全文获取类型
收费全文 | 1178篇 |
免费 | 22篇 |
专业分类
1200篇 |
出版年
2021年 | 8篇 |
2020年 | 9篇 |
2019年 | 13篇 |
2018年 | 17篇 |
2017年 | 17篇 |
2016年 | 17篇 |
2015年 | 11篇 |
2014年 | 16篇 |
2013年 | 51篇 |
2012年 | 34篇 |
2011年 | 32篇 |
2010年 | 23篇 |
2009年 | 25篇 |
2008年 | 33篇 |
2007年 | 40篇 |
2006年 | 21篇 |
2005年 | 38篇 |
2004年 | 39篇 |
2003年 | 31篇 |
2002年 | 51篇 |
2001年 | 30篇 |
2000年 | 31篇 |
1999年 | 23篇 |
1997年 | 7篇 |
1992年 | 30篇 |
1991年 | 37篇 |
1990年 | 36篇 |
1989年 | 29篇 |
1988年 | 43篇 |
1987年 | 31篇 |
1986年 | 44篇 |
1985年 | 35篇 |
1984年 | 28篇 |
1983年 | 19篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1980年 | 10篇 |
1979年 | 19篇 |
1978年 | 21篇 |
1977年 | 13篇 |
1976年 | 11篇 |
1975年 | 8篇 |
1974年 | 13篇 |
1973年 | 16篇 |
1972年 | 13篇 |
1971年 | 19篇 |
1969年 | 8篇 |
1967年 | 10篇 |
1966年 | 7篇 |
1965年 | 6篇 |
排序方式: 共有1200条查询结果,搜索用时 15 毫秒
31.
Smirnov V. P. Samokhin A. A. Gavrikov A. V. Kuzmichev S. D. Usmanov R. A. Vorona N. A. 《Plasma Physics Reports》2019,45(5):454-458
Plasma Physics Reports - A new concept of plasma separation of spent nuclear fuel components in a variable-cross-section chamber with a nonuniform magnetic field is proposed. Numerical simulation... 相似文献
32.
Makarov I. O. Klyuev D. A. Smirnov V. F. Smirnova O. N. Anikina N. A. Dikareva N. V. 《Microbiology》2019,88(1):72-78
Microbiology - Effect of low-frequency pulsed magnetic field and of low-intensity laser radiation on mycelial fungi actively degrading various polymer materials was studied. These factors had a... 相似文献
33.
Caroline Comte Yann Tonin Anne-Marie Heckel-Mager Abdeldjalil Boucheham Alexandre Smirnov Karine Auré Anne Lombès Robert P. Martin Nina Entelis Ivan Tarassov 《Nucleic acids research》2013,41(1):418-433
Mitochondrial mutations, an important cause of incurable human neuromuscular diseases, are mostly heteroplasmic: mutated mitochondrial DNA is present in cells simultaneously with wild-type genomes, the pathogenic threshold being generally >70% of mutant mtDNA. We studied whether heteroplasmy level could be decreased by specifically designed oligoribonucleotides, targeted into mitochondria by the pathway delivering RNA molecules in vivo. Using mitochondrially imported RNAs as vectors, we demonstrated that oligoribonucleotides complementary to mutant mtDNA region can specifically reduce the proportion of mtDNA bearing a large deletion associated with the Kearns Sayre Syndrome in cultured transmitochondrial cybrid cells. These findings may be relevant to developing of a new tool for therapy of mtDNA associated diseases. 相似文献
34.
The effect of membrane composition on the hemostatic balance 总被引:6,自引:0,他引:6
The phospholipid composition requirements for optimal prothrombin activation and factor Va inactivation by activated protein C (APC) anticoagulant were examined. Vesicles composed of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) supported factor Va inactivation relatively well. However, optimal factor Va inactivation still required relatively high concentrations of phosphatidylserine (PS). In addition, at a fixed concentration of phospholipid, PS, and APC, vesicles devoid of PE never attained a rate of factor Va inactivation achievable with vesicles containing PE. Polyunsaturation of any vesicle component also contributed significantly to APC inactivation of factor Va. Thus, PE makes an important contribution to factor Va inactivation that cannot be mimicked by PS. In the absence of polyunsaturation in the other membrane constituents, this contribution was dependent upon the presence of both the PE headgroup per se and unsaturation of the 1,2 fatty acids. Although PE did not affect prothrombin activation rates at optimal PS concentrations, PE reduced the requirement for PS approximately 10-fold. The Km(app) for prothrombin and the Kd(app) for factor Xa-factor Va decreased as a function of increasing PS concentration, reaching optimal values at 10-15% PS in the absence of PE but only 1% PS in the presence of PE. Fatty acid polyunsaturation had minimal effects. A lupus anticoagulant immunoglobulin was more inhibitory to both prothrombinase and factor Va inactivation in the presence of PE. The degree of inhibition of APC was significantly greater and much more dependent on the phospholipid composition than that of prothrombinase. Thus, subtle changes in the phospholipid composition of cells may control procoagulant and anticoagulant reactions differentially under both normal and pathological conditions. 相似文献
35.
Different mechanisms of genetic sex determination in birds are considered. Special emphasis is placed on the influence of external factors (reduction of estrogen synthesis, inactivation of DNA methylases) on expression of key sex determining genes. The possibility of sex inversion in domestic chicken by aromatase inhibition, genomic DNA demethylation, and the effect of estrogen analogs on estrogen receptors was demonstrated. The results of these effects were analyzed and their effect on the development of gonads in one-day embryos was demonstrated. A suggestion on earlier aromatase activity in chicken embryos, weak effect of DNA demethylation with 5-azacytidine, and different mechanisms of the effect of estrogens and their analogs (tamoxifen) on the gonad development in chicken was made. 相似文献
36.
M. R. Khaitov A. R. Gaisina I. P. Shilovskiy V. V. Smirnov G. V. Ramenskaia A. A. Nikonova R. M. Khaitov 《Biochemistry. Biokhimii?a》2018,83(1):13-25
Interleukin-33 (IL-33) belongs to the IL-1 cytokine family and plays an important role in modulating immune system by inducing Th2 immune response via the ST2 membrane receptor. Epithelial cells are the major producers of IL-33. However, IL-33 is also secreted by other cells, e.g., bone marrow cells, dendritic cells, macrophages, and mast cells. IL-33 targets a broad range of cell types bearing the ST2 surface receptor. Many ST2-positive cells, such as Th2 cells, mast cells, basophils, and eosinophils, are involved in the development of allergic bronchial asthma (BA). This suggests that IL-33 directly participates in BA pathogenesis. Currently, the role of IL-33 in pathogenesis of inflammatory disorders, including BA, has been extensively investigated using clinical samples collected from patients, as well as asthma animal models. In particular, numerous studies on blocking IL-33 and its receptor by monoclonal antibodies in asthma mouse model have been performed over the last several years; IL-33-and ST2-deficient transgenic mice have also been generated. In this review, we summarized and analyzed the data on the role of IL-33 in BA pathogenesis and the prospects for creating new treatments for BA. 相似文献
37.
E. V. Borvinskaya I. V. Sukhovskaya A. A. Kochneva O. B. Vasilyeva M. A. Nazarova L. P. Smirnov N. N. Nemova 《Contemporary Problems of Ecology》2016,9(2):195-202
The base levels and seasonal variability of ethoxyresorufin-O-deethylase (EROD) activity, glutathione-S-transferase (GST) activity, reduced glutathione concentration (GSH) and phospholipids concentration (PhL) of Coregonus lavaretus (Linnaeus, 1758) and Coregonus muksun (Pallas, 1814) were investigated. The relationships between this biochemical markers, hepatosomatic index and seasonal growth were also examined. 相似文献
38.
Transposition of ampicillin Tn1 transposon is repressed under normal conditions and occurs with low frequency (10(-4) per cell). Treatment of Escherichia coli cells with 22 c+mytomycin C, nitrosoguanidine and UV light induced transposition of Tn1 into different replicons. The degree of induction depended upon the strain of bacteria and the replicon which the transposon was inserted into. Mutation recA did not influence spontaneous translocation of the transposon but fully repressed induction of transposition during the period of mutagen treatment. In the present paper, the connection of inducible transposition process with the recA and lexA inducible functions of E. coli is discussed. 相似文献
39.
S V Davenis A P Markov A V Golubev G B Smirnov 《Molekuliarnaia genetika, mikrobiologiia i virusologiia》1988,(9):14-17
The affect of mutations in chromosomal genes determining the realization of RecBC and RecF pathways of recombination in E. coli K12 on the frequency of transposon Tn5 precise excision from the genome of the conjugative plasmid pNM1 has been demonstrated. The pNM1 plasmid is a derivative of R100.1 and differs from the latter in the presence of Tn5 inactivating the tet gene of transposon Tn10. 相似文献
40.
N. N. Smirnov 《Hydrobiologia》1967,30(3-4):555-571
Summary Young and adult males of 11 species of Chydoridae are studied, their figures being published here (fig. 1–15). The necessity is stressed to distinguish young forms of males and gynandromorphic individuals.Pleuroxus balatonicus is considered to be described from the population ofPleuroxus unicatus having under Balaton Lake conditions retarded transformation of young males into adult form, and accordingly having unusually numerous young males. \qO\qs\qn\qo\qv\qn\qy\ye \qr\ye\qz\qu\ql\Qj\qt\qa\qt\qy 11 (. 1–15). . , Pleuroxus uncinatus , Pleuroxus balatonicus. 相似文献