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   413篇
  免费   27篇
  国内免费   17篇
  2023年   3篇
  2022年   5篇
  2021年   12篇
  2020年   8篇
  2019年   15篇
  2018年   9篇
  2017年   12篇
  2016年   15篇
  2015年   7篇
  2014年   17篇
  2013年   18篇
  2012年   26篇
  2011年   27篇
  2010年   19篇
  2009年   19篇
  2008年   22篇
  2007年   17篇
  2006年   14篇
  2005年   15篇
  2004年   3篇
  2003年   12篇
  2002年   13篇
  2001年   12篇
  2000年   16篇
  1999年   14篇
  1998年   9篇
  1997年   5篇
  1996年   2篇
  1993年   4篇
  1992年   2篇
  1991年   6篇
  1990年   3篇
  1989年   11篇
  1988年   4篇
  1987年   4篇
  1986年   4篇
  1985年   4篇
  1984年   4篇
  1982年   2篇
  1981年   2篇
  1978年   3篇
  1977年   4篇
  1976年   4篇
  1975年   4篇
  1974年   2篇
  1972年   3篇
  1971年   5篇
  1970年   2篇
  1967年   4篇
  1966年   3篇
排序方式: 共有457条查询结果,搜索用时 15 毫秒
1.
35S-lipoic acid (20 mumol/kg) with different doses of thiamine or 35S-thiamine (50 mumol/kg) with unlabelled lipoic acid where administrated to the white mice stomach. It was established that absorption and entrance of both lipoic acid and thiamine when they were in 1:5 quantities in organs and tissues were maximal. The activity of Na+, K-ATPase determined in stomach, duodenum and small intestine was the maximal too.  相似文献   
2.
Rabbits were immunized by homogenates of endometrium obtained from women during 10-12 weeks of gestation. A specific antiserum was obtained by absorption of the crude antiserum by blood cells and plasma proteins of men with different kinds of ABO and Rh antigens, till disappearance of positive reaction with men's serum protein in the Ouchterlony test. Such an adsorbed specific antiserum continued to react with the sera of pregnant women. Two antigens, numbers 1 and 2, respectively, were determined by the Ouchterlony test. Another group of rabbits was immunized by antigens detected in the precipitation test. A monospecific antidecidual antiserum (ADS 1092) was obtained against number 2 antigens. This antiserum revealed only one antigen in sera of women with gestation and did not react with sera of non-pregnant women. In the slides of endometrium of pregnant women of 10-12 weeks of gestation ADS 1092 had a strong positive reactive with the cytoplasm of one type of endometrium cells. The immunomorphological analysis by the non-direct Coons test and the PAP-test permits to identify cells with the positive reaction as granular cells. It is concluded that the granular cells may be a source of one of the serum antigens detected in women with gestation.  相似文献   
3.
4.
5.
6.
A puzzling population-genetic phenomenon widely reported in allozyme surveys of marine bivalves is the occurrence of heterozygote deficits relative to Hardy-Weinberg expectations. Possible explanations for this pattern are categorized with respect to whether the effects should be confined to protein-level assays or are genomically pervasive and expected to be registered in both protein- and DNA-level assays. Anonymous nuclear DNA markers from the American oyster were employed to reexamine the phenomenon. In assays based on the polymerase chain reaction (PCR), two DNA-level processes were encountered that can lead to artifactual genotypic scorings: (a) differential amplification of alleles at a target locus and (b) amplification from multiple paralogous loci. We describe symptoms of these complications and prescribe methods that should generally help to ameliorate them. When artifactual scorings at two anonymous DNA loci in the American oyster were corrected, Hardy-Weinberg deviations registered in preliminary population assays decreased to nonsignificant values. Implications of these findings for the heterozygote-deficit phenomenon in marine bivalves, and for the general development and use of PCR-based assays, are discussed.   相似文献   
7.
The distribution of Na+ pump sites (Na+-K+-ATPase) in the secretory epithelium of the avian salt gland was demonstrated by freeze-dry autoradiographic analysis of [(3)H] ouabain binding sites. Kinetic studies indicated that near saturation of tissue binding sites occurred when slices of salt glands from salt-stressed ducks were exposed to 2.2 μM ouabain (containing 5 μCi/ml [(3)H]ouabain) for 90 min. Washing with label-free Ringer's solution for 90 min extracted only 10% of the inhibitor, an amount which corresponded to ouabain present in the tissue spaces labeled by [(14)C]insulin. Increasing the KCl concentration of the incubation medium reduced the rate of ouabain binding but not the maximal amount bound. In contrast to the low level of ouabain binding to salt glands of ducks maintained on a freshwater regimen, exposure to a salt water diet led to a more than threefold increase in binding within 9-11 days. This increase paralleled the similar increment in Na+-K+-ATPase activity described previously. [(3)H]ouabain binding sites were localized autoradiographically to the folded basolateral plasma membrane of the principal secretory cells. The luminal surfaces of these cells were unlabeled. Mitotically active peripheral cells were also unlabeled. The cell-specific pattern of [(3)H]ouabain binding to principal secretory cells and the membrane-specific localization of binding sites to the nonluminal surfaces of these cells were identical to the distribution of Na+-K+-ATPase as reflected by the cytochemical localization of ouabain-sensitive and K+-dependent nitrophenyl phosphatase activity. The relationship between the nonluminal localization of Na+-K+-ATPase and the possible role of the enzyme n NaCl secretion is considered in the light of physiological data on electrolyte transport in salt glands and other secretory epithelia.  相似文献   
8.
Distribution of 3H-carminomycin with the specific activity of 390 mCu/g prepared by the method of isotope exchange in 3H2O was investigated on mice treated with the antibiotic administered intravenously in a dose of 2 mg/kg. It was shown that the antibiotic rapidly accumulated in the mouse tissues, mainly in the liver, kidneys, lungs and spleen. The carminomycin blood levels markedly decreased within the first 5 minutes after the drug administration and remained rather stable during the following 6 hours. The concentrations of carminomycin in the heart muscle were comparatively low. Still, at early periods they were much higher than those in the skeletal muscles. The difference disappeared by 24 hours. Carminomycin penetrated into the tissues of the brain.  相似文献   
9.
10.
For studying anatomy of the alive human heart, a new method of ultrasonic echography has been used. With its assistance it is possible to see all the cardiac chambers, interventricular and interatrial septa, tricuspidal and mitral valves, their chordae, papillary muscles, myocardium and pericardium. Not only their statics, but also their dynamics are investigated, when the heart contracts and its valves make movements. Owing to this, possibilities for studying cardiac anatomy in the alive people.  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