全文获取类型
收费全文 | 306篇 |
免费 | 41篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 9篇 |
2016年 | 4篇 |
2015年 | 9篇 |
2014年 | 9篇 |
2013年 | 18篇 |
2012年 | 17篇 |
2011年 | 21篇 |
2010年 | 15篇 |
2009年 | 15篇 |
2008年 | 14篇 |
2007年 | 17篇 |
2006年 | 16篇 |
2005年 | 12篇 |
2004年 | 7篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 8篇 |
1995年 | 2篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 7篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1971年 | 6篇 |
1968年 | 4篇 |
1965年 | 2篇 |
1964年 | 2篇 |
排序方式: 共有347条查询结果,搜索用时 29 毫秒
101.
Twenty‐seven polymorphic microsatellite markers were isolated from red clover (Trifolium pratense). Allelic variability and cross‐species amplification were assessed on 24 red clover and eight white clover (Trifolium repens) genotypes. The number of alleles detected in red clover ranged from two to 25. Observed and expected heterozygosities were high with average values of 0.71 and 0.88, respectively. Five of the 27 loci were also successfully amplified from white clover, where two to 13 alleles were detected. These highly polymorphic microsatellite loci provide powerful tools for population genetic studies as well as for marker‐assisted selection in this important forage legume species. 相似文献
102.
Investigating lipid composition effects on the mechanosensitive channel of large conductance (MscL) using molecular dynamics simulations 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Biophysical journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Previous experimental work has shown that the functional properties of the mechanosensitive channel of large conductance (MscL) are affected by variations in lipid composition. Here, we utilize molecular dynamics simulations of Mycobacterium tuberculosis MscL to investigate such lipid composition effects on a molecular level. In particular, two sets of simulations were performed. In the first, trajectories using lipids with different headgroups (phosphatidylcholine and phosphatidylethanolamine) were compared. Protein-lipid interactions were clearly altered by the headgroup changes, leading to conformational differences in the C-terminal region of M. tuberculosis MscL. In the second set of simulations, lipid tails were gradually shortened, thinning the membrane over a molecular dynamics trajectory. These simulations showed evidence of hydrophobic matching between MscL and the lipid membrane, as previously proposed. For all simulations, protein-lipid interaction energies in the second transmembrane region were correlated to mutagenic data, emphasizing the importance of lipid interactions for proper MscL function. 相似文献
103.
ERWIN REINWALD CLAUDIA HEIDRICH HANS-J
RG RISSE 《The Journal of eukaryotic microbiology》1984,31(2):300-306
Tritiated leucine, glucosamine, mannose, and galactose were incorporated into the variant specific surface glycoprotein (VSG) of Trypanosoma congolense in vitro. The uptake of the precursors is shown by SDS-polyacrylamide electrophoresis and fluorography, by assay of the radioactivity in immunoprecipitates obtained with specific antisera, and by the isolation of the labeled antigens by affinity chromatography on concanavalin A-sepharose and isoelectric focusing. The in vitro labeled VSG exhibits the same degree of microheterogeneity as that observed in the VSG isolated from trypanosomes grown in animals. Analysis of the incorporated sugars after hydrolysis of the glycoprotein showed that glucosamine and mannose were utilized in biosynthesis of the carbohydrate moiety directly whereas galactose was converted possibly to other intermediates before being incorporated into the antigen. Tunicamycin completely prevented the incorporation of the radiolabeled sugars into the surface glycoprotein. The unglycosylated VSG with a molecular weight of 47 kDa had completely lost its size heterogeneity. 相似文献
104.
105.
A.L. Jenkins R.S. Youngquist R.G. Elmore D.J. Kesler H.A. Garverick C.J. Bierschwal 《Theriogenology》1977,7(4):251-257
Two cases of bovine fetal mummification were treated with a single intramuscular injection of 500 μg cloprostenol. Plasma progesterone levels fell rapidly within 24 hours following injection from a mean level of 10.45 ng/ml to 1.05 ng/ml. Extradiol-17β levels were variable and low () during the 120-hour postinjection sampling period. The mummies were delivered at 104 and 120 hours postinjection. Both were expelled into the vagina and traction was required to complete removal from the genital tract. No adverse reactions which could be attributed to treatment were observed. 相似文献
106.
Dairy cows known to have ovarian cysts were assigned to receive either sterile water or 100 μg GnRH (5 cows/group). The ovaries were removed 9 to 13 days post-treatment and prepared for histologic study. The cyst walls of ovaries removed from cows following GnRH treatment were 2 to 15 times thicker than those from cows treated with water due to apparent luteinization of cells of theca interna. Following GnRH treatment, the cells in the outermost portion of the theca interna exhibited the greatest morphologic evidence of secretory activity whereas the innermost zone was hyalinized due to poor blood supply. The luteal cells in ovarian cystic cows treated with GnRH were similar to the small luteal cells in normal corpora lutea. In summary, GnRH treatment of cows with ovarian cysts appeared to induce luteinization of the cells in the outermost portion of the theca interna. 相似文献
107.
The SNRPN gene is known to be expressed exclusively from the paternal allele and to map to the critical region for the neurobehavioral
disorder, Prader-Willi syndrome (PWS). As a means to investigate the mechanism of imprinting for the SNRPN gene, we have sought
to recapitulate the imprinted expression of the endogenous gene. Using an 85-kb murine Snrpn clone, containing 33 kb of 5′ and 30 kb of 3′ flanking DNA, we obtained two intact transgenic lines. One line, containing
two copies of the Snrpn transgene, recapitulated the imprinted expression pattern of the endogenous locus, whereas the other transgenic line, containing
a single copy, was expressed upon both maternal and paternal inheritance. This suggests that a 6.6-kb region of maternal-specific
DNA methylation that we have identified may be sufficient to confer imprinted expression, but not in a copy-number independent
manner. Finally, we produced five lines of transgenic mice using a 76-kb human SNRPN clone containing 45 kb and 7 kb of 5′
and 3′ flanking DNA, respectively. We found all the lines were expressed upon both maternal and paternal inheritance, regardless
of copy number, suggesting that the imprinting machinery in mouse and human may have diverged.
Received: 11 November 1998 / Accepted: 29 January 1999 相似文献
108.
Nonparametric inference in multivariate mixtures 总被引:1,自引:0,他引:1
109.
110.
To ascertain if a correlation exists between circulating plasma progesterone levels and rectal temperatures in swine, 10 mixed breed postpubertal ovariectomized gilts were treated with sesame oil containing 500 mg progesterone IM or with saline IM. The average daily rectal temperatures were not correlated with the circulating plasma progesterone levels. Rectal temperature observations do not provide a useful indication of corpus luteum activity in swine. 相似文献