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   2099篇
  免费   129篇
  国内免费   1篇
  2021年   22篇
  2020年   11篇
  2019年   11篇
  2018年   21篇
  2017年   16篇
  2016年   23篇
  2015年   66篇
  2014年   65篇
  2013年   95篇
  2012年   94篇
  2011年   115篇
  2010年   68篇
  2009年   59篇
  2008年   95篇
  2007年   95篇
  2006年   94篇
  2005年   86篇
  2004年   94篇
  2003年   92篇
  2002年   87篇
  2001年   95篇
  2000年   81篇
  1999年   65篇
  1998年   22篇
  1997年   25篇
  1996年   24篇
  1995年   16篇
  1994年   13篇
  1993年   17篇
  1992年   59篇
  1991年   41篇
  1990年   33篇
  1989年   40篇
  1988年   31篇
  1987年   39篇
  1986年   34篇
  1985年   46篇
  1984年   29篇
  1983年   22篇
  1982年   13篇
  1981年   13篇
  1980年   10篇
  1979年   22篇
  1978年   9篇
  1976年   10篇
  1975年   12篇
  1974年   12篇
  1972年   13篇
  1971年   11篇
  1967年   9篇
排序方式: 共有2229条查询结果,搜索用时 203 毫秒
31.
Visible fibrinolysis by endothelial cells: Effect of vitamins and sterols   总被引:1,自引:0,他引:1  
We have succeeded in corroborating the enhancing effect of vitamin A, vitamin C, sitosterol and fucosterol on the fibrinolytic activity of endothelial cells. The assay system consisted of anin situ dissolution of a fibrin layer coated onto a culture dish, over which endothelial cells were grown in a culture medium containing 10 % serum. The dissolution was enhanced by the addition of these vitamins and phytosterols to the culture medium.To whom correspondence should be addressed.  相似文献   
32.
33.
The temporal patterns of protein phosphorylation in the adrenal glomerulosa cell were analysed by two-dimensional electrophoresis after stimulation with 10 nM-angiotensin II or various agents [10 nM-12-O-tetradecanoylphorbol 13-acetate (TPA), 50 nM-A23187, 1 microM-nitrendipine], administered singly or in combination. These patterns were compared with the temporal patterns of aldosterone secretion induced by the same agonists and antagonists. After 1 and 30 min of stimulation with angiotensin II, different patterns of protein phosphorylation were observed. A comparison of these patterns reveals that: the phosphorylation of only one protein was persistently enhanced during the continuous incubation with angiotensin II; the phosphorylation of five proteins was transiently enhanced (at 1 min but not 30 min); and the phosphorylation of three proteins did not occur at 1 min but was seen at 30 min. Addition of the phorbol ester TPA alone, which at 30 min is without effect in enhancing aldosterone production, has no effect on protein phosphorylation. The combined addition of TPA and the Ca2+ ionophore, A23187, which, like angiotensin II, evokes a sustained increase in aldosterone production, reproduced the temporal patterns of protein phosphorylation seen after angiotensin II action. Manipulations (A23187 alone, angiotensin II plus nitrendipine) which evoke only a transient rise in aldosterone production rate induce a transient rise in cellular protein phosphorylation. The 1 min patterns of phosphorylation seen after A23187 or combined angiotensin II and nitrendipine (a Ca2+ channel antagonist) are similar to those observed after 1 min of angiotensin II stimulation. These results suggest that, when angiotensin II acts, the initial cellular response is mediated by a different mechanism than that responsible for the sustained response.  相似文献   
34.
Sulfatide-containing liposomes showed the highest degree of adriamycin entrapment of all the liposomes tested. Adriamycin was bound to the sulfatide anions on the liposomal membrane, inserted into the membrane, and incorporated into the aqueous compartment of the vesicle. Liposome-entrapped adriamycin was maintained at a much higher blood level than free adriamycin, and reached a lower concentration in the heart than did the free drug, which might lead to lower cardiotoxicity of the drug. Incorporation of adriamycin into ovarian tumor transplanted into nude mice was increased when entrapped by the sulfatide-containing liposomes. Liposome-entrapped adriamycin did not induce the drastic loss of body weight which occurred with the free drug. The growth of ovarian tumor was inhibited by liposome-entrapped adriamycin to the same degree as free adriamycin. Having these advantages, sulfatide-containing liposomes could be useful carriers of adriamycin for cancer chemotherapy.  相似文献   
35.
S Yamauchi  M Kojima  F Nakayama 《Steroids》1983,41(2):155-164
The preparation and antigenic property of 3 beta-hydroxy-5-cholen-24-oic acid-bovine serum albumin (BSA) conjugate in which the hapten is linked to the carrier protein through an (O-carboxymethyl) oxime bridge at the C-19 position on the steroid nucleus is described. Antibody raised against antigen in the rabbit possessed high titer and specificity to 3 beta-hydroxy-5-cholen-24-oic acid, exhibiting no significant cross-reactions with various bile acids.  相似文献   
36.
Tyrosine hydroxylase purified to apparent homogeneity from the soluble fraction of bovine adrenal medulla had an apparent Mr of about 280,000 by Bio-Gel A-1.5m chromatography, and gave a single band with a Mr of 60,000 by sodium dodesyl sulfate polyacrylamide gel electrophoresis. The enzyme is considered to be composed of four identical subunits. Isoelectric point of purified enzyme was pH 6.0. The amino acid composition of the enzyme was characterized by fairly high contents of glutamic acid and alanine residues. The N-terminal amino acid was determined to be glutamic acid.  相似文献   
37.
38.
Summary Cyclical changes in bovine endometrial gland cells were investigated in six heifers, three at estrus and three at day twelve of the estrous cycle in the luteal phase. The epithelium is generally low at estrus but high in the luteal phase. There are ciliated and non-ciliated cells. The ciliated cells are fewer and lighter and show inconspicuous cyclical changes.The secretory cells show more prominent changes. At estrus, their free border is flat with short microvilli. The conspicuous rough-surfaced endoplasmic reticulum may synthesize protein for later secretion. The Golgi complex seems inactive. The high number of cytosegresomes and dense bodies might express cell regression caused by endocrine changes.In the luteal phase, the cells are lighter with long microvilli. The Golgi apparatus shows vacuoles and immature secretory droplets. Secretory vacuoles with light contents occur in the apical cytoplasm. Some of them appear to discharge their contents into the lumen. This is interpreted as evidence of merocrine secretion. Accumulations of tubular, smooth-surfaced endoplasmic reticulum, masses of glycogen granules, and several fat droplets are present.Some lymphocytes and degranulated granulocytes are seen near the basement membrane, more frequently at estrus.Financial support for this study was received from Anslaget för främjande av medicinsk forskning vid Veterinärhögskolan.The authors express their gratitude to Prof. A. Bane and Dr. J.-E. E. Ringmar, Department of Obstetrics and Gynecology, for their help with the selection and clinical control of the animals and for keeping them in good condition.Post doctoral fellow, No. 43-KO-52 (1968) from the Educational Ministry of Japan.  相似文献   
39.
40.
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