全文获取类型
收费全文 | 2012篇 |
免费 | 252篇 |
国内免费 | 212篇 |
专业分类
化学 | 1215篇 |
晶体学 | 33篇 |
力学 | 92篇 |
综合类 | 43篇 |
数学 | 201篇 |
物理学 | 892篇 |
出版年
2024年 | 8篇 |
2023年 | 37篇 |
2022年 | 68篇 |
2021年 | 58篇 |
2020年 | 58篇 |
2019年 | 83篇 |
2018年 | 75篇 |
2017年 | 49篇 |
2016年 | 77篇 |
2015年 | 66篇 |
2014年 | 79篇 |
2013年 | 109篇 |
2012年 | 153篇 |
2011年 | 146篇 |
2010年 | 101篇 |
2009年 | 116篇 |
2008年 | 108篇 |
2007年 | 94篇 |
2006年 | 94篇 |
2005年 | 109篇 |
2004年 | 93篇 |
2003年 | 73篇 |
2002年 | 64篇 |
2001年 | 93篇 |
2000年 | 48篇 |
1999年 | 53篇 |
1998年 | 51篇 |
1997年 | 40篇 |
1996年 | 34篇 |
1995年 | 37篇 |
1994年 | 26篇 |
1993年 | 23篇 |
1992年 | 16篇 |
1991年 | 16篇 |
1990年 | 33篇 |
1989年 | 17篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 19篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 1篇 |
排序方式: 共有2476条查询结果,搜索用时 15 毫秒
991.
百焦耳级XeCl准分子激光实验研究 总被引:4,自引:3,他引:1
介绍了西北核技术研究所利用“闪光Ⅱ号”强流相对论电子束加速器作泵浦源研制的百焦耳级XeCl准分子激光器的主要性能和实验结果。 相似文献
992.
基于StuberG.L.的系统模型,研究带反馈链路的选择式频率分集与编码FH/MFSK系统在具有加性白高斯噪声(AWGN)的瑞利衰落信道中的编码性能,给出了采用RS码、双-k码、重发码时,编码前与编码后系统的码符差错概率与比特能量噪声比的关系曲线.研究结果表明:无编码时,单纯增加分集重数L对系统性能的改善并不是十分明显的,只有同时采用分集与编码技术,才能有效地改善系统的性能. 相似文献
993.
Xing Zhu Gui-Song Huang He-Tian Zhou Xiao Yang Zhe Wang Yong Ling Yuan-Dong Dai Zi-Zhao Gan 《Optical Review》1997,4(1):236-239
We have developed a novel sample-tip regulation for a near-field optical microscope: an ultrasonic resonance regulation method. The regulation range is from 0 to 50 nm. It shows not only stability, simplicity in construction, but also versatility in vacuum, magnetic field, and low temperature environments. The main advantage of this technique is that it is a non-optical detecting scheme, which is very important for near-field spectroscopy. Such construction can also be used as a force microscope to study the topography of insulating samples. The laser light induced force interaction in the near-field range has been observed for the first time, showing that aided by laser radiation, the shear force between sample and tip can be changed depending on the type of sample. This can be interpreted as the light induced optical tip-sample interaction of light pressure effect. The van der Waals dispersion energy and the optical binding energy induced by laser beam between dielectric tip and samples play important role. The effect confirms a theoretical prediction. This new technique and phenomenon will add new aspects to near-field optics. 相似文献
994.
995.
使用全面搜索和优化处理相结合的方法,由一组余震的P波初动解资料可以推断出余震区的构造应力的主轴方向,应力主值的相对大小(1),并同时确定了余震的两个P波节面中的断层面。对1976年唐山地震相1966年邢台地震的余震资料的计算处理,都给出了余震区的主压应力为水平东西向,主张应力为近水平南北向的结果。因此可以认为,本方法对于用地震资料研究应力场是一个有用的工具。 相似文献
996.
Brandenburg G Cinabro D Liu T Saulnier M Wilson R Yamamoto H Bergfeld T Eisenstein BI Ernst J Gladding GE Gollin GD Palmer M Selen M Thaler JJ Edwards KW McLean KW Ogg M Bellerive A Britton DI Hyatt ER Janicek R MacFarlane DB Patel PM Spaan B Sadoff AJ Ammar R Baringer P Bean A Besson D Coppage D Copty N Davis R Hancock N Kotov S Kravchenko I Kwak N Kubota Y Lattery M Momayezi M Nelson JK Patton S Poling R Savinov V Schrenk S Wang R Alam MS Kim IJ Ling Z Mahmood AH O'Neill JJ Severini H Sun CR 《Physical review letters》1995,75(21):3804-3808
997.
Bergfeld T Eisenstein BI Ernst J Gladding GE Gollin GD Johnson E Karliner I Palmer M Selen M Thaler JJ Edwards KW Bellerive A Britton DI Janicek R MacFarlane DB McLean KW Patel PM Sadoff AJ Ammar R Baringer P Bean A Besson D Coppage D Darling C Davis R Hancock N Kotov S Kravchenko I Kwak N Anderson S Kubota Y Lattery M O'Neill JJ Patton S Poling R Riehle T Smith A Savinov V Alam MS Athar SB Ling Z Mahmood AH Severini H Timm S Wappler F Anastassov A Blinov S Duboscq JE Fulton R Fujino D Gan KK 《Physical review letters》1996,77(22):4503-4507
998.
Study on the Phase Behavior of Supercritical CO2/Dynol—604/Water System and Solubilization of Methyl Orange in the Microemulsions 总被引:1,自引:0,他引:1
It was found that Dynol-604, a non-fluorous and no silicon-containing nonionic surfactant,was soluble in supercritical (SC) CO2. The phase behavior of SC CO2/Dynol-604/water system was studies. The results showed that one-phase water-in-CO2 microemulsions could be fromed. The solubilization of methyl orange in the microemulsions proved further the existence of water domain in the microemulsions. 相似文献
999.
JinLingCHAI ShouQingWANG GanZuoLI QingXU YanHongGAO 《中国化学快报》2004,15(6):699-702
A novel kinetic mechanism of esterification reaction of 1-hexanoic acid with 1-butanol,catalyzed by lipase, was studied in water-in-oil microemulsions. The microemulsions were formed by alkyl polyglucoside C10G1.54/1-butanol/cyclohexane/phosphate buffer solution. The restult shows that when the ratio of mol concentration of 1-butanol to 1-hexanoic acid is about 3.0,the initial rate V0 get the maximum values. This phenomenon was explained by the modified fishlike phase diagrams. 相似文献
1000.
Natural products that act as highly specific, small-molecule protein-binding agents and as modulators of protein-protein interactions are highly complex and exhibit functional groups with three-dimensional and stereochemical diversity. The complex three-dimensional display of chiral functional groups appears to be crucial for exhibiting specificity in protein binding and in differentiating between closely related proteins. The development of methods that allow a high-throughput access to three-dimensional, skelatally complex, polycyclic compounds having few asymmetric diversity sites is essential and a highly challenging task. In the postgenomic chemical biology age, in which there is a great desire to understand protein-protein interactions and to dissect protein networking-based signaling pathways by small molecules, the need for developing "stereocontrolled, diversity-oriented synthesis" methods to generate natural product-like libraries is of utmost importance. 相似文献