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1.
Paclobutrazol, triapenthenol (RSW0411), and BAS111 were applied to 4-week-old Delicious apple seedlings (Malus domestica Borkh.) as a root drench at 0.1, 1.0, and 10.0 mg per plant. Paclobutrazol eliminated shoot extension growth for 8 weeks
at all three rates. RSW0411 controlled shoot elongation only at the highest rate. BAS111 produced the widest response, with
shoot growth ranging from 38% to 93% of controls for the highest and lowest rates, respectively. Generally, leaf area decreased
and leaf density increased with increasing rates of all chemicals. Root weight of plants treated with paclobutrazol nearly
doubled but increased only slightly with RSW0411 and BAS111. Chemical analysis of the leaf tissue 8 weeks after treatment
showed paclobutrazol levels highest, followed by RSW0411 and BAS111.
Mention of a trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by the U.S.
Department of Agriculture and does not imply its approval to the exclusion of other products that may also be suitable. 相似文献
2.
A method has been developed to assay collagenase in ovarian extracts in the presence of tissue inhibitors. Rat ovarian tissue is first extracted with Triton X-100 and then heated to 60 degrees C in 50 mM Tris buffer containing 100 mM CaCl2. This extract contains collagenase activity and putative inhibitor(s). The inhibitory activity is removed by reduction with dithiothreitol and alkylation with iodoacetamide. Collagenase is then activated with aminophenylmercuric acetate and assayed using 3H-acetylated collagen from which the telopeptides have been removed. Identification of this activity as collagenase was performed by using the metalloprotease inhibitors EDTA and o-phenanthroline and by demonstration of the typical collagen cleavage fragments on sodium dodecyl sulfate-gel electrophoresis. To investigate the changes in collagenase activity associated with ovulation, immature rats received 20 IU of pregnant mare's serum gonadotropin and 52 h later 10 IU of human chorionic gonadotropin (hCG). After hCG administration, ovaries were removed at intervals from 0 to 20 h. Collagenase activity rose from 4.9 +/- 1.4% digestion of the 3H-collagen at 0 time to a maximum of 24.7 +/- 1.5% digestion at 8 h after hCG and remained high at 12 h (time of ovulation) and up to 20 h (18.7 +/- 1.9% and 16.1 +/- 1.6% digestion, respectively). These findings support a role of collagenase in the rupture of the follicle and they suggest a further role for this enzyme in the events following ovulation. 相似文献
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Mapping the polarity profiles of general anesthetic target sites using n-alkane-(alpha, omega)-diols 总被引:1,自引:0,他引:1
The effects of the homologous series of n-alkane-(alpha, omega)-diols have been studied on the inhibition of the purified firefly luciferase enzyme from Photinus pyralis, the inhibition of the purified bacterial luciferase enzyme from Vibrio harveyi, and the induction of general anesthesia in Xenopus laevis tadpoles. All but one of the diols tested were found to be reversible general anesthetics. The diols inhibited firefly luciferase by competing with its normal substrate firefly luciferin, and they inhibited bacterial luciferase by competing with the substrate n-decanal. For all but the smallest agent (1,4-butanediol), only a single diol molecule was found to be involved in the inhibition of the enzymes. Inhibition constants Ki were determined for the enzymes, and general anesthetic EC50 concentrations were determined for tadpoles. These data were then used in conjunction with previously determined n-alkane and n-alcohol data to calculate, as a function of chain length, the incremental standard Gibbs free energies delta (delta G0) for adding apolar -CH2- groups and for converting apolar terminal -CH3 groups to polar -CH2OH groups. The resulting plots of delta (delta G0) versus chain length gave a consistent mapping of the polarity profiles of the anesthetic-binding pockets. They clearly reveal the existence of two substantial and distinct polar regions in the anesthetic-binding pocket of firefly luciferase but only one such region for bacterial luciferase and for the unknown target sites underlying general anesthesia. The polarities and geometric properties of these different binding sites for straight-chain anesthetics are discussed in terms of simple models. 相似文献
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A successful method for the purification of NADP isocitrate dehydrogenase from a plant source, Zea mays, is reported. Two mitochondrial isoenzymes were found and purified to homogeneity by a course of acetone fractionation, bulk exchange on DEAE-cellulose, cellulose hydroxylapatite column chromatography, and continuous elution electrophoresis. The mitochondrial isoenzymes are very similar with respect to kinetic properties, response to solvent perturbation, and temperature dependence of the pH/V relationship of isocitrate dehydrogenation. The Michaelis constant for isocitrate is identical for both isoenzymes. The enzymes have a molecular weight of 81,000 as estimated by permeation chromatography and an isoelectric point of 5.5 as extrapolated from gel-electrophoretic mobilities. Detectable differences are confined to differences in electrophoretic mobilities and heat denaturation. In D2O the rate of the overall reaction from isocitrate to α-ketoglutarate and CO2 was about 3.6 times slower than the same reaction in H2O. Both the forward and reverse reactions, in which isocitrate is dehydrogenated or generated from oxalosuccinate, were observed to decrease by this amount in D2O. The decarboxylation of oxalosuccinate was found to decrease by only about 25% in D2O relative to the velocity of the reaction in H2O. Thus the slow step in the overall reaction must be the initial dehydrogenation step rather than the decarboxylation of oxalosuccinate. The pK of the overall reaction did not change in D2O as compared to H2O. 相似文献
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Eric Hastie Dahlia M. Besmer Nirav R. Shah Andrea M. Murphy Megan Moerdyk-Schauwecker Carlos Molestina Lopamudra Das Roy Jennifer M. Curry Pinku Mukherjee Valery Z. Grdzelishvili 《Journal of virology》2013,87(18):10283-10294
Vesicular stomatitis virus (VSV) is a promising oncolytic agent against various malignancies. Here, for the first time, we tested VSV in vitro and in vivo in a clinically relevant, immunocompetent mouse model of pancreatic ductal adenocarcinoma (PDA). Our system allows the study of virotherapy against PDA in the context of overexpression (80% of PDA patients) or no expression of human mucin 1 (MUC1), a major marker for poor prognosis in patients. In vitro, we tested three VSV recombinants, wild-type VSV, VSV-green fluorescent protein (VSV-GFP), and a safe oncolytic VSV-ΔM51-GFP, against five mouse PDA cell lines that either expressed human MUC1 or were MUC1 null. All viruses demonstrated significant oncolytic abilities independent of MUC1 expression, although VSV-ΔM51-GFP was somewhat less effective in two PDA cell lines. In vivo administration of VSV-ΔM51-GFP resulted in significant reduction of tumor growth for tested mouse PDA xenografts (+MUC1 or MUC1 null), and antitumor efficacy was further improved when the virus was combined with the chemotherapeutic drug gemcitabine. The antitumor effect was transient in all tested groups. The developed system can be used to study therapies involving various oncolytic viruses and chemotherapeutics, with the goal of inducing tumor-specific immunity while preventing premature virus clearance. 相似文献
10.
Timothy B. Curry Madhuri Somaraju Casey N. Hines Cornelius B. Groenewald John M. Miles Michael J. Joyner Nisha Charkoudian 《Obesity (Silver Spring, Md.)》2013,21(3):480-485