首页 | 官方网站   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   1229篇
  免费   285篇
  国内免费   188篇
工业技术   1702篇
  2024年   6篇
  2023年   30篇
  2022年   67篇
  2021年   62篇
  2020年   82篇
  2019年   72篇
  2018年   64篇
  2017年   66篇
  2016年   83篇
  2015年   59篇
  2014年   123篇
  2013年   115篇
  2012年   116篇
  2011年   136篇
  2010年   97篇
  2009年   85篇
  2008年   79篇
  2007年   90篇
  2006年   73篇
  2005年   53篇
  2004年   53篇
  2003年   22篇
  2002年   20篇
  2001年   13篇
  2000年   7篇
  1999年   5篇
  1998年   6篇
  1994年   3篇
  1993年   1篇
  1992年   1篇
  1991年   3篇
  1988年   1篇
  1986年   2篇
  1984年   1篇
  1983年   3篇
  1982年   1篇
  1979年   1篇
  1966年   1篇
排序方式: 共有1702条查询结果,搜索用时 15 毫秒
21.
Modern network systems have much trouble in security vulnerabilities such as buffer overflow, bugs in Microsoft Internet, sensor network routing protocol too simple, security flaws of applications, and operating systems. Moreover, wireless devices such as smart phones, personal digital assistants (PDAs), and sensors have become economically feasible because of technological advances in wireless communication and manufacturing of small and low-cost sensors. There are typologies of vulnerabilities to be exploited in these devices. In order to improve securities, many mechanisms are adopted, including authentication, cryptography, access control, and intrusion detection systems (IDS). In general, intrusion detection techniques can be categorized into two groups: misuse detection and anomaly detection. The misuse detection systems use patterns of weB-known attacks or weak spots of the systems to identify intrusions. The weakness of misuse detection systems is unable to detect any future (unknown) intrusion until corresponding attack signatures are intruded into the signature database. Anomaly detection methods try to determine whether the deviation is from the established normal usage patterns or not. The critical success of anomaly detection relies on the model of normal behaviors.  相似文献   
22.
Continued and frequent use of social network sites (SNS) has been linked to a fear of missing out (FOMO) and online self-promotion in the form of friending and information disclosure. The present paper reports findings from 506 UK based Facebook users (53% male) who responded to an extensive online survey about their SNS behaviours and online vulnerability. Structural equation modelling (SEM) suggests that FOMO mediates the relationship between increased SNS use and decreased self-esteem. Self-promoting SNS behaviours provide more complex mediated associations. Longitudinal support (N = 175) is provided for the notion that decreased self-esteem might motivate a potentially detrimental cycle of FOMO-inspired online SNS use. The research considers the implications of social networking on an individual's online vulnerability.  相似文献   
23.
Ignition and combustion characteristics of a low-vulnerability propellant based on RDX are studied experimentally. Ignition is obtained using a laser diode. Experiments are performed in a cylindrical closed-volume reactor for different initial pressures and initial propellant masses under nitrogen and argon surrounding atmospheres. Ignition delays, maximal overpressures, and propagation rates are obtained for different initial pressures and laser powers. Thermodynamic predictions of overpressures are also compared with experimental ones. Finally, ignition probabilities for different laser powers and gaseous atmospheres are investigated using a revised Langlie method.  相似文献   
24.
Facial affect processing is essential to social development and functioning and is particularly relevant to models of depression. Although cognitive and interpersonal theories have long described different pathways to depression, cognitive-interpersonal and evolutionary social risk models of depression focus on the interrelation of interpersonal experience, cognition, and social behavior. We therefore review the burgeoning depressive facial affect processing literature and examine its potential for integrating disciplines, theories, and research. In particular, we evaluate studies in which information processing or cognitive neuroscience paradigms were used to assess facial affect processing in depressed and depression-susceptible populations. Most studies have assessed and supported cognitive models. This research suggests that depressed and depression-vulnerable groups show abnormal facial affect interpretation, attention, and memory, although findings vary based on depression severity, comorbid anxiety, or length of time faces are viewed. Facial affect processing biases appear to correspond with distinct neural activity patterns and increased depressive emotion and thought. Biases typically emerge in depressed moods but are occasionally found in the absence of such moods. Indirect evidence suggests that childhood neglect might cultivate abnormal facial affect processing, which can impede social functioning in ways consistent with cognitive-interpersonal and interpersonal models. However, reviewed studies provide mixed support for the social risk model prediction that depressive states prompt cognitive hypervigilance to social threat information. We recommend prospective interdisciplinary research examining whether facial affect processing abnormalities promote—or are promoted by—depressogenic attachment experiences, negative thinking, and social dysfunction. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
25.
The current study examined vulnerability to depression during the transition from early to middle adolescence from the perspective of the response styles theory. During an initial assessment, 382 adolescents (ages 11–15 years) completed self-report measures assessing rumination and depressive symptoms as well as a semistructured clinical interview assessing current and past major depressive episodes. Every 3 months for the subsequent 2 years, adolescents completed self-report measures assessing depressive symptoms and negative events. Every 6 months, adolescents completed a semistructured clinical interview assessing the onset of new major depressive episodes. Higher levels of rumination were associated with a greater likelihood of exhibiting a past history of major depressive episodes, a greater likelihood of experiencing the onset of a future major depressive episode, and greater duration of future depressive episodes. Consistent with a vulnerability-stress perspective, rumination moderated the association between the occurrence of negative events and the development of future depressive symptoms and major depressive episodes. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
26.
Attributional style is hypothesized to be a causative factor in depression vulnerability; however, no studies to date have examined whether manipulation of attributional style influences depressed mood. The purpose of this study was to determine whether computer-based cognitive bias modification (CBM) procedures could modify attributional style and influence stress vulnerability. Participants were provided with multiple training trials that were intended to promote the use of either a positive or a negative attributional style. Compared with individuals in the negative attributional style condition, individuals in the positive attributional style condition showed decreased tendency to make self-deficient causal attributions for poor performance on a difficult anagram test. Furthermore, individuals in the positive attributional style condition reported less depressed mood in response to this academic stressor. These results suggest that attributional style is not invariable and can potentially be modified with CBM approaches. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
27.
风险评估是发现薄弱环节的基本方法,不仅需在系统建设之前进行,更要贯彻在信息系统从设计到运行乃至到报废的整个生命周期之中。信息安全风险评估是建立信息安全体系的基础,是信息系统安全工程的一个关键组成部分。分析了国内外信息安全风险评估的现状,包括相关的评估标准体系、评估方法和评估过程,针对中国信息安全发展现状,探讨了目前信息安全风险评估工作中急需解决的问题。  相似文献   
28.
信息系统漏洞挖掘技术体系研究   总被引:2,自引:0,他引:2  
首先讨论漏洞挖掘相关的术语定义,分析漏洞挖掘目标对象特点,研究漏洞挖掘的一般流程,然后利用层次结构模型方法,创造性地提出了5层漏洞挖掘技术体系架构模型,并详细描述基础层、抽象层、挖捌层、分析层和利用层的内容、作用及其相关支撑技术.最后指出漏洞挖掘技术的发展方向是兼顾各层、协同发展.  相似文献   
29.
陈亮  韩豫  毛龙泉  成虎 《江苏建筑》2011,(3):111-114
大型公共建筑是开放复杂系统,其风险由可靠性风险、安全性风险和可持续发展性风险构成.大型公共建筑的风险评估、需要从系统的角度,针对3类风险的不同特性,采用定性与定量结合的方法,进行系统的风险评估.针对可靠性风险侧重系统的可靠程度评估,安全性风险侧重风险源和系统脆弱性评估,可持续发展性风险侧重关联风险事件评估.大型公共建筑...  相似文献   
30.
随着集团公司办公管理转向信息化,如何防止企业机密信息外泄已经成了安全保卫工作的重中之重。有关数据显示,我国每年因网络泄密导致的经济损失达上百亿!各国相关行业法律法规对相关企事业单位的数据防泄密做了严格规定。分析了常见的安全漏洞,提出利用前沿网络技术解决数据泄密问题,指出方便快捷的网络通讯平台和越来越先进的数据获取技术,让数据保护工作更具有挑战性。  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-23

京公网安备 11010802026262号