全文获取类型
收费全文 | 13080篇 |
免费 | 2篇 |
国内免费 | 1篇 |
出版年
2012年 | 178篇 |
2011年 | 331篇 |
2010年 | 121篇 |
2008年 | 321篇 |
2007年 | 375篇 |
2006年 | 354篇 |
2005年 | 392篇 |
2004年 | 402篇 |
2003年 | 425篇 |
2002年 | 395篇 |
2001年 | 380篇 |
2000年 | 410篇 |
1999年 | 406篇 |
1998年 | 39篇 |
1992年 | 468篇 |
1991年 | 593篇 |
1990年 | 628篇 |
1989年 | 558篇 |
1988年 | 609篇 |
1987年 | 513篇 |
1986年 | 473篇 |
1985年 | 433篇 |
1984年 | 319篇 |
1983年 | 293篇 |
1982年 | 96篇 |
1981年 | 82篇 |
1980年 | 77篇 |
1979年 | 250篇 |
1978年 | 218篇 |
1977年 | 170篇 |
1976年 | 210篇 |
1975年 | 255篇 |
1974年 | 267篇 |
1973年 | 283篇 |
1972年 | 246篇 |
1971年 | 204篇 |
1970年 | 193篇 |
1969年 | 169篇 |
1968年 | 185篇 |
1967年 | 179篇 |
1966年 | 157篇 |
1965年 | 129篇 |
1959年 | 27篇 |
1958年 | 55篇 |
1957年 | 38篇 |
1956年 | 36篇 |
1955年 | 41篇 |
1954年 | 19篇 |
1952年 | 14篇 |
1951年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
81.
82.
N-methylcytisine--a selective ligand of nicotinic receptors of acetylcholine in the CNS 总被引:1,自引:0,他引:1
Iu G Pliashkevich V P Demushkin 《Biulleten' eksperimental'no? biologii i meditsiny》1987,104(12):690-692
The ability of cytisine and its N-methyl derivatives to bind to nicotinic acetylcholine receptors (nAChR) from different tissues was studied. Cytisine and N-methylcytisine have high affinity (KD = 50 nM) to nAChR from squid optical ganglia. N,N-dimethylcytisine did not show high affinity to this receptor. In the case of nAChR from T. marmorata, cytisine was the only effective inhibitor of 14C-tubocurarine specific binding (Ki = 700 nM). N-methyl- and N,N-dimethylcytisine did not displace 14C-tubocurarine at a concentration of 0.1 mM. The results obtained indicate that there are some differences in the structure of nAChR binding sites from squid and T. marmorata optical ganglia. 相似文献
83.
84.
Iu B Lishmanov T V Fedotova M I Titov 《Biulleten' eksperimental'no? biologii i meditsiny》1989,107(6):704-706
The protective action of enzymatically stable analogue of Leu-enkephalin (D-ala-2-leu5-arg6), injected intraperitoneally, in the course of stress- and epinephrine induced myocardial damage was demonstrated in animal (129 white rats) experiments. Two effect of enkephalin were sufficient for the cardiac protection: enkephalin-stimulated prostacyclin biosynthesis and simultaneous inhibition of thromboxane production. 相似文献
85.
86.
87.
Iu A Belaia V M Bondarenko V G Petrukhin I E Deev 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1982,(8):38-42
Genetic and immunoelectrophoretic studies confirm earlier data on the presence of 2 specific antigens of acidic nature in S. newcastle; one of them is a specific thermolabile K-antigen responsible for type IV specificity of these bacteria. The data concerning the differences in the genetic determinants controlling the synthesis of O- and K-antigens in S. newcastle have been obtained. S. newcastle O- and K-antigens did not react with S. flexneri in the group serum system 3, 4, which indicates that S. newcastle are serologically isolated and form a separate taxonomic group of dysentery bacteria. The existence of cross reactions between S. flexneri and S. newcastle due to the presence of neutral R-core antigens common to these 2 species has been shown . Immunoelectrophoresis in agar is the most promising and informative method in genetic and chemical studies of the antigenic structure of bacteria. 相似文献
88.
O E Kolesova G V Leont'eva L A Apollonova R Kh Chilingirov Iu I Bobkov 《Biulleten' eksperimental'no? biologii i meditsiny》1986,101(3):282-284
The method of intravenous administration of UV-irradiated donor plasma to patients with jaundice of different genesis has been tested in the experiments on rats and used clinically in 20 patients. Biochemical and morphological studies have shown that such treatment causes stable improvement in the liver functional state. 相似文献
89.
L V Antonova A A Kamenski? T I Vlasova N Iu Sarycheva V N Nezavibat'ko 《Biulleten' eksperimental'no? biologii i meditsiny》1986,102(11):569-571
Heptapeptide Met-Glu-His-Phe-Pro-Gly-Pro (ACTH4-10 analog) at a dose of 0.015 mg/kg failed to alter open field behaviour of rats in the first test series. The peptide abolished amphetamine-induced stimulation of the exploratory and grooming behaviour. Extinction of the rats' exploratory behaviour during second test series in the open field (7 days later) was disturbed when haloperidol or apomorphine were injected before the first test series. When the peptide was administered with haloperidol or apomorphine, the extinction tended to become normal. Heptapeptide failed to change noradrenaline, dopamine or 5-hydroxytryptamine content in the rat forebrain. However, this peptide at a concentration of 10(-4) M moderately diminished tyrosine hydroxylation velocity in the rat striatal or hypothalamic synaptosomes, the effect depending on tyrosine concentration. These data suggest the involvement of catecholaminergic component into the heptapeptide action on the behaviour of rats. 相似文献
90.
N K Chenas I A Martsinkiavichene Iu Iu Kulis S A Usanov 《Biokhimii?a (Moscow, Russia)》1987,52(4):643-649
The reactions of NADPH oxidation by quinones and inorganic complexes catalyzed by NADPH: adrenodoxin reductase were studied. The catalytic constant for the enzyme at pH 7.0 is 20-25 s-1; the oxidative constants for the quinones vary from 5 X 10(5) to 1.1 X 10(3) M-1 s-1 and show an increase with a rise in the one-electron acceptor reduction potential. The mode of adrenodoxin reductase interaction with oxyquinones differs from that of the enzyme interaction with alkyl-substituted quinones and inorganic complexes. NADPH competitively inhibits electron acceptors, whereas NADP+ is a competitive inhibitor of NADPH and a uncompetitive inhibitor of electron acceptors. (Ki = 25 microM). The depth of FAD incorporation into the enzyme molecule as calculated according to the outer sphere electron transfer theory is 6.1 A. 相似文献