全文获取类型
收费全文 | 359篇 |
免费 | 10篇 |
出版年
2023年 | 2篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 15篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 4篇 |
2013年 | 8篇 |
2012年 | 15篇 |
2011年 | 16篇 |
2010年 | 15篇 |
2009年 | 15篇 |
2008年 | 21篇 |
2007年 | 13篇 |
2006年 | 13篇 |
2005年 | 17篇 |
2004年 | 14篇 |
2003年 | 12篇 |
2002年 | 9篇 |
2001年 | 18篇 |
2000年 | 8篇 |
1999年 | 11篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1995年 | 2篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 10篇 |
1987年 | 4篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 6篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1970年 | 5篇 |
1967年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有369条查询结果,搜索用时 15 毫秒
91.
92.
Yulia V. Gerasimova Petro Yakovchuk Larisa M. Dedkova Sidney M. Hecht Dmitry M. Kolpashchikov 《RNA (New York, N.Y.)》2015,21(10):1834-1843
Mutations in ribosomal RNA (rRNA) have traditionally been detected by the primer extension assay, which is a tedious and multistage procedure. Here, we describe a simple and straightforward fluorescence assay based on binary deoxyribozyme (BiDz) sensors. The assay uses two short DNA oligonucleotides that hybridize specifically to adjacent fragments of rRNA, one of which contains a mutation site. This hybridization results in the formation of a deoxyribozyme catalytic core that produces the fluorescent signal and amplifies it due to multiple rounds of catalytic action. This assay enables us to expedite semi-quantification of mutant rRNA content in cell cultures starting from whole cells, which provides information useful for optimization of culture preparation prior to ribosome isolation. The method requires less than a microliter of a standard Escherichia coli cell culture and decreases analysis time from several days (for primer extension assay) to 1.5 h with hands-on time of ∼10 min. It is sensitive to single-nucleotide mutations. The new assay simplifies the preliminary analysis of RNA samples and cells in molecular biology and cloning experiments and is promising in other applications where fast detection/quantification of specific RNA is required. 相似文献
93.
Two-nanosecond molecular dynamics simulations of the crystal lattice of an active complex of pT160-CDK2 kinase/cyclin A/ATP-Mg2+/substrate were performed. The simulations showed that the structures of the wild-type CDK2 complex and the mutant CDK2 complex involving the substitution G16S-CDK2 corresponding to the yeast substitution G20S-CDC28 differ noticeably and the differences between the structural conformations are most pronounced in the regions that play a key role in the kinase functioning. The results of the computer calculations were used to consider the structural elements that may affect the kinase activity, the regulatory phosphorylation, and the binding of protein kinase with cyclins and substrates. 相似文献
94.
ANDREA FERREIRA DA COSTA PABLO JOSÉ FRANCISCO PENA RODRIGUES MARIA DAS GRAÇAS LAPA WANDERLEY 《Botanical journal of the Linnean Society. Linnean Society of London》2009,159(1):163-181
The species related to Vriesea paraibica (Bromeliaceae, Tillandsioideae) have controversial taxonomic limits. For several decades, this group has been identified in herbarium collections as V. × morreniana, an artificial hybrid that does not grow in natural habitats. The aim of this study was to assess the morphological variation in the V. paraibica complex through morphometric analyses of natural populations. Two sets of analyses were performed: the first involved six natural populations (G1) and the second was carried out on taxa that emerged from the first analysis, but using material from herbarium collections (G2). Univariate ANOVA was used, as well as discriminant analysis of 16 morphometric variables in G1 and 18 in G2. The results of the analyses of the two groups were similar and led to the selection of diagnostic traits of four species. Lengths of the lower and median floral bracts were significant for the separation of red and yellow floral bracts. Vriesea paraibica and V. interrogatoria have red bracts; these two species are differentiated by the widths of the lower and median portions of the inflorescence and by scape length. These structures are larger in the former and smaller in the latter. Of the species with yellow floral bracts, V. eltoniana is distinguished by longer leaf blades and scapes and V. flava is characterized by its shorter sepal lengths. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 163–181. 相似文献
95.
96.
YIT ARN TEH OLIVIER MAZÉAS ALYSSA R. ATWOOD TRIFFID ABEL ROBERT C. RHEW 《Global Change Biology》2009,15(2):330-345
The Arctic tundra has been shown to be a potentially significant regional sink for methyl chloride (CH3Cl) and methyl bromide (CH3Br), although prior field studies were spatially and temporally limited, and did not include gross flux measurements. Here we compare net and gross CH3Cl and CH3Br fluxes in the northern coastal plain and continental interior. As expected, both regions were net sinks for CH3Cl and CH3Br. Gross uptake rates (−793 nmol CH3Cl m−2 day−1 and −20.3 nmol CH3Br m−2 day−1) were 20–240% greater than net fluxes, suggesting that the Arctic is an even greater sink than previously believed. Hydrology was the principal regulator of methyl halide flux, with an overall trend towards increasing methyl halide uptake with decreasing soil moisture. Water table depth was one of the best predictors of net and gross uptake, with uptake increasing proportionately with water table depth. In drier areas, gross uptake was very high, averaging −1201 nmol CH3Cl m−2 day−1 and −34.9 nmol CH3Br m−2 day−1; in flooded areas, gross uptake was significantly lower, averaging −61 nmol CH3Cl m−2 day−1 and −2.3 nmol CH3Br m−2 day−1. Net and gross uptake was greater in the continental interior than in the northern coastal plain, presumably due to drier inland conditions. Within certain microtopographic features (low‐ and high‐centered polygons), uptake rates were positively correlated with soil temperature, indicating that temperature played a secondary role in methyl halide uptake. Incubations suggested that the inverse relationship between water content and methyl halide uptake was the result of mass transfer limitation in saturated soils, rather than because of reduced microbial activity under anaerobic conditions. These findings have potential regional significance, as the Arctic is expected to become warmer and drier due to anthropogenic climate forcing, potentially enhancing the Arctic sink for CH3Cl and CH3Br. 相似文献
97.
T. A. Revina G. V. Kladnitskaya N. G. Gerasimova E. L. Gvozdeva T. A. Valueva 《Biochemistry. Biokhimii?a》2010,75(1):36-40
A protein of 22 kDa designated as PKTI-22 was isolated from potato tubers (Solanum tuberosum L., cv. Istrinskii) and purified to homogeneity using CM-Sepharose CL-6B ion-exchange chromatography. The protein efficiently
suppressed the activity of trypsin, affected chymotrypsin less, and did not affect subtilisin Carlsberg. The N-terminal sequence
of PKTI-22 (20 amino acid residues) was found to be highly homologous with the amino acid sequences of the potato Kunitz-type
proteinase inhibitors of group B (PKPI-B) that were aligned from the corresponding gene sequences and was identical to the
sequence (from the 2nd to the 20th residue) of the recombinant protein PKPI-B10. These data together with the observed similarity
of the properties of two proteins indicate that the PKTI-22 protein is encoded by the PKPI-B10 gene. 相似文献
98.
S. V. Gerasimova Ya. S. Kolodyazhnaya S. E. Titov A. V. Romanova V. S. Koval’ A. V. Kochetov V. K. Shumnyi 《Russian Journal of Genetics》2010,46(7):890-893
The Medicago truncatula ornithine aminotransferase cDNA was cloned under the potent constitutive 35S RNA promoter of the cauliflower mosaic virus
and transferred into the genome of tobacco Nicotiana tabacum SR1 plants. Transformed tobacco plants grew better in salinity stress, but did not differ in proline content under normal
or stress conditions from control plants. It was assumed that the role of ornithine aminotransferase in the molecular mechanisms
of stress resistance is not associated with additional proline synthesis. 相似文献
99.
Research laboratories studying the genetics of companion animals have no database tools specifically designed to aid in the
management of the many kinds of data that are generated, stored and analyzed. We have developed a relational database, "DOG-SPOT,"
to provide such a tool. Implemented in MS-Access, the database is easy to extend or customize to suit a lab's particular needs.
With DOG-SPOT a lab can manage data relating to dogs, breeds, samples, biomaterials, phenotypes, owners, communications, amplicons,
sequences, markers, genotypes and personnel. Such an integrated data structure helps ensure high quality data entry and makes
it easy to track physical stocks of biomaterials and oligonucleotides. 相似文献
100.