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61.
Thin sections of the spore of Bacillus thiaminolyticus Matsukawa and Misawa show a characteristic surface structure with five ridges, and a series of three district layers. The outer layer of the spore coat was peeled off by SDS sonic treatment, and than the middle layer was solubilized by alkali extraction of the SDS sonic-treated spore. The spores subjected to these treatments were still refractile, heat resistant, and contained dipicolinic acid, but lost their resistance to mechanical shock. 相似文献
62.
Lawrence W. Adler Tomio Ichikawa Syed M. Hasan Tomofusa Tsuchiya Barry P. Rosen 《Journal of cellular biochemistry》1977,7(1):15-27
Membrane vesicles of Escherichia coli can be produced by 2 different methods: lysis of intact cells by passage through a French pressure cell or by osmotic rupturing of spheroplasts. The membrane of vesicles produced by the former method is everted relative to the orientation of the inner membrane in vivo. Using NADH, D-lactate, reduced phenazine methosulfate, or ATP these vesicles produce protonmotive forces, acid and positive inside, as determined using flow dialysis to measured the distribution of the weak base methylamine and the lipophilic anion thiocyanate. The vesicles accumulate calcium using the same energy sources, most likely by a calcium/proton antiport. Calcium accumulation, therefore, is presumably indicative of a proton gradient, acid inside. The latter type of vesicle, on the other hand, exhibits D-lactate-dependent proline transport but does not accumulate calcium with D-lactate as an energy source. NADH oxidation or ATP hydrolysis, however, will drive the transport of calcium but not proline in these vesicles. Oxidation of NADH or hydrolysis of ATP simultaneous with oxidation of D-lactate does not result in either calcium or proline transport. These results suggest that the vesicles are a patchwork or mosiac, in which certain enzyme complexes have an orientation opposite to that found in vivo, resulting in the formation of electrochemical proton gradients with an orientation opposite to that found in the intact cell. Other complexes retain their original orientation, making it possible to set up simultaneous proton fluxes in both directions, causing an apparent uncoupling of energy-linked processes. That the vesicles are capable of generating protonmotive forces of the opposite polarity was demonstrated by measurements of the distribution of acetate and methylamine (to measure the ΔpH) and thiocyanate (to measure the Δψ). 相似文献
63.
Relationship between phosphate content and immunochemical properties of subfractions of bakers'' yeast mannan. 总被引:3,自引:3,他引:0 下载免费PDF全文
The mannan of bakers' yeast (Saccharomyces cerevisiae) was fractionated on a column of diethylaminoethyl-Sephadex into five subfractions. Phosphate content of these mannan subfractions was proportional to the concentration of NaCl solutions used in the chromatographic separation. Quantitative precipitin reactions showed that the serological reactivities of the subfractions were proportional to the content of phosphate. The result of acetolysis study showed that the amounts of mannotetraose and phosphate-containing oligosaccharide fractions increased proportionally to the acidity, whereas the amount of mannose decreased inversely. The results from quantitative precipitin reaction tests and acetolysis study demonstrated that both phosphate contents and multiplicity of branching moieties of mannan subfractions increased proportionally, i.e., micro-heterogeneity concerning the acidity comprised in the parent bulk mannan is not attributable merely to the coexistence of molecular species containing different amounts of phosphate but also to the presence of more of the branching moieties. 相似文献
64.
Pig NADPH-adrenodoxin reductase was crystallized from pig adrenocortical mitochondria and its physicochemical properties were investigated. Pig NADPH-adrenodoxin reductase is a typical flavoprotein. Its optical absorption spectrum showed peaks at 272, 377, and 450 nm in the oxidized form. The adrenodoxin reductase contained one FAD per mol. The molecular weight was 49,000. The isoelectric points of the adrenodoxin reductase and its complex with adrenodoxin were 5.3 and 4.6, respectively. Pig NADPH-adrenodoxin reductase, unlike bovine NADPH-adrenodoxin reductase, was found to be free of carbohydrate. The fluorescences of tryptophanyl residues and FAD of the adrenodoxin reductase were quenched by holo- and apo-adrenodoxins. The NADPH-binding site of the adrenodoxin reductase was examined by photooxidation and selective chemical modifications with diethyl pyrocarbonate and sulfhydryl reagents. The results indicate that a histidyl and a cysteinyl residue of the adrenodoxin reductase are essential for the NADPH-binding site. The circular dichroism spectrum of the adrenodoxin reductase showed negative ellipticity in the visible region. Spur formation was observed between pig and bovine NADPH-adrenodoxin reductases against the antibody to bovine NADPH-adrenodoxin reductase in Ouchterlony double-diffusion agar plates. The antibody did not interact with spinach ferredoxin-NADP+ reductase. 相似文献
65.
66.
Changes in actin-related gelation of crude cell extracts during differentiation of myeloid leukemia cells 总被引:1,自引:0,他引:1
Gelation of extracts of a myeloid leukemia cell line (Ml) was compared before and after differentiation induced with conditioned medium (CM) from rat embryo cells. Although an extract of Mml cells, a macrophage line derived from Ml line, gelled when warmed in the presence of 2 mM MgCl2, undifferentiated Ml cells gelled only after dialysis and a supplement of exogenous actin. After differentiation had been induced, an addition of exogenous actin, but not dialysis, was needed for gelation. Small amounts of KCl always inhibited the gelation of the control Ml cell extracts, but they promoted gelation of the CM-treated Ml and Mml cell extracts. Thus, the dialysis required for gelation of the control Ml cell extract appears to be necessary for the exclusion of endogenous KCl. Several possible mechanisms for the KCl control of gelation, as well as different requirements of exogenous actin needed for gelation are discussed based on the results of our experiments. 相似文献
67.
Yasuko Mizuno Atsushi Ichikawa Kenkichi Tomita 《Prostaglandins & other lipid mediators》1983,26(5):785-795
The effect of 7-fluoro proscyclilin (PGI2-F), a chemically stable analogue of prostacyclin, on cAMP accumulation in and [3H]PGE binding to mastocytoma P-815 cells was compared with those of the Na salt and methyl ester of prostacyclin (PGI2Na or PGI2Me), which are rapidly inactivated in aqueous solution or metabolized in the tissue.PGIF was as effective as PGI2Me, and slightly less effective than PGI2Na in stimulating cAMP accumulation in mastocytoma cells and rabbit platelets. PGI2F was also more stable than PGI2Me or PGI2Na, and retained its original cAMP elevating activity even after incubation with or without cells for 4 h at 37°C. Cells which had been exposed to PGI2F and then washed free of unbound reagent continued to produced cAMP for more than 3 h. PGI2F was also as effective as PGE1 or PGE2 in displacing [3H]PGE2 bound to the cells. Non-competitive inhibition by PGI2F or PGI2Me of [3H]PGE2 binding to the cells, with apparent Kis of 1.29 μM and 1.13 μM, respectively, indicates the presence of different receptors for PGE2 and for PGI2F or PGI2Me in mastocytoma P-815 cells. 相似文献
68.
Michinori Ichikawa Masashi Urayama Gen Matsumoto 《The Journal of membrane biology》1991,120(3):211-222
Summary The effects of calmodulin (CaM) antagonists (W-7, W-5, trifluoperazine, chlorpromazine, quinacrine, diazepam, propericyazine and carmidazolium) on the sodium and potassium channels were studied on the intracellularly perfused and voltage-clamped giant axon of the squid. It was found that the drugs are more potent blockers of the sodium current than of the potassium current. The drugs also reduce the sodium gating current. The blockage of the sodium and gating current can be explained by assuming that the drugs interact with the sodium gating subunit in one of its closed states. The site of action is probably the intracellular surface of the axolemma where presumably a Ca2+-calmodulin complex can be formed. 相似文献
69.
K Ichikawa K Hashizume M Kobayashi Y Nishii A Sakurai T Takeda S Suzuki T Yamada 《Endocrinologia japonica》1992,39(2):203-207
Human beta thyroid hormone receptor (c-erb A beta protein) produced by an Escherichia coli expression system was purified by sequential column chromatography followed by electroelution from an electrophoresis gel and an antibody was prepared. The antibody recognized a 56 kDa protein band in a partially purified rat hepatic nuclear thyroid hormone receptor fraction on Western blotting. Although multiple bands appeared on Western blotting of crude rat hepatic receptor preparations, a 56 kDa band was the most prominent and preadsorption of the antibody by purified c-erb A protein resulted in almost complete disappearance of the 56 kDa band, indicating that the 56 kDa band was formed by a specific antigen-antibody interaction. Furthermore, the 56 kDa protein appeared to co-elute with 3, 5, 3'-triiodo-L-thyronine binding activity in hydroxylapatite, Sephacryl S-200, and DNA-cellulose column chromatography of rat hepatic nuclear receptor, and sequential column purification resulted in selective enrichment of the 56 kDa band. These results suggest that the 56 kDa protein may be the major component of the rat hepatic thyroid hormone receptor. 相似文献
70.
Steroid saponins from Polygonatum kingianum. 总被引:13,自引:0,他引:13
Four new steroid saponins, kingianosides A-D, were isolated from the rhizome of Polygonatum kingianum, together with two known steroid saponins. On the basis of chemical and spectral evidence, the structures of kingianosides A-D were established as gentrogenin 3-O-beta-D-glucopyranosyl (1-->4)-beta-D-galactopyranoside, gentrogenin 3-O-beta-D-glucopyranosyl(1-->4)-beta-D-fucopyranoside, 26-O-beta-D-glucopyranosyl-22-hydroxy-25(R)-furost-5-en-12-on-3 beta, 22-diol 3-O-beta-D-glucopyranosyl(1-->4)-beta-D-galactopyranoside and 26-O-beta-D-glucopyranosyl-22-hydroxy-25(R)-furost-5-en-12-on-3 beta,22-diol 3-O-beta-D-glucopyranosyl(1-->4)-beta-D-fucopyranoside, respectively. 相似文献