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31.
Vijay K. Mahajan Dominic M. Desiderio 《Biochemical and biophysical research communications》1978,82(4):1104-1110
The amino acid sequence of oligopeptides can be determined from the mass spectra of their volatile derivatives. New peptide derivatives are described which are prepared from permethylated peptides by reduction with borane-tetrahydrofuran. These derivatives have been found to be more volatile than the corresponding permethylated ones. The procedure is illustrated by application of this technique to representative oligopeptides. As little as 10–100 nmol of these peptides have been sequenced using this technique. 相似文献
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Many types of invisible electromagnetic waves are produced in our atmosphere. When these radiations penetrate our body, electric fields are induced inside the body, resulting in the absorption of power, which is different for different body parts and also depends on the frequency of radiations. Higher power absorption may result into health problems. In this communication, effects of electromagnetic waves (EMW) of 41 and 202 MHz frequencies transmitted by the TV tower have been studied on skin, muscles, bone and fat of human. Using international standards for safe exposure limits of specific absorption rate (SAR), we have found the safe distance from TV transmission towers for two frequencies. It is suggested that transmission towers should be located away from the thickly populated areas and people should keep away from the transmission towers, as they radiate electromagnetic radiations that are harmful to some parts/tissues of body. 相似文献
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37.
Surendra K. Gond Ashish Mishra Vijay K. Sharma Satish K. Verma Jitendra Kumar Ravindra N. Kharwar Anuj Kumar 《Mycoscience》2012,53(2):113-121
Endophytic fungi from Nyctanthes arbor-tristis were isolated and evaluated for their antimicrobial activity. A total of 19 endophytic fungi were isolated from 400 segments
of healthy leaf and stem tissues of N. arbor-tristis. Eighteen endophytic fungi were obtained from leaf, while only ten from stem. Alternaria alternata had the highest colonization frequency (15.0%) in leaf, whereas Cladosporium cladosporioides ranked first in stem with a colonization frequency of 12%. The diversity and species richness were found higher in leaf tissues
than in stem. The similarity indices between leaf and stem were 0.473 for Jaccard’s and 0.642 for the Sorenson index, respectively.
Of 16, 12 (75%) endophytic fungal extracts showed antibacterial activity against either one or more pathogenic bacteria. The
endophytic Nigrospora oryzae showed maximum inhibition against Shigella sp. and Pseudomonas aeruginosa. The leaf endophytes Colletotrichum dematium and Chaetomium globosum exhibited a broad range of anibacterial activity and were active against Shigella flexnii, Shigella boydii, Salmonella enteritidis, Salmonella paratyphi, and P. aeruginosa. Nine out of 16 (56.25%) endophytic fungi exhibited antifungal activity to one or more fungal pathogens. Colletotrichum dematium inhibited 55.87% of the radial growth of the phytopathogen Curvularia lunata. The antimicrobial activity of these endophytic microorganisms could be exploited in the biotechnological, medicinal, and
agricultural industries. 相似文献
38.
Wouter L. W. Hazenbos Kimberly K. Kajihara Richard Vandlen J. Hiroshi Morisaki Sophie M. Lehar Mark J. Kwakkenbos Tim Beaumont Arjen Q. Bakker Qui Phung Lee R. Swem Satish Ramakrishnan Janice Kim Min Xu Ishita M. Shah Binh An Diep Tao Sai Andrew Sebrell Yana Khalfin Angela Oh Chris Koth S. Jack Lin Byoung-Chul Lee Magnus Strandh Klaus Koefoed Peter S. Andersen Hergen Spits Eric J. Brown Man-Wah Tan Sanjeev Mariathasan 《PLoS pathogens》2013,9(10)
Infection of host tissues by Staphylococcus aureus and S. epidermidis requires an unusual family of staphylococcal adhesive proteins that contain long stretches of serine-aspartate dipeptide-repeats (SDR). The prototype member of this family is clumping factor A (ClfA), a key virulence factor that mediates adhesion to host tissues by binding to extracellular matrix proteins such as fibrinogen. However, the biological siginificance of the SDR-domain and its implication for pathogenesis remain poorly understood. Here, we identified two novel bacterial glycosyltransferases, SdgA and SdgB, which modify all SDR-proteins in these two bacterial species. Genetic and biochemical data demonstrated that these two glycosyltransferases directly bind and covalently link N-acetylglucosamine (GlcNAc) moieties to the SDR-domain in a step-wise manner, with SdgB appending the sugar residues proximal to the target Ser-Asp repeats, followed by additional modification by SdgA. GlcNAc-modification of SDR-proteins by SdgB creates an immunodominant epitope for highly opsonic human antibodies, which represent up to 1% of total human IgG. Deletion of these glycosyltransferases renders SDR-proteins vulnerable to proteolysis by human neutrophil-derived cathepsin G. Thus, SdgA and SdgB glycosylate staphylococcal SDR-proteins, which protects them against host proteolytic activity, and yet generates major eptopes for the human anti-staphylococcal antibody response, which may represent an ongoing competition between host and pathogen. 相似文献
39.
Vijay M. Khedkar Premlata K. Ambre Jitender Verma Mushtaque S. Shaikh Raghuvir R. S. Pissurlenkar Evans C. Coutinho 《Journal of molecular modeling》2010,16(7):1251-1268
HIV-1 protease is an obligatory enzyme in the replication process of the HIV virus. The abundance of structural information
on HIV-1PR has made the enzyme an attractive target for computer-aided drug design strategies. The daunting ability of the
virus to rapidly generate resistant mutants suggests that there is an ongoing need for new HIV-1PR inhibitors with better
efficacy profiles and reduced toxicity. In the present investigation, molecular modeling studies were performed on a series
of 54 cyclic urea analogs with symmetric P2/P2′ substituents. The binding modes of these inhibitors were determined by docking.
The docking results also provided a reliable conformational superimposition scheme for the 3D-QSAR studies. To gain insight
into the steric, electrostatic, hydrophobic and hydrogen-bonding properties of these molecules and their influence on the
inhibitory activity, comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA)
were performed. Two different alignment schemes viz. receptor-based and atom-fit alignment, were used in this study to build the QSAR models. The derived 3D-QSAR models were found to be robust with statistically
significant r
2
and r
2
pred
values and have led to the identification of regions important for steric, hydrophobic and electronic interactions. The predictive
ability of the models was assessed on a set of molecules that were not included in the training set. Superimposition of the
3D-contour maps generated from these models onto the active site of enzyme provided additional insight into the structural
requirements of these inhibitors. The CoMFA and CoMSIA models were used to design some new inhibitors with improved binding
affinity. Pharmacokinetic and toxicity predictions were also carried out for these molecules to gauge their ADME and safety
profile. The computational results may open up new avenues for synthesis of potent HIV-1 protease inhibitors. 相似文献
40.
Beena E. Thomas Puneet K. Dewan Sophia Vijay Aleyamma Thomas Lakhdir Singh Chauhan Chandrasekaran Vedachalam Preetish Vaidyanathan Soumya Swaminathan 《PloS one》2009,4(12)