全文获取类型
收费全文 | 30742篇 |
免费 | 5369篇 |
国内免费 | 4164篇 |
专业分类
化学 | 22110篇 |
晶体学 | 301篇 |
力学 | 2077篇 |
综合类 | 284篇 |
数学 | 3611篇 |
物理学 | 11892篇 |
出版年
2024年 | 22篇 |
2023年 | 636篇 |
2022年 | 712篇 |
2021年 | 929篇 |
2020年 | 1331篇 |
2019年 | 1285篇 |
2018年 | 1032篇 |
2017年 | 960篇 |
2016年 | 1370篇 |
2015年 | 1440篇 |
2014年 | 1806篇 |
2013年 | 2209篇 |
2012年 | 2857篇 |
2011年 | 2979篇 |
2010年 | 2035篇 |
2009年 | 1958篇 |
2008年 | 2153篇 |
2007年 | 1828篇 |
2006年 | 1802篇 |
2005年 | 1466篇 |
2004年 | 1208篇 |
2003年 | 956篇 |
2002年 | 976篇 |
2001年 | 773篇 |
2000年 | 649篇 |
1999年 | 740篇 |
1998年 | 534篇 |
1997年 | 485篇 |
1996年 | 500篇 |
1995年 | 434篇 |
1994年 | 388篇 |
1993年 | 342篇 |
1992年 | 274篇 |
1991年 | 242篇 |
1990年 | 203篇 |
1989年 | 178篇 |
1988年 | 153篇 |
1987年 | 80篇 |
1986年 | 81篇 |
1985年 | 79篇 |
1984年 | 37篇 |
1983年 | 37篇 |
1982年 | 31篇 |
1981年 | 25篇 |
1980年 | 6篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1972年 | 4篇 |
1957年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Journal of Optimization Theory and Applications - We distinguish two kinds of piecewise linear functions and provide an interesting representation for a piecewise linear function between two normed... 相似文献
2.
Journal of Visualization - Forecast calibration methods based on historical similar atmospheric state are effective means weather forecast accuracy. Conventional approaches search similar forecasts... 相似文献
3.
Nonlinear Dynamics - The classical Kuramoto model serves as a useful tool for studying synchronization transitions in coupled oscillators that is limited to the sinusoidal and pairwise... 相似文献
4.
Nonlinear Dynamics - The nonlinear modes of a non-conservative nonlinear system are sometimes referred to as damped nonlinear normal modes (dNNMs). Because of the non-conservative... 相似文献
5.
Nonlinear Dynamics - The paper studies the stability and control of radial deployment of an electric solar wind sail with the consideration of high-order modes of elastic tethers. The electric... 相似文献
6.
Zheng Xinyan Hu Po Yao Ruxian cheng Jinhe Chang Yiheng Wu Haitao Mei Hongying Sun Shuxiang Chen Qingtai liu Fang Chen Shujing Wen Hua 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2217-2226
Journal of Radioanalytical and Nuclear Chemistry - Enhancement of U(VI) biomineralization by Saccharomyces cerevisiae through addition of inorganic phosphorus was studied in this work. The addition... 相似文献
7.
Alicia Cintora Florian Käfer Chenyun Yuan Christopher K. Ober 《Journal of polymer science. Part A, Polymer chemistry》2022,60(4):666-673
Activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP)-based aqueous miniemulsion polymerization where the polymerization takes place in the stabilized monomer droplets is described. In this work, we compared styrene, n-butyl methacrylate (nBMA) and tert-butyl methacrylate (tBMA) and investigated the influence of their hydrophobicity on dispersity, molecular weight and particle stability based their partition coefficients (logP) (2.67, 2.23, and 1.86, respectively). Tetrabutylammonium bromide (TBAB) was used as a phase transfer agent for the controlled delivery of Cu2+-Br/tris(2-pyridylmethyl)amine (TPMA), a hydrophilic catalyst, into monomer droplets of varying hydrophobicity. The resulting dispersity and particle stability of each polymer is a function of its logP value, with the most hydrophobic monomer (styrene) displaying the narrowest dispersity and most control (Đ < 1.3), and the most hydrophilic polymer poly(tert-butyl methacrylate) (PtBMA) having reduced emulsion stability, determined by the observation of aggregate formation. Selected polymerization parameters, including effects of total ascorbic acid feed concentration and the monomer concentration and their effects on dispersity are reported. The controlled polymerizations of hydrophilic monomers using ARGET-ATRP in miniemulsion conditions and understanding the effect of monomer hydrophilicity on the emulsion stability will broaden the use of ARGET-ATRP in emulsion polymerization for the synthesis of polymer-grafted nanoparticles with hydrophilic corona. 相似文献
8.
9.
Chinese Journal of Polymer Science - The emerging chemical recyclable polymers, such as poly(γ-butyrolactone) (PGBL) and poly((R)-3,4-trans six-membered ring-fused GBL) (P((R)-M)), provide a... 相似文献
10.
Haicun Yang Shuipi Cai Yu Jiang Zheng Cao Wenzhong Ma Fanghong Gong Guoliang Tao Chunlin Liu 《Journal of polymer science. Part A, Polymer chemistry》2022,60(10):1571-1587
The commonly used multi-center initiation methods always lead to the formation of quantities of homopolymer in the surface tailoring based on reverse atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain-transfer (RAFT) polymerization. In this study, a monocenter redox pair constructed of silica bearing tert-butyl hydroperoxide groups and ascorbic acid (SiO2-TBHP/AsAc) was applied to substitute the commonly used initiation method of R-supported RAFT grafting polymerization. All the propagating radicals were restricted on the surface of solid particles during the whole procedure theoretically, resulting in a higher grafting efficiency of 95.1% combined with the “controllable” feature at 10 h. This redox pair was also used to initiate the reverse ATRP in miniemulsion successfully with a grafting efficiency of 86.3% at 10 h. The grafting efficiency obtained under this monocenter initiation method was significantly higher than that of the frequently reported surface modification by reverse ATRP and RAFT polymerization. In addition, the high-efficient surface tailoring was traced and confirmed by nuclear magnetic resonance, Fourier transform infrared, X-ray photoelectron spectroscopy, thermogravimetric analysis, transmission electron microscopy, and other analysis tests. The advantage of this monocenter redox pair will open a new avenue for the potential “high-efficient” surface tailoring of various materials. 相似文献