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   267篇
  免费   8篇
化学工业   72篇
金属工艺   2篇
机械仪表   12篇
建筑科学   3篇
轻工业   1篇
水利工程   2篇
石油天然气   1篇
无线电   25篇
一般工业技术   72篇
冶金工业   17篇
原子能技术   13篇
自动化技术   55篇
  2024年   1篇
  2023年   1篇
  2022年   4篇
  2021年   8篇
  2020年   9篇
  2019年   5篇
  2018年   12篇
  2017年   6篇
  2016年   7篇
  2015年   6篇
  2014年   10篇
  2013年   8篇
  2012年   9篇
  2011年   16篇
  2010年   13篇
  2009年   8篇
  2008年   15篇
  2007年   10篇
  2006年   13篇
  2005年   13篇
  2004年   8篇
  2003年   4篇
  2002年   7篇
  2001年   5篇
  2000年   4篇
  1999年   9篇
  1998年   4篇
  1997年   6篇
  1996年   3篇
  1995年   3篇
  1993年   4篇
  1992年   1篇
  1991年   3篇
  1990年   3篇
  1988年   2篇
  1987年   5篇
  1986年   5篇
  1985年   1篇
  1984年   8篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1979年   2篇
  1978年   1篇
  1977年   2篇
  1976年   2篇
  1975年   1篇
  1972年   1篇
  1971年   2篇
  1967年   1篇
排序方式: 共有275条查询结果,搜索用时 23 毫秒
91.
92.
The current study set to examine whether there are inter-generational and gender-based differences between family members self-assessing their ability to drive under normal conditions and while under the influence of either alcohol or drugs. Participants were 135 young-adults and both their parents, consisting 45 family triads, who received self-assessment questionnaires relating to their driving skills in various road scenarios. Each family triad was randomly assigned to one of three groups: either requested to base the assessments on normal driving conditions, or under the influence of either drugs or alcohol, thus forming a control group, and two experimental groups (alcohol and drugs), respectively.The findings indicate the assessments of both the alcohol and drugs groups were more severe than those of the control group. The alcohol group assessments were less strict than the drug group assessment (non-significantly). Inter-generational differences indicated that the parents’ driving-skills assessments were lower than those of their offspring, corresponding with previous findings (Elkind, 1967, Finn and Bragg, 1986).A significant within-subject interaction has been found between the respondent's gender and familial relations regarding the self-assessment of driving skills: male respondents assessed better driving skills compared to the self estimates of both parents (which did not significantly differ). In contrast, female respondents’ estimates did not differ from their fathers’ and both fathers’ and daughters’ estimates were significantly higher than that of the mothers in each family.  相似文献   
93.
The vehicle impoundment sanction in Israel is applicable to several violations, and authorizes police officers to impound a vehicle for period of 30 days, in addition to license suspension. This study examined the effects of vehicle impoundment on traffic-violations and road accidents in Israel, using both subjective and objective measures. A telephone survey was administered to 378 impounded drivers, examining their knowledge and support of the impoundment penalty, as well as the impoundment's effect on their daily life and subsequent driving behaviors. Survey results indicated most impounded drivers did not recognize the violations to which impoundment applies. Respondents described the impoundment experience as one, which interfered with a variety of daily life aspects, and eventually lead them to the adoption of safer driving behaviors. Additionally, data analysis of police records was performed on 1549 impounded drivers and 1354 controls with matching violations performed prior to the application of the impoundment regulation, comparing accident and traffic-violations involvement in the subsequent year. Results indicated that impoundment failed to yield a significant effect over subsequent accident involvement, compared to previous sanctions. A comparison of subsequent traffic-violations indicated lower rates of violations following impoundment as compared with previous sanctions. Specifically, drivers whose vehicle was impounded were less likely to commit traffic violations in the following year than drivers subjected to other sanctions. The results are explained according to psychological behavioral theories of punishment effectiveness. These findings provide further support for impoundment as a deterrent for several traffic-violations.  相似文献   
94.
The purpose of the study was to compare the reported approaches of truck drivers to those of non-truck drivers toward reckless on-road behaviors. One hundred and sixty-seven adult males, including 70 non-truck drivers, completed the questionnaires voluntarily. The truck drivers were employees of a concrete manufacturing company working at various company plants throughout Israel. Seventy were professional mixer truckers and 27 were tip-truckers. The participants completed the Reckless Driving Self-Report Scale based on Taubman Ben-Ari et al. [Taubman Ben-Ari, O., Florian, V., Mikulincer, M., 1999. The impact of mortality salience on reckless driving: a test of terror management mechanisms. Journal of Personality and Social Psychology 76, 35-45], adapted for truck drivers for this study. It was expected that non-professional, as compared to professional (truck) drivers, would be more permissive regarding reckless driving, since driving risks are less prominent in their daily driving experience. An ANOVA performed on mean reckless-driving scores yielded significant results. The post hoc Schéffe test indicated significantly higher reckless-driving scores for automobile drivers as compared to both mixer-truck driver scores and tip-truck driver scores. In addition, the reckless-driving scores for mixer-truck drivers were significantly higher than the tip-truck driver scores. We discuss various explanations for the findings and consider possible implications for training strategies in organizations as well as for media campaigns focused on mutual safe road use of truck drivers and private vehicle drivers.  相似文献   
95.
We provide a qualitative review of key X-ray spectral diagnostics of astrophysical plasmas. We begin with a brief discussion of the two major types of equilibria, collisional ionization and photoionization, and then consider the behaviour of hydrogen-like, helium-like, iron L-shell and iron K-shell transitions for these separate cases. Where possible, we discuss explicit examples using high-resolution spectra acquired by the grating instruments on the Chandra and XMM-Newton observatories.  相似文献   
96.
We present an algorithm for real-time, robust, vision-based active tracking and pursuit. The algorithm was designed to overcome problems arising from active vision-based pursuit, such as target occlusion. Our method employs two layers to deal with occlusions of different lengths. The first layer is for short- or medium-term occlusions: those where a known method—such as mean shift combined with a Kalman filter—fails. For this layer we designed the hybrid filter for active pursuit (HAP). HAP utilizes a Kalman filter modified to respond to two different modes of action: one in which the target is positively identified and one in which the target identification is uncertain. For long-term occlusions we use the second layer. This layer is a decision algorithm that follows a learning procedure and is based on game theory-related reinforcement (Cesa-Bianchi and Lugosi, Prediction Learning and Games, 2006). The learning process is based on trial and error and is designed to perform adequately with a small number of samples. The algorithm produces a data structure that can be shared among agents or sent to a central control of a multi-agent system. The learning process is designed so that agents perform tasks according to their skills: an efficient agent will pursue targets while an inefficient agent will search for entering targets. These capacities make this system well suited for embedding in a multi-agent control system.  相似文献   
97.
We present a system that tracks an articulated body performing 3D movement with occlusions using a combination of cameras and mirrors. By integrating cameras and mirrors we get a simultaneous coverage of almost every point on the target and avoid occlusions. The suggested setup is much simpler and easier to handle compared to the equivalent, camera-based setup. Our tracking algorithm is model-based, and errors in the model are treated using the bundle adjustment procedure. In order to deal with the problem of feature visibility, each feature is set to be valid or invalid based on the model and on its expected appearance; this ensures that the system always tracks a set of distinguishable features. The proposed algorithm was able to track targets in 3D using the Gauss–Newton method to minimize geometric errors. We tested our setup by tracking the chameleon’s eyes. Tracking the eyes of a chameleon can be considered as the estimation of the 3D pose of an articulated body, where the head of the chameleon is considered as a rigid body, and each of the two eyes has additional two degrees of freedom. The algorithm proposed can be easily expanded to cope with more complex objects.  相似文献   
98.
Neonatal intensive care units (NICUs), like other intensive care units, are intended to provide immediate responses to any change in the patients condition. Patient-monitoring alarms and alarms from other medical equipment are very common in these units, and most alarms have no clinical significance. This study addresses the question of how alarms affect nurses actions by measuring the occurrence of alarms from different causes in a NICU, recording the nurses reactions, and analyzing the relationship between the alarms and the actions. The results show that nurses often do not respond directly to alarms, but, rather, use them as additional sources of information in their ongoing flow of actions. The probabilities for their responding to an alarm depend on the causes of the alarm, its duration, and the characteristics of the patient. These findings support the view that experienced nurses dynamically adjust their activities according to the information they receive from alarm systems and other sources, and that they combine their reactive actions with the periodic performance of routine tasks.  相似文献   
99.
This article presents an attempt to employ a programming approach to mathematical formalization. Six self-instructional units (120 instructional hours) have been developed for the Open University in Israel. This material was tried on three different types of populations: (a) bright high school students (11th–12th grade, A-level mathematics), (b) mathematics teachers with a programming background, and (c) university students studying mathematics, natural sciences and engineering. The results indicated that the programming approach is complementary to high school and university mathematics. The opportunity to explore, the algorithmic approach to mathematical operations and the visualization of mathematical objects and processes facilitates mathematical understanding and insights. It was most beneficial to the majority of the students who perform on a moderate level of abstraction. The course was less advantageous to those who have a very abstract way of perceiving mathematics or to those who are interested in mathematics only on a technical level. However, the vast majority of students gained new ways of understanding mathematical topics such as functions, curves, probability, game theory, recursive functions, envelopes, tiling, curve fitting, etc. They gained, as well, new strategies of using microcomputers to solve and further explore many mathematical problems which they could not solve before.  相似文献   
100.
Carny O  Shalev DE  Gazit E 《Nano letters》2006,6(8):1594-1597
The design and fabrication of complex nanostructures with specific geometry and composition is one of the main challenges of nanotechnology. Here we demonstrate the devise of metal-insulator-metal, trilayered, coaxial nanocables. Such coaxial geometry may give rise to useful and unique electromagnetic properties. We have fabricated these nanostructures using a scaffold of self-assembled peptide nanotubes. Gold nanoparticles were bound to the surface of peptide nanotubes via a common molecular recognition element that was included in various linker peptides. This enabled us to promote site-specific metal reduction and to create the coaxial nanostructure. Using electron microscopy, 1H NMR spectra, and energy-dispersive X-ray analysis, we monitored the different steps within the process, gaining further understanding of its mechanism.  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