全文获取类型
收费全文 | 121篇 |
免费 | 0篇 |
专业分类
系统科学 | 4篇 |
理论与方法论 | 1篇 |
现状及发展 | 27篇 |
研究方法 | 10篇 |
综合类 | 77篇 |
自然研究 | 2篇 |
出版年
2016年 | 1篇 |
2013年 | 1篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 10篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 3篇 |
1967年 | 4篇 |
1965年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 31 毫秒
81.
Of the over 200 known extrasolar planets, just 14 pass in front of and behind their parent stars as seen from Earth. This fortuitous geometry allows direct determination of many planetary properties. Previous reports of planetary thermal emission give fluxes that are roughly consistent with predictions based on thermal equilibrium with the planets' received radiation, assuming a Bond albedo of approximately 0.3. Here we report direct detection of thermal emission from the smallest known transiting planet, HD 149026b, that indicates a brightness temperature (an expression of flux) of 2,300 +/- 200 K at 8 microm. The planet's predicted temperature for uniform, spherical, blackbody emission and zero albedo (unprecedented for planets) is 1,741 K. As models with non-zero albedo are cooler, this essentially eliminates uniform blackbody models, and may also require an albedo lower than any measured for a planet, very strong 8 microm emission, strong temporal variability, or a heat source other than stellar radiation. On the other hand, an instantaneous re-emission blackbody model, in which each patch of surface area instantly re-emits all received light, matches the data. This planet is known to be enriched in heavy elements, which may give rise to novel atmospheric properties yet to be investigated. 相似文献
82.
Structure and mechanism of copper, zinc superoxide dismutase 总被引:26,自引:0,他引:26
Copper, zinc superoxide dismutase (SOD) catalyses the very rapid two-step dismutation of the toxic superoxide radical (O-2) to molecular oxygen and hydrogen peroxide through the alternate reduction and oxidation of the active-site copper. We report here that after refitting and further refinement of the previous 2 A structure of SOD2, analysis of the new model and its calculated molecular surface shows an extensive surface topography of sequence-conserved residues stabilized by underlying tight packing and H-bonding. There is a single, highly complementary position for O-2 to bind to both the Cu(II) and activity-important Arg 141 with correct geometry; two water molecules form a ghost of the superoxide in this position. The geometry and molecular surface of the active site, together with biochemical data, suggest a specific model for the enzyme mechanism. 相似文献
83.
Jong Sik Yoon R. H. Richardson M. R. Wheeler 《Cellular and molecular life sciences : CMLS》1973,29(5):639-641
Zusammenfassung Es wird eine verbesserte Methode zur Herstellung von Quetschpräparaten von Speicheldrüsenchromosomen beschrieben. Die Methode gibt scharfe Bilder der feinsten Chromosomenbänder auf klarem Hintergrund.
Research supported by U.S. Public Health Service Research Grants No. GM-11609 and GM-19616 from the National Institute of General Medical Sciences. 相似文献
Research supported by U.S. Public Health Service Research Grants No. GM-11609 and GM-19616 from the National Institute of General Medical Sciences. 相似文献
84.
85.
DNA methylation and the regulation of gene transcription 总被引:28,自引:0,他引:28
86.
Mutations in IRF6 cause Van der Woude and popliteal pterygium syndromes 总被引:25,自引:0,他引:25
Kondo S Schutte BC Richardson RJ Bjork BC Knight AS Watanabe Y Howard E de Lima RL Daack-Hirsch S Sander A McDonald-McGinn DM Zackai EH Lammer EJ Aylsworth AS Ardinger HH Lidral AC Pober BR Moreno L Arcos-Burgos M Valencia C Houdayer C Bahuau M Moretti-Ferreira D Richieri-Costa A Dixon MJ Murray JC 《Nature genetics》2002,32(2):285-289
87.
A rho-recognition site on phage lambda cro-gene mRNA 总被引:1,自引:0,他引:1
88.
Th. Cooper M. Jellinek Teresa Pinakatt A. W. Richardson 《Cellular and molecular life sciences : CMLS》1965,21(1):28-29
Résumé L'administration intraveineuse de pyridoxine et pyridoxal (10 mg/kg) à des rats anesthésiés inhibe l'augmentation du rendement du cocur. En même temps, une hyperthermie est provoquée par l'irradiation du corps entier avec des ondes de longueur minime (2,450 Mc. c.w. 0.08/w/cm2). Cet effet peut être attribué à l'interaction de ces composés d'amines vasoactifs libérés pendant l'irradiation. 相似文献
89.
M. Zacco E. M. Richardson J. O. Crittenden F. C. Dohan J. L. Hollander 《Cellular and molecular life sciences : CMLS》1955,11(7):279-280
Riassunto In pazienti affetti da artrite reumatoide viene iniettato cortisone acetato, idrocortisone acetato, o idrocortisone, nel cavo sinoviale artritico.La durata del riassorbimento di questi 17-idrossicorticoidi; la loro distribuzione nelle cellule e nel fluido articolare e nelle cellule del rivestimento sinoviale; le andamento del processo idrolitico dei composti acetati, studiati con mezzi chimici e cromatografici, si prestano a commenti utili ad interpretare la maggiore efficacia locale dell'idrocortisone.
Supported by a grant from the Helen Augusta Parkhill Foundation.—Communication at the 8th International Congress of Rheumatic Diseases, Geneva, August 1953. 相似文献
Supported by a grant from the Helen Augusta Parkhill Foundation.—Communication at the 8th International Congress of Rheumatic Diseases, Geneva, August 1953. 相似文献