全文获取类型
收费全文 | 990篇 |
免费 | 72篇 |
出版年
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 10篇 |
2019年 | 16篇 |
2018年 | 19篇 |
2017年 | 11篇 |
2016年 | 25篇 |
2015年 | 23篇 |
2014年 | 38篇 |
2013年 | 50篇 |
2012年 | 85篇 |
2011年 | 121篇 |
2010年 | 99篇 |
2009年 | 67篇 |
2008年 | 63篇 |
2007年 | 60篇 |
2006年 | 56篇 |
2005年 | 65篇 |
2004年 | 53篇 |
2003年 | 31篇 |
2002年 | 31篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 11篇 |
1998年 | 5篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1993年 | 2篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1985年 | 5篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 6篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1969年 | 2篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1965年 | 3篇 |
1962年 | 1篇 |
排序方式: 共有1062条查询结果,搜索用时 15 毫秒
1.
2.
T A Deviatkina V V Brechko L M Tarasenko I N Zviago'lskaia Iu V Bezugly? I R Rituma V E Klusha 《Fiziologicheski? zhurnal》1989,35(5):14-18
Experiments on rats subjected to acute stress have revealed protective effect of thymopentin pentapeptide on somatic disorders and the state of the antioxidation system and the processes of lipid peroxidation in blood and brain. 相似文献
3.
Common antigens of mouse oval and biliary epithelial cells. Expression on newly formed hepatocytes 总被引:17,自引:0,他引:17
Natalya V. Engelhardt Valentina M. Factor Alla K. Yasova Valentina S. Poltoranina Vladimir N. Baranov Maria N. Lasareva 《Differentiation; research in biological diversity》1990,45(1):29-37
Two antigens - A6 and G7 - shared by mouse biliary epithelial and oval cells were revealed by monoclonal antibodies raised in rat immunized with oval-cell-enriched liver fraction. Oval cells were induced in CBA or F1 (CBA x C57BL6) mice by a combination of a single injection of the alkylating drug Dipin with partial hepatectomy. In normal liver A6 antigen was localized, using light and electron microscopy, in biliary epithelial cells of all ducts including Hering canals. Some bile ductal and Hering cells were A6-negative. Occasionally, A6 antigen was present in single hepatocytes forming the periportal ends of hepatic cords. In preneoplastic and tumorous liver A6 antigen was present in bile ductal and oval cells and in a fraction of newly formed hepatocytes and tumor cells. G7 antigen was revealed in normal, precancerous and tumorous liver in biliary epithelial and oval cells but not in hepatocytes. A6 and G7 antigens were not liver-specific: they were expressed in various normal organs and tissues, especially in epithelia. In studies of mouse liver lineages A6 antigen can be used as a common marker of biliary epithelial and oval cells and hepatocytes at certain stages of differentiation. G7 antigen is a marker of oval and biliary epithelial cells. There was a striking similarity in A6 antigen localization to that of human blood group antigens in normal liver and liver tumors. A6 antigen may thus provide a useful tool for the study of neoexpression of human blood group antigens in liver tumors. 相似文献
4.
L M Tarasenko T A Petryshanko V F Grebennikova I N Skrypnik 《Fiziologicheski? zhurnal》1991,37(6):88-91
Using the model of immobilizing stress in rats, it has been established that the content of sialic acids in the stomach mucous membrane (SMM) and blood serum rises with simultaneous activation of proteolytic enzymes in them. The preliminary adaptation to short stressor influences parallel with an antipathogenic effect normalizes the content of sialic acids in the blood serum and SMM. The conclusion is made on the essential role of the degradation of gastric mucus in pathogenesis of stress ulcers. 相似文献
5.
Unsaturated fatty acids at concentrations of 1–2 μmol mg-1 chlorophyll decrease the intensity of long-lived delayed fluorescence and inhibit the Hill reaction in Pisum sativum L. chloroplasts in a pH-dependent and reversible manner. A charged form of the fatty acids is two times more effective than an undissociated form. Fatty acids, anionic and cationic detergents and urea inhibit activity and decrease the temperature of heat inactivation of the water-spilitting system. Sucrose at a concentration of 2.5 M protects chloroplasts against the effects of these compounds. It is concluded that their action can be explained by the denaturation of the water-splitting protein. 相似文献
6.
7.
Cold acclimation and photoinhibition of photosynthesis in Scots pine 总被引:13,自引:0,他引:13
Alla Krivosheeva Da-Li Tao Christina Ottander Gunnar Wingsle Sylvain L. Dube Gunnar Öquist 《Planta》1996,200(3):296-305
Cold acclimation of Scots pine did not affect the susceptibility of photosynthesis to photoinhibition. Cold acclimation did however cause a suppression of the rate of CO2 uptake, and at given light and temperature conditions a larger fraction of the photosystem II reaction centres were closed in cold-acclimated than in nonacclimated pine. Therefore, when assayed at the level of photosystem II reaction centres, i.e. in relation to the degree of photosystem closure, cold acclimation caused a significant increase in resistance to photoinhibition; at given levels of photosystem II closure the resistance to photoinhibition was higher after cold acclimation. This was particularly evident in measurements at 20° C. The amounts and activities of the majority of analyzed active oxygen scavengers were higher after cold acclimation. We suggest that this increase in protective enzymes and compounds, particularly Superoxide dismutase, ascorbate peroxidase, glutathione reductase and ascorbate of the chloroplasts, enables Scots pine to avoid excessive photoinhibition of photosynthesis despite partial suppression of photosynthesis upon cold acclimation. An increased capacity for light-induced de-epoxidation of violaxanthin to zeaxanthin upon cold acclimation may also be of significance.Abbreviations APX
ascorbate peroxidase
- DHA
dehydroascorbate
- DHAR
dehydroascorbate reductase
- Fm
maximal fluorescence when all reaction centres are closed
- Fv/Fm
maximum photochemical yield of PSII
- GR
glutathione reductase
- GSH
reduced glutathione
- Je
rate of photosynthetic electron transport
- MDAR
monodehydroascorbate reductase
- qN
nonphotochemical quenching of fluorescence
- qP
photochemical quenching of fluorescence
- SOD
superoxide dismutase
This work was supported by the Swedish Natural Science Research Council and the National Natural Science Foundation of China. 相似文献
8.
Dr. Georgy M. Gongadze Alla S. Kostyukova Margarita L. Miroshnichenko Elizaveta A. Bonch-Osmolovskaya 《Current microbiology》1993,27(1):5-9
Proteinaceous layers of theThermococcus stetteri cell envelope were investigated and found to consist of regularly arrayed subunits 18 nm in diameter. According to the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, two major proteins were present. They were glycosylated and had molecular weights of 80,000 and 210,000. In addition to two external regular proteinaceous layers, cells ofT. stetteri were found to have internal regular layers tightly attached to the cytoplasmic membrane. In the region of flagella attachment to the cell, polar membrane-like structures were found in the cytoplasm. 相似文献
9.
L M Tarasenko V F Grebennikova T A Deviatkina T A Petrushanko O I Tsebrzhinski? 《Fiziologicheski? zhurnal》1989,35(5):78-81
Experiments on 39 rats subjected to the effect of acute, chronic stresses and to that of their combination have revealed a parallelism between the degree of the ulcerogenic effect and depression of antioxidant activity of the stomach tissue cells. 相似文献
10.
Plasma Physics Reports - Consideration is given to the formation of conditions and parameters of diffuse and volume discharges, which are widely used for laser generation in VUV, UV, visible and IR... 相似文献