全文获取类型
收费全文 | 9137篇 |
免费 | 827篇 |
国内免费 | 10篇 |
学科分类
工业技术 | 9974篇 |
出版年
2024年 | 35篇 |
2023年 | 140篇 |
2022年 | 113篇 |
2021年 | 325篇 |
2020年 | 270篇 |
2019年 | 270篇 |
2018年 | 346篇 |
2017年 | 354篇 |
2016年 | 464篇 |
2015年 | 419篇 |
2014年 | 544篇 |
2013年 | 988篇 |
2012年 | 858篇 |
2011年 | 645篇 |
2010年 | 468篇 |
2009年 | 467篇 |
2008年 | 490篇 |
2007年 | 424篇 |
2006年 | 391篇 |
2005年 | 244篇 |
2004年 | 225篇 |
2003年 | 194篇 |
2002年 | 192篇 |
2001年 | 121篇 |
2000年 | 118篇 |
1999年 | 86篇 |
1998年 | 68篇 |
1997年 | 71篇 |
1996年 | 61篇 |
1995年 | 60篇 |
1994年 | 62篇 |
1993年 | 51篇 |
1992年 | 38篇 |
1991年 | 30篇 |
1990年 | 18篇 |
1989年 | 19篇 |
1988年 | 21篇 |
1987年 | 10篇 |
1986年 | 16篇 |
1985年 | 22篇 |
1984年 | 22篇 |
1983年 | 14篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1980年 | 16篇 |
1979年 | 23篇 |
1978年 | 10篇 |
1974年 | 9篇 |
1973年 | 11篇 |
1947年 | 9篇 |
排序方式: 共有9974条查询结果,搜索用时 0 毫秒
1.
Astrid Labidi Marie-Christine Salon Alessandro Gandini Hervé Cheradame 《Polymer Bulletin》1985,14(3-4):271-278
Summary 2-Furyl vinyl ketone was polymerised using anionic, cationic and free-radical initiators. Yields and molecular weights varied with the type of activation. Whereas radical polymerisation gave a product possessing a regular vinylic structure, other kinds of units were detected in the polymers prepared with anionic and cationic catalysts. 相似文献
2.
We compare two link analysis ranking methods of web pages in a site. The first, called Site Rank, is an adaptation of PageRank to the granularity of a web site and the second, called Popularity Rank, is based on the frequencies of user clicks on the outlinks in a page that are captured by navigation sessions of users through
the web site. We ran experiments on artificially created web sites of different sizes and on two real data sets, employing
the relative entropy to compare the distributions of the two ranking methods. For the real data sets we also employ a nonparametric
measure, called Spearman's footrule, which we use to compare the top-ten web pages ranked by the two methods. Our main result
is that the distributions of the Popularity Rank and Site Rank are surprisingly close to each other, implying that the topology
of a web site is very instrumental in guiding users through the site. Thus, in practice, the Site Rank provides a reasonable
first order approximation of the aggregate behaviour of users within a web site given by the Popularity Rank. 相似文献
3.
Sebastián López Gustavo M. Callicó Félix Tobajas Valentín de Armas José F. López Roberto Sarmiento 《ETRI Journal》2008,30(6):862-864
This letter presents a novel approach for organizing computational resources into groups within H.264/AVC motion estimation architectures, leading to reductions of up to 75% in the equivalent gate count with respect to state‐of‐the‐art designs. 相似文献
4.
5.
6.
The first stages of nickel electrodeposition on amorphous carbon and polycrystalline silver substrates have been studied under galvanostatic conditions. An island growth mode is observed on the two types of substrate. For equivalent conditions the cluster density is higher on silver substrates than on carbon substrates. Dissolution of some nickel clusters is observed a short time after the onset of electrolysis on carbon substrates. This is confirmed by the evolution of the current efficiency and the evolution of the metal surface cluster density as a function of the quantity of electricity. 相似文献
7.
8.
9.
Rui A. S. Lapa José L. F. C. Lima 《Journal of Automated Methods and Management in Chemistry》1991,13(3):119-122
The construction of a microcomputer-controlled electrode switch for
use in potentiometric determinations is described. This can be coupled to most of the analytical equipment usually found in laboratories, to enable a setting up of automatic systems capable of performing sequential determinations with several ion-selective
electrodes. The assessment of its analytical usage and behaviour are discussed. 相似文献
10.
André Girard Pierre Dominique Lansard Bernard Liau Anne Marie Mongeon Jean Luc Thibault 《电信纪事》1991,46(5-6):335-350
Classical hierarchical routing in telephone networks is extended to a wider class called out-of-chain routing in such a way that some useful properties of hierarchical routing are retained. This new routing pattern offers more potential paths than the fixed hierarchical one and can be introduced as a dynamic routing where the fixed alternate sequences change at some predetermined instants during the day. The effect of this new routing pattern on the network performances is examined. The main topic of this paper is to present heuristic methods used to optimise such routings in large networks. We show on artificial networks that the throughput of a given network can be significantly improved by suitable routing choices. We demonstrate that the integration of routing changes within a multihour dimensioning process is possible but the lack of realistic data does not permit at this time to quantify the value of routing optimization on real networks. 相似文献