全文获取类型
收费全文 | 1891篇 |
免费 | 23篇 |
国内免费 | 13篇 |
专业分类
化学 | 945篇 |
晶体学 | 16篇 |
力学 | 35篇 |
数学 | 397篇 |
物理学 | 534篇 |
出版年
2017年 | 15篇 |
2016年 | 19篇 |
2015年 | 28篇 |
2014年 | 32篇 |
2013年 | 123篇 |
2012年 | 49篇 |
2011年 | 87篇 |
2010年 | 42篇 |
2009年 | 46篇 |
2008年 | 72篇 |
2007年 | 85篇 |
2006年 | 71篇 |
2005年 | 93篇 |
2004年 | 52篇 |
2003年 | 62篇 |
2002年 | 50篇 |
2001年 | 40篇 |
2000年 | 29篇 |
1999年 | 25篇 |
1998年 | 26篇 |
1997年 | 25篇 |
1996年 | 33篇 |
1995年 | 35篇 |
1994年 | 32篇 |
1993年 | 30篇 |
1992年 | 25篇 |
1991年 | 20篇 |
1990年 | 14篇 |
1989年 | 30篇 |
1988年 | 30篇 |
1987年 | 27篇 |
1986年 | 34篇 |
1985年 | 49篇 |
1984年 | 39篇 |
1983年 | 25篇 |
1982年 | 36篇 |
1981年 | 29篇 |
1980年 | 29篇 |
1979年 | 27篇 |
1978年 | 28篇 |
1977年 | 26篇 |
1976年 | 41篇 |
1975年 | 23篇 |
1974年 | 25篇 |
1973年 | 21篇 |
1972年 | 13篇 |
1971年 | 11篇 |
1969年 | 11篇 |
1968年 | 11篇 |
1967年 | 12篇 |
排序方式: 共有1927条查询结果,搜索用时 31 毫秒
1.
V. Yu. Baranovskii L. L. Yasina M. V. Motyakin I. I. Aliev S. Shenkov M. Dimitrov N. Lambov A. M. Wasserman 《Polymer Science Series A》2006,48(12):1304-1309
Partially water-swellable polymer networks were synthesized on the basis of poly(acrylic acid) and various macrodiisocyanates. Hydrophilic and hydrophobic local regions were revealed in swollen networks (hydrogels) by means of the spin probe technique. The local mobility in hydrophobic regions depends on the macrodiisocyanate structure; however, it is substantially lower than that in hydrophilic regions for all gels. It was assumed that the presence of hydrophobic and hydrophilic regions and the difference in their local dynamics must have a substantial effect on the pharmacokinetics of release of drugs immobilized in these hydrogels. 相似文献
2.
Ohne Zusammenfassung
übersetzt von H. Kauffmann (Leipzig). 相似文献
3.
Harish C. Bahl Stanley Zionts 《The Journal of the Operational Research Society》1987,38(12):1141-1148
Scheduling the production of several items requires the determination of production quantities in different periods in the presence of resource constraints. Several approximate and heuristic algorithms have been proposed to solve this problem. However, no method for finding an optimal solution has as yet been developed. It is shown that the problem may be solved advantageously using Benders' decomposition. The subproblem in Benders' decomposition is shown to be a transportation problem, and some strategies for solving the master problem are indicated. The paper concludes with a sample problem demonstrating the application of the method. 相似文献
4.
5.
K. Venkatakrishnan B.K.A. Ngoi P. Stanley L.E.N. Lim B. Tan N.R. Sivakumar 《Applied Physics A: Materials Science & Processing》2002,75(4):493-496
Photomasks are the backbone of microfabrication industries. Currently they are fabricated by a lithographic process, which
is very expensive and time consuming since it is a multi-step process. These issues can be addressed by fabricating photomasks
by direct femtosecond laser writing, which is a single-step process and comparatively cheaper and faster than lithography.
In this paper we discuss our investigations on the effect of two types of laser writing techniques, namely front- and rear-side
laser writing, with regard to the feature size and the edge quality of a feature. It is proved conclusively that for the patterning
of masks, front-side laser writing is a better technique than rear-side laser writing with regard to smaller feature size
and better edge quality. Moreover the energy required for front-side laser writing is considerably lower than that for rear-side
laser writing.
Received: 22 May 2001 / Accepted: 14 September 2001 / Published online: 17 October 2001 相似文献
6.
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
7.
A family of infinite measure preserving odometers is presented which exhibit examples ofp-recurrent but notp+1-recurrent ergodic transformations for everyp>1. 相似文献
8.
This paper provides a rigorous proof of the existence of an infinite number of black hole solutions to the Einstein-Yang/Mills equations with gauge groupSU(2), for any event horizon. It is also demonstrated that the ADM mass of each solutions is finite, and that the corresponding Einstein metric tends to the associated Schwarzschild metric at a rate 1/r
2, asr tends to infinity.Research supported in part by the NSF, Contract No. DMS-89-05205Research supported in part by the DE, Contract No. De-FG 02-88 EF 25065 相似文献
9.
D. Ohlberg J.J. Blackstock R. Ragan S. Kim R. Stanley Williams 《Applied Physics A: Materials Science & Processing》2005,80(6):1327-1334
A recently demonstrated [1] in-vacuo template-stripping process is applied to the study of platinum films stripped from ultra-flat silicon-oxide surfaces. Template-stripped (TS) Pt surfaces, prepared with a range of post-deposition annealing times prior to being stripped from the templating surface in an ultra-high vacuum (UHV) environment, are examined by UHV scanning tunneling microscopy (STM). These studies reveal that without post-deposition annealing, TS Pt surfaces are largely made up of poorly-ordered, granular nanostructures undesirable for many applications. The post-deposition annealing treatments explored in the study result in the emergence and continuous growth of large smooth crystallites. Issues with crystallite orientation relative to the TS surface and artefacts arising as a result of the epoxy used in the template-stripping process are presented and discussed in relation to optimizing the template-stripping procedure for specific applications such as self-assembled monolayer (SAM) formation for molecular electronics. PACS 68.37.Ef; 68.47.De; 68.55.Jk; 81.05.Bx; 81.15.Ef 相似文献
10.