全文获取类型
收费全文 | 2022篇 |
免费 | 39篇 |
国内免费 | 5篇 |
专业分类
化学 | 1524篇 |
晶体学 | 15篇 |
力学 | 26篇 |
综合类 | 1篇 |
数学 | 89篇 |
物理学 | 411篇 |
出版年
2022年 | 11篇 |
2021年 | 11篇 |
2020年 | 11篇 |
2019年 | 27篇 |
2018年 | 11篇 |
2017年 | 15篇 |
2016年 | 22篇 |
2015年 | 33篇 |
2014年 | 33篇 |
2013年 | 87篇 |
2012年 | 95篇 |
2011年 | 116篇 |
2010年 | 58篇 |
2009年 | 45篇 |
2008年 | 116篇 |
2007年 | 122篇 |
2006年 | 112篇 |
2005年 | 100篇 |
2004年 | 90篇 |
2003年 | 86篇 |
2002年 | 89篇 |
2001年 | 56篇 |
2000年 | 46篇 |
1999年 | 25篇 |
1998年 | 19篇 |
1997年 | 12篇 |
1996年 | 20篇 |
1995年 | 15篇 |
1994年 | 25篇 |
1993年 | 27篇 |
1992年 | 26篇 |
1991年 | 27篇 |
1990年 | 26篇 |
1989年 | 17篇 |
1988年 | 24篇 |
1987年 | 32篇 |
1986年 | 27篇 |
1985年 | 36篇 |
1984年 | 24篇 |
1983年 | 16篇 |
1982年 | 19篇 |
1981年 | 14篇 |
1980年 | 18篇 |
1979年 | 21篇 |
1978年 | 26篇 |
1977年 | 21篇 |
1976年 | 20篇 |
1975年 | 25篇 |
1974年 | 22篇 |
1973年 | 18篇 |
排序方式: 共有2066条查询结果,搜索用时 15 毫秒
151.
Aliu E Andringa S Aoki S Argyriades J Asakura K Ashie R Berns H Bhang H Blondel A Borghi S Bouchez J Burguet-Castell J Casper D Cavata C Cervera A Cho KO Choi JH Dore U Espinal X Fechner M Fernandez E Fukuda Y Gomez-Cadenas J Gran R Hara T Hasegawa M Hasegawa T Hayashi K Hayato Y Helmer RL Hill J Hiraide K Hosaka J Ichikawa AK Iinuma M Ikeda A Inagaki T Ishida T Ishihara K Ishii T Ishitsuka M Itow Y Iwashita T Jang HI Jeon EJ Jeong IS Joo K Jover G Jung CK Kajita T Kameda J Kaneyuki K Kato I 《Physical review letters》2005,94(8):081802
We present results for nu(mu) oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced nu(mu) beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy-dependent disappearance of nu(mu), which we presume have oscillated to nu(tau). The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma). 相似文献
152.
We introduce Hilbert phase microscopy (HPM) as a novel optical technique for measuring high transverse resolution quantitative phase images associated with optically transparent objects. Because of its single-shot nature, HPM is suitable for investigating rapid phenomena that take place in transparent structures such as biological cells. The potential of this technique for studying biological systems is demonstrated with measurements of red blood cells, and its ability to quantify dynamic processes on a millisecond scale is exemplified with measurements of evaporating micrometer-sized water droplets. 相似文献
153.
Aiura Y Yoshida Y Hase I Ikeda SI Higashiguchi M Cui XY Shimada K Namatame H Taniguchi M Bando H 《Physical review letters》2004,93(11):117005
We present detailed energy dispersions near the Fermi level along the high symmetry line GammaX on the monolayer and bilayer strontium ruthenates Sr2RuO4 and Sr3Ru2O7, determined by high-resolution angle-resolved photoemission spectroscopy. A kink in the dispersion is clearly shown for the both ruthenates. The energy position of the kink and the slope in the low-energy part near the Fermi level are almost identical between them, whereas the dispersion in the high-energy part varies, like the behavior of the kink for the cuprate superconductors. 相似文献
154.
An equilateral-triangular shape of three alpha clusters surrounded by excess neutrons is suggested for 14C, based on the molecular-orbit model. It is found that the attractive interaction between an excess neutron and an alpha particle stabilizes the K(pi)=0(+) and 3(-) rotational bands, which demonstrates an equilateral-triangular symmetry. This K(pi)=3(-) band at 3 MeV below the 10Be+alpha threshold energy corresponds to the experimentally observed band built on top of the second 3(-) state. A positive-parity rotational band (0(+), 2(+), 4(+)) arises similarly. These two bands suggest a molecular 3-alpha structure stabilized by the excess neutrons and can be viewed as a realization of the alpha crystallization in the dilute nuclear medium. 相似文献
155.
156.
157.
Ikeda S Sanuki R Miyachi H Miyashita H Taniguchi M Odashima K 《Journal of the American Chemical Society》2004,126(33):10331-10338
A Ni(0)/ZnCl(2) system effectively promotes the coupling of enones and alkene-tethered alkynes. In the reaction with 1,6-enynes, the oxidative cyclization of Ni(0) species on enones across the alkyne part followed by ZnCl(2)-promoted cleavage generates alkenylnickel intermediates. Subsequent migratory insertion of the tethered alkene occurs with 5-exo-cyclization. When the resulting sigma-alkylnickel intermediates have beta-hydrogen atoms, the reaction terminates by beta-hydrogen elimination to provide cyclopentane derivatives. On the other hand, a sigma-alkylnickel intermediate that does not have beta-hydrogen atoms undergoes the insertion of a second alkene unit to cause a domino effect via a three-fold C-C bond formation process with and without the cleavage of one C-C bond. 相似文献
158.
A new methodology for the synthesis of heparin building blocks has been developed. We describe novel efficient routes to both L-iduronic acid and D-glucuronic acid acceptors. Glycosylation with thioglycosides donors gave corresponding disaccharides in a regio- and stereoselective fashion. An improved approach to synthesizing azido-glucose thioglycoside donor to render azido-sugar from mannose via nucleophilic substitution is described. [reaction: see text] 相似文献
159.
We study theoretically the effect of deformed microelliptical cavities on lasing characteristics. We show that the transition of stationary lasing states from unidirectional rotational waves to a mixture of clockwise and anticlockwise rotational waves occurs when the shape of a disk is deformed to that of an ellipse. 相似文献
160.
A new efficient system for transporting saccharides through a liquid membrane has been constructed. The transport rates of saccharides were accelerated greatly by the cyclodextrin dimer 2; by contrast, the corresponding cyclodextrin monomer 1 was not effective at mediating saccharide transport. The transport rate of D-ribose through a chloroform liquid membrane was 17 times faster when the cyclodextrin dimer 2 was used as the transporter than when the cyclodextrin monomer 1 was used. Similarly the transport rate of methyl D-galactopyranoside was 16 times faster by 2 than by 1. 相似文献