全文获取类型
收费全文 | 1994篇 |
免费 | 41篇 |
国内免费 | 63篇 |
专业分类
2098篇 |
出版年
2023年 | 24篇 |
2022年 | 50篇 |
2021年 | 53篇 |
2020年 | 30篇 |
2019年 | 45篇 |
2018年 | 47篇 |
2017年 | 35篇 |
2016年 | 47篇 |
2015年 | 41篇 |
2014年 | 60篇 |
2013年 | 99篇 |
2012年 | 50篇 |
2011年 | 95篇 |
2010年 | 61篇 |
2009年 | 50篇 |
2008年 | 64篇 |
2007年 | 41篇 |
2006年 | 44篇 |
2005年 | 47篇 |
2004年 | 48篇 |
2003年 | 32篇 |
2002年 | 46篇 |
2001年 | 28篇 |
2000年 | 38篇 |
1992年 | 39篇 |
1991年 | 49篇 |
1990年 | 44篇 |
1989年 | 50篇 |
1988年 | 56篇 |
1987年 | 50篇 |
1986年 | 41篇 |
1985年 | 51篇 |
1984年 | 39篇 |
1983年 | 24篇 |
1982年 | 19篇 |
1981年 | 19篇 |
1980年 | 18篇 |
1979年 | 23篇 |
1978年 | 24篇 |
1977年 | 21篇 |
1976年 | 26篇 |
1975年 | 23篇 |
1974年 | 30篇 |
1973年 | 26篇 |
1972年 | 32篇 |
1971年 | 19篇 |
1970年 | 19篇 |
1969年 | 20篇 |
1968年 | 21篇 |
1966年 | 24篇 |
排序方式: 共有2098条查询结果,搜索用时 0 毫秒
1.
The morphology and innervation of the six oculomotor muscles in the gobiid fishTridentiger trigonocephalus are described. Every rectus muscle is composed of two types of muscle fibres. Muscles attach onto the cartilaginous or fibrous
sclerotica. Oblique muscles attach onto the ethmoidal plate; recti muscles attach onto the parasphenoid or a thick fibrous
membrane. There is no myodome. The common oculomotor nerve is composed of four bundles, the trochlear and the externus of
two. The two kinds of fibres of the lateral rectus and the two distinct bundles of the nerve VI suggest a possible homology
between this muscle in fishes and the lateral rectus+retractor bulbi in mammals. 相似文献
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.
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
4.
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
5.
6.
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
7.
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
8.
V V Vysotski? I Sh Vaisman O G Efimova N V Chemurzieva 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1985,(9):54-60
The characteristic feature of replicas obtained from the freeze-fractures of B. pertussis unfixed cultures developing on casein charcoal agar for 1-7 days is the associative growth of highly polymorphic cells, ensured by the ramified system of intercellular connections (IC) formed by the derivatives of the outer layers of the cell wall. This proves that the associative location of bacterial cells, linked by numerous IC, in the preparation is not the artefact appearing in the process of their chemical fixation. In replicas obtained from the freeze-fractures of B. pertussis cultures, previously fixed with glutaraldehyde, osmic acid and uranyl acetate, oval cells with the cytoplasm having a relatively homogeneous structure and with the smoothed-out three-layer cell wall prevail. As a rule, IC are limited to the sites of direct contacts between individual cells. 相似文献
9.
I N Blokhina V M Lavrovskaia R Sh Al'tman 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1978,(7):112-115
The authors prepared under experimental-industrial conditions paper indicator systems for the express identification of microbes, including carbohydrate discs (by the method of Nikitin et al.), and newly worked out types for the determination of the activity of cytochromoxidase, urease, indol formation, and indicator amino acid decarboxylases (lysin, ornithin, arginine). The use of paper indicator discs proved to be expedient for rationalization of laboratory diagnosis of bacterial intestinal infections. 相似文献
10.
Neurospecific and neuro-nonspecific isozymes of glycolytic enzyme enolase known to be molecular markers of neuronal and glial cells respectively were isolated from human brain. Using immunoenzyme assay, the content of these proteins was measured in the brain of 7-13-week human embryos and adult subjects. The content of both isoenzymes gradually increases attaining constant level in 10-13-week embryos. Relative content of neuro-nonspecific enolase in the brain of 10-13-week embryos is 1 1/2 times higher than that in adults, whereas the content of neurospecific enolase amounts only to 2% of its level in the adult brain. 相似文献