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   243647篇
  免费   20612篇
  国内免费   14464篇
耳鼻咽喉   2192篇
儿科学   3048篇
妇产科学   4893篇
基础医学   28445篇
口腔科学   4218篇
临床医学   31141篇
内科学   39953篇
皮肤病学   2845篇
神经病学   13578篇
特种医学   8606篇
外国民族医学   99篇
外科学   26748篇
综合类   34477篇
现状与发展   49篇
一般理论   45篇
预防医学   15201篇
眼科学   6687篇
药学   24416篇
  175篇
中国医学   11105篇
肿瘤学   20802篇
  2024年   725篇
  2023年   3522篇
  2022年   8774篇
  2021年   11531篇
  2020年   8458篇
  2019年   7657篇
  2018年   8044篇
  2017年   7034篇
  2016年   6717篇
  2015年   10165篇
  2014年   12805篇
  2013年   11973篇
  2012年   17622篇
  2011年   19324篇
  2010年   11802篇
  2009年   9448篇
  2008年   12831篇
  2007年   12886篇
  2006年   12440篇
  2005年   12525篇
  2004年   8652篇
  2003年   7685篇
  2002年   6654篇
  2001年   6028篇
  2000年   6135篇
  1999年   6447篇
  1998年   3665篇
  1997年   3683篇
  1996年   2800篇
  1995年   2591篇
  1994年   2245篇
  1993年   1500篇
  1992年   2294篇
  1991年   2000篇
  1990年   1669篇
  1989年   1458篇
  1988年   1267篇
  1987年   1176篇
  1986年   941篇
  1985年   748篇
  1984年   491篇
  1983年   381篇
  1982年   225篇
  1981年   202篇
  1980年   191篇
  1979年   243篇
  1978年   141篇
  1977年   112篇
  1976年   97篇
  1974年   116篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Objective: To observe the effect of Ureaplasma urealyticum (UU) infection on the IL-1α and IL-6 secretion by rat Sertoli cells. Methods: Eight 20-day-old UU-free male SD rats (average weight 40 g) were used. Under sterile condition, the testes were removed and separately digested with collagenase typeⅡand hyaluronidase. High purity Sertoli cells were then isolated and adjusted to a concentration of 8×105/mL with DMEM/Ham's F-12. In the infected group, 1 mL Sertoli cell suspension and 100 mL UU (serotype 8, T960) were introduced into one well of a 24 well culture plate. In the control group, 1 mL Sertoli cell suspension and 100 mL medium were introduced. IL-1αand IL-6 were determined in the culture supernatant with ELISA. Results: The production of IL-1αwas significantly lower and of IL-6 significantly higher in the infected than those in the control groups (P<0.01). Conclusion: UU infection reduces the IL-1αand increases the IL-6 secretion by rat Sertoli cells. UU infection is probably involved in  相似文献   
132.
Conventional computerized tomography (CT) technique is based on the absorption contrast. In recent years, X-ray phase-contrast CT (PCCT) has been developing rapidly. It uses the phase information to reconstruct the object and provide high contrast and spatial resolution. Diffraction enhanced imaging (DEI) method is one of the three phase-sensitive X-ray imaging techniques. DEI method employs an analyzer crystal to extract the object's refraction information which can be used for CT. However, when DEI refraction CT is combined with the conventional CT algorithm, it should be satisfied that the refraction information of an arbitrary point in the object is invariable at every projection view. In this paper, the invariance condition of refraction information is analyzed and two feasible methods are provided for reconstruction. Using these two methods, two samples of weak absorption are reconstructed with the experimental data obtained at Beijing Synchrotron Radiation Facility (BSRF).  相似文献   
133.
134.
Direct effect of VX and soman on nicotinic receptors   总被引:1,自引:0,他引:1  
  相似文献   
135.
136.
Health status and medical care utilization   总被引:3,自引:0,他引:3  
  相似文献   
137.
It is often necessary to perform genioplasty in the same time of the surgical orthodontics. From Feb. 1985 to Feb. 1987, 31 cases of genioplaties were accomplished by using of cortical plate of mental mandibular bone. The ages of patients were ranged from 17-37 years old. The results of operations were satisfied.  相似文献   
138.
139.
The xanthine oxidase catalysed release of superoxide free radicals (O2-) from endogenous hypoxanthine was determined in homogenates of synovium obtained from three groups of patients, those undergoing primary or revision total hip replacement (THR) for osteoarthritis and those undergoing arthroscopy of the knee for semilunar disc injuries. The concentrations of hypoxanthine in homogenates obtained during THR were found to be significantly higher than those in the group with semilunar disc injuries. The results suggest that there is a greater predisposition to free radical release and tissue damage in osteoarthritis.  相似文献   
140.
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