全文获取类型
收费全文 | 137061篇 |
免费 | 6369篇 |
国内免费 | 4100篇 |
出版年
2023年 | 595篇 |
2022年 | 1044篇 |
2021年 | 2563篇 |
2020年 | 1820篇 |
2019年 | 2246篇 |
2018年 | 3212篇 |
2017年 | 2937篇 |
2016年 | 5234篇 |
2015年 | 9037篇 |
2014年 | 9389篇 |
2013年 | 9428篇 |
2012年 | 9192篇 |
2011年 | 6237篇 |
2010年 | 5024篇 |
2009年 | 4615篇 |
2008年 | 3580篇 |
2007年 | 3175篇 |
2006年 | 2893篇 |
2005年 | 8557篇 |
2004年 | 7115篇 |
2003年 | 5233篇 |
2002年 | 2528篇 |
2001年 | 2124篇 |
2000年 | 1197篇 |
1999年 | 2115篇 |
1998年 | 763篇 |
1992年 | 2235篇 |
1991年 | 2288篇 |
1990年 | 2299篇 |
1989年 | 2213篇 |
1988年 | 2096篇 |
1987年 | 2000篇 |
1986年 | 1783篇 |
1985年 | 1806篇 |
1984年 | 1203篇 |
1983年 | 944篇 |
1979年 | 1149篇 |
1978年 | 841篇 |
1977年 | 667篇 |
1976年 | 699篇 |
1975年 | 932篇 |
1974年 | 1056篇 |
1973年 | 1076篇 |
1972年 | 1013篇 |
1971年 | 969篇 |
1970年 | 858篇 |
1969年 | 861篇 |
1968年 | 745篇 |
1967年 | 759篇 |
1966年 | 595篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
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
62.
63.
S. T. Zakhidov T. L. Marshak E. A. Malolina A. Yu. Kulibin I.A. Zelenina S. M. Pavluchenkova V. M. Rudoi O. V. Dement’eva S. G. Skuridin Yu. M. Evdokimov 《Biochemistry (Moscow) Supplemental Series A: Membrane and Cell Biology》2010,4(3):293-296
The effect of gold nanoparticles on mouse epididymal sperm has been studied using the model system of nuclear chromatin decondensation
in vitro. It is shown that the treatment of gametes, preliminary membrane-freed by sodium dodecyl sulfate, in the mediums
containing gold nanoparticles (with diameter ∼2.5 nm) in concentrations 1.0 × 1015 or 0.5 × 1015 particles/ml and following incubation in dithiothreitol solution (DTT) resulted in failure of chromatin decondensation process
and nucleus structure. We conclude that gold nanoparticles possess spermatotoxicity. The mechanism of cytotoxic effect of
gold nanoparticles may be related with their interaction with molecules of double-helix DNA. The model system studied in this
research is applicable for further investigations of cytotoxic effects of nanoparticles of different origin and made of different
metals. 相似文献
64.
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
65.
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
66.
67.
Mirror carp were infected with Ichthyophthirius multifiliis (Fouquet) under standardized conditions. The size and number of parasites at selected sites on the body were recorded during the course of the infection. Initial exposure to 40 mature parasites resulted in a mild infection with 100% recovery after 18 days. Recovered fish did not appear to be carriers of the parasite. Exposure to 400 parasites resulted in 100% mortality between 22–25 days. The growth rate of the parasite was linear. Parasites were more numerous in the dorsal surface of the fish than in the lateral or ventral surface. The increase in parasite numbers during the disease was greater in the gills than in the skin. 相似文献
68.
69.
70.
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