全文获取类型
收费全文 | 24887篇 |
免费 | 311篇 |
国内免费 | 539篇 |
专业分类
安全科学 | 698篇 |
废物处理 | 1131篇 |
环保管理 | 3503篇 |
综合类 | 3906篇 |
基础理论 | 6821篇 |
环境理论 | 9篇 |
污染及防治 | 6047篇 |
评价与监测 | 1556篇 |
社会与环境 | 1929篇 |
灾害及防治 | 137篇 |
出版年
2023年 | 110篇 |
2022年 | 222篇 |
2021年 | 203篇 |
2020年 | 211篇 |
2019年 | 182篇 |
2018年 | 873篇 |
2017年 | 804篇 |
2016年 | 866篇 |
2015年 | 454篇 |
2014年 | 528篇 |
2013年 | 1633篇 |
2012年 | 870篇 |
2011年 | 1687篇 |
2010年 | 1149篇 |
2009年 | 1293篇 |
2008年 | 1501篇 |
2007年 | 1743篇 |
2006年 | 821篇 |
2005年 | 770篇 |
2004年 | 756篇 |
2003年 | 752篇 |
2002年 | 748篇 |
2001年 | 860篇 |
2000年 | 648篇 |
1999年 | 378篇 |
1998年 | 260篇 |
1997年 | 267篇 |
1996年 | 250篇 |
1995年 | 299篇 |
1994年 | 243篇 |
1993年 | 242篇 |
1992年 | 202篇 |
1991年 | 210篇 |
1990年 | 203篇 |
1989年 | 209篇 |
1988年 | 171篇 |
1987年 | 149篇 |
1986年 | 171篇 |
1985年 | 155篇 |
1984年 | 214篇 |
1983年 | 170篇 |
1982年 | 192篇 |
1981年 | 170篇 |
1980年 | 139篇 |
1979年 | 158篇 |
1978年 | 105篇 |
1977年 | 106篇 |
1975年 | 99篇 |
1974年 | 99篇 |
1972年 | 104篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
211.
Gabrielle Ednie Tyreen Kapoor Olga Koppel Morgan L. Piczak Jessica L. Reid Alyssa D. Murdoch Carly N. Cook William J. Sutherland Steven J. Cooke 《Ambio》2023,52(2):411
Foresight science is a systematic approach to generate future predictions for planning and management by drawing upon analytical and predictive tools to understand the past and present, while providing insights about the future. To illustrate the application of foresight science in conservation, we present three case studies: identification of emerging risks to conservation, conservation of at-risk species, and aid in the development of management strategies for multiple stressors. We highlight barriers to mainstreaming foresight science in conservation including knowledge accessibility/organization, communication across diverse stakeholders/decision makers, and organizational capacity. Finally, we investigate opportunities for mainstreaming foresight science including continued advocacy to showcase its application, incorporating emerging technologies (i.e., artificial intelligence) to increase capacity/decrease costs, and increasing education/training in foresight science via specialized courses and curricula for trainees and practicing professionals. We argue that failure to mainstream foresight science will hinder the ability to achieve future conservation objectives in the Anthropocene.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-022-01786-0. 相似文献
212.
根据DPSIR模型构建了城市土地资源中生态环境承载力的指标体系,该体系的创新之处在于通过结构化的指标设计将生态环境与人口、经济、社会发展和管理等其他要素纳入统一分析框架,充分考察了各要素之间的密切关联。在实证分析方面,以北京市为例,对其2011—2014年土地资源中生态环境承载力的相关指标变动趋势情况进行分析。结果表明:人口增长与经济增长两大驱动力指标持续上升,对土地资源带来的压力持续存在且逐年增大;城市建设用地的压力不断增大,居住用地造成的压力最为显著;从反应指标和状态指标看,北京市在努力加强城市绿化和生态保护工作,但影响指标目前尚无显著改善,大气污染和水资源短缺等情况仍不容乐观。最后,针对如何评价和提升城市土地资源中生态环境的承载力提出了政策建议。 相似文献
213.
某城市污水处理厂二沉池出水拟采用强化混凝技术进行深度处理后用作邻近发电厂的冷却用水。为了指导生产运行,采用正交试验对强化混凝技术的主要影响因素进行了研究。结果表明:影响因素的主次顺序为助凝剂投加量>搅拌转速>接触污泥浓度>絮凝阶段的pH。强化混凝技术处理该二沉池出水的最佳运行工况:PAM浓度为0.3 mg/L,接触污泥浓度为2.5 g/L,搅拌转速为80 r/min,pH为6.0。在最佳运行工况下,浊度由10.0 NTU降至0.5 NTU以下,TP浓度由1.5 mg/L左右降至1.0 mg/L以下,最低可达0.2 mg/L,优于GB/T 19923—2005《城市污水再生利用 工业用水水质》的相关要求。 相似文献
214.
新化矿区煤矸石中微量元素赋存形态及浸出特征 总被引:1,自引:0,他引:1
利用BCR连续提取法和浸泡实验,对贵州省新化煤矿区不同风化程度的煤矸石中微量元素As、Cd、V、Zn、Co、Cr、Cu、Ni、Pb的赋存形态及浸出浓度进行研究。赋存形态研究结果表明:在煤矸石中As和Cd元素主要以酸溶态、可还原态和可氧化态形式赋存,而其他微量元素V、Zn、Co、Cr、Cu、Ni、Pb主要以残渣态形式赋存;除了V元素的赋存形态含量百分比不受煤矸石风化程度影响外,其它微量元素的赋存形态的含量百分比均会受到煤矸石风化程度的影响。煤矸石的浸出实验表明:浸泡时间是影响煤矸石中微量元素释放的一个重要因素;在浸泡过程中,大部分微量元素在浸泡前期的浸出浓度受煤矸石风化程度的影响,Zn和Cu元素则是在整个浸泡过程的浸出浓度均受到煤矸石风化程度的影响;不同粒径大小的煤矸石在浸泡过程中,除微量元素As和Co的浸出浓度不受煤矸石粒径大小的影响,其他微量元素在浸泡前期和中期的浸出浓度均与煤矸石的粒径大小呈反比。 相似文献
215.
Adsorption of Pb, Cd to Fe, Mn oxides in natural freshwater surface coatings developed in different seasons 总被引:4,自引:0,他引:4
Metal oxides( Fe, Mn oxides) in natural surface coatings(biofilms and associated minerals) are believed to play a significant role n the fate and transport of trace metal in aquatic environments. Seasonal variation of Fe, Mn oxides and organic materials in surface oatings, which were developed periodically on glass slides in Nanhu Lake, Jilin Province, China over the time frame of three seasons,was investigated in order to understand the influence of metal oxides on Pb and Cd adsorption to heterogeneous surface coating materials(biofilm). Pb and Cd adsorption was measured under controlled laboratory conditions( mineral salts solution with defined speciation, ionic trength 0.05 mol/L, 25~C and pH 6.0). The classical Langmuir adsorption isotherm was applied to estimate equilibrium coefficients of Pb nd Cd adsorption to the surface coatings. In general, components in the surface coatings varied greatly with seasons altering and btained higher concentrations in summer while the content of iron oxides always exceeded that of manganese oxides. Correlation nalyses between the maximum adsorption of Pb and Cd and components in the surface coatings developed periodically indicated that Pb hase association with Mn oxides and Cd phase association with Fe oxides as well as Mn oxides were statistically significant. Effect of Mn xides on Cd adsorption was confirmed in view of its higher content in the surface coatings. The importance of ferromanganese oxides for b and Cd adsorption to the natural surface coatings developed in different seasons was evidenced. 相似文献
216.
217.
218.
J. Sun Y. P. Li X. W. Zhuang S.W. Jin G. H. Huang R. F. Feng 《Mitigation and Adaptation Strategies for Global Change》2018,23(4):553-578
In this study, an integrated simulation-based allocation modeling system (ISAMS) is developed for identifying water resources management strategies in response to climate change. The ISAMS incorporates global climate models (GCMs), a semi-distributed land use-based runoff process (SLURP) model, and a multistage interval-stochastic programming (MISP) approach within a general framework. The ISAMS can not only handle uncertainties expressed as probability distributions and interval values but also reveal climate change impacts on water resources allocation under different projections of GCMs. The ISAMS is then applied to the Kaidu-kongque watershed with cold arid characteristics in the Tarim River Basin (the largest inland watershed basin in China) for demonstrating its efficiency. Results reveal that different climate change models corresponding to various projections (e.g., precipitation and temperature) would lead to changed water resources allocation patterns. Variations in water availability and demand due to uncertainties could result in different water allocation targets and shortages. A variety of decision alternatives about water allocations adaptive to climate change are generated under combinations of different global climate models and ecological water release plans. These findings indicate that understanding the uncertainties in water resources system, building adaptive methods for generating sustainable water allocation patterns, and taking actions for mitigating water shortage problems are key adaptation strategies responding to climate change. 相似文献
219.
采用高效菌提高普通活性污泥系统抗2,4-DCP负荷冲击能力 总被引:4,自引:3,他引:4
研究了用于处理生活污水的普通活性污泥反应器(CAS)受到2,4-二氯酚(2,4-DCP)间歇性负荷冲击时,投加高效菌的生物强化系统和对照系统对污染物的响应及系统稳定性,并考察了长期运行过程中强化系统对目标污染物去除能力的变化.结果表明,投加5%和15% 2,4-DCP复合高效菌的强化CAS系统,其对目标污染物的降解能力及抗负荷冲击能力得到显著提高.当系统受到间歇性2,4-DCP负荷冲击[110.37~171.60 mg/(L·d)]时,对于单次投菌后前30日内发生的间歇性负荷冲击,强化系统有效保持了对目标污染物的强化效果;在无2,4-DCP存在的情况下连续运行70d,当系统再次受到2,4-DCP负荷冲击时,强化系统的强化效果与前几次相比已明显下降,不能够快速有效去除污染物并维持系统稳定,因此有必要再次投加高效菌. 相似文献
220.
Fluctuations of bird abundances in the Midwest region of the United States have been attributed to such factors as landscape change, habitat fragmentation, depredation, and supplemental feeding. However, no attempt has been made to estimate the collective role of landowner activities that may influence birds across a landscape. To investigate how landowners might influence birds when the majority (> 90%) of land is privately owned, we surveyed all 1694 private domestic landowners living on three breeding bird survey routes (120 km) that represent a continuum of rural-to-urban landscapes in Southeastern Michigan from October through December 2000. Our survey was designed to investigate (1) the proportion of landowners involved in bird feeding, providing bird houses, planting or maintaining vegetation for birds, gardening, landscaping, applying fertilizer, and applying pesticides or herbicides; (2) whether differences existed between urban, suburban, and rural landowner activities; and (3) whether landowners that carried out a given activity were sociodemographically different from those who did not. Of the 968 respondents (58.5% response rate), 912 (94%) carried out at least one of the activities on their land and the average landowner carried out 3.7 activities. A total of 65.6% fed birds, 45.7% provided bird houses, 54.6% planted or maintained vegetation for birds, 72.7% gardened, 72.3% landscaped, 49.3% applied fertilizer, and 25.2% applied pesticides or herbicides. Significant differences existed between the landscapes, with rural landowners having more bird houses and applying pesticides or herbicides in greater frequency. Similarly, urban landowners had a greater density of bird feeders and houses, but planted or maintained vegetation in the lowest frequency. Participation in activities varied by demographic factors, such as age, gender, and occupation. Scaling each activity to all landowners, including nonrespondents, across all landscapes indicates that between 14% and 82% of landowners may be engaged in a particular activity, with application of pesticides or herbicides having the least potential involvement (13.9%–55.4%) and gardening having the greatest potential involvement (40.1%–81.6%). Taken collectively, our results indicate that landowners are both intentionally and unintentionally engaged in a wide range of activities that are likely to influence bird populations. 相似文献