全文获取类型
收费全文 | 550篇 |
免费 | 7篇 |
专业分类
化学 | 343篇 |
晶体学 | 10篇 |
力学 | 23篇 |
数学 | 63篇 |
物理学 | 118篇 |
出版年
2022年 | 10篇 |
2021年 | 15篇 |
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 12篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 57篇 |
2012年 | 27篇 |
2011年 | 22篇 |
2010年 | 23篇 |
2009年 | 15篇 |
2008年 | 23篇 |
2007年 | 22篇 |
2006年 | 23篇 |
2005年 | 19篇 |
2004年 | 23篇 |
2003年 | 15篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 10篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1981年 | 15篇 |
1980年 | 4篇 |
1979年 | 11篇 |
1978年 | 6篇 |
1977年 | 15篇 |
1976年 | 11篇 |
1975年 | 14篇 |
1974年 | 7篇 |
1973年 | 6篇 |
1968年 | 2篇 |
1966年 | 2篇 |
1963年 | 2篇 |
1958年 | 3篇 |
排序方式: 共有557条查询结果,搜索用时 15 毫秒
61.
M.J. Singh S.K. Goel R. Shanker D.O. Kataria N. Madhavan P. Sugathan J.J. Das D.K. Avasthi A.K. Sinha 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,4(1):7-13
Measurements were carried out to deduce the transverse kinetic energies of highly charged argon recoil ions produced in single
collisions of 120 MeV ions with argon atoms in which the post collision charge states of the projectiles were not determined. A time of flight
spectrometer was designed and fabricated to detect the charge states of recoils. Experimental procedures for optimizing the
spectrometer for extraction, transmission and detection of recoils are described. A simple approach for determining the transverse
kinetic energy of the recoil ions from FWHM of the peaks is reported. This method is shown to be independent of the choice
of collision partners and requires only the knowledge of the physical values of “optimized parameters” of time-of-flight spectrometer
used in the experiment. The transverse kinetic energy of the recoil ions determined from the present approach is found to
vary from 0.03 eV for to 4.02 eV for Ar10+. These values are compared with the results reported by earlier workers and are shown to follow a q2-behaviour up to a charge state q
=8+ of the recoil ions.
Received: 5 February 1998 / Revised: 8 June 1998 / Accepted: 11 June 1998 相似文献
62.
C. V. Chaudhari K. A. Dubey Y. K. Bhardwaj Virendra Kumar N. K. Goel S. Sabharwal 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):47-53
Radiation induced grafting of acrylonitrile (ACN) on ethylene-propene diene terpolymer (EPDM) rubber film was investigated
by mutual radiation grafting technique. Effect of experimental variables viz. radiation dose, dose rate, type of solvent and
monomer content on extent of grafting was studied. From the kinetic studies a mathematical relation R
g
α[M]0.7
D
0.68 showing non-linear relationship for rate of grafting with monomer concentration and dose was deduced. The grafted samples
showed increased hardness and oil resistance. 相似文献
63.
The extraction of cadmium(II), indium(III) and thallium(III) with high molecular weight amines have been studied from aqueous hydrochloric acid solutions. Using the data mutual binary separations of these three elements with high separation coefficients are proposed. Various variables like type of amine, amine concentration and organic diluent were explored to propose the best conditions of separations. 相似文献
64.
J.-C. Alder H. Behrens F.W. Brasse W. Fehrenbach J. Gayler S.P. Goel R. Haidan V. Korbel J. May M. Merkwitz 《Nuclear Physics B》1975,99(1):1-12
Results on the reaction ep→e′nπ+ are presented in the mass range 1.355 ?W ?1.775 GeV at q2=1GeV2 and in the range 1.415 ? W ? 1.595 GeV at q2=0.6 GeV2. From the angular distribution of the π+ meson the polarization terms σu + ?σL, σp and σI have been determined in the range of production angles 0 <θπ+ ?63° 相似文献
65.
D. B. Parihar Om Prakash Indira Bajaj R. P. Tripathi K. K. Verma 《Mikrochimica acta》1971,59(3):393-398
Summary High explosives having the sameR
f
values on a thin-layer chromatogram and difficult to separate are readily resolved as their coloured -complexes with aromatic amines. After liberation from their complexes on the plate, up to 1.5 g of the explosives can be conveniently estimated at their characteristic absorption maxima.
Zusammenfassung Hochexplosive Substanzen mit gleichenR f -Werten auf Dünnschichtchromatogrammen, die sich schlecht trennen lassen, werden als gefärbte -Komplexe mit aromatischen Aminen gut voneinander getrennt. Nach Freisetzung aus den Komplexen auf der Platte können bis zu 1,5 g der Explosivstoffe bei ihrem charakteristischen Absorptionsmaximum auf übliche Weise bestimmt werden.相似文献
66.
67.
Summary The influence of ultrasonic waves at 1 MC/sec and 225 watts/cm2 power on the negatively charged manganese dioxide sol has been investigated in an atmosphere of nitrogen and thereby excluding
oxygen. The stability of the sol on exposure to ultrasonic waves is affected in a similar way as in presence of air but the
extent to which the sol gets unstable on exposure is less in the absence of oxygen than in its presence. The specific conductivity
increases but hydrogen ion concentration remains practically constant as the time of exposure increases.
The authors are thankful to the Council of Scientific and Industrial Research for the award of scholarship for this work. 相似文献
Zusammenfassung Der Einflu? von Ultraschall (1 mHz, 225 W/cm2) auf negativ geladenes Mangandioxidsol wurde unter Stickstoff unter Ausschlu? von Sauerstoff untersucht. Die Stabilit?t des Sols ist in gleicher Weise wie bei Gegenwart von Luft ver?ndert, nur wird das Sol bei Ausschlu? von Sauerstoff weniger instabil. Die spezifische Leitf?higkeit steigt mit steigender Expositionszeit, w?hrend die Wasserstoffionenkonzentration praktisch konstant bleibt.
The authors are thankful to the Council of Scientific and Industrial Research for the award of scholarship for this work. 相似文献
68.
69.
We have measured the near-normal incidence reflectivity of single crystal RuO2 (rutile) for 6 -axis and ⊥ -axis at room temperature in the photon energy range 0.5 – 9.5 eV. From a Kramers-Kronig analysis of the reflectivity we have obtained the spectral dependence of the real, ?1(ω), and imaginary, ?2(ω), parts of the complex dielectric constant. Comparison with recent band structure and density of states calculations and past experimental studies of related solids has enabled us to gain further insight into the nature of the oxygen -electrons and metal -electrons in this material. 相似文献
70.
Palladium (II) catalyzed cleavage of phenyl-antimony and phenyl-phosphorus groups of Ph3Sb and Ph3P under carbon-dioxide or CO/NO atmosphere leading to benzoic acid, has been demonstrated. 相似文献