全文获取类型
收费全文 | 550篇 |
免费 | 42篇 |
专业分类
592篇 |
出版年
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 17篇 |
2015年 | 29篇 |
2014年 | 27篇 |
2013年 | 24篇 |
2012年 | 27篇 |
2011年 | 31篇 |
2010年 | 22篇 |
2009年 | 15篇 |
2008年 | 25篇 |
2007年 | 27篇 |
2006年 | 30篇 |
2005年 | 26篇 |
2004年 | 32篇 |
2003年 | 17篇 |
2002年 | 24篇 |
2001年 | 12篇 |
2000年 | 6篇 |
1999年 | 10篇 |
1998年 | 10篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 9篇 |
1994年 | 11篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 2篇 |
1971年 | 4篇 |
1969年 | 2篇 |
1957年 | 2篇 |
排序方式: 共有592条查询结果,搜索用时 0 毫秒
51.
Mironova GD Gritsenko E Gateau-Roesch O Levrat C Agafonov A Belosludtsev K Prigent AF Muntean D Dubois M Ovize M 《Journal of bioenergetics and biomembranes》2004,36(2):171-178
A possible role of palmitic acid/Ca2+ (PA/Ca2+) complexes in the cyclosporin-insensitive permeability transition in mitochondria has been studied. It has been shown that in the presence of Ca2+, PA induces a swelling of mitochondria, which is not inhibited by cyclosporin A. The swelling is accompanied by a drop in membrane potential, which cannot be explained only by a work of the Ca2+ uniporter. With time, the potential is restored. Evidence has been obtained indicating that the specific content of mitochondrial lipids would favor the PA/Ca2+ -induced permeabilization of the membrane. In experiments with liposomes, the PA/Ca2+ -induced membrane permeabilization was larger for liposomes formed from the mitochondrial lipids, as compared to the azolectin liposomes. Additionally, it has been found that in mitochondria of the TNF (tumor necrosis factor)-sensitive cells (WEHI-164 line), the content of PA is larger than in mitochondria of the TNF-insensitive cells (C6 line), with this difference being mainly provided by PA incorporated in phosphatidylethanolamine and especially, cardiolipin. The PA/Ca2+ -dependent mechanism of permeability transition in mitochondria might be related to some pathologies, e.g. myocardial ischemia. The heaviness of myocardial infarction of ischemic patients has been demonstrated to correlate directly with the content of PA in the human blood serum. 相似文献
52.
Kevin L. Schulte Daniel J. Friedman Titilope Dada Harvey L. Guthrey Edgard W. Costa Eric J. Tervo Ryan M. France John F. Geisz Myles A. Steiner 《Liver Transplantation》2024,14(10):2303367
Inverted metamorphic Ga0.3In0.7As photovoltaic converters with sub-0.60 eV bandgaps grown on InP and GaAs are presented. Threading dislocation densities are 1.3 ± 0.6 × 106 and 8.9 ± 1.7 × 106 cm−2 on InP and GaAs, respectively. The devices generate open-circuit voltages of 0.386 and 0.383 V, respectively, under irradiance producing a short-circuit current density of ≈10 A cm−2, yielding bandgap-voltage offsets of 0.20 and 0.21 V. Power and broadband reflectance measurements are used to estimate thermophotovoltaic (TPV) efficiency. The InP-based cell is estimated to yield 1.09 W cm−2 at 1100 °C versus 0.92 W cm−2 for the GaAs-based cell, with efficiencies of 16.8 versus 9.2%. The efficiencies of both devices are limited by sub-bandgap absorption, with power weighted sub-bandgap reflectances of 81% and 58%, respectively, the majority of which is assumed to occur in the graded buffers. The 1100 °C TPV efficiencies are estimated to increase to 24.0% and 20.7% in structures with the graded buffer removed, if previously demonstrated reflectance is achieved. These devices also have application to laser power conversion in the 2.0–2.3 µm atmospheric window. Peak laser power converter efficiencies of 36.8% and 32.5% are estimated under 2.0 µm irradiances of 1.86 and 2.81 W cm−2, respectively. 相似文献
53.
de Buron I France SG Connors VA Roumillat WA Tsoi LC 《The Journal of parasitology》2011,97(3):466-475
Two species of philometrid nematode, Philometra overstreeti and Philometroides paralichthydis, infect the southern flounder, Paralichthys lethostigma. Individuals of P. overstreeti are located between the teeth and inside the bony part of the branchial arches of the fish. Individuals of P. paralichthydis are associated with the bones of the buccal cavity and among muscles that control the dorsal and anal fins. Sequencing of part of the cytochrome oxidase I gene revealed 4 distinct genetic clades, each corresponding exactly to the 4 respective locations of the parasites in the host, suggesting the need for taxonomic revision. We hypothesized that each clade represented a separate species and, because the worms are morphologically indistinguishable, compared population level parameters of the clades comprising each currently recognized species. For each currently recognized species, the presence of worms from 1 clade was negatively correlated with the presence of worms from the other. Results also indicated significant differences between the clades in prevalences relative to both biotic and abiotic factors. Results clearly indicated major differences in the ecology of the philometrids constituting each clade. Taken as a whole, molecular and ecological data support the contention that the 4 genetic clades are likely 4 distinct species. 相似文献
54.
55.
56.
Magdalena Torres M. France Bader Dominique Aunis M. Teresa Miras-Portugal 《Journal of neurochemistry》1987,48(1):233-235
Chromaffin cells both recently isolated or in culture present a high-affinity adenosine transporter with a Km value of 1 microM. When cells were exposed to nerve growth factor (NGF; 10 ng/ml), the adenosine transporter affinity decreased to 3 microM. This value was maintained from 3 days after plating to the end of the culture period. A change in the transport capacity was observed, with a significant increase (approximately 200-260%) in NGF-cultured cells throughout the period studied. 相似文献
57.
A Neogene turtle from Brasil is described. It represents the first find of a new species close to the extant Podocnemis sextuberculata. Both species constitute a new clade in the genus. The synapomorphies they share and the differences between them are given. P. negrii nov. sp. is the second fossil species of the genus, after P. bassleri from the Neogene of Peru, which constitutes another clade with the extant P. expansa. The relationships between these two clades and the other species of the genus are not determinate. 相似文献
58.
59.
60.