全文获取类型
收费全文 | 34930篇 |
免费 | 457篇 |
国内免费 | 716篇 |
专业分类
安全科学 | 1134篇 |
废物处理 | 1605篇 |
环保管理 | 4694篇 |
综合类 | 5433篇 |
基础理论 | 8986篇 |
环境理论 | 11篇 |
污染及防治 | 9332篇 |
评价与监测 | 2423篇 |
社会与环境 | 2220篇 |
灾害及防治 | 265篇 |
出版年
2023年 | 164篇 |
2022年 | 342篇 |
2021年 | 368篇 |
2020年 | 313篇 |
2019年 | 308篇 |
2018年 | 575篇 |
2017年 | 552篇 |
2016年 | 865篇 |
2015年 | 637篇 |
2014年 | 965篇 |
2013年 | 2941篇 |
2012年 | 1222篇 |
2011年 | 1639篇 |
2010年 | 1381篇 |
2009年 | 1427篇 |
2008年 | 1577篇 |
2007年 | 1706篇 |
2006年 | 1489篇 |
2005年 | 1239篇 |
2004年 | 1198篇 |
2003年 | 1165篇 |
2002年 | 1101篇 |
2001年 | 1409篇 |
2000年 | 1039篇 |
1999年 | 668篇 |
1998年 | 454篇 |
1997年 | 449篇 |
1996年 | 491篇 |
1995年 | 495篇 |
1994年 | 433篇 |
1993年 | 411篇 |
1992年 | 379篇 |
1991年 | 366篇 |
1990年 | 372篇 |
1989年 | 365篇 |
1988年 | 322篇 |
1987年 | 271篇 |
1986年 | 255篇 |
1985年 | 259篇 |
1984年 | 338篇 |
1983年 | 282篇 |
1982年 | 341篇 |
1981年 | 268篇 |
1980年 | 229篇 |
1979年 | 279篇 |
1978年 | 200篇 |
1977年 | 188篇 |
1976年 | 167篇 |
1975年 | 163篇 |
1974年 | 164篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
11.
12.
Baek Kitae Alessi Daniel S. Man Yu Bon Kwon Eilhann E. 《Environmental geochemistry and health》2021,43(9):3261-3262
Environmental Geochemistry and Health - 相似文献
13.
Mehmet B. Ercan Iman Maghami Benjamin D. Bowes Mohamed M. Morsy Jonathan L. Goodall 《Journal of the American Water Resources Association》2020,56(1):53-67
Climate change poses water resource challenges for many already water stressed watersheds throughout the world. One such watershed is the Upper Neuse Watershed in North Carolina, which serves as a water source for the large and growing Research Triangle Park region. The aim of this study was to quantify possible changes in the watershed’s water balance due to climate change. To do this, we used the Soil and Water Assessment Tool (SWAT) model forced with different climate scenarios for baseline, mid‐century, and end‐century time periods using five different downscaled General Circulation Models. Before running these scenarios, the SWAT model was calibrated and validated using daily streamflow records within the watershed. The study results suggest that, even under a mitigation scenario, precipitation will increase by 7.7% from the baseline to mid‐century time period and by 9.8% between the baseline and end‐century time period. Over the same periods, evapotranspiration (ET) would decrease by 5.5 and 7.6%, water yield would increase by 25.1% and 33.2%, and soil water would increase by 1.4% and 1.9%. Perhaps most importantly, the model results show, under a high emission scenario, large seasonal differences with ET estimated to decrease by up to 42% and water yield to increase by up to 157% in late summer and fall. Planning for the wetter predicted future and corresponding seasonal changes will be critical for mitigating the impacts of climate change on water resources. 相似文献
14.
Chengyuan Gong Yi Yu Kaiqiang Wang Zhengkai Tu 《International Journal of Green Energy》2020,17(10):591-601
ABSTRACT In this study, a three-dimension (3D) computational model was proposed to investigate the flow and heat transfer characteristics of the intake grilles of two different fuel cell vehicles. The models of the intake grilles were constructed according to the actual sizes of two vehicles, namely, Roewe 950 and Toyota Mirai, considering the heat dissipation unit to simplify the heat transfer model of the vehicle. The results showed that relative to Roewe 950, Mirai intake air flow rate was approximately 10% higher, the heat transfer capacity was approximately 7% higher, and the intake grille area was larger. The coolant outlet temperature of Mirai was lower than that of Roewe 950, which was beneficial for the long term and stable operation of a fuel cell. This comparative study provided guidance for the intake grille and radiator design of fuel cell vehicles. The only difference between fuel cell vehicles on the market and conventional vehicles was that in the former, the internal combustion engine was replaced with a fuel cell stack, which had insufficient heat transfer capacity because of the reducing temperature difference. Increasing the intake grille area and the heat exchange capacity of the radiator were the key issues for the development of fuel cell vehicles. In this study, an optimal window opening angle of the radiator fin of 23° provided a maximal heat transfer coefficient. 相似文献
15.
16.
Rebecca Niemiec Megan S. Jones Stacy Lischka Veronica Champine 《Conservation biology》2021,35(4):1073-1085
Research suggests that encouraging motivated residents to reach out to others in their social network is an effective strategy for increasing the scale and speed of conservation action adoption. However, little is known about how to effectively encourage large numbers of residents to reach out to others about conservation causes. We examined the influence of normative and efficacy-based messaging at motivating residents to engage in and to encourage others to participate in native plant gardening in their community. To do so, we conducted a field experiment with messages on mailings and tracked native plant vouchers used. Efficacy messages tended to be more effective than normative messages at increasing residents’ willingness to reach out to others to encourage conservation action, as indicated by a several percentage point increase in native plant voucher use by residents’ friends and neighbors. Messages sometimes had different impacts on residents based on past behaviors and perceptions related to native plant gardening. Among these subgroups, efficacy and combined efficacy and norm messages most effectively encouraged individual and collective actions, as indicated by increased voucher usage. Our findings suggest that interventions that build residents’ efficacy for engaging in a conservation behavior and for reaching out to others may be a promising path forward for outreach. However, given our results were significant at a false discovery rate cutoff of 0.25 but not 0.05, more experimental trials are needed to determine the robustness of these trends. 相似文献
17.
es Ruiz de Arcaute Celeste Ossana Natalia A. Pérez-Iglesias Juan Manuel Soloneski Sonia Larramendy Marcelo L. 《Environmental science and pollution research international》2019,26(20):20485-20498
Environmental Science and Pollution Research - Pesticides might increase the production of reactive oxygen species (ROS). Dicamba (DIC) and 2,4-dichlorophenoxyacetic acid (2,4-D) are auxinic... 相似文献
18.
19.
冻融循环作用下尾矿砂抗剪强度和变形特性研究 总被引:2,自引:0,他引:2
为探究冻融循环后尾矿物理力学特性的变化特征,使用高低温试验箱和应变控制式三轴剪力仪对处于不同初始条件下的尾矿砂进行不排水不固结试验,揭示了尾矿砂的抗剪强度参数、不同围压条件下的变形模量与冻融循环次数、含水率之间的关系。结果表明:相同含水率条件下,随冻融循环次数增加,尾矿砂黏聚力先减小后趋于稳定,内摩擦角先增大后减小,围压100 k Pa和200 k Pa时变形模量逐渐减小,围压300 k Pa时变形模量呈现先减小后缓慢增大的趋势;相同冻融循环次数条件下,随尾矿砂含水率增加,其黏聚力先增加后减小、内摩擦角不断减小;不同围压条件下变形模量在总体上均呈现出不断减小的变化趋势,围压200 k Pa时变形模量总的衰减量最大,100k Pa次之,300 k Pa最小。 相似文献
20.
de Carvalho George Harrison Ferreira de Andrade Milene Aparecida de Araújo Carla Nunes Santos Maria Lucília de Castro Natália Alves Charneau Sébastien Monnerat Rose de Santana Jaime Martins Bastos Izabela Marques Dourado 《Environmental science and pollution research international》2019,26(6):5514-5523
Environmental Science and Pollution Research - Aedes aegypti and Culex quinquefasciatus are vectors of diseases that constitute public health problems. The discovery of products capable of... 相似文献