全文获取类型
收费全文 | 445篇 |
免费 | 27篇 |
国内免费 | 214篇 |
专业分类
安全科学 | 36篇 |
废物处理 | 35篇 |
环保管理 | 38篇 |
综合类 | 266篇 |
基础理论 | 85篇 |
污染及防治 | 159篇 |
评价与监测 | 25篇 |
社会与环境 | 18篇 |
灾害及防治 | 24篇 |
出版年
2023年 | 15篇 |
2022年 | 17篇 |
2021年 | 20篇 |
2020年 | 22篇 |
2019年 | 20篇 |
2018年 | 24篇 |
2017年 | 24篇 |
2016年 | 26篇 |
2015年 | 42篇 |
2014年 | 37篇 |
2013年 | 54篇 |
2012年 | 50篇 |
2011年 | 38篇 |
2010年 | 33篇 |
2009年 | 29篇 |
2008年 | 26篇 |
2007年 | 39篇 |
2006年 | 17篇 |
2005年 | 16篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 20篇 |
2001年 | 8篇 |
2000年 | 10篇 |
1999年 | 17篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
排序方式: 共有686条查询结果,搜索用时 31 毫秒
551.
从"阳光体育"助推学校体育管理变革出发,借鉴和运用利益相关者理论,分析我国学校体育管理变革的逻辑基础以及划分出不同的利益相关者,指出学校体育管理变革实质上就是各利益相关者之间利益博弈或行为协作的制度变迁过程,其结果是各利益相关者对学校体育资源及其附属品的再分配,其中利益冲突是变革的核心内容,而造成利益冲突的原因是多方面的。走向利益均衡是学校体育管理变革的基本价值取向。 相似文献
552.
Feng Li Xiang-yun Zeng Yun-jun Yu Chang-hua Wu Ge Mai Wei-wei Song Yan-mao Wen Zhi-peng Duan Jia-yu Yang 《Environmental monitoring and assessment》2014,186(8):4935-4946
Acid volatile sulfide (AVS) has been regarded as an important factor controlling metal bioavailability in anoxic sediments, but its effect on metal accumulation under natural conditions is poorly understood. Here, a field study of the influence of AVS on metal accumulation by Limnodrilus sp. in a heavily polluted river is provided. Most of the study area was subject to anaerobic and strongly reducing conditions, and the concentration of trace metals in surface sediments was high, as were the concentration of AVS and simultaneously extracted metals (SEM; average AVS?=?20.3 μmol g?1, average ∑SEM5?=?9.42 μmol g?1; ∑SEM5 refers to the sum of SEMCd, SEMCu, SEMPb, SEMNi, and SEMZn). Only a few species and small quantities of benthic invertebrates were found, and Limnodrilus sp. was dominant. There was no correlation between trace metal accumulation and (SEM-AVS), and in stations where (SEM-AVS) <0, the absolute value of bioaccumulation was high (average ∑BIO5?=?4.07 μmol g?1; ∑BIO5 refers to the sum of BIOCd, BIOCu, BIOPb, BIONi, and BIOZn), indicating that there was no relationship between (SEM–AVS) and metal accumulation in Limnodrilus sp. This was likely because Limnodrilus sp. ingest sediment particles as their main food source, so pore water metals play a minor role in their bioaccumulation (BIO) of materials. However, ∑BIO5 was significantly correlated with ∑SEM5 (r?=?0.795, p?<?0.01), revealing that the large number of sulfide-bound metals (SEM) in sediments may play an important role in metal accumulation in Limnodrilus sp., which can assimilate sulfide-associated metals by the help of the digestive fluids in the digestive systems. 相似文献
553.
Duan Huiming Luo Xilin 《Environmental science and pollution research international》2020,27(35):43884-43905
Environmental Science and Pollution Research - Energy saving and emission reduction are the most concerned issues in the world. Objective and accurate prediction of carbon emissions can provide... 相似文献
554.
Environmental significance of biogenic elements in surface sediments of the Changjiang Estuary and its adjacent areas 总被引:5,自引:0,他引:5
Biogenic elements and six phosphorus(P) fractions in surface sediments from the Changjiang Estuary and adjacent waters were determined to investigate the governing factors of these elements, and further to discuss their potential uses as paleo-environment proxies and risks of P release from sediment. Total organic carbon(TOC) and leachable organic P(Lea-OP) showed high concentrations in the estuary, Zhejiang coast and ofshore upwelling area. They came from both the Changjiang River and marine biological input.Biogenic silicon(BSi) exhibited a high concentration band between 123 and 124°E. BSi mainly came from diatom production and its concentration in the inshore area was diluted by river sediment. Total nitrogen(TN) was primarily of marine biogenic origin. Seaward decreasing trends of Fe-bound P and Al-bound P revealed their terrestrial origins. Influenced by old Huanghe sediment delivered by the Jiangsu coastal current, the maximum concentration of detrital P(Det-P) was observed in the area north of the estuary. Similar high concentrations of carbonate fluorapatite(CFA-P) and CaCO3 in the southern study area suggested marine calcium-organism sources of CFA-P. TOC, TN and non-apatite P were enriched in fine sediment, and Det-P partially exhibited coarse-grain enrichment, but BSi had no correlation with sediment grain size. Diferent sources and governing factors made biogenic elements and P species have distinct potential uses in indicating environmental conditions. Transferable P accounted for 14%-46% of total P. In an aerobic environment,there was low risk of P release from sediment, attributed to excess Fe oxides in sediments. 相似文献
555.
本文以畜禽养殖较为集中、污染问题较为突出的辽河源头区为研究区域,通过流域内畜禽污染物排放方式,污染物排放总量,总结流域内畜禽养殖污染特点,在次基础上提出切实可行的畜禽污染防治对策,为相关政策的制定提供依据。 相似文献
556.
557.
The removal of four dissolved organic matter (DOM) fractions, non-acid hydrophobics, hydrophobic acids, hydrophilics and transphilics, was achieved by coagulation-UV/H2O2 oxidation in post-pharmaceutical wastewater (PhWW). Coagulation with Polyferric chloride (PFC), Polymeric ferric sulfate (PFS) and Polymeric aluminum ferric chloride (PAFC) was studied separately to evaluate the effects of the initial pH and coagulant dosage. The coagulation-UV/H2O2 oxidation method resulted in much higher reduction rates for dissolved organic carbon (DOC) (by 75%) and UV254 (by 92%) than coagulation or UV/H2O2 oxidation alone. The proportion of non-acid hydrophobics, hydrophobic acids, transphilics and hydrophilics removed by coagulation was 54%, 49%, 27% and 12 %, while the combined treatment removed 92%, 87%, 70% and 39%, respectively. Parallel factor analysis (PARAFAC) of fluorescence measurements revealed that the humic-like fluorescent component C4 showed the highest removal (by 44%) during the coagulation stage. After coagulation-UV/H2O2 treatment, the humic-like fluorescent component C3 had the highest removal (by 72%), whereas xenobiotic organic fluorescent components C1 and C4 remained recalcitrant to decomposition. Significant correlations (R2 > 0.8) between C1 and the hydrophobic acids and non-acid hydrophobics suggested the possibility of using fluorescence spectroscopy as an effective tool to assess variations in DOM fraction treatment efficacy in coagulation-UV/H2O2 systems. After the combined treatment, toxic inhibition of cellular activity by post PhWW decreased from 88% to 47% and biodegradability increased from 0.1 to 0.52. 相似文献
558.
石墨炉原子吸收分光光度法测定土壤中总铬 总被引:1,自引:0,他引:1
建立了土壤中总铬测定的石墨炉原子吸收分光光度法;以塞曼效应扣除背景,优化了石墨炉灰化、原子化温度、停留时间及基体改进剂用量。结果表明:当原子化温度为2 700℃,灰化温度为700℃,原子化时间2 s,灰化时间为9 s;基体改进剂用量为3~5μL时,仪器可以达到最佳工作状态。该方法铬元素浓度在0~32μg/L内呈良好的线性关系,相关系数r=0.999 9,检出限为0.3 mg/kg;对土壤标样GSS-1和ESS-1的铬测定精密度均小于5%,相对误差在-4.8%~-0.7%之间,方法的灵敏度和准确度均符合要求。因此,石墨炉原子吸收分光光度法测定土壤中总铬具有原子化温度高、干扰少、灵敏度高等特点可适用土壤中总铬的测定。 相似文献
559.
560.
清洁发展机制中的额外性问题探讨 总被引:10,自引:0,他引:10
清洁发展机制(CDM)是国际社会应对全球气候变化所作努力的一个重要部分。就清洁发展机制实施中的关键问题之一——额外性问题(additionality)进行了细致的探讨。分析了额外性的基本含义,各个不同国家在这个问题上的观点,各种不同判断准则的合理性和可操作性等。提出了额外性的层次等重要概念。 相似文献