全文获取类型
收费全文 | 496篇 |
免费 | 153篇 |
专业分类
649篇 |
出版年
2022年 | 3篇 |
2021年 | 3篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 16篇 |
2014年 | 16篇 |
2013年 | 18篇 |
2012年 | 26篇 |
2011年 | 11篇 |
2010年 | 8篇 |
2009年 | 10篇 |
2008年 | 14篇 |
2007年 | 19篇 |
2006年 | 23篇 |
2005年 | 9篇 |
2004年 | 32篇 |
2003年 | 78篇 |
2002年 | 93篇 |
2001年 | 62篇 |
2000年 | 36篇 |
1999年 | 25篇 |
1998年 | 9篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 8篇 |
1976年 | 3篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 4篇 |
1967年 | 2篇 |
排序方式: 共有649条查询结果,搜索用时 15 毫秒
1.
The spontaneous allele quakingviable (qk
v
) exerts effects on myelination and spermiogenesis. The defects generated by qk
v
were not separated in a multilocus mapping cross that provided a mapping resolution of 0.1 centiMorgans (cM). Furthermore, no distortions suggestive of a large chromosomal anomaly associated with qk
v
were apparent. One plausible interpretation is that the quaking locus contains more than one functional domain, either organized into overlapping genes or expressed by alternative splicing mechanisms. The cloning needed to analyze this locus will be enhanced by the very high resolution of the meiotic mapping cross reported here. The recombinational distances on this qk
v
map were compressed compared with those previously reported in a high-resolution map for qk
1–1, an embryonic lethal allele of quaking induced by ethylnitrosourea. Additional crosses confirmed prior reports that the sex and the genetic background of the heterozygous parent can affect recombinational distances. These joint effects on recombination are strong enough to account for the discrepancy between the two maps. This variability of two-factor map values leads to the preferred multilocus map-building protocol discussed in the accompanying paper. 相似文献
2.
3.
4.
Evidence is presented of the ability of H-2 class I antigens to function as teratocarcinoma transplantation (Gt) antigens. Coisogenic immunization against H-2 class I antigens expressed on transfected L cells is shown to induce resistance to embryonic carcinoma (EC) cell allografts. The Kb, Db, Dd, and, in appropriate recipients, Ld antigens can function as Gt antigens. The protocol presented may be useful for the molecular identification of other genes encoding histocompatibility antigens. 相似文献
5.
A clone coding for Schizophyllum commune beta-glucosidase: homology with a yeast beta-glucosidase 总被引:3,自引:0,他引:3
F Moranelli J R Barbier M J Dove R M MacKay V L Seligy M Yaguchi G E Willick 《Biochemistry international》1986,12(6):905-912
Three identical clones coding for a partial sequence of the Schizophyllum commune beta-glucosidase were isolated from a cDNA library in lambda gt11, using polyclonal antibody to the enzyme. The identity was confirmed by comparison of the amino-terminus of a peptide from a protease lys-C digest with the sequence inferred from the cDNA sequence. A comparison of the sequence with that reported for a beta-glucosidase from Candida pelliculosa revealed a region in the latter with 43% identity in amino acid sequence. There was also a similarity in the S. commune beta-glucosidase to an active site sequence proposed for a S. commune endoglucanase, suggesting the possibility of a common catalytic mechanism for these two glucolytic enzymes. 相似文献
6.
Hardies SC; Martin SL; Voliva CF; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1986,3(2):109-125
7.
8.
S. Dove J. Horwitz M. McFall-Ngai 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1993,172(5):565-572
The present study is a biochemical characterization of the photophore lenses of the midshipman fish, Porichthys notatus, a species that bears 800 photophores distributed over the body surface. The biochemical properties of the photophore lenses were compared with those of the eye lens with which they share a similar developmental origin and analogous function. To achieve a high refractive index, the vertebrate eye lens has a relatively high concentration of structural proteins (20–50%, depending on species) and a simple protein composition, that is, relatively few proteins are synthesized in comparison to other tissues. Similarly, the photophore lenses of P. notatus had a relatively high protein concentration (average = 29%, n = 5) and approximately 60% of the total soluble protein was represented by two subunit species of 33 kD and 35 kD on denaturing polyacrylamide gels. The structural proteins of the eye lens are of two principle types: 1) and polypeptides which belong to vertebrate lens-specific crystallin families, and, 2) enzymes recruited into the lens which take on the function of structural proteins. Here, we report that the two major photophore lens subunits of 33 kD and 35 kD are biochemically similar to each other, but are clearly distinct from any of the previously characterized crystallins. Therefore, we propose that photophore lenses appear to recruit a novel protein. 相似文献
9.
10.
Seligy VL Barbier JR Dimock KD Dove MJ Moranelli F Morosoli R Willick GE Yaguchi M 《Biotechnology advances》1984,2(2):201-216
New gene selection techniques (Recombinant DNA) are currently available to exploit useful properties of various biological systems hitherto regarded as interesting but of little or no immediate commercial value. The application of genetic engineering techniques to problems in the Pulp and Paper Industry are many. As a first step these techniques are being used to provide much needed fundamental information on the cellular and molecular mechanisms involved in the expression of extra-cellular enzymes that degrade lignocellulosic pulping wastes. The information gleaned from the studies on cellulolytic fungi and bacteria can be used to genetically engineer a yeast or bacterium capable of converting pulping wastes into ethanol and other useful by-products. 相似文献