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81.
This issue of Systemic Practice and Action Research focuses on systemic thinking in China. It results from considerable efforts invested in the project by Gerald Midgley and Jennifer Wilby. I am very grateful to Gerald and Jennifer, who have made available to our readership important research issues that would otherwise remain published only in the Chinese language. Inevitably a huge amount of editorial work is required when assisting people not fluent in the English language so that their papers are raised to a standard suitable for publication in a journal published in English. In addition, Gerald and Jennifer have put together a series of papers that make up an interesting whole that tells an important story. Thanks are extended to Gerald and Jennifer for this contribution. 相似文献
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Systemic Practice and Action Research - 相似文献
83.
Louis A. Somma 《西北部美国博物学家》2011,49(2)
The microenvironment of the nest surrounding most reptilian eggs is known to have a strong influence on the growth and development of embryos. This is particularly true of substrate moisture content. The results of this study suggest that neonatal body size (SVL) increases with increasing substrate wetness in the prairie skink, Eumeces septentrionalis . These results agree with studies conducted on other species of reptiles. This study is the first to provide evidence for this relationship in a scineid lizard. 相似文献
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The delivery of extraterrestrial organic molecules to Earth by meteorites may have been important for the origin and early evolution of life. Indigenous amino acids have been found in meteorites-over 70 in the Murchison meteorite alone. Although it has been generally accepted that the meteoritic amino acids formed in liquid water on a parent body, the water in the Murchison meteorite is depleted in deuterium relative to the indigenous organic acids. Moreover, the meteoritical evidence for an excess of laevo-rotatory amino acids is hard to understand in the context of liquid-water reactions on meteorite parent bodies. Here we report a laboratory demonstration that glycine, alanine and serine naturally form from ultraviolet photolysis of the analogues of icy interstellar grains. Such amino acids would naturally have a deuterium excess similar to that seen in interstellar molecular clouds, and the formation process could also result in enantiomeric excesses if the incident radiation is circularly polarized. These results suggest that at least some meteoritic amino acids are the result of interstellar photochemistry, rather than formation in liquid water on an early Solar System body. 相似文献
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Synthetic GPI as a candidate anti-toxic vaccine in a model of malaria 总被引:20,自引:0,他引:20
The malaria parasite Plasmodium falciparum infects 5-10% of the world's population and kills two million people annually. Fatalities are thought to result in part from pathological reactions initiated by a malarial toxin. Glycosylphosphatidylinositol (GPI) originating from the parasite has the properties predicted of a toxin; however, a requirement for toxins in general and GPI in particular in malarial pathogenesis and fatality remains unproven. As anti-toxic vaccines can be highly effective public health tools, we sought to determine whether anti-GPI vaccination could prevent pathology and fatalities in the Plasmodium berghei/rodent model of severe malaria. The P. falciparum GPI glycan of the sequence NH(2)-CH(2)-CH(2)-PO(4)-(Man alpha 1-2)6Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcNH(2)alpha 1-6myo-inositol-1,2-cyclic-phosphate was chemically synthesized, conjugated to carriers, and used to immunize mice. Recipients were substantially protected against malarial acidosis, pulmonary oedema, cerebral syndrome and fatality. Anti-GPI antibodies neutralized pro-inflammatory activity by P. falciparum in vitro. Thus, we show that GPI is a significant pro-inflammatory endotoxin of parasitic origin, and that several disease parameters in malarious mice are toxin-dependent. GPI may contribute to pathogenesis and fatalities in humans. Synthetic GPI is therefore a prototype carbohydrate anti-toxic vaccine against malaria. 相似文献
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本文叙述四川重庆附近地区6个亚热带草地类型的植物区系组成、植物量和植冠结构.这6个亚热带草地类型分别属于半自然样地和栽培样地的两个不同植物群落.所有的草地类型是非常明显地由5个优势种组成.这两个植物群落的植冠结构虽然有些区别,但更重要的是这两个群落结构类型却完全不同.这两个结构类型决定于优势种是禾草类或蕨类植物.植冠内部的光气候决定于植冠的结构.蒙斯(Momsi)和塞克(Saeki)模型可以很好地描述禾草类占优势的植冠中的光气候,但不能应用于以蕨类植物占优势的植冠中的光气候. 相似文献
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Xu Y Padiath QS Shapiro RE Jones CR Wu SC Saigoh N Saigoh K Ptácek LJ Fu YH 《Nature》2005,434(7033):640-644
Familial advanced sleep phase syndrome (FASPS) is a human behavioural phenotype characterized by early sleep times and early-morning awakening. It was the first human, mendelian circadian rhythm variant to be well-characterized, and was shown to result from a mutation in a phosphorylation site within the casein kinase I (CKI)-binding domain of the human PER2 gene. To gain a deeper understanding of the mechanisms of circadian rhythm regulation in humans, we set out to identify mutations in human subjects leading to FASPS. We report here the identification of a missense mutation (T44A) in the human CKIdelta gene, which results in FASPS. This mutant kinase has decreased enzymatic activity in vitro. Transgenic Drosophila carrying the human CKIdelta-T44A gene showed a phenotype with lengthened circadian period. In contrast, transgenic mice carrying the same mutation have a shorter circadian period, a phenotype mimicking human FASPS. These results show that CKIdelta is a central component in the mammalian clock, and suggest that mammalian and fly clocks might have different regulatory mechanisms despite the highly conserved nature of their individual components. 相似文献