全文获取类型
收费全文 | 45438篇 |
免费 | 413篇 |
国内免费 | 332篇 |
专业分类
安全科学 | 1223篇 |
废物处理 | 2483篇 |
环保管理 | 5875篇 |
综合类 | 6166篇 |
基础理论 | 12417篇 |
环境理论 | 10篇 |
污染及防治 | 10981篇 |
评价与监测 | 3502篇 |
社会与环境 | 3305篇 |
灾害及防治 | 221篇 |
出版年
2023年 | 182篇 |
2022年 | 388篇 |
2021年 | 394篇 |
2020年 | 243篇 |
2019年 | 302篇 |
2018年 | 1873篇 |
2017年 | 1794篇 |
2016年 | 1955篇 |
2015年 | 750篇 |
2014年 | 1026篇 |
2013年 | 3031篇 |
2012年 | 1646篇 |
2011年 | 2843篇 |
2010年 | 1967篇 |
2009年 | 1915篇 |
2008年 | 2471篇 |
2007年 | 2697篇 |
2006年 | 1523篇 |
2005年 | 1335篇 |
2004年 | 1283篇 |
2003年 | 1310篇 |
2002年 | 1253篇 |
2001年 | 1449篇 |
2000年 | 1004篇 |
1999年 | 633篇 |
1998年 | 479篇 |
1997年 | 479篇 |
1996年 | 495篇 |
1995年 | 579篇 |
1994年 | 483篇 |
1993年 | 425篇 |
1992年 | 459篇 |
1991年 | 447篇 |
1990年 | 429篇 |
1989年 | 422篇 |
1988年 | 370篇 |
1987年 | 299篇 |
1986年 | 293篇 |
1985年 | 319篇 |
1984年 | 348篇 |
1983年 | 322篇 |
1982年 | 332篇 |
1981年 | 281篇 |
1980年 | 215篇 |
1979年 | 235篇 |
1978年 | 196篇 |
1977年 | 176篇 |
1975年 | 179篇 |
1973年 | 212篇 |
1972年 | 175篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
201.
202.
PROBLEM: There is limited information about how parents view teen driving risks and intend to handle these risks during the licensing process, and how they will respond to graduated licensing provisions. METHODS: Parents in Connecticut were interviewed when their teens got their learner's permit. The survey was undertaken when the state did not have a midnight restriction or a passenger restriction. RESULTS: Generally, parents were well aware of teen driving risks, thought parents should be thoroughly involved in the licensing process, and plan to be active participants themselves. DISCUSSION: Parents were concerned about the risk of driving after midnight and already restrict that behavior. However, parents do not seem to see or understand the risks of having even one teen passenger in the vehicle. IMPACT ON INDUSTRY: The views and existing practices of parents need to be taken into account in deciding on the provisions of graduated licensing legislation and how to best ensure acceptance and compliance. 相似文献
203.
Ibrahim Sheikh AK Radin Umar RS Habshah M Kassim H Stevenson M Ahmed H 《Traffic injury prevention》2006,7(2):150-154
OBJECTIVE: In developing countries, motorcycle use has grown in popularity in the past decades. Commensurate with this growth is the increase in death and casualties among motorcyclists in these countries. One of the strategic programs to minimize this problem is to reduce motorcyclists exposure by shifting them into safer modes of transport. This study aims to explore the differences in the characteristics of bus and motorcycle users. It identifies the factors contributing to their choice of transport mode and estimates the probability that motorcyclists might change their travel mode to a safer alternative; namely, bus travel. METHODS: In this article, a survey of 535 motorcycle and bus users was conducted in seven districts of Selangor state, Malaysia. A binary logit model was developed for the two alternative modes, bus and motorcycle. RESULTS: It was found that travel time, travel cost, gender, age, and income level are significant in influencing motorcyclists' mode choice behavior. The probability of motorcycle riders shifting to public transport was also examined based on a scenario of a reduction in bus travel time and travel cost. CONCLUSIONS: Reduction of total travel time for the bus mode emerges as the most important element in a program aimed at attracting motorcyclists towards public transport and away from the motorcycle mode. 相似文献
204.
OBJECTIVE: To determine the characteristics of speeders, defined as drivers of vehicles traveling at least 15 mph above the posted speed limit and relatively faster than surrounding vehicles. METHODS: Vehicle speeds were recorded on 13 roads in Virginia with speed limits ranging from 40 to 55 mph. Speeders were compared with slower drivers, defined as drivers of adjacent vehicles traveling no more than 5 mph above the speed limit. License plates were used to identify vehicle owners; owners were inferred to have been driving if observed gender and estimated age matched those of the registered owner. For these drivers, information on exact driver age and gender, vehicle make and model, and driving record was obtained from the Virginia Department of Motor Vehicles. RESULTS: Five percent of the vehicles observed were traveling at least 15 mph above the limit, and 3% qualified as speeders, as defined in this study. Speeders were younger than drivers in the comparison group, drove newer vehicles, and had more speeding violations and other moving violations on their records. They also had 60% more crashes. DISCUSSION: Speeders are a high-risk group. Their speeding behavior is not likely to be controlled without vigorous, consistent enforcement, including the use of automated technology. 相似文献
205.
206.
Cardiovascular disease has severe consequences for both individual betterment and organizational health. Yet, organization‐based cardiovascular research remains quite limited. This commentary addresses this void by integrating research dating from the famous Hawthorne experiments with current medical science. It then suggests future organizational research on cardiovascular health and recommends use of specific composite cardiovascular measures to advance our understanding of the organizational implications of cardiovascular disease. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
207.
Previous research indicates that the use of impression management is related to supervisor ratings of employee likeability and job performance. It has been argued, though, that employees might also use impression management so that their superiors will see them as ‘good soldiers’ who engage in high levels of organizational citizenship behaviors (OCBs). This study investigates the ways in which three types of impression management—namely, job‐focused, self‐focused, and supervisor‐focused tactics of impression management—influence supervisor ratings of OCB. Using a sample of 122 supervisor‐subordinate dyads, the findings indicate that supervisor‐focused tactics of impression management are positively related to OCB ratings, while job‐focused tactics are negatively related to such evaluations. Additionally, citizenship behaviors are positively related to supervisor liking of the employee and overall ratings of job performance. Finally, the results suggest that OCB ratings mediate the relationship between supervisor‐focused tactics of impression management and supervisor evaluations of employee likeability. Some implications of this study and directions for future research are also addressed. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
208.
Jeffrey H. Kahn Kimberly T. Schneider Theresa M. Jenkins‐Henkelman Laura L. Moyle 《组织行为杂志》2006,27(6):793-807
The authors investigated whether the relationship between the contents of emotional social support and job burnout among high‐school teachers is spurious because of the role of dispositional positive and negative affectivity. A national sample of 339 teachers was surveyed via a web‐based procedure. Hierarchical regression analyses did not support spuriousness; emotional social support was uniquely predictive of three dimensions of burnout controlling for affectivity. As positive emotional social support increased, emotional exhaustion and cynicism decreased, and professional efficacy increased. As negative emotional social support increased, emotional exhaustion and cynicism also increased. Commonality analyses based on the present data and data reported by K. L. Zellars and P. L. Perrewé (2001; Journal of Applied Psychology, 86, 459–467) provided additional support for the unique role of emotional social support on burnout, but these analyses suggest a greater role of affectivity than emotional social support. These findings have implications for research on burnout as well as the prevention of burnout among teachers. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
209.
This study meta‐analyzed the relationships between locus of control (LOC) and a wide range of work outcomes. We categorized these outcomes according to three theoretical perspectives: LOC and well‐being, LOC and motivation, and LOC and behavioral orientation. Hypotheses reflecting these three perspectives were proposed and tested. It was found that internal locus was positively associated with favorable work outcomes, such as positive task and social experiences, and greater job motivation. Our findings are discussed in relation to research on core self‐evaluation and the Big Five personality traits. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
210.
Characteristics of large cooking oil pool fires and their extinguishment by water mist 总被引:1,自引:0,他引:1
Z. Liu D. Carpenter A.K. Kim 《Journal of Loss Prevention in the Process Industries》2006,19(6):516-526
Large cooking oil pool fires, occurring in industrial oil cookers, present a severe hazard to food processing plants due to their size and the large amount of hot oil involved. This paper reports a series of full-scale fire experiments conducted in a large industrial oil cooker mock-up. The characteristics of large cooking oil pool fires and the effect of oil depth and hood position in the oil cooker on fire growth were studied. The use of water mist for extinguishing large oil pool fires and their extinguishing performance under different discharge pressure and with different types of water mist systems were investigated. Experimental results showed that the cooking oil underwent a substantial expansion in volume during heating. The fires developed quickly once the oil auto-ignited. The fire growth rate was affected by the oil depth in the pan and the hood position in the oil cooker. The water mist fire suppression systems effectively extinguished large cooking oil fires and prevented them from re-igniting. Their extinguishing performance was determined by the type of water mist system, discharge pressure and hood position in the oil cooker. 相似文献