全文获取类型
收费全文 | 425篇 |
免费 | 14篇 |
国内免费 | 2篇 |
专业分类
化学 | 297篇 |
晶体学 | 1篇 |
力学 | 17篇 |
数学 | 36篇 |
物理学 | 90篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 10篇 |
2017年 | 5篇 |
2016年 | 11篇 |
2015年 | 10篇 |
2014年 | 11篇 |
2013年 | 25篇 |
2012年 | 20篇 |
2011年 | 38篇 |
2010年 | 19篇 |
2009年 | 17篇 |
2008年 | 12篇 |
2007年 | 14篇 |
2006年 | 18篇 |
2005年 | 18篇 |
2004年 | 6篇 |
2003年 | 17篇 |
2002年 | 8篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1998年 | 3篇 |
1994年 | 7篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1984年 | 3篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 6篇 |
1973年 | 13篇 |
1972年 | 5篇 |
1969年 | 4篇 |
1968年 | 5篇 |
1967年 | 5篇 |
1963年 | 2篇 |
1959年 | 2篇 |
1957年 | 2篇 |
1939年 | 3篇 |
1937年 | 2篇 |
排序方式: 共有441条查询结果,搜索用时 15 毫秒
1.
Rathore Vikas Tiwari Budhi Sagar Nema Sudhir Kumar 《Plasma Chemistry and Plasma Processing》2022,42(1):109-129
Plasma Chemistry and Plasma Processing - The present study has been carried to investigate the interaction and effect of plasma activated water (PAW) on pea seeds. PAW is produced with the... 相似文献
2.
Tapasi Chand Laxmikanta Khamari Deepak Chopra Saptarshi Mukherjee Manmohan Kapur 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(43):e202200723
A one-step Rh-catalyzed site-selective ortho-C−H alkynylation of perylene as well as naphthalene mono- and diimides is reported. A single step regioselective access to ortho-C−H alkynylated derivatives of these ryleneimides not only increases the step economy of the ortho-functionalization on these dyes but also provides a quick access route towards highly functionalized dyes that have potential optoelectronic applications. Increased solubility of tetra(triisopropylsilyl)acetylenyl PDIs in organic solvents greatly enhances their utility for further derivatization. 相似文献
3.
Anirudh Pradhan Sudhir Kumar Srivastav Kanti R. Jotania 《Czechoslovak Journal of Physics》2004,54(2):255-272
Some cylindrically symmetric inhomogeneous viscous-fluid cosmological models with electromagnetic field are obtained. To get
a solution a supplementary condition between metric potentials is used. The viscosity coefficient of bulk viscous fluid is
assumed to be a power function of mass density. Without assuming anyad hoc law, we obtain a cosmological constant as a decreasing function of time. The behaviour of the electromagnetic field tensor
together with some physical aspects of the model are also discussed. 相似文献
4.
Sudhir Thattey 《Annalen der Physik》1991,503(5):353-361
A theory, that is an initial step towards bridging the gap between Lorentz and Dirac theories of electrons, is presented. An electromagnetic Lagrangian density is postulated, such that, the theory can be cast into a form, similar to Dirac theory. Electromagnetic interpretation of conserved currents, and of usual bilinear covariants in the Dirac theory, is obtained. A counterpart of Abraham-Lorentz equation, with oscillatory solutions is derived. Self-energy of electrons is expressed in terms of their self-potentials and self-currents. 相似文献
5.
6.
7.
8.
Polymethyl methacrylate (PMMA), polyethyl methacrylate (PEMA) and polybutyl methacrylate (PBuMA) containing ferric chloride and ferrous sulphate as stabilisers, were prepared by free radical polymerization. Mössbauer spactra of ferrous sulphate stabilised polymers don't show any change in the value of isomer shift (1.30 mm/s) while quadrupole splitting values are quite different from those for pure ferrous sulphate. This indicates that environment of Fe2+ moiety changes in polymers and thus stabilises the polymers. In case of ferric chloride stabilised polymers the isomer shift values don't differ significantly for different polymethacrylates but quadrupole splitting values increase from polymethyl methacrylate to polybutyl methacrylate. The TGA analysis shows that the inclusion of iron salts stabilises the polymers by 40°C (approx.) and at higher temperatures α-Fe2O3 is formed. 相似文献
9.
10.
A. B. Deshpande S. M. Kale S. L. Kapur 《Journal of polymer science. Part A, Polymer chemistry》1973,11(6):1307-1315
Polymerization of methyl methacrylate has been studied with the chromium acetylacetonate–triisobutyl aluminum catalyst system in benzene medium at 40°C. These studies have been carried out at an Al/Cr ratio of 12 to compare the behavior with the previously studied chromium acetyl acetonate–triethyl aluminum catalyst system. The enhanced yield and gelling of polymer suggests a free-radical mechanism of polymerization. Further, the kinetics of polymerization and the heterotactic structure of polymer as determined by NMR examination have led to confirmation of the freeradical mechanism of polymerization of methyl methacrylate by an excess of triisobutylaluminum in the presence of catalyst complex. 相似文献