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   1501篇
  免费   154篇
  国内免费   60篇
耳鼻咽喉   3篇
儿科学   69篇
妇产科学   21篇
基础医学   171篇
口腔科学   26篇
临床医学   187篇
内科学   364篇
皮肤病学   54篇
神经病学   56篇
特种医学   300篇
外科学   97篇
综合类   31篇
预防医学   51篇
眼科学   19篇
药学   109篇
中国医学   3篇
肿瘤学   154篇
  2023年   6篇
  2022年   9篇
  2021年   17篇
  2020年   21篇
  2019年   25篇
  2018年   41篇
  2017年   25篇
  2016年   30篇
  2015年   37篇
  2014年   25篇
  2013年   56篇
  2012年   42篇
  2011年   44篇
  2010年   53篇
  2009年   68篇
  2008年   39篇
  2007年   76篇
  2006年   35篇
  2005年   40篇
  2004年   23篇
  2003年   25篇
  2002年   28篇
  2001年   20篇
  2000年   27篇
  1999年   30篇
  1998年   75篇
  1997年   83篇
  1996年   105篇
  1995年   65篇
  1994年   64篇
  1993年   54篇
  1992年   19篇
  1991年   20篇
  1990年   25篇
  1989年   46篇
  1988年   37篇
  1987年   40篇
  1986年   47篇
  1985年   43篇
  1984年   12篇
  1983年   15篇
  1982年   14篇
  1981年   14篇
  1980年   14篇
  1979年   14篇
  1978年   14篇
  1977年   11篇
  1976年   14篇
  1975年   14篇
  1973年   5篇
排序方式: 共有1715条查询结果,搜索用时 15 毫秒
1.
2.
Alpha-Melanocyte-stimulating hormone (MSH) is a potent anti-inflammatory agent in many models of inflammation, suggesting that it inhibits a critical step common to different forms of inflammation. We showed previously that alpha-MSH inhibits nitric oxide (NO) production in cultured macro-phages. To determine how alpha-MSH acts in vivo, we induced acute hepatic inflammation by administering endotoxin (LPS) to mice pretreated with Corynebacterium parvum, alpha-MSH prevented liver inflammation even when given 30 min after LPS administration. To determine the mechanisms of action of alpha-MSH, we tested its influence on NO, infiltrating inflammatory cells, cytokines, and chemokines. Alpha-MSH inhibited systemic NO production, hepatic neutrophil infiltration, and increased hepatic mRNA abundance for TNF alpha, and the neutrophil and monocyte chemokines (KC/IL-8 and MCP-1). We conclude that alpha-MSH prevents LPS-induced hepatic inflammation by inhibiting production of chemoattractant chemokines which then modulate infiltration of inflammatory cells. Thus, alpha-MSH has an effect very early in the inflammatory cascade.  相似文献   
3.
4.
5.
BACKGROUND: Since 1997, a number of trials have shown promising results in treating generalized vitiligo with narrowband ultraviolet B (UVB) both in adults and children. However, there is little knowledge concerning the duration and permanency of the treatment-induced repigmentation. OBJECTIVE: Our main objective was to perform a follow-up trial of successfully treated patients receiving narrowband UVB for generalized vitiligo. METHODS: We have investigated to what degree the treatment-induced repigmentation remains stable for up to 2 years post-treatment. We performed an initial open trial including 31 patients with generalized vitiligo. They received narrowband UVB thrice weekly for up to 12 months. Patients experiencing > 75% repigmentation were defined responders and were included in the follow-up trial. Responders were followed every 6 months for up to 2 years after cessation of treatment. We observed the pigmentation status and registered any changes indicating loss of pigmentation and relapse. RESULTS: Eleven of the 31 treated patients were included in the follow-up trial. Six patients had relapse and five patients had stable response 24 months after cessation of treatment. Four out of six relapses were within 6 months post-treatment. CONCLUSION: In our study population of 31 patients with generalized vitiligo, five patients (16%) experienced > 75% stable repigmentation 2 years after cessation of a treatment programme of up to 1 years narrowband UVB therapy.  相似文献   
6.
We report two clinical pregnancies occurring after intracytoplasmic sperm injection (ICSI) using cryopreserved spermatozoa obtained from testicular biopsy, made in two different infertility situations in our clinic. The first patient showed a secretory azoospermia associated with elevated serum follicular stimulating hormone (FSH) level and spermiogenesis maturation arrest. The second patient was affected by azoospermia resulting from bilateral epididymal obstruction. Spermatozoa present in the wet preparation of testicular biopsy made on the day of scrotal exploration were cryopreserved within the testicular tissue for both men. Intracytoplasmic injections were performed at a later date, using spermatozoa prepared from frozen-thawed tissues. In each case, three embryos were obtained and transferred in utero. The transfers resulted in a twin pregnancy for the first case, and in a singleton pregnancy for the second. Living foetuses were seen in the ultrasound scan at the 7th week and both pregnancies are proceeding to date beyond 30 weeks without complications.   相似文献   
7.
8.
9.
Thirty-five patients hospitalized for recent angiographically documented arterial occlusion in the legs (27 femoropopliteal arteries and eight grafts) benefited from local fibrinolytic therapy delivered at the site of the occlusion with a 4- or 5-F catheter. This therapy combined a continuous urokinase (UK) infusion of 1,000 U/kg/hour and a lysyl plasminogen (LYS-PLG) infusion of 15 microkatals every 30 minutes. Angiographically confirmed lysis was obtained in 85% of the cases. Only 3% of the patients had major and 6% had minor groin hematomas. Only two patients had concentrations of fibrinogen as low as 100 mg/dl. Intravascular infusion of UK-LYS-PLG is as effective as streptokinase. Its excellent tolerance makes it a good alternative in the treatment of acute ischemia in the lower limbs.  相似文献   
10.
Birnholz  JC 《Radiology》1986,158(3):805-807
Ultrasound (US) can be used to visualize vertebral segments, suggesting a quantitative means of studying vertebral column growth in utero and thus a means of detecting developmental abnormalities. US images of the lumbar spine were obtained in 128 clinically normal fetuses between the gestational age of 11 through 41 weeks. A large-aperture, dynamically focused US system capable of regional magnification was used. Average lumbar spacing was calculated from distance between centrums of at least four lumbar bodies. The average distance between lumbar centrums increased nearly linearly throughout the second and third trimesters (r2 = 0.98). Enhanced anatomic display implies new capabilities for recognizing developmental abnormalities antenatally.  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