全文获取类型
收费全文 | 968篇 |
免费 | 22篇 |
国内免费 | 2篇 |
专业分类
化学 | 528篇 |
晶体学 | 7篇 |
力学 | 39篇 |
数学 | 112篇 |
物理学 | 306篇 |
出版年
2023年 | 8篇 |
2022年 | 9篇 |
2021年 | 15篇 |
2020年 | 23篇 |
2019年 | 16篇 |
2018年 | 15篇 |
2017年 | 18篇 |
2016年 | 17篇 |
2015年 | 25篇 |
2014年 | 30篇 |
2013年 | 108篇 |
2012年 | 33篇 |
2011年 | 51篇 |
2010年 | 37篇 |
2009年 | 39篇 |
2008年 | 33篇 |
2007年 | 37篇 |
2006年 | 25篇 |
2005年 | 27篇 |
2004年 | 28篇 |
2003年 | 21篇 |
2002年 | 20篇 |
2001年 | 14篇 |
2000年 | 12篇 |
1999年 | 15篇 |
1998年 | 10篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 14篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 8篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 17篇 |
1984年 | 21篇 |
1983年 | 13篇 |
1982年 | 11篇 |
1981年 | 16篇 |
1980年 | 26篇 |
1979年 | 13篇 |
1978年 | 19篇 |
1977年 | 17篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1973年 | 7篇 |
1972年 | 7篇 |
排序方式: 共有992条查询结果,搜索用时 62 毫秒
281.
A complete normal coordinate analysis was performed by two different methods: a classical Wilson’s G-F matrix method and the
semi-empirical molecular orbital PM3 method, for a five coordinate tris(p-fluorophenyl)antimony di(N-phenylglycinate) [(p-FC6H4)3Sb(O2CCH2NHC6H5)2], known to be an in vitro antitumour molecule.
相似文献
282.
Stopar JD Lucey PG Sharma SK Misra AK Taylor GJ Hubble HW 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(10):2315-2323
Raman spectroscopy is a powerful technique for materials analysis, and we are developing and analyzing a remote Raman system for use on a planetary lander or rover. We have acquired data at a distance of 10m from a variety of geologic materials using different instrument designs. We have employed a pulsed laser with both an ungated detector and a gated detector. A gated detector can reduce long-lived fluorescence while still collecting all Raman signal. In order to design a flight instrument, we need to quantify how natural surfaces will respond to laser stimulus. We define remote Raman efficiency of natural surfaces as the ratio of radiant exitance leaving a natural surface to the irradiance of the incident laser. The radiant exitance of a natural surface is the product of the sample radiance, the projected solid angle, and the full-width-half-maximum of the Raman signal. We have determined the remote Raman efficiency for a variety of rocks and minerals. The best efficiencies are achieved for large, clear, single crystals that produce the most radiant exitance, while darker fine-grained mineral mixtures produce lower efficiencies. By implementing a pulsed laser, gated detector system we have improved the signal detection and have generally decreased the integration time necessary to detect Raman signal from natural surfaces. 相似文献
283.
Projectile deexcitation Lyman x-ray emission following electron capture and K excitation has been studied in collisions of bare and Li-like sulphur ions (of energy 110 MeV) with fullerenes (C(60)/C(70)) and different gaseous targets. The intensity ratios of different Lyman x-ray lines in collisions with fullerenes are found to be substantially lower than those for the gas targets, both for capture and excitation. This has been explained in terms of a model based on "solidlike" effect, namely, wakefield induced stark mixing of the excited states populated via electron capture or K excitation: a collective phenomenon of plasmon excitation in the fullerenes under the influence of heavy, highly charged ions. 相似文献
284.
Bioleaching with ultrasound 总被引:5,自引:0,他引:5
Application of bioleaching of metals in a large-scale operation is reviewed briefly. Continued technical innovation is vital for the wider utilisation of this extraction process within the mineral industries. Therefore, the use of power ultrasound in combination with bioleaching (referred to as sonobioleaching) has been studied and is shown to be beneficial in the recovery of nickel from lean grade ores. The role of ultrasound in improving the benefits and lowering the drawbacks of bioleaching to an acceptable level are described. A possible mechanism for improving and intensifying this process is hypothesised. 相似文献
285.
Non-covalent interactions between met- and leu-enkephalins and their antisense peptides were studied by electrospray ionization mass spectrometry. Mixtures of sense and antisense peptides gave both the corresponding homodimers and heterodimers. The relative abundance ratios of the heterodimer to that of the homodimer of the sense peptide and the relative stability constants of the heterodimers were compared with the corresponding values from mixtures of the sense peptides and a control peptide. The results show that there is a preferential interaction between the sense and antisense peptides compared with that between the sense and control peptides. 相似文献
286.
287.
288.
289.
We derive an expression for the Knight shift (K) including spin-orbit and many-body effects using fite temperature Green function method. We obtain a new contribution to K which is non-zero only when spin-orbit interaction is taken into account. For p-type PbTe, we find that this contribution is of the same order of magnitude as other contributions which have been considered in the past. The effect of exchange and correlation on this new contribution is discussed briefly. 相似文献
290.