全文获取类型
收费全文 | 90篇 |
免费 | 0篇 |
专业分类
系统科学 | 2篇 |
现状及发展 | 24篇 |
研究方法 | 11篇 |
综合类 | 53篇 |
出版年
2016年 | 1篇 |
2012年 | 4篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1969年 | 2篇 |
1968年 | 3篇 |
1967年 | 3篇 |
1966年 | 1篇 |
排序方式: 共有90条查询结果,搜索用时 15 毫秒
11.
M. Sasaki M. Ono S. Asada T. Yoshida 《Cellular and molecular life sciences : CMLS》1991,47(11-12):1229-1231
The discovery that drones of the Japanese honeybee (Apis cerana japonica) pollinate the oriental orchid (Cymbidium pumilum) is reported. Drones are attracted to the orchid flower aroma mainly during their mating flights in April through May. Some drones cluster on the flower racemes and others insert their heads deep into the flowers. Drones with pollinia on their scutellum visit other orchids, which facilitates pollination. Individual workers and swarming colonies are also strongly attracted by the flower aroma, but the allopatric western honeybee (Apis mellifera) is not attracted. 相似文献
12.
13.
N. Sasaki M. Matsuzaki T. Okabe Y. Imai Y. Kaneko F. Matsuzaki 《Cellular and molecular life sciences : CMLS》1983,39(3):330-331
Summary Both 12-O-tetradecanoyl-phorbol-1-acetate and teleocidin B stimulated the secretion of human chorionic gonadotropin by cultured choriocarcinoma cells. These tumor promoters also stimulated production of progesterone in the cells. However, the 2 tumor promoters did not exert a marked effect on the cellular binding of epidermal growth factor that also had a stimulatory effect on production of these hormones. 相似文献
14.
15.
16.
17.
Proliferation of human lymphocytes in culture 总被引:9,自引:0,他引:9
18.
Zusammenfassung Die Aktivität dreier mucopolysac-charidsynthetisierender Enzyme in der Haut normaler Mäuse wurde von Cortison und DOCA gehemmt, von Östradiol und Testosteron hingegen stimuliert. Eine Ausnahme bildet die Gruppe testosteronbehandelter weiblicher Mäuse. 相似文献
19.
Changes in membrane potential affect ion channels and transporters, which then alter intracellular chemical conditions. Other signalling pathways coupled to membrane potential have been suggested but their underlying mechanisms are unknown. Here we describe a novel protein from the ascidian Ciona intestinalis that has a transmembrane voltage-sensing domain homologous to the S1-S4 segments of voltage-gated channels and a cytoplasmic domain similar to phosphatase and tensin homologue. This protein, named C. intestinalis voltage-sensor-containing phosphatase (Ci-VSP), displays channel-like 'gating' currents and directly translates changes in membrane potential into the turnover of phosphoinositides. The activity of the phosphoinositide phosphatase in Ci-VSP is tuned within a physiological range of membrane potential. Immunocytochemical studies show that Ci-VSP is expressed in Ciona sperm tail membranes, indicating a possible role in sperm function or morphology. Our data demonstrate that voltage sensing can function beyond channel proteins and thus more ubiquitously than previously realized. 相似文献
20.
Developing space weathering on the asteroid 25143 Itokawa 总被引:1,自引:0,他引:1
Hiroi T Abe M Kitazato K Abe S Clark BE Sasaki S Ishiguro M Barnouin-Jha OS 《Nature》2006,443(7107):56-58
Puzzlingly, the parent bodies of ordinary chondrites (the most abundant type of meteorites) do not seem to be abundant among asteroids. One possible explanation is that surfaces of the parent bodies become optically altered, to become the S-type asteroids which are abundant in the main asteroid belt. The process is called 'space weathering'-it makes the visible and near-infrared reflectance spectrum of a body darker and redder. A recent survey of small, near-Earth asteroids suggests that the surfaces of small S asteroids may have developing stages of space weathering. Here we report that a dark region on a small (550-metre) asteroid-25143 Itokawa-is significantly more space-weathered than a nearby bright region. Spectra of both regions are consistent with those of LL5-6 chondrites after continuum removal. A simple calculation suggests that the dark area has a shorter mean optical path length and about 0.04 per cent by volume more nanophase metallic iron particles than the bright area. This clearly shows that space-weathered materials accumulate on small asteroids, which are likely to be the parent bodies of LL chondrites. We conclude that, because LL meteorites are the least abundant of ordinary (H, L, and LL) chondrites, there must be many asteroids with ordinary-chondrite compositions in near-Earth orbits. 相似文献