全文获取类型
收费全文 | 328篇 |
免费 | 19篇 |
国内免费 | 108篇 |
专业分类
安全科学 | 20篇 |
废物处理 | 1篇 |
环保管理 | 39篇 |
综合类 | 216篇 |
基础理论 | 102篇 |
污染及防治 | 19篇 |
评价与监测 | 5篇 |
社会与环境 | 33篇 |
灾害及防治 | 20篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 14篇 |
2019年 | 14篇 |
2018年 | 12篇 |
2017年 | 10篇 |
2016年 | 21篇 |
2015年 | 19篇 |
2014年 | 19篇 |
2013年 | 23篇 |
2012年 | 21篇 |
2011年 | 30篇 |
2010年 | 22篇 |
2009年 | 29篇 |
2008年 | 16篇 |
2007年 | 21篇 |
2006年 | 12篇 |
2005年 | 19篇 |
2004年 | 20篇 |
2003年 | 15篇 |
2002年 | 14篇 |
2001年 | 16篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 14篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1991年 | 5篇 |
1990年 | 1篇 |
排序方式: 共有455条查询结果,搜索用时 15 毫秒
101.
对文山州2002年畜禽养殖业污染现状进行了调查,针对畜禽养殖污染存在的问题,提出了畜禽养殖污染防治的对策措施和建议. 相似文献
102.
103.
中药废水处理工程应用研究 总被引:1,自引:0,他引:1
西安市某制药厂中药废水具有水量水质变化大,可生化性较差的特点.采用电解+水解酸化+ ABR厌氧+接触氧化+絮凝沉淀组合工艺对其进行处理;平均进水p(CODcr)=4 600 mg/L,平均出水p(CODcr)=42 mg/L,CODcr平均去除率为99.1%.实践结果表明,该工艺运行费用低,操作简便,易于维护,处理效果稳定,其出水各项指标均优于《黄河流域(陕西段)污水综合排放标准》(DB 61/224-2011)二级标准. 相似文献
104.
Peter H. Koehn 《国际发展与全球生态学杂志》2013,20(4):380-396
Perpetuation of the South-North divide over climate change threatens to undermine the sustainability of the planet's vulnerable ecosystems. The current focus of international attention is on the USA and the PRC since both countries are in a position to negate or clinch the global warming mitigation efforts of the rest of the world community and because the two governments are primarily responsible for the entrenched global impasse over greenhouse gas (GHG) abatement. This contribution illustrates how transnational non-state actors, specifically Chinese American transmigrants, can make a difference in surmounting the US-China divide over GHG emissions, even in a time of state stalemate. Specific opportunities to shape sustainable development outcomes are explored by reference to energy efficiency, renewable energy, transportation, GHG capture, and public education projects. The discussion shows that, by teaming up with the NGOs, universities, foundations and firms engaged in or contemplating involvement in GHG emission mitigation projects in China, Chinese Americans from many walks of life who can manoeuvre skilfully along the climate change frontier occupy a potentially decisive position in terms of supporting sustainable development. 相似文献
105.
文章选用凡尔赛营养液作为基础培养液,分别加入一种含钛植物生长促进剂和TiCl4溶液,以早熟五号大白菜为试验对象,基础培养液作为对照,考察钛元素对大白菜生长的影响及与其他营养元素之间的关系。结果表明:施加含有相同含钛量的植物生长促进剂与TiCl4溶液的大白菜中单株大白菜鲜重增幅分别为35.4%和23.1%;可溶性糖含量增幅为162.5%及118.8%;大白菜中硝酸盐含量的降低幅度分别为15.2%和13.8%;亚硝酸盐含量的降低幅度分别为36.4%和33.8%。同时,还测量了其他相关指标如株高、叶面积、叶绿素含量等。添加TiCl4的培养液与对照相比,在各项指标中都表现出优势,与添加植物生长促进剂的培养液相比,叶绿素、硝酸盐等指标相差不明显。 相似文献
106.
107.
推进生态文明、建设美丽中国,进而实现中华民族伟大复兴的中国梦,已成为中国共产党及其所领导的中国人民的最大追求和奋斗目标.一直为国民经济主战场服务的中国旅游地理,生态文明建设必然为其教材建设的主体内容之一.该文结合《中国旅游地理》(第四版)创新实际,仅就中国旅游地理推进生态文明建设教学内容体系构建及其构架进行了探索.参9. 相似文献
108.
This research aimed to study the effect of ultra-micro powder Dendrobium officinale on the molecular diversity of intestinal bacteria in mice with spleen-deficiency constipation, in order to provide scientific basis for ultra-micro D. officinale therapy. The mice with spleen-deficiency constipation in treatment groups were respectively given the traditional decoction of D. officinale and 50% dose ultra-micro powder D. officinale. The metagenome DNA of intestinal flora was extracted from intestinal contents. Then ARDRA analysis was made after PCR by universal primer of bacteria. The results showed that OTUs, Shannon index and Brillouin index were the same between the normal group and the 50% dose ultra-micro powder group, and between the model group and the traditional decoction group, but greater in the former two groups than the latter ones. The similarity coefficient (0.500 0) was bigger between the 50% dose ultra-micro powder group and the normal group than between the model group and the traditional decoction group, which was 0.181 8. Both cluster analysis and principal components analysis showed that the molecular diversity of intestinal microbiotia in mice of 50% dose ultra-micro powder group was the closest to that in the normal group. The results showed that the weakened molecular diversity of intestinal bacteria in mice with spleen-deficiency constipation can be regulated by the two kinds of D. officinale treatments to different extent. The efficacy of 50% dose ultra-micro powder D. officinale is better than the traditional decoction. 相似文献
109.
110.
随着区域经济的发展和自然资源的开发,区域生态环境状况面临严峻的考验。本文分析了新疆天山北坡经济带的生态环境现状、特点及发展趋势,重点阐述了该区域生态环境保护与治理的思路,并提出一些相应的对策和建议。 相似文献