全文获取类型
收费全文 | 1044篇 |
免费 | 35篇 |
国内免费 | 3篇 |
专业分类
化学 | 798篇 |
晶体学 | 8篇 |
力学 | 18篇 |
数学 | 30篇 |
物理学 | 228篇 |
出版年
2021年 | 12篇 |
2019年 | 15篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 24篇 |
2015年 | 27篇 |
2014年 | 15篇 |
2013年 | 53篇 |
2012年 | 48篇 |
2011年 | 64篇 |
2010年 | 28篇 |
2009年 | 33篇 |
2008年 | 65篇 |
2007年 | 38篇 |
2006年 | 50篇 |
2005年 | 45篇 |
2004年 | 41篇 |
2003年 | 45篇 |
2002年 | 37篇 |
2001年 | 29篇 |
2000年 | 21篇 |
1999年 | 15篇 |
1998年 | 9篇 |
1997年 | 14篇 |
1996年 | 10篇 |
1995年 | 13篇 |
1994年 | 16篇 |
1993年 | 14篇 |
1992年 | 16篇 |
1991年 | 8篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 12篇 |
1986年 | 6篇 |
1985年 | 19篇 |
1984年 | 14篇 |
1983年 | 15篇 |
1982年 | 13篇 |
1981年 | 13篇 |
1980年 | 16篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1977年 | 9篇 |
1976年 | 17篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1973年 | 11篇 |
1970年 | 7篇 |
1968年 | 6篇 |
排序方式: 共有1082条查询结果,搜索用时 31 毫秒
81.
Matsumoto T Kominami T Ueda K Sugimoto T Tada T Noguchi S Yoshino H Murata K Shiro M Negishi E Toyota N Endo S Takahashi K 《Inorganic chemistry》2002,41(18):4763-4769
The 2:1 charge-transfer (CT) salts (1(2).FeBr(4) and 1(2).GaBr(4)) of ethylenedithiotetrathiafulvalenoquinone-1,3-dithiolemethide (1) with FeBr(4)(-) and GaBr(4)(-) counteranions were obtained as needle crystals, whose structures are almost the same as each other. The 1 molecules form a one dimensionally stacked column with alternation of their molecular axis direction, while the counteranions are aligned in parallel with the 1-stacked columns with the direction of their distorted-tetrahedral geometry maintained. The room-temperature electrical conductivities measured on the single crystals of 1(2).FeBr(4) and 1(2).GaBr(4) were 4.6 and 2.1 S cm(-1), respectively. From the temperature dependences of their electrical conductivities in both cases the electrical conducting properties were metallic between ca. 170 and 300 K, but below ca. 170 K converted to be semiconducting and continued till 5 K, although the activation energies are very small (4-10 meV). For 1(2).FeBr(4) very weak and antiferromagnetic interaction occurred between the d spins of FeBr(4)(-) ions in the temperature range of ca. 1-300 K. However, below ca. 15 K the ferromagnetic interaction was reversely preferential possibly by participation of the pi spin of 1. 相似文献
82.
Watanabe S Sonobe M Arai M Tazume Y Matsuo T Nakamura T Yoshida K 《Chemical communications (Cambridge, England)》2002,(23):2866-2867
A gold nanoparticle surface-modified with amide ligands shows enhanced optical sensing of anions: the detection limit is increased by about three orders of magnitude higher than that originally expected from the anion binding ability of neutral amide ligands. 相似文献
83.
84.
T. Matsuo T. Maekawa A. Inaba O. Yamamuro M. Ohama M. Ichikawa T. Tsuchida 《Journal of Molecular Structure》2006,790(1-3):129
The heat capacities of HCrO2 and DCrO2 have been measured at temperatures between 5 and 360 K. A lambda anomaly occurred at 320 K for DCrO2 but not for HCrO2. Infrared spectra were recorded at temperatures between 5 and 405 K. The spectrum of DCrO2 changed at 320 K with respect to the peak wave-number and splitting of some of the vibrations, while those of HCrO2 depended smoothly on temperature. These experimental results are discussed in terms of a deuteration-induced phase transition. 相似文献
85.
S. Juodkazis H. Okuno N. Kujime S. Matsuo H. Misawa 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1555-1559
We report on the ablation and hole drilling in stainless steel SUS304 and Si by femtosecond pulses (wavelength 800 nm; pulse duration >80 fs) at the room and low (5 Torr) air pressure ambient. It was found that the quality of surface processing is improved at low pressure avoiding debris formation. The improvement is due to suppression of the conical emission, resulting from the air optical breakdown at a pre-surface area of sample. Debris-free processing of the movable Si-MEMS components is demonstrated. Techniques for the precise measurement of focal spot size and pulse duration are discussed. PACS 87.80.Mj; 78.66.Bz; 42.62.Cf; 61.82.Bg; 61.80.-x 相似文献
86.
Hirokazu Tanaka Keizo Yoshida Yoshikuni Itoh Hiroshi Imanaka 《Tetrahedron letters》1981,22(35):3421-3422
The structure elucidation and synthesis of WS-1228 A, produced by , were described. 相似文献
87.
88.
The absorption bands arising from overtones of the CH stretching vibration of liquid benzene were measured up to the v = 0–9 transition. The transition energies at the band maxima are expressed by a cubic equation. Their bandwidths and oscillator strengths are discussed. 相似文献
89.
The heat capacity of thallium dihydrogen phosphate was measured from 12 to 300 K. A lambda anomaly with a small first order discontinuity was found at 229.76 K with the integrated enthalpy and entropy changes equal to 370 J mol-1 and 1.8 J K-1 mol-1, respectively. The entropy discontinuity at the first order transition is 0.25 J K-1 mol-1. The Landau theory of phase transitions of the second kind reproduces closely the temperature dependence of the anomalous heat capacity. This, together with the small discontinuity in the entropy, implies that the phase transition is close to a classical critical point of higher order. The relative dielectric permittivity ?r(b) along the b-axis at 1 kHz is anomalously large and strongly temperature dependent, while the ?r(a1) and ?r(c) are not. A broad absorption centered at 1700 cm-1 was observed in the infrared absorption spectrum, indicating presence of hydrogen bonding of the length ~ 0.25 nm. Occurrence of a phase transition at 127 ± 2 K was suggested by differential thermal analysis of thallium dideuterium phosphate. 相似文献
90.
H.?SegawaEmail author S.?Matsuo H.?Misawa 《Applied Physics A: Materials Science & Processing》2004,79(3):407-409
Surface corrugation has been photo-induced in a single-step process in hybrid sol-gel thin films. A model based on elastic deformation under photo-induced stress is developed to explain relief formation in this material. Computation is carried out with finite-element software. Theoretical and experimental values of relief amplitude variation with film thickness and grating period agree for small deformations. Mass transfer from illuminated to non-illuminated areas has to be associated with the elastic model to account for surface corrugation in the case of large photo-induced deformation. A comparison with a fluid mechanics model is presented. PACS 81.65.C; 81.20.F; 81.40.L 相似文献