全文获取类型
收费全文 | 1321篇 |
免费 | 120篇 |
国内免费 | 1篇 |
专业分类
1442篇 |
出版年
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 17篇 |
2020年 | 14篇 |
2019年 | 17篇 |
2018年 | 13篇 |
2017年 | 22篇 |
2016年 | 35篇 |
2015年 | 60篇 |
2014年 | 60篇 |
2013年 | 71篇 |
2012年 | 94篇 |
2011年 | 89篇 |
2010年 | 63篇 |
2009年 | 56篇 |
2008年 | 77篇 |
2007年 | 78篇 |
2006年 | 65篇 |
2005年 | 80篇 |
2004年 | 75篇 |
2003年 | 82篇 |
2002年 | 51篇 |
2001年 | 15篇 |
2000年 | 8篇 |
1999年 | 14篇 |
1998年 | 13篇 |
1997年 | 13篇 |
1996年 | 11篇 |
1995年 | 22篇 |
1994年 | 16篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 14篇 |
1989年 | 16篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 4篇 |
排序方式: 共有1442条查询结果,搜索用时 15 毫秒
101.
Lesley Gill 《American anthropologist》1999,101(3):681-682
The Gender/Sexuality Reader: Culture, History, Political Economy. Roger N. Lancaster and Micaela di Leonardo. eds. New York; Routledge, 1997. 574 pp. 相似文献
102.
High‐frequency binge eating predicts weight gain among veterans receiving behavioral weight loss treatments
下载免费PDF全文
![点击此处可从《Obesity (Silver Spring, Md.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
103.
104.
Lesley Cottrell Carrie Rishel Christa Lilly Scott Cottrell Aaron Metzger Halima Ahmadi Bo Wang Xiaoming Li Bonita Stanton 《PloS one》2015,10(5)
In this study, we examined how adolescents compare monitoring efforts by their parents to those of a "good parent" standard and assessed the impact of these comparisons on adolescent self-disclosure and risk behavior and their perceptions of their parents'' monitoring knowledge. Survey responses from 519 adolescents (12–17 years) at baseline of a larger, longitudinal study examining parental monitoring and adolescent risk were examined. Adolescents’ “good parent comparisons” differed greatly by monitoring areas (e.g., telephone use, health, money); however, between 5.5% and 25.8% of adolescents believed their parents needed to monitor their activities more than they currently were monitoring. Alternatively, between 8.5% and 23.8% of adolescents believed their parents needed to monitor their activities less often. These perceptions significantly distinguished adolescents in terms of their level of disclosure, perceived monitoring knowledge, and risk involvement. Adolescents who viewed their parents as needing to monitor more were less likely to disclose information to their parents (p<.001), less likely to perceive their parents as having greater monitoring knowledge (p<.001), and more likely to be involved in a risk behaviors (p<.001) than adolescents who perceived their parents needed no change. Adolescent disclosure to a parent is a powerful predictor of adolescent risk and poor health outcomes. These findings demonstrate that adolescents'' comparisons of their parents'' monitoring efforts can predict differences in adolescent disclosure and future risk. Obtaining adolescent "good parent" comparisons may successfully identify intervention opportunities with the adolescent and parent by noting the areas of need and direction of monitoring improvement. 相似文献
105.
David Grimaldi Paul S. Ginsberg Lesley Thayer Shane McEvey Martin Hauser Michael Turelli Brian Brown 《PloS one》2015,10(4)
Urban landscapes are commonly considered too mundane and corrupted to be biotically interesting. Recent insect surveys employing 29 Malaise traps throughout Los Angeles, California, however, have uncovered breeding populations of two unexpected species of one of the most studied and familiar groups of organisms, Drosophila “fruit” flies. Unlike most introduced species of drosophilids, which breed in fresh or decaying fruits, these are specialized flower-breeders. A common species in the survey was Drosophila (Drosophila) gentica Wheeler and Takada, previously collected only once, in El Salvador. It belongs to the flavopilosa species group, all species of which have been known until now from central Chile, Argentina and Uruguay, to Veracruz, Mexico and the Caribbean, breeding in flowers of Cestrum (“jessamine”) and Sessea (Solanaceae). The Los Angeles populations are probably breeding in a native and/or introduced Cestrum; in addition, populations in San Luis Obispo County were visiting ornamental Cestrum. Drosophila gentica occurs as far north as San Francisco, where it was found breeding in Cestrum aurantiacum. D. gentica is redescribed and figured in detail for diagnostic and identification purposes. Specimens from Jamaica previously identified as D. gentica are a distinct species but are not formally described in lieu of complete male specimens. Rare in the Malaise traps was Drosophila (Sophophora) flavohirta Malloch, a common species in Australia on the blossoms of native Myrtaceae, found on introduced Eucalyptus in South Africa and both Eucalyptus and Syzygium in Madagascar; adults feed on myrtaceous pollen and nectar, larvae breed in the flowers. It is also redescribed in detail, including its unusual egg. This is the first New World report of this species; DNA sequences confirm it is a morphologically highly aberrant member of the D. melanogaster species group. This study reveals how intensive field sampling can uncover remarkable biodiversity in even the most urbanized areas. 相似文献
106.
K. Lesley Szostek Peter H. Becker Barbara C. Meyer Stefan R. Sudmann Heribert Zintl 《Ibis》2014,156(1):48-59
Density is known to be an important factor in population size regulation. Several mechanisms of density limitation have been identified in colonial birds. We studied competition in Common Terns Sterna hirundo to assess whether the factor limiting reproductive output was competition for nest‐sites, which is dependent on local nest density, or density‐dependent competition for food resources, which is dependent on overall colony size using the same foraging area. We found strong associations of both colony size and nest density with reproductive output in five colonies of Common Terns in three different habitats (one marine, two freshwater). Based on detailed long‐term datasets of six separate sub‐colonies of the Banter See colony that differed in nest density, we found that reproductive success was not related to nest density but to overall colony size, possibly a result of resource depletion and food competition. We also found carry‐over effects of colony size during rearing on post‐fledging return rate. These results have important implications for the conservation management plans aimed at recovering declining populations of Common Terns. 相似文献
107.
108.
Nina V Chichkova Jane Shaw Raisa A Galiullina Georgina E Drury Alexander I Tuzhikov Sang Hyon Kim Markus Kalkum Teresa B Hong Elena N Gorshkova Lesley Torrance Andrey B Vartapetian Michael Taliansky 《The EMBO journal》2010,29(6):1149-1161
Caspases are cysteine‐dependent proteases and are important components of animal apoptosis. They introduce specific breaks after aspartate residues in a number of cellular proteins mediating programmed cell death (PCD). Plants encode only distant homologues of caspases, the metacaspases that are involved in PCD, but do not possess caspase‐specific proteolytic activity. Nevertheless, plants do display caspase‐like activities indicating that enzymes structurally distinct from classical caspases may operate as caspase‐like proteases. Here, we report the identification and characterisation of a novel PCD‐related subtilisin‐like protease from tobacco and rice named phytaspase (plant aspartate‐specific protease) that possesses caspase specificity distinct from that of other known caspase‐like proteases. We provide evidence that phytaspase is synthesised as a proenzyme, which is autocatalytically processed to generate the mature enzyme. Overexpression and silencing of the phytaspase gene showed that phytaspase is essential for PCD‐related responses to tobacco mosaic virus and abiotic stresses. Phytaspase is constitutively secreted into the apoplast before PCD, but unexpectedly is re‐imported into the cell during PCD providing insights into how phytaspase operates. 相似文献
109.
110.
The N-terminal domain of PMTV TGB1 movement protein is required for nucleolar localization, microtubule association, and long-distance movement 总被引:1,自引:0,他引:1
Wright KM Cowan GH Lukhovitskaya NI Tilsner J Roberts AG Savenkov EI Torrance L 《Molecular plant-microbe interactions : MPMI》2010,23(11):1486-1497
The triple-gene-block (TGB)1 protein of Potato mop-top virus (PMTV) was fused to fluorescent proteins and expressed in epidermal cells of Nicotiana benthamiana under the control of the 35S promoter. TGB1 fluorescence was observed in the cytoplasm, nucleus, and nucleolus and occasionally associated with microtubules. When expressed from a modified virus (PMTV.YFP-TGB1) which formed local lesions but was not competent for systemic movement, yellow fluorescent protein (YFP)-TGB1 labeled plasmodesmata in cells at the leading edge of the lesion and plasmodesmata, microtubules, nuclei, and nucleoli in cells immediately behind the leading edge. Deletion of 84 amino acids from the N-terminus of unlabeled TGB1 within the PMTV genome abolished movement of viral RNA to noninoculated leaves. When the same deletion was introduced into PMTV.YFP-TGB1, labeling of microtubules and nucleoli was abolished. The N-terminal 84 amino acids of TGB1 were fused to green fluorescent protein (GFP) and expressed in epidermal cells where GFP localized strongly to the nucleolus (not seen with unfused GFP), indicating that these amino acids contain a nucleolar localization signal; the fusion protein did not label microtubules. This is the first report of nucleolar and microtubule association of a TGB movement protein. The results suggest that PMTV TGB1 requires interaction with nuclear components and, possibly, microtubules for long-distance movement of viral RNA. 相似文献