全文获取类型
收费全文 | 15358篇 |
免费 | 2772篇 |
国内免费 | 2508篇 |
专业分类
化学 | 10945篇 |
晶体学 | 221篇 |
力学 | 932篇 |
综合类 | 208篇 |
数学 | 1855篇 |
物理学 | 6477篇 |
出版年
2024年 | 8篇 |
2023年 | 286篇 |
2022年 | 340篇 |
2021年 | 425篇 |
2020年 | 629篇 |
2019年 | 605篇 |
2018年 | 544篇 |
2017年 | 520篇 |
2016年 | 748篇 |
2015年 | 786篇 |
2014年 | 951篇 |
2013年 | 1191篇 |
2012年 | 1410篇 |
2011年 | 1428篇 |
2010年 | 1071篇 |
2009年 | 973篇 |
2008年 | 1157篇 |
2007年 | 1073篇 |
2006年 | 992篇 |
2005年 | 886篇 |
2004年 | 634篇 |
2003年 | 534篇 |
2002年 | 502篇 |
2001年 | 435篇 |
2000年 | 374篇 |
1999年 | 301篇 |
1998年 | 250篇 |
1997年 | 215篇 |
1996年 | 232篇 |
1995年 | 191篇 |
1994年 | 158篇 |
1993年 | 137篇 |
1992年 | 118篇 |
1991年 | 95篇 |
1990年 | 91篇 |
1989年 | 69篇 |
1988年 | 50篇 |
1987年 | 45篇 |
1986年 | 42篇 |
1985年 | 47篇 |
1984年 | 17篇 |
1983年 | 16篇 |
1982年 | 17篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1957年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
11.
Hao Sun Cunlu Dong Aijun Huang Prof. Haijuan Zhan Dr. Gang Wang Prof. Wanyi Liu Prof. Baojun Ma Prof. Wei Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(28):e202200019
Transition metal Fe, Co, Ni and Cu doped strontium titanate-rich SrTiO3@TiO2 (STO@T) materials were prepared by hydrothermal method. The prepared doped materials exhibit better photocatalytic CO2 reduction to CH4 ability under visible light conditions. Among them, Fe-doped and undoped SrTiO3@TiO2 under visible light conditions CO2 reduction products only CO, while M-STO@T (M=Co, Ni, Cu) samples converted CO2 to CH4. The average methane yield of Ni-doped STO@T samples are as high as 73.85 μmol g−1 h−1. The production of methane is mainly due to the increase in the response of the doped samples to visible light. And the increase in the separation rate of photogenerated electrons and holes and the efficiency of electron transport caused by the generation of impurity levels. The impurity level caused by Ti3+ plays an important role in the production of methane by CO2 visible light reduction. Ni doping effectively improves the photocatalytic performance of STO@T and CO2 reduction mechanism were explained. 相似文献
12.
Yang Gang Wang Yanhui Yang Xueying Pan Yuelong Liu Yu Cheng Jianfeng Jiang Qiao Tuo Xianguo 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2135-2145
Journal of Radioanalytical and Nuclear Chemistry - The preparation of C30 concrete for a cavernous waste repository under construction in China and its Cs(I) adsorption performance were... 相似文献
13.
The purpose of this paper is to investigate the connections between the weak Galerkin (WG) methods with and without stabilizers. The choices of stabilizers directly affect the convergence rates of the corresponding WG methods in general. However, we observed that the convergence rates are independent of the choices of stabilizers for these WG elements with stabilizers being optional. In this paper, we will verify such phenomena theoretically as well as numerically.
相似文献14.
15.
In this paper we derive a relative volume comparison of Ricci flow under a certain local curvature condition. It is a refinement of Perelman's no local collapsing theorem in Perelman(2002). 相似文献
16.
Russian Physics Journal - 相似文献
17.
Gang Li Libo Liao Xinchou Lou Peixun Shen Weimin Song Shudong Wang Zhaoling Zhang 《中国物理C(英文版)》2022,46(11):113001-113001-8
Various Higgs factories are proposed to study the Higgs boson precisely and systematically in a model- independent way. In this study, the Particle Flow Network and ParticleNet techniques are used to classify the Higgs decays into multicategories, and the ultimate goal is to realize an "end-to-end" analysis. A Monte Carlo simulation study is performed to demonstrate the feasibility, and the performance looks rather promising. This result could be the basis of a "one-stop" analysis to measure all the branching fractions of the Higgs decays simultaneously. 相似文献
18.
Fuzzy Optimization and Decision Making - Seepage equation in fissured porous media is a partial differential equation describing the variation of pressure of a given area over time. In traditional... 相似文献
19.
In recent years, clapping synchronization between individuals has been widely studied as one of the typical synchronization phenomena. In this paper, we aim to reveal the synchronization mechanism of clapping interactions by observing two individuals’ clapping rhythms in a series of experiments. We find that the two synchronizing clapping rhythm series exhibit long-range cross-correlations(LRCCs);that is, the interaction of clapping rhythms can be seen as a strong-anticipation process. Previous studies have demonstrated that the interactions in local timescales or global matching in statistical structures of fluctuation in long timescales can be sources of the strong-anticipation process. However, the origin of the strong anticipation process often appears elusive in many complex systems. Here, we find that the clapping synchronization process may result from the local interaction between two clapping individuals and may result from the more global coordination between two clapping individuals. We introduce two stochastic models for mutually interacting clapping individuals that generate the LRCCs and prove theoretically that the generation of clapping synchronization process needs to consider both local interaction and global matching. This study provides a statistical framework for studying the internal synchronization mechanism of other complex systems. Our theoretical model can also be applied to study the dynamics of other complex systems with the LRCCs, including finance, transportation, and climate. 相似文献
20.
Journal of Radioanalytical and Nuclear Chemistry - A new liquid membrane tidal diffusion model (LMTD) was applied based on three assumptions to analyze the kinetics of Eu(III) adsorption on... 相似文献