全文获取类型
收费全文 | 479篇 |
免费 | 12篇 |
专业分类
491篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2019年 | 9篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 15篇 |
2015年 | 13篇 |
2014年 | 30篇 |
2013年 | 27篇 |
2012年 | 40篇 |
2011年 | 60篇 |
2010年 | 32篇 |
2009年 | 14篇 |
2008年 | 32篇 |
2007年 | 26篇 |
2006年 | 23篇 |
2005年 | 24篇 |
2004年 | 28篇 |
2003年 | 26篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1969年 | 2篇 |
排序方式: 共有491条查询结果,搜索用时 0 毫秒
31.
32.
Kim MH Cierpicki T Derewenda U Krowarsch D Feng Y Devedjiev Y Dauter Z Walsh CA Otlewski J Bushweller JH Derewenda ZS 《Nature structural biology》2003,10(5):324-333
The doublecortin-like domains (DCX), which typically occur in tandem, are novel microtubule-binding modules. DCX tandems are found in doublecortin, a 360-residue protein expressed in migrating neurons; the doublecortin-like kinase (DCLK); the product of the RP1 gene that is responsible for a form of inherited blindness; and several other proteins. Mutations in the gene encoding doublecortin cause lissencephaly in males and the 'double-cortex syndrome' in females. We here report a solution structure of the N-terminal DCX domain of human doublecortin and a 1.5 A resolution crystal structure of the equivalent domain from human DCLK. Both show a stable, ubiquitin-like tertiary fold with distinct structural similarities to GTPase-binding domains. We also show that the C-terminal DCX domains of both proteins are only partially folded. In functional assays, the N-terminal DCX domain of doublecortin binds only to assembled microtubules, whereas the C-terminal domain binds to both microtubules and unpolymerized tubulin. 相似文献
33.
The study presents an analysis of the restriction pattern ofrDNA fragments of 95 C. albicans isolates previously classified on the basis of the presence of the intron in rDNA into genotypes A (62 isolates), B (28), and C (5). Most isolates (61) with genotype A were classified as "subtype a" and one as "subtype d" (Karahan and Akar; 2005). No differences were observed in the restriction patterns of the tested genotype B isolates. Similarly, most genotype C strains (4/5) showed the same restriction pattern. The results indicate low subtyping variations of the analyzed isolates, which is in contrast to published data obtained from a Turkish collection of yeasts. 相似文献
34.
A viable wheat hybrid intermediate of the same height as the parents was obtained by crossing the female parent of tall variety NP4 with the male parent of the dwarf variety HD2160. Seeds of the hybrid and its parents were germinated and their growth pattern as well as the activities of peroxidase, indolyl-3-acetic acid oxidase and amylase in extracts made from them were studied at the early seedling stages i.e. up to 96 h.
A positive correlation existed between the length of the axis at the early seedling stage and at mature plant height as far as the parental varieties are concerned but no such correlation was observed with the hybrid. Growth of the hybrid seedlings was less than of its parents. Light appeared to stimulate the longitudinal growth of the axis to different extents in the parents and hybrid. Higher activities of peroxidase, indolyl-3-acetic acid oxidase and amylase were observed in the hybrid as compared to both of its parents. Lethal wheat hybrid also exhibits increased activities of amylase, indolyl-3-acetic acid oxidase and peroxidase. Therefore, it appears that seedling growth and enzyme activities at the seedling stage are not always correlated with hybrid vigour. 相似文献
A positive correlation existed between the length of the axis at the early seedling stage and at mature plant height as far as the parental varieties are concerned but no such correlation was observed with the hybrid. Growth of the hybrid seedlings was less than of its parents. Light appeared to stimulate the longitudinal growth of the axis to different extents in the parents and hybrid. Higher activities of peroxidase, indolyl-3-acetic acid oxidase and amylase were observed in the hybrid as compared to both of its parents. Lethal wheat hybrid also exhibits increased activities of amylase, indolyl-3-acetic acid oxidase and peroxidase. Therefore, it appears that seedling growth and enzyme activities at the seedling stage are not always correlated with hybrid vigour. 相似文献
35.
Breaking the apple embryo dormancy by nitric oxide involves the stimulation of ethylene production 总被引:4,自引:0,他引:4
Mature seeds of apple (Mallus domestica Borb. cv. Antonówka) are dormant and do not germinate unless their dormancy is removed by several weeks of moist-cold treatment.
We investigated the effect of short-term (3 h) nitric oxide (NO) pretreatment on breaking of apple embryonic dormancy expressed
as inhibition of germination and morphological abnormalities of young seedlings. Imbibition of embryos isolated from dormant
apple seeds with sodium nitroprusside (SNP) or S-nitroso,N-acetyl penicillamine (SNAP) as NO donors resulted in enhanced germination. Moreover, NO treatment removed morphological abnormalities
of seedlings developing from dormant embryo. The NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-teramethylimidazoline-1-oxyl-3 oxide
(cPTIO) removed the above effects. NO-mediated breaking of embryonic dormancy correlated well with enhanced ethylene production.
Inhibitor of ethylene synthesis (AOA) reversed the stimulatory effect of NO donors on embryo germination. Additionally SNP
reduced embryo sensitivity to exogenously applied ABA ensuing dormancy breakage. We can conclude that NO acts as a regulatory
factor included in the control of apple embryonic dormancy breakage by stimulation of ethylene biosynthesis. 相似文献
36.
The structure of the coiled-coil domain of Ndel1 and the basis of its interaction with Lis1, the causal protein of Miller-Dieker lissencephaly 总被引:2,自引:0,他引:2
Derewenda U Tarricone C Choi WC Cooper DR Lukasik S Perrina F Tripathy A Kim MH Cafiso DS Musacchio A Derewenda ZS 《Structure (London, England : 1993)》2007,15(11):1467-1481
Ndel1 and Nde1 are homologous and evolutionarily conserved proteins, with critical roles in cell division, neuronal migration, and other physiological phenomena. These functions are dependent on their interactions with the retrograde microtubule motor dynein and with its regulator Lis1--a product of the causal gene for isolated lissencephaly sequence (ILS) and Miller-Dieker lissencephaly. The molecular basis of the interactions of Ndel1 and Nde1 with Lis1 is not known. Here, we present a crystallographic study of two fragments of the coiled-coil domain of Ndel1, one of which reveals contiguous high-quality electron density for residues 10-166, the longest such structure reported by X-ray diffraction at high resolution. Together with complementary solution studies, our structures reveal how the Ndel1 coiled coil forms a stable parallel homodimer and suggest mechanisms by which the Lis1-interacting domain can be regulated to maintain a conformation in which two supercoiled alpha helices cooperatively bind to a Lis1 homodimer. 相似文献
37.
38.
Biogeochemistry - Salinization of freshwater ecosystems impacts carbon cycling, a particular concern for coastal wetlands, which are important agents of carbon sequestration. Previous experimental... 相似文献
39.
40.