全文获取类型
收费全文 | 2273篇 |
免费 | 109篇 |
国内免费 | 62篇 |
专业分类
2444篇 |
出版年
2023年 | 18篇 |
2021年 | 36篇 |
2020年 | 31篇 |
2019年 | 43篇 |
2018年 | 66篇 |
2017年 | 51篇 |
2016年 | 62篇 |
2015年 | 48篇 |
2014年 | 73篇 |
2013年 | 207篇 |
2012年 | 70篇 |
2011年 | 102篇 |
2010年 | 92篇 |
2009年 | 71篇 |
2008年 | 77篇 |
2007年 | 52篇 |
2006年 | 48篇 |
2005年 | 53篇 |
2004年 | 52篇 |
2003年 | 60篇 |
2002年 | 73篇 |
2001年 | 28篇 |
2000年 | 44篇 |
1999年 | 21篇 |
1992年 | 44篇 |
1991年 | 50篇 |
1990年 | 44篇 |
1989年 | 51篇 |
1988年 | 55篇 |
1987年 | 50篇 |
1986年 | 41篇 |
1985年 | 48篇 |
1984年 | 38篇 |
1983年 | 27篇 |
1982年 | 22篇 |
1981年 | 25篇 |
1980年 | 19篇 |
1979年 | 27篇 |
1978年 | 24篇 |
1977年 | 26篇 |
1976年 | 31篇 |
1975年 | 24篇 |
1974年 | 31篇 |
1973年 | 30篇 |
1972年 | 33篇 |
1971年 | 19篇 |
1970年 | 20篇 |
1969年 | 20篇 |
1968年 | 21篇 |
1966年 | 24篇 |
排序方式: 共有2444条查询结果,搜索用时 15 毫秒
1.
2.
T L Marshak M Sh Avrushchenko 《Biulleten' eksperimental'no? biologii i meditsiny》1986,102(10):477-479
The changes in the size of Purkinje cell (PC) nucleolus in the lateral and medial cerebellum zones were studied in dogs with different degree of neurologic status recovery after clinical death of various etiology and duration. PC always possess one nucleolus in the control and experimental groups. In the case of complete neurologic status recovery of animals the area of PC nucleolus increases in both zones studied, irrespective of the cause of clinical death. In the case of neurologic disorders the increase in PC nucleolus area is clearly expressed only in the medial zone of the cerebellum, being insignificant in the lateral zone. It is suggested that adaptive characteristics of PC are distinct in the two compared zones, which leads to greater PC vulnerability in the lateral zone during deep hypoxia. 相似文献
3.
S. M. Pershin E. Sh. Ismailov Z. G. Suleimanova Z. N. Abdulmagomedova D. Z. Zagirova 《Biophysics》2014,59(2):334-338
It has been experimentally established that cultivation of yeast cells in depleted, dietary or normal nutrient aqueous solutions enriched with ortho-H2O spin isomers is accompanied by an increase in the amount of carbon dioxide produced by the cells and an increase in their biomass. It has been revealed that the rate of metabolic processes and biological activity depends on the quality of nutrition and enhances in time in both nutrient solutions. In contrast, the reproductive function and the rate of cell division are insusceptible to the components of nutrition, but intensified in a solution enriched with ortho-H2O similar to retardation of aging. The observed effects are discussed in assumption that an increase of a portion of ortho-H2O molecules occurs in the neighborhood of water channels in the cell membrane that let through only monomers of H2O and determine the rate vicinity of metabolic processes. 相似文献
4.
V M Morogova R Sh Magazov A V Dulina D V Krutilina R S Shafeeva 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1985,(12):65-67
The production of virus-neutralizing antibodies in high titers has been found to occur in persons immunized with tissue-culture rabies vaccines, concentrated and non concentrated, intramuscularly in a dose of 1 ml in accordance with reduced immunization schedules. 相似文献
5.
Some properties of hexameric purine nucleoside phosphorylase II (EC 2.4.2.1) from Escherichia coli K-12 were studied. The enzyme obeys the Michaelis-Menten kinetics with respect to purine substrates (Km for inosine, deoxyinosine and hypoxanthine are equal to 492, 106 and 26.6 microM, respectively) and exhibits negative kinetic cooperativity towards phosphate and ribose-1-phosphate. The Hill coefficient is equal to approximately 0.5 for both substrates. Hexameric purine nucleoside phosphorylase II is not a metal-dependent enzyme; its activity is inhibited by Cu2+, Zn2+, Ni2+ and SO4(2-). The enzyme is the most stable at pH 6.0; it contains essential thiol groups. All substrates partly protect the enzyme against inactivation by 5.5'-dithiobis(2-nitrobenzoic acid) and heat-inactivation and, with the exception of phosphate-against inactivation by p-chloromercuribenzoate. Hypoxanthine, especially in combination with phosphate, afford the best protection against inactivation. 相似文献
6.
7.
A Sh Byshevski? G S Solov'ev S L Galian V G Solov'ev S V Solov'ev 《Biulleten' eksperimental'no? biologii i meditsiny》1992,114(9):262-265
In experiment on white rats it was shown that preventive 12-day administration of vitamins A, E, C, P decreases the death rate of animals with exogenous thromboplastinemia and reduces hemocoagulative changes, microcirculation disorders, destructive changes of functionally active elements of inner organs. The protective effect of the above vitamins combination in thromboplastinemia is promoted by hypoactivity of platelet aggregation, by low thromboplastic activity of erythrocytes, by limited destruction of vascular endothelium. 相似文献
8.
9.
Corynebacterium equi IFO 3730 was found to oxidize a wide variety of sec-alcohols, including alkanols, substituted alkanols, alkenols and cyclic alcohols, in moderate to high yields. Among them, the sec-alcohols which have longer carbon chains were oxidized more smoothly than those with smaller numbers of carbon. Although both enantiomers of unsymmetrically disubstituted carbinols were oxidized, the S form of 2-dodecanol was converted to the corresponding ketone a little faster than the other enantiomer. 相似文献
10.
T P Kliushnik S G Voloshchuk M V Aksenova G Sh Burbaeva 《Biulleten' eksperimental'no? biologii i meditsiny》1985,99(2):179-180
IEA of brain specific antigen 10-40-4 in human and animal organs and tissues was elaborated. The method permits measuring the concentration of the antigen within the range from 1 to 120 ng/ml. The use of the method made it possible to confirm brain specificity of protein 10-40-4, since its brain content is 1500 to 2000 times higher than in other organs, and to estimate the percentage of cross-reaction between antigenic determinants of brain specific antigen 10-40-4 from different species of animals. 相似文献