全文获取类型
收费全文 | 5503篇 |
免费 | 165篇 |
国内免费 | 10篇 |
学科分类
工业技术 | 5678篇 |
出版年
2021年 | 61篇 |
2020年 | 58篇 |
2019年 | 59篇 |
2018年 | 70篇 |
2017年 | 61篇 |
2016年 | 78篇 |
2015年 | 82篇 |
2014年 | 85篇 |
2013年 | 348篇 |
2012年 | 203篇 |
2011年 | 232篇 |
2010年 | 166篇 |
2009年 | 178篇 |
2008年 | 224篇 |
2007年 | 226篇 |
2006年 | 192篇 |
2005年 | 188篇 |
2004年 | 167篇 |
2003年 | 153篇 |
2002年 | 163篇 |
2001年 | 90篇 |
2000年 | 86篇 |
1999年 | 96篇 |
1998年 | 59篇 |
1997年 | 69篇 |
1996年 | 89篇 |
1995年 | 73篇 |
1994年 | 66篇 |
1993年 | 80篇 |
1992年 | 75篇 |
1991年 | 54篇 |
1990年 | 68篇 |
1989年 | 80篇 |
1988年 | 66篇 |
1987年 | 85篇 |
1986年 | 80篇 |
1985年 | 101篇 |
1984年 | 109篇 |
1983年 | 81篇 |
1982年 | 74篇 |
1981年 | 85篇 |
1980年 | 62篇 |
1979年 | 96篇 |
1978年 | 68篇 |
1977年 | 76篇 |
1976年 | 56篇 |
1975年 | 65篇 |
1974年 | 57篇 |
1973年 | 75篇 |
1972年 | 53篇 |
排序方式: 共有5678条查询结果,搜索用时 15 毫秒
41.
Edward Kirby 《Information Systems Management》2013,30(2):85-88
Along with the proliferation of personal computers in companies comes an increased need for security policies and programs. Recent experiences among MIS managers have shown that no degree of security can be considered too great —and it is the company's responsibility to see that these measures are taken. 相似文献
42.
In winter, a common problem is to determine the route that a snowplow should take in order to minimize the distance traveled. We propose a variant of this arc routing problem that is motivated by the fact that deadhead travel over streets that have already been plowed is significantly faster than the time it takes to plow the street. This problem differs from most arc routing problems because the cost of traversing a street changes depending on the order of the streets on a route. We develop a method that generates near-optimal solutions to instances as large as 200 nodes. 相似文献
43.
44.
In this paper, we describe a simplified version of the Advanced Encryption Standard algorithm. This version can be used in the classroom for explaining the Advanced Encryption Standard. After presentation of the simplified version, it is easier for students to understand the real version. This simplified version has the advantage that examples can be worked by hand. We also describe attacks on this version using both linear and differential cryptanalysis. These too can be used in the classroom as a way of explaining those kinds of attacks. 相似文献
45.
J. Edward Jackson 《技术计量学》2013,55(1):197-199
A short-cut rule has been devised for dicotomous data and ill-conditioned quantitative data to test for a one-sided difference between two groups. The rule is defined in terms of a critical count (CC) and a critical difference (CD). For a CC of 4, 8, or 12 the .05 rule is CD equal to 4, 5, or 6, respectively, and the .Ol rule is CD equal to 5, 6, or 7, respectively. 相似文献
46.
47.
48.
Dr. Vladimir O. Talibov Dr. Edoardo Fabini Edward A. FitzGerald Dr. Daniele Tedesco Daniela Cederfeldt Martin J. Talu Moira M. Rachman Filip Mihalic Dr. Elisabetta Manoni Dr. Marina Naldi Dr. Paola Sanese Dr. Giovanna Forte Dr. Martina Lepore Signorile Prof. Xavier Barril Dr. Cristiano Simone Prof. Manuela Bartolini Dr. Doreen Dobritzsch Dr. Alberto Del Rio Prof. U. Helena Danielson 《Chembiochem : a European journal of chemical biology》2021,22(9):1597-1608
SMYD3 is a multifunctional epigenetic enzyme with lysine methyltransferase activity and various interaction partners. It is implicated in the pathophysiology of cancers but with an unclear mechanism. To discover tool compounds for clarifying its biochemistry and potential as a therapeutic target, a set of drug-like compounds was screened in a biosensor-based competition assay. Diperodon was identified as an allosteric ligand; its R and S enantiomers were isolated, and their affinities to SMYD3 were determined (KD=42 and 84 μM, respectively). Co-crystallization revealed that both enantiomers bind to a previously unidentified allosteric site in the C-terminal protein binding domain, consistent with its weak inhibitory effect. No competition between diperodon and HSP90 (a known SMYD3 interaction partner) was observed although SMYD3–HSP90 binding was confirmed (KD=13 μM). Diperodon clearly represents a novel starting point for the design of tool compounds interacting with a druggable allosteric site, suitable for the exploration of noncatalytic SMYD3 functions and therapeutics with new mechanisms of action. 相似文献
49.
50.