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排序方式: 共有153条查询结果,搜索用时 15 毫秒
21.
Francine P. Favaro Lucas Alvizi Roseli M. Zechi-Ceide Debora Bertola Temis M. Felix Josiane de Souza Salmo Raskin Stephen R.F. Twigg Andrea M.J. Weiner Pablo Armas Ezequiel Margarit Nora B. Calcaterra Gregers R. Andersen Simon J. McGowan Andrew O.M. Wilkie Antonio Richieri-Costa Maria L.G. de Almeida Maria Rita Passos-Bueno 《American journal of human genetics》2014
22.
Background
Microarray experiments, as well as other genomic analyses, often result in large gene sets containing up to several hundred genes. The biological significance of such sets of genes is, usually, not readily apparent. 相似文献23.
24.
JR Sara SM Marr WJ Smit LJC Erasmus WJ Luus-Powell 《African Journal of Aquatic Science》2017,42(3):287-291
Muscle tissue from 63 Synodontis zambezensis collected bimonthly in 2013 at Flag Boshielo Dam were analysed for metals and metalloids in a desktop human health risk assessment. The Hazard Quotient, based on a weekly meal of 67 g of fish muscle, exceeded the maximum acceptable level of one for lead, cobalt, cadmium, mercury, arsenic and selenium. The concentrations of these elements were higher in 2013 than those recorded in 2009 and 2012 in other fish species from Flag Boshielo Dam and these may pose a long-term health risk if consumed regularly by impoverished rural communities reliant on fish as a source of protein. 相似文献
25.
Homogenization of geographical variants at the nontranscribed spacer of rDNA in Drosophila mercatorum 总被引:2,自引:0,他引:2
rDNA nontranscribed spacer (NTS) lengths of Drosophila mercatorum have been
measured in individuals from several geographic regions. Individuals from
the different geographic subpopulations share some length fragments but are
in general distinct. The length differences, both within and between
individuals, arise from different copy numbers of a 250-bp repeating unit
that is localized to one part of the NTS. In addition to the length
differences caused by the 250-bp repeat, there is a Y chromosome
(male)-specific length variant elsewhere in the NTS that is approximately
70 bp shorter than the NTS fragment from the X chromosome. Sexual
dimorphism seems to be present in all Drosophila. Also, D. mercatorum has
fewer NTS length variants per individual than does D. melanogaster while
possessing comparable levels of restriction- site polymorphism. The
mechanisms that may cause this pattern of variation are selection, gene
conversion, and unequal recombination.
相似文献
26.
The influence of optimization target selection on the structure of arterial tree models generated by constrained constructive optimization 总被引:1,自引:1,他引:0
W Schreiner F Neumann M Neumann A End SM Roedler S Aharinejad 《The Journal of general physiology》1995,106(4):583-599
The computational method of constrained constructive optimization was used to generate complex arterial model trees by optimization with respect to a target function. Changing the target function also changes the tree structure obtained. For a parameterized family of target functions a series of trees was created, showing visually striking differences in structure that can also be quantified by appropriately chosen numerical indexes. Blood transport path length, pressure profile, and an index for relative segment orientation show clear dependencies on the optimization target, and the nature of changes can be explained on theoretical grounds. The main goal was to display, quantify, and explain the structural changes induced by different optimization target functions. 相似文献
27.
Naphthalene dioxygenase (NDO) fromPseudomonas sp strain NCIB 9816 is a multicomponent enzyme system which initiates naphthalene catabolism by catalyzing the addition of both atoms of molecular oxygen and two hydrogen atoms to the substrate to yield enantiomerically pure (+)-cis-(1R,2S)-dihydroxy-1,2-dihydronaphthalene. NDO has a relaxed substrate specificity and catalyzes the dioxygenation of many related 2- and 3-ring aromatic and hydroaromatic (benzocyclic) compounds to their respectivecis-diols. Biotransformations with a diol-accumulating mutant, recombinant strains and purified enzyme components have established that in addition tocis-dihydroxylation, NDO also catalyzes a variety of other oxidations which include monohydroxylation, desaturation (dehydrogenation),O-andN-dealkylation and sulfoxidation reactions. In several cases, the absolute stereochemistry of the oxidation products formed by NDO are opposite to those formed by toluene dioxygenase (TDO). The reactions catalyzed by NDO and other microbial dioxygenases can yield specific hydroxylated compounds which can serve as chiral synthons in the preparation of a variety of compounds of interest to pharmaceutical and specialty chemical industries. We present here recent work documenting the diverse array of oxidation reactions catalyzed by NDO. The trends observed in the oxidation of a series of benzocyclic aromatic compounds are compared to those observed with TDO and provide the basis for prediction of regio- and stereospecificity in the oxidation of related substrates. Based on the types of reactions catalyzed and the biochemical characteristics of NDO, a mechanism for oxygen activation by NDO is proposed. 相似文献
28.
29.
Sequence of a cDNA for mouse thymidylate synthase reveals striking similarity with the prokaryotic enzyme 总被引:11,自引:0,他引:11
Perryman SM; Rossana C; Deng TL; Vanin EF; Johnson LF 《Molecular biology and evolution》1986,3(4):313-321
We report the nucleotide sequence of a cloned cDNA, pMTS-3, that contains a
1-kb insert corresponding to mouse thymidylate synthase (E.C. 2.1.1.45).
The open reading frame of 921 nucleotides from the first AUG to the
termination codon specifies a protein with a molecular mass of 34,962
daltons. The predicted amino acid sequence is 90% identical with that of
the human enzyme. The mouse sequence also has an extremely high degree of
similarity (as much as 55% identity) with prokaryotic thymidylate synthase
sequences, indicating that thymidylate synthase is among the most highly
conserved proteins studied to date. The similarity is especially pronounced
(as much as 80% identity) in the 44-amino-acid region encompassing the
binding site for deoxyuridylic acid. The cDNA sequence also suggests that
mouse thymidylate synthase mRNA lacks a 3' untranslated region, since the
termination codon, UAA, is followed immediately by a poly(A) segment.
相似文献
30.