全文获取类型
收费全文 | 649篇 |
免费 | 63篇 |
国内免费 | 183篇 |
专业分类
安全科学 | 80篇 |
废物处理 | 9篇 |
环保管理 | 137篇 |
综合类 | 387篇 |
基础理论 | 90篇 |
环境理论 | 5篇 |
污染及防治 | 67篇 |
评价与监测 | 38篇 |
社会与环境 | 60篇 |
灾害及防治 | 22篇 |
出版年
2024年 | 2篇 |
2023年 | 16篇 |
2022年 | 19篇 |
2021年 | 43篇 |
2020年 | 32篇 |
2019年 | 25篇 |
2018年 | 18篇 |
2017年 | 42篇 |
2016年 | 39篇 |
2015年 | 29篇 |
2014年 | 43篇 |
2013年 | 57篇 |
2012年 | 52篇 |
2011年 | 72篇 |
2010年 | 45篇 |
2009年 | 46篇 |
2008年 | 40篇 |
2007年 | 64篇 |
2006年 | 26篇 |
2005年 | 30篇 |
2004年 | 15篇 |
2003年 | 24篇 |
2002年 | 25篇 |
2001年 | 8篇 |
2000年 | 15篇 |
1999年 | 15篇 |
1998年 | 11篇 |
1997年 | 6篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有895条查询结果,搜索用时 31 毫秒
761.
三峡库区的文物保护 总被引:1,自引:0,他引:1
王儒述 《长江流域资源与环境》2002,11(6):549-553
三峡工程规模宏大,举世瞩目,具有防洪、发电、航运等综合效益,是开发治理长江的骨干工程,三峡库区位于长江上游河优的下段,受回水影响的水库淹没区和移民安置涉及的20个县市称库区,总面积约5.5万km^2,三峡库区已发现853处大型文物古迹,水库蓄水后大部分文物古迹将不受影响,但少部分将全部或部分受淹,中国政府一贯重视文物保护工作,三峡工程开工后,已拔出专门经费,组织人力物力,进一步加强文物古迹调查,考古勘探,加速古文化遗址的发掘抢救,切实保护三峡库区文物。 相似文献
762.
介绍了一种新型真空再生的有机胺脱硫技术以及其应用于江铜贵溪冶炼厂硫酸尾气净化的中试运行情况。通过工业性试验验证了该技术的可行性,确定了最佳工艺条件,并测试了脱硫系统的稳定性。结果表明:脱硫剂循环量为9 m3/h、再生塔操作真空度为(35±5)kPa、再生蒸汽压力为0.3~0.35 MPa、蒸汽流量为1.0~1.2 t/h条件下,再生效率大于90%,脱硫效率大于99%,净化气中ρ(SO_2)低于10 mg/m~3。该技术克服了传统有机胺脱硫技术存在的有机胺消耗大、蒸汽耗量大、设备腐蚀严重等问题,具有脱硫效率高、稳定性高、再生蒸汽消耗低、有机胺损耗量低、运行成本低、无二次污染等优点,完全适应于冶金制酸尾气中SO_2的脱除,具有较好的环境效益和经济效益。 相似文献
763.
Anna Carlsson Linda Pipkorn Anders Kullgren Mats Svensson 《Traffic injury prevention》2017,18(4):398-405
Objective: Whiplash-associated disorder (WAD), commonly denoted whiplash injury, is a worldwide problem. These injuries occur at relatively low changes of velocity (typically <25 km/h) in impacts from all directions. Rear impacts, however, are the most common in the injury statistics. Females have a 1.5–3 times higher risk of whiplash injury than males.?Improved seat design is the prevailing means of increasing the protection of whiplash injury for occupants in rear impacts. Since 1997, more advanced whiplash protection systems have been introduced on the market, the Saab Active Head Restraint (SAHR) being one of the most prominent. The SAHR—which is height adjustable—is mounted to a pressure plate in the seatback by means of a spring-resisted link mechanism.?Nevertheless, studies have shown that seats equipped with reactive head restraints (such as the SAHR) have a very high injury-reducing effect for males (~60–70%) but very low or no reduction effect for females. One influencing factor could be the position of the head restraint relative to the head, because a number of studies have reported that adjustable head restraints often are incorrectly positioned by drivers.?The aim was to investigate how female and male Saab drivers adjust the seat in the car they drive the most.Methods: The seated positions of drivers in stationary conditions have been investigated in a total of 76 volunteers (34 females, 42 males) who participated in the study. Inclusion criteria incorporated driving a Saab 9–3 on a regularly basis.Results: The majority of the volunteers (89%) adjusted the head restraint to any of the 3 uppermost positions and as many as 59% in the top position.?The average vertical distance between the top of the head and the top of the head restraint (offset) increase linearly with increasing statures, from an average of ?26 mm (head below the head restraint) for small females to an average of 82 mm (head above the head restraint) for large males. On average, the offset was 23 mm for females, which is within a satisfactory range and in accordance with recommendations; the corresponding value for males was 72 mm.?The backset tended to be shorter among female volunteers (on average 27 mm) compared to the male volunteers (on average 44 mm). Moreover, the backset tended to increase with increasing statures.Conclusions: Incorrect adjustment of the head restraint cannot explain the large differences found between the sexes in the effectiveness of the SAHR system. 相似文献
764.
蒌蒿(Artemisia selengensis)对土壤中镉的胁迫反应及修复潜力研究 总被引:1,自引:0,他引:1
以洞庭湖湿地新发现的Cd高富集植物——蒌蒿(Artemisia selengensis)为试验材料,采用盆栽方式,系统研究了蒌蒿在生长期内对Cd的性状反应及富集特征.结果表明,大于40mg.kg-1的Cd胁迫对蒌蒿叶片伤害明显,且导致生物量下降,但植株在100mg.kg-1胁迫下可完成生活史,对Cd有较强的耐受能力;土壤中有效态Cd的含量仅占土壤全Cd含量的15.3%~37.1%;相同胁迫浓度下,各生长阶段的植株体内Cd含量差别不大,但由于生物量的原因,幼苗期对Cd的提取量显著小于其他时期,其中40~60mg.kg-1的Cd处理可使蒌蒿地上部分Cd含量达492~588mg.kg-1(成株期),且植株对该浓度范围的Cd污染去除效果最好;蒌蒿可作为对湿地土壤Cd污染较理想的修复植物加以研究和利用. 相似文献
765.
为研究不同注气压力与注气温度对CO2置换驱替煤层CH4的影响规律,利用Materials Studio分子动力学模拟软件,通过煤体在2元组分混合气体间的竞争吸附量、竞争吸附热及能量分布等变化规律,从微观研究煤吸附CH4与CO2之间的机理,并利用物理实验平台,选用3种高变质程度煤进行注CO2置换驱替CH4实验。结果表明:同一种变质程度煤,随着注气压力或注气温度的增大,置换率呈增长趋势、驱替比呈下降趋势、CO2突破时间变短;相同注气压力与注气温度时煤的变质程度越高,置换效率越大、驱替比越小、CO2突破时间越长。并且注气压力对于CO2置换驱替CH4的效果要优于注气温度。 相似文献
766.
Introduction: Modern approaches to Occupational Health and Safety have acknowledged the important contribution that continuous improvements to working conditions can make to the motivation of employees, their subsequent performance, and therefore to the competitiveness of the company. Despite this fact, organizational change initiatives represent a path less traveled by employees. Specialized literature has drawn on the fact that employees’ satisfaction presents both the foundation and catalyst for effective implementation of improvements to working conditions. Method: This paper conceptualizes the alignment of employees through measurement of job satisfaction and uses the Bayesian Network to assess the influence of human factors, particularly the cognitive, emotional, and behavioral aspects. Toward this aim, the Bayesian Network is evaluated through a cross-validation process, and a sensitivity analysis is then conducted for each influential dimension: emotional, cognitive, and behavioral. Results: The results reveal that these three dimensions are interrelated and have a direct influence on job satisfaction and employees’ alignment during the organization change. Further, they suggest that the best strategy for enhanced alignment and smooth conduct of organizational changes is simultaneous enhancement of the three dimensions. Practical applications: This study shows the influence of emotional, cognitive, and behavioral dimensions on job satisfaction and employees’ alignment during the organizational change. Furthermore, it elaborates the way to develop efficient and effective strategies for a successful change implementation and sustained alignment. 相似文献
767.
IntroductionFreeway accidents are a leading cause of death in China, which also triggers substantial economic loss and an emotional burden to society. However, the internal mechanism of how microscopic kinetic parameters of vehicles influenced by road characteristics determine the occurrence of different types of accidents has not been explicitly studied. This research aimed to explore the “link role” of tire microscopic kinetic parameters in road characteristic variables and traffic accidents to aid in facilitating the traffic design and management, and thus to prevent traffic accident. Method: A mountain freeway in Zhejiang Province, China was used as the research object and the data used in this paper were obtained through a real-time vehicle experiment. Multiple estimation models, including the standard ordered logit (SOL) model, fixed parameters logit (FPL) model, and random parameters logit (RPL) model were established. Results: The findings show that road characteristics will affect the longitudinal kinetic characteristics of the vehicle and, consequently, map the level of risk of rear-end accidents. Driving compensation effects were also identified in this paper (i.e., the drivers tend to be more cautious in complicated driving circumstances). Another finding relating to the mountain freeway is that different tunnel characteristics (e.g., tunnel entrance and tunnel exit) have different effects on different types of traffic accidents. Practical Applications: The framework proposed in this article can provide new insight for researchers to enlarge the research subjects of both explanatory and outcome variables in accident analysis. Future research could be implemented to consider more driving conditions. 相似文献
768.
Plant polyphenols are involved in important ecosystem processes and may affect nutrient cycling. Previous investigations have demonstrated detrimental effects of suboptimal sample treatment on the quantity of extractable plant polyphenols. We compared leaf polyphenol concentrations of 20 tree species from East China in two sample sets collected under different conditions: (a) according to established protocols and stored more than three years, (b) under conditions optimised for leaf polyphenols. We investigated the variance brought about by suboptimal sample handling as compared to the variance caused by the taxonomic range of species. Family-affiliation explained the largest proportion of variance, whereas sample handling had only minor effects. Reducing the taxonomic range increased the impact of differences in sample handling. Additionally, we showed that the concentrations of leaf polyphenols were phylogenetically more conserved than other leaf traits. Non-metric-multi-dimensional scaling revealed similar ordination patterns for leaf polyphenol concentrations in both sample sets with both ordinations being closely correlated. Finally, we computed separate ordinations including an extended set of leaf traits and found that both analyses led to similar ecological conclusions. Consequently, in studies comprising a wide taxonomic range, the adverse effects of suboptimal sample handling may be overridden by the variation brought about by phylogeny. 相似文献
769.
E. M. Roe 《国际发展与全球生态学杂志》2013,20(2):1-14
SUMMARY What is sustainable development? Why is at an issue? Ideally, what needs to be done? and Practically, what can be done? are answered here by relying on the cultural theory of Mary Douglas and her colleagues, more especially Aaron Wildavsky and Michael Thompson, both of whom have used the model to address sustainable development. The implications of cultural theory for sustainable development are substantial. The article is divided into five sections. The first describes the current controversy over sustainable development. The second sets out the cultural theory model, and the third applies that model to reformulate our understanding of sustainable development. The fourth draws out the implications of a reformulated sustainable development, while the conclusion uses those implications to answer the four questions that started the article. 相似文献
770.