全文获取类型
收费全文 | 3611篇 |
免费 | 59篇 |
国内免费 | 13篇 |
专业分类
化学 | 2464篇 |
晶体学 | 31篇 |
力学 | 58篇 |
数学 | 677篇 |
物理学 | 453篇 |
出版年
2016年 | 48篇 |
2015年 | 53篇 |
2014年 | 52篇 |
2013年 | 134篇 |
2012年 | 93篇 |
2011年 | 105篇 |
2010年 | 60篇 |
2009年 | 89篇 |
2008年 | 104篇 |
2007年 | 99篇 |
2006年 | 103篇 |
2005年 | 117篇 |
2004年 | 114篇 |
2003年 | 103篇 |
2002年 | 85篇 |
2001年 | 79篇 |
2000年 | 74篇 |
1999年 | 46篇 |
1998年 | 51篇 |
1997年 | 64篇 |
1996年 | 63篇 |
1995年 | 45篇 |
1994年 | 62篇 |
1993年 | 55篇 |
1992年 | 58篇 |
1991年 | 50篇 |
1990年 | 56篇 |
1989年 | 74篇 |
1988年 | 76篇 |
1987年 | 70篇 |
1986年 | 42篇 |
1985年 | 56篇 |
1984年 | 59篇 |
1983年 | 37篇 |
1982年 | 51篇 |
1981年 | 57篇 |
1980年 | 72篇 |
1979年 | 58篇 |
1978年 | 61篇 |
1977年 | 38篇 |
1976年 | 40篇 |
1975年 | 57篇 |
1974年 | 48篇 |
1973年 | 47篇 |
1972年 | 42篇 |
1971年 | 38篇 |
1970年 | 39篇 |
1967年 | 29篇 |
1966年 | 33篇 |
1965年 | 32篇 |
排序方式: 共有3683条查询结果,搜索用时 0 毫秒
91.
92.
93.
Na5AlF2(PO4)2: Synthesis, Crystal Structure and Ionic Conductivity Two different procedures (precipitation from aqueous solution and solid state reaction) for the synthesis of hitherto unknown Na5AlF2(PO4)2 were optimized. The crystal structure was determined using diffractometer data (P3 , a = b = 10.483(1), c = 6.607(1) Å, MoKα, 1080 independent reflections, Rw = 0.025). PO4-tetrahedra and AlO4F2-“octahedra” are connected via common vertices forming a twodimensionally extended heteropolyanion. Sodium is located in interconnected spacings of the [AlF2(PO4)2]-part of the structure. Ionic conductivity as expected because of these structural features was affirmed experimentally. 相似文献
94.
95.
96.
Wolf-Dieter Fessner Gottfried Sedelmeier Lothar Knothe Horst Prinzbach Grety Rihs Zhong-Zhi Yang Branka Kova
Edgar Heilbronner 《Helvetica chimica acta》1987,70(7):1816-1842
‘Face-to-Face’ Benzo-anellated Homologous Hypostrophenes. Syntheses, X-Ray-Structure Analyses and PE Spectra ‘Face-to-face’ Benzo-anellated homologous hypostrophenes (series M ), of interest as substrates for [6 + 6]-photocycloaddition reactions, have been synthesized. From X-ray structural analyses of 13b and 13c shortest C? C distances of 2.80(2.76)/2.71 Å and interorbital angles (ω) of 129° (128°)/130° between the benzene rings have been determined. The PE spectra are discussed in the context of transannular π,π interactions. 相似文献
97.
We studied the behaviour of Li/Li(4)Ti(5)O(12) cells by electrochemical impedance spectroscopy to gain insight into the changes at the electrode/electrolyte interfaces during extensive cycling. A simple equivalent-circuit model is able to describe the impedance of the complete battery as a function of both state-of-charge and state-of-degradation. The formation of the solid-electrolyte interface and dendrite growth at the Li metal electrode have a strong influence on the impedance measurements although the battery performance is not significantly affected. 相似文献
98.
E. Fischbach G. L. Klimchitskaya D. E. Krause V. M. Mostepanenko 《The European Physical Journal C - Particles and Fields》2010,68(1-2):223-226
We discuss the constraints on the parameters of a Yukawa interaction obtained from the indirect measurements of the Casimir pressure between parallel plates using the sphere–plate configuration. Recently, it was claimed in the literature that the application of the proximity force approximation (PFA) to the calculation of a Yukawa interaction in the sphere–plate configuration could lead to a large error of order 100% in the constraints obtained. Here we re-calculate the constraints both exactly and using the PFA, and arrive at identical results. We elucidate the reasons why an incorrect conclusion was obtained suggesting that the PFA is inapplicable to calculate the Yukawa force. 相似文献
99.
100.