全文获取类型
收费全文 | 217165篇 |
免费 | 2603篇 |
国内免费 | 727篇 |
专业分类
化学 | 110901篇 |
晶体学 | 3218篇 |
力学 | 9589篇 |
综合类 | 6篇 |
数学 | 25312篇 |
物理学 | 71469篇 |
出版年
2021年 | 1952篇 |
2020年 | 2167篇 |
2019年 | 2457篇 |
2018年 | 3047篇 |
2017年 | 2871篇 |
2016年 | 4312篇 |
2015年 | 2824篇 |
2014年 | 4115篇 |
2013年 | 9935篇 |
2012年 | 8216篇 |
2011年 | 9885篇 |
2010年 | 6674篇 |
2009年 | 6420篇 |
2008年 | 8726篇 |
2007年 | 8828篇 |
2006年 | 8486篇 |
2005年 | 7583篇 |
2004年 | 6978篇 |
2003年 | 6065篇 |
2002年 | 5886篇 |
2001年 | 6636篇 |
2000年 | 5089篇 |
1999年 | 3962篇 |
1998年 | 3185篇 |
1997年 | 3187篇 |
1996年 | 2939篇 |
1995年 | 2747篇 |
1994年 | 2568篇 |
1993年 | 2436篇 |
1992年 | 2764篇 |
1991年 | 2739篇 |
1990年 | 2663篇 |
1989年 | 2436篇 |
1988年 | 2488篇 |
1987年 | 2494篇 |
1986年 | 2322篇 |
1985年 | 3025篇 |
1984年 | 3268篇 |
1983年 | 2660篇 |
1982年 | 2853篇 |
1981年 | 2755篇 |
1980年 | 2630篇 |
1979年 | 2732篇 |
1978年 | 2818篇 |
1977年 | 2844篇 |
1976年 | 2900篇 |
1975年 | 2671篇 |
1974年 | 2656篇 |
1973年 | 2780篇 |
1972年 | 1752篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Kinetics and Catalysis - A series of Cu-SSZ-13@CeO2 catalysts with surface modification with CeO2 was prepared by the modified self-resemble method based on the one-pot synthesized Cu-SSZ-13... 相似文献
92.
93.
Sh. M. Khaliullin V. D. Zhuravlev V. G. Bamburov L. V. Ermakova 《Physics of Atomic Nuclei》2015,78(12):1382-1388
Submicron CaZrO3 powder is obtained in combustion reactions (solution combustion synthesis—SCS) with glycine. It is found that SCS reduces the sintering temperature of CaZrO3 powders. The dielectric properties of calcium zirconate ceramics are studied by the electrochemical impedance method. It is shown that a ceramics of powders obtained by the SCS method has high dielectric characteristics. 相似文献
94.
95.
96.
97.
Tereshchenko E. D. Cherniakov S. M. Yurik R. Yu. Rietveld M. T. Häggström I. 《Radiophysics and Quantum Electronics》2020,62(10):667-676
Radiophysics and Quantum Electronics - We present the results of comparing the total electron content measurements based on GLONASS satellite signals and the EISCAT UHF incoherent scatter radar... 相似文献
98.
Driven and non-equilibrium quantum states of matter have attracted growing interest in both theoretical and experimental studies in condensed matter physics. Recent progress in realizing transient collective states in driven or pumped Dirac materials (DMs) is reviewed herein. In particular, the focus is on optically pumped DMs which are a promising platform for transient excitonic instabilities. Optical pumping combined with the linear (Dirac) dispersion of the electronic spectrum offers a knob for tuning the effective interaction between the photoexcited electrons and holes, and thus provides a way of reducing the critical coupling for excitonic instability. As a result, a transient excitonic condensate could be achieved in a pumped DM while it is not feasible in equilibrium. A unifying theoretical framework is provided for describing transient collective states in 2D and 3D DMs. The experimental signatures are described and numerical estimates of the size of the dynamically induced excitonic gaps and the values of the critical temperatures for several specific systems, are summarized. In addition, general guidelines for identifying promising material candidates are discussed. Finally, comments are provided regarding recent experimental efforts in realizing transient excitonic condensate in pumped DMs, and outstanding issues and possible future directions are outlined. 相似文献
99.
Facile non‐lithographic route to highly aligned silica nanopatterns using unidirectionally aligned polystyrene‐block‐polydimethylsiloxane films 下载免费PDF全文
Zhe Qiang Maurice L. Wadley Bryan D. Vogt Kevin A. Cavicchi 《Journal of Polymer Science.Polymer Physics》2015,53(15):1058-1064
Thin films (monolayer and bilayer) of cylinder forming polystyrene‐block‐polydimethylsiloxane (PS‐b‐PDMS) were shear aligned by the swelling and deswelling of a crosslinked PDMS pad that was physically adhered to the film during solvent vapor annealing. The nanostructures formed by self‐assembly were exposed to ultraviolet‐ozone to partially oxidize the PDMS, followed by calcination in air at 500 °C. In this process, the PS segments were fully decomposed, while the PDMS yielded silica nanostructures. The highly aligned PDMS cylinders were thus deposited as silica nanolines on the silicon substrate. Using a bilayer film, the center‐to‐center distance of these features were effectively halved from 38 to 19 nm. Similarly, by sequential shear‐alignment of two distinct layers, a rhombic array of silica nanolines was fabricated. This methodology provides a facile route to fabricating complex topographically patterned nanostructures. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1058–1064 相似文献