全文获取类型
收费全文 | 11010篇 |
免费 | 859篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 85篇 |
综合类 | 8篇 |
化学工业 | 2735篇 |
金属工艺 | 122篇 |
机械仪表 | 333篇 |
建筑科学 | 506篇 |
矿业工程 | 23篇 |
能源动力 | 230篇 |
轻工业 | 2249篇 |
水利工程 | 103篇 |
石油天然气 | 21篇 |
无线电 | 822篇 |
一般工业技术 | 2079篇 |
冶金工业 | 505篇 |
原子能技术 | 25篇 |
自动化技术 | 2036篇 |
出版年
2024年 | 37篇 |
2023年 | 152篇 |
2022年 | 140篇 |
2021年 | 372篇 |
2020年 | 304篇 |
2019年 | 305篇 |
2018年 | 477篇 |
2017年 | 480篇 |
2016年 | 569篇 |
2015年 | 446篇 |
2014年 | 571篇 |
2013年 | 1052篇 |
2012年 | 1013篇 |
2011年 | 908篇 |
2010年 | 575篇 |
2009年 | 538篇 |
2008年 | 602篇 |
2007年 | 548篇 |
2006年 | 431篇 |
2005年 | 313篇 |
2004年 | 298篇 |
2003年 | 248篇 |
2002年 | 237篇 |
2001年 | 136篇 |
2000年 | 134篇 |
1999年 | 90篇 |
1998年 | 82篇 |
1997年 | 85篇 |
1996年 | 70篇 |
1995年 | 65篇 |
1994年 | 67篇 |
1993年 | 55篇 |
1992年 | 39篇 |
1991年 | 30篇 |
1990年 | 20篇 |
1989年 | 24篇 |
1988年 | 24篇 |
1987年 | 13篇 |
1986年 | 19篇 |
1985年 | 28篇 |
1984年 | 28篇 |
1983年 | 18篇 |
1982年 | 21篇 |
1981年 | 24篇 |
1980年 | 16篇 |
1979年 | 26篇 |
1978年 | 13篇 |
1974年 | 9篇 |
1973年 | 11篇 |
1947年 | 9篇 |
排序方式: 共有10000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.
7.
8.
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
9.
Patrícia Carvalho de Souza André Salim Khayat Igor Chamon Seligmann Rommel Mario Rodríguez Burbano 《Biocell》2008,32(2):207-210
The collared peccary (Tayassu tajacu) is widely distributed over the American continent, being found from the south of the USA to the north of Argentina. In Brazil, it is spread all over the country, being one of the potential species to be raised in captivity. Therefore, the cytogenetic techniques could be a potential tool for reproductive monitoring of animals raised in captivity, mainly when destined for commercial purposes. This study had the objective of determining the chromosome number of two populations raised in captivity and characterizing them by GTG banding. For this purpose, an analysis was made of mitotic metaphases obtained from lymphocyte cultures made from blood samples of 11 animals, six of which from the Northeast and five from the North of Brazil. The results of this analysis showed the same karyotype pattern for the species (2n=30 chromosomes and NF=48), besides corresponding to the South American pattern of the species, i.e., without a translocation between autosomes 1 and 8, chromosome X acrocentric, and no differences were found between the two populations studied. However, chromosomal polymorphisms were observed compared to data from the literature on populations from North and South America. 相似文献
10.
Michael Rabinovich Kate L. Olsavsky Burr Leach Mauricio Cabrera‐Ríos José M. Castro 《应用聚合物科学杂志》2008,109(4):2465-2471
Sheet molding compound (SMC) is a fiber‐reinforced polymeric composite. It is often used in automotive, marine, and industrial applications over other materials because of its high strength to density ratio, resistance to corrosion, and low cost. There is a demand in the SMC industry to be able to characterize SMC processability. This is particularly true for heavy truck body panels, one of the fastest growing applications of SMC. Because of their large size and high strength requirement, the molding forces have a major influence in the molding cycle. Also because of the long flow paths involved, the ability of the paste to carry glass needs to be properly characterized when developing new SMC materials. In this article, we demonstrate the benefits of using spiral flow as a processability tester. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献