全文获取类型
收费全文 | 30808篇 |
免费 | 8861篇 |
国内免费 | 11332篇 |
专业分类
化学 | 16569篇 |
晶体学 | 1133篇 |
力学 | 4007篇 |
综合类 | 556篇 |
数学 | 1689篇 |
物理学 | 27047篇 |
出版年
2024年 | 272篇 |
2023年 | 1058篇 |
2022年 | 1171篇 |
2021年 | 1349篇 |
2020年 | 900篇 |
2019年 | 1300篇 |
2018年 | 781篇 |
2017年 | 1201篇 |
2016年 | 1211篇 |
2015年 | 1482篇 |
2014年 | 2915篇 |
2013年 | 2128篇 |
2012年 | 2090篇 |
2011年 | 2343篇 |
2010年 | 2103篇 |
2009年 | 2262篇 |
2008年 | 2547篇 |
2007年 | 2158篇 |
2006年 | 2123篇 |
2005年 | 1984篇 |
2004年 | 2092篇 |
2003年 | 2084篇 |
2002年 | 1762篇 |
2001年 | 1626篇 |
2000年 | 1243篇 |
1999年 | 1059篇 |
1998年 | 996篇 |
1997年 | 1018篇 |
1996年 | 876篇 |
1995年 | 825篇 |
1994年 | 757篇 |
1993年 | 619篇 |
1992年 | 618篇 |
1991年 | 598篇 |
1990年 | 522篇 |
1989年 | 492篇 |
1988年 | 165篇 |
1987年 | 115篇 |
1986年 | 62篇 |
1985年 | 36篇 |
1984年 | 14篇 |
1983年 | 23篇 |
1982年 | 16篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
温度对PSⅡCP4 7/D1/D2/Cytb559复合物荧光光谱特性的影响 总被引:3,自引:3,他引:0
采用激励光源为514.5 nm的分幅扫描单光子计数荧光光谱装置对经20℃、42℃和48℃不同温度处理后的反应中心复合物CP47/D1/D2/Cyt b559的荧光光谱特性进行了研究.经解析,获得不同温度处理后,CP47/D1/D2/Cyt b559复合物最大峰值未发生变化,均在682 nm,说明Chla670的能量都由Chla682接收,但损耗愈来愈小,在48℃时,损耗程度最小,而其荧光百分比未发生多大变化.振动副带~700 nm和~740 nm的中心波长都发生蓝移,在不同温度下分别为:20℃ 703 nm,749 nm;42℃ 697 nm,744 nm;48℃ 694 nm,740 nm.因此可以推测温度的升高,影响了CP47/D1/D2/Cyt b559色素蛋白的二级结构以及色素分子的空间位置,使最大峰值处的荧光强度逐渐降低,振动副带逐渐蓝移.42℃的温度已造成影响,48℃影响较大. 相似文献
143.
144.
145.
XiWenHE HongShengGUO YuMeiJIA 《中国化学快报》2003,14(9):979-982
In order to obtain mechanically stable membrane for practical application, the imprinted polymer was synthesized in the pores of polyfluoromembrane, the binding and transport ability of the membrane were studied. 相似文献
146.
A theory is developed for incoherently coupled grey photovoltaic soliton families in unbiased photovoltaic crystals. Both the properties and the forming conditions of these soliton families are discussed in detail. The theory can also be used to investigate the dark photovoltaic soliton families. Some relevant examples are presented, in which the photovoltaic-photorefractive crystal is of lithium niobate type. 相似文献
147.
Dissociative Chemisorption of an H2(v,j) Molecule on Rigid Ni (100) Surface: Dependence on Surface Topologies and Initial Rovibrational States of the Molecules 下载免费PDF全文
MeryemEvecen MustafaBǒyǚkata MehmetCivi ZiyaB.Gǚvenc 《中国物理快报》2005,22(2):420-423
The H2(v,j) Ni(100) collision system has been studied to understand the effects of the surface sites and initial rovibrational states of the molecule on molecule-surface interactions, by a quasiclassical molecular dynamic simulation method. Dissociative adsorption of an H2 molecule on the rigid Ni(100) surface is investigated at topologically different three sites of the surface. Interaction between the molecule and Ni surface was described by a London-Eyring-Polani-Sato (LEPS) potential. Dissociative chemisorption probabilities of the H2(v, j) molecule on various sites of the surface are presented as a function of the translation energies between 0.001-1.0eV. The probabilities obtained at each collision site have unique behaviour. At lower collision energies, indirect processes enhance the reactivity, effects of the rotational excitations and impact sites on the reactivity are more pronounced. The results are compared with the available studies. The physical mechanisms underlying the results and quantum effects are discussed. 相似文献
148.
We analyse the influence of properties of organic/organic interface (OOI) on the characteristics of recombination efficiency of organic double-layer light-emitting diodes. Based on the disordered hopping theory model, spatial and energetic disorder of hopping states are also discussed for the case of space charge limited currents in hole transmitting layers but injection-limited currents in electron transporting layers. The results show that the recombination efficiency increases firstly and then decreases for different OOI parameters, and there is a maximum value changed with different spatial disorder parameters and energetic disorder scale. Different spatial disorder parameters make carrier mobilities change greatly, and the energetic disorder scale causes various localized state densities. Our calculated results are qualitatively in agreement with the experimental data. 相似文献
149.
150.