全文获取类型
收费全文 | 31360篇 |
免费 | 260篇 |
国内免费 | 322篇 |
专业分类
安全科学 | 825篇 |
废物处理 | 1419篇 |
环保管理 | 3629篇 |
综合类 | 5469篇 |
基础理论 | 7892篇 |
环境理论 | 9篇 |
污染及防治 | 8192篇 |
评价与监测 | 2367篇 |
社会与环境 | 1958篇 |
灾害及防治 | 182篇 |
出版年
2022年 | 310篇 |
2021年 | 301篇 |
2020年 | 193篇 |
2019年 | 256篇 |
2018年 | 477篇 |
2017年 | 475篇 |
2016年 | 756篇 |
2015年 | 529篇 |
2014年 | 865篇 |
2013年 | 2480篇 |
2012年 | 1012篇 |
2011年 | 1300篇 |
2010年 | 1133篇 |
2009年 | 1169篇 |
2008年 | 1314篇 |
2007年 | 1390篇 |
2006年 | 1248篇 |
2005年 | 1074篇 |
2004年 | 1032篇 |
2003年 | 1018篇 |
2002年 | 965篇 |
2001年 | 1325篇 |
2000年 | 901篇 |
1999年 | 588篇 |
1998年 | 381篇 |
1997年 | 374篇 |
1996年 | 415篇 |
1995年 | 421篇 |
1994年 | 391篇 |
1993年 | 335篇 |
1992年 | 363篇 |
1991年 | 349篇 |
1990年 | 352篇 |
1989年 | 332篇 |
1988年 | 316篇 |
1987年 | 242篇 |
1986年 | 233篇 |
1985年 | 244篇 |
1984年 | 271篇 |
1983年 | 256篇 |
1982年 | 287篇 |
1981年 | 237篇 |
1980年 | 193篇 |
1979年 | 230篇 |
1978年 | 207篇 |
1977年 | 180篇 |
1976年 | 180篇 |
1975年 | 161篇 |
1974年 | 176篇 |
1972年 | 150篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
INTRODUCTION: Alcohol use, alcohol misuse, and risky driving from adolescence into young adulthood were compared by drinking onset age. METHODS: Surveys were administered in Grades 5/6, 6/7, 7/8, 10, 12, and at approximately age 23. Participants were placed into Drinking Onset groups based on self-reported alcohol use frequency on the adolescent surveys. Driving records were examined in three age periods: under 21, 21-25, and 26+. RESULTS: The earliest drinking initiators reported higher alcohol use and misuse on each survey, and were more likely to have risky driving offenses before age 21 and to have alcohol driving offenses in all three age periods. DISCUSSION: The earliest drinking initiators engaged in risky drinking behavior and risky driving behavior that was consistently higher than those with later drinking initiation, beginning in adolescence and persisting well into young adulthood. 相似文献
182.
183.
TED R. MILLER REBECCA S. SPICER DIANE C. LESTINA DAVID T. LEVY 《Traffic injury prevention》2013,14(1):25-34
This study compares highway crash incidence, injuries, and costs by vehicle type. Annual crash and injury incidence were estimated using Crashworthiness Data System (1988-1991), National Automotive Sampling System (1982-1986), General Estimates System (1992-1993), and Fatal Analysis Reporting System (1993) data. Costs were computed based on restraint use, body region, and threat-to-life severity of the injury. Costs were then allocated between vehicle types using three different methods in order to answer comparative safety questions. Motor vehicle and bicycle crash costs total $389 billion annually; 75% resulting from passenger vehicles. Motorcycles and bicycles have the highest costs per 1000 vehicle and passenger miles; costs per victim are highest for pedestrians, bicyclists, and motorcyclists. Costs per vehicle mile for heavy trucks and passenger cars are comparable but exceed costs for light trucks. Passenger vehicle occupants are safest if a crash occurs. Light truck, other single truck, and bus occupants have the lowest cost per passenger mile, but higher costs than air and rail travelers. Motorcyclists face the greatest risks. Combination trucks may not impose an excess risk to other drivers, but their drivers face large risks. 相似文献
184.
The clinical presentation of cervical and basilar skull fractures following bead impact is often complex, particularly when multiple noncontiguous fractures are present. Based on the results of 22 human cadaver head-neck impact experiments, a biomechanical framework of spinal injury is developed in which these complex cases may be better understood. This includes the significance of head rebound, head and neck decoupling, cervical spine buckling, cervical injury mechanisms, basilar skull fractures, and cervical spine tolerance. These data also demonstrate that compliant pads significantly increase the risk for spinal injury though they also significantly reduce peak head force and the head injury criteria (p < 0.04). On the basis of these observations, we hypothesize that impact injury should be modeled as the dynamic response of two large masses, coupled by a segmented curved beam-column composed of seven small masses with interposed nonlinear viscoelastic flexibility elements. 相似文献
185.
Izabella Krucińska Sławomir Zakrzewski Irena Kowalczyk Jadwiga Wiśniewska-Konecka 《International journal of occupational safety and ergonomics》2013,19(3-4):141-149
Five variants of mixtures of different synthetic fibres at different area ratios were manufactured into needled nonwovens intended to be used as a filtering material for respiratory protection. Two variants were produced according to an earlier patent, and the contents of the other three was completely new. Samples of the nonwovens were tested for sodium chloride particles penetration and for breathing resistance. The results showed that one variant of a nonwoven, designated PP/PPFM, had very valuable filtering properties and that those properties were stable in time. 相似文献
186.
Danuta Roman-Liu Krzysztof Kędzior 《International journal of occupational safety and ergonomics》2013,19(1):109-124
The aim of this study was to verify a theoretical model for upper extremity work space optimization. In order to do that, experimental studies were conducted in which two parameters of the electromyography (EMG) signal were analyzed: AMP (amplitude calculated as Root Mean Square) and SZC (coefficient of the slope of the regression line between time and Zero Crossing values). Values of forces in muscles (parameter MOD) were calculated from theoretical studies. A comparison of experimental (AMP, SZC) and theoretical (MOD) parameters was performed by analyzing the coefficient of correlation between those parameters and differentiation of muscular load according to external load value. Analysis showed that the theoretical and experimental results are in step, which means that the developed model can be used for upper extremity work space optimization. 相似文献
187.
Integrated Estimation of the Effect of Physical Factors on Human Functional State During Mental Work
German A. Suvorov Ralemma F. Afanasieva Nataliya S. Mikhailova Migran A. Babayan Alexander F. Bobrov 《International journal of occupational safety and ergonomics》2013,19(2):149-161
The purpose of this study was to develop a model for an integrated estimation of the functional state of the human organism (FSHO) and an integral estimation of physical factors (PF) for hygienic rating. Tests were performed twice with 3 men in 0.7-clo clothing during 4-hr mental work with 9 combinations of 4 PF: wideband noise (55–83 dB(A)), whole-body vibration (6 Hz, az = 0.2–1.8 ms?2), air temperature (18–30 °C), and illumination (1, 3, 5 lx). Thermoregulatory, cardiovascular, and psychophysiological reactions and temporary threshold of hearing (TTS2) shifts were studied. For the integral estimation of PF influence on FSHO the model F(y1, y2, ... ym) = f(x1, x2, ... xn) was used, relating both FSHO and PF sets. The most important physiological parameters in creating FSHO are defined and the contribution of individual parameters of FSHO and PF is found. 相似文献
188.
Jerzy Słowikowski Maria Konarska 《International journal of occupational safety and ergonomics》2013,19(4):369-377
The study aimed at verifying a hypothesis that supporting a visual signal of regulation deviation with an auditory one could improve the quality of regulation; the operator would have better information on machine operation. A special simulator was applied to follow-up tracking with a manual lever which controlled vertical movements of a cursor on a monitor screen. Simultaneously with visual information on screen, the operator was provided with an auditory deviation signal of pre-determined characteristics. 33 young males underwent the test. It was found that supporting a visual signal with an auditory one resulted in an improvement in the regulation quality by 5-6%, which proved synergy between those signals. The results may be used in designing tele- and servo-mechanisms, especially for remote control machinery, e.g., inspection robots or micromanipulators controlled by operators in a follow-up system. 相似文献
189.
Pranab K. Nag Anjali Nag Priyanka Shah 《International journal of occupational safety and ergonomics》2013,19(4):573-581
Properties of supporting surfaces of a seat have an influence on postural control. Centre of pressure (COP) displacement parameters reflect both the balance controlling process and movements of the centre of a mass of entire body. The subjects of the study were 9 healthy men. A seat cushion was examined with a 2-force platform setup. Force exertion at a seat pan and feet and COP displacement at a seat pan were measured to analyse postural control. Analysis of variance determined the differences in postural control depending on a cushion type among the subjects. Significant differences in COP displacement parameters were in COP trajectory length, medio-lateral COP displacement and COP velocity. The results of the study showed that foam cushion ensures better postural control. 相似文献
190.
S.P.M. Bane J.L. Ziegler P.A. Boettcher S.A. Coronel J.E. Shepherd 《Journal of Loss Prevention in the Process Industries》2013,26(2):290-294
Quantifying the risk of accidental ignition of flammable mixtures is extremely important in industry and aviation safety. The concept of a minimum ignition energy (MIE), obtained using a capacitive spark discharge ignition source, has traditionally formed the basis for determining the hazard posed by fuels. While extensive tabulations of historical MIE data exist, there has been little work done on ignition of realistic industrial and aviation fuels, such as gasoline or kerosene. In the current work, spark ignition tests are performed in a gaseous kerosene–air mixture with a liquid fuel temperature of 60 °C and a fixed spark gap of 3.3 mm. The required ignition energy was examined, and a range of spark energies over which there is a probability of ignition is identified and compared with previous test results in Jet A (aviation kerosene). The kerosene results are also compared with ignition test results obtained in previous work for traditional hydrogen-based surrogate mixtures used in safety testing as well as two hexane–air mixtures. Additionally, the statistical nature of spark ignition is discussed. 相似文献