全文获取类型
收费全文 | 2483篇 |
免费 | 170篇 |
出版年
2023年 | 13篇 |
2022年 | 14篇 |
2021年 | 72篇 |
2020年 | 45篇 |
2019年 | 52篇 |
2018年 | 65篇 |
2017年 | 60篇 |
2016年 | 85篇 |
2015年 | 125篇 |
2014年 | 131篇 |
2013年 | 174篇 |
2012年 | 225篇 |
2011年 | 183篇 |
2010年 | 125篇 |
2009年 | 80篇 |
2008年 | 120篇 |
2007年 | 113篇 |
2006年 | 112篇 |
2005年 | 98篇 |
2004年 | 98篇 |
2003年 | 77篇 |
2002年 | 68篇 |
2001年 | 47篇 |
2000年 | 63篇 |
1999年 | 41篇 |
1998年 | 13篇 |
1997年 | 10篇 |
1996年 | 16篇 |
1995年 | 22篇 |
1993年 | 14篇 |
1992年 | 21篇 |
1991年 | 33篇 |
1990年 | 12篇 |
1989年 | 28篇 |
1988年 | 14篇 |
1987年 | 16篇 |
1986年 | 10篇 |
1985年 | 23篇 |
1984年 | 16篇 |
1983年 | 11篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1973年 | 9篇 |
1972年 | 9篇 |
1971年 | 7篇 |
1970年 | 5篇 |
1968年 | 5篇 |
1967年 | 4篇 |
排序方式: 共有2653条查询结果,搜索用时 0 毫秒
1.
Late Quaternary climate change,relict populations and present‐day refugia in the northern Atacama Desert: a case study from Quebrada La Higuera (18° S) 下载免费PDF全文
2.
3.
One of the unresolved questions in the field of cell division is how the actomyosin cytoskeleton remains structurally organized while generating the contractile force to divide one cell into two. In analogy to the actomyosin-based force production mechanism in striated muscle, it was originally proposed that contractile stress in the actomyosin ring is generated via a sliding filament mechanism within an organized sarcomere-like array. However, over the last 30 years, ultrastructural and functional studies have noted important distinctions between cytokinetic structures in dividing cells and muscle sarcomeres. Myosin-II motor activity is not always required, and there is evidence that actin depolymerization contributes to contraction. In this Review, the architecture and contractile dynamics of the actomyosin ring at the cell division plane will be discussed. We will report the interdisciplinary advances in the field as well as their integration into a mechanistic understanding of contraction in cell division and in other biological processes that rely on an actomyosin-based force-generating system. 相似文献
4.
5.
6.
A retrovirus carrying the polyomavirus middle T gene induces acute thrombocythemic myeloproliferative disease in mice. 总被引:2,自引:0,他引:2 下载免费PDF全文
A Fusco G Portella M Grieco G Tajana G Di Minno N Polli A Pinto 《Journal of virology》1988,62(1):361-365
Mice inoculated with an artificially constructed retrovirus carrying the middle T gene of polyomavirus develop acute myeloproliferative disease with severe thrombotic and hemorrhagic disorder and impaired platelet function. The megakaryocytic lineage appears to be a target for polyoma-murine leukemia virus infection and middle T gene expression. This newly described disease represents a unique model system for studying disorders of the megakaryocytic lineage. 相似文献
7.
8.
Kinetic modelling overcomes some of the drawbacks of purely intuitive thinking in integrating information accumulated on chemical reactions involved in oxidative stress. However, it is important to assess if current knowledge about the reactions that mediate lipid peroxidation already allows satisfactory modelling of this process in near-to-physiological conditions. In this paper, a set of increasingly complex in vitro experiments on antioxidants (a-tocopherol and ascorbate) and lipid peroxidation in heterogeneous systems is simulated. Quantitative to semiquantitative agreement is found between experimental and simulation results. In addition, this theoretical analysis provided useful insights, suggested new hypotheses and experiments and pointed out relevant aspects needing further research. The results encourage and serve as partial validation for the formulation of relatively detailed mathematical models of in vivo lipid peroxidation. Some important aspects of the formulation and analysis of such models are discussed. 相似文献
9.
Israel de Souza Pinto Bruna Dias das Chagas Andressa Alencastre Fuzari Rodrigues Adelson Luiz Ferreira Helder Ricas Rezende Rafaela Vieira Bruno Aloisio Falqueto José Dilermando Andrade-Filho Eunice Aparecida Bianchi Galati Paloma Helena Fernandes Shimabukuro Reginaldo Pe?anha Brazil Alexandre Afranio Peixoto 《PloS one》2015,10(10)
DNA barcoding has been an effective tool for species identification in several animal groups. Here, we used DNA barcoding to discriminate between 47 morphologically distinct species of Brazilian sand flies. DNA barcodes correctly identified approximately 90% of the sampled taxa (42 morphologically distinct species) using clustering based on neighbor-joining distance, of which four species showed comparatively higher maximum values of divergence (range 4.23–19.04%), indicating cryptic diversity. The DNA barcodes also corroborated the resurrection of two species within the shannoni complex and provided an efficient tool to differentiate between morphologically indistinguishable females of closely related species. Taken together, our results validate the effectiveness of DNA barcoding for species identification and the discovery of cryptic diversity in sand flies from Brazil. 相似文献
10.
A method based on the infection of CaCo-2 cells and molecular hybridization with a specific cDNA probe has been developed for the detection of infectious astroviruses in environmental samples. By this procedure wild-type astroviruses have been detected in water from an area where a concurrent gastroenteritis outbreak was reported. 相似文献