全文获取类型
收费全文 | 3144篇 |
免费 | 76篇 |
国内免费 | 7篇 |
专业分类
化学 | 1928篇 |
晶体学 | 70篇 |
力学 | 86篇 |
数学 | 589篇 |
物理学 | 554篇 |
出版年
2023年 | 10篇 |
2022年 | 92篇 |
2021年 | 116篇 |
2020年 | 52篇 |
2019年 | 56篇 |
2018年 | 76篇 |
2017年 | 62篇 |
2016年 | 114篇 |
2015年 | 99篇 |
2014年 | 120篇 |
2013年 | 235篇 |
2012年 | 188篇 |
2011年 | 201篇 |
2010年 | 162篇 |
2009年 | 135篇 |
2008年 | 173篇 |
2007年 | 140篇 |
2006年 | 130篇 |
2005年 | 115篇 |
2004年 | 100篇 |
2003年 | 84篇 |
2002年 | 63篇 |
2001年 | 34篇 |
2000年 | 37篇 |
1999年 | 21篇 |
1998年 | 25篇 |
1997年 | 24篇 |
1996年 | 32篇 |
1995年 | 25篇 |
1994年 | 21篇 |
1993年 | 16篇 |
1992年 | 25篇 |
1991年 | 28篇 |
1990年 | 37篇 |
1989年 | 30篇 |
1988年 | 19篇 |
1987年 | 22篇 |
1986年 | 22篇 |
1985年 | 44篇 |
1984年 | 37篇 |
1983年 | 23篇 |
1982年 | 17篇 |
1981年 | 21篇 |
1980年 | 17篇 |
1979年 | 24篇 |
1978年 | 14篇 |
1977年 | 14篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1974年 | 8篇 |
排序方式: 共有3227条查询结果,搜索用时 15 毫秒
1.
Rutkowski Paweł Klimczyk Piotr Jaworska Lucyna Stobierski Ludosław Dubiel Aleksandra 《Journal of Thermal Analysis and Calorimetry》2015,122(1):105-114
Journal of Thermal Analysis and Calorimetry - The work concerns the alumina–graphene materials sintered by two different pressure methods. The different particle sizes of graphene were used.... 相似文献
2.
3.
Teresa uczak Radosaw Pankiewicz Bogusawa ska Grzegorz Schroeder Maria Betowska-Brzezinska Bogumil Brzezinski 《Journal of Molecular Structure》2006,800(1-3):140-145
Novel self-assembled monolayers were obtained on silver using 4,7-diazaheptyl-trimethoxy-silane (SiN) and vinyl-trialkoxy-silane (SiVA, where the alkyl group is 3,6,9,12,15,18,21,24,27,30,33,36,39,42,45,48,51,54,57,60-eicozaoxa- hexaheptaconan). It was shown that thus modified metal surface was protected against electrooxidation. A densely packed monolayer remained stable and did not desorb from the Ag electrode on the potential cycling. The structure of SiN and SiVA as well as their complexes with Li+ cations were calculated and visualised by the AM1d and PM5 semi-empirical methods. 相似文献
4.
Jacek Doskocz Jadwiga Sołoducho Joanna Cabaj Mieczysław Łapkowski Sylwia Golba Krystyna Palewska 《Electroanalysis》2007,19(13):1394-1401
A convenient and higher yielding synthetic route to N‐alkyl‐bis(thiophene)phenothiazine derivatives is reported and their aggregation, electrochemical properties and polymerization are characterized. The key step in the synthesis of this group of compounds has been the Stille type coupling reaction between the N‐alkyldibromophenothiazine and tin derivatives of thiophene as the best way for preparation of conjugated N‐alkylphenothiazine derivatives. For this group of compounds we also present an electrochemical polymerization effect and widely adopted approach to prepare structurally ordered thin, electroconducting films by Langmuir–Blodgett technique. 相似文献
5.
Tadeusz Biedro Przemysaw Kubisa 《Journal of polymer science. Part A, Polymer chemistry》2004,42(13):3230-3235
The cationic polymerization of styrene in a neutral ionic liquid, 1‐butyl‐3‐methylimidazolium hexafluorophosphate, with a 1‐phenetyl chloride/TiCl4 initiating system is reported. The polymerization proceeds to a high conversion, but an analysis of the matrix‐assisted laser desorption/ionization time‐of‐flight spectra of the polymers indicates that chain transfer is significant, leading to a lack of control over the molecular weight and molecular weight distribution. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3230–3235, 2004 相似文献
6.
Sajewicz Mieczysław Hauck Heinz-E. Drabik Gabriela Namysło Ewa Głód Bronisław Kowalska Teresa 《平面色谱法杂志一现代薄层色谱法》2006,19(4):278-281
JPC – Journal of Planar Chromatography – Modern TLC - We have previously described unexpected two-dimensionality in the thin-layer chromatographic separation of pairs of enantiomers of... 相似文献
7.
A mistake concerning the ultra LI-ideal of a lattice implication algebra is pointed out, and some new sufficient and necessary conditions for an LI-ideal to be an ultra LI-ideal are given. Moreover, the notion of an LI-ideal is extended to MTL-algebras, the notions of a (prime, ultra, obstinate, Boolean) LI-ideal and an ILI-ideal of an MTL-algebra are introduced, some important examples are given, and the following notions are proved to be equivalent in MTL-algebra: (1) prime proper LI-ideal and Boolean LI-ideal, (2) prime proper LI-ideal and ILI-ideal, (3) proper obstinate LI-ideal, (4) ultra LI-ideal.
This work was supported by the Zhejiang Provincial Natural Science Foundation of China (Grant No. Y605389) and K. C. Wong
Magna Fund in Ningbo University. 相似文献
8.
Zdzisław Denkowski Leszek Gasiński Nikolaos S. Papageorgiou 《Journal of Global Optimization》2006,34(3):317-337
We study a resonant semilinear elliptic hemivariational inequality. Under some assumptions of strong resonance on the Clarke
subdifferential of the superpotential, and using nonsmooth critical point theory, the existence of a nontrivial solution of
the problem is shown.
This paper has been partially supported by the State Committee for Scientific Research of Poland (KBN) under research grants
no. 2 P03A 003 25 and no. 4 T07A 027 26. 相似文献
9.
10.
The existence of sparse pseudorandom distributions is proved. These are probability distributions concentrated in a very small set of strings, yet it is infeasible for any polynomial-time algorithm to distinguish between truly random coins and coins selected according to these distributions. It is shown that such distributions can be generated by (nonpolynomial) probabilistic algorithms, while probabilistic polynomial-time algorithms cannot even approximate all the pseudorandom distributions. Moreover, we show the existence of evasive pseudorandom distributions which are not only sparse, but also have the property that no polynomial-time algorithm may find an element in their support, except for a negligible probability. All these results are proved independently of any intractability assumption. 相似文献