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   1379篇
  免费   72篇
  国内免费   6篇
儿科学   24篇
妇产科学   20篇
基础医学   175篇
口腔科学   7篇
临床医学   72篇
内科学   224篇
皮肤病学   46篇
神经病学   229篇
特种医学   44篇
外科学   119篇
综合类   5篇
预防医学   35篇
眼科学   25篇
药学   49篇
中国医学   3篇
肿瘤学   380篇
  2023年   9篇
  2022年   11篇
  2021年   25篇
  2020年   11篇
  2019年   18篇
  2018年   27篇
  2017年   16篇
  2016年   22篇
  2015年   22篇
  2014年   37篇
  2013年   45篇
  2012年   102篇
  2011年   74篇
  2010年   39篇
  2009年   41篇
  2008年   60篇
  2007年   74篇
  2006年   76篇
  2005年   84篇
  2004年   69篇
  2003年   86篇
  2002年   77篇
  2001年   16篇
  2000年   23篇
  1999年   23篇
  1998年   16篇
  1997年   18篇
  1996年   11篇
  1995年   6篇
  1994年   8篇
  1993年   11篇
  1992年   37篇
  1991年   30篇
  1990年   34篇
  1989年   20篇
  1988年   23篇
  1987年   24篇
  1986年   15篇
  1985年   15篇
  1984年   11篇
  1983年   5篇
  1982年   5篇
  1981年   5篇
  1980年   9篇
  1979年   9篇
  1977年   8篇
  1975年   7篇
  1969年   6篇
  1968年   4篇
  1967年   4篇
排序方式: 共有1457条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
In the 2002-2003 season, influenza B virus Victoria strains were epidemic after a 6-year absence in Kobe City, Japan. They reacted poorly to the immune ferret sera prepared for use against the previous strain. An amino acid substitution in the HA1 region caused them to acquire an N-linked glycosylation site.  相似文献   
995.
It is known that taste can act as a conditioned stimulus (CS) for conditioned food aversion. In the present study, in order to examine whether or not the temperature of drinking water can be a CS, we conducted behavioral experiments in Wistar rats. The following results were obtained: (1) The rats subjected to aversive conditioning to 5 or 40 degrees C distilled water could learn to avoid these CSs, but they did not avoid any taste stimuli. (2) The rats subjected to aversive conditioning to 5 or 40 degrees C 0.1 M sucrose developed a generalized avoidance to sucrose at any temperature. (3) When rats familiarized to 25 degrees C 5 mM saccharin-Na (Sacc) were subjected to aversive conditioning to 5 or 40 degrees C Sacc, they avoided the respective CS, but they did not generalize it to any other stimuli even if having the same temperature as the CS. (4) The rats which had undergone transection of the taste nerves (chorda tympani and glossopharyngeal nerves) could acquire the conditioned response to the temperature of the CS. These results suggest that rats can be conditioned to temperature aversion and that the taste nerves are not needed in the formation of this conditioning.  相似文献   
996.
A panel of human anti-anthrax protective antigen IgG1 monoclonal antibodies were evaluated to determine the mechanism of toxin neutralization. AVP-22G12, AVP-1C6 and AVP-21D9 bound to the protective antigen with picomolar affinities to distinct non-overlapping linear epitopes. Two of the antibodies neutralized the anthrax toxin by completely inhibiting the protective antigen oligomer assembly process in vitro.  相似文献   
997.
Liver-type fatty-acid-binding protein (L-FABP), which has high affinity for long-chain fatty acid oxidation products, may be an effective endogenous antioxidant. To examine the role of L-FABP in tubulointerstitial damage, we used a unilateral ureteral obstruction (UUO) model. We established human L-FABP (hL-FABP) gene transgenic (Tg) mice and compared the tubulointerstitial pathology of the Tg mice (n = 23) with that of the wild-type (WT) mice (n = 23). Mice were sacrificed on days 2, 4, 5, or 7 after UUO. Although mouse L-FABP was not expressed in WT mice, hL-FABP was expressed in the proximal tubules of the Tg mice with UUO (UUO-Tg) and in sham-operated Tg mice. The expression of renal hL-FABP was significantly increased in UUO-Tg compared with sham-operated Tg mice. The number of macrophages (F4/80) infiltrating the interstitium and the level of expression of MCP-1 and MCP-3 were significantly lower in UUO-Tg kidneys compared with UUO-WT kidneys. In UUO-Tg kidneys, the degree of the tubulointerstitial injury and the deposition of type I collagen were significantly lower than that of UUO-WT kidneys. On day 7, lipid peroxidation product accumulated in the UUO-WT kidneys but not in that of UUO-Tg kidneys. In conclusion, renal L-FABP may reduce the oxidative stress in the UUO model, ameliorating tubulointerstitial damage.  相似文献   
998.
In order to confirm 14-3-3 sigma (sigma) protein distribution in human tissues, immunohistochemistry was performed using various paraffin-embedded human tissues. In normal human tissues, the strongest immunoreactivity for 14-3-3sigma protein was observed in squamous epithelia at various sites, followed by basal cells of the trachea, bronchus and basal or myoepithelial cells of various glands. Moderate to weak 14-3-3sigma immunoreactivity was seen in the epithelial cells of the alimentary tract, gall bladder, urinary tract and endometrium. In the lung, 14-3-3sigma immunoreactivity was also observed in hyperplastic type II alveolar cells and metaplastic squamous cells. Immunohistochemical study using non-small-cell lung cancers revealed that 14-3-3sigma immunoreactivity was stronger in squamous cell carcinomas than in adenocarcinomas. The present study revealed that 14-3-3sigma expression was exclusively present in various epithelial cells and had a tendency to be stronger in cells destined for squamous epithelium or differentiating toward squamous cells in human normal and neoplastic cells.  相似文献   
999.
Shimano  Reika  Inubushi  Ritsuko  Oshima  Yoko  Adachi  Akio 《Virus genes》1999,18(3):197-201
There are several major strategies against HIV/AIDS. Of these, the gene therapy is a novel, challenging, and promising one. The target genes, which have been extensively studied for the potential gene therapy of HIV/AIDS, include those of cellular and viral origins. Especially, trans-dominant negative Tat, Rev, Env, Pol, and Gag mutants of HIV have currently attracted considerable attention. In this brief review, we summarize the nature of the HIV/SIV mutants of this category and discuss their future use for gene therapy with special reference to the dominant negative Gag mutants of HIV-1.  相似文献   
1000.
We investigated the cell kinetics of the endometrium in hysterectomy specimens taken for leiomyoma from 22 women with regular ovulatory menstrual cycles. Formalin-fixed, paraffin-embedded tissue sections were examined for proliferating activity using histone H3 messenger RNA in situ hybridization (H3 mRNA-ISH) and immunostaining for the Ki-67 antigen. The relationship of the proliferative activity of endometrial cells to the immunohistochemical expression of the estrogen receptor (ER) and the progesterone receptor (PR) was also examined. During the menstrual cycle, H3 mRNA expression was observed in both the epithelial cells and the stromal cells of the endometrium. In the functional layer, the labeling indices for H3 mRNA (H3 mRNA-LIs) in the epithelial cells peaked in the late proliferative phase, decreased sharply in the early secretory phase, and remained unchanged thereafter. On the other hand, H3 mRNA-LIs of stromal cells displayed two peaks: one in the midproliferative phase and the other in the late secretory phase, the former peak being the greater. In the basal layer, epithelial cells and stromal cells showed low H3 mRNA-LIs and no significant variation throughout the menstrual cycle. The H3 mRNA-LIs correlated well with the Ki-67-LIs and were lower than the corresponding Ki-67-LIs. The regression coefficient (H3 mRNA-LIs against the Ki-67-LIs) was 0.33 for epithelial cells and 0.49 for stromal cells, suggesting that the cell cycle time was longer for epithelial cells than for stromal cells. The proliferative activity of endometrial cells showed close relationships with the expressions of ER and PR in the endometrium. When used in combination with other proliferative markers in paraffin-embedded tissue sections, H3 mRNA-ISH could open broader perspectives on the cell kinetics of the endometrium.  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