全文获取类型
收费全文 | 1002篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 406篇 |
晶体学 | 15篇 |
力学 | 83篇 |
数学 | 168篇 |
物理学 | 334篇 |
出版年
2022年 | 7篇 |
2021年 | 13篇 |
2020年 | 17篇 |
2019年 | 18篇 |
2018年 | 31篇 |
2017年 | 28篇 |
2016年 | 35篇 |
2015年 | 12篇 |
2014年 | 21篇 |
2013年 | 43篇 |
2012年 | 44篇 |
2011年 | 42篇 |
2010年 | 33篇 |
2009年 | 40篇 |
2008年 | 29篇 |
2007年 | 52篇 |
2006年 | 34篇 |
2005年 | 27篇 |
2004年 | 19篇 |
2003年 | 29篇 |
2002年 | 17篇 |
2001年 | 17篇 |
2000年 | 14篇 |
1999年 | 9篇 |
1998年 | 18篇 |
1997年 | 18篇 |
1996年 | 17篇 |
1995年 | 15篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1990年 | 7篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1986年 | 14篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 9篇 |
1981年 | 13篇 |
1979年 | 9篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1976年 | 11篇 |
1975年 | 11篇 |
1974年 | 13篇 |
1973年 | 11篇 |
1972年 | 8篇 |
1971年 | 13篇 |
1970年 | 9篇 |
1969年 | 9篇 |
排序方式: 共有1006条查询结果,搜索用时 0 毫秒
41.
Andreas Zerr Nikolay Chigarev Ovidiu Brinza Sergey M. Nikitin Alexey M. Lomonosov Vitalyi Gusev 《固体物理学:研究快报》2012,6(12):484-486
The elastic moduli of the dense polycrystalline oxygen‐bearing η‐Ta2N3, a novel hard and tough high‐pressure (HP) material, were measured using the laser ultrasonic technique. The bulk modulus was determined to be B0 = 281(15) GPa which is only ~11% below that from HP compression measurements. Our value of the shear modulus G0 = 123(2) GPa is below those ones predicted theoretically for model structures. The discrepancies in G0 could be due to a substitution of an‐ ions and the formation of cation vacancies in η‐Ta2N3. Self‐healing behaviour of η‐Ta2N3 by mechanical polishing was observed and confirmed by two independent experimental methods. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
42.
A.V. Nikitin M. Rey J.P. Champion Vl.G. Tyuterev 《Journal of Quantitative Spectroscopy & Radiative Transfer》2012,113(11):1034-1042
The MIRS software for the modeling of ro-vibrational spectra of polyatomic molecules was considerably extended and improved. The original version [Nikitin AV, Champion JP, Tyuterev VlG. The MIRS computer package for modeling the rovibrational spectra of polyatomic molecules. J Quant Spectrosc Radiat Transf 2003;82:239–49.] was especially designed for separate or simultaneous treatments of complex band systems of polyatomic molecules. It was set up in the frame of effective polyad models by using algorithms based on advanced group theory algebra to take full account of symmetry properties. It has been successfully used for predictions and data fitting (positions and intensities) of numerous spectra of symmetric and spherical top molecules within the vibration extrapolation scheme. The new version offers more advanced possibilities for spectra calculations and modeling by getting rid of several previous limitations particularly for the size of polyads and the number of tensors involved. It allows dealing with overlapping polyads and includes more efficient and faster algorithms for the calculation of coefficients related to molecular symmetry properties (6C, 9C and 12C symbols for C3v, Td, and Oh point groups) and for better convergence of least-square-fit iterations as well. The new version is not limited to polyad effective models. It also allows direct predictions using full ab initio ro-vibrational normal mode Hamiltonians converted into the irreducible tensor form. Illustrative examples on CH3D, CH4, CH3Cl, CH3F and PH3 are reported reflecting the present status of data available. It is written in C++ for standard PC computer operating under Windows. The full package including on-line documentation and recent data are freely available at http://www.iao.ru/mirs/mirs.htm or http://xeon.univ-reims.fr/Mirs/ or http://icb.u-bourgogne.fr/OMR/SMA/SHTDS/MIRS.html and as supplementary data from the online version of the article. 相似文献
43.
New invariant tests of normality based on Shepp property are constructed and studied. Test statistics are functions of a U-empirical process. The limiting distributions and large deviations of test statistics under the null-hypothesis are described. Local Bahadur efficiency of new tests is calculated under simplest parametric alternatives (shift, skew, and contamination alternatives). 相似文献
44.
Kirill Nikitin Helge Müller-Bunz Gérard Jaouen Michael J. McGlinchey 《Journal of organometallic chemistry》2010,695(4):595-608
The McMurry coupling of (tetraphenylcyclobutadiene)cobalt(cyclopentadienyl) ketones, (C4Ph4)Co[C5H4C(O)R], where R = Me, 3a, or Et, 3b, with a range of substituted benzophenones furnished a series of cobaltifens, organometallic analogues of tamoxifen whereby a phenyl ring has been replaced by an organo-cobalt sandwich moiety. These systems of the general formula (η4-C4Ph4)Co[η5-C5H4C(R)C(Ar)Ar′], where R = Me or Et, and Ar = Ar′ = p-C6H4X where X is OH, 2a and 2b, OMe, 2c and 2d, OBn, 2e and 2f, or O(CH2)2NMe2, 12a and 12b, and where Ar = C6H4OH and Ar′ = C6H4O(CH2)2NMe2, 2g and 2h, have been characterised by NMR spectroscopy and/or X-ray crystallography. The effect of 2a and 2b, 2g and 2h, and 12a and 12b on the growth of MCF-7 (hormone-dependent) and MDA-MB-231 (hormone-independent breast cancer cells) was studied. The dihydroxycobaltifens 2a and 2b exhibit a strong estrogenic effect on MCF-7 cells while the aminoalkyl-hydroxycobaltifens, 2g and 2h, were found to be only slightly cytotoxic on MDA-MB-231 cells (IC50 = 27.5 and 17 μM); surprisingly, however, the bis-(dimethylaminoethoxy)cobaltifens, 12a and 12b were shown to be highly cytotoxic towards both cell lines (IC50 = 3.8 and 2.5 μM). 相似文献
45.
V. F. Mironov Yu. I. Sal’nikov G. A. Boos D. A. Tatarinov A. P. Nikitin 《Russian Journal of General Chemistry》2013,83(6):1087-1093
Four new compounds, asymmetrical phosphine oxides containing 2-hydroxyphenylethenyl fragment in cis-orientation with respect to the phosphine oxide: dibutyl-, diphenyl-, dibenzyl-, and dinaphthyl-2-(2-hydroxy-5-chlorophenyl)-2-phenyl-ethenylphospnine oxides, have been studied in aqueous ethanol (80 vol % of EtOH) by means of potentiometry and spectrophotometry at 25±0.1°C, and their acid-base and complexing properties estimated. 相似文献
46.
The effect of pressure in solutions of chitosan in carbonic acid with the AgNO3 precursor on the structure of cast nanocomposite films with silver nanoparticles has been studied for the first time. The size of silver nanoparticles can be controlled by varying pressure in carbonic acid. 相似文献
47.
E. Ardashev V. Avdeichikov V. Balandin G. Bogdanova V. Dunin O. Gavrishchuk V. Golovkin S. Golovnya S. Gorokhov A. Isupov A. Kazakov A. Kholodenko A. Kiryakov E. Kokoulina A. Kutov N. Kuzmin I. Lobanov V. Nikitin Yu. Petukhov G. Pokatashkin M. Polkovnikov V. Popov S. Reznikov V. Rogov V. Ronzhin I. A. Rufanov V. Ryadovikov Yu. Tsyupa V. Volkov A. Vorobiev N. Zhidkov L. Zolin 《The European Physical Journal A - Hadrons and Nuclei》2016,52(8):261
48.
Adsorption of benzene, anisole, and nitrobenzene on hydroxylated silica gel from binary and ternary solutions (adsorbate--n-hexane and adsorbate--n-hexane--terahydrofuran) was studied by HPLC. The equation that describes the adsorbate retention as a function of its concentration in binary and ternary solutions was proposed. The equation makes it possible to calculate the adsorption isotherms and adsorption equilibrium constants directly from chromatograms using the retention parameters and equilibrium concentrations of the adsorbate in the mobile phase. 相似文献
49.
O. M. Nikitin T. V. Magdesieva O. V. Polyakova P. K. Sazonov K. V. Gor’kov E. V. Zolotukhina M. A. Vorotyntsev 《Russian Journal of Electrochemistry》2018,54(7):608-611
A composite material in the form of powder is synthesized by a redox reaction in mixed aqueous solution of Pd(NH3)4Cl2 + pyrrole. The composite consists of polypyrrole globules with palladium nanoparticles uniformly distributed inside the latter. Being applied as a film on the electrode surface, both components of this material exhibit redox activity. Palladium particles inside the composite exhibit catalytic properties in cyanation of styryl bromides, a reaction widely used in fine organic synthesis. 相似文献
50.
S. V. Nikitin G. V. Pokhvisneva T. V. Ternikova P. B. Gordeev I. M. Chistokhvalov G. A. Smirnov O. A. Luk’yanov 《Russian Chemical Bulletin》2018,67(8):1445-1451
Synthetic procedures towards new N-β-hydroxyethyl- and N-β-bromoethylated 1,1’-[methyl enebis(oxy)]bis(triaz-1-ene 2-oxides) were developed. N-β-Nitroxyethyl[methylenebis(oxy)]- bis(triaz-1-ene 2-oxides) were first synthesized by nitration of N-β-hydroxyethyl derivatives and nucleophilic substitution of the bromine atom of N-β-bromoethyl derivatives. The first representative of a new class of energetic compounds, namely, (1-nitroxymethoxy)triaz-1-ene 2-oxide, was synthesized. 相似文献