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1.
A V Stulovski? I V Vozny? E V Rozengart A A Suvorov A E Khovanskikh 《Ukrainski? biokhimicheski? zhurnal》1992,64(2):94-98
Three reactions (nucleophile substitution, thiolysis and N-deoxygenation) catalyzed by rat liver glutathione transferase have been studied using several N-heterylazimine inhibitors. The inhibitors are sharply different in their effectiveness in the transferase reactions. Their efficiency depends on their structure. The mechanism which underlies the found regularities is suggested. 相似文献
2.
Decarbamylation rate of membrane-bound methyl- and dimethyl-carbamylated acetylcholinesterase of human erythrocytes and bovine brain is reliably 1.1-1.6 times lower than that of the soluble enzyme. Such reversible inhibitors as tacrine (of non-competition action), ambenonium (mixed action) and galanthamine (competitive type of action) decelerate the decarbamylation rate of acetylcholinesterase. At pH 6 tacrine inhibits the reduction rate of soluble acetylcholinesterase activity of human erythrocytes more intensively than that of membrane-bound acetylcholinesterase. No differences in decarbamylation rate were found for the both forms of the enzyme at pH 8. Tacrine, a non-competitive inhibitor in concentrations below the inhibition constant (Ki = 1.4 x 10(-7) M) exerts the most intensive effect on the decarbamylation rate of methyl- and dimethylcarbamylated acetylcholinesterase of the mouse brain, while ambenonium and galanthamine in concentrations much (tens times) exceeding their Ki (3.1 x 10(-10) M and 4.4 x 10(-7) M, respectively) provide a decrease of the decarbamylation rate. 相似文献
3.
B S Zhorov E V Rozengart V A Govyrin N V Khromov-Borisov N B Brovtsyna 《Molekuliarnaia biologiia》1975,9(6):820-827
Conformational possibilities of pirrolidine analogues of acetylcholine beta-(N-methyl pirrolidinium)-ethyl ester of acetic acid and beta-(N-ethyl pirrolidinium)-ethyl ester of acetic acid and beta-(N-ethyl pirrolidinium)-ethyl ester of acetic acid were investigated by the method of atomic potentials. The conformational energy was considered as a sum of non-bonded and electrostatical interactions, torsional energy and distortions of bond angles. It has been shown that the replacement of the nitrogen methyl group to ethyl group results in decrease of the average barrier height between two gauche conformations of the O--C--C--N fragment. Comparison of conformational properties of some cholinesterase substrates permit to draw a suggestion that the barrier height influences the rate of the enzymatic hydrolysis. 相似文献
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N. E. Basova B. N. Kormilitsyn A. Yu. Perchenok E. V. Rozengart V. S. Saakov A. A. Suvorov 《Journal of Evolutionary Biochemistry and Physiology》2018,54(1):22-29
We report a pioneering analysis of the interaction between mammalian cholinesterases and 36 acylates and thioacylates of ammonium alcohols with different structure of an alkyl chain between ammonium and etheric atoms and with different structure of a cyclic ammonium group. Among these ethers, which were both substrates and reversible inhibitors of erythrocyte cholinesterase and serum butyrylcholinesterase, specific effectors of both enzymes were identified. 相似文献
6.
E. V. Rozengart N. E. Basova B. S. Zhorov S. N. Moralev V. S. Saakov A. A. Suvorov A. E. Khovanskikh 《Journal of Evolutionary Biochemistry and Physiology》2003,39(4):393-404
Study of spatial structure of biologically active guanidine derivatives by the method of molecular mechanics has shown that in an anticoccidial drug, 1,3-bis ( p-chlorobenzylidenamino)guanidine (Cl-BAG) the most preferable are convolute conformations, in which the chlorine atoms that are distant in the valent chain are approached to each other at a distance of 3.7 . This indicates predisposition of the optimal conformations to form chelate complexes with ions of metals, which is confirmed by comparative spectrophotometric studies of the second derivative of differential UV-spectra of Cl-BAG in the presence and absence of calcium ions. Its derivative without chlorine (BAG) is unable to bind Ca2+ and has been shown to have no anticoccidial action, which associates the biological potency with the presence of calcium-binding ability of the compounds. The capability of Cl-BAG for chelation depends essentially on nature of the chelated metal ion. The antienzyme testing of inhibiting action of the guanidine derivatives toward cholinesterases of human erythrocytes, horse blood serum, mink brain and serum, optic ganglia of the Pacific squid Todarodes pacificus has revealed difference between the enzymes due to possibility of redistribution of the positive charge between the guanidinium fragment and amino groups and a change of the degree of charge delocalization. 相似文献
7.
E. V. Rozengart N. E. Basova A. A. Suvorov 《Journal of Evolutionary Biochemistry and Physiology》2002,38(3):270-277
A study is carried out as a development of A.P. Brestkin's concept of mechanism of irreversible inhibition of cholinesterases (ChE) by organophosphorus inhibitors (OPI) with taking into account reversibility of the first stage of this reaction, which has made it possible to determine individual constants of separate stages of the process. For the first time, a comparative study is performed on horse blood serum BuChE, human erythrocyte AChE, and ChE of optical ganglia of Pacific squid Todarodes pacificus. Besides, the OPI set is enlarged essentially due to use of some highly specific inhibitors of each of the enzymes. To evaluate the cholinesterase activity, chromogenic indophenol esters are used as substrates. For each of the studied ChE, differences in sensitivity to the studied OPI are realized only in values of the kinetic constant of formation of the enzyme-inhibitor complex (k
5), whereas the rate constants of dissociation of this complex to initial components (ChE and OPI) (k
–5) and of process of its transformation into phosphorylated ChE (k
6) are close to each other by the values, values of these constants k
–5 and k
6 for different enzymes also being similar. Some statements about the molecular mechanism of the cholinesterase catalysis are formulated. It is suggested that the revealed elements of similarity of different ChE are realized in the work of the catalytic machine of active centers of the enzymes. 相似文献
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