全文获取类型
收费全文 | 1559篇 |
免费 | 58篇 |
国内免费 | 11篇 |
专业分类
化学 | 1038篇 |
晶体学 | 51篇 |
力学 | 20篇 |
数学 | 97篇 |
物理学 | 422篇 |
出版年
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 19篇 |
2018年 | 19篇 |
2017年 | 11篇 |
2016年 | 26篇 |
2015年 | 32篇 |
2014年 | 30篇 |
2013年 | 83篇 |
2012年 | 56篇 |
2011年 | 72篇 |
2010年 | 55篇 |
2009年 | 44篇 |
2008年 | 68篇 |
2007年 | 95篇 |
2006年 | 68篇 |
2005年 | 63篇 |
2004年 | 85篇 |
2003年 | 72篇 |
2002年 | 55篇 |
2001年 | 48篇 |
2000年 | 26篇 |
1999年 | 35篇 |
1998年 | 23篇 |
1997年 | 25篇 |
1996年 | 25篇 |
1995年 | 23篇 |
1994年 | 30篇 |
1993年 | 45篇 |
1992年 | 35篇 |
1991年 | 24篇 |
1990年 | 14篇 |
1989年 | 18篇 |
1988年 | 20篇 |
1987年 | 10篇 |
1986年 | 12篇 |
1985年 | 26篇 |
1984年 | 16篇 |
1983年 | 13篇 |
1982年 | 12篇 |
1981年 | 25篇 |
1980年 | 16篇 |
1979年 | 23篇 |
1978年 | 17篇 |
1977年 | 14篇 |
1976年 | 9篇 |
1975年 | 12篇 |
1974年 | 16篇 |
1973年 | 10篇 |
1972年 | 8篇 |
排序方式: 共有1628条查询结果,搜索用时 31 毫秒
121.
Liu Z Kozeki T Suzuki Y Sarukura N Shimamura K Fukuda T Hirano M Hosono H 《Optics letters》2001,26(5):301-303
Chirped-pulse amplification in the ultraviolet region is demonstrated by use of a broadband Ce(3+): LiCaAlF(6) laser medium. A modified bow-tie-style four-pass amplifier pumped by 100-mJ, 266-nm pulses from a Q -switched Nd:YAG laser has a gain factor of 370 and delivers 6-mJ, 290-nm pulses. After dispersion compensation, the output pulses can be compressed to 115 fs. 相似文献
122.
A novel diode-pumped, efficient, quasi-end-pumping scheme that uses two lens ducts to achieve homogeneous pumping in a gain medium was proposed and evaluated. With this technique, room-temperature laser action at a pulse repetition frequency up to 20 Hz was demonstrated in 5%Tm, 0.5%Ho:LuLiF(4), which we grew by the Czochralski method. At 10 Hz a long-pulse laser output energy in excess of 24 mJ and a slope efficiency with respect to the incident pump energy of 10.7% were obtained. 相似文献
123.
M. Mihara R. Matsumiya K. Matsuta K. Shimomura M. Fukuda J. Komurasaki D. Nishimura D. Ishikawa T. Nagasawa T. Izumikawa T. Minamisono 《Hyperfine Interactions》2007,178(1-3):69-72
In order to study the local electronic structure of nitrogen impurity in rutile TiO2, we have measured double-quantum NMR spectra of short lived β-emitter 12N(I = 1, T 1/2 = 11 ms) implanted into a rutile single crystal by means of the β-NMR technique. The resonance line obtained at room temperature is well accounted for by the second order shift due to the quadrupole interaction at the oxygen substitutional site. The spectrum at 25 K has shown the other lines than the central diamagnetic line shifted by 10?15 kHz to both sides, which has been already shown in the previous data obtained with a different crystal orientation and an external field. The present results supports the existence of a paramagnetic state formed by the substitutional nitrogen impurities. 相似文献
124.
傅元勇 周书华T. Koike S. Kinoshita Y. Ma Y. Miura K. Miwa Y. Miyagi K. Shirotori T. Suzuki H. Tamura K. Tsukada M. Ukai K. Futatsukawa K. Hosomi M. Kawai M. Mimori N. Terada N. Maruyama K. Aoki H Fujioka Y Kakiguchi T. Nagae D. Nakajima H Noumi T Takahashi T.N. Takahashi A. Toyota M. Dairaku T. Fukuda S. Minami W. Imoto S. Aiimura K. Tanida 《中国物理快报》2007,24(8):2216-2218
From the ^12 C(π^+,K^+)^12 AC reaction the γ -rays of 261.6±0.24 ke V(7/2^+ →5/2^+)and 1481.7±0.7 ke V(1/2^+ →5/2^+) of ^11 A B,and 2667.3±2.8 keV(1^- 2 → 2^- 1)of ^12 A C hypernuclei have been identified using a large germanium detector array Hyperball2 at K6 beam line of KEK. The observed energies of the transitions 1481.7keV and 261.6 keV are significantly different from the values predicted by the shell model using the △ and SN parameters determined from the ^7 △ Li data. 相似文献
125.
D. -J. Qian H. Nakahara K. Fukuda K. -Z. Yang 《Journal of Dispersion Science and Technology》2013,34(3):1031-139
Monolayers of europium complexes on water surface have been directly visualized in the gas-liquid expanded region at different temperatures using Brewster angle microscopy (BAM). The film texture with network patterns of the complex (C18)2 Eu(DBM)4 and hs evolution with time and temperature of the subphase were examined. The average linear cell dimension and the polygon areas have been analyzed as a function of time and the temperature. The mechanism of the domain growth is qualitatively discussed. 相似文献
126.
Chiral macrocyclic amine 2 was found to be useful as an NMR chiral shift reagent for the determination of the enantiomeric purity and absolute configurations of several kinds of carboxylic acid and amino acid derivatives. 相似文献
127.
Masakazu Nakanishi Tomoko Ogi Yoshio Fukuda 《Journal of Thermal Analysis and Calorimetry》2010,101(1):391-396
We modified a commercially available thermogravimetric analyzer to introduce helium alone or with steam, oxygen or both, atmosphere
of which was controllable to be similar to that in a fixed-bed or an entrained-flow type gasifier, for studying basic properties
of biomass gasification. We also connected it to a gas chromatograph-mass selective detector for identifying materials produced
during the thermogravimetric analyses. Thermogravimetric analyses of Japanese cedar wood and identifications of the produced
materials at around 365 °C were measured as demonstrations. 相似文献
128.
Atula S.D. Sandanayaka Hisahiro Sasabe Toshikazu Takata Osamu Ito 《Journal of Photochemistry and Photobiology, C: Photochemistry Reviews》2010,11(2-3):73-92
The photosensitized electron-transfer processes in the rotaxane hybrids composed with electron-accepting fullerenes and various electron-donors placed in the rotaxanes are revealed with time-resolved fluorescence and absorption spectral methods. Porphyrins are most useful as light-harvesting donors and photosensitizing donors. In addition, aromatic amines and ferrocene act as electron-donor and also hole-shifting reagents in multi-component rotaxanes. In the rotaxanes with spatially placed donor-acceptor molecules, the role of triplet states becomes important compared with the covalently connected donor–acceptor molecular systems, which may be related to the “through-space” and “through-bond” electron transfer, respectively. In the designed multi-component rotaxanes which maintain mechanically or topologically the electron-acceptor, electron-donor, and hole-shifter, the photoinduced electron transfer, hole-shift, electron–hole recombination are established. As a whole, contribution of the triplet excited states is prominent compared with the covalently bonded molecules and supramolecular systems constructed with coordination bonds. 相似文献
129.
T. Katsumata H. Okada T. Kikuta T. Fukuda 《Applied Physics A: Materials Science & Processing》1987,42(2):103-109
The wavelength dependence and polarization characteristics of the infrared light scattered from an undoped GaAs crystal were investigated in the 90° angle infrared light scattering configuration. The scattering is Rayleigh scattering from scatterers which are always associated with the dislocations, and they are classified into three types,S, L
A
, andL
G
scatterers, according to their polarization characteristics. TheS, L
A
, andL
G
-scatterers are thought to be small As clusters, large As precipitates and large Ga precipitates, respectively. 相似文献
130.
Shigetaka Fukuda 《代数通讯》2013,41(10):3265-3268