全文获取类型
收费全文 | 223960篇 |
免费 | 1726篇 |
国内免费 | 530篇 |
专业分类
化学 | 104702篇 |
晶体学 | 3391篇 |
力学 | 10271篇 |
综合类 | 10篇 |
数学 | 21829篇 |
物理学 | 64509篇 |
无线电 | 21504篇 |
出版年
2021年 | 2159篇 |
2020年 | 2248篇 |
2019年 | 2876篇 |
2018年 | 3969篇 |
2017年 | 3961篇 |
2016年 | 5208篇 |
2015年 | 2476篇 |
2014年 | 4680篇 |
2013年 | 9205篇 |
2012年 | 7255篇 |
2011年 | 8509篇 |
2010年 | 6959篇 |
2009年 | 7377篇 |
2008年 | 8490篇 |
2007年 | 8548篇 |
2006年 | 7618篇 |
2005年 | 6853篇 |
2004年 | 6473篇 |
2003年 | 5967篇 |
2002年 | 5899篇 |
2001年 | 6382篇 |
2000年 | 4889篇 |
1999年 | 3862篇 |
1998年 | 3321篇 |
1997年 | 3389篇 |
1996年 | 3062篇 |
1995年 | 2738篇 |
1994年 | 2817篇 |
1993年 | 2713篇 |
1992年 | 3004篇 |
1991年 | 3120篇 |
1990年 | 3048篇 |
1989年 | 3066篇 |
1988年 | 2926篇 |
1987年 | 2770篇 |
1986年 | 2620篇 |
1985年 | 3312篇 |
1984年 | 3327篇 |
1983年 | 2792篇 |
1982年 | 2711篇 |
1981年 | 2653篇 |
1980年 | 2463篇 |
1979年 | 2807篇 |
1978年 | 2772篇 |
1977年 | 2947篇 |
1976年 | 2953篇 |
1975年 | 2736篇 |
1974年 | 2671篇 |
1973年 | 2793篇 |
1972年 | 2138篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Physics of Particles and Nuclei Letters - Resonance structure of the beta decay strength function Sβ(E) for GT β–-decay of halo nuclei 6He and 11Li is analyzed. Compare experimental... 相似文献
53.
An N. Le Ruiqi Liang Prof. Dr. Mingjiang Zhong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(35):8177-8189
Mixed-graft block copolymers (mGBCPs) consist of two or more types of polymeric side chains grafted on a linear backbone in a random, alternating, or pseudo-alternating sequence. They can phase-separate with the backbone serving as the interface of the blocks, and the side chains dominate their self-assembly behavior. mGBCPs are an accessible polymer architecture for exploring the idea of encoding polymer properties through the macromolecular architecture, as there are two distinct structural components that can be tuned: the backbone and the side chains. In this Concept article, the current literature on the synthesis of mGBCPs is reviewed, and the advantages and disadvantages of each synthetic method are noted. The self-assembly of mGBCPs is also discussed where possible. Finally, directions for future research on mGBCP synthesis and self-assembly are suggested. 相似文献
54.
Anfimov N. V. Vorobel V. Kovalev Yu. S. Kodyš P. 《Physics of Particles and Nuclei Letters》2019,16(6):820-825
Physics of Particles and Nuclei Letters - The Silicon Photomultiplier (SiPM) is a novel semiconducting photodetector which can detect single photons. It consists of many microcells (pixels)... 相似文献
55.
56.
57.
58.
Co-browsing is an activity in which a group of users navigate their way through of a set of Web pages together for a shared
purpose. Effective co-browsing among users with different device capabilities requires a shared understanding of those Web
pages. This paper demonstrates the concept of shared viewpoints (SVPs), and personal viewpoints (PVPs), for co-browsing, before
detailing a framework for implementing these concepts. Finally, the effectiveness of the framework is presented through a
perceptual experiment. 相似文献
59.
Note on B-splines, wavelet scaling functions, and Gabor frames 总被引:3,自引:0,他引:3
Grochenig K. Janssen A.J.E.M. Kaiblinger N. Pfander G.E. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2003,49(12):3318-3320
Let g be a continuous, compactly supported function on such that the integer translates of g constitute a partition of unity. We show that the Gabor system (g,a,b), with window g and time-shift and frequency-shift parameters a,b>0 has no lower frame bound larger than 0 if b=2,3,... and a>0. In particular, (g,a,b) is not a Gabor frame if g is a continuous, compactly supported wavelet scaling function and if b=2,3,... and a>0. We give an example for our result for the case that g=B/sub 1/, the triangle function supported by [-1,1], by showing pictures of the canonical dual corresponding to (g,a,b) where ab=1/4 and b crosses the lines N=2,3,. 相似文献
60.
de Oliveira J.C. Hosseini M. Shirmohammadi S. Malric F. Nourian S. El Saddik A. Georganas N.D. 《Multimedia, IEEE》2003,10(3):18-29
Using Java-based tools in multimedia collaborative environments accessed over the Internet can increase an application's client base. Most operating systems support Java, and its "compile once-run everywhere" architecture is easy to maintain and update. The Java-based tools presented here let users share Internet resources, including resources originally designed for single use. 相似文献