全文获取类型
收费全文 | 2022篇 |
免费 | 2篇 |
国内免费 | 11篇 |
专业分类
化学 | 1400篇 |
晶体学 | 12篇 |
力学 | 28篇 |
数学 | 340篇 |
物理学 | 255篇 |
出版年
2021年 | 7篇 |
2020年 | 14篇 |
2019年 | 7篇 |
2018年 | 13篇 |
2017年 | 9篇 |
2016年 | 13篇 |
2015年 | 11篇 |
2014年 | 21篇 |
2013年 | 106篇 |
2012年 | 81篇 |
2011年 | 97篇 |
2010年 | 71篇 |
2009年 | 42篇 |
2008年 | 104篇 |
2007年 | 105篇 |
2006年 | 124篇 |
2005年 | 132篇 |
2004年 | 116篇 |
2003年 | 97篇 |
2002年 | 80篇 |
2001年 | 16篇 |
2000年 | 21篇 |
1999年 | 21篇 |
1998年 | 20篇 |
1997年 | 32篇 |
1996年 | 33篇 |
1995年 | 16篇 |
1994年 | 35篇 |
1993年 | 32篇 |
1992年 | 15篇 |
1991年 | 21篇 |
1990年 | 23篇 |
1989年 | 19篇 |
1988年 | 21篇 |
1987年 | 18篇 |
1986年 | 16篇 |
1985年 | 31篇 |
1984年 | 33篇 |
1983年 | 15篇 |
1982年 | 53篇 |
1981年 | 40篇 |
1980年 | 37篇 |
1979年 | 34篇 |
1978年 | 30篇 |
1977年 | 37篇 |
1976年 | 25篇 |
1975年 | 19篇 |
1974年 | 19篇 |
1973年 | 13篇 |
1971年 | 8篇 |
排序方式: 共有2035条查询结果,搜索用时 15 毫秒
951.
The uptake of 2-nitrophenol, 2-methylphenol, 3-methylphenol, and 4-methylphenol on aqueous surfaces was investigated between 278 and 303 K, using the wetted-wall flow tube technique coupled with UV absorption spectroscopic detection. The uptake coefficients gamma were found to be independent of the aqueous phase composition and of the gas-liquid contact times. In addition, the uptake coefficients and the derived mass accommodation coefficients alpha show a negative temperature dependence in the temperature range studied. The mass accommodation coefficients decrease from 5.2 x 10(-3) to 8.3 x 10(-4), from 5.0 x 10(-3) to 3.1 x 10(-4), from 6.7 x 10(-3) to 7.3 x 10(-4), and from 1.2 x 10(-2) to 5.9 x 10(-4) for 2-nitrophenol, 2-methylphenol, 3-methylphenol, and 4-methylphenol, respectively. These results are used to discuss the incorporation of these species into the liquid using the nucleation theory. These data combined with the Henry's law constants were used to estimate the partitioning of the phenolic compounds between gaseous and aqueous phases and the corresponding atmospheric lifetimes under clear sky (tau(gas)) and cloudy conditions (tau(multiphase)) have then been derived. 相似文献
952.
Catala L Mathonière C Gloter A Stephan O Gacoin T Boilot JP Mallah T 《Chemical communications (Cambridge, England)》2005,(6):746-748
Nanorods of the photomagnetic coordination network Mo(CN)8Cu2 coated with polyvinylpyrrolidone were prepared and exhibit an enhanced effect upon irradiation when compared to the bulk. 相似文献
953.
A catenane consisting of a large ring threaded through both cyclic units of a handcuff-like compound
The template effect of copper(I) allowed the preparation of a new catenane constructed around a bis-macrocyclic unit; a double ring-closing metathesis reaction afforded the central ring which is threaded through both rings of the bis-macrocycle. 相似文献
954.
955.
The usual action integral of classical electrodynamics is derived starting from Lanczos’s electrodynamics – a pure field theory in which charged particles are identified with singularities of the homogeneous Maxwell’s equations interpreted as a generalization of the Cauchy–Riemann regularity conditions from complex to biquaternion functions of four complex variables. It is shown that contrary to the usual theory based on the inhomogeneous Maxwell’s equations, in which charged particles are identified with the sources, there is no divergence in the self-interaction so that the mass is finite, and that the only approximations made in the derivation are the usual conditions required for the internal consistency of classical electrodynamics. Moreover, it is found that the radius of the boundary surface enclosing a singularity interpreted as an electron is on the same order as that of the hypothetical “bag” confining the quarks in a hadron, so that Lanczos’s electrodynamics is engaging the reconsideration of many fundamental concepts related to the nature of elementary particles. 相似文献
956.
957.
Identification of traces of chemical warfare agents (CWA) is generally performed with spectral methods such as mass spectrometry (MS) or NMR, but the use of element-specific detectors is most often required to extract interesting signals from gas chromatographic (GC) data heavily masked by natural interferents. The pulsed flame phosphorus detector (P-FPD) is able to detect phosphorus, sulphur and arsenic, and thus should be very well-suited to CWA detection. However, first results using standard operating conditions recommended by the manufacturer of P-FPD led to false positive detection of phosphorus-containing compounds on the sulphur line. Therefore, an optimisation process of the selectivity of P-FPD for phosphorus versus sulphur or arsenic was undertaken, and allowed to identify gate delay and gate width as crucial parameters for the performance of P-FPD. While selectivity could be significantly improved, unexpectedly, this resulted in a concurrent important loss of sensitivity (ca. 45%) for arsenic, which suggests that this detector should be carefully optimised with respect, and prior to its purported use. 相似文献
958.
Jean-Pierre Demailly 《Inventiones Mathematicae》1982,69(3):347-374
Sans résumé 相似文献
959.
960.
Roger Escale Ammar El Khayat Jean-Pierre Vidal Jean-Pierre Girard Jean-Claude Rossi 《Journal of heterocyclic chemistry》1984,21(4):1033-1040
A series of new homologous B-norbenzomorphans, the 3,5-methano-2,3,4,5-tetrahydro-lH-l- and 2-benzazepines inculding 7- and 8-intro or amino derivatives have been synthesized as potential CNS drugs. 相似文献