首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   629篇
  免费   55篇
  国内免费   1篇
电工技术   6篇
综合类   3篇
化学工业   126篇
金属工艺   13篇
机械仪表   17篇
建筑科学   18篇
能源动力   17篇
轻工业   119篇
水利工程   4篇
石油天然气   1篇
无线电   48篇
一般工业技术   96篇
冶金工业   37篇
原子能技术   2篇
自动化技术   178篇
  2023年   9篇
  2022年   6篇
  2021年   24篇
  2020年   22篇
  2019年   19篇
  2018年   28篇
  2017年   36篇
  2016年   37篇
  2015年   40篇
  2014年   37篇
  2013年   67篇
  2012年   43篇
  2011年   39篇
  2010年   42篇
  2009年   31篇
  2008年   26篇
  2007年   19篇
  2006年   20篇
  2005年   14篇
  2004年   12篇
  2003年   11篇
  2002年   10篇
  2001年   5篇
  2000年   2篇
  1999年   3篇
  1998年   11篇
  1997年   9篇
  1996年   7篇
  1995年   9篇
  1994年   5篇
  1993年   3篇
  1992年   6篇
  1991年   3篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   5篇
  1986年   3篇
  1984年   1篇
  1983年   4篇
  1982年   1篇
  1981年   4篇
  1980年   1篇
  1978年   1篇
  1976年   4篇
  1975年   1篇
  1973年   1篇
排序方式: 共有685条查询结果,搜索用时 15 毫秒
1.
Micha Zeiger 《电子设计技术》2005,12(4):62-62,64-67
设计一种新的系统底板涉及到很多准则,其中包括各种专用功能以及构成任何电信或数据系统一部分的通用模块.这些通用模块,如机械设计、EMI完整性、底板、电源和机架管理,是所有设计共有的.它们对设计的标新立异没有贡献,而且从研发角度来看,可以看作是额外开销.另一方面,与系统有关的特性则是设备专有的,也是实现方法所独有的,并会使系统厂商引入新颖而独特的功能,使其产品不同于竞争对手的产品.  相似文献   
2.
Social dominance orientation (SDO) has been proposed as an important variable in the explanation of prejudice. We distinguish between three conceptualizations of SDO: SDO as a personality trait (personality model), SDO as a moderator of the effects of situational variables (Person X Situation model), and SDO as a mediator of the effect of social position on prejudice (group socialization model [GSM]). Four studies (N = 1,657) looking at the relations between social positions, SDO, and prejudice in a natural setting and in a laboratory setting provide strong support for the GSM. In contrast to previous correlational findings, there is evidence of a cause (dominant social position), an effect (prejudice increases), and a mediator (SDO). These results suggest new perspectives on the integration of individual and contextual determinants of prejudice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
3.
Currently, the sterility of heat‐processed food and pharmaceuticals is assessed in terms of an F0 value, based on the equivalence of the heat treatment to an isothermal process at a reference temperature. This F0 value, however, has a meaning if, and only if, the inactivation kinetics of the targeted spores (or cells) follow a first‐order relationship and the temperature dependence of the D value, the reciprocal of the rate constant, is log‐linear. There is growing evidence that these conditions are not satisfied by many spores, including those of Clostridium botulinum and vegetative cells. Consequently, a replacement for the F0 value is proposed in the form of a momentary equivalent time at the reference temperature based on the actual survival pattern of the spores, which need not be log‐linear. This equivalent time can be calculated together with the theoretical survival ratio in real time, thus enabling an operator to monitor the lethality of ongoing industrial heat processes. The concept is demonstrated with published survival data of C. botulinum, for which the Weibullian and log‐logistic models served as primary and secondary models, respectively. The safety factor according to the proposed method is in the number of added minutes of processing, beyond the theoretical time needed to reduce the survival ratio of the targeted spores or cells to a level that would produce practical (or commercial) sterility. Copyright © 2006 Society of Chemical Industry  相似文献   
4.
It is well known that biological motion conveys a wealth of socially meaningful information. From even a brief exposure, biological motion cues enable the recognition of familiar people, and the inference of attributes such as gender, age, mental state, actions and intentions. In this paper we show that from the output of a video-based 3D human tracking algorithm we can infer physical attributes (e.g., gender and weight) and aspects of mental state (e.g., happiness or sadness). In particular, with 3D articulated tracking we avoid the need for view-based models, specific camera viewpoints, and constrained domains. The task is useful for man–machine communication, and it provides a natural benchmark for evaluating the performance of 3D pose tracking methods (vs. conventional Euclidean joint error metrics). We show results on a large corpus of motion capture data and on the output of a simple 3D pose tracker applied to videos of people walking.  相似文献   
5.
We report the characterization of amphiphilic aminoglycoside conjugates containing luminophores with aggregation-induced emission properties as transfection reagents. These inherently luminescent transfection vectors are capable of binding plasmid DNA through electrostatic interactions; this binding results in an emission “on” signal due to restriction of intramolecular motion of the luminophore core. The luminescent cationic amphiphiles effectively transferred plasmid DNA into mammalian cells (HeLa, HEK 293T), as proven by expression of a red fluorescent protein marker. The morphologies of the aggregates were investigated by microscopy as well as ζ-potential and dynamic light-scattering measurements. The transfection efficiencies using luminescent cationic amphiphiles were similar to that of the gold-standard transfection reagent Lipofectamine® 2000.  相似文献   
6.
7.
8.
An infinite tree is called thin if it contains only countably many infinite branches. Thin trees can be seen as intermediate structures between infinite words and infinite trees. In this work we investigate properties of regular languages of thin trees. Our main tool is an algebra suitable for thin trees. Using this framework we characterize various classes of regular languages: commutative, open in the standard topology, and definable in weak MSO logic among all trees. We also show that in various meanings thin trees are not as rich as all infinite trees. In particular we observe a collapse of the parity index to the level (1, 3) and a collapse of the topological complexity to co-analytic sets. Moreover, a gap property is shown: a regular language of thin trees is either weak MSO-definable among all trees or co-analytic-complete.  相似文献   
9.
It is shown that Theorem 3 in the article mentioned in the title is not true and some modification is suggested to eliminate the mistake.  相似文献   
10.
The article presents a new concept of combining the three dimensions (3D) of a person's manipulation space. The data concern information about the reach of the arms and biomechanical data about limiting the load of a disabled person sitting in a wheelchair. Measurement data were acquired empirically, on original measuring station. The data included, respectively, arms' reach (static and dynamic) or, alternatively, measurements of limiting forces. The obtained data were processed into virtual 3D surfaces of arms' reach and forces. These surfaces provide the required graphic model of anthropotechnical and biomechanical data. Developed model was utilized to perform a virtual analysis of the accessibility of a disabled person to technical means: in a market sale space and in the ergonomic analysis into the space of a personal car. The presented method of 3D graphic modeling of anthropometrical and biomechanical data can be universally applied in ergonomic designing of work stations not only for disabled persons. © 2011 Wiley Periodicals, Inc.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号