全文获取类型
收费全文 | 332篇 |
免费 | 22篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 13篇 |
2014年 | 19篇 |
2013年 | 36篇 |
2012年 | 15篇 |
2011年 | 13篇 |
2010年 | 18篇 |
2009年 | 10篇 |
2008年 | 10篇 |
2007年 | 15篇 |
2006年 | 11篇 |
2005年 | 16篇 |
2004年 | 12篇 |
2003年 | 18篇 |
2002年 | 22篇 |
2001年 | 16篇 |
2000年 | 17篇 |
1999年 | 9篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1965年 | 2篇 |
排序方式: 共有354条查询结果,搜索用时 15 毫秒
1.
Characterization of 3''----5'' exonuclease associated with DNA polymerase of silkworm nuclear polyhedrosis virus. 总被引:2,自引:1,他引:1 下载免费PDF全文
V S Mikhailov K A Marlyev J O Ataeva P K Kullyev A M Atrazhev 《Nucleic acids research》1986,14(9):3841-3857
3'----5' Exonuclease specific for single-stranded DNA copurified with DNA polymerase of nuclear polyhedrosis virus of silkworm Bombyx mori (BmNPV Pol). BmNPV Pol has no detectable 5'----3' exonuclease activity on single-stranded or duplex DNA. Analysis of the products of 3'----5' exonucleolytic reaction showed that deoxynucleoside monophosphates were released during the hydrolysis of single-stranded DNA. The exonuclease activity cosedimented with the polymerase activity during ultracentrifugation of BmNPV Pol in glycerol gradient. The polymerase and the exonuclease activities of BmNPV Pol were inactivated by heat with nearly identical kinetics. The mode of the hydrolysis of single-stranded DNA by BmNPV Pol-associated exonuclease was strictly distributive. The enzyme dissociated from single-stranded DNA after the release of a single dNMP and then reassociated with a next polynucleotide being degradated. 相似文献
2.
mtDNA diversity in rhesus monkeys reveals overestimates of divergence time and paraphyly with neighboring species 总被引:4,自引:0,他引:4
Reconstructions of the human-African great ape phylogeny by using
mitochondrial DNA (mtDNA) have been subject to considerable debate. One
confounding factor may be the lack of data on intraspecific variation. To
test this hypothesis, we examined the effect of intraspecific mtDNA
diversity on the phylogenetic reconstruction of another Plio- Pleistocene
radiation of higher primates, the fascicularis group of macaque (Macaca)
monkey species. Fifteen endonucleases were used to identify 10 haplotypes
of 40-47 restriction sites in M. mulatta, which were compared with similar
data for the other members of this species group. Interpopulational,
intraspecific mtDNA diversity was large (0.5%- 4.5%), and estimates of
divergence time and branching order incorporating this variation were
substantially different from those based on single representatives of each
species. We conclude that intraspecific mtDNA diversity is substantial in
at least some primate species. Consequently, without prior information on
the extent of genetic diversity within a particular species, intraspecific
variation must be assessed and accounted for when reconstructing primate
phylogenies. Further, we question the reliability of hominoid mtDNA
phylogenies, based as they are on one or a few representatives of each
species, in an already depauperate superfamily of primates.
相似文献
3.
Zenchenko A. A. Drenichev M. S. Il’icheva I. A. Mikhailov S. N. 《Molecular Biology》2021,55(6):786-812
Molecular Biology - The emergence of new viruses and resistant strains of pathogenic microorganisms has become a powerful stimulus in the search for new drugs. Nucleosides are a promising class of... 相似文献
4.
Mikko Oivanen Ekaterina V. Efimtseva Sergey N. Mikhailov 《Nucleosides, nucleotides & nucleic acids》2013,32(8):1325-1331
Abstract The first-order rate constants for hydrolysis of 3′-C-methyluridylyl(2′,5′)- and -(3′,5′)adenosine and the corresponding native dinucleoside monophosphates (2′,5′- and 3′,5′-UpA) have been determined as a function of hydroxide-ion concentration (0.025 - 7 M) at 25°C. In addition to the effects on the hydrolytic stability of the compounds, the effects of the 3′-C-methyl substitution on the kinetically determined pK a values for the sugar hydroxyls of the undine moiety are discussed. 相似文献
5.
Andrei A. Rodionov Ekaterina V. Efimtseva Sergey N. Mikhailov 《Nucleosides, nucleotides & nucleic acids》2013,32(4-5):623-624
Abstract The first synthesis of O-β-D-ribofuranosyl-(1″-2′)-adenosine-5″-O-phosphate starting from protected 2′-O-β-D-ribofuranosyladenosine has been performed. 相似文献
6.
Sergey N. Mikhailov Erik De Clercq Piet Herdewijn 《Nucleosides, nucleotides & nucleic acids》2013,32(7-8):1323-1334
Abstract The previously developed method for the preparation of 2′-O-D-ribofuranosyl-nucleosides is extended to ribosylation of 2′-deoxynucleosides. The scope and limitations of this reaction are discussed. 相似文献
7.
Adameyko K. I. Kravchuk O. I. Finoshin A. D. Bonchuk A. N. Georgiev A. A. Mikhailov V. S. Gornostaev N. G. Mikhailov K. V. Bacheva A. V. Indeykina M. I. Bugrova A. E. Gazizova G. R. Kozlova O. S. Gusev O. A. Shagimardanova E. I. Lyupina Y. V. 《Molecular Biology》2020,54(3):416-420
Molecular Biology - The iron-containing protein neuroglobin (Ngb) involved in the transport of oxygen is generally considered the precursor of all animal globins. In this report, we studied the... 相似文献
8.
Enantiornithes is the most speciose clade of Cretaceous birds, but many taxa are known from isolated postcranial skeletons. Two embryonic enantiornithine bird skeletons of Gobipipus reshetovi gen. et sp. nov. from the Upper Cretaceous (Campanian) Barun Goyot Formation of the Gobi Desert in Mongolia provide new insights into the anatomy, radiation, and mode of development of early avialans. In recent times, both enantiornithine and ornithuromorph birds are known from the Barun Goyot Formation as well as from the Djadokhta and Nemegt Formations. The 80-million-year-old Gobipipus skeletons encased within eggshells shows several features characteristic of enantiornithine birds. The wing skeleton and shoulder girdle show morphological features indicating that Gobipipus achieved sophisticated powered flight. Gobipipus reshetovi gen. et sp. nov. is quite distinct from the sympatric enantiornithine species Gobipteryx minuta from the same strata in many anatomical features. Phylogenetic analysis of 26 avialan ingroup taxa based on distribution of 202 characters indicate that Gobipipus is a basal member of enantiornithine birds along with Confuciusornis and shares more characters with ornithuromorphs than previously recognized. The embryonic nature of Gobipipus specimens sheds new light on the developmental history of enantiornithine birds. The well-ossified bones of the fore- and hind limbs, and fusion of many skeletal elements indicate a precocial mode of development in Gobipipus. Apparently Gobipipus hatchlings could walk away from the ground nests as soon as they emerged from their eggs. The asymmetry of egg poles are unique features of Gobipipus eggs (oogenus Gobioolithus) among Cretaceous avialans. The microstructure of the shell in Gobioolithus eggs with the embryos of Gobipipus is typical avian (of ornithoid basic type) and less ratite-like in morphology of the spongy layer than is that in the other possible egg-remains of enantiornitine birds (oofamily Laevisoolithidae). 相似文献
9.
Lyudmila A. Romanenko Naoto Tanaka Natalia I. Kalinovskaya Valery V. Mikhailov 《World journal of microbiology & biotechnology》2013,29(7):1169-1177
The aim of this study was to survey microorganisms from the deep surface sediment samples collected from the Sea of Japan and to screen them for antimicrobial and antagonistic effects. Phylogenetic analysis revealed most isolates sharing 98–100 % sequence similarity to recognized species, including those recovered previously from marine or saline environments. Alteromonas, Halomonas, Marinobacter, Pseudoalteromonas, Salinicola, within the class Gammaproteobacteria, Sulfitobacter (Alphaproteobacteria), Bacillus, Paenibacillus and Paenisporosarcina (Firmicutes), Nocardiopsis and Streptomyces (Actinobacteria) occurred abundantly in all sediment samples. Antimicrobial screening revealed twenty three strains (13 %) capable to inhibit growth of one to eight test cultures and deep sediment isolates. Based on phylogenetic analysis mostly active strains belonged to the genera Bacillus, Brevibacillus, Nocardiopsis, Paenibacillus and Streptomyces. Antimicrobial substances (1–3) were isolated from strain Paenibacillus sp. Sl 79w showing a high inhibitory activity. On the basis of combined spectral analyses (IR, UV, 1H and 13C NMR) the compounds 1, 2 and 3 with [M + H]+ at 409.1 and 409.2 m/z, and with [M + Na]+ at 822.5 m/z were found to have a carbon skeleton of isocoumarin and peptide antibiotics, respectively. Our findings demonstrated that the deep surface sediments of the Sea of Japan represent an untapped source of diverse microorganisms capable of antimicrobial metabolite production. 相似文献
10.
M. V. Stanovova P. A. Erokhov N. G. Gornostaev V. S. Mikhailov Yu. V. Lyupina 《Doklady. Biochemistry and biophysics》2016,471(1):428-430
We investigated functioning of proteasomes and chaperones in Arenicola marina coelomocytes in conditions of lipopolysaccharide-induced inflammation. We observed the increase of chymotrypsin-like proteasome activity in coelomocytes 1 h after induction. Amount of proteasome subunits alpha- and beta-5 types increased as well. We also detected appearance of a new form of Hsp70 chaperone in infected coelomocytes. Our results allow us to consider the changes in proteasome structure and induction of chaperones as principle mechanisms in stress adaptation and defensive reactions development in annelids. 相似文献