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991.
Err-Cheng Chan C. Allen Chang Tzong-Zeng Wu Yuh-Ling Lin 《Biotechnology letters》1998,20(11):1053-1056
The normal human epidermal keratinocyte (NHEK) was used to evaluate the cytotoxicity of recombinant lysostaphin. As determined with the Neutral Red (NR) cytotoxicity assay, the midpoint toxicity value (NR50) after 48 h exposure was 16 ± 0.4 g lysostaphin/l. Lysostaphin cytotoxicity effect is much less than the surface active agent, sodium laurate. However, the NR50 value after 48-h exposure was 1.9 ± 0.02 g/l for S. aureus lysate derived from the bacterial lytic action of lysostaphin. A linear increase in interleukin-8 (IL-8) level in NHEK cells from resting levels of 65 ± 3 pg/ml to peak of 760 ± 15 pg/ml during the first 9 hours was noted for the cells treated with 800 mg lysostaphin/l. S. aureus lysate has the same effect on the induction of IL-8 levels. The induced rises in IL-8 were lysostaphin and S. aureus lysate concentration dependence. © Rapid Science Ltd. 1998 相似文献
992.
Stanislava Uhrínová Dušan Uhrín Helen Denton Mark Smith Lindsay Sawyer Paul N. Barlow 《Journal of biomolecular NMR》1998,12(1):89-107
Although -lactoglobulin (-LG) has been studied extensively for more than 50 years, its physical properties in solution are not yet understood fully in terms of its three-dimensional (3D) structure. For example, despite a recent high-resolution crystal structure, it is still not clear why the two common variants of bovine -LG which differ by just two residues have different aggregation properties during milk processing. We have conducted solution-state NMR studies on a recombinant form of the A variant of -LG at low pH conditions where the protein is partially unfolded and exists as a monomer rather than a dimer. Using a13 C,15N-labelled sample, expressed in Pichia pastoris, we have employed the standard combination of 3D heteronuclear NMR techniques to obtain near complete assignments of proton, carbon and nitrogen resonances. Using a novel pulse sequence we were able to obtain additional assignments, in particular those of methyl groups in residues preceding proline within the sequence. From chemical shifts and on the basis of inter-residue NOEs, we have inferred the secondary structure and topology of monomeric -LG A. It includes eight antiparallel -strands arranged in a barrel, flanked by an -helix, which is typical of a member of the lipocalin family. A detailed comparison with the crystal structure of the dimeric form (for a mixture of A and B variants) at pH 6.5 reveals a close resemblance in both secondary structure and overall topology. Both forms have a ninth -strand which, at the higher pH, forms part of the dimer interface. These studies represent the first full NMR assignment of -LG and will form the basis for a complete characterisation of the solution structure and dynamics of this protein and its variants. 相似文献
993.
Nellie Y. Loh Helen J. Ambrose Lisa M. Guay-Woodford Srimita DasGupta Ralph A. Nawrotzki Derek J. Blake Kay E. Davies 《Mammalian genome》1998,9(11):857-862
β-Dystrobrevin, a dystrophin-related protein that is expressed in non-muscle tissues, is highly homologous to α-dystrobrevin,
a member of the dystrophin-associated protein complex (DPC). β-Dystrobrevin associates with Dp71 and syntrophin and is believed
to have a role in non-muscle DPCs. Here we report the characterization and mapping of the mouse β-dystrobrevin gene. The mouse
β-dystrobrevin gene is organized into 21 exons spanning over 130 kb of DNA. We provide evidence that this gene is transcribed
from at least two promoter regions but appears to utilize a common translation initiation site. We show that the similarity
between β-dystrobrevin and α-dystrobrevin is reflected in the conservation of their exon-intron junctions. β-Dystrobrevin
has been localized to proximal mouse Chromosome (Chr) 12 by backcross mapping. A database search revealed that two mouse genetic
diseases involving tissues expressing β-dystrobrevin have been mapped to this region, namely, congenital polycystic kidneys
(cpk) and fatty liver dystrophy (fld). However, refined mapping analysis has excluded β-dystrobrevin as a candidate gene for either disease.
Received: 1 June 1998 / Accepted: 16 July 1998 相似文献
994.
José Manuel Fernández-Ábalos Helen Fox Chris Pitt Brian Wells & John H. Doonan 《Molecular microbiology》1998,27(1):121-130
Green fluorescent protein (GFP) is a useful reporter to follow the in vivo behaviour of proteins, but the wild-type gfp gene does not function in many organisms, including many plants and filamentous fungi. We show that codon-modified forms of gfp , produced for use in plants, function effectively in Aspergillus nidulans both as gene expression reporters and as vital reporters for protein location. To demonstrate the use of these modified gfp s as reporter genes we have used fluorescence to follow ethanol-induced GFP expression from the alcA promoter. Translational fusions with the modified gfp were used to follow protein location in living cells; plant ER-retention signals targeted GFP to the endoplasmic reticulum, whereas fusion to the GAL4 DNA-binding domain targeted it to the nucleus. Nuclear-targeted GFP allowed real-time observation of nuclear movement and division. These modified gfp genes should provide useful markers to follow gene expression, organelle behaviour and protein trafficking in real time. 相似文献
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998.
Paul Nguyen-Ba Nola Lee Helen Mitchell Laval Chan Miguel Quimpère 《Bioorganic & medicinal chemistry letters》1998,8(24):3675-3560
A novel class of cyclic nucleotide analogs has shown anti-HCMV activity. The synthesis as well as structure - activity relationship studies are presented. 相似文献
999.
黑曲霉T21是由黑曲霉3.795经诱变育种获得的糖化酶高产菌株,为阐明其高产的分子机制,由黑曲霉3.795克隆了糖化酶结构基因及其5′旁侧序列,并与黑曲霉T21的相应序列进行了比较.由黑曲霉3.795菌丝体分离染色体DNA,Southern杂交分析表明,糖化酶结构基因位于~2.5kb的EcoRⅠ-EcoRⅤ染色体DNA片段上,在此EcoRⅠ位点上游约1.0kb处有一SalⅠ位点.为构建糖化酶结构基因及其5′旁侧序列的基因组文库,该染色体DNA分别用EcoRⅠ+EcoRⅤ和EcoR+SalⅠ消化,琼脂糖凝胶电泳分离并回收长度在1.0kb左右和2.5kb左右的DNA片段,分别与pUC19载体连接后转化入E.coliDH5.用原位杂交方法筛选到了携带糖化酶基因编码区及其1505bp5′旁侧序列的阳性克隆.对克隆片段的DNA序列进行了测定并与黑曲霉T21的相应序列进行了比较,结果表明,在糖化酶基因编码区及其150bp3′非编码区内,未发现碱基差异,但在-340~-1505的5′上游区内发生了9个位置的碱基变化,包括缺失、插入和替换.这些结果表明,黑曲霉T21与3.795的糖化酶产量的差异与其结构基因无关,但可能与其 相似文献
1000.