全文获取类型
收费全文 | 2873篇 |
免费 | 247篇 |
国内免费 | 1篇 |
出版年
2023年 | 19篇 |
2022年 | 12篇 |
2021年 | 72篇 |
2020年 | 60篇 |
2019年 | 51篇 |
2018年 | 87篇 |
2017年 | 64篇 |
2016年 | 140篇 |
2015年 | 160篇 |
2014年 | 169篇 |
2013年 | 221篇 |
2012年 | 246篇 |
2011年 | 226篇 |
2010年 | 142篇 |
2009年 | 110篇 |
2008年 | 172篇 |
2007年 | 169篇 |
2006年 | 128篇 |
2005年 | 133篇 |
2004年 | 111篇 |
2003年 | 106篇 |
2002年 | 81篇 |
2001年 | 20篇 |
2000年 | 14篇 |
1999年 | 22篇 |
1998年 | 18篇 |
1997年 | 14篇 |
1996年 | 15篇 |
1995年 | 15篇 |
1994年 | 11篇 |
1993年 | 14篇 |
1992年 | 23篇 |
1991年 | 13篇 |
1990年 | 14篇 |
1989年 | 15篇 |
1988年 | 13篇 |
1987年 | 9篇 |
1986年 | 17篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1979年 | 14篇 |
1977年 | 10篇 |
1974年 | 12篇 |
1973年 | 10篇 |
1970年 | 12篇 |
1969年 | 7篇 |
排序方式: 共有3121条查询结果,搜索用时 15 毫秒
1.
First appearing in 2000, and with 20,000 copies sold as it entered its sixth printing in 2004, Richard Trudgen's Why Warriors Lie down and Die is a minor publishing phenomenon. Although scholarly forums have generally ignored the book, Christian media outlets, the popular press and neo‐conservative political activists have enthusiastically received and promoted it. An examination of the merits of Why Warriors Lie down and Die suggests that its popularity is only partly explained by original observations or insights on the part of the author. The most important explanation, and implication, of the book's remarkable take‐up lies in the opportune way in which it corresponds with now ascendant neo‐conservative political perspectives on indigenous policy. 相似文献
2.
3.
B R Kate 《Acta anatomica》1976,94(3):457-463
The usual term 'torsion angle of the femur' denotes the 'anteversion' of the neck of the femur as a whole, caused by the twist in the shaft of the femur rather than the twist in the neck. This has been differentiated from the twist in the neck of the femur around its own axis, termed 'torsion neck' and the values of both have been measured. To differentiate these two different phenomena, the term 'anteversion' is used to denote the usual angel described, while 'torsion neck' is sued to denote the twist in the neck around its own axis measured in this work. 1,000 femora from 21 cites in different parts of the country have been measured and the average anteversion angle calculated. The Indian average works out to be 12 degrees with a significantly (double) high value for females. The incidence of negative angle is 7% in the normal femora. All fractured femora invariably show a negative angle. The above information should be of great significance on orthopaedic surgery of the neck of the femur in these bones. The 'torsion neck' has been measured by tracing and its average reported as 30 degrees. 相似文献
4.
5.
The presence of free D-aspartic acid in rodents and man 总被引:4,自引:0,他引:4
D S Dunlop A Neidle D McHale D M Dunlop A Lajtha 《Biochemical and biophysical research communications》1986,141(1):27-32
Free D-aspartic acid is present in appreciable quantities in the brain and other tissues of rodents and in human blood. In the newborn rat, the highest concentration of D-aspartic acid was found in cerebral hemispheres, where, at 164 nmol/g (8.4% of the total aspartic acid), the level of D-aspartic acid exceeds that of many essential L-amino acids. The highest ratio of D- to total aspartic acid (38%) occurred in neonatal blood cells. In the adult rat, the highest concentration was present in the pituitary gland (127 nmol/g, 3.8%). Within the central nervous system marked regional differences are present and characteristic changes with development take place. In general, the levels of D-aspartic acid fall rapidly with increasing age. In cerebral hemispheres adult values (13 nmol/g, 0.43%) are approached within one week. D-aspartic acid concentrations may also be higher in young humans since fetal blood, taken from placental cord, contains 2.6 nmol/g (4.9%) of D-aspartic acid, a value five times that of adult human blood. These distributional patterns and developmental changes may be the result of differences in the ability of various tissues to dispose of an extraneous metabolite, or, reflect alterations in a specific functional requirement for D-aspartic acid. 相似文献
6.
7.
Kate Jolly 《BMJ (Clinical research ed.)》1991,303(6804):716-717
8.
Microbial ecology and activity in wine production influences grapevine health and productivity, conversion of sugar to ethanol during fermentation, wine aroma, wine quality and distinctiveness. Fungi in the vineyard ecosystem are not well described. Here, we characterized the spatial and temporal dynamics of fungal communities associated with the grapevine (grapes, flowers, leaves, and roots) and soils over an annual growth cycle in two vineyards to investigate the influences of grape habitat, plant developmental stage (flowering, fruit set, veraison, and harvest), vineyards, and climatic conditions. Fungi were influenced by both the grapevine habitat and plant development stage. The core microbiome was prioritized over space and time, and the identified core members drove seasonal community succession. The developmental stage of veraison, where the grapes undergo a dramatic change in metabolism and start accumulating sugar, coincided with a distinct shift in fungal communities. Co-occurrence networks showed strong correlations between the plant microbiome, the soil microbiome, and weather indices. Our study describes the complex ecological dynamics that occur in microbial assemblages over a growing season and highlight succession of the core community in vineyards. 相似文献
9.
10.
Controlled generation of reactive oxygen species orchestrates numerous physiological signaling events (Finkel, T. (2011) Signal transduction by reactive oxygen species. J. Cell Biol. 194, 7–15). A major cellular target of reactive oxygen species is the thiol side chain (RSH) of Cys, which may assume a wide range of oxidation states (i.e. −2 to +4). Within this context, Cys sulfenic (Cys-SOH) and sulfinic (Cys-SO2H) acids have emerged as important mechanisms for regulation of protein function. Although this area has been under investigation for over a decade, the scope and biological role of sulfenic/sulfinic acid modifications have been recently expanded with the introduction of new tools for monitoring cysteine oxidation in vitro and directly in cells. This minireview discusses selected recent examples of protein sulfenylation and sulfinylation from the literature, highlighting the role of these post-translational modifications in cell signaling. 相似文献