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1.
Egon Amann  Jürgen Brosius   《Gene》1985,40(2-3):183-190
A plasmid cloning vector system has been constructed that allows for the production of large quantities of foreign proteins or fragments thereof, in an unfused state. These vectors provide strong regulated trp-lac fusion promoters and the lacZ ribosome-binding site (RBS) followed by an ATG translation initiation codon at an appropriate distance from the RBS. The ATG codon is located within a unique NcoI restriction site (CCATGG). Digestion with NcoI exposes the ATG for fusion. Gene fragments lacking a prokaryotic RBS and/or ATG start codons can be inserted in several ways. Expression experiments using a truncated cI gene of bacteriophage A or a large portion of the coding region of the Herpes simplex virus type l glycoprotein D gene have been performed. The results of these studies show that the vectors are useful for the high-level expression of prokaryotic and eukaryotic genes in Escherichia coli.  相似文献
2.
Gene expression and molecular evolution   总被引:32,自引:0,他引:32  
The combination of complete genome sequence information and estimates of mRNA abundances have begun to reveal causes of both silent and protein sequence evolution. Translational selection appears to explain patterns of synonymous codon usage in many prokaryotes as well as a number of eukaryotic model organisms (with the notable exception of vertebrates). Relationships between gene length and codon usage bias, however, remain unexplained. Intriguing correlations between expression patterns and protein divergence suggest some general mechanisms underlying protein evolution.  相似文献
3.
The plant translational apparatus   总被引:22,自引:0,他引:22  
Protein synthesis in both eukaryotic and prokaryotic cells is a complex process requiring a large number of macromolecules: initiation factors, elongation factors, termination factors, ribosomes, mRNA, amino-acylsynthetases and tRNAs. This review focuses on our current knowledge of protein synthesis in higher plants.Abbreviations eIF eukaryotic initiation factor - eEF eukaryotic elongation factor - EST expressed sequence tag - eRF eukaryotic release factor - GUS -glucoronidase - HCR heme-controlled repressor - PKR double-stranded - RNA activated protein kinase - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis  相似文献
4.
Pep5, a new lantibiotic: structural gene isolation and prepeptide sequence   总被引:21,自引:0,他引:21  
A wobbled 14-mer oligonucleotide was derived from the amino acid sequence of the 34-residue propeptide of the lantibiotic Pep5 (Kellner et al. 1989). Using this hybridization probe, the structural gene of Pep5, pepA, was located on the 18.6 kbp plasmid pED503. The nucleotide sequence of pepA codes for a prepeptide with 60 residues and proves that Pep5 is ribosomally synthesized. The N-terminus of the prepeptide has a high -helix probability and a characteristic proteolytic cleavage site precedes the C-terminal 34-residue propeptide. Our present theory is that maturation of Pep5 involves (a) enzymic conversion of Thr, Ser and Cys into dehydrated amino acids and sulfide bridges, (b) membrane translocation and cleavage of the modified prepeptide.Dedicated to Prof. H. Zähner on the occasion of his sixtieth birthday  相似文献
5.
水稻线粒体基因组翻译产物与细胞质雄性不育性   总被引:21,自引:4,他引:17  
通过线粒体离体翻译产物的电泳和放射性自显影分析,发现水稻BT型不育细胞质(农虎26A和丰锦A不育系)的线粒体基因产物比可育细胞质(农虎26B和丰锦B保持系)缺少一个22KD多肽。它反应了BT型不育细胞质线粒体基因组中有关育性的基因变异。不育系与恢复系杂交后,杂种F_1的育性虽然恢复,但是它的线粒体基因产物中仍然缺少22KD多肽。然而,在杂种F_1的线粒体蛋白质的电泳染色图谱中则显示出一个22KD多肽条带。杂种F_1中的这个22KD多肽是核基因产物。它弥补了线粒体基因组中育性基因的缺陷。  相似文献
6.
A single determinant dominates the rate of yeast protein evolution   总被引:21,自引:0,他引:21  
A gene's rate of sequence evolution is among the most fundamental evolutionary quantities in common use, but what determines evolutionary rates has remained unclear. Here, we carry out the first combined analysis of seven predictors (gene expression level, dispensability, protein abundance, codon adaptation index, gene length, number of protein-protein interactions, and the gene's centrality in the interaction network) previously reported to have independent influences on protein evolutionary rates. Strikingly, our analysis reveals a single dominant variable linked to the number of translation events which explains 40-fold more variation in evolutionary rate than any other, suggesting that protein evolutionary rate has a single major determinant among the seven predictors. The dominant variable explains nearly half the variation in the rate of synonymous and protein evolution. We show that the two most commonly used methods to disentangle the determinants of evolutionary rate, partial correlation analysis and ordinary multivariate regression, produce misleading or spurious results when applied to noisy biological data. We overcome these difficulties by employing principal component regression, a multivariate regression of evolutionary rate against the principal components of the predictor variables. Our results support the hypothesis that translational selection governs the rate of synonymous and protein sequence evolution in yeast.  相似文献
7.
"植硅体"含义和禾本科植硅体的分类   总被引:20,自引:2,他引:18  
针对国内文献中对英文“Phytolith”等词语的中文译名呈多样化现象,建议统一用“植硅体”来涵盖之,其含义包括“Opal phytolith”和“Silica bodies”等,代表一门新兴学科,即植硅体学,已有的禾本科植硅体分类中,不同学者采用了各自不同的分类规则和术语,本文通过分析,对比现有禾本科植硅体不同的分类方案,以期对其分类系统的研究现状和所存在问题提出看法,有利于今后深入研究。  相似文献
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A new revision of the sequence of plasmid pBR322   总被引:19,自引:0,他引:19  
Ned Watson 《Gene》1988,70(2):399-403
A revised sequence in the region immediately upstream from the rop gene of pBR322 is reported. Two base pairs in the accepted sequence do not exist in the plasmid DNA. Specifically, a TA base pair is missing at sequence coordinate 1893 [Sutcliffe, Cold Spring Harbor Symp. Quant. Biol. 43 (1979) 77–90] and an AT base pair is missing at position 1915, giving a total size for pBR322 of 4361 bp. These changes are in a potential translation initiation sequence and probably reflect errors in the original sequence rather than recent evolution of the plasmid.  相似文献
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