全文获取类型
收费全文 | 175篇 |
免费 | 4篇 |
国内免费 | 5篇 |
专业分类
化学 | 114篇 |
晶体学 | 3篇 |
数学 | 10篇 |
物理学 | 57篇 |
出版年
2023年 | 2篇 |
2022年 | 14篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 18篇 |
2012年 | 10篇 |
2011年 | 7篇 |
2010年 | 9篇 |
2009年 | 14篇 |
2008年 | 10篇 |
2007年 | 9篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有184条查询结果,搜索用时 15 毫秒
41.
Summary The prompt-muon flux generated directly from the decay of short-lived particles like D-mesons and Λc-hyperons produced during primary cosmic proton-air collisions has been estimated. The inclusive production cross-sections
of charmed particles based on the recombination of quark parton model developed by Bugaevet al. and the primary-nucleon spectrum based on the latest JACEE balloon flight data have been used in this investigation. The
derived direct muon spectrum has been compared with the earlier results of Elbertet al., Inazawaet al. Bugaevet al. and Allkofer and Bhattacharyya. 相似文献
42.
Kapoor Ramesh Kataria Ashok Kapoor Pratibha Venugopalan P. 《Transition Metal Chemistry》2004,29(4):425-429
Transition Metal Chemistry - The crystal and molecular structure of a 2:1 complex of CoCl2 with DETP (N,N,N′,N′-tetraethylpyridine-2,6-dithiocarboxamide), has been determined. The... 相似文献
43.
Stephen B Cronin Yu-Ming Lin Oded Rabin Marcie R Black Gene Dresselhaus Mildred S Dresselhaus Pratibha L Gai 《Microscopy and microanalysis》2002,8(1):58-63
Nanowires of bismuth with diameters ranging from 10 to 200 nm and lengths of 50 microm have been synthesized by a pressure injection method. Nanostructural and chemical compositional studies using environmental and high resolution transmission electron microscopy with electron stimulated energy dispersive X-ray spectroscopy have revealed essentially single crystal nanowires. The high resolution studies have shown that the nanowires contain amorphous Bi-oxide layers of a few nanometers on the surface. In situ environmental high resolution transmission electron microscopy (environmental-HRTEM) studies at the atomic level, in controlled hydrogen and other reducing gas environments at high temperatures demonstrate that gas reduction can be successfully applied to remove th oxide nanolayers and to maintain the dimensional and structural uniformity of the nanowires, which is key to attaining low electrical contact resistance. 相似文献
44.
Pratibha L Gai 《Microscopy and microanalysis》2002,8(1):21-28
We present the development of in situ wet environmental transmission electron microscopy (wet-ETEM) for direct probing of controlled liquid-catalyst reactions at operating temperatures on the nanoscale. The first nanoscale imaging and electron diffraction of dynamic liquid hydrogenation and polymerization reactions in the manufacture of polyamides reported here opens up new opportunities for high resolution studies of a wide range of solution-solid and solution-gas-solid reactions in the chemical and biological sciences. 相似文献
45.
R. Purushottamudu Pratibha Nuthakki 《Zeitschrift fur Physik C Particles and Fields》1982,14(3):257-261
Current algebra and partially conserved axial-vector current (PCAC) hypothesis are applied to study the proton-antiproton annihilation process \(\bar pp \to K^ + K^ - 4\pi ^0 \) , treating all the emitted pions as soft. While the σ-terms are ignored, the double commutators giving rise to the divergence of axial-vector currents and representing π?π effects are retained. We express the rate for the process in a fully differential form in terms of the chosen variables and normalize it to the differential rate for the corresponding process without the soft pions. Branching ratios obtained after numerical integration of the expressions are given for various centre-of-mass energies and compared with the available experimental data. 相似文献
46.
47.
Three compounds ( 1 – 3 ) were synthesized, where ethynylferrocene is substituted at different positions of anthracene and anthraquinone, and their biological properties were investigated. Compounds 1 – 3 were characterized using NMR and mass spectroscopies and confirmed by their single‐crystal X‐ray structure. They were also characterized from electronic and photophysical properties. All three crystal structures were optimized using density functional theory calculations. The presence of C–H???π interactions in 1 – 3 leads to the formation of two‐ and three‐dimensional networks. The bioactivity of 1 – 3 was expressed by molecular docking with various cancerous proteins, which participated in progression of cancer. Compound 2 displayed the best interaction with cancer‐related Aurora A protein in terms of both binding energy (?10.61 kcal mol?1) as well as inhibition constant (16.74 nM). The molecular docking result also coincides with cytotoxicity on cancer cell lines (A375, HeLa) and DNA/protein binding affinity. 相似文献
48.
Pratibha Sharma Ashok Kumar Priti Pandey 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):583-594
1,2-Dialkyl-3-arylazo quinolinium chloride 1 having N-methylene group activated by the insertion of arylazo site react with phosphorus trichloride to give N-(dichloro phosphinomethylene) quinolinium ylide 2 . The site of the reaction is determined by the relative activation of 1- and 2-methylene groups, in the absence of sufficient activation of N-methylene group, reactions occur at the 2-methylene group to give dichloro phosphinylated anhydrobases 5 and 11. 相似文献
49.
50.
New series of triorganotin(IV) complexes with 4′‐nitrobenzanilide semicarbazone (L1H) and 4′‐nitrobenzanilide thiosemicarbazone (L2H) of the type [R3Sn(L)] (R = ‐CH3, ‐C6H5 and n‐C4H9) were synthesized under microwave irradiation. All the complexes were characterized by elemental analysis, conductance measurements, molecular weight determinations and spectral data, viz., IR, UV–vis, 1H, 13C and 119Sn NMR. The central tin atoms of these complexes are all five‐coordinated with trigonal bipyramidal geometry. In order to assess their growth inhibitory potency semicarbazone, thiosemicarbazone and their triorganotin(IV) complexes were tested in vitro against some pathogenic fungi and bacteria. Also the ligands and their organotin(IV) complexes were studied to assess the effects of long‐term ingestion of these compounds on fertility, body and reproductive organ weights. The biochemical analyses were also performed on blood samples and reproductive organs of male rats. The findings have been presented in this paper. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献