全文获取类型
收费全文 | 3059篇 |
免费 | 114篇 |
国内免费 | 256篇 |
专业分类
化学 | 2482篇 |
晶体学 | 14篇 |
力学 | 14篇 |
综合类 | 5篇 |
数学 | 4篇 |
物理学 | 910篇 |
出版年
2024年 | 7篇 |
2023年 | 77篇 |
2022年 | 27篇 |
2021年 | 45篇 |
2020年 | 47篇 |
2019年 | 45篇 |
2018年 | 33篇 |
2017年 | 36篇 |
2016年 | 79篇 |
2015年 | 57篇 |
2014年 | 75篇 |
2013年 | 184篇 |
2012年 | 199篇 |
2011年 | 222篇 |
2010年 | 138篇 |
2009年 | 210篇 |
2008年 | 191篇 |
2007年 | 196篇 |
2006年 | 226篇 |
2005年 | 187篇 |
2004年 | 145篇 |
2003年 | 155篇 |
2002年 | 91篇 |
2001年 | 81篇 |
2000年 | 68篇 |
1999年 | 64篇 |
1998年 | 81篇 |
1997年 | 56篇 |
1996年 | 45篇 |
1995年 | 37篇 |
1994年 | 41篇 |
1993年 | 44篇 |
1992年 | 26篇 |
1991年 | 44篇 |
1990年 | 33篇 |
1989年 | 28篇 |
1988年 | 18篇 |
1987年 | 18篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 11篇 |
1978年 | 4篇 |
1976年 | 5篇 |
1974年 | 4篇 |
1973年 | 2篇 |
排序方式: 共有3429条查询结果,搜索用时 15 毫秒
91.
The kinetics of ion exchange between Ca2 , Mg2 , Co(Ⅱ), Cu(Ⅱ),Ni(Ⅱ), Fe(Ⅲ), y3 or Sm3 , respectively, in 0.50 mol/L HC1 and H on macrorecticular sulfonic ion exchange resin and the kinetics of the same reactions (M -H exchange) when Mn(Ⅱ) coexisted in resin phase as accelerating ion were studied. The accelerating effect manifested and its rule are consistent with the accelerating effect theory based on the concept concerned with adsorption electrical double layer which has been suggested in a previous paper published. 相似文献
92.
93.
气相二茂铁双电荷离子的动能谱研究 总被引:1,自引:0,他引:1
The unimolecular charge separation reactions of the doubly charged ions FeC_(10)H_(10)~(2+)、FeC_(10)H_9~(2+)、FeC_(10)H_8~(2+) produced in the ion source by electron impact from ferrocene have been studied using Mass analyzed Ion Kinetic Energy Spectrometry (MIKES) technique. From the values of the kinetic energy releases (T), the intercharge distances (R) of the exploding doubly charged ions in their transition structures have been estimated and some structural informations about the transition states can be obtained. The collision induced reactions of the FeC_(10)H_(10)~(2+) ion with Ar have been studied using MIKES, we postulate a new type of continuing reaction which may be "collisional charge separation induced dissociation". 相似文献
94.
95.
96.
Keith B. Oldham Terence J. Cardwell Jose H. Santos Alan M. Bond 《Journal of Electroanalytical Chemistry》1997,430(1-2)
Voltammetric studies in solutions of high resistivity are facilitated by the use of microelectrodes under steady-state conditions. Such solutions are encountered with solvents of low permittivity because of the very sparing solubility of electrolytes. Moreover, in such media the supporting electrolyte, as well as the electroactive ionic species, is usually extensively ion paired. Here we predict the limiting current that will flow in these circumstances, when a monovalent ion undergoes a one-electron transfer at a hemispherical microelectrode to form a neutral product. The ion pairing equilibria are assumed to be fast but all diffusion coefficients are treated as distinct. An analytical solution is elusive in the general case, but a simple numerical procedure allows the limiting current to be predicted for any combination of the system parameters. Several special cases are also discussed, some of which yield explicit formulae for the limiting current. In a companion paper, experimental data are compared with the theoretical predictions. 相似文献
97.
本文研究了具有特殊结构的氢硼酸金属有机络合物的反相色谱及机理。在MicropakC_(18)柱上,加入含离子试剂的甲醇-水作为流动相,通过用电导法测定流动相电性能,Break-through法测定离子试剂在固定相上的吸附量及制备色谱法研究各流分组成,认为此类化合物的保留机理为动态离子交换过程。 相似文献
98.
John A. McLean Brandon T. Ruotolo Kent J. Gillig David H. Russell 《International journal of mass spectrometry》2005,240(3):301
Matrix-assisted laser desorption/ionization (MALDI) coupled with ion mobility–mass spectrometry (IM–MS) provides a rapid (μs–ms) means for the two-dimensional (2D) separation of complex biological samples (e.g., peptides, oligonucleotides, glycoconjugates, lipids, etc.), elucidation of solvent-free secondary structural elements (e.g., helices, β-hairpins, random coils, etc.), rapid identification of post-translational modifications (e.g., phosphorylation, glycosylation, etc.) or ligation of small molecules, and simultaneous and comprehensive sequencing information of biopolymers. In IM–MS, protein-identification information is complemented by structural characterization data, which is difficult to obtain using conventional proteomic techniques. New avenues for enhancing the figures of merit (e.g., sensitivity, limits of detection, dynamic range, and analyte selectivity) and optimizing IM–MS experimental parameters are described in the context of deriving new information at the forefront of proteomics research. 相似文献
99.
100.