全文获取类型
收费全文 | 12938篇 |
免费 | 328篇 |
国内免费 | 93篇 |
专业分类
化学 | 8474篇 |
晶体学 | 119篇 |
力学 | 326篇 |
综合类 | 1篇 |
数学 | 1765篇 |
物理学 | 2674篇 |
出版年
2022年 | 83篇 |
2021年 | 101篇 |
2020年 | 176篇 |
2019年 | 145篇 |
2018年 | 104篇 |
2017年 | 118篇 |
2016年 | 252篇 |
2015年 | 193篇 |
2014年 | 250篇 |
2013年 | 572篇 |
2012年 | 628篇 |
2011年 | 771篇 |
2010年 | 375篇 |
2009年 | 309篇 |
2008年 | 695篇 |
2007年 | 671篇 |
2006年 | 636篇 |
2005年 | 643篇 |
2004年 | 612篇 |
2003年 | 448篇 |
2002年 | 450篇 |
2001年 | 226篇 |
2000年 | 211篇 |
1999年 | 130篇 |
1998年 | 139篇 |
1997年 | 144篇 |
1996年 | 226篇 |
1995年 | 157篇 |
1994年 | 163篇 |
1993年 | 200篇 |
1992年 | 167篇 |
1991年 | 135篇 |
1990年 | 132篇 |
1989年 | 133篇 |
1988年 | 126篇 |
1987年 | 111篇 |
1986年 | 112篇 |
1985年 | 185篇 |
1984年 | 185篇 |
1983年 | 124篇 |
1982年 | 169篇 |
1981年 | 160篇 |
1980年 | 148篇 |
1979年 | 129篇 |
1978年 | 163篇 |
1977年 | 158篇 |
1976年 | 123篇 |
1975年 | 110篇 |
1974年 | 117篇 |
1973年 | 107篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Liquid crystal televisions have been employed as spatial light modulators in a variety of optical image processing applications. We have used such devices to develop techniques in speckle metrology for the electronic addition of speckle patterns and the display of speckle correlation, and also for the real-time display of object motion. Factors which affect the performance in terms of the useful working range and the accuracy of displacement measurement are discussed. Some modifications to the LCTV which should increase the potential of these devices as spatial light modulators, when used in both amplitude and phase modulation, are considered briefly. 相似文献
62.
We study computable trees with distinguished initial subtree (briefly, I-trees). It is proved that all I-trees of infinite height are computably categorical, and moreover, they all have effectively infinite computable dimension. 相似文献
63.
64.
65.
Francis J. Narcowich Joseph D. Ward Holger Wendland. 《Mathematics of Computation》2005,74(250):743-763
In this paper we discuss Sobolev bounds on functions that vanish at scattered points in a bounded, Lipschitz domain that satisfies a uniform interior cone condition. The Sobolev spaces involved may have fractional as well as integer order. We then apply these results to obtain estimates for continuous and discrete least squares surface fits via radial basis functions (RBFs). These estimates include situations in which the target function does not belong to the native space of the RBF.
66.
In this paper a new proof of an identity of Giacomin, Olla, and Spohn is given. The identity relates the 2 point correlation function of a Euclidean field theory to the expectation of the Green's function for a pde with random coefficients. The Euclidean field theory is assumed to have convex potential. An inequality of Brascamp and Lieb therefore implies Gaussian bounds on the Fourier transform of the 2 point correlation function. By an application of results from random pde, the previously mentioned identity implies pointwise Gaussian bounds on the 2 point correlation function. 相似文献
67.
We solve a bitangential interpolation problem for contractive multipliers
on the Arveson space with an arbitrary interpolating set in the closed
unit ball . The solvability criterion is established in terms of positive
kernels. The set of all solutions is parametrized by a Redheffer transform.
Submitted: February 2, 2002. 相似文献
68.
Martin R. Bridson Charles F. Miller III 《Proceedings of the American Mathematical Society》2004,132(1):59-65
We give examples of direct products of three hyperbolic groups in which there cannot exist an algorithm to decide which finitely presented subgroups are isomorphic.
69.
70.
Anita M. R. Fisher Kathleen Danenberg Debabrata Banerjee Joseph R. Bertino Peter Danenberg Charles J. Gomer 《Photochemistry and photobiology》1997,66(2):265-270
Loss of p53 function has been correlated with decreased sensitivity to chemotherapy and radiation therapy in a variety of human tumors. Comparable analysis of p53 status with sensitivity to oxidative stress induced by pho-todynamic therapy has not been reported. In the current study we examined photosensitivity in human promye-locytic leukemia HL60 cells exhibiting either wild-type p53, mutated p53 or deleted p53 expression. Experiments were performed using a purpurin, tin ethyl etiopurpurin (SnET2)-, or a porphyrin, Photofrin (PH)-based photo-sensitizer. Total SnET2 accumulation was comparable in all three cell lines. Uptake of PH was highest in cells expressing wild-type p53 but incubation conditions could be adjusted to achieve equivalent cellular PH levels during experiments that analyzed photosensitivity. Survival measurements demonstrated that HL60 cells expressing wild-type p53 were more sensitive to PH- and SnET2-mediated photosensitization, as well as to UVC irradiation, when compared to HL60 cells exhibiting deleted or mutated p53 phenotypes. A rapid apoptotic response was observed following purpurin- and porphyrin-induced photosensitization in all cell lines. Results of this study indicate that photosensitivity is increased in HL60 cells expressing wild-type p53 and that photosensitizer-medi-ated oxidative stress can induce apoptosis through a p53-independent mechanism in HL60 cells . 相似文献