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   619篇
  免费   45篇
  国内免费   12篇
耳鼻咽喉   42篇
儿科学   34篇
妇产科学   8篇
基础医学   64篇
口腔科学   53篇
临床医学   58篇
内科学   112篇
皮肤病学   7篇
神经病学   56篇
特种医学   65篇
外科学   68篇
综合类   12篇
预防医学   27篇
眼科学   5篇
药学   31篇
肿瘤学   34篇
  2023年   5篇
  2022年   2篇
  2021年   17篇
  2020年   10篇
  2019年   16篇
  2018年   16篇
  2017年   9篇
  2016年   11篇
  2015年   15篇
  2014年   24篇
  2013年   25篇
  2012年   34篇
  2011年   40篇
  2010年   30篇
  2009年   36篇
  2008年   29篇
  2007年   42篇
  2006年   29篇
  2005年   30篇
  2004年   20篇
  2003年   18篇
  2002年   13篇
  2001年   18篇
  2000年   6篇
  1999年   3篇
  1998年   18篇
  1997年   12篇
  1996年   13篇
  1995年   10篇
  1994年   12篇
  1993年   5篇
  1992年   5篇
  1991年   3篇
  1990年   4篇
  1989年   7篇
  1988年   5篇
  1987年   10篇
  1986年   10篇
  1985年   5篇
  1984年   4篇
  1983年   2篇
  1982年   5篇
  1981年   9篇
  1980年   7篇
  1979年   5篇
  1978年   4篇
  1977年   3篇
  1976年   6篇
  1968年   3篇
  1942年   2篇
排序方式: 共有676条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
Administration of supraphysiological doses of testosterone to normal men causes inhibition of spermatogenesis, but while most become azoospermic, 30-55% maintain a low rate of spermatogenesis. We have investigated whether there are differences in endogenous androgen production, of testicular and adrenal origin, which may be related to the degree of suppression of spermatogenesis. Thirty-three healthy Caucasian men were given weekly i.m. injections of 200 mg testosterone oenanthate (TE), 18 became azoospermic, while 15 remained oligozoospermic. Urinary excretion of epitestosterone, a specific testicular product, was reduced to <10% of pretreatment values, with no differences between the groups. Similar results were obtained for other markers of testicular steroidogenesis. Urinary and plasma adrenal androgens were also reduced during TE treatment: a statistically significant decrease in both (P < 0.001 and P < 0.05 respectively) was seen in the azoospermic but not oligozoospermic responders. These results suggest that testicular steroidogenesis is decreased to <10% by the administration of supraphysiological doses of exogenous testosterone. Differences in the degree of ongoing steroidogenesis in the testis do not appear to account for incomplete suppression of spermatogenesis, thus differences in androgen metabolism may underlie this heterogeneous response. A small but significant reduction in secretion of adrenal androgens was also detectable, the relevance of which is unclear.   相似文献   
5.
Monette  FC; Holden  SA 《Blood》1982,60(2):527-530
Since exogenous hemin has been shown to exert a variety of stimulatory effects on erythroid cells, including the augmentation of hemoglobin synthesis, we determined its effect on early stages of erythroid development by employing clonal cells assays. The addition of hemin at a concentration of 2 X 10(-4) M to cultures of normal murine marrow substantially increased the observed number of primitive BFU-E, which was in contrast to its lack of an effect on more mature erythroid colony-forming cells. This cell-specific enhancement of primitive BFU-E resulted in marrow frequencies equivalent to or exceeding those reported in the presence of "burst-promoting activity." In the presence of hemin, the number of BFU-E was also observed to be linearly related to the number of cells plated at very low plating densities, and the cell titration curve was observed to extrapolate to the origin. The evidence suggests that hemin may be a primary growth regulator of early developmental stages of erythroid progenitor cells.  相似文献   
6.
7.
Metastastic tumours involving the epididymis are rare and most often found in patients with disseminated disease. It is even more unusual when the metastasis of the epididymis is the first sign of tumour recurrence. We report a case of an asymptomatic recurrent colon carcinoma presenting as metastasis in the epididymis. Although metastatic cancer presenting as an intra-scrotal mass is extremely rare, it should be considered as a possibility in patients who present with a mass involving the testicle or epididymis.  相似文献   
8.
Malignant triton tumor (MTT) is an aggressive peripheral nerve sheath tumor with rhabdomyoblastic differentiation. Less than 100 cases have been described, being mostly male children with type 1 neurofibromatosis. We report a 6‐year‐old female with MTT and no diagnostic criteria for neurofibromatosis type 1. Cytogenetic analysis showed a 46,X,‐X[4]/46,XX[16] karyotype. She underwent a transfemoral amputation and chemotherapy and is free of disease 15 months after diagnosis. The few cytogenetic studies of MTT described in the literature have been inconclusive. Further cytogenetic analyses are needed to understand the role of chromosome X monosomy in the pathogenesis of this rare tumor. Pediatr Blood Cancer 2012; 59: 1320–1323. © 2012 Wiley Periodicals, Inc.  相似文献   
9.
10.
Journal of NeuroVirology - We describe two neurological cases of Oropouche virus infection in northern Brazil, where the virus is endemic but neglected as a pathogen. This study reiterates the...  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