全文获取类型
收费全文 | 632篇 |
免费 | 26篇 |
国内免费 | 1篇 |
专业分类
659篇 |
出版年
2022年 | 13篇 |
2021年 | 14篇 |
2020年 | 18篇 |
2019年 | 16篇 |
2018年 | 26篇 |
2017年 | 13篇 |
2016年 | 25篇 |
2015年 | 36篇 |
2014年 | 41篇 |
2013年 | 59篇 |
2012年 | 39篇 |
2011年 | 49篇 |
2010年 | 34篇 |
2009年 | 20篇 |
2008年 | 38篇 |
2007年 | 30篇 |
2006年 | 26篇 |
2005年 | 27篇 |
2004年 | 14篇 |
2003年 | 18篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1991年 | 3篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 5篇 |
1972年 | 4篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 3篇 |
1968年 | 1篇 |
1966年 | 2篇 |
1906年 | 1篇 |
排序方式: 共有659条查询结果,搜索用时 15 毫秒
1.
2.
3.
Recent studies of the motor system using functional imaging have served to emphasize the complexity of the control of even relatively simple movements. The results of these studies suggest that the behavioral context of the movement is an important determinant of functional activation within cortical motor areas. 相似文献
4.
Chang-chi Chu James S. Buckner Kamil Karut Thomas P. Freeman Dennis R. Nelson Thomas J. Hennebeny 《Insect Science》2003,10(2):121-129
Abstract Size and weight measurements were made for all the life stages of Bemisia tabaci (Gennadius) B biotype from field grown cotton ( Gossypium hirsutum L.) and cantaloupe ( Cucumis melo L., var. cantalupensis ) in Phoenix, AZ and Fargo, ND, USA in 2000 and 2001. Nymphal volumes were derived from the measurements. The average nymphal volume increase for settled 1 st to the late 4th instar was exponential. The greatest increase in body volume occurred during development from the 3rd to early 4th instar. Nymphs on cotton leaves were wider, but not longer compared with those on cantaloupe. Ventral and dorsal depth ratios of nymphal bodies from 1 st to late 4th instars from cantaloupe leaves were significantly greater compared with those from cotton leaves. During nymphal development from 1st to 4th instar, the average (from the two host species) ventral body half volume increased by nearly 51 times compared with an increase of 28 times for the dorsal body half volume. Adult female and male average lengths, from heads to wing tips, were 1 126 μm and 953 μm, respectively. Average adult female and male weights were 39 and 17 μg, respectively. Average widths, lengths, and weights of eggs from cotton and cantaloupe were, 99 μm, 197 μm, and 0.8 μg, respectively. Average widths, lengths, and weights for exuviae of non-parasitized nymphs from both cotton and cantaloupe were 492 μm, 673 μm, and 1.20 μg, respectively; and widths, lengths, and weights of parasitized nymph exuviae were 452 μm, 665 μm, and 3.62 μg, respectively. Both exuviae from non-parasitized and parasitized nymphs from cotton leaves were wider, longer, and heavier than those from cantaloupe leaves. 相似文献
5.
I. Szumiel M. Kapiszewska M. Kruszewski T. Iwaneńko C. S. Lange 《Radiation and environmental biophysics》1995,34(2):113-119
Cells from the L5178Y murine lymphoma subline LY-R are twice as resistent to killing by ionizing radiation than the subline LY-S. In contrast, LY-R cells are more sensitive to killing by H2O2, the effect being more pronounced at 37 °C than 0 °C. Initial DNA damage after H2O2 treatment (both temperatures, 5 min) has been estimated by the comet assay (single-cell gel electrophoresis) and fluorescent halo technique. According to both methods, the initial damage is significantly higher in LY-R cells, particularly that inflicted at O °C. Differences between DNA unwinding and rewinding abilities at pH 9 and 6.9 (estimated by the fluorescent halo technique) point to a considerable difference in pH-9-labile damage between the sublines, as observed previously for x-irradiated cells (Kapiszewska et al. 1992). In contrast to findings with x-irradiated cells, however, after H2O2 treatment this damage is more extensive in LY-R cells than in LY-S cells. Thus, the initial pH-9-labile damage corresponds to the pattern of sensitivity to H2O2 and x-rays. We suggest that this is caused by different proportions of cuprous and ferric ions found in the nuclei of LY sublines and by the different ability of these ions to react with H2O2 and water radiolysis products. The copper/iron ratio in the nucleus is 1.31 in LY-R cells and 4.84 in LY-S cells. 相似文献
6.
7.
8.
Dagmar Jičínská Eduard Brabec Marcel Rejmánek Jan Jeník Joří Haager Josef Holub Věroslav Samek Hana Rambousková Josef Holub Marie Naděžda Končalová Robert Neuhäusl Josev Kyncl František Krahuleo Jaroslav Dobrý Blanka Úlehlová Jiří Úlehla Eliška Rybníčková Kamil Rybníček 《Folia Geobotanica》1982,17(4):431-448
9.
10.