全文获取类型
收费全文 | 178056篇 |
免费 | 9229篇 |
国内免费 | 6581篇 |
出版年
2023年 | 1299篇 |
2022年 | 2934篇 |
2021年 | 5007篇 |
2020年 | 3282篇 |
2019年 | 4023篇 |
2018年 | 4763篇 |
2017年 | 3887篇 |
2016年 | 6773篇 |
2015年 | 11970篇 |
2014年 | 12490篇 |
2013年 | 12816篇 |
2012年 | 13321篇 |
2011年 | 9566篇 |
2010年 | 6748篇 |
2009年 | 6125篇 |
2008年 | 5375篇 |
2007年 | 4752篇 |
2006年 | 4302篇 |
2005年 | 9627篇 |
2004年 | 7765篇 |
2003年 | 5648篇 |
2002年 | 2956篇 |
2001年 | 2751篇 |
2000年 | 1872篇 |
1999年 | 2971篇 |
1998年 | 1214篇 |
1997年 | 1009篇 |
1996年 | 990篇 |
1995年 | 953篇 |
1994年 | 925篇 |
1992年 | 2687篇 |
1991年 | 2613篇 |
1990年 | 2635篇 |
1989年 | 2387篇 |
1988年 | 2271篇 |
1987年 | 2112篇 |
1986年 | 1837篇 |
1985年 | 1906篇 |
1984年 | 1243篇 |
1983年 | 986篇 |
1979年 | 1159篇 |
1978年 | 801篇 |
1975年 | 911篇 |
1974年 | 1044篇 |
1973年 | 1056篇 |
1972年 | 992篇 |
1971年 | 960篇 |
1970年 | 841篇 |
1969年 | 860篇 |
1967年 | 769篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
I P Grigor'ev A A Neokesari?ski? 《Biulleten' eksperimental'no? biologii i meditsiny》1986,102(9):288-289
The effects of different concentrations of L-ascorbic acid (Asc) on Na+-dependent binding of 3H-GABA and 3H-DL-glutamic acid to rat brain cortical synaptosomes were studied. Asc, at a concentration nearly equal to brain extracellular one (3 X 10(-4) M), had no effect on specific and nonspecific 5H-GABA binding. At higher concentrations (10(-3) M) Asc strongly inhibited, and at lower concentrations (10(-6) M) considerably stimulated 3H-GABA binding. At a concentration of 10(-5)-10(-3) M Asc tended to decrease 3H-DL-glutamic acid binding. 相似文献
52.
D G Astaf'ev I V Maianskaia A K Akatov A N Maianski? 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1986,(7):48-51
In investigations based on the use of a highly sensitive test system permitting the detection of normal human antibodies to S. aureus peptidoglycan, the antigenic relationships between the peptidoglycans of S. aureus and other representatives of the genus Staphylococcus have been studied. Among other staphylococcal species, S. simulans, S. xylosus, S. hyicus, S. cohnii, S. hyicus s. s. chromogenes have been found to possess peptidoglycans most closely related to S. aureus peptidoglycans, while S. warneri and S. epidermidis peptidoglycans have proved to be least closely related to it. 相似文献
53.
ESR spectra of gamma-irradiated and frozen at 77 K human oxyhemoglobin and partially denaturated methemoglobin solutions were analysed. The quartet signal ascribed to the anion-radical of proximal histidine was shown to dominate in the spectra of both solutions. The spectra of methemoglobin solution irradiated with relatively small doses have an intensive singlet ascribed to the stabilized electron. The formation mechanism of free radicals is discussed. 相似文献
54.
Interaction between cytotoxin of the Central Asia cobra venom and dimiristoylphosphatidylcholine bilayer depending on its phase state was studied by ESR with spin label. A conclusion can be drawn that the efficiency of cytotoxin effect on the membranes depends on their phase state. Cytotoxin molecules are incorporated into myophile region of the bilayer, only if the latter is in the liquid crystal state. The interaction between cytotoxins and lipids of the bilayer in a gel state is in the main conditioned by electrostatic forces. 相似文献
55.
56.
57.
58.
Indomethacin and substance BW-755C in experiments on isolated myometrium striae of pregnant white rats exert an inhibiting effect on the contractile uterus function due to inhibition of cyclooxygenase or lipoxygenase ways of the arachidonic acid transformation. Prostaglandin F2 alpha is sensitive to functioning of the cyclooxygenase and lipoxygenase ways of the arachidonic acid transformation, while oxytocin--only lipoxygenase one. Conclusions rest on results from multiparametric analysis of the contractile uterus function suggested by authors and confirmed by the pattern recognition method--the Karunen-Loev orthogonal decomposition. 相似文献
59.
Rebecca R. Sharitz Susan A. Wineriter Michael H. Smith Edwin H. Liu 《American journal of botany》1980,67(9):1297-1303
Biochemical phenotsypes of four taxa of Typha from the eastern United States were determined by starch gel electrophoresis. The isozyme banding patterns of T. latifolia, T. angustifolia and T. domingensis are distinct and allow unambiguous species identification when morphological characters are inadequate or unsuitable. The fourth form, T. glauca, is not an F1 hybrid, but it does appear to be intermediate between T. latifolia and T. angustifolia. The status of T. glauca and evolutionary relationships among the four forms may now be clarified by additional sampling because of the distinct and relatively invariant isozyme banding patterns which are described. 相似文献
60.