全文获取类型
收费全文 | 1159篇 |
免费 | 26篇 |
专业分类
1185篇 |
出版年
2021年 | 11篇 |
2020年 | 10篇 |
2019年 | 16篇 |
2018年 | 27篇 |
2017年 | 22篇 |
2016年 | 22篇 |
2015年 | 18篇 |
2014年 | 29篇 |
2013年 | 46篇 |
2012年 | 46篇 |
2011年 | 57篇 |
2010年 | 36篇 |
2009年 | 34篇 |
2008年 | 43篇 |
2007年 | 34篇 |
2006年 | 39篇 |
2005年 | 41篇 |
2004年 | 39篇 |
2003年 | 24篇 |
2002年 | 43篇 |
2001年 | 57篇 |
2000年 | 35篇 |
1999年 | 28篇 |
1998年 | 17篇 |
1997年 | 14篇 |
1996年 | 6篇 |
1994年 | 10篇 |
1992年 | 25篇 |
1991年 | 27篇 |
1990年 | 22篇 |
1989年 | 32篇 |
1988年 | 24篇 |
1987年 | 18篇 |
1986年 | 26篇 |
1985年 | 19篇 |
1984年 | 16篇 |
1983年 | 13篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1974年 | 14篇 |
1973年 | 10篇 |
1972年 | 18篇 |
1971年 | 6篇 |
1970年 | 8篇 |
1969年 | 7篇 |
1968年 | 7篇 |
1967年 | 13篇 |
1965年 | 6篇 |
排序方式: 共有1185条查询结果,搜索用时 0 毫秒
101.
T.?P.?TourovaEmail author E.?M.?Spiridonova I.?A.?Berg B.?B.?Kuznetsov D.?Yu.?Sorokin 《Microbiology》2005,74(3):321-328
Fragments of genes of the “green-like” form I ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) of eight species of haloalkaliphilic obligately autotrophic sulfur-oxidizing bacteria of the genus Thioalkalivibrio have been revealed and sequenced using previously developed oligonucleotide primers. The data obtained are used for the construction of phylogenetic trees on the basis of nucleotide sequences of RuBisCO genes and their conceptual translations into amino acid sequences. Comparative analysis of the 16S rRNA and RuBisCO gene trees reveals discrepancies between their topologies. According to a RuBisCO gene analysis, the genus Thioalkalivibrio is not monophyletic, and its inner divergence conforms to the significant morphological differences observed between the species. Presumably, horizontal (interspecies) gene transfer was involved in the evolution of the genus Thioalkalivibrio.__________Translated from Mikrobiologiya, Vol. 74, No. 3, 2005, pp. 378–386.Original Russian Text Copyright © 2005 by Tourova, Spiridonova, Berg, Kuznetsov, Sorokin. 相似文献
102.
Kuznetsov AN Turkovskiĭ II Paramonov BA Kharin VN Kuznetsova NV Volkova IA 《Biofizika》2004,49(4):727-731
The complex dielectric permittivity of salt solutions with positive and negative salvation as well as healthy and cicatricially changed human skin in situ at the frequencies of 42 and 56.6 GHz was measured. The relation between the dielectric characteristics of water and diluted salt solutions and changes in their structural organization conditioned by different temperatures of samples and the type of salvation of electrolytes was studied. The differences in the dielectric characteristics of healthy and cicatricially changed skin are interpreted in terms of the dependence of the structural organization of interstitial fluids on the morphological and functional state of biological tissues. 相似文献
103.
Spiridonova EM Berg IA Kolganova TV Ivanovskiĭ RN Kuznetsov BB Turova TP 《Mikrobiologiia》2004,73(3):377-387
Based on the analysis of GenBank nucleotide sequences of the cbbL and cbbM genes, coding for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPC), the key enzyme of the Calvin cycle, a primer system was designed that allows about 800-bp-long fragments of these genes to be PCR-ampliflied in various photo- and chemotrophic bacteria. The efficiency of the designed primer system in detection of RuBPC genes was demonstrated in PCR with DNA of taxonomically diverse bacteria possessing RuBPC genes with a known primary structure. Nucleotide sequences of RuBPC gene fragments of bacteria belonging to the genera Acidithiobacillus. Ectothiorhodospira, Magnetospirillum, Methylocapsa, Thioalkalispira, Rhodobacter, and Rhodospirillum were determined to be deposited with GenBank and to be translated into amino acid sequences and subjected to phylogenetic analysis. 相似文献
104.
8-Oxoguanine-DNA glycosylases play a key role in the repair of oxidatively damaged DNA. The Escherichia coli formamidopyrimidine-DNA glycosylase (Fpg) and human 8-oxoguanine-DNA glycosylase (hOGG1) are DNA base excision repair enzymes that catalyze the removal of 7,8-dihydro-8-oxoguanine (oxoG) residue, and cleave DNA strand. Specific contacts between DNA phosphate groups and amino acids from active centers of these enzymes play a significant role in DNA-protein interactions. In order to design new non-hydrolyzable substrate analogs of Fpg and hOGG1 for structural studies modified DNA duplexes containing pyrophosphate or OEt-substituted pyrophosphate internucleotide (SPI) groups near the damage were tested. We showed that enzymes recognize and specifically bind to DNA duplexes obtained. The mechanism of incision of oxoG by the Fpg and hOGG1 was determined. We revealed that both enzymes were not able to excise the oxoG residue from DNA containing modified phosphates immediately 3' to the oxoG. In contrast, Fpg and hOGG1 effectively incise DNA duplex carrying analogous phosphate modifications 5' to the oxoG. Non-cleavable oxoG-containing DNA duplexes bearing pyrophosphate or substituted pyrophosphate groups immediately 3' to the oxoG are specific inhibitors for both 8-oxoguanine-DNA glycosylases and can be used for structural studies of complexes comprising a oxoG-containing DNA bound to catalytically active wild-type enzymes as well as their pro- and eucaryotic homologs. 相似文献
105.
A. M. Mokhamed G. N. Raldugina V. P. Kholodova Vl. V. Kuznetsov 《Russian Journal of Plant Physiology》2006,53(5):649-655
Physiological mechanisms of two rape (Brassica napus L.) genotype adaptation to chlorine salinity were investigated. The plants of two cultivars (Olga and Westar) differing in
salt tolerance were grown in the pots filled with Perlite on the Hoagland and Snyder’s medium under controlled conditions.
At a stage of 3–4 true leaves, the plants experienced 7-day-long salinity induced by a single addition of NaCl to the nutrient
medium in order to attain desired final salt concentration (from 50 to 400 mM). The obtained results showed that a greater
salt tolerance of cv. Olga plants (as compared with cv. Westar) could be accounted for by a capability of their root cells
to uptake water under high salinity (300–400 mM NaCl), which is evident from a greater content of water in the tissues of
cv. Olga. This was ensured by a sharp fall of the osmotic potential of the cellular contents (down to −2.3 MPa) at a low water
potential of nutrient solution owing to more active uptake of Na+ (57–61 μeq/g fr wt) and K+ (210–270 μeq/g fr wt) as well as active accumulation of proline (30–50 μmol/g fr wt). The latter is caused by a reduced activity
of proline dehydrogenase and retarded degradation of this osmolyte. It is important that, in contrast to less tolerant genotype,
the rape plants of salt-resistant cultivar were able to maintain the K+/Na+ ratio at a rather high level at salinity of different degree, which made it possible to preserve ionic homeostasis under
adverse conditions.
Original Russian Text ? A.M. Mokhamed, G.N. Raldugina, V.P. Kholodova, Vl.V. Kuznetsov, 2006, published in Fiziologiya Rastenii,
2006, Vol. 53, No. 5, pp. 732–738. 相似文献
106.
Vl. V. Kuznetsov N. L. Radyukina N. I. Shevyakova 《Russian Journal of Plant Physiology》2006,53(5):583-604
In this review, we consider recent advances in the study of the multifaceted biological role of polyamines, primarily under stress conditions, discuss molecular mechanisms controlling their anabolism, catabolism, and transport, and also the regulation of gene expression for key enzymes of their biosynthesis and degradation. To understand the place and role of polyamines in plant adaptation, we focus the data concerning gene expression obtained by modern physicochemical methods on mutant and transgenic plants and also on natural stress-tolerant species manifesting a high tolerance to salinity, drought, and other abiotic factors. 相似文献
107.
108.
Zharikova NV Markusheva TV Galkin EG Korobov VV Zhurenko EIu Sitdikova LR Kolganova TV Kuznetsov BB Turova TP 《Prikladnaia biokhimiia i mikrobiologiia》2006,42(3):292-297
A new strain that degrades the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) was isolated from soil, which was exposed to factors related to the petrochemical industry. According to its physiological, biochemical, cultural, and morphological traits, together with the sequence of the 16S rRNA gene, the strain was identified as Raoultella planticola 33-4ch. The strain could consume 2,4,5-T as a sole source of carbon and energy. The amount of 2,4,5-T in the culture medium decreased by 51% after five days of incubation. Raoultella planticola 33-4ch consumes 2,4,5-T to produce 4-chlorophenoxyacetic, phenoxyacetic, and 3-methyl-2,6-dioxo-4-hexenoic acids. 相似文献
109.
MOTIVATION: Most biological sequences contain compositionally biased segments in which one or more residue types are significantly overrepresented. The function and evolution of these segments are poorly understood. Usually, all types of compositionally biased segments are masked and ignored during sequence analysis. However, it has been shown for a number of proteins that biased segments that contain amino acids with similar chemical properties are involved in a variety of molecular functions and human diseases. A detailed large-scale analysis of the functional implications and evolutionary conservation of different compositionally biased segments requires a sensitive method capable of detecting user-specified types of compositional bias. RESULTS: We present BIAS, a novel sensitive method for the detection of compositionally biased segments composed of a user-specified set of residue types. BIAS uses the discrete scan statistics that provides a highly accurate correction for multiple tests to compute analytical estimates of the significance of each compositionally biased segment. The method can take into account global compositional bias when computing analytical estimates of the significance of local clusters. BIAS is benchmarked against SEG, SAPS and CAST programs. We also use BIAS to show that groups of proteins with the same biological function are significantly associated with particular types of compositionally biased segments. 相似文献
110.
ATP production in mitochondria depends on the nuclear spin and magnetic moment of Mg2+ ion in creatine kinase and ATPase. Consequently, the enzymatic synthesis of ATP is an ion-radical process and depends on the external magnetic field and microwave fields that control the spin states of ion-radical pairs and influence the ATP synthesis. The chemical mechanism of ATP synthesis and the origin of biological effects of electromagnetic (microwave) fields are discussed. 相似文献