全文获取类型
收费全文 | 488652篇 |
免费 | 6397篇 |
国内免费 | 1827篇 |
专业分类
化学 | 265072篇 |
晶体学 | 6005篇 |
力学 | 20520篇 |
综合类 | 9篇 |
数学 | 59360篇 |
物理学 | 145910篇 |
出版年
2020年 | 3451篇 |
2019年 | 3667篇 |
2018年 | 4124篇 |
2017年 | 3964篇 |
2016年 | 7087篇 |
2015年 | 5311篇 |
2014年 | 7575篇 |
2013年 | 22673篇 |
2012年 | 16733篇 |
2011年 | 20871篇 |
2010年 | 13259篇 |
2009年 | 13198篇 |
2008年 | 18856篇 |
2007年 | 19172篇 |
2006年 | 18207篇 |
2005年 | 16731篇 |
2004年 | 14990篇 |
2003年 | 13300篇 |
2002年 | 13025篇 |
2001年 | 14632篇 |
2000年 | 11249篇 |
1999年 | 8987篇 |
1998年 | 7378篇 |
1997年 | 7221篇 |
1996年 | 7066篇 |
1995年 | 6516篇 |
1994年 | 6193篇 |
1993年 | 6063篇 |
1992年 | 6539篇 |
1991年 | 6472篇 |
1990年 | 6046篇 |
1989年 | 5898篇 |
1988年 | 6140篇 |
1987年 | 5799篇 |
1986年 | 5621篇 |
1985年 | 8052篇 |
1984年 | 8257篇 |
1983年 | 6718篇 |
1982年 | 7352篇 |
1981年 | 7254篇 |
1980年 | 7003篇 |
1979年 | 7117篇 |
1978年 | 7360篇 |
1977年 | 7202篇 |
1976年 | 7293篇 |
1975年 | 6861篇 |
1974年 | 6840篇 |
1973年 | 7189篇 |
1972年 | 4320篇 |
1971年 | 3233篇 |
排序方式: 共有10000条查询结果,搜索用时 390 毫秒
91.
92.
Inside Cover: Ru‐Catalysed CH Arylation of Indoles and Pyrroles with Boronic Acids: Scope and Mechanistic Studies (Chem. Eur. J. 14/2015) 下载免费PDF全文
93.
R. Grosseuvres A. Comandini A. Bentaib N. Chaumeix 《Proceedings of the Combustion Institute》2019,37(2):1537-1546
The present work reports new experimental and numerical results of the combustion properties of hydrogen based mixtures diluted by nitrogen and steam. Spherical expanding flames have been studied in a spherical bomb over a large domain of equivalence ratios, initial temperatures and dilutions at an initial pressure of 100 kPa (Tini = 296, 363, 413 K; N2/O2 = 3.76, 5.67, 9; %Steam = 0, 20, 30). From these experiments, the laminar flame speed , the Markstein length L’, the activation energy Ea and the Zel'dovich β number have been determined. These parameters were also simulated using COSILAB® in order to verify the validity of the Mével et al. [1] detailed kinetic mechanism. Other parameters as the laminar flame thickness δ and the effective Lewis number Leeff were also simulated. These new results aim at providing an extended database that will be very useful in the hydrogen combustion hazard assessment for nuclear reactor power plant new design. 相似文献
94.
95.
96.
97.
Cover Picture: Coordination Chemistry of N‐Heterocyclic Nitrenium‐Based Ligands (Chem. Eur. J. 19/2015) 下载免费PDF全文
98.
Mariam Hakami Dr. Geetanjali Deokar Jasmin Smajic Dr. Nitin M. Batra Prof. Pedro M. F. J. Costa 《化学:亚洲杂志》2021,16(11):1466-1474
In the last decade, catalytic chemical vapor deposition (CVD) has been intensively explored for the growth of single-layer graphene (SLG). Despite the scattering of guidelines and procedures, variables such as the surface texture/chemistry of catalyst metal foils, carbon feedstock, and growth process parameters have been well-scrutinized. Still, questions remain on how best to standardize the growth procedure. The possible correlation of procedures between different CVD setups is an example. Here, two thermal CVD reactors were explored to grow graphene on Cu foil. The design of these setups was entirely distinct, one being a “showerhead” cold-wall type, whereas the other represented the popular “tubular” hot-wall type. Upon standardizing the Cu foil surface, it was possible to develop a procedure for cm2-scale SLG growth that differed only by the carrier gas flow rate used in the two reactors. 相似文献
99.
Dinesh R. Hussain S. Imran Roseline A. Ameelia Kalaiselvam S. 《Journal of Thermal Analysis and Calorimetry》2021,145(6):2935-2949
Journal of Thermal Analysis and Calorimetry - In this paper, the variation of thermophysical properties such as the thermal conductivity, thermal energy storage capacity, viscosity, and phase... 相似文献
100.
Herrasti P. Mazarío E. Recio Francisco J. 《Journal of Solid State Electrochemistry》2021,25(1):231-236
Journal of Solid State Electrochemistry - In this work, the use of neodymium electrodes as a basis for the immobilization of magnetite nanoparticles has been carried out. The sensitivity and... 相似文献