo implantation.   相似文献   
12.
Multiple sclerosis (MS) is a demyelinating autoimmune disease of the central nervous system. While its etiology is not well understood, genetic factors are clearly involved. Until recently, most genetic studies in MS have been association studies using the case-control design testing specific candidate genes and studying only sporadic cases. The only consistently replicated finding has been an association with the HLA-DR2 allele within the major histocompatibility complex (MHC) on chromosome 6. Using the genetic linkage design, however, evidence for and against linkage of the MHC to MS has been found, fostering suggestions that sporadic and familial MS have different etiologies. Most recently, two of four genomic screens demonstrated linkage to the MHC, although specific allelic associations were not tested. Here, a dataset of 98 multiplex families was studied to test for an association to the HLA-DR2 allele in familial MS and to determine if genetic linkage to the MHC was due solely to such an association. Three highly polymorphic markers (HLA-DR, D6S273 and TNFbeta) in the MHC demonstrated strong genetic linkage (parametric lod scores of 4.60, 2.20 and 1.24, respectively) and a specific association with the HLA-DR2 allele was confirmed (TDT; P < 0.001). Stratifying the results by HLA-DR2 status showed that the linkage results were limited to families segregating HLA-DR2 alleles. These results demonstrate that genetic linkage to the MHC can be explained by the HLA-DR2 allelic association. They also indicate that sporadic and familial MS share a common genetic susceptibility. In addition, preliminary calculations suggest that the MHC explains between 17 and 62% of the genetic etiology of MS. This heterogeneity is also supported by the minority of families showing no linkage or association with loci within the MHC.   相似文献   
13.
Currently, antiretroviral therapy has become more affordable even in developing countries and it is being used in India. Fifteen HIV-1 infected individuals, who were on highly active antiretroviral therapy (HAART), were followed up for an average period of one year. The plasma viral load and CD4+ T cell estimation done at mean intervals of 5 months and 11 months after initiation of therapy showed a good response to therapy in 14 (93%) individuals.  相似文献   
14.
The performance of a rapid particle agglutination test for human immunodeficiency virus (HIV) (Capillus HIV type 1 [HIV-1]/HIV-2) on hospital samples is compared with enzyme-linked immunosorbent assays. The test had a sensitivity and specificity of 99 and 98.9%, respectively. In addition, the test was reactive on plasma samples from all individuals infected with HIV-1 subtype C. This test can safely be used for voluntary counseling and testing in India.  相似文献   
15.
The intercellular adhesion molecule (ICAM) family of proteins   总被引:8,自引:0,他引:8  
Macromolecular adhesive associations between cells are important for transmitting spatial and temporal information that is critical for immune system function. One such group of proteins, the intercellular adhesion molecules (ICAMs), has grown as newly identified members are revealed. In addition, the functions of the ICAMs, in general, have begun to be better understood, including intracellular signaling events. This information has led to the design of novel therapeutic agents that may prove effective in a variety of disease states.  相似文献   
16.
A coagglutination procedure for detecting Vibrio cholerae was applied directly to 125 watery fecal samples received in the laboratory for bacteriological culture: many of these were from suspected cases of cholera. Of 47 bacteriologically proved cases of cholera, 44 (93.6%) gave positive results by the coagglutination method. There was a good correlation between the coagglutination method, dark-field microscopy, and culture.  相似文献   
17.
18.
19.
20.
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