全文获取类型
收费全文 | 329篇 |
免费 | 32篇 |
专业分类
361篇 |
出版年
2023年 | 3篇 |
2015年 | 7篇 |
2014年 | 4篇 |
2013年 | 11篇 |
2012年 | 8篇 |
2011年 | 15篇 |
2010年 | 7篇 |
2009年 | 9篇 |
2008年 | 4篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 9篇 |
2004年 | 19篇 |
2003年 | 11篇 |
2002年 | 11篇 |
2001年 | 10篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 10篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1989年 | 10篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1982年 | 5篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1975年 | 11篇 |
1974年 | 10篇 |
1973年 | 5篇 |
1972年 | 7篇 |
1971年 | 7篇 |
1970年 | 5篇 |
1966年 | 4篇 |
1965年 | 4篇 |
1961年 | 2篇 |
1959年 | 2篇 |
1928年 | 2篇 |
1908年 | 2篇 |
排序方式: 共有361条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
Purification of hemoglobin from North Atlantic salmon (Salmo salar) gave three different types. The CO-complexes of types I and III have been crystallized by the batch method at 4 degrees C from solutions 18% (w/v) in polyethylene glycol 2000, 50 mg/ml in hemoglobin and 0.05 M in phosphate buffer (pH 8.3). Orthorhombic crystals, space group P2(1)2(1)2(1), were obtained for both, with cell dimensions a = 53.9 A, b = 80.4 A, c = 132.4 A, and a = 58.7 A, b = 95.0 A, c = 107.4 A, for types I and III, respectively. 相似文献
95.
96.
97.
Rabbit antibodies have been raised to pig heart citrate synthase. Using purified IgG, competitive enzyme-linked immunoassays and assays of citrate synthase activity indicate the presence of antibodies to a number of antigenic sites on the enzyme, only some of which are essential for catalytic activity. From a comparison of citrate synthases from prokaryotic and eukaryotic organisms, the degree of interaction between antibody and enzyme was in the order: pig heart greater than pigeon breast greater than Bacillus megaterium greater than Escherichia coli. These findings are discussed in terms of the known interspecies diversity of the enzyme. 相似文献
98.
Leah C. Solberg William Valdar Dominique Gauguier Graciela Nunez Amy Taylor Stephanie Burnett Carmen Arboledas-Hita Polinka Hernandez-Pliego Stuart Davidson Peter Burns Shoumo Bhattacharya Tertius Hough Douglas Higgs Paul Klenerman William O. Cookson Youming Zhang Robert M. Deacon J. Nicholas P. Rawlins Richard Mott Jonathan Flint 《Mammalian genome》2006,17(2):129-146
Whole-genome genetic association studies in outbred mouse populations represent a novel approach to identifying the molecular
basis of naturally occurring genetic variants, the major source of quantitative variation between inbred strains of mice.
Measuring multiple phenotypes in parallel on each mouse would make the approach cost effective, but protocols for phenotyping
on a large enough scale have not been developed. In this article we describe the development and deployment of a protocol
to collect measures on three models of human disease (anxiety, type II diabetes, and asthma) as well as measures of mouse
blood biochemistry, immunology, and hematology. We report that the protocol delivers highly significant differences among
the eight inbred strains (A/J, AKR/J, BALBc/J, CBA/J, C3H/HeJ, C57BL/6 J, DBA/2 J, and LP/J), the progenitors of a genetically
heterogeneous stock (HS) of mice. We report the successful collection of multiple phenotypes from 2000 outbred HS animals.
The phenotypes measured in the protocol form the basis of a large-scale investigation into the genetic basis of complex traits
in mice designed to examine interactions between genes and between genes and environment, as well as the main effects of genetic
variants on phenotypes. 相似文献
99.
In a chain of lakes along which nutrient availability varies in a gradient, we performed factorial nutrient enrichment experiments
to determine if nitrogen limitation was the principal factor controlling the differences in phytoplankton biomass, photosynthetic
productivity, diversity, and species composition among two of the lakes in the chain. In the least productive lake, East Graham
Lake, P and C enrichments (in the absence of N enrichment) had no effect on biomass and diversity, whereas within two weeks
the N enrichments (alone or in any combination with P and/or C) increased the biomass and decreased the diversity of East
Graham Lake phytoplankton to levels similar or identical to those in more productive Shoe Lake. Short-term 14C photosynthetic rates in East Graham Lake water also responded only to N in the third week. However, photosynthesis was stimulated
by P in the first week, and a few species did increase in numbers with P enrichment, suggesting that some degree of P limitation
remains in addition to the strong N limitation in East Graham Lake. A number of species responded individually to the enrichments
in a manner similar to that of the overall community, and a strong overlapping of discriminant analysis scores for N-enriched
East Graham Lake with those of Shoe Lake was consistent with our prediction that the community structure of N-enriched East
Graham Lake water would shift toward that of Shoe Lake. However, many species did not respond consistently with these results,
and the nutrients tested were clearly not a major factor in the differences in abundance of those species among the two lakes.
The results support the argument that overall biomass production and diversity of the phytoplankton community in a lake can
be a relatively simple function of a single most-limiting nutrient. However, many of the species responses also confirm that,
while nutrient availability is an important factor in the control of the species composition of the community, other factors
are likely to prevent reliable predictions of all species effects on the basis of nutrient availability alone. 相似文献
100.