全文获取类型
收费全文 | 1583篇 |
免费 | 74篇 |
国内免费 | 40篇 |
专业分类
电工技术 | 16篇 |
综合类 | 78篇 |
化学工业 | 46篇 |
金属工艺 | 21篇 |
机械仪表 | 71篇 |
建筑科学 | 442篇 |
矿业工程 | 57篇 |
能源动力 | 54篇 |
轻工业 | 33篇 |
水利工程 | 32篇 |
石油天然气 | 43篇 |
武器工业 | 10篇 |
无线电 | 44篇 |
一般工业技术 | 440篇 |
冶金工业 | 20篇 |
自动化技术 | 290篇 |
出版年
2023年 | 16篇 |
2022年 | 29篇 |
2021年 | 36篇 |
2020年 | 55篇 |
2019年 | 55篇 |
2018年 | 41篇 |
2017年 | 36篇 |
2016年 | 73篇 |
2015年 | 67篇 |
2014年 | 111篇 |
2013年 | 118篇 |
2012年 | 121篇 |
2011年 | 105篇 |
2010年 | 78篇 |
2009年 | 97篇 |
2008年 | 96篇 |
2007年 | 101篇 |
2006年 | 92篇 |
2005年 | 84篇 |
2004年 | 66篇 |
2003年 | 50篇 |
2002年 | 38篇 |
2001年 | 17篇 |
2000年 | 19篇 |
1999年 | 20篇 |
1998年 | 12篇 |
1997年 | 14篇 |
1996年 | 10篇 |
1995年 | 2篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 5篇 |
排序方式: 共有1697条查询结果,搜索用时 15 毫秒
1.
ObjectiveTraffic collisions yield a substantial rate of morbidity and injury among child-pedestrians. We explored the formation of an innovative hazard perception training intervention – Child-pedestrians Anticipate and Act Hazard Perception Training (CA2HPT). Training was based upon enhancing participants’ ability to anticipate potential hazards by exposing them to an array of traffic scenes viewed from different angles.MethodTwenty-four 7–9-year-olds have participated. Trainees underwent a 40-min intervention of observing typical residential traffic scenarios in a simulated dome projection environment while engaging in a hazard detection task. Trainees were encouraged to note differences between the scenarios presented to them from separate angles (a pedestrian's point-of-view and a higher perspective angle). Next, trainees and control group members were required to perform crossing decision tasks.ResultsTrainees were found to be more aware of potential hazards related to restricted field of view relative to control.ConclusionsChild pedestrians are responsive to training and actively detecting materialized hazards may enrich child-pedestrians’ ability to cross roads. 相似文献
2.
Drunk drivers are a menace to themselves and to other road users, as drunk driving significantly increases the risk of involvement in road accidents and the probability of severe or fatal injuries. Although injuries and fatalities related to road accidents have decreased in recent decades, the prevalence of drunk driving among drivers killed in road accidents has remained stable, at around 25% or more during the past 10 years. Understanding drunk driving, and in particular, recidivism, is essential for designing effective countermeasures, and accordingly, the present study aims at identifying the differences between non-drunk drivers, drunk driving non-recidivists and drunk driving recidivists with respect to their demographic and socio-economic characteristics, road accident involvement and other traffic and non-traffic-related law violations. This study is based on register-data from Statistics Denmark and includes information from 2008 to 2012 for the entire population, aged 18 or older, of Denmark. The results from univariate and multivariate statistical analyses reveal a five year prevalence of 17% for drunk driving recidivism, and a significant relation between recidivism and the drunk drivers’ gender, age, income, education, receipt of an early retirement pension, household type, and residential area. Moreover, recidivists are found to have a higher involvement in alcohol-related road accidents, as well as other traffic and, in particular, non-traffic-related offences. These findings indicate that drunk driving recidivism is more likely to occur among persons who are in situations of socio-economic disadvantage and marginalisation. Thus, to increase their effectiveness, preventive measures aiming to reduce drunk driving should also address issues related to the general life situations of the drunk driving recidivists that contribute to an increased risk of drunk driving recidivism. 相似文献
3.
Simulating the psychological experience of human vision,a road extraction model based on the format tower is proposed to extract the road in the high resolution remote sensing image from the perspective of morphology.Firstly,based on the spectral and texture information,the suspected road targets are extracted by using segmentation technology.Then these targets are classified according to their reliability and extract the road targets for each category.Finally,three types of identified road information are verified and merged,and the continuous smooth road extraction results are obtained.Experiments on real high resolution images show that the results are consistent with the visual perception of the human eye,and the overall classification accuracy is higher,indicating that the algorithm is effective and feasible and has good use value. 相似文献
4.
The 2011 AASHTO Roadside Design Guide (RDG) contains perhaps the most widely used procedure for choosing an appropriate length of need (LON) for roadside barriers. However, this procedure has several limitations. The procedure uses a highly simplified model of vehicle departure, and the procedure does not allow designers to specify an explicit level of protection. A new procedure for choosing LON that addresses these limitations is presented in this paper. This new procedure is based on recent, real-world road departure trajectories and uses this departure data in a more realistic way. The new procedure also allows LON to be specified for a precisely known level of protection – a level which can be based on number of crashes, injury outcomes or even estimated crash cost – while still remaining straightforward and quick to use like the 2011 RDG procedure. 相似文献
5.
The persistent overrepresentation of young drivers in road crashes is universally recognised. A multitude of factors influencing their behaviour and safety have been identified through methods including crash analyses, simulated and naturalistic driving studies, and self-report measures. Across the globe numerous, diverse, countermeasures have been implemented; the design of the vast majority of these has been informed by a driver-centric approach. An alternative approach gaining popularity in transport safety is the systems approach which considers not only the characteristics of the individual, but also the decisions and actions of other actors within the road transport system, along with the interactions amongst them. This paper argues that for substantial improvements to be made in young driver road safety, what has been learnt from driver-centric research needs to be integrated into a systems approach, thus providing a holistic appraisal of the young driver road safety problem. Only then will more effective opportunities and avenues for intervention be realised. 相似文献
6.
Shunzo Kawajiri Takayuki Kawaguchi Yasuharu Watanabe Hiroshi Hayakawa Yasunori Miyamori Dai Nakamura Satoshi Yamashita 《Soils and Foundations》2019,59(3):764-782
For one week from August 17 to 23, 2016, three consecutive typhoons made landfall in Hokkaido for the first time on record. These typhoons and the front they stimulated brought record-breaking torrential rain over the eastern part of Hokkaido. To investigate the damage to grounds and rivers resulting from this rainfall, the Japan Society of Civil Engineers (JSCE) and the Japanese Geotechnical Society (JGS) formed a disaster research group to conduct an investigation. This report provides the results of the investigation into damage to the grounds of areas along the Tokoro River of the Okhotsk region, Hokkaido, that suffered from this tremendous and diverse disaster. Specifically, the report describes the situation of the levees which were broken and eroded by the overflowing water, the shape of the levee bodies, the levee body soil properties examined by observation of the sections, as well as the occurrence of sand boiling and air blows. The washout of road embankments as well as damage to road bridge mounting fills and abutment backfills were also investigated. The investigation has demonstrated the need to clarify the resistance of the abutment backfills and levee bodies to flowing water as well as the geotechnical predominant factors in order to clarify the mechanisms behind erosion and washout, the need to review new measures that allow for the scale of sand boiling and resultant changes in levee body stability, and the fact that the existing embankments were able to temporarily suppress the flooding water which had spilled over from the river. Furthermore, although it has been identified that the findings of a study on an embankment washout associated with a tsunami can be applied to measures taken against the overflowing water, it has also been found necessary to clarify the predominant geotechnical factors using model tests and to use a more sophisticated analytical approach to establish a geotechnical stability review as soon as possible in order to prevent the levees and embankments from being eroded and washed out due to overflowing water. 相似文献
7.
8.
S.Q. WuS.S. Law 《Engineering Structures》2011,33(2):591-601
The vehicular axle load on top of a bridge deck is estimated in this paper including the effect of the road surface roughness which is modeled as a Gaussian random process represented by the Karhunen-Loève expansion. The bridge is modeled as a simply supported planar Euler-Bernoulli beam and the vehicle is modeled by a four degrees-of-freedom mass-spring system. A stochastic force identification algorithm is proposed in which the statistics of the moving interaction forces can be accurately identified from a set of samples of the random responses of the bridge deck. Numerical simulations are conducted in which the Gaussian assumption for the road surface roughness, the response statistics calculation and the stochastic force identification technique for the proposed bridge-vehicle interaction model are verified. Both the effect of the number of samples used and the effect of different road surface profiles on the accuracy of the proposed stochastic force identification algorithm are investigated. Results show that the Gaussian assumption for the road surface roughness is correct and the proposed algorithm is accurate and effective. 相似文献
9.
随着中国古代城市规划模式由"坊市制"转向更适合于商品经济发展的"坊巷制",宁波老城街道网密度经历了从疏到密的转变;而近现代由于交通方式的变革、土地所有制的变化和建筑生产方式的转变,宁波老城街道网密度又经历了从密返疏的转变.这一从疏到密、从密返疏的演变过程,不仅反映了宁波"城与市"相结合的城市特色,还从一个侧面反映出了中国传统城市格局的演变过程. 相似文献
10.
压力注浆从根本上治理公路工程中的矿井采空塌陷区,本文对该方法的设计、施工及技术要求等若干问题进行探讨。 相似文献