全文获取类型
收费全文 | 150篇 |
免费 | 0篇 |
专业分类
丛书文集 | 1篇 |
理论与方法论 | 5篇 |
现状及发展 | 116篇 |
研究方法 | 5篇 |
综合类 | 20篇 |
自然研究 | 3篇 |
出版年
2018年 | 5篇 |
2017年 | 2篇 |
2013年 | 1篇 |
2012年 | 5篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 2篇 |
1976年 | 9篇 |
1975年 | 1篇 |
1974年 | 4篇 |
1973年 | 9篇 |
1972年 | 5篇 |
1971年 | 2篇 |
1970年 | 5篇 |
1969年 | 1篇 |
1968年 | 9篇 |
1967年 | 1篇 |
1966年 | 4篇 |
1965年 | 1篇 |
1964年 | 5篇 |
1963年 | 1篇 |
1961年 | 2篇 |
1960年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有150条查询结果,搜索用时 968 毫秒
101.
Mariusz Flasiński 《Foundations of Science》1997,2(1):107-121
A survey of the main approaches in a mind study -oriented part of Artificial Intelligence is made focusing on controversial issues and extreme hypotheses. Various meanings of terms: "intelligence" and "artificial intelligence" are discussed. Limitations for constructing intelligent systems resulting from the lack of formalized models of cognitive activity are shown. The approaches surveyed are then recapitulated in the light of these limitations. 相似文献
102.
103.
Aging of the erythrocyte. XIV. ATP content does decrease 总被引:1,自引:0,他引:1
Summary ATP content shows a cell-age dependent decrease in bovine erythrocytes separated according to Murphy. An important point in
the evaluation of results lies in considering differences in the ATP consumption between cells of various age during separation.
The decrease in ATP occurs in spite of diminished ATPase activity in older cells.
We are indebted to Prof. W. Leyko for valuable remarks. 相似文献
104.
In rabbits naive to opiates or pretreated with morphine a selective morphine-induced facilitation of the Breuer-Hering inflation reflex is described. 相似文献
105.
106.
Résumé L'acide 2-chloroéthylphosphonique (un substitut de l'éthylène) augmente la féminité deCucurbita pepo L. On observe en même temps une augmentation des strogènes endogènes. Il est possible que ces derniers participent à la différenciation du sexe chez les plantes.
Acknowledgments: We are grateful to Amchem Products, Inc., Ambler (Pa., USA) for a gift sample of 2-chloroethylphosphonic acid (Ethrel formulation 68–250). 相似文献
Acknowledgments: We are grateful to Amchem Products, Inc., Ambler (Pa., USA) for a gift sample of 2-chloroethylphosphonic acid (Ethrel formulation 68–250). 相似文献
107.
Paweł Lipiński Agnieszka Styś Rafał R. Starzyński 《Cellular and molecular life sciences : CMLS》2013,70(1):23-38
Molecular iron metabolism and its regulation are least well understood in the fetal and early postnatal periods of mammalian ontogenic development. The scope of this review is to summarize recent progress in uncovering the molecular mechanisms of fetal iron homeostasis, introduce the molecules involved in iron transfer across the placenta, and briefly explain the role of iron transporters in the absorption of this microelement during early postnatal life. These issues are discussed and parallels are drawn with the relatively well-established system for elemental and heme iron regulation in adult mammals. We conclude that detailed investigations into the regulatory mechanisms of iron metabolism at early stages of development are required in order to optimize strategies to prevent neonatal iron deficiency. We propose that newborn piglets represent a suitable animal model for studies on iron deficiency anemia in neonates. 相似文献
108.
Beaulieu JP Bennett DP Fouqué P Williams A Dominik M Jørgensen UG Kubas D Cassan A Coutures C Greenhill J Hill K Menzies J Sackett PD Albrow M Brillant S Caldwell JA Calitz JJ Cook KH Corrales E Desort M Dieters S Dominis D Donatowicz J Hoffman M Kane S Marquette JB Martin R Meintjes P Pollard K Sahu K Vinter C Wambsganss J Woller K Horne K Steele I Bramich DM Burgdorf M Snodgrass C Bode M Udalski A Szymański MK Kubiak M Wieckowski T Pietrzyński G Soszyński I Szewczyk O Wyrzykowski L 《Nature》2006,439(7075):437-440
In the favoured core-accretion model of formation of planetary systems, solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars (the most common stars in our Galaxy), this model favours the formation of Earth-mass (M(o)) to Neptune-mass planets with orbital radii of 1 to 10 astronomical units (au), which is consistent with the small number of gas giant planets known to orbit M-dwarf host stars. More than 170 extrasolar planets have been discovered with a wide range of masses and orbital periods, but planets of Neptune's mass or less have not hitherto been detected at separations of more than 0.15 au from normal stars. Here we report the discovery of a 5.5(+5.5)(-2.7) M(o) planetary companion at a separation of 2.6+1.5-0.6 au from a 0.22+0.21-0.11 M(o) M-dwarf star, where M(o) refers to a solar mass. (We propose to name it OGLE-2005-BLG-390Lb, indicating a planetary mass companion to the lens star of the microlensing event.) The mass is lower than that of GJ876d (ref. 5), although the error bars overlap. Our detection suggests that such cool, sub-Neptune-mass planets may be more common than gas giant planets, as predicted by the core accretion theory. 相似文献
109.
Zusammenfassung In Hühnerembryonen wurde der Blutplasmaspiegel der Cystinaminopeptidase (Oxytocinase) bestimmt. Das Ferment konnte erst nach 19 Tagen Inkubationszeit nachgewiesen werden. Die Oxytocinasemenge steigt mit dem Alter der Embryonen an und erreicht nach 3 Tagen die Blutplasmawerte der adulten Hühner. 相似文献
110.