全文获取类型
收费全文 | 181365篇 |
免费 | 14336篇 |
国内免费 | 49篇 |
出版年
2018年 | 1810篇 |
2017年 | 1758篇 |
2016年 | 2254篇 |
2015年 | 2141篇 |
2014年 | 2936篇 |
2013年 | 4191篇 |
2012年 | 4803篇 |
2011年 | 5308篇 |
2010年 | 3718篇 |
2009年 | 3353篇 |
2008年 | 4862篇 |
2007年 | 5125篇 |
2006年 | 4821篇 |
2005年 | 4541篇 |
2004年 | 4690篇 |
2003年 | 4597篇 |
2002年 | 4576篇 |
2001年 | 8386篇 |
2000年 | 8579篇 |
1999年 | 6313篇 |
1998年 | 1990篇 |
1997年 | 2035篇 |
1996年 | 1801篇 |
1995年 | 1676篇 |
1992年 | 5198篇 |
1991年 | 5362篇 |
1990年 | 5139篇 |
1989年 | 5116篇 |
1988年 | 4732篇 |
1987年 | 4485篇 |
1986年 | 4076篇 |
1985年 | 4236篇 |
1984年 | 3408篇 |
1983年 | 2911篇 |
1982年 | 1931篇 |
1981年 | 1728篇 |
1980年 | 1718篇 |
1979年 | 3211篇 |
1978年 | 2546篇 |
1977年 | 2278篇 |
1976年 | 2081篇 |
1975年 | 2546篇 |
1974年 | 2885篇 |
1973年 | 2802篇 |
1972年 | 2653篇 |
1971年 | 2415篇 |
1970年 | 2117篇 |
1969年 | 2022篇 |
1968年 | 1906篇 |
1967年 | 1743篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
T I Titova T N Sidorova S A Radkevich N G Antsiferova A F Moroz 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1985,(8):80-84
The influence of immunization with P. aeruginosa vaccine on the immune status of volunteer donors has been studied. Immunization with P. aeruginosa vaccine in doses of 0.5-0.5-1.0 ml at intervals of 7 days has been found to lead to the 13-fold increase of the titer of specific antibodies, lasting for 3-4 months, which ensures the possibility of obtaining anti-P. aeruginosa hyperimmune plasma with standard titers. The injection of P. aeruginosa vaccine to donors leads to the activation of humoral immunity simultaneously with the increase of the absolute and relative number of rosette-forming B-lymphocytes without essential changes in the amount of rosette-forming T-lymphocytes. 相似文献
992.
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
993.
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
994.
Inducible DNA polymerase I synthesis in a UV hyper-resistant mutant of Escherichia coli 总被引:1,自引:0,他引:1
A mutant of Escherichia coli which is more resistant to shortwave UV light than its wild-type parent strain and which can synthesise DNA polymerase I constitutively has been further analysed. It carries two mutational alleles which are located about 1.5 min apart and cotransducible by P1 with the argH locus. The two mutational alleles have been segregated and their analysis shows that one of them is responsible for UV hyper-resistance whereas the other mutation confers UV sensitivity. Recombinant plasmids carrying various sections of the polA regulatory region, linked to a galK gene, were introduced into the mutant strains. Analysis of galactokinase shows that the enzyme activity in the UV hyper-resistant mutant is increased. The results suggest that the synthesis of DNA polymerase I in E. coli is inducible. 相似文献
995.
996.
997.
998.
G A Solov'eva I S Sakharova Ia I Krivokobyl'skaia 《Biokhimii?a (Moscow, Russia)》1982,47(9):1563-1569
The glycogen synthase I--glycogen complex isolated from rabbit skeletal muscles is stable during precipitation with trichloroacetic acid and Sepharose 2B chromatography. The complex catalyzes the synthesis (lengthening) of the alpha-1.4-glucosyl chains when endogenous or exogenous enzyme-free glycogen is used, the initial rates of this synthesis being identical. Preincubation with glycogen does not cause activation of the complex or formation of additional glycogen synthase I--polysaccharide bonds. The complex is characterized by saturation with respect to glycogen; the molar concentration ratios of the non-reducible chain and protein monomer within the complex does not exceed 100. An increase in the length of the synthesized alpha-1.4-glycosyl chains of glycogen results in a decrease of the rate of the glycogen synthase reaction in time. 相似文献
999.
1000.
I B Mikha?lov 《Biulleten' eksperimental'no? biologii i meditsiny》1987,104(11):586-588
It has been shown on frogs with epileptogenic focus induced by the injection of penicillin (1000 U in 0.4 ml) into the hippocamp that preinjection (or injection on the background of the functioning epileptogenic focus) of strophanthin (1.8 and 0.18 microgram/g) or digoxin (1.2 micrograms/g) into spinal lymphaticus sac led to a sharp increase in interparoxysmal epileptiform discharges and electrographic correlates of fits on the ECG. The influence of cardiac glycosides upon the epileptized cerebral neurons is thought to be associated with the capacity of these drugs to inhibit Na+, K+-ATPase of neurons and their axons resulting in the disturbance of cerebral mediator activity. 相似文献