全文获取类型
收费全文 | 144423篇 |
免费 | 9186篇 |
国内免费 | 22篇 |
出版年
2023年 | 816篇 |
2022年 | 967篇 |
2021年 | 2243篇 |
2020年 | 1836篇 |
2019年 | 2114篇 |
2018年 | 3779篇 |
2017年 | 3402篇 |
2016年 | 4578篇 |
2015年 | 5975篇 |
2014年 | 6382篇 |
2013年 | 8476篇 |
2012年 | 9693篇 |
2011年 | 8886篇 |
2010年 | 5962篇 |
2009年 | 4883篇 |
2008年 | 7172篇 |
2007年 | 6810篇 |
2006年 | 6578篇 |
2005年 | 5624篇 |
2004年 | 5598篇 |
2003年 | 5083篇 |
2002年 | 4683篇 |
2001年 | 3589篇 |
2000年 | 3404篇 |
1999年 | 2771篇 |
1998年 | 1400篇 |
1997年 | 1045篇 |
1996年 | 1050篇 |
1995年 | 976篇 |
1994年 | 852篇 |
1993年 | 771篇 |
1992年 | 1584篇 |
1991年 | 1451篇 |
1990年 | 1376篇 |
1989年 | 1437篇 |
1988年 | 1218篇 |
1987年 | 1222篇 |
1986年 | 1121篇 |
1985年 | 1142篇 |
1984年 | 991篇 |
1983年 | 839篇 |
1982年 | 718篇 |
1979年 | 909篇 |
1978年 | 726篇 |
1975年 | 789篇 |
1974年 | 876篇 |
1973年 | 839篇 |
1972年 | 760篇 |
1969年 | 758篇 |
1968年 | 723篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Carmen de Sena-Tomás Mónica Navarro-González Ursula Kües José Pérez-Martín 《Genetics》2013,195(1):47-57
The fungal fruiting body or mushroom is a multicellular structure essential for sexual reproduction. It is composed of dikaryotic cells that contain one haploid nucleus from each mating partner sharing the same cytoplasm without undergoing nuclear fusion. In the mushroom, the pileus bears the hymenium, a layer of cells that includes the specialized basidia in which nuclear fusion, meiosis, and sporulation occur. Coprinopsis cinerea is a well-known model fungus used to study developmental processes associated with the formation of the fruiting body. Here we describe that knocking down the expression of Atr1 and Chk1, two kinases shown to be involved in the response to DNA damage in a number of eukaryotic organisms, dramatically impairs the ability to develop fruiting bodies in C. cinerea, as well as other developmental decisions such as sclerotia formation. These developmental defects correlated with the impairment in silenced strains to sustain an appropriated dikaryotic cell cycle. Dikaryotic cells in which chk1 or atr1 genes were silenced displayed a higher level of asynchronous mitosis and as a consequence aberrant cells carrying an unbalanced dose of nuclei. Since fruiting body initiation is dependent on the balanced mating-type regulator doses present in the dikaryon, we believe that the observed developmental defects were a consequence of the impaired cell cycle in the dikaryon. Our results suggest a connection between the DNA damage response cascade, cell cycle regulation, and developmental processes in this fungus. 相似文献
32.
33.
34.
V jarovisovaných a nejarovisovaných obilkách jedné ozimé a jedné jarní odr?dy p?enice byly chromatograficky stanoveny látky typu auxin? a giberelin?. Chromatogramy byly vyhodnoceny pomocí biologických test?. U ozimé odr?dy jsme nena?li rozdíly v rozlo?ení r?stových látek mezi jarovisovanou a nejarovisovanou variantou. U jarní odr?dy jsme rozdíly na?li. Na základě výsledk? soudíme, ?e rozdíly mezi oběma variantami jarní odr?dy byly zp?sobeny nespecifickým p?sobením nízké teploty a ?e proces jarovisace není kausálně spjat se změnami hladiny r?stových látek. 相似文献
35.
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
36.
37.
38.
Dr. Ed. Formánek 《Plant Systematics and Evolution》1888,38(12):419-423
Ohne Zusammenfassung 相似文献
39.
I Gut J Nerudová A Stiborová J Kopecky E Frantík 《Journal of hygiene, epidemiology, microbiology, and immunology》1985,29(1):9-13
In male Wistar rats, the inhalation exposure to acrylonitrile (AN), 271 mg X m-3, 8 hours a day, 5 days a week, did not affect protein sulfhydryl concentration in liver and blood and decreased glutathione concentration in the liver, but not in the brain at the end of the fifth exposure. The urinary excretion of the main AN metabolites, thioethers (AN-mercapturic acids) and thiocyanate was proportional to the inhaled AN concentration (57, 125, 271 mg X m-3, respectively) in a single exposure for 12 hours, and their mutual ratio was greatly different from that after injection of AN. The results revealed that the urinary excretion of thioethers is a very sensitive and dose-related indicator of exposure to AN and extrapolation of the results indicates that the exposure to AN concentration below 10 mg X m-3 could thus be demonstrated. 相似文献
40.