全文获取类型
收费全文 | 536篇 |
免费 | 139篇 |
出版年
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 17篇 |
2015年 | 19篇 |
2014年 | 17篇 |
2013年 | 28篇 |
2012年 | 31篇 |
2011年 | 33篇 |
2010年 | 20篇 |
2009年 | 18篇 |
2008年 | 20篇 |
2007年 | 26篇 |
2006年 | 34篇 |
2005年 | 25篇 |
2004年 | 25篇 |
2003年 | 21篇 |
2002年 | 17篇 |
2001年 | 19篇 |
2000年 | 16篇 |
1999年 | 18篇 |
1998年 | 18篇 |
1997年 | 12篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 9篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 15篇 |
1989年 | 12篇 |
1988年 | 12篇 |
1987年 | 12篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1981年 | 5篇 |
1980年 | 9篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 5篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1968年 | 5篇 |
1967年 | 5篇 |
排序方式: 共有675条查询结果,搜索用时 46 毫秒
1.
Elliott C. Kulakowski Joseph Maturo Stephen W. Schaffer 《Archives of biochemistry and biophysics》1981,210(1):204-209
Cardiac sarcolemma preparations of both pig and rat ventricles were found to possess two sets of taurine-binding components. The two proteins from pig heart were solubilized with the detergent Ammonyx-Lo. Characterization of these solubilized proteins revealed that both components are glycoproteins and retain the binding properties observed for the membrane isolate. However, the characterization also revealed several differences between the proteins including their binding specificities, their affinities for taurine, their binding isotherms, and their molecular sizes. Possible functions of these two taurine-binding proteins are discussed. 相似文献
2.
Yohimbine increases plasma insulin concentrations of dogs 总被引:1,自引:0,他引:1
W H Hsu D D Schaffer M H Pineda 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1987,184(3):345-349
Recent evidence suggests that catecholamines inhibit insulin release by stimulating alpha 2-adrenoreceptors in beta-cells of the pancreatic islets. In the present study, iv injections of 0.1 and 0.3 mg/kg of yohimbine, an alpha 2-adrenoreceptor antagonist, resulted in increased plasma insulin and decreased plasma glucose concentrations in the dog. The use of alpha 2-adrenoreceptor antagonists may be of value in non-insulin-dependent diabetic patients by counteracting the inhibitory influence of endogenous catecholamines. 相似文献
3.
4.
S. J. O'Brien P. Joslin G. L. Smith R. Wolfe N. Schaffer E. Heath J. Ott-Joslin P. P. Rawal K. K. Bhattacharjee J. S. Martenson 《Zoo biology》1987,6(2):99-116
The Asiatic lion (Panthera leo persica) exists in the wild as a single relict population of approximately 250 individuals in the protected Gir Forest Sanctuary in western India. In 1981, a species survival plan (SSP) for the Asiatic lion was established by the American Association of Zoological Parks and Aquariums to manage the 200 + descendants of Asiatic lions in captivity in western zoological facilities. This captive population was derived from seven founders. In order to compare the genetic structure of the Gir Forest population with that of the captive SSP population, a genetic survey of 46 electrophoretic allozyme systems resolved from extracts of lion blood was undertaken by using 29 SSP Asiatic lions and 28 wild-caught or captive-bred lions maintained at the Sakkarbaug Zoo in India but originally derived from the Gir Forest. The Gir lion population was found to be genetically monomorphic at each of 46 allozyme loci. This was in contrast to several African lion (Panthera leo leo) populations, which show moderate levels of allozyme variation at the same loci. The SSP lion population was polymorphic at three allozyme loci (IDHI, TF, and PTI) for alleles that were previously found only in African lion populations. Pedigree analysis of the genetic transmission of these three biochemical loci demonstrated that two of the five primary founder animals of the SSP Asiatic lion population (a breeding pair originally imported from the Trivandrum Zoo in southern India) were descendants of the African subspecies. Three other founder animals were pure Asian. A retrospective SSP pedigree analysis of two morphologic characters (prominent abdominal fold and pairing of infraorbital foramen) that are partially diagnostic for persica vs leo was consistent with this conclusion as well. The implications for the management of small captive populations of threatened species and of the Asiatic lion SSP population are discussed. 相似文献
5.
6.
A firm, mobile, oblong mass was discovered as an incidental finding in the stomach of a chimpanzee (Pan troglodytes) during routine surgery. It was removed and determined to be a trichobezoar. 相似文献
7.
Ronald S. Kaplan June A. Mayor Renee Blackwell Glenn L. Wilson Stephen W. Schaffer 《Molecular and cellular biochemistry》1991,107(1):79-86
The effect of non-insulin-dependent diabetes mellitus (i.e., NIDDM; type 2 diabetes) on the levels of functional mitochondrial anion transport proteins has been determined utilizing
a chemically-induced neonatal model of NIDDM. We hypothesized that moderate insulin deficiency exacerbated by the insulin
resistance, which is characteristic of NIDDM, would cause changes in mitochondrial anion transporter function that were similar
to those we have previously shown to occur in insulin-dependent diabetes mellitus (i.e., IDDM; type 1 diabetes) (Arch. Biochem. Biophys. 280: 181–191, 1990). Our experimental approach consisted of the extraction
of the pyruvate, dicarboxylate and citrate transport proteins from the mitochondrial inner membrane with Triton X-114 using
rat liver mitoplasts (prepared from diabetic and control animals) as the starting material, followed by the functional reconstitution
of each transporter in a proteoliposomal system. This strategy permitted the quantification of the functional levels of these
three transporters in the absence of the complications that arise when such measurements are carried out with intact mitochondria
(or mitoplasts). We found that experimental NIDDM did not cause significant changes in the extractable and reconstitutable
specific (and total) transport activities of the pyruvate, dicarboxylate, and citrate transporters. These results are in marked
contrast to our previous findings obtained using rats with IDDM and negated our hypothesis. The present results, in combination
with our earlier findings, allow us to conclude that insulin plays an important role in the regulation of mitochondrial anion
transporter function. Accordingly, in this model of NIDDM, where the level of insulin is not profoundly deficient, transporter
function is unaltered, whereas in IDDM, where a profound insulinopenia exists, transporter function is altered. Furthermore,
the present studies suggest that in the neonatal model of NIDDM the three mitochondrial transporters investigated are neither
affected by, nor are they the sites of the well documented hepatic post-receptor insulin resistance which is characteristic
of this disease. 相似文献
8.
Staphylococcus aureus counts from swimming pool water were determined by the membrane filtration technique. Water samples were passed through a membrane filter and then put on Baird-Parker media. After incubation, the filters were transferred to nutrient agar, and incubated at 37 degrees C, for 3 h. After removal of the filters, the plates were incubated at 60 degrees C for 2 h. An overlay of toluidine blue agar was added and the plates reincubated for 4 h at 37 degrees C. The formation of thermonuclease correlated with the formation of coagulase, and the results indicated that Staphylococcus aureus could be present in swimming pool water without the presence of either coliform or faecal coliform bacteria. 相似文献
9.
Cloning, sequencing, and functional analysis of oriL, a herpes simplex virus type 1 origin of DNA synthesis. 总被引:69,自引:2,他引:67 下载免费PDF全文
S K Weller A Spadaro J E Schaffer A W Murray A M Maxam P A Schaffer 《Molecular and cellular biology》1985,5(5):930-942
The herpes simplex virus type 1 genome (160 kilobases) contains three origins of DNA synthesis: two copies of oriS located within the repeated sequences flanking the short unique arm (US), and one copy of oriL located within the long unique arm (UL). Precise localization and characterization of oriL have been severely hampered by the inability to clone sequences which contain it (coordinates 0.398 to 0.413) in an undeleted form in bacteria. We report herein the successful cloning of sequences between 0.398 to 0.413 in an undeleted form, using a yeast cloning vector. Sequence analysis of a 425-base pair fragment spanning the deletion-prone region has revealed a perfect 144-base pair palindrome with striking homology to oriS. In a functional assay, the undeleted clone was amplified when functions from herpes simplex virus type 1 were supplied in trans, whereas clones with deletions of 55 base pairs or more were not amplified. 相似文献
10.
Two methods were developed for the assay of substances stimulatory to the nodulation of bean (Phaseolus vulgaris) roots growing from segments of hypocotyl tissue. Coconut water was the chief source of active material, but extracts of cotyledons, hypocotyls and leaves of beans and of horse chestnut fruits were also stimulatory. High concentrations of nitrate improved nodulation both in the presence and absence of coconut water. The ash of coconut water was inactive. Whole alfalfa seedlings formed nodules in the dark when grown in the split medium, but nodulation was not improved by the addition of coconut water. 相似文献