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151.
Naoko Yuno Ohta Yoshiko Segawa Sonoe Fujii Yumiko Fujiwara Mariko Kuchiba Teruyoshi Matoba 《Bioscience, biotechnology, and biochemistry》2013,77(7):1747-1754
The effect of various reagents on the formation and stability of heat-induced gels of sesame 13S globulins were investigated. Electrostatic interaction, the hydrophobic bond and the disulfide bond were important for forming the network structure of gels, and the hydrogen bond also had an influence on the formation of the gel. Hydrophobic bonds mainly contributed to the stability of the gel. Subunit analyses of the proteins solubilized from the gels showed the presence of a free acidic subunit (AS) and basic subunit (BS), a polymer of AS, a dimer of BS and the dimer of a fragment from AS or BS. From the results, sulfhydryl-disulfide exchange reactions during gelation are suggested. 相似文献
152.
Masashi Miyano Hajime Matsushita Norio Yasumatsu Koh Nishida 《Bioscience, biotechnology, and biochemistry》2013,77(10):2205-2206
Allyl sulfides such as diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS), typical flavor components of Allium vegetables, have been shown to inhibit benzo[a]pyrene (B[a]P)-induced carcinogenesis in animal models. As a possible mechanism of this inhibition, the effect of these volatile substances on cytochrome P450 (CYP)1 (CYP1A1, 1A2 and 1B1)-mediated bioactivation of B[a]P was investigated using a human hepatoma cell model (HepG2). DADS and DATS inhibited the B[a]P-induced ethoxyresorufin O-deethylase (EROD) activity, a marker enzyme for CYP1, by 30-90% and 70-95% at 100-1,000 μM concentration, respectively. The cell viability, an indicator of the capacity to inhibit B[a]P bioactivation, was increased by treatments of 100-1,000 μM DADS and 10-100 μM DATS. Immunoblot results indicated that the B[a]P inducible CYP1A2 protein was suppressed by 100-1,000 μM of DADS and 10-100 μM of DATS, but CYP1A1 and 1B1 were not detectable in any microsomes. Analysis of B[a]P metabolites revealed that the level of 7,8-diol formed was significantly reduced in the DADS and DATS treated microsomes as compared to the control. The level of 9,10-diol and 4,5-diol formed was also lowered by the allyl sulfide treatments. These results suggest that the protective mechanism of allyl sulfides on B[a]P-induced carcinogenesis is possibly related with the modulation of CYP1-mediated bioactivation of B[a]P. 相似文献
153.
Several glycolipids were isolated from Spirulina maxima, an edible blue-green algae, by systematic fractionation with different solvents. Structural investigation by using methylation, GC-MS, and enzymic techniques indicated that the major glycolipids are O-β-d-galactosyl-(1→l′)-2′, 3′-di-O-acyl-d-glycerol, O-α-d-galactosyl-(l-→6)-O-β-d-galactosyl-(1→l′)-2′,3′-di-O-acyl-d-glycerol and 6-sulfo-O-α-quinovosyl-(l→l′)-2′, 3′-di-O-acyl-d-glycerol. Main fatty acid components of these glycolipids were identified as palmitic acid and linoleic or linolenic acid. Based on-these fatty acid compositions, Spirulina glycolipids were compared with those in higher plants. 相似文献
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157.
Twelve strains of lactose-fermenting yeast isolated from raw milk were evaluated on β-galactosidase producing ability. The enzymes from the four strains (Tolulopsis versatilis M6, Tolulopsis sphaerica J28, Candida pseudotropicalis B57 and A60), selected by high productivity, showed very similar properties and were characterized by a pH optimum of 7.0 or 7.5 and a relatively low optimal temperature of 30°C. The molecular weights were estimated by gel filtration to be 200,000-233,000. The Km values for o-nitrophenyl-β-d-galactopyranoside were 3.45 mm, 2.09 mm, 3.45 mm and 2.82 mm for enzymes from M6, J28, B57 and A60, respectively. All enzymes were activated by Mn2+ and inhibited by Mg2+, Zn2+ and Ca2+. The enzymes are sulfhydryl dependent and were completely inhibited by Hg2+ and sulfhydryl reagents. The yeasts may be a potential source for the enzyme for industrial use. 相似文献
158.
Etsuro Sugimoto Masaaki Yoshikawa Yutaka Nishida Hideo Chiba 《Bioscience, biotechnology, and biochemistry》2013,77(12):2497-2504
It was indicated from fluorescence spectra and fluorescence titration that a hydrophobic probe, 1-anilino-8-naphthalenesulfonate (ANS), binds to casein components (αs-, β- and κ-caseins). Fluorescence intensity and affinity of ANS-κ-casein complex were larger than that of ANS-αs- and ANS-β-casein complexes. Enhancements of fluorescence intensity of complexes of casein components were observed by the addition of KCI or CaCl2. Reason for the enhancement was postulated to be the increase of the quantum yield of the ANS fluorescence caused by the environmental change of ANS binding region of the casein components.Marked increase of sedimentation coefficient of β-casein in the presence of KCl or CaCl2 at 10°C was caused by the addition of ANS. This may be responsible for the stimulation of the Ca-dependent precipitation of β-casein by the addition of ANS.It was found that αs · κ-association was prevented by ANS and that hydrophobic interaction have an important role for αs · κ-association. 相似文献
159.
The reversible interaction between dextran sulfate (D) and the low density lipoprotein of human serum (P) was investigated by sedimentation velocity. Analysis of the velocity patterns of dextran sulfate—lipoprotein mixtures revealed that the maximum number of binding sites on dextran sulfate molecule is approximately 6. It was also shown that the species of the complex formed is affected by the mixing ratio of the two constituents: at the molar ratio (P/D) 0.69, the complex exists in average as DP1.6 and at 0.98 as DP2.2. The linear increment of sedimentation coefficient of the complex due to the binding of one lipoprotein molecule was 7.8S. Finally, the mechanism of precipitation of the complexes was discussed. 相似文献
160.
Ryotaro Hara Naoko Uchiumi Naoko Okamoto 《Bioscience, biotechnology, and biochemistry》2013,77(8):1384-1388
We evaluated the substrate specificities of four proline cis-selective hydroxylases toward the efficient synthesis of proline derivatives. In an initial evaluation, 15 proline-related compounds were investigated as substrates. In addition to l-proline and l-pipecolinic acid, we found that 3,4-dehydro-l-proline, l-azetidine-2-carboxylic acid, cis-3-hydroxy-l-proline, and l-thioproline were also oxygenated. Subsequently, the product structures were determined, revealing cis-3,4-epoxy-l-proline, cis-3-hydroxy-l-azetidine-2-carboxylic acid, and 2,3-cis-3,4-cis-3,4-dihydroxy-l-proline. 相似文献