全文获取类型
收费全文 | 8332篇 |
免费 | 1330篇 |
国内免费 | 1266篇 |
专业分类
化学 | 6118篇 |
晶体学 | 90篇 |
力学 | 662篇 |
综合类 | 95篇 |
数学 | 1135篇 |
物理学 | 2828篇 |
出版年
2024年 | 7篇 |
2023年 | 161篇 |
2022年 | 137篇 |
2021年 | 232篇 |
2020年 | 316篇 |
2019年 | 304篇 |
2018年 | 231篇 |
2017年 | 247篇 |
2016年 | 421篇 |
2015年 | 339篇 |
2014年 | 431篇 |
2013年 | 584篇 |
2012年 | 722篇 |
2011年 | 694篇 |
2010年 | 567篇 |
2009年 | 481篇 |
2008年 | 537篇 |
2007年 | 452篇 |
2006年 | 448篇 |
2005年 | 432篇 |
2004年 | 361篇 |
2003年 | 336篇 |
2002年 | 388篇 |
2001年 | 357篇 |
2000年 | 250篇 |
1999年 | 238篇 |
1998年 | 180篇 |
1997年 | 171篇 |
1996年 | 184篇 |
1995年 | 143篇 |
1994年 | 129篇 |
1993年 | 94篇 |
1992年 | 68篇 |
1991年 | 68篇 |
1990年 | 43篇 |
1989年 | 26篇 |
1988年 | 32篇 |
1987年 | 18篇 |
1986年 | 28篇 |
1985年 | 20篇 |
1984年 | 9篇 |
1983年 | 14篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1974年 | 1篇 |
1957年 | 3篇 |
1936年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Zhong Weizhou Zhang Zexiong Chen Xiaowei Wei Qiang Chen Gang Huang Xicheng 《Acta Mechanica Sinica》2021,37(7):1136-1151
Acta Mechanica Sinica - Multi-scale finite element method is adopted to simulate wood compression behavior under axial and transverse loading. Representative volume elements (RVE) of wood... 相似文献
2.
Interactions of the vector breathers for the coupled Hirota system with $$4\times 4$$ 4 × 4 Lax pair
Nonlinear Dynamics - In this paper, we investigate the interactions of the vector breathers for the coupled Hirota system with $$4\times 4$$ Lax pair. Firstly, we give the first-order breather... 相似文献
3.
Science China Mathematics - In this paper, we obtain a necessary and sufficient condition for a U(n)-invariant complex Finsler metric F on domains in ?n to be strongly convex, which also... 相似文献
4.
5.
Yuan Xin Zhang Shuren Zhong Xuanmeng Yuan Hao Song Dongfan Wang Xiaoyu Yu Hanyang Guo Zijian 《中国科学:化学(英文版)》2022,65(10):1978-1984
Science China Chemistry - Oncogenic KRAS reprograms pancreatic ductal adenocarcinoma (PDAC) cells to a state that is awfully resistant to apoptosis. An alternative coping strategy is to trigger a... 相似文献
6.
Nonlinear Dynamics - In this work, the problem of hybrid control strategy for delayed neural networks is investigated via an impulsive-based bilateral looped-functional (IBBLF) approach. Firstly, a... 相似文献
7.
Dr. Rong-Lin Zhong Dr. Feng-Wei Gao Dr. Hong-Liang Xu Prof. Zhong-Min Su 《Chemphyschem》2019,20(14):1879-1884
The nature of the 2e/12c bond and its conversion to a carbon-carbon single bond in phenalenyl dimers have prompted a great deal of interests recently. In this work, we theoretically investigated a series of π-stacking phenalenyl derivatives with 2e/12c bonding character by density functional theory (DFT) calculations to elucidate origin of this unusual bond conversion. Results show that bond-conversion of the phenalenyl dimer easily occurs at room-temperature both dynamically and thermodynamically. However, bond-conversion of hetero π-stacking adducts, in which the two center carbon atoms were substituted by boron and nitrogen atoms, respectively, is much more difficult, because the 2e/12c bond is stabilized by its charge transfer character. Consequently, the bond-conversion is an endothermic process, albeit with a low conversion barrier. Interestingly, Lewis acid-base interactions would be induced by substitution of the center nitrogen atom to phosphorus atom. The 2e/12c bond is further stabilized by 5.9 kcal mol−1 and its conversion is also thermodynamically unfavorable. 相似文献
8.
Guangrui Chen Yuxing Yan Dr. Jie Wang Prof. Yong Sik Ok Guiyuan Zhong Prof. Bu Yuan Guan Prof. Yusuke Yamauchi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(44):19831-19836
Mesoporous core–shell nanostructures with controllable ultra-large open channels in their nanoshells are of great interest. However, soft template-directed cooperative assembly to mesoporous nanoshells with highly accessible pores larger than 30 nm, or even above 50 nm into macroporous range, remains a significant challenge. Herein we report a general approach for precisely tailored coating of hierarchically macro-/mesoporous polymer and carbon shells, possessing highly accessible radial channels with extremely wide pore size distribution from ca. 10 nm to ca. 200 nm, on diverse functional materials. This strategy creates opportunities to tailor the interfacial assembly of irregular mesostructured nanounits on core materials and generate various core–shell nanomaterials with controllable pore architectures. The obtained Fe,N-doped macro-/mesoporous carbon nanoshells show enhanced electrochemical performance for the oxygen reduction reaction in alkaline condition. 相似文献
9.
Dr. Haoxuan Li Haifei Wen Dr. Zhijun Zhang Dr. Nan Song Prof. Ryan T. K. Kwok Prof. Jacky W. Y. Lam Prof. Lei Wang Prof. Dong Wang Prof. Ben Zhong Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(46):20551-20555
Using reverse thinking of the aggregation-induced emission (AIE) principle, we demonstrate an ingenious and universal protocol for amplifying molecular motions to boost photothermal efficiency of fibers. Core–shell nanofibers having the olive oil solution of AIE-active molecules as the core surrounded by PVDF-HFP shell were constructed by coaxial electrospinning. The molecularly dissolved state of AIE-active molecules allows them to freely rotate and/or vibrate in nanofibers upon photoexcitation and thus significantly elevates the proportion of non-radiative energy dissipation, affording impressive heat-generating efficiency. Photothermal evaluation shows that the core–shell nanofibers with excellent durability can reach up to 22.36 % of photothermal conversion efficiency, which is 26-fold as the non-core–shell counterpart. Such a core–shell fiber can be used for photothermal textiles and solar steam generation induced by natural sunlight with green and carbon-zero emission. 相似文献
10.
Nonlinear Dynamics - An effective and simple method to solve nonlinear evolution partial differential equations is the self-similarity transformation, in which one utilizes solutions of the known... 相似文献