全文获取类型
收费全文 | 1866篇 |
免费 | 28篇 |
国内免费 | 8篇 |
专业分类
化学 | 1022篇 |
晶体学 | 11篇 |
力学 | 62篇 |
数学 | 448篇 |
物理学 | 359篇 |
出版年
2021年 | 11篇 |
2019年 | 16篇 |
2016年 | 31篇 |
2015年 | 18篇 |
2014年 | 36篇 |
2013年 | 94篇 |
2012年 | 52篇 |
2011年 | 53篇 |
2010年 | 48篇 |
2009年 | 32篇 |
2008年 | 75篇 |
2007年 | 71篇 |
2006年 | 61篇 |
2005年 | 84篇 |
2004年 | 59篇 |
2003年 | 49篇 |
2002年 | 45篇 |
2001年 | 51篇 |
2000年 | 42篇 |
1999年 | 16篇 |
1998年 | 23篇 |
1997年 | 21篇 |
1996年 | 36篇 |
1995年 | 25篇 |
1994年 | 36篇 |
1993年 | 29篇 |
1992年 | 32篇 |
1991年 | 23篇 |
1990年 | 32篇 |
1989年 | 32篇 |
1988年 | 28篇 |
1987年 | 34篇 |
1986年 | 22篇 |
1985年 | 45篇 |
1984年 | 23篇 |
1983年 | 28篇 |
1982年 | 35篇 |
1981年 | 28篇 |
1980年 | 28篇 |
1979年 | 34篇 |
1978年 | 22篇 |
1977年 | 30篇 |
1976年 | 16篇 |
1975年 | 28篇 |
1974年 | 34篇 |
1973年 | 27篇 |
1972年 | 17篇 |
1971年 | 14篇 |
1969年 | 13篇 |
1968年 | 12篇 |
排序方式: 共有1902条查询结果,搜索用时 9 毫秒
1.
Thorsten Brand Kyle Ratinac Jeffrey V. Castro Robert G. Gilbert 《Journal of polymer science. Part A, Polymer chemistry》2004,42(22):5706-5713
A method was developed for free‐radical polymerization in the confines of a hollow latex particle. Hollow particles were prepared via the dynamic swelling method from polystyrene seed and divinylbenzene and had hollows of 500–1000 nm. So that these hollow poly(divinylbenzene) particles could function as submicrometer reactors, the particles were filled with a monomer (N‐isopropylacrylamide) via the dispersion of the dried particles in the molten monomer. The monomer that was not contained in the hollows was removed by washing and gentle abrasion. Free‐radical polymerization was then initiated by γ radiolysis in the solid state. Transmission electron microscopy showed that poly(N‐isopropylacrylamide) formed in the hollow interior of the particles, which functioned as submicrometer reactors. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5706–5713, 2004 相似文献
2.
Przemyslaw Bogacki Stanley Weinstein Yuesheng Xu 《Advances in Computational Mathematics》1997,7(4):593-621
We consider the choice of a functional to measure the distance between two parametric curves. We identify properties of such
a distance functional that are important for geometric design. Several popular definitions of distance are examined, and new
functionals are presented which satisfy the desired properties.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
Franck D'Agosto Marie‐Thrse Charreyre Christian Pichot Robert G. Gilbert 《Journal of polymer science. Part A, Polymer chemistry》2003,41(9):1188-1195
A method is described for synthesizing latex particles with anchored hairs by the grafting of hydrophilic chains, synthesized by reversible addition–fragmentation chain transfer, onto functionalized latex particles. These have the potential to bind biologically active species. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1188–1195, 2003 相似文献
4.
K A Dowsland M Gilbert G Kendall 《The Journal of the Operational Research Society》2007,58(4):429-438
This paper is concerned with the development of a customized circle packing algorithm for a manufacturer of sprockets for the motor cycle industry. Practical constraints mean that the problem differs somewhat from those tackled elsewhere in the literature. In particular, the layouts need to conform to a given structure. This is achieved by using a local search algorithm with an appropriate starting solution and a series of neighbourhoods designed to preserve the layout structure. Empirical evidence based on real data shows that the quality of the resulting solutions closely matches that of cutting patterns currently produced by human experts. Computation times average around 20–30?s per order as compared to several hours for an equivalent manual solution. 相似文献
5.
6.
The purpose of the present study was to describe the effects ofacute laryngitis on some aerodynamic, acoustic, and perceptual measures. Eleven subjects with diagnosed acute laryngitis due to upper respiratory infection were recorded during a laryngitic episode and 1 week to 10 days after amelioration of the laryngitic condition. Fundamental frequency values, collapsed across the five vowels, were significantly reduced in the laryngitic compared with the normal speaking condition. The decrease in fundamental frequency associated with acute laryngitis suggests an increase in the mass of the vocal folds. In addition, aerodynamic values differed significantly for the laryngitic condition compared with the normal speaking condition, suggesting the presence of laryngeal hypofunction. Perceptual data indicated that speakers in the laryngitic condition were judged to have a hoarse voice when compared with the normal speaking condition. 相似文献
7.
Robert Carroll George Delic R. P. Gilbert 《Mathematical Methods in the Applied Sciences》1989,11(1):43-63
It is shown how Newton–Sabatier methods (arising in inverse scattering at fixed energy) can be related to spectral measures and typically when they correspond to regular potentials. A number of spectral formulae for various transmutation kernels are also given in terms of general Kontorovi?–Lebedev theory and connections to generating functions, generalized orthogonal polynomials, etc. are indicated. 相似文献
8.
9.
It is generally in a firm’s interest for its supply chain partners to invest in innovations. To the extent that these innovations either reduce the partners’ variable costs or stimulate demand for the end product, they will tend to lead to higher levels of output for all of the firms in the chain. However, in response to the innovations of its partners, a firm may have an incentive to opportunistically increase its own prices. The possibility of such opportunistic behavior creates a hold-up problem that leads supply chain partners to underinvest in innovation. Clearly, this hold-up problem could be eliminated by a pre-commitment to price. However, by making an advance commitment to price, a firm sacrifices an important means of responding to demand uncertainty. In this paper we examine the trade-off that is faced when a firm’s channel partner has opportunities to invest in either cost reduction or quality improvement, i.e. demand enhancement. Should it commit to a price in order to encourage innovation, or should it remain flexible in order to respond to demand uncertainty. We discuss several simple wholesale pricing mechanisms with respect to this trade-off. 相似文献
10.
Gilbert Strang 《Physica D: Nonlinear Phenomena》1992,60(1-4):239-244
The construction of wavelets begins with a dilation equation (x) = Σck(2x-k). The choice of the coefficients ck controls the accuracy and orthogonality of wavelet expansions. We show how the Daubechies coefficients, which give pth order accuracy with 2p coefficients (the minimum number), follow from orthogonality and accuracy conditions applied to the polynomial Σckeikξ. 相似文献