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   18925篇
  免费   1427篇
  国内免费   81篇
耳鼻咽喉   139篇
儿科学   459篇
妇产科学   357篇
基础医学   2573篇
口腔科学   584篇
临床医学   2140篇
内科学   4499篇
皮肤病学   243篇
神经病学   1780篇
特种医学   643篇
外科学   2448篇
综合类   313篇
一般理论   47篇
预防医学   1617篇
眼科学   553篇
药学   1049篇
中国医学   14篇
肿瘤学   975篇
  2021年   280篇
  2020年   179篇
  2019年   256篇
  2018年   274篇
  2017年   214篇
  2016年   271篇
  2015年   334篇
  2014年   445篇
  2013年   844篇
  2012年   1008篇
  2011年   1068篇
  2010年   635篇
  2009年   584篇
  2008年   944篇
  2007年   1026篇
  2006年   1052篇
  2005年   1078篇
  2004年   1056篇
  2003年   967篇
  2002年   1034篇
  2001年   192篇
  2000年   129篇
  1999年   200篇
  1998年   227篇
  1997年   218篇
  1996年   205篇
  1995年   174篇
  1994年   154篇
  1993年   173篇
  1992年   142篇
  1991年   127篇
  1990年   127篇
  1989年   135篇
  1988年   114篇
  1987年   122篇
  1986年   117篇
  1985年   144篇
  1984年   179篇
  1983年   156篇
  1982年   208篇
  1981年   200篇
  1980年   195篇
  1979年   122篇
  1978年   133篇
  1977年   132篇
  1976年   140篇
  1975年   129篇
  1974年   113篇
  1973年   95篇
  1972年   87篇
排序方式: 共有10000条查询结果,搜索用时 500 毫秒
21.
22.
We compared three maintenance immunosuppressive regimens in a rapid discontinuation of prednisone protocol. From March 1, 2001, through December 31, 2003, 239 first and second kidney transplant recipients (166 LD; 73 DD) were randomized. All recipients were treated with Thymoglobulin; all received steroids intraoperatively and for 5 days postoperatively. Randomization was to cyclosporine-mycophenolate mofetil (n = 85); high-level tacrolimus (TAC) (8-12 ng/mL)-low-level sirolimus (SRL) (3-7 ng/mL) (n = 72); or low-level TAC (3-7 ng/mL)-high-level SRL (8-12 ng/mL) (n = 82). We found no difference at 24 months between groups in patient, graft, death-censored graft, or acute rejection-free graft survival, or in kidney function. Wound complications were more common in SRL-treated recipients (p = 0.02); we found no other differences between groups in complication rates. Our data suggest that excellent patient and graft survival and low rejection rates can be obtained using a variety of maintenance protocols without prednisone.  相似文献   
23.
24.
25.
26.
Arthur I Gilbert 《Hernia》2005,9(4):400-400
  相似文献   
27.
Background: The authors compared the efficacy of the different approaches to saphenous nerve block.

Methods: The following approaches to saphenous nerve block were compared in 10 volunteers: perifemoral, transsartorial, block at the medial femoral condyle, below-the-knee field block, and blockade at the level of the medial malleolus. Each volunteer underwent all five blocks, and the interval between blocks was 3-7 days. The sequence of injection was randomized by Latin square design. Sensory blockade at the medial aspects of the leg and foot and the strength of the anterior thigh muscles were noted.

Results: The transsartorial, perifemoral, and below-the-knee field block approaches were more effective than block at the medial femoral condyle in providing sensory anesthesia to the medial aspect of the leg. The transsartorial approach was more effective than block at the medial femoral condyle and below-the-knee field block in providing sensory anesthesia to the medial aspect of the foot. Compared with the perifemoral approach, the transsartorial approach did not cause weakness of the hip flexors and the knee extensors. In volunteers with partial numbness in the medial aspect of the foot, supplemental block of the medial dorsal cutaneous branch of the superficial peroneal nerve resulted in complete sensory blockade.  相似文献   

28.
29.
We report on 7 patients (6 M, 1 F) with Coffin-Lowry syndrome who have a sensorineural hearing deficit in addition to developmental delay and characteristic facial changes. One of the patients also had a history of premature exfoliation of primary teeth. These are previously unappreciated clinical signs that may aid in the early diagnosis of Coffin-Lowry syndrome. Early diagnosis and recognition of a hearing deficit in the patient can lead to the use of hearing aids to help the patient achieve his or her full potential. These “;new”; clinical manifestations expand the phenotype of Coffin-Lowry syndrome and constitute an additional indication of pleiotropy. © 1993 Wiley-Liss, Inc.  相似文献   
30.
3β-hydroxysteroid dehydrogenase/Δ5−Δ4isomerase (3β-HSD) activity was measured in primary dissociated cell cultures prepared from telencephalons of developing zebra finches. 3β-HSD activity was confirmed after cultures were incubated with [7-3H]pregneno- lone (Preg) or (1,2,6,7-3H-) dehydroepiandrosterone (DHEA) and3H-progesterone (Prog) and3H-androstenedione (AE) were detected in the medium. Product identity was confirmed by recrystallizations and by HPLC analysis. When DHEA was used as substrate,3H-estradiol and3H-estrone were also detected in the culture medium, presumably derived from the aromatization of3H-AE or3H-T produced from3H-DHEA. To test this idea, cultures were incubated with3H-DHEA together with radioinert AE or with fadrozole HCl, a potent and specific aromatase inhibitor. In the presence of radioinert AE,3H-AE increased but metabolites of3H-AE decreased in the media; in the presence of fadrozole,3H-estrogens decreased but3H-AE and its androgenic metabolite3H-5β-androstanedione increased. These data demonstrate 3β-HSD activity in the songbird brain. The presence of Prog and estradiol in these cultures suggest that Preg and DHEA can potentially serve as substrates for the ultimate formation of active sex steroids in the songbird telencephalon.  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