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101.
A Wada M Okamoto Y Nonaka T Yamano 《Biochemical and biophysical research communications》1984,119(1):365-371
[3H]Corticosterone was incubated with cytochrome P-45011 beta purified to electrophoretic homogeneity from bovine adrenocortical mitochondria, and the reaction products were analyzed by high performance liquid chromatography. The production of aldosterone (21.2 pmol/nmol P-450/min) and 18-hydroxycorticosterone (1.17 nmol/nmol P-450/min) was observed. When lipidic extracts from mitochondria of bovine adrenocortical zona glomerulosa were added to the reaction mixture, the rate of production of aldosterone was increased 28-fold. When [3H]18-hydroxycorticosterone was incubated with cytochrome P-45011 beta, the amount of aldosterone produced was 55.7 pmol/nmol P-450/min in the absence of the lipidic extracts and the enhancing effect of the lipidic extracts was 4-fold. 相似文献
102.
103.
According to the measurement of ESR spectrum, Ca2+ induced conformational change of spin-labeled g2 bound to myosin in the presence of 1 mM Mg2+. The half-maximal changes were observed at pCa 6.8 and at pCa 3.7. Spin-labeled phosphorylated g2 bound to myosin showed one transition at pCa 4.5, which shifted to pCa 6.5 after the dephosphorylation with E. coli alkaliphosphatase. 相似文献
104.
H Okamoto N Sone H Hirata M Yoshida Y Kagawa 《The Journal of biological chemistry》1977,252(17):6125-6131
1. The membrane-integrated portion (TF0) of the proton translocating ATPase complex (TF0-F1) of the thermophilic bacterium PS3 was highly purified. Its proton-conducting activity was investigated in vesicles reconstituted from TF0 and phospholipids (TF0 vesicles). 2. The rate of proton conduction through TF0 was proportional to the membrane potential imposed (6H+ uptake/s/TF0 molecule with 103 mV at pH 8.0). The pH profile of the rate revealed that a proton, not a hydroxy ion, was the true substrate conducted and that there was a monoprotic proton binding site in TF0 (pKa = 6.8). The temperature coefficient of proton conductance of TF0 showed a considerable variation depending on the phospholipids of the vesicles with respective transition temperatures. 3. Passive proton conduction through TF0 was inhibited stoichiometrically by addition of either the soluble ATPase portion (TF1) of TF0-F1, or an energy transfer inhibitor dicyclohexylcarbodiimide or an antibody against TF0. 4. The proton conductance of TF0 was concluded to represent its intrinsic activity in the original TF0-F1 complex. 相似文献
105.
U Okamoto K Sasaki N Nagao I Naiki Y Nagamatsu 《Nihon seirigaku zasshi. Journal of the Physiological Society of Japan》1982,44(11):633-641
Non-plasmin fibrinolysis enzyme was extracted from the lung and spleen of conventional rats (Thrombos. Haemostas., 1979), although the enzyme was not found in germfree rats, suggesting the possibility that the enzyme may participate in the defence mechanism of the body. The present study was made in an attempt to determine the behavior of non-plasmin fibrinolysis enzyme of the lung tissue in the DIC model of conventional rats induced by a single injection of bacterial endotoxin. The plasminogen-activator activity of the lung tissue, and the fibrinogen level, platelet count, urea nitrogen and plasminogen-activator activity in the blood were also measured. Examination of the lung tissue in the DIC rats indicated a remarkable increase in non-plasmin fibrinolysis activity and a disappearance of plasminogen-activator activity. Inhibitor studies using t-AMCHA and DFP demonstrated that the increased non-plasmin fibrinolysis activity was not derived from activated plasmin, but from serine protease. The disappearance of plasminogen-activator activity in the lung and increase of plasminogen-activator activity in the blood suggested a release of the activator from the lung into the blood due to the endotoxin injection. 相似文献
106.
Induction of Bacillus subtilis sporulation by decoyinine and the concomitant disappearance of ppGpp in vegetative cells 总被引:1,自引:0,他引:1
Sporulation of Bacillus subtilis, growing exponentially in the presence of rapidly metabolizable nutrients, was induced by addition of decoyinine (an antibiotic inhibitor of GMP synthesis), and intracellular amounts of ppGpp were determined after 2 M formic acid extraction by polyethyleneimine (PEI)-cellulose thin-layer chromatography. Consequently, it was found that the ppGpp in vegetative cells abruptly disappeared after the addition of decoyinine. This indicates that the disappearance of ppGpp is closely correlated to the initiation of B. subtilis sporulation. 相似文献
107.
Enzymic mechanism of starch breakdown in germinating rice seeds : 11. Ultrastructural changes in scutellar epithelium 总被引:4,自引:2,他引:2
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The ultrastructural changes occurring in the scutellar epithelium cells of rice seeds have been studied during germination and early seedling growth. During this time, several prominent structural changes occur, including (a) formation, development, and proliferation of organelles such as mitochondria, rough endoplasmic reticulum, free ribosomes, and Golgi apparatus; (b) folded structural modification of plasmamembranes in later stages; and (c) conspicuous decrease in lipid-storing spherosomes. Glyoxysome-like electron dense particles are detectable but their formation is much less prominent. It is conceivable that all these structural changes are related to the enhancement of the metabolic activities of the epithelial cells including the synthesis of hydrolytic enzymes such as α-amylase and their secretion into the endosperm tissues. Some enzyme activities characteristic of mitochondria and glyoxysomes have been determined using the crude scutellar extracts, and the results dealing with the low activities of the glyoxylate cycle enzymes and palmitoyl-coenzyme A oxidase appear to indicate that fatty acid breakdown is possibly via mitochondrial β-oxidation, although we reserve a definitive conclusion on the glyoxysomes being nonfunctional in fatty acid oxidation in rice seedlings. 相似文献
108.
In regenerating rat liver slices 24 h after partial hepatectomy, the incorporation of [1-14C]glucosamine into 'free sialic acid' (N-acetylneuraminic acid + CMP-N-acetylneuraminic acid) decreased to below 50% of the control values and the incorporation into protein-bound sialic acid decreased to the same extent. The incorporation of [14C]glucosamine into 'free sialic acid' decreased during the period from 6 to 47 h after hepatectomy, showing a minimum at 12 h, and recovered to the control value by 96 h. At 12 h, the activities of UDP-N-acetylglucosamine 2-epimerase (UDP-2-acetoamido-2-deoxy-D-glucose 2-epimerase, EC 5.1.3.14) and N-acyl-D-mannosamine kinase (ATP: 2-acylamino-2-deoxy-D-mannose 6-phosphotransferase, EC 2.7.1.60) in the liver were significantly decreased. The amount of protein-bound sialic acid in the liver was not changed after partial hepatectomy, but the amount in plasma was changed, with a similar pattern to that of the incorporation of [14C]glucosamine into slice 'free sialic acid'. These results indicate that the synthesis of sialic acid in the liver much decreases in the early stage of regeneration and that this may be correlated with the decreased synthesis of plasma sialoglycoproteins. 相似文献
109.
Sachiko Kuno Tetsuo Toraya Saburo Fukui 《Archives of biochemistry and biophysics》1980,205(1):240-245
The apoenzyme of diol dehydrase was inactivated by two arginine-specific reagents, 2,3-butanedione and phenylglyoxal, in borate buffer. In both cases, the inactivation followed pseudo-first-order kinetics. Kinetic data show that the incorporation of a single reagent molecule per active site of the enzyme is necessary for the complete inactivation. The modification with 2,3-butanedione was reversed by dilution of the reagent and borate concentrations (65% activity recovered). 1,2-Propanediol (substrate) partially protected the enzyme against inactivation. The holoenzyme was almost insensitive to 2,3-butanedione and phenylglyoxal, indicating that the essential arginine residue is prevented from the attack of these reagents either by direct blockage with the bound coenzyme or by an indirect conformational change caused by coenzyme binding. The inactivation of diol dehydrase by 2,3-butanedione did not result in dissociation of the enzyme into subunits. From these results, we concluded that the essential arginine residue is located at or in close proximity to the active site of diol dehydrase. 相似文献
110.
Hiroshi Yamamoto Hiroshi Okamoto 《Biochemical and biophysical research communications》1980,95(1):474-481
Picolinamide, 2-pyridinecarboxylic acid amide, was found to be a strong inhibitor of poly (ADP-ribose) synthetase of nuclei from rat pancreatic islet cells. Another experiment using isolated pancreatic islets of rats showed that picolinamide protects against streptozotocin-induced depression of proinsulin synthesis as well as against streptozotocin-induced reduction of NAD content. The protection by picolinamide against the NAD depression was considered to be due to the blockage of an increased degradation of NAD mediated by a streptozotocin-induced increase in poly (ADP-ribose) synthetase activity. A possible mechanism of streptozotocin diabetes and its prevention is discussed. 相似文献