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   15640篇
  免费   1211篇
  国内免费   37篇
耳鼻咽喉   298篇
儿科学   321篇
妇产科学   214篇
基础医学   2049篇
口腔科学   520篇
临床医学   1492篇
内科学   3206篇
皮肤病学   202篇
神经病学   1723篇
特种医学   549篇
外科学   2209篇
综合类   243篇
一般理论   10篇
预防医学   1409篇
眼科学   265篇
药学   1043篇
  1篇
中国医学   9篇
肿瘤学   1125篇
  2023年   89篇
  2022年   145篇
  2021年   272篇
  2020年   201篇
  2019年   227篇
  2018年   297篇
  2017年   231篇
  2016年   241篇
  2015年   241篇
  2014年   388篇
  2013年   670篇
  2012年   878篇
  2011年   946篇
  2010年   568篇
  2009年   567篇
  2008年   963篇
  2007年   996篇
  2006年   1048篇
  2005年   998篇
  2004年   980篇
  2003年   987篇
  2002年   969篇
  2001年   174篇
  2000年   111篇
  1999年   151篇
  1998年   215篇
  1997年   197篇
  1996年   196篇
  1995年   163篇
  1994年   139篇
  1993年   107篇
  1992年   118篇
  1991年   109篇
  1990年   105篇
  1989年   74篇
  1988年   92篇
  1987年   83篇
  1986年   91篇
  1985年   97篇
  1984年   124篇
  1983年   137篇
  1982年   161篇
  1981年   140篇
  1980年   153篇
  1979年   72篇
  1978年   114篇
  1977年   91篇
  1976年   96篇
  1974年   71篇
  1972年   60篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
63.
Samples taken from an activated sludge reactor used for the biodegradation of metal cutting fluids were studied for the presence of plasmid-containing bacteria. Twenty different bacterial isolates contained one or more plasmids. After numerous transfers of the isolates through LB broth, 55% of the plasmids were spontaneously lost as evidenced by agarose gel electrophoresis. Eighty percent of the isolates were resistant to one or more antibiotics, 65% resistant to two or more antibiotics, 40% resistant to three or more, 20% resistant to four or more and 5% resistant to five antibiotics. The isolates were also tested for their sensitivity to several common metals. This study has demonstrated that activated sludge is a natural reservoir for plasmid-containing bacteria involved in biodegradation of wastes.  相似文献   
64.
65.
66.
67.
A pilot study was conducted of the biological characteristics of the leukemia cells of newly diagnosed patients with poor prognosis acute myelogenous leukemia (AML). This study included measurements of the pretherapy proliferative rate of the leukemia cells in vivo, assessment of differentiation in vivo during remission induction therapy, and the level of expression of the fms, myc, and IL1β genes in pretherapy leukemia cells. Short cell cycle times were characteristic of the best prognostic category and were associated with a rapid reduction in marrow leukemia cells in cytosine arabinoside (araC)-sensitive patients. Expression of c-fms was associated with rapid reduction in marrow leukemia cells during araC therapy and with a successful treatment outcome. Expression of the IL1β gene was associated with short remissions. These studies suggest that when compared to newly diagnosed standard prognosis AML, the leukemia of poor prognosis patients is more likely to exhibit long cell cycle times, low levels of fms expression, and is less likely to be associated with myeloid differentiation during remission induction therapy. © 1993 Wiley-Liss, Inc.  相似文献   
68.
Surgical rejuvenation of the upper face involves the correction of excess and lax forehead, eyelid, and periorbital skin. Improving the appearance by correcting the effects of aging involves a combination of blepharoplasty and open coronal foreheadplasty. Many surgeons and several reports question the safety of both procedures being performed concomitantly. The difficulty arises in precisely balancing the skin excision from the frontal forehead and upper eyelid areas. Over-resection of skin may result in incomplete closure of the eyelid and dry-eye syndrome, while an inadequate resection may produce a poor aesthetic result. There is no large series that documents the safety and effectiveness of these two procedures being performed concomitantly. Furthermore, with the recent and rapid development of complex multiplanar endoscopic facial rejuvenation techniques, the basic open forehead-plasty has become increasingly overlooked as a legitimate, efficacious technique for rejuvenation of the upper face. The technique utilized in this series is presented in detail. The consistently excellent results obtained satisfy the aesthetic goals of patients as well as the goals of surgeons, and suggest a renewed interest in the technique based upon its simplicity and easily reproducible results.  相似文献   
69.
70.
The papers which follow are revised and expanded versions of presentations made at the Conference on Improving Florida's Services for the Mentally Ill: The Role of Psychiatry, held in Tallahassee, Florida on October 7–8, 1986, and organized by the Florida Mental Health Institute, University of South Florida. The conference was sponsored by the Florida Department of Health and Rehabilitative Services through the Committee on Public Psychiatry. The authors and their organizational affiliations are listed below  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