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   511篇
  免费   42篇
  国内免费   21篇
电工技术   77篇
综合类   19篇
化学工业   35篇
金属工艺   7篇
机械仪表   18篇
建筑科学   20篇
矿业工程   2篇
能源动力   11篇
轻工业   15篇
水利工程   22篇
石油天然气   9篇
武器工业   3篇
无线电   6篇
一般工业技术   161篇
冶金工业   113篇
原子能技术   3篇
自动化技术   53篇
  2024年   3篇
  2023年   9篇
  2022年   16篇
  2021年   21篇
  2020年   13篇
  2019年   13篇
  2018年   7篇
  2017年   11篇
  2016年   30篇
  2015年   22篇
  2014年   36篇
  2013年   39篇
  2012年   24篇
  2011年   50篇
  2010年   31篇
  2009年   31篇
  2008年   26篇
  2007年   20篇
  2006年   30篇
  2005年   31篇
  2004年   35篇
  2003年   22篇
  2002年   15篇
  2001年   10篇
  2000年   4篇
  1999年   1篇
  1998年   2篇
  1997年   4篇
  1996年   1篇
  1994年   2篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1982年   1篇
  1980年   1篇
  1967年   1篇
  1964年   1篇
  1962年   1篇
  1956年   1篇
  1955年   1篇
排序方式: 共有574条查询结果,搜索用时 420 毫秒
11.
There is a high potential of severe injury outcomes in traffic crashes on rural interstate highways due to the significant amount of high speed traffic on these corridors. Hierarchical Bayesian models are capable of incorporating between-crash variance and within-crash correlations into traffic crash data analysis and are increasingly utilized in traffic crash severity analysis. This paper applies a hierarchical Bayesian logistic model to examine the significant factors at crash and vehicle/driver levels and their heterogeneous impacts on driver injury severity in rural interstate highway crashes. Analysis results indicate that the majority of the total variance is induced by the between-crash variance, showing the appropriateness of the utilized hierarchical modeling approach. Three crash-level variables and six vehicle/driver-level variables are found significant in predicting driver injury severities: road curve, maximum vehicle damage in a crash, number of vehicles in a crash, wet road surface, vehicle type, driver age, driver gender, driver seatbelt use and driver alcohol or drug involvement. Among these variables, road curve, functional and disabled vehicle damage in crash, single-vehicle crashes, female drivers, senior drivers, motorcycles and driver alcohol or drug involvement tend to increase the odds of drivers being incapably injured or killed in rural interstate crashes, while wet road surface, male drivers and driver seatbelt use are more likely to decrease the probability of severe driver injuries. The developed methodology and estimation results provide insightful understanding of the internal mechanism of rural interstate crashes and beneficial references for developing effective countermeasures for rural interstate crash prevention.  相似文献   
12.
Risk management is becoming increasingly important for railway companies in order to safeguard their passengers and employees while improving safety and reducing maintenance costs. However, in many circumstances, the application of probabilistic risk analysis tools may not give satisfactory results because the risk data are incomplete or there is a high level of uncertainty involved in the risk data. This article presents the development of a risk management system for railway risk analysis using fuzzy reasoning approach and fuzzy analytical hierarchy decision making process. In the system, fuzzy reasoning approach (FRA) is employed to estimate the risk level of each hazardous event in terms of failure frequency, consequence severity and consequence probability. This allows imprecision or approximate information in the risk analysis process. Fuzzy analytical hierarchy process (fuzzy-AHP) technique is then incorporated into the risk model to use its advantage in determining the relative importance of the risk contributions so that the risk assessment can be progressed from hazardous event level to hazard group level and finally to railway system level. This risk assessment system can evaluate both qualitative and quantitative risk data and information associated with a railway system effectively and efficiently, which will provide railway risk analysts, managers and engineers with a method and tool to improve their safety management of railway systems and set safety standards. A case study on risk assessment of shunting at Hammersmith depot is used to illustrate the application of the proposed risk assessment system.  相似文献   
13.
通过分析石家庄西部山区4个代表监测站的历年降水资料,利用《旱情等级标准》中农业旱情指标与等级,12.22009年春季石家庄西部山区的旱情为例,分析了旱灾主要成因,并提出抗旱减灾对策。  相似文献   
14.
Few studies have examined the relationship between life events, suicide attempts, and personality disorders (PDs), in spite of the strong associations between PDs and suicidal behavior, and the poor coping strategies often exhibited by these individuals. The authors examined whether participants with PDs who attempted suicide during the first 3 years of a prospective, longitudinal study were more likely to experience specific life events in the month during and preceding the suicide attempt. Of 489 participants with PDs, 61 attempted suicide during the 3-year, follow-up interval. Results indicated that negative life events, particularly those pertaining to love-marriage or crime-legal matters, were significant predictors of suicide attempts, even after controlling for baseline diagnoses of borderline PD, major depressive disorders, substance use disorders, and a history of childhood sexual abuse. Therefore, certain types of negative life events are unique risk factors for imminent suicide attempts among individuals with PDs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
15.
This study examined the hypothesis that psychotic, borderline, and neurotic personality organizations (POs) present a progressive differentiation between self and object representations and an increasing integration of their bad and good aspects. Fifty patients participated in the study. Measures included scales of self and object representations (S. J. Blatt, S. A. Bers, & C. E. Schaffer, 1993; S. J. Blatt, H. Wiseman, E. Prince-Gibson, & C. Gatt, 1991), as well as the Personality Organization Diagnostic Form (L. Diguer & L. Normandin, 1997) and estimations of psychiatric severity. Results showed that PO groups differed in terms of the integration of the object and its valence. It was also observed that although object and self representations were closely intertwined, the latter showed more discrimination between POs than the former. Psychiatric severity was shown to correlate more with object representations than self representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
16.
Recent research points toward the viability of conceptualizing alcohol problems as arrayed along a continuum. Nevertheless, modern statistical techniques designed to scale multiple problems along a continuum (latent trait modeling; LTM) have rarely been applied to alcohol problems. This study applies LTM methods to data on 110 problems reported during in-person interviews of 1,348 middle-aged men (mean age=43) from the general population. The results revealed a continuum of severity linking the 110 problems, ranging from heavy and abusive drinking, through tolerance and withdrawal, to serious complications of alcoholism. These results indicate that alcohol problems can be arrayed along a dimension of severity and emphasize the relevance of LTM to informing the conceptualization and assessment of alcohol problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
17.
This study was designed to examine the impacts of employees’ cost–benefit analysis, deterrence considerations, and top management support and beliefs on information systems security policy compliance. Surveys of Canadian professionals’ perceptions were carried out. A research model was proposed and tested. The results confirmed that top management support and beliefs, sanction severity, and cost–benefit analysis significantly influenced employees’ information systems security policy compliance. The implications of the study findings are discussed, and conclusions are drawn.  相似文献   
18.
While the number of fatalities on Danish roads has decreased in the last 40 years, research has not investigated the contribution of legislation changes, enforcement measures, technological enhancements, infrastructural improvements and human factors to this reduction. In the context of a Danish car market with remarkably high registration tax that causes potential buyers to hold longer onto old cars, the relationship between technological enhancements of vehicles and severity of crashes requires particular attention.  相似文献   
19.
《Ergonomics》2012,55(11):1353-1375
A prospective epidemiologic study was conducted in two units (140 beds and 57 nursing assistants) of a nursing home to demonstrate the efficacy of an ergonomic intervention strategy to reduce back stress to nursing personnel. The total programme involved the following: determining patient handling tasks perceived to be most stressful by the nursing assistants (NAs); performing an ergonomic evaluation of these tasks; and conducting a laboratory study to select patient transferring devices perceived to produce less physical stress than existing manual patient-handling methods. The intervention phase included training NAs in the use of these devices, modifying toilets and shower rooms, and applying techniques to patient care. Immediately after completing the intervention programme, a post-intervention analysis (which lasted eight months in unit 1 and four months in unit 2) was performed.

A biomechanical evaluation of the physical demands required to perform stressful patient-handling tasks showed that the mean compressive force on the L5/S1 disc, the mean hand force required to make a transfer, and the strength requirements (expressed as percentage female population capable) were 1964?N, 122?N, and 83% after intervention as compared to 4751?N, 312?N, and 41% before intervention. Subjectively, the mean rating of perceived exertion was less than ‘very light’ after intervention as compared to between ‘somewhat hard’ and ‘hard’ before intervention. Overall, the mean acceptability rates for the walking belt and the mechanical hoist were 81% and 87% for patient transfers. The incidence rate for back injuries prior to the intervention, 83 per 200 000 work-hours, decreased to 47 per 200 000 work-hours after the intervention. There were no injuries resulting in lost or restricted work days during the last four months of the post-intervention. It is concluded that an appropriate ergonomic intervention programme offers great promise in reducing physical stress and risk of low-back pain to nursing personnel. However, large-scale studies in different nursing homes are needed to confirm the above findings.  相似文献   
20.
《Ergonomics》2012,55(10):1591-1601
Overexertion injuries have been a major concern to occupational safety and health professionals for quite some time. Over the years, these injuries have continued to increase despite ergonomic interventions to control their frequency of occurrence. It has been speculated that this increase may be due primarily to enhanced awareness and better record-keeping. Many occupational safety and health professionals also presume that overexertion injuries and occupational illnesses are confined to heavy manufacturing industries. This paper reports occupational injury and illness data from a large telecommunication industry, collected over a 7-year period. Three observations were made from the statistical summary: (1) better record keeping may be a reason behind the reported increase in injuries; workday losses decline as a result of improved ergonomic and occupational health interventions; (2) serious injuries are not just limited to heavy manufacturing industries; and (3) reduction in workday losses may not translate in injury cost savings.  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