全文获取类型
收费全文 | 425篇 |
免费 | 50篇 |
专业分类
475篇 |
出版年
2022年 | 5篇 |
2021年 | 16篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 16篇 |
2014年 | 13篇 |
2013年 | 19篇 |
2012年 | 25篇 |
2011年 | 20篇 |
2010年 | 11篇 |
2009年 | 13篇 |
2008年 | 16篇 |
2007年 | 11篇 |
2006年 | 11篇 |
2005年 | 17篇 |
2004年 | 15篇 |
2003年 | 13篇 |
2002年 | 15篇 |
2001年 | 17篇 |
2000年 | 16篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1993年 | 3篇 |
1992年 | 8篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1970年 | 3篇 |
1969年 | 7篇 |
1968年 | 3篇 |
1942年 | 3篇 |
1941年 | 6篇 |
1940年 | 6篇 |
1939年 | 7篇 |
1938年 | 3篇 |
排序方式: 共有475条查询结果,搜索用时 15 毫秒
101.
102.
Tissue cultures of the halophytic saltmarsh grass Sporobolus virginicus were initiated from unemerged immature inflorescence tissue. Typical graminaceous embryogenic and nonembryogenic callus and cell types were noted. Embryogenic callus was compact golden yellow. Histological evidence indicated that proliferation of the ovary tissue of the immature pistil was the source for embryogenic callus. Plants regenerated after first reducing and then eliminating auxin from the culture medium. Regeneration was observed both through the concerted development of bipolar meristems from somatic embryos and by the formation of multiple shoot meristems that were either connected through callus tissue to root meristems or which later adventitiously rooted. The main mode of regeneration appeared to be somatic embryogenesis with additional multiple shoot formation probably due to precocious germination of somatic embryos. Plants recovered from culture were acclimated to soil, grown up in a greenhouse, and planted in field plots with saline irrigation to ensure stability of salt tolerance. 相似文献
103.
104.
Freisleben Weickmann Ernst Eckhard Kuhn F. Resende Straub Schmidt E. Stein J. Straub Heberer H. Ernst Hilde Pieper W. J. Schmidt J. Kisser H. -J. Troll R. Schick Eifrig Aust Schröck Stelzner Schröck Schieblich R. Schick Schwanitz Hilde Pieper Gruber Lang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1941,13(4):88-96
Ohne Zusammenfassung 相似文献
105.
Breider Propach R. W. Böhme Hoffmann Stelzner Sessous Lang K. L. Noack Fischer J. Straub 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1940,12(6):153-160
Ohne Zusammenfassung 相似文献
106.
Investigations were carried out to determine levels of biogenic monoamines in the central nervous tissue of seven species of terrestrial gastropods (taxonomic family: Helicidae) using high-performance liquid chromatography (HPLC) with electrochemical detection (ELCD). The central nervous tissue of all species examined contained assayable amounts of dopamine (DA) and serotonin (5-HT). Noradrenaline (NA) was occasionally present; adrenaline (A) could not be detected. The central ganglia of two Mediterranean species generally contain 3-4 times more 5-HT relative to DA than the ganglia of the other species which contain amounts of 5-HT only slightly higher than DA. 相似文献
107.
108.
K. Esser und J. Straub 《Molecular & general genetics : MGG》1958,89(5):729-746
Ohne ZusammenfassungMit 6 Textabbildungen, davon1 farbigeMit Unterstützung der Deutschen Forschungsgemeinschaft und des Ministeriums für Wirtschaft und Verkehr NRW. 相似文献
109.
Protein aggregation, linked to many of diseases, is initiated when monomers access rogue conformations that are poised to form amyloid fibrils. We show, using simulations of src SH3 domain, that mechanical force enhances the population of the aggregation-prone (N?) states, which are rarely populated under force free native conditions but are encoded in the spectrum of native fluctuations. The folding phase diagrams of SH3 as a function of denaturant concentration ([C]), mechanical force (f), and temperature exhibit an apparent two-state behavior, without revealing the presence of the elusive N? states. Interestingly, the phase boundaries separating the folded and unfolded states at all [C] and f fall on a master curve, which can be quantitatively described using an analogy to superconductors in a magnetic field. The free energy profiles as a function of the molecular extension (R), which are accessible in pulling experiments, (R), reveal the presence of a native-like N? with a disordered solvent-exposed amino-terminal β-strand. The structure of the N? state is identical with that found in Fyn SH3 by NMR dispersion experiments. We show that the timescale for fibril formation can be estimated from the population of the N? state, determined by the free energy gap separating the native structure and the N? state, a finding that can be used to assess fibril forming tendencies of proteins. The structures of the N? state are used to show that oligomer formation and likely route to fibrils occur by a domain-swap mechanism in SH3 domain. 相似文献