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   2845篇
  免费   204篇
  国内免费   2篇
电工技术   14篇
综合类   2篇
化学工业   747篇
金属工艺   14篇
机械仪表   22篇
建筑科学   205篇
矿业工程   8篇
能源动力   51篇
轻工业   381篇
水利工程   43篇
石油天然气   4篇
无线电   172篇
一般工业技术   440篇
冶金工业   573篇
原子能技术   6篇
自动化技术   369篇
  2024年   7篇
  2023年   48篇
  2022年   85篇
  2021年   179篇
  2020年   91篇
  2019年   111篇
  2018年   127篇
  2017年   97篇
  2016年   114篇
  2015年   68篇
  2014年   103篇
  2013年   183篇
  2012年   157篇
  2011年   244篇
  2010年   168篇
  2009年   183篇
  2008年   159篇
  2007年   153篇
  2006年   123篇
  2005年   77篇
  2004年   90篇
  2003年   76篇
  2002年   47篇
  2001年   40篇
  2000年   37篇
  1999年   25篇
  1998年   20篇
  1997年   19篇
  1996年   21篇
  1995年   22篇
  1994年   16篇
  1993年   12篇
  1992年   10篇
  1991年   6篇
  1990年   14篇
  1989年   13篇
  1988年   8篇
  1987年   5篇
  1986年   6篇
  1985年   5篇
  1984年   4篇
  1979年   4篇
  1976年   4篇
  1974年   4篇
  1947年   8篇
  1946年   5篇
  1945年   6篇
  1944年   11篇
  1943年   7篇
  1942年   10篇
排序方式: 共有3051条查询结果,搜索用时 31 毫秒
41.
Cardiac catheterization is one of the critical procedures in patient care. It is pertinent for all process related issues in this department to be handled with due priority. This research is a cross-functional effort with a leading hospital that was in its planning stage to implement an overall process improvement at its cardiac catheterization lab department. It has been determined that significant process delays exist in this department. One of the identified key factors to process improvement was to reduce patient turnaround time. Process mapping was used to study the system and identify potential sources of delays in the system. A set of qualitative recommendations were put forward. These recommendations, include the reduction of wait time of outpatients and inpatients and the reduction of non-value-added times such as transfer time of patients, were evaluated using a discrete event simulation approach. The simulation study shows that the daily operating hours at the catheterization lab could be reduced, aiding to reallocate staff for discharging other duties, as the hospital may require.  相似文献   
42.
This small scale action research study investigated the experiences of learners over two iterations as they completed a patchwork text assignment within the digital medium of a personal learning system (PLS). The aim was to investigate the extent to which using a PLS can facilitate formative and collaborative feedback to assist student learning. A secondary question, linked to the course being a post graduate Certificate for new HE teachers within a geographically dispersed university, was to examine if using a PLS in the programme would influence their interest in using it with their own students in the future. This question is of particular importance for the tutors of this programme, as the university attracts mainly part-time students who are studying at a distance from the university campus. The study was carried out as part of the JISC funded Flourish Project, whose overall aim was to examine the use of a PLS to support the development of academic staff.  相似文献   
43.
This study investigated the short-term effects of daily recovery, that is, impaired psychological detachment from work and various actigraphical indicators of sleep quality, on near-accidents when commuting to work the next morning. Furthermore, the mediating effect of actigraphically assessed sleep quality on the relationship between impaired psychological detachment from work and near-accidents when commuting to work was analysed. Fifty-six full-time employees of a Swiss assurance company participated in the one-week study. Multilevel analyses revealed that impaired detachment was highly related to a decrease in sleep duration. Furthermore, impaired daily recovery processes, such as impaired psychological detachment from work and disturbed sleep quality, were related to commuting near-accidents. Impaired sleep quality mediated the effect of impaired psychological detachment from work on these near-accidents. Our results show that occupational safety interventions should address both impaired psychological detachment from work and sleep quality in order to prevent near accidents when commuting to work.

Practitioner Summary: Commuting accidents occur frequently and have detrimental effects on employees, organisations and society. This study shows that daily lack of recovery, that is, impaired psychological detachment and impaired sleep quality, is related to near-accidents when commuting to work the next morning. Primary prevention of commuting accidents should therefore address daily lack of recovery.  相似文献   

44.
In this paper, a modified generalized function projective synchronization scheme for a class of master–slave chaotic systems subject to dynamic disturbances and input nonlinearities (dead-zone and sector nonlinearities) is investigated. This synchronization system can be seen as a generalization of many existing projective synchronization schemes (namely the function projective synchronization, the modified projective synchronization and so on), in the sense that the master system has a scaling function matrix and the slave system has a scaling factor matrix. To practically achieve this generalized function synchronization, an adaptive fuzzy variable-structure control system is designed. The fuzzy systems are used to appropriately approximate the uncertain nonlinear functions. A Lyapunov approach is employed to prove the boundedness of all signals of the closed-loop control system as well as the exponential convergence of the synchronization errors to an adjustable region. Simulations results are presented to illustrate the effectiveness of the proposed generalized function PS scheme.  相似文献   
45.
This paper reviews literature on information channel type and disasters, and presents results on hurricane evacuation information gathering. Results show that respondents reported they would use television and radio most frequently for gathering information about hurricane evacuation. Minority respondents reported more preference of the use of community or local government as information sources than white respondents, females gathered information from multiple channels more than males, and younger residents gathered information from multiple channels more than older respondents. Implications include areas for future research in how channel utilization occurs during slow onset hazards in predominantly black communities, how age and gender relate to channel preference, and how channel preferences affect length of time to make decisions and engage in protective actions.  相似文献   
46.
The retina is a tiny layer at the posterior pole of an eye and is made up of tissues sensitive to light, these tissues generate nerve signals that pass through the optic nerve to the brain. A retinal disorder occurs when the retina malfunctions; glaucoma, diabetic retinopathy and pathologic myopia are retinal disorders and principal causes of blindness worldwide. These retinal disorders are often diagnosed and treated by an ophthalmologist. However, to accurately assess a retinal disease, ophthalmologist would need qualitative and quantitative analysis of the disease, it’s early and current statistics, but acquisition of these measurements are not possible through manual techniques, there should be automated computer aided diagnosis (CAD) systems to assist ophthalmologists. In this comprehensive review, an analysis and evaluation has been performed of different computer vision and image processing approaches applied to OCT images for automatic diagnosis of retinal disorders. We also reported disease causes, symptoms and pathologies manifestations within OCT images, which can serve as baseline knowledge for development of an automated CAD system. Hence, this disease specific review offers a good understanding to analyze visual impairments from retinal OCT images which will help researcher to design enhanced therapeutic systems for retinal disorders.  相似文献   
47.
One of the recurring questions in designing dynamic control environments is whether providing more information leads to better operational decisions. The idea of having every piece of information is increasingly tempting (and in safety critical domains often mandatory) but has become a potential obstacle for designers and operators. The present research study examined this challenge of appropriate information design and usability within a railway control setting. A laboratory study was conducted to investigate the presentation of different levels of information (taken from data processing framework, Dadashi et al. in Ergonomics 57(3):387–402, 2014) and the association with, and potential prediction of, the performance of a human operator when completing a cognitively demanding problem-solving scenario within railways. Results indicated that presenting users only with information corresponding to their cognitive task, and in the absence of other, non task-relevant information, improves the performance of their problem-solving/alarm handling. Knowing the key features of interest to various agents (machine or human) and using the data processing framework to guide the optimal level of information required by each of these agents could potentially lead to safer and more usable designs.  相似文献   
48.
With quantum computers being out of reach for now, quantum simulators are alternative devices for efficient and accurate simulation of problems that are challenging to tackle using conventional computers. Quantum simulators are classified into analog and digital, with the possibility of constructing “hybrid” simulators by combining both techniques. Here we focus on analog quantum simulators of open quantum systems and address the limit that they can beat classical computers. In particular, as an example, we discuss simulation of the chlorosome light-harvesting antenna from green sulfur bacteria with over 250 phonon modes coupled to each electronic state. Furthermore, we propose physical setups that can be used to reproduce the quantum dynamics of a standard and multiple-mode Holstein model. The proposed scheme is based on currently available technology of superconducting circuits consist of flux qubits and quantum oscillators.  相似文献   
49.
Map information for drivers is usually presented in an allocentric-topographic form (as with printed maps) or in an egocentric-schematic form (as with road signs). The advent of new variable message boards on UK motorways raises the possibility of presenting road maps to reflect congestion ahead. Should these maps be allocentric-topographic or egocentric-schematic? This was assessed in an eye tracking study, with participants viewing maps of a motorway network in order to identify whether any congestion was relevant to their intended route. The schematic-egocentric maps were responded to most accurately with shorter fixation durations suggesting easier processing. In particular, the driver's entrance and intended exit from the map were attended to more in the allocentric maps. Individual differences in mental rotation ability also seem to contribute to poor performance on allocentric maps. The results favour schematic-egocentric maps for roadside congestion information, but also provide theoretical insights into map-rotation and individual differences. Statement of Relevance: This study informs designers and policy makers about optimum representations of traffic congestion on roadside variable message signs and, furthermore, demonstrates that individual differences contribute to problems with processing certain sign types. Schematic-egocentric representations of a motorway network produced the best results, as noted in behavioural and eye movement measures.  相似文献   
50.
Muller MD  Ryan EJ  Kim CH  Muller SM  Glickman EL 《Ergonomics》2011,54(11):1081-1087
In the cold, Purdue Pegboard (PP) performance declines. The purpose of this study was to determine if this cold-induced impairment is consistent across days (i.e. test-retest reliability) in 5°C. In thermoneutral air (25°C), 14 men were familiarised to the dominant hand (PPa) and bimanual (PPb) PP tasks. They then experienced two 90-min cold exposures (Day 1, Day 2) while wearing ~1 clo. Bare hands were maintained throughout. Performance on both tasks showed high reliability from day to day (intraclass correlations >0.700) in both thermoneutral and cold conditions. However for both tasks, room temperature performance did not predict performance in the cold (intraclass correlations <0.450). When screening applicants for manual labour in the cold, one must consider that room temperature dexterity does not correlate with dexterity in the cold. It is recommended that a 60-min period of cold exposure be employed to assess manual dexterity in these workers. STATEMENT OF RELEVANCE: This study shows that PP performance in room temperature does not predict performance in the cold but performance in the cold is consistent from day to day. When screening applicants for manual labour in the cold, it is recommended that dexterity tests be conducted in the same ambient conditions.  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