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151.
Jeyasekaran G. Raj K. Thirumalai Shakila R. Jeya Thangarani A. Jemila Sukumar D. Jailani V. Abdul Kadhar 《World journal of microbiology & biotechnology》2011,27(4):953-959
A multiplex PCR based assay was developed for the identification of the genus Salmonella. Five sets of primers from different genomic sequences such as fimA, himA,
hns, invA and hto genes were selected for the identification of serogroups of Salmonella
enterica such as S. Typhi, S. ParatyphiA, S. Typhimurium, S. Enteritidis and S. Weltevreden. The selected primers amplified products with the sizes of 85, 123, 152, 275 and 496 bp, respectively, for the
genus Salmonella. This assay was found to be highly sensitive, as it could detect 5 cells of Salmonella and 1,000 fg of genomic DNA. Amplification of DNA extracted from other genera viz. V. cholerae and E. coli yielded negative results. This assay provides specific and reliable results and allows for the cost–effective detection of
Salmonella in one reaction tube in mixed bacterial communities. 相似文献
152.
Singh P Sachdeva S Raj R Kumar V Mahajan MP Nasser S Vivas L Gut J Rosenthal PJ Feng TS Chibale K 《Bioorganic & medicinal chemistry letters》2011,21(15):4561-4563
3-Azido-, 3-amino- and 3-(1,2,3-triazol-1-yl)-β-lactams were synthesized and evaluated for their antiplasmodial activity against four strains of Plasmodium falciparum and KB cells for their cytotoxicity profiles. The presence of a cyclohexyl substituent at N-1 and a phenyl group on the triazole ring markedly improved the activity profiles of triazole-tethered β-lactam exhibiting IC50 values of 1.13, 1.21 and 1.00 μM against 3D7, K1 and W2 strains respectively. 相似文献
153.
Nepali K Agarwal A Sapra S Mittal V Kumar R Banerjee UC Gupta MK Satti NK Suri OP Dhar KL 《Bioorganic & medicinal chemistry》2011,19(18):5569-5576
A series of forty two N-(1,3-diaryl-3-oxopropyl)amides were synthesized via an efficient, modified Dakin-West reaction and were evaluated for in vitro xanthine oxidase inhibitory activity for the first time. Structure-activity relationship analyses have been presented. Selected active xanthine oxidase inhibitors (3r, 3s, and 3zh) were assessed in vivo to study their anti-hyperuricemic effect in potassium oxonate induced hyperuricemic mice model. Compound 3s emerged as the most potent xanthine oxidase inhibitor (IC(50)=2.45 μM) as well as the most potent anti-hyperuricemic agent. The basis of significant inhibition of xanthine oxidase by 3s was rationalized by its molecular docking into catalytic site of xanthine oxidase. 相似文献
154.
This study aimed to design novel nitrogen-rich heptazine derivatives as high energy density materials (HEDM) by exploiting
systematic structure–property relationships. Molecular structures with diverse energetic substituents at varying positions
in the basic heptazine ring were designed. Density functional techniques were used for prediction of gas phase heat of formation
by employing an isodesmic approach, while crystal density was assessed by packing calculations. The results reveal that nitro
derivatives of heptazine possess a high heat of formation and further enhancement was achieved by the substitution of nitro
heterocycles. The crystal packing density of the designed compounds varied from 1.8 to 2 g cm−3, and hence, of all the designed molecules, nitro derivatives of heptazine exhibit better energetic performance characteristics
in terms of detonation velocity and pressure. The calculated band gap of the designed molecules was analyzed to establish
sensitivity correlations, and the results reveal that, in general, amino derivatives possess better insensitivity characteristics.
The overall performance of the designed compounds was moderate, and such compounds may find potential applications in gas
generators and smoke-free pyrotechnic fuels as they are rich in nitrogen content. 相似文献
155.
Savidge TC Urvil P Oezguen N Ali K Choudhury A Acharya V Pinchuk I Torres AG English RD Wiktorowicz JE Loeffelholz M Kumar R Shi L Nie W Braun W Herman B Hausladen A Feng H Stamler JS Pothoulakis C 《Nature medicine》2011,17(9):1136-1141
The global prevalence of severe Clostridium difficile infection highlights the profound clinical significance of clostridial glucosylating toxins. Virulence is dependent on the autoactivation of a toxin cysteine protease, which is promoted by the allosteric cofactor inositol hexakisphosphate (InsP(6)). Host mechanisms that protect against such exotoxins are poorly understood. It is increasingly appreciated that the pleiotropic functions attributed to nitric oxide (NO), including host immunity, are in large part mediated by S-nitrosylation of proteins. Here we show that C. difficile toxins are S-nitrosylated by the infected host and that S-nitrosylation attenuates virulence by inhibiting toxin self-cleavage and cell entry. Notably, InsP(6)- and inositol pyrophosphate (InsP(7))-induced conformational changes in the toxin enabled host S-nitrosothiols to transnitrosylate the toxin catalytic cysteine, which forms part of a structurally conserved nitrosylation motif. Moreover, treatment with exogenous InsP(6) enhanced the therapeutic actions of oral S-nitrosothiols in mouse models of C. difficile infection. Allostery in bacterial proteins has thus been successfully exploited in the evolutionary development of nitrosothiol-based innate immunity and may provide an avenue to new therapeutic approaches. 相似文献
156.
Dihydrouridine (DHU) positions within tRNAs have long been used as sites to covalently attach fluorophores, by virtue of their unique chemical reactivity toward reduction by NaBH(4), their abundance within prokaryotic and eukaryotic tRNAs, and the biochemical functionality of the labeled tRNAs so produced. Interpretation of experiments employing labeled tRNAs can depend on knowing the distribution of dye among the DHU positions present in a labeled tRNA. Here we combine matrix-assisted laser desorption/ionization mass spectroscopy (MALDI-MS) analysis of oligonucleotide fragments and thin layer chromatography to resolve and quantify sites of DHU labeling by the fluorophores Cy3, Cy5, and proflavin in Escherichia coli tRNA(Phe) and E. coli tRNA(Arg). The MALDI-MS results led us to re-examine the precise chemistry of the reactions that result in fluorophore introduction into tRNA. We demonstrate that, in contrast to an earlier suggestion that has long been unchallenged in the literature, such introduction proceeds via a substitution reaction on tetrahydrouridine, the product of NaBH(4) reduction of DHU, resulting in formation of substituted tetrahydrocytidines within tRNA. 相似文献
157.
Ledesma MC Jung-Hynes B Schmit TL Kumar R Mukhtar H Ahmad N 《Molecular medicine (Cambridge, Mass.)》2011,17(1-2):134-143
Various formulations of selenium and vitamin E, both essential human dietary components, have been shown to possess a therapeutic and preventive effect against prostate cancer. Fortuitous results of clinical trials also implied a risk-reduction effect of selenium and vitamin E supplements. The Selenium and Vitamin E Cancer Prevention Trial (SELECT), using oral selenium and vitamin E supplementation in disease-free volunteers, was designed to test a prostate cancer chemoprevention hypothesis. SELECT was terminated early because of both safety concerns and negative data for the formulations and doses given. Here, we review and discuss the studies done before and since the inception of SELECT, as well as the parameters of the trial itself. We believe that there is a lack of appropriate in vivo preclinical studies on selenium and vitamin E despite many promising in vitro studies on these agents. It seems that the most effective doses and formulations of these agents for prostate cancer chemoprevention have yet to be tested. Also, improved understanding of selenium and vitamin E biology may facilitate the discovery of these doses and formulations. 相似文献
158.
159.
Arginine is one of the commonly used additives to enhance refolding yield of proteins, to suppress aggregation of proteins, and to increase solubility of proteins, and yet the molecular interactions that contribute to the role of arginine are unclear. Here, we present experiments, using bovine serum albumin (BSA), lysozyme (LYZ), and β-lactoglobulin (BLG) as model proteins, to show that arginine can enhance heat-induced aggregation of concentrated protein solutions, contrary to the conventional belief that arginine is a universal suppressor of aggregation. Results show that the enhancement in aggregation is caused only for BSA and BLG, but not for LYZ, indicating that arginine's preferential interactions with certain residues over others could determine the effect of the additive on aggregation. We use this previously unrecognized behavior of arginine, in combination with density functional theory calculations, to identify the molecular-level interactions of arginine with various residues that determine arginine's role as an enhancer or suppressor of aggregation of proteins. The experimental and computational results suggest that the guanidinium group of arginine promotes aggregation through the hydrogen-bond-based bridging interactions with the acidic residues of a protein, whereas the binding of the guanidinium group to aromatic residues (aggregation-prone) contributes to the stability and solubilization of the proteins. The approach, we describe here, can be used to select suitable additives to stabilize a protein solution at high concentrations based on an analysis of the amino acid content of the protein. 相似文献
160.
Thachamvally Riyesh Vinayagamurthy Balamurugan Arnab Sen Veerakyathappa Bhanuprakash Gnanavel Venkatesan Vinita Yadav Raj Kumar Singh 《中国病毒学》2011,26(5):324-337
In this study, thermo-adapted (Ta) PPR vaccines were assessed for their stability at 25, 37, 40, 42 and 45°C in lyophilized
form using two extrinsic stabilizers {lactalbumin hydrolysate-sucrose (LS) and stabilizer E} and in reconstituted form with
the diluents (1 mol/L MgSO4 or 0.85% NaCl). The lyophilized vaccines showed an expiry period of 24–26 days at 25°C, 7–8 days at 37°C and 3–4 days at
40°C. LS stabilizer was superior at 42°C with a shelf-life of 44 h, whereas in stabilizer E, a 40 h shelf-life with a comparable
half-life was observed. At 45°C, the half-life in stabilizer E was better than LS and lasted for 1 day. Furthermore, the reconstituted
vaccine maintained the titre for 48 h both at 4°C and 25°C and for 24–30 h at 37°C. As both the stabilizers performed equally
well with regard to shelf-life and half-life, the present study suggests LS as stabilizer as a choice for lyophilization with
0.85% NaCl diluent, because it has better performance at higher temperature. These Ta vaccines can be used as alternatives
to existing vaccines for the control of the disease in tropical countries as they are effective in avoiding vaccination failure
due to the breakdown in cold-chain maintenance, as this vaccine is considerably more stable at ambient temperatures. 相似文献