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   2089篇
  免费   84篇
  国内免费   9篇
耳鼻咽喉   5篇
儿科学   106篇
妇产科学   71篇
基础医学   299篇
口腔科学   41篇
临床医学   186篇
内科学   463篇
皮肤病学   30篇
神经病学   132篇
特种医学   51篇
外科学   142篇
综合类   71篇
一般理论   3篇
预防医学   162篇
眼科学   40篇
药学   226篇
  1篇
中国医学   26篇
肿瘤学   127篇
  2023年   8篇
  2022年   20篇
  2021年   53篇
  2020年   34篇
  2019年   51篇
  2018年   69篇
  2017年   30篇
  2016年   58篇
  2015年   49篇
  2014年   63篇
  2013年   91篇
  2012年   151篇
  2011年   145篇
  2010年   89篇
  2009年   53篇
  2008年   129篇
  2007年   122篇
  2006年   104篇
  2005年   107篇
  2004年   92篇
  2003年   92篇
  2002年   68篇
  2001年   45篇
  2000年   54篇
  1999年   35篇
  1998年   11篇
  1997年   12篇
  1996年   8篇
  1995年   8篇
  1994年   9篇
  1993年   10篇
  1992年   24篇
  1991年   18篇
  1990年   20篇
  1989年   18篇
  1988年   9篇
  1987年   18篇
  1986年   18篇
  1985年   16篇
  1984年   15篇
  1983年   9篇
  1979年   8篇
  1977年   10篇
  1976年   11篇
  1974年   10篇
  1973年   13篇
  1972年   10篇
  1971年   8篇
  1970年   12篇
  1969年   13篇
排序方式: 共有2182条查询结果,搜索用时 15 毫秒
1.
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Heavy metal concentrations in surface soils of Reserved Forests (RFs) have a significant impact on...  相似文献   
2.
3.
4.
Zero-order release of oxprenolol hydrochloride was obtained by controlling the swelling and erosion of the matrix. This formulation involves only mixing of drug, hydroxypropylmethylcellulose (HPMC), and sodium carboxymethylcellulose (Na CMC) at the ratio of 1:0.4:1.6, respectively, and compressing the mixture directly into tablets. The in vitro release pattern from this optimized matrix tablet was reproducible. Accelerated stability studies revealed that the optimized formulation remains stable for an approximately 2-year shelf life. This sustained-release (SR) tablet was evaluated in dogs, and for comparison a conventional (CV) formulation was also given at the same dose level. Plasma oxprenolol levels were monitored by a sensitive and specific high-performance liquid chromatographic (HPLC) method. Significant differences in the pharmacokinetic parameters, i.e., lower C max, higher values of t max, MRT, AUC, and plasma concentration at 24 hr, and nearly constant plasma levels over 12 hr, indicated that the SR matrix tablet is superior to the CV rapid-releasing formulation. The in vitro release parameters and in vivo pharmacokinetics correlated well.  相似文献   
5.
Intravascular papillary endothelial hyperplasia (IPEH) is an unusual vascular lesion of proliferating endothelial cells. It is more frequently seen in the extremities, particularly in the fingers. Oral IPEH has been reported with the common sites being lip, tongue, and buccal mucosa. In this article, we present a case of oral IPEH of the floor of the mouth, an unusual location, presenting in a 9-month-old male. The histogenesis, histologic features, and ultrastructural features are also reviewed. A misdiagnosis of angiosarcoma can be made in a case of IPEH due to similar histopathologic features. It is imperative to rule out this error by an elaborate histopathologic evaluation ofthese lesions.  相似文献   
6.
The alterations in the oesophageal epithelium were studied in mice after a single whole-body exposure to 7.5 Gy of Co-60 gamma rays in presence or absence of 2-mercaptopropionyl glycine. The epithelium showed an increase in the thickness which reached a maximum on the third day and then decreased gradually up to seventh day after irradiation in the non-drug treated group. In the 2-mercaptopropionyl glycine treated animals the epithelial thickness remained in the normal range except on the day 7 when it was significantly lower than normal. The total cell population registered a steady decline from one to seven days post-irradiation in both groups, but the number of cells was more in the 2-mercaptopropionyl glycine treated group. The number of pycnotic nuclei showed an inverse relationship to the total cell population, it increased continuously up to seven days in both the protected and non-protected groups. However, pycnotic nuclei were significantly lower in the protected group on days 3, 5 and 7 in non-protected group.  相似文献   
7.
In the brain, nitric oxide (NO) has been identified as a messenger molecule and a mediator of excitatory amino acid-induced neurotoxicity. In this study, the effects of NO on serum-induced mitogenesis and cell proliferation of the cerebellar glial cells were assessed. NO-generating agent, S-nitroso-N-acetylpenicillamine (SNAP) increased intracellular cyclic guanosine monophosphate (cGMP) levels. Furthermore, 2 chemically dissimilar NO-generating agents, SNAP and sodium nitroprusside (SNP) inhibited serum-induced thymidine incorporation and cell proliferation. The antimitogenic effect of NO was mimicked by 8-bromo-cGMP and blocked by hemoglobin, a known inhibitor of NO. The effect of NO was not cytotoxic, since the cells were not stained with Trypan blue and did not show increased release of lactate dehydrogenase in the culture supernatants. However, NO-treated cells showed decreased conversion of tetrazolium to blue formazan suggesting that NO inhibited mitochondrial activity in the glial cells. These results demonstrate that NO inhibits serum-induced mitogenesis and cell proliferation of cultured rat cerebellar glial cells.  相似文献   
8.
Two children out of three siblings of a family presented with tiredness, fatigue, and breathlessness for more than 6 months. Examination of peripheral blood smear, bone marrow aspirate, and a positive acidified serum test (HEMPAS) revealed these children to be a case of congenital dyserythropoietic anemia type II. This case is reported because of its rarity.  相似文献   
9.
An autopsy finding of sudden death due to disseminated intra-vascular sickling of RBCs in a young adult male from Madhya Pradesh while undergoing army recruitment rally, is reported because of its rarity in this part of the country.  相似文献   
10.
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