全文获取类型
收费全文 | 7778篇 |
免费 | 1395篇 |
国内免费 | 1267篇 |
专业分类
电工技术 | 358篇 |
综合类 | 777篇 |
化学工业 | 925篇 |
金属工艺 | 69篇 |
机械仪表 | 271篇 |
建筑科学 | 337篇 |
矿业工程 | 115篇 |
能源动力 | 133篇 |
轻工业 | 3612篇 |
水利工程 | 58篇 |
石油天然气 | 82篇 |
武器工业 | 62篇 |
无线电 | 898篇 |
一般工业技术 | 915篇 |
冶金工业 | 176篇 |
原子能技术 | 136篇 |
自动化技术 | 1516篇 |
出版年
2024年 | 58篇 |
2023年 | 166篇 |
2022年 | 202篇 |
2021年 | 260篇 |
2020年 | 264篇 |
2019年 | 258篇 |
2018年 | 199篇 |
2017年 | 277篇 |
2016年 | 294篇 |
2015年 | 342篇 |
2014年 | 532篇 |
2013年 | 539篇 |
2012年 | 722篇 |
2011年 | 742篇 |
2010年 | 554篇 |
2009年 | 574篇 |
2008年 | 455篇 |
2007年 | 625篇 |
2006年 | 546篇 |
2005年 | 459篇 |
2004年 | 411篇 |
2003年 | 403篇 |
2002年 | 315篇 |
2001年 | 263篇 |
2000年 | 214篇 |
1999年 | 152篇 |
1998年 | 105篇 |
1997年 | 93篇 |
1996年 | 81篇 |
1995年 | 68篇 |
1994年 | 47篇 |
1993年 | 38篇 |
1992年 | 30篇 |
1991年 | 13篇 |
1990年 | 17篇 |
1989年 | 13篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 7篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1968年 | 4篇 |
1961年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
21.
提出了基于曲线进化的运动目标检测算法。对于运动目标检测问题定义了新颖的能量模型,并给出了相应的曲线进化方程。结合水平集算法,所提出的曲线进化模型能够自动的适应拓扑变化,检测出多个运动目标区域及轮廓。从计算物理学领域引入基于偏微分方程的水平集窄带算法,在构造窄带时无需显示的知道曲线的位置,并能够快速的实现。 相似文献
22.
This article theoretically investigates the drying of uncoated paper with gas-fired infrared (IR) emitters installed within the drying section of a given commercial paper machine. Specifically, it presents the ideal location of two opposing IR emitters within the drying section. The ideal location of the two opposing IR emitters corresponds to the highest machine speed with specified average moisture content of paper sheet at the end of the drying section. This article also presents the average evaporation rate, temperature, and moisture content of the paper sheet as it travels through the drying section with the two opposing IR emitters operating at the optimum location. In addition, the temperature and moisture profiles in the sheet thickness direction, before and after the IR emitters, are provided. This article is not concerned with the potential effects of drying with IR emitters on paper sheet properties and machine runnability issues. 相似文献
23.
A series of long-chain quaternary ammonium halogen esters (UKK-chemicals), quaternary dimethyl tallow epoxypropyl ammonium
halogens (EPK1), quaternary ditallow methyl epoxypropyl ammonium halogens (EPK2), and EPK2 oligomers (EPK2P) were synthesized.
At acidic, neutral, or slightly basic conditions, EPK1-, EPK2-, EPK2P-, and UKK-chemicals operate as cationic chemicals. They
can be used, for example, as stock sizings, surface sizings, or fixatives. Stock sizing, surface sizing, and fixative experiments
indicate that EPK1-, EPK2-, EPK2P-, and UKK-chemicals function at least as well as or better than the corresponding synthetic
chemicals used in papermaking. 相似文献
24.
Generation enhances item memory but may not enhance other aspects of memory. In 12 experiments, the author investigated the effect of generation on context memory, motivated in part by the hypothesis that generation produces a trade-off in encoding item and contextual information. Participants generated some study words (e.g., hot-___) and read others (e.g., hot-cold). Generation consistently enhanced item memory but did not enhance context memory. More specifically, generation disrupted context memory for the color of the target word but did not affect context memory for location, background color, and cue-word color. The specificity of the negative generation effect in context memory argues against a general item-context trade-off. A processing account of generation meets greater success. In addition, the results provide no evidence that generation enhances recollection of contextual details. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
25.
26.
着色型珠光颜料涂布纸的研制 总被引:1,自引:1,他引:0
本文论述了着色型珠光颜料涂布纸的研制工作,并对影响珠光涂料制备的几个因素进行探讨.优化结果表明,瓷土0~30%,珠光颜料70%~100%,胶粘剂25%~30%,固含量23%~25%,涂布量10~15g/m2时,其纸面呈现强烈的珠光光泽,适用于胶印. 相似文献
27.
L.J. Webb 《Water research》1985,19(8):969-974
Wastewaters from the manufacture of pulp and paper have given rise to problems of excessive microbial growth in rivers over a number of years. This paper is the first in a series of four articles describing research undertaken by PIRA at four U.K. paper/board mills (one integrated with pulp production) over the period 1978–1980. This first paper briefly reviews the published literature on sewage fungus growth from pulp and paper mill discharges up to 1978, but mainly describes previously unpublished work undertaken by PIRA over the period 1965–1975. This introductory paper thus provides a state-of-the-art review of methods to control sewage fungus growth from pulp and paper mill effluents prior to commencement of the research described in the following three articles. 相似文献
28.
29.
30.