全文获取类型
收费全文 | 970篇 |
免费 | 28篇 |
国内免费 | 1篇 |
专业分类
化学 | 686篇 |
晶体学 | 17篇 |
力学 | 31篇 |
数学 | 78篇 |
物理学 | 187篇 |
出版年
2024年 | 3篇 |
2023年 | 14篇 |
2022年 | 28篇 |
2021年 | 28篇 |
2020年 | 34篇 |
2019年 | 33篇 |
2018年 | 33篇 |
2017年 | 36篇 |
2016年 | 48篇 |
2015年 | 28篇 |
2014年 | 45篇 |
2013年 | 89篇 |
2012年 | 73篇 |
2011年 | 87篇 |
2010年 | 36篇 |
2009年 | 33篇 |
2008年 | 49篇 |
2007年 | 40篇 |
2006年 | 42篇 |
2005年 | 36篇 |
2004年 | 34篇 |
2003年 | 21篇 |
2002年 | 17篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 4篇 |
1997年 | 5篇 |
1996年 | 10篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1981年 | 11篇 |
1978年 | 3篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1967年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有999条查询结果,搜索用时 15 毫秒
1.
Journal of Thermal Analysis and Calorimetry - In the case of flow boiling, the prediction of vapour fraction in the horizontal microchannel is a severe issue using the numerical technique.... 相似文献
2.
V Ravindran Pankaj Agrawal Rahul Basu Satyaki Bhattacharya J Blümlein V Del Duca R Harlander D Kosower Prakash Mathews Anurag Tripathi 《Pramana》2006,67(5):983-992
This is the report of the subgroup QCD of Working Group-4 at WHEPP-9. We present the activities that had taken place in the
subgroup and report some of the partial results arrived at following the discussion at the working group meetings. 相似文献
3.
Pankaj Mathur 《分析论及其应用》2006,22(2):105-113
In this paper, we study the explicit representation and convergence of (0, 1;0)-interpolation on infisite interval, which means to determine a polynomial of degree ≤ 3n - 2 when the function values areprescribed at two set of points namely the zeros of Hn(x) and H′n (x) and the first derivatives at the zerosof H′n(x). 相似文献
4.
Pankaj K. Agarwal 《Discrete and Computational Geometry》1990,5(1):533-573
In this paper we present efficient deterministic algorithms for various problems involving lines or segments in the plane, using the partitioning algorithm described in a companion paper [A3]. These applications include: (i) anO(m
2/3
n
2/3 · log2/3
n · log/3 (m/n)+(m+n) logn) algorithm to compute all incidences betweenm points andn lines, where is a constant <3.33; (ii) anO(m
2/3
n
2/3 · log5/3
n · log/3 (m/n)+(m+n) logn) algorithm to computem faces in an arrangement ofn lines; (iii) anO(n
4/3 log(+2)/3
n) algorithm to count the number of intersections in a set ofn segments; (iv) anO(n
4/3 log( + 2)/3
n) algorithm to count red-blue intersections between two sets of segments, and (v) anO(n
3/2 log/3
n) algorithm to compute spanning trees with low stabbing number for a set ofn points. We also present an algorithm that, given set ofn points in the plane, preprocesses it, in timeO(nm log+1/2
n), into a data structure of sizeO(m) forn lognmn
2, so that the number of points ofS lying inside a query triangle can be computed inO((n/m) log3/2
n) time.Work on this paper has been supported by Office of Naval Research Grant N00014-87-K-0129, by National Science Foundation Grant DCR-83-20085, and by grants from the Digital Equipment Corporation and the IBM Corporation. A preliminary version of this paper appears in theProceedings of the 5th ACM Symposium on Computational Geometry, 1989, pp. 11–22. 相似文献
5.
1R,2S,5R,8R; 1R,2S,5R,8S; 1S,2S,5R,8R; and 1S,2S,5R,8S-Iridodials have been prepared in five steps from 4aS,7S,7aR and 4aS,7S,7aS-nepetalactones, major components of catnip oil. 1R,2S,5R,8R-Iridodial has been identified as a male-produced male-aggregation pheromone for Chrysopa oculata, the first pheromone of any kind identified for lacewings. 相似文献
6.
Farukh Arjmand Shamima Parveen Mala Chauhan Shaiba Parveen Sartaj Tabassum 《Transition Metal Chemistry》2006,31(2):237-245
New mononuclear and dinuclear complexes [3-hydroxyethyl-1,3,5,8,11pentaazacyclotridecane]copper(II) (1)/nickel(II) (2) perchlorate and O,O ethane bridged bis-copper(II) (3)/nickel(II) (4) macrocycles have been synthesized and characterized by various spectroscopic techniques, viz. i.r., n.m.r., e.p.r., u.v.–vis. and conductance measurements. Spectral data and conductance measurements reveal that all
the complexes are consistent with square-planar geometry and are ionic in nature. The catalytic activity of the dinuclear
Cu(II) complex (3) in the presence of pyrocatechol was determined spectrometrically by monitoring the increase of the o-benzoquinone characteristic absorption band at 25,000 cm−1 with respect to time in DMF saturated with molecular oxygen. The kinetic parameters Vmax (2.8×10−3 M s−1) and KM (1.4×10−3 mm) have been determined by Michaelis–Menten method. Electrochemistry of the dinuclear Cu(II) complex has been studied in the
presence of molecular oxygen with pyrocatechol and without pyrocatechol at a scan rate of 0.1 V s−1 by cyclic voltammetry. On addition of pyrocatechol, complex shows a shift in Epc, Epa and E1/2 values indicating the oxidation of substrate (pyrocatechol). 相似文献
7.
Bjelopavlic M Singh PK El-Shall H Moudgil BM 《Journal of colloid and interface science》2000,226(1):159-165
Hydrogen bonding is generally thought to be an ubiquitous adsorption mechanism, which often foils selective adsorption schemes. Through investigation of hydrogen bonding energy and its dependence on surface molecular architecture, it may be possible to develop new methodologies to control the adsorption of surfactants and polymeric flocculants, depressants, and dispersants used in particulate processing industries. A model system using St?ber silica spheres and polyethylene oxide, a polymer known for its ability to form hydrogen bonds, was examined. The effect of two different surface treatments of the silica particles, calcination and rehydroxylation, upon the adsorption of two polymer molecular weights was studied. The adsorption behavior was then linked to the respective surface structures via characterization of the surfaces using FTIR, NMR, and Raman techniques. In this paper role of hydrogen bonding sites and surface architecture on adsorption is discussed. Copyright 2000 Academic Press. 相似文献
8.
Moni Chauhan Claude Chuit Robert J. P. Corriu Catherine Rey Jean-Paul Declercq Antoine Dubourg 《Journal of organometallic chemistry》1996,510(1-2):173-179
The X-ray structure analysis of bis(8-dimethylamino-l-naphthyl)phenylphosphane (3) and of the corresponding sulphide 4 has revealed hexacoordination at phosphorus in both cases, the N … P separations being less than the sum of the van der Waal radii. Furthermore, in both cases the overall geometry corresponds to a distorted bicapped tetrahedron. The optimum geometry calculated for 4 via the
program developed by Autodesk (MM + method) suggests that the structure of the molecule is a function not only of steric requirements but also of electronic effects. 相似文献
9.
10.