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   4867篇
  免费   0篇
  2012年   189篇
  2011年   349篇
  2010年   145篇
  2009年   1篇
  2008年   303篇
  2007年   419篇
  2006年   450篇
  2005年   431篇
  2004年   451篇
  2003年   485篇
  2002年   475篇
  2001年   299篇
  2000年   514篇
  1999年   261篇
  1998年   35篇
  1997年   12篇
  1991年   8篇
  1990年   9篇
  1989年   9篇
  1988年   8篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1983年   2篇
  1979年   1篇
  1977年   2篇
  1973年   1篇
  1972年   1篇
  1969年   1篇
排序方式: 共有4867条查询结果,搜索用时 93 毫秒
91.
The functional activity of neutrophils, peroxidation products and antioxidative activity of cervical secretion in women with the acute inflammatory process in the upper section of the reproductive tract were under study. The most pronounced changes in the function of neutrophils were observed in women with the low antioxidative activity of cervical slime.  相似文献   
92.
The influence of tumor necrosis factor a (TNF-alpha) and media, conditioned by activated macrophages and lymphocytes and containing a complex of biologically active compounds (including cytokines), on the parameters of lipid metabolism in macrophages was studied. The addition of recombinant TNF-alpha and immunocompetent cell-conditioned media to mouse peritoneal macrophages culture stimulated labelled oleate incorporation into cholesterol esters and triglycerides, as well as labelled glycerine incorporation into cholesterol esters, but inhibited labelled cholesterol incorporation into cholesterol esters. One of the mechanisms of the influence of activated immunocompetent cells on cholesterol metabolism in macrophages was, supposedly, the stimulation of sphigmomyelinase activity by a complex of anti-inflammatory cytokines produced by these cells on their activation.  相似文献   
93.
When studying the cataract pathogenesis in salmon fry, we found changes in the content of individual; phospholipid fractions and fatty acid composition in the liver of diseased and healthy fish. The age-related changes correlated with the increased antioxidant activity and decreased liver content of malondialdehyde.  相似文献   
94.
The capacity of T-lymphocytes to recognize "nonself" and tolerating "self" is formed as a result of positive and negative selection in the thymus. While obtaining and testing specificity of T-hybridomas, we demonstrated that the major part of peripheral pool of CD8+ T-lymphocytes carried receptors specific to "self" MHC class II molecules. Such an unexpected specificity of receptors has been found in some T-cell hybridomas produced by fusion of activated peripheral CD8+ T-lymphocytes with a tumor partner transfected by the coreceptor CD4 gene. The reactivity to "self" is not an experimental artifact due to an increased avidity of interaction of the hybridoma cells with antigen-presenting cells. Also, it is not an expression of reactivity of T-cells to superantigens, products of endogenous viruses of mouse breast cancer. The formation of a pool of such T-cells involves both cells with double receptor specificity and cells coexpressing two alpha-chains of T-cell receptor. Their appearance in the periphery can be due to the capacity of thymocytes differentiating in the direction of CD4+ cells to avoid negative selection via change of expression of coreceptor CD4 to CD8.  相似文献   
95.
Desnitskiĭ AG 《Ontogenez》2004,35(3):165-170
A review of the recent published data on ontogenesis of direct developing and marsupial frogs. The development of these representatives of anuran amphibians seems to be evolutionary advanced and considerably differs from the development of species traditionally used in amphibian embryology.  相似文献   
96.
We studied biochemical features of the lipid and phospholipid composition and patter of fatty acid spectra in lenses of one and two year old salmons bearing cataracts. The lipid complex of lenses of diseased fish underwent significant changes. Cataractogenesis was accompanied by enhanced free radical oxidation and accumulation of malone dialdehyde in lenses of salmons of various age. The intensification of oxidative processes was synchronized with the decreased level of antioxidant protection (reduced glutathione, vitamins A and E). The activity of Ca(2+)-dependent proteolytic enzymes in lenses was determined and its decrease in the case of cataract was shown.  相似文献   
97.
Wine champagnizing, a process involving the use of champagne yeasts immobilized by inclusion into cryogels of polyvinyl alcohol, has been studied. Treatment of yeast cells with the autoregulatory factor d1 was proposed as a means of preventing the cell escape from the carrier matrix. Such a treatment inhibited growth and proliferation processes in yeasts cells, without affecting the activity of fermentation; the resulting champagne had the same organoleptic and chemical characteristics as its counterparts obtained using traditional techniques.  相似文献   
98.
A method of adaptation to cobalt nitrate at high concentrations allowed us to isolate 46 strains of propionic acid bacteria Propionibacterium acidipropionici, resistant to excessive amounts of Co2+ in the medium. Studies of these strains revealed cultures that were most potent in synthesizing vitamin B12. The yield of vitamin B12 was increased 3 times, compared to parent strains.  相似文献   
99.
Results of cytogenetic research of placental villi and amniotic fluid cells culture of the 22-weeks-old fetus with multiple congenital malformations (MCM) are presented. The absence of the short arm in one of the homologue of the chromosome 21 was revealed. Cytogenetic analysis of the fetus father's blood lymphocytes determined the similar chromosome. Further research of the father's karyotype made by FISH-method using specific DNA samples had discovered the absence of subtelomeric parts in the short arm of the chromosome 21 that might be considered as a deletion. It was suggested that the effect of position and interaction of genes could play a key role in appearing of MCM in the fetus in the case when the 21p-chromosome was transferred to it from the healthy parents.  相似文献   
100.
Formation of single- and double strand breaks in DNA which may be discovered by microelectrophoresis in agarose gel is one of the criterion of genetical lesions in cells as a result of apoptosis or of genotoxic agent action. Genotoxic action of nickel chloride at the level of DNA of the individual cells in the initial culture of human embryonic haemopoietic cells was studied. It has been shown that about 2% cells in the studied in vitro populations were in the apoptosis state. Nickel chloride induced increasing of the frequency of formation of electrophoretic tracks of "comet" type with destroyed DNA.  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