全文获取类型
收费全文 | 3703篇 |
免费 | 709篇 |
国内免费 | 1398篇 |
专业分类
化学 | 2813篇 |
晶体学 | 134篇 |
力学 | 273篇 |
综合类 | 165篇 |
数学 | 413篇 |
物理学 | 2012篇 |
出版年
2024年 | 6篇 |
2023年 | 33篇 |
2022年 | 131篇 |
2021年 | 142篇 |
2020年 | 106篇 |
2019年 | 122篇 |
2018年 | 109篇 |
2017年 | 167篇 |
2016年 | 114篇 |
2015年 | 166篇 |
2014年 | 208篇 |
2013年 | 261篇 |
2012年 | 250篇 |
2011年 | 279篇 |
2010年 | 306篇 |
2009年 | 342篇 |
2008年 | 383篇 |
2007年 | 317篇 |
2006年 | 340篇 |
2005年 | 307篇 |
2004年 | 250篇 |
2003年 | 180篇 |
2002年 | 196篇 |
2001年 | 180篇 |
2000年 | 170篇 |
1999年 | 129篇 |
1998年 | 90篇 |
1997年 | 57篇 |
1996年 | 42篇 |
1995年 | 59篇 |
1994年 | 31篇 |
1993年 | 41篇 |
1992年 | 44篇 |
1991年 | 27篇 |
1990年 | 38篇 |
1989年 | 25篇 |
1988年 | 37篇 |
1987年 | 26篇 |
1986年 | 19篇 |
1985年 | 12篇 |
1984年 | 16篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 10篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1974年 | 3篇 |
1959年 | 3篇 |
排序方式: 共有5810条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Ming Zhao WANG Guan Liang CAI Ling XIA Jun Jian YAO Hong Yan CHEN Zhao Xing MENG Bo Li LIUDepartment of Chemistry Beijing Normal University Beijing Chemical Defense Institute PLA Beijing 《中国化学快报》2004,15(4):495-497
The crystal structures of two potential tumor imaging agents and therapeutic agents -copper(Ⅱ) complexes with salicylidene-tyrosinato Schiff base and nitrogen-donor chelating Lewis base, [Cu(sal-tyr)(bipy)] 1 and [Cu(sal-tyr)(phen)]2CH3OH 2 are presented. Our work is helpful to get deep understanding of novel 64Cu tumor imaging agents and therapeutic agents. 相似文献
6.
7.
8.
LI Cun YANG Bai-Feng CAI Hao HUANG Nian-Ning 《理论物理通讯》2006,46(2):244-248
One of the basic problems about the inverse scattering transform for solving a completely integrable nonlinear evolutions equation is to demonstrate that the Jost solutions obtained from the inverse scattering equations of Cauchy integral satisfy the Lax equations. Such a basic problem still exists in the procedure of deriving the dark soliton solutions of the NLS equation in normal dispersion with non-vanishing boundary conditions through the inverse scattering transform. In this paper, a pair of Jost solutions with same analytic properties are composed to be a 2 × 2 matrix and then another pair are introduced to be its right inverse confirmed by the Liouville theorem. As they are both 2 × 2 matrices, the right inverse should be the left inverse too, based upon which it is not difficult to show that these Jost solutions satisfy both the first and second Lax equations. As a result of compatibility condition, the dark soliton solutions definitely satisfy the NLS equation in normal dispersion with non-vanishing boundary conditions. 相似文献
9.
Molecular dynamics simulation of thermodynamic properties of NaCl at high pressures and temperatures 总被引:1,自引:0,他引:1
Qifeng Chen Lingcang Cai Dongquan Chen 《Journal of Physics and Chemistry of Solids》2004,65(6):1077-1081
The expansivity, constant-pressure heat capacity, and isothermal bulk modulus of sodium chloride (NaCl) have been obtained by using molecular dynamics method. The calculated thermodynamic parameters are found to be in agreement with the available experimental data. At an extended temperature and pressure ranges, these parameters have also been predicted. The thermodynamic properties of NaCl are summarized in the pressure 0-500 kbar ranges and the temperature up to 1000 K. 相似文献
10.
CAI Guang-Yu LlU Zhong-Min SHI Ren-Min HE Chang-Qing YANG Li-Xin SUN Cheng-LinDalian Institute of Chemical Physics Acadernia Sinica Dalian Iiaorting 《天然气化学杂志》1995,(2)
A new route named as SDTO method for the synthesis of lightolefins from syngas has been proposed.That is to convert syngas todimethylether and then to convert dimethylether to light olefins.The catalystsfor the two conversion reactions have been developed.For the first reaction,the catulySt was synthesized by the combination of methanol synthesis catalystwith γ-Al_2O_3or zeolites which possesses both metallic and acidic functions.Thecatalyst for the second reaction was modified SAPO-34 molecular sieve.Thevariables of the reactions have also been investigated.The results from theserial connection of the two conversion steps without any separation show thatthe yield of C_2~-C_4~- olefins Could be>100g/(m~3 syngas). 相似文献