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   175篇
  免费   16篇
  2022年   4篇
  2019年   3篇
  2018年   4篇
  2016年   3篇
  2015年   5篇
  2013年   8篇
  2012年   7篇
  2011年   5篇
  2010年   6篇
  2009年   1篇
  2008年   9篇
  2007年   1篇
  2006年   3篇
  2005年   3篇
  2004年   10篇
  2003年   4篇
  2002年   9篇
  2001年   5篇
  2000年   3篇
  1999年   5篇
  1998年   8篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   4篇
  1990年   1篇
  1989年   3篇
  1988年   4篇
  1987年   1篇
  1986年   7篇
  1985年   1篇
  1984年   1篇
  1983年   3篇
  1982年   3篇
  1981年   2篇
  1980年   3篇
  1979年   4篇
  1978年   3篇
  1977年   7篇
  1976年   1篇
  1975年   4篇
  1974年   4篇
  1973年   5篇
  1972年   3篇
  1971年   2篇
  1970年   3篇
  1969年   3篇
  1968年   1篇
  1967年   3篇
  1965年   1篇
排序方式: 共有191条查询结果,搜索用时 156 毫秒
91.
We studied the effects of ultrasound treatment on an increase of the yield of amino acid mixtures from autolysates of Saccharomyces cerevisiae VKM-Y-2465 grown on ethanol. Adding 2% chloroform (activating agent), autolysis for 5-10 h, and ultrasound treatment of autolysates allowed us to obtain mixtures balanced in lysine, methionine, and tryptophan and containing up to 90% free amino acids.  相似文献   
92.

Background

Seattle Biomedical Research Institute (SBRI) as part of the Leishmania Genome Network (LGN) is sequencing chromosomes of the trypanosomatid protozoan species Leishmania major. At SBRI, chromosomal sequence is annotated using a combination of trained and untrained non-consensus gene-prediction algorithms with ARTEMIS, an annotation platform with rich and user-friendly interfaces.

Results

Here we describe a methodology used to import results from three different protein-coding gene-prediction algorithms (GLIMMER, TESTCODE and GENESCAN) into the ARTEMIS sequence viewer and annotation tool. Comparison of these methods, along with the CODON USAGE algorithm built into ARTEMIS, shows the importance of combining methods to more accurately annotate the L. major genomic sequence.

Conclusion

An improvised and powerful tool for gene prediction has been developed by importing data from widely-used algorithms into an existing annotation platform. This approach is especially fruitful in the Leishmania genome project where there is large proportion of novel genes requiring manual annotation.
  相似文献   
93.
To describe genetic variability and population diversity in domesticated populations of American bison (Bison bison), aurochs (Bison bonasus), and gray Ukrainian cattle (Bos taurus) different variants of DNA fingerprinting technique (utilizing the M13 phage DNA, (TTAGGG)4 synthetic oligonucleotide, and three arbitrary primers as hybridization probes) were used. Several parameters characterizing polymorphism and genetic diversity levels in each population (species) were evaluated on the basis of the profiles obtained. Dendrograms reflecting similarities between individual animals were constructed. Genetic variability of minisatellite and telomeric markers observed in the gray Ukrainian cattle flock was higher than that in aurochs and bisons. Comparison of the intrapopulation similarity (S) and gene diversity (H) indices along with the analysis of clusters in the dendrograms showed that the relatedness between the aurochs individuals was much higher than between the individual animals in the bison and gray Ukrainian cattle flocks. Furthermore, the gray Ukrainian cattle flock was represented by more distant relatives than the bison flock. It is suggested that reduced genetic variability and the appearance of deviant genotype observed in the two bison lines under selection, resulted from close inbreeding and the founder effect. The diagnostic value and efficacy of utilization of different molecular markers for estimation of genetic diversity and relatedness in domesticated animal populations is discussed.  相似文献   
94.
Maintaining the existing genetic diversity in populations is one of the most important measures for species conservation. Some components of this diversity in the bison population of the Prioksko-Terrasny Nature Reserve, including the level of preservation of the founder genetic diversity or the founder genomic equivalent (fge) of the current bison stock and the indices of similarity (mk) and genome uniqueness (gu), as well as their effects on viability of the animals from 1950-1995 were studied. The data obtained were treated and the diversity parameters were calculated with the use of the SPARKS software package. This was performed in collaboration with the Institute for Zoo Biology and Wildlife Research (Berlin, Germany). The results of the analysis indicated that, in breeding groups of the European bison, the fge, mk, and gu values should be maintained at levels higher than 1.30, lower than 40%, and higher than 10%, respectively. When selecting males for specific groups of females, the male gu should be at least 20%, and mk should be lower than 40%.  相似文献   
95.
Kaplin  V. G.  Katyuk  A. I.  Vasin  V. G.  Belousova  O. A.  Vasin  A. V. 《Entomological Review》2019,99(5):580-597
Entomological Review - This paper summarizes data on seasonal development and fecundity of the pea weevil Bruchus pisorum L., its impact on the chemical composition of the pea seeds, damage to...  相似文献   
96.
We tested the effects of injections of small doses of131I (150 μCi) into female rats on brain development in their offspring. The brains of rats whose embryogenesis was influenced by incorporated131I were studied with the use of an immunohistochemical technique (monoclonal antibodies to nuclear antigen of cell proliferation). Single injections of131I in the above dose were shown to noticeably suppress the cell proliferative activity in a few structures of the brain of newborn rats. The most significant drop in the proliferative index in the external layers of the cerebellum was observed after131I injections performed on the 16th day of embryogenesis (when the embryonal thyroid gland begins its functioning).  相似文献   
97.
Capacity for lithotrophic growth coupled to oxidation of reduced sulfur compounds was revealed in an Azospirillum strain, A. thiophilum BV-S T . Oxygen concentration in the medium was the major factor determining the type of energy metabolism (organotrophic or lithotrophic) in the presence of thiosulfate. Under aerobic conditions, metabolism of A. thiophilum BV-ST was organoheterotrophic, with thiosulfate oxidation to tetrathionate resulting from the interaction with reactive oxygen species, mostly H2O2, which was formed in the electron transport chain in the course of oxidation of organic electron donors. Under microaerobic conditions (2 mg/L O2 in liquid medium), A. thiophilum BV-ST carried out lithoheterotrophic (mixotrophic) metabolism; enzymes of the dissimilatory type of sulfur metabolism were responsible for thiosulfate oxidation to tetrathionate and sulfate. Two enzyme systems were found in the cells: thiosulfate dehydrogenase, which catalyzes incomplete oxidation of thiosulfate to tetrathionate and the thiosulfate-oxidizing Sox enzyme complex, which is involved in complete oxidation of thiosulfate to sulfate. The genetic determinant of a Sox complex component in A. thiophilum BV-ST was revealed. The soxB gene was found, and its expression under microaerobic conditions was observed to increase 32-fold compared to aerobic cultivation.  相似文献   
98.
The dynamics of the glutamine synthetase and glutamate dehydrogenase activity was studied during cultivation of Str. antibioticus on media with different contents of glucose and ammonium sulfate. No correlation between the enzymes activity and the levels of oleandomycin production by the mycelium was observed. It was shown that the levels of oleandomycin biosynthesis repression by glucose did not depend on ammonium sulfate concentration in the medium.  相似文献   
99.
Fifty bacterial cultures were isolated from technical oils stored for different periods of time. Twenty out of the fifty strains decomposed technical oils. The bacteria were identified and classified as Bacillus strains. Bacillus subtilis, strains 7 and 10, and B. pumilus, strain 13, isolated from oils MK-8 + 10% Akor-1 and MT-16p as well as from AMG-10 were found to be most active and can be recommended as test cultures to study the resistance of technical oils against bacterial degradation.  相似文献   
100.
Intracellular levels of cyclic AMP (cAMP), adenylate cyclase, and cAMP-phosphodiesterase activities at lag-period, exponential and stationary growth phases of hepatoma 22a were determined. It was shown that the transition of tumour cells from the lag-period to the exponential phase of growth was accompanied by the two-fold decrease of intracellular cAMP level on account of drastic activation of cAMP phosphodiesterase. Subsequently the cAMP level lowered more slowly until the cells entered the stationary phase of growth. In view of the fact that the adenylate cyclase activity failed to change at different growth phases of hepatoma 22a, it seems very proballe that the rise of cAMP phosphodiesterase activity could be a signal for the exit of tumour cells from the lag-period and their entrance into the mitotic cycle.  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