全文获取类型
收费全文 | 185805篇 |
免费 | 8365篇 |
国内免费 | 6075篇 |
专业分类
化学 | 107141篇 |
晶体学 | 2257篇 |
力学 | 8869篇 |
综合类 | 402篇 |
数学 | 19243篇 |
物理学 | 62333篇 |
出版年
2022年 | 1388篇 |
2021年 | 2192篇 |
2020年 | 2530篇 |
2019年 | 2644篇 |
2018年 | 2739篇 |
2017年 | 2751篇 |
2016年 | 4177篇 |
2015年 | 3426篇 |
2014年 | 4720篇 |
2013年 | 9195篇 |
2012年 | 8310篇 |
2011年 | 9747篇 |
2010年 | 6876篇 |
2009年 | 6953篇 |
2008年 | 8548篇 |
2007年 | 8150篇 |
2006年 | 7606篇 |
2005年 | 6758篇 |
2004年 | 5740篇 |
2003年 | 4964篇 |
2002年 | 5016篇 |
2001年 | 5243篇 |
2000年 | 4053篇 |
1999年 | 3178篇 |
1998年 | 2675篇 |
1997年 | 2541篇 |
1996年 | 2174篇 |
1995年 | 2124篇 |
1994年 | 2121篇 |
1993年 | 1886篇 |
1992年 | 2114篇 |
1991年 | 2215篇 |
1990年 | 2003篇 |
1989年 | 1960篇 |
1988年 | 1901篇 |
1987年 | 1779篇 |
1986年 | 1725篇 |
1985年 | 2201篇 |
1984年 | 2321篇 |
1983年 | 1893篇 |
1982年 | 2064篇 |
1981年 | 1950篇 |
1980年 | 1866篇 |
1979年 | 2025篇 |
1978年 | 2184篇 |
1977年 | 2061篇 |
1976年 | 2095篇 |
1975年 | 2009篇 |
1974年 | 2064篇 |
1973年 | 2048篇 |
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
61.
62.
Dr. Yogesh Kumar Maurya Dr. Pingchun Wei Takahide Shimada Dr. Kazuhisa Yamasumi Dr. Shigeki Mori Prof. Dr. Ko Furukawa Dr. Hajime Kusaba Prof. Dr. Tatsumi Ishihara Prof. Dr. Yongshu Xie Dr. Masatoshi Ishida Prof. Dr. Hiroyuki Furuta 《化学:亚洲杂志》2021,16(7):743-747
A facile synthetic strategy towards conformationally stable chiral chromophores based on dimeric porphyrinoids has been established. A peculiar class of face-to-face intramolecularly interlocked corrole dimers were formed by the oxidative C−C coupling linked at the inner carbon sites upon simple treatment of copper(II) ions. Their intrinsic electronic structures were modulated by the peripheral corrole ring annulations, which lead to distinct optical properties and redox profiles. The stereogenic carbon centers implemented in the confused corrole skeleton provided a rationale for designing novel chiral materials. 相似文献
63.
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
64.
65.
I. F. Golovnev E. I. Golovneva L. A. Merzhievsky V. M. Fomin V. E. Panin 《Physical Mesomechanics》2015,18(3):179-186
Molecular dynamics simulation was performed to study the formation of cluster structure, interfaces, and surfaces with different curvature radii in a perfect nanocrystal passed through by a nonlinear wave. It is shown that this process is a type of nanostructure self-organization in response to an external energy flux with subsequent development of a strong rotational field. 相似文献
66.
In the present research, hierarchical structure observation and mechanical property characterization for a type of biomaterial are carried out. The investigated biomaterial is Hyriopsis cumingii, a typical limnetic shell, which consists of two different structural layers, a prismatic "pillar"structure and a nacreous "brick and mortar" structure. The prismatic layer looks like a "pillar forest" with variationsection pillars sized on the order of several tens of microns.The nacreous material looks like a "brick wall" with bricks sized on the order of several microns. Both pillars and bricks are composed of nanoparticles. The mechanical properties of the hierarchical biomaterial are measured by using the nanoindentation test. Hardness and modulus are measured for both the nacre layer and the prismatic layer, respectively.The nanoindentation size effects for the hierarchical structural materials are investigated experimentally. The results show that the prismatic nanostructured material has a higher stiffness and hardness than the nacre nanostructured material.In addition, the nanoindentation size effects for the hierarchical structural materials are described theoretically, by using the trans-scale mechanics theory considering both strain gradient effect and the surface/interface effect. The modeling results are consistent with experimental ones. 相似文献
67.
Echabaane M. Hfaiedh S. Smiri B. Saidi F. Dridi C. 《Journal of Solid State Electrochemistry》2021,25(6):1797-1806
Journal of Solid State Electrochemistry - The fast and sensitive detection of copper ions would be essential for water monitoring. Herein, we report a novel development of an impedimetric sensor... 相似文献
68.
69.
Guo Yan Li Zhuang Wei Yuxi Zhang Xinxu Shi Kexin 《Journal of Solid State Electrochemistry》2022,26(4):1051-1065
Journal of Solid State Electrochemistry - Polyvinylpyrrolidone (PVP) and graphene (G)-modified iron oxides (Fe2O3-PVP-G) are prepared by a simple hydrothermal reaction. Their morphology and... 相似文献
70.
Journal of Thermal Analysis and Calorimetry - Novel porous carbon sheets were developed as green, renewable, cost-effective, and efficient flame retardant material for thermoplastic polymers.... 相似文献