首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   88篇
  免费   0篇
  国内免费   2篇
系统科学   2篇
理论与方法论   1篇
现状及发展   23篇
研究方法   11篇
综合类   53篇
  2019年   1篇
  2018年   2篇
  2017年   2篇
  2016年   1篇
  2013年   2篇
  2012年   3篇
  2011年   3篇
  2010年   1篇
  2008年   4篇
  2007年   7篇
  2006年   6篇
  2005年   6篇
  2004年   6篇
  2003年   2篇
  2002年   5篇
  2001年   3篇
  2000年   3篇
  1997年   1篇
  1993年   1篇
  1989年   1篇
  1988年   1篇
  1987年   4篇
  1986年   4篇
  1985年   1篇
  1984年   1篇
  1980年   1篇
  1979年   6篇
  1978年   4篇
  1974年   1篇
  1972年   3篇
  1971年   1篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
排序方式: 共有90条查询结果,搜索用时 15 毫秒
11.
12.
G Chihara  Y Maeda  J Hamuro  T Sasaki  F Fukuoka 《Nature》1969,222(5194):687-688
  相似文献   
13.
Zusammenfassung Es werden Veränderungen der MAO-Aktivität im Rückenmark oder in der Medulla oblongata von Ratten beschrieben, die durch die Sektion des N. ischiadicus oder des N. hypoglossus verursacht wurden.  相似文献   
14.
Photocatalyst releasing hydrogen from water   总被引:4,自引:0,他引:4  
Maeda K  Teramura K  Lu D  Takata T  Saito N  Inoue Y  Domen K 《Nature》2006,440(7082):295
Direct splitting of water using a particulate photocatalyst would be a good way to produce clean and recyclable hydrogen on a large scale, and in the past 30 years various photocatalysts have been found that function under visible light. Here we describe an advance in the catalysis of the overall splitting of water under visible light: the new catalyst is a solid solution of gallium and zinc nitrogen oxide, (Ga(1-x)Zn(x))(N(1-x)O(x)), modified with nanoparticles of a mixed oxide of rhodium and chromium. The mixture functions as a promising and efficient photocatalyst in promoting the evolution of hydrogen gas.  相似文献   
15.
为了现实有效地离散弹性体材料拌合的数值模拟,采用离散元法,开发了离散弹性体材料拌合离散元模拟系统.通过塑料球落下拌合实验对数值模拟系统进行了验证.实验结果与计算结果接近,表明该系统具有可信性.应用数值模拟系统对现有拌合装置的拌合原理进行了分析,阐明了现有拌合装置的问题,开发了一种新型拌合装置,并对其进行了实验验证和数值模拟.结果表明新型拌合装置的拌合能力高.该材料拌合离散元模拟系统与参数确定方法能够合理地模拟离散体的拌合.  相似文献   
16.
Miyai E  Sakai K  Okano T  Kunishi W  Ohnishi D  Noda S 《Nature》2006,441(7096):946
Compact lasers that can produce a range of beam patterns are important for progress in several areas, including the improvement of optical tweezers, ultra-high-density optical memory and microfluidics. Here we engineer photonic crystals to generate semiconductor lasers that produce a range of beam patterns while maintaining stable single-mode oscillation. Our results could contribute to the realization of compact lasers that are capable of producing diverse beam patterns on demand.  相似文献   
17.
Mazzali PA  Deng J  Nomoto K  Sauer DN  Pian E  Tominaga N  Tanaka M  Maeda K  Filippenko AV 《Nature》2006,442(7106):1018-1020
Supernovae connected with long-duration gamma-ray bursts (GRBs) are hyper-energetic explosions resulting from the collapse of very massive stars ( approximately 40 M\circ, where M\circ is the mass of the Sun) stripped of their outer hydrogen and helium envelopes. A very massive progenitor, collapsing to a black hole, was thought to be a requirement for the launch of a GRB. Here we report the results of modelling the spectra and light curve of SN 2006aj (ref. 9), which demonstrate that the supernova had a much smaller explosion energy and ejected much less mass than the other GRB-supernovae, suggesting that it was produced by a star whose initial mass was only approximately 20 M\circ. A star of this mass is expected to form a neutron star rather than a black hole when its core collapses. The smaller explosion energy of SN 2006aj is matched by the weakness and softness of GRB 060218 (an X-ray flash), and the weakness of the radio flux of the supernova. Our results indicate that the supernova-GRB connection extends to a much broader range of stellar masses than previously thought, possibly involving different physical mechanisms: a 'collapsar' (ref. 8) for the more massive stars collapsing to a black hole, and magnetic activity of the nascent neutron star for the less massive stars.  相似文献   
18.
The internal organs of animals often have left-right asymmetry. Although the formation of the anterior-posterior and dorsal-ventral axes in Drosophila is well understood, left-right asymmetry has not been extensively studied. Here we find that the handedness of the embryonic gut and the adult gut and testes is reversed (not randomized) in viable and fertile homozygous Myo31DF mutants. Myo31DF encodes an unconventional myosin, Drosophila MyoIA (also referred to as MyoID in mammals; refs 3, 4), and is the first actin-based motor protein to be implicated in left-right patterning. We find that Myo31DF is required in the hindgut epithelium for normal embryonic handedness. Disruption of actin filaments in the hindgut epithelium randomizes the handedness of the embryonic gut, suggesting that Myo31DF function requires the actin cytoskeleton. Consistent with this, we find that Myo31DF colocalizes with the cytoskeleton. Overexpression of Myo61F, another myosin I (ref. 4), reverses the handedness of the embryonic gut, and its knockdown also causes a left-right patterning defect. These two unconventional myosin I proteins may have antagonistic functions in left-right patterning. We suggest that the actin cytoskeleton and myosin I proteins may be crucial for generating left-right asymmetry in invertebrates.  相似文献   
19.
Chronic kidney disease (CKD), impairment of kidney function, is a serious public health problem, and the assessment of genetic factors influencing kidney function has substantial clinical relevance. Here, we report a meta-analysis of genome-wide association studies for kidney function-related traits, including 71,149 east Asian individuals from 18 studies in 11 population-, hospital- or family-based cohorts, conducted as part of the Asian Genetic Epidemiology Network (AGEN). Our meta-analysis identified 17 loci newly associated with kidney function-related traits, including the concentrations of blood urea nitrogen, uric acid and serum creatinine and estimated glomerular filtration rate based on serum creatinine levels (eGFRcrea) (P < 5.0 × 10(-8)). We further examined these loci with in silico replication in individuals of European ancestry from the KidneyGen, CKDGen and GUGC consortia, including a combined total of ~110,347 individuals. We identify pleiotropic associations among these loci with kidney function-related traits and risk of CKD. These findings provide new insights into the genetics of kidney function.  相似文献   
20.
M Okazaki  N Maeda  T Shiga 《Experientia》1986,42(7):842-843
Drifts of erythrocyte-flow lines due to inhomogeneous magnetic field in a laminar flow in a buffer solution are shown for the first time, and are interpreted as being due to the paramagnetism of hemoglobins included in the erythrocytes. The drifts were dependent on the hematocrit of the flowing erythrocyte suspension.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号