全文获取类型
收费全文 | 261篇 |
免费 | 22篇 |
国内免费 | 35篇 |
专业分类
化学 | 190篇 |
晶体学 | 2篇 |
力学 | 14篇 |
综合类 | 8篇 |
数学 | 45篇 |
物理学 | 59篇 |
出版年
2024年 | 1篇 |
2023年 | 17篇 |
2022年 | 18篇 |
2021年 | 22篇 |
2020年 | 32篇 |
2019年 | 30篇 |
2018年 | 16篇 |
2017年 | 8篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 8篇 |
2013年 | 17篇 |
2012年 | 13篇 |
2011年 | 23篇 |
2010年 | 8篇 |
2009年 | 2篇 |
2008年 | 13篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 7篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 1篇 |
排序方式: 共有318条查询结果,搜索用时 15 毫秒
1.
2.
Pan Yifei Department of Mathematical Sciences Indiana University-Purdue University Fort Wayne Fort Wayne IN - U.S.A. School of Mathematics Informatics Jiangxi Normal University Nanchang China 《中国科学A辑(英文版)》2005,48(Z1)
It is proved that every proper holomorphic self-map of a smooth bounded Reinhardt domain of D'Angelo finite type in Cn (n > 1) is an automorphism. 相似文献
3.
The selectivity of intermolecular force is caused by the special interaction between two adaptable groups on the molecules. π bond and conjugated π bonds such as benzene ring are negative charged groups,which may attract stongly positively charged H groups such as 3H in β-C_6H_6Cl_6, and repulse other ne- gatively charged groups such as-C=O(Q). Our experiments show that the reduced retention time tr of benzene on non- polar β-C_6H_6Cl_6 is much greater than that on polar fixed phases such as CH_3— —NO_2 in gas chromatography and that the het of solvation of β-C_6H_6Cl_6 in benzene is also much greater than that of the polar α-C_6H_6Cl_6 and γ-C_6H_6Cl_6. This can′t be explained by the usual Van de Waals′ force. It results from the selective intermoleccular force.... 相似文献
4.
Polychlorinated biphenyls (PCBs) and chlorobenzenes (CBzs) are two classes of dioxin precursors formed in municipal solid waste incinerators (MSWIs); they produce negative health effects similar to those of dioxins. Reducing the analytical time required for determining the concentrations of these compounds in MSWIs is important for quickly evaluating their importance and assessing associated health risks. In the present study, water is used as a safe and environmentally friendly solvent in microwave-assisted extraction (MAE) for PCB and CBz analyses. MAE is compared with traditional Soxhlet extraction (SE) to determine the extraction efficiencies. The evaluation of extraction efficiencies shows that MAE has a high extraction efficiency compared with that of SE when water content is lower than 60%. Furthermore, the extraction time and organic solvent consumption are reduced with MAE compared with SE. 相似文献
5.
采用草酸沉淀法,通过填加表面活性剂四丁基溴化铵、十六烷基三甲基溴化铵和金属离子K+,Mg2+,Ba2+,制备出稀土发光材料Y2O3Eu3+,利用XRD与激发和发射光谱等测试手段对样品的结构与光学性能进行了表征,考察了同时加入不同表面活性剂和金属离子对Y2O3Eu3+的结构和发光性质的影响.结果表明加入表面活性剂和金属离子对发光材料Y2O3Eu3+的发光性能有较大的影响,其中以同时加入四丁基溴化铵和Ba2+以及加入十六烷基三甲基溴化铵和Mg2+对Y2O3Eu3+粉体的发光性能影响最大. 相似文献
6.
Abstract— The primary and secondary electron transfer reactions which occurred upon laser flash photolysis of electrically neutral and positively-charged lipid bilayer vesicles containing chlorophyll, benzoquinone and cytochrome c were determined by time-resolved difference spectral and kinetic measurements, and compared with previous results obtained with negatively-charged vesicles (Y. Fang and G. Tollin, Photochem. Photobiol. 1988). The extent to which oxidized cytochrome c could function as an electron acceptor from triplet state chlorophyll, and reduced cytochrome c could act as an electron donor to chlorophyll cation radical, decreased from negatively-charged to electrically neutral to positively-charged vesicles, in agreement with expectations based on changes in the ability of cytochrome c to bind to the bilayer. In all three types of vesicles, cytochrome c reduction by benzoquinone anion radical occurred in the aqueous phase. 相似文献
7.
Biranje Santosh Shivaji Sun Jianzhong Shi Yifei Yu Sujie Jiao Haixin Zhang Meng Wang Qianqian Wang Jin Liu Jun 《Cellulose (London, England)》2021,28(14):8899-8937
Cellulose - Excessive hemorrhage is a leading cause of death to trauma patients, especially in combat and civilian accidents. The main priority in the medical treatment of trauma patients is to... 相似文献
8.
It is shown in this paper that the Schrodinger operator with a potential satisfying ∣V(x)∣ ≤ M/∣x∣2a.e. in the unit ball B has the strong unique continuation property in H2,2(B) for for n≥2. 相似文献
9.
Song Zhongxian Fu Yongmei Ning Ping Liu Hongpan Ren Dong Kang Haiyan Liu Biao Mao Yanli Guo Yifei Zhang Qiulin 《Research on Chemical Intermediates》2019,45(4):2313-2326
Research on Chemical Intermediates - The effect of different pH values (8, 9, 10 and 11) on the catalytic activity over CeSiW catalysts was investigated for the selective catalytic reduction of NO... 相似文献
10.