全文获取类型
收费全文 | 13758篇 |
免费 | 943篇 |
国内免费 | 1685篇 |
专业分类
安全科学 | 2681篇 |
废物处理 | 578篇 |
环保管理 | 1230篇 |
综合类 | 8023篇 |
基础理论 | 1010篇 |
污染及防治 | 1134篇 |
评价与监测 | 1077篇 |
社会与环境 | 295篇 |
灾害及防治 | 358篇 |
出版年
2024年 | 89篇 |
2023年 | 322篇 |
2022年 | 374篇 |
2021年 | 507篇 |
2020年 | 412篇 |
2019年 | 443篇 |
2018年 | 309篇 |
2017年 | 338篇 |
2016年 | 434篇 |
2015年 | 551篇 |
2014年 | 1048篇 |
2013年 | 722篇 |
2012年 | 807篇 |
2011年 | 789篇 |
2010年 | 626篇 |
2009年 | 626篇 |
2008年 | 709篇 |
2007年 | 737篇 |
2006年 | 655篇 |
2005年 | 640篇 |
2004年 | 617篇 |
2003年 | 706篇 |
2002年 | 556篇 |
2001年 | 420篇 |
2000年 | 340篇 |
1999年 | 292篇 |
1998年 | 319篇 |
1997年 | 299篇 |
1996年 | 277篇 |
1995年 | 281篇 |
1994年 | 213篇 |
1993年 | 179篇 |
1992年 | 156篇 |
1991年 | 175篇 |
1990年 | 224篇 |
1989年 | 187篇 |
1988年 | 3篇 |
1987年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
991.
992.
993.
994.
995.
为了解北京城区大气干沉降中水溶性离子的化学组成与时间变化特征,连续进行了4年多的干沉降采样与分析.结果表明,在222个有效干沉降样品中,存在不同程度的阴离子缺失. SO42-与Ca2+分别是含量最丰富的阴、阳离子组分,其次是NO3-和NH4+. SO42-、NO3-和NH4+呈现相似的季节变化特征,即其浓度在夏季最高,冬季最低. 干沉降基本呈中性,其pH值月变化幅度小,但季节变化明显,夏季低而春季高. 相似文献
996.
997.
998.
针对大蒜废水特点,采用了铁屑微电解-UASB-接触氧化工艺进行处理.运行结果表明:在设计进水水质、水量范围内,COD、BOD5、氨氮和ss去除率分别为98%、99%、70%和98%,出水各项指标均达到GB 8978--1996<污水综合排放标准>中的一级排放标准,系统运行费用为1.19元/m3. 相似文献
999.
Yanhui Li Bing Xi Quansheng Zhao Fuqiang Liu Pan Zhang Qiuju Du Dechang Wang Da Li Zonghua Wang Yanzhi Xia 《环境科学学报(英文版)》2011,23(3):404-411
Kaolin has been widely used as an adsorbent to remove heavy metal ions from aqueous solutions. However, the lower heavy metal
adsorption capacity of kaolin limits its practical application. A novel environmental friendly material, calcium alginate immobilized
kaolin (kaolin/CA), was prepared using a sol-gel method. The e ects of contact time, pH, adsorbent dose, and temperature on Cu2+
adsorption by kaolin/CA were investigated. The Langmuir isotherm was used to describe the experimental adsorption, the maximum
Cu2+ adsorption capacity of the kaolin/CA reached up to 53.63 mg/g. The thermodynamic studies showed that the adsorption reaction
was a spontaneous and endothermic process. 相似文献
1000.
Chemical forms of Zn, Ni, Cu, and Pb in municipal sewage sludge were investigated by adding humus soil to sludge and by
performing sequential extraction procedures. In the final sludge mixtures, Zn and Ni were mainly found in Fe/Mn oxide-bound (F3) and
organic matter/sulfide-bound (F4) forms. For Zn, exchangeable (F1), carbonate-bound (F2), and F3 forms were transformed to F4 and
residual forms (F5). For Ni, F1 and F2 forms were transformed to F1, F2, and F3 forms. Both Cu and Pb were strongly associated with
the stable forms F4 and F5. For Cu, F2 and F3 forms were major contributors, while for Pb, F3 and F4 forms were major contributors to
F5. Humus soil dosage and pH conditions in the sludge were strongly correlated with the forms of heavy metals. Five forms were used
to evaluate metal mobilities in the initial and final sludge mixtures. The mobilities of the four heavy metals studied decreased after 28
days. The metal mobilities in the final sludge mixtures were ranked in the following order: Ni > Zn > Cu = Pb. Leaching tests showed
that the mobilities of Zn and Ni in lower pH conditions (pH 4) were higher than those in higher pH conditions (pH 8). 相似文献