全文获取类型
收费全文 | 479篇 |
免费 | 13篇 |
专业分类
化学 | 227篇 |
晶体学 | 9篇 |
力学 | 32篇 |
数学 | 45篇 |
物理学 | 179篇 |
出版年
2022年 | 3篇 |
2020年 | 6篇 |
2019年 | 10篇 |
2017年 | 16篇 |
2016年 | 11篇 |
2015年 | 4篇 |
2014年 | 18篇 |
2013年 | 48篇 |
2012年 | 15篇 |
2011年 | 17篇 |
2010年 | 20篇 |
2009年 | 16篇 |
2008年 | 22篇 |
2007年 | 18篇 |
2006年 | 10篇 |
2005年 | 17篇 |
2004年 | 4篇 |
2003年 | 12篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1997年 | 4篇 |
1996年 | 9篇 |
1995年 | 13篇 |
1994年 | 6篇 |
1993年 | 13篇 |
1992年 | 7篇 |
1991年 | 13篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 10篇 |
1986年 | 13篇 |
1985年 | 7篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1969年 | 4篇 |
1967年 | 4篇 |
1959年 | 2篇 |
排序方式: 共有492条查询结果,搜索用时 15 毫秒
131.
P. Tiwari U. P. Deshpande F. Mazaleyrat B. Rachiy 《Molecular Crystals and Liquid Crystals》2020,699(1):39-50
AbstractHoney green synthesis of CoCrxFe2?xO4 (x?=?0.0???1.0) ferrites with increasing Cr content was done by sol-gel auto-combustion method, without any post-preparation thermal treatment. Nanocrystalline nature (grain diameter range between 12.2?nm and 27.9?nm) of the studied samples is confirmed by X-ray diffraction (XRD) data. Observed modification of magnetic properties can be understood in terms of Cr addition induced changes in degree of inversion, modification of disorder affecting A–A, A–B, B–B interaction, re-distribution of cations on A, B sites in the spinel lattice. Grain size (D)-dependent coercivity (Hc) shows that the studied samples lie in the region with overlap between single- and multi-domain regions. Achieved magnetic properties in the studied honey green synthesized samples have significance for self-regulating hyperthermia applications. Results as well reveal modification of bandgap, and would be of use for applications, where minor bandgap tuning is required. Antistructure modeling provides information on the types of surface-active centers. 相似文献
132.
133.
Banerjee Ananya Sane Ramesh T. Mangaonkar Kiran Shailajan Sunita Deshpande Abhijeet Gundi Gunesh 《平面色谱法杂志一现代薄层色谱法》2006,19(1):68-72
JPC – Journal of Planar Chromatography – Modern TLC - A sensitive, simple, and accurate high-performance thin-layer chro-matographic method has been established for determination of... 相似文献
134.
V.P.S. Awana S. Balamurugan A. Deshpande H. Kishan A.V. Narlikar 《Solid State Communications》2006,138(9):452-456
We carefully studied the nonsuperconducting sample of the magneto-superconducting RuSr2(Eu1−xCex)Cu2O10−δ series with composition RuSr2EuCeCu2O10−δ. This compound seems to exhibit a complex magnetic state as revealed by host of techniques like resistivity, thermopower, magnetic susceptibility, and MR measurements. The studied compound exhibited ferromagnetic like M(H) loops at 5, 20, and 50 K, and semiconductor like electrical conduction down to 5 K, with −MR7 T of up to 4% at low temperatures. The −MR7 T decreases fast above 150 K and monotonically becomes close to zero above say 230 K. Below, 150 K −MR7 T decreases to around 3% monotonically down to 75 K, with further increase to 4% at around 30 K and lastly having a slight decrease below this temperature. The thermopower S(T) behavior closely followed the −MR7 T steps in terms of d(S/T)/dT slopes. Further, both MR7 T steps and d(S/T)/dT slopes are found in close vicinity to various magnetic ordering temperatures (Tmag) of this compound. 相似文献
135.
Abhay Deshpande 《Pramana》2003,61(5):859-864
In 2001–2002 the relativistic heavy-ion collider (RHIC) at the Brookhaven National Laboratory (BNL) was first commissioned
for polarized proton collisions. Polarized protons were injected into the RHIC, accelerated to 100 GeV, stored and the two
beams were made to collide in four interaction regions. I will review the progress made by the RHIC spin program, followed
by the physics goals for the next few years. After that I will present a brief overview of a proposal to build a high intensity
polarized electron/positron beam facility at BNL which would enable deep inelastic scattering (DIS) experiments to be pursued
at BNL by its collisions with the RHIC hadron beams. 相似文献
136.
137.
M.P. Joshi S. Raj Mohan T.S. Dhami B. Jain M.K. Singh H. Ghosh T. Shripathi U.P. Deshpande 《Applied Physics A: Materials Science & Processing》2008,90(2):351-358
We report UV-light-induced photodegradation of N,N’-diphenyl-N,N’-bis(3-methylphenyl)-1,1’-biphenyl-4,4’ diamine (TPD) dye.
When a halomethane solution of TPD is exposed to UV light it first oxidizes TPD and subsequently with further exposure leads
to irreversible transformation of TPD to an acridine derivative as photoproduct. Exclusive use of halomethane solvents like
chloroform and dichloromethane suggests solvent radical initiated photochemical transformation of TPD to a stable acridine-based
photoproduct. The resultant photoproduct of TPD showed broad-band dual (both blue and green) emissions in various solvents
and also from the sublimed thin film. Based on solvent- and concentration-dependent photoluminescence (PL) of the photoproduct,
PL excitation and lifetimes of blue and green bands, the origin of emission in the green region is due to an intermolecular
excimer/aggregate of acridine-based photoproduct. A film of acridine-based photoproduct dispersed in polystyrene also showed
substantial improvement in electrical conductivity compared to the parent compound TPD. The technique of UV-light-induced
molecule structure transformation and material processing under specific environmental conditions may be considered as an
efficient means of obtaining materials with enhanced optoelectronic properties.
PACS 61.82.Pv; 72.80.Le; 82.50.-m; 82.30.Lp; 33.50.-j 相似文献
138.
W.?BehrEmail author N.?G.?Deshpande G.?Duplancic P.?Schupp J.?Trampetic J.?Wess 《The European Physical Journal C - Particles and Fields》2003,29(3):441-446
On non-commutative spacetime, the standard model (SM) allows new, usually SM forbidden, triple gauge boson interactions to
occur. In this letter we propose the SM strictly forbidden
and
decay modes coming from the gauge sector of the non-commutative standard model (NCSM) as a place where non-commutativity
could be experimentally discovered.
Received: 2 July 2002, Revised: 28 February 2003, Published online: 18 June 2003 相似文献
139.
Wise S Quetschke V Deshpande AJ Mueller G Reitze DH Tanner DB Whiting BF Chen Y Tünnermann A Kley E Clausnitzer T 《Physical review letters》2005,95(1):013901
Diffraction gratings affect the absolute phase of light in a way that is not obvious from the usual derivation of optical paths using the grating equation. For example, consider light which encounters first one and then the second of two parallel gratings. If one grating is moved parallel to its surface, the phase of the light diffracted from the grating pair is shifted by 2pi each time the grating is moved by one grating constant, even though the geometric path length is not altered by the motion. This additional phase shift must be included when incorporating diffraction gratings in interferometers. 相似文献
140.
Manoj Kumar Anant Deshpande Chintan Gupta A. K. Nath 《Journal of Chemical Sciences》2003,115(3):219-224
Multi-photon dissociation of Freon-22 (CF2HC1) at low temperatures has been carried out to separate the C-13 isotope using a TEA CO2 laser. Yield and enrichment of C-13 isotope in the product C2F4 are studied at 9P(22) laser line as a function of temperature (−50°C to 30°C). It is observed that at a given fluence when the temperature
is lowered the yield decreases and the enrichment factor of C-13 increases.
Room temperature irradiation of CF2HC1 towards the blue edge of C-13 absorption (i.e. at 9P(20) laser line) gives low yield of the product (C2F4) at a fluence, which produces the desired enrichment factor of 100. An increase in fluence gives very high yield of C2F4 but the enrichment factor is very low. Irradiating CF2HC1 at a temperature of −10°C enhances the enrichment factor to 100 and the yield obtained is comparable to that towards the
red edge of C-13 absorption (i.e. at 9P(26) laser line).
At a given enrichment factor higher enrichment efficiency is achieved when CF2HC1 is irradiated at lower temperature. 相似文献