全文获取类型
收费全文 | 498篇 |
免费 | 16篇 |
国内免费 | 95篇 |
专业分类
安全科学 | 28篇 |
废物处理 | 33篇 |
环保管理 | 49篇 |
综合类 | 141篇 |
基础理论 | 83篇 |
污染及防治 | 215篇 |
评价与监测 | 29篇 |
社会与环境 | 23篇 |
灾害及防治 | 8篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 21篇 |
2021年 | 17篇 |
2020年 | 17篇 |
2019年 | 7篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 27篇 |
2013年 | 59篇 |
2012年 | 38篇 |
2011年 | 42篇 |
2010年 | 17篇 |
2009年 | 25篇 |
2008年 | 25篇 |
2007年 | 51篇 |
2006年 | 22篇 |
2005年 | 20篇 |
2004年 | 16篇 |
2003年 | 34篇 |
2002年 | 14篇 |
2001年 | 19篇 |
2000年 | 12篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 5篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有609条查询结果,搜索用时 366 毫秒
381.
对弥渡台地电场观测电极进行埋深处理,将原来埋深1.5 m电极深埋到5.0 m。改进后,三个测道长、短极距一致性较好,差值减少到个位数,相关性达到高度相关。通过电极埋深处理前后观测数据的对比分析认为:在地电场观测中,若将电极做深埋处理,则可以有效抑制来自地表干扰。 相似文献
382.
383.
基于可达、可行、可接受的全面小康社会环境目标研究 总被引:2,自引:2,他引:0
基于2020年我国经济社会发展情景,开展环境目标与其他目标发展协调性分析,认为环境指标负向发展突出,是全面小康社会的短板和最大制约因素。从需求侧和供给侧分析小康社会环境目标的政治、公众需求与政府的供给条件、基础和能力,通过新常态资源环境压力分析与环境质量改善国际对标研究,认为我国在社会经济发展方式转型尚未完成、环境治理投入没有持续明显提升的情况下,大幅度、全面改善环境质量还存在很大障碍。提出全面小康的环境目标定位应以环境质量为核心,响应公众对环境质量改善的期待;合理看待小康社会的历史定位,制定阶段性目标;把握生态环境可达、经济技术可行、人民群众可接受的平衡,综合确定全面小康社会的环境底线。全面小康环境目标设置应体现保底线、全覆盖、诉民生、有标杆等原则。 相似文献
384.
385.
Tropical estuary wetlands are important for aquaculture and wildlife. However, many of them receive large amounts of anthropogenic heavy metals annually. Here, the transformation of spiked heavy metals, namely, Cd, Cr, Cu, Ni, Pb, and Zn, and the effects of salinity on their transformation in wetland soils after an eight-month-long incubation under moisture-saturation conditions were studied in the Pearl River estuary in China. Cd exhibited high mobility and bioavailability, with 12.2% to 25% Cd existing in the exchangeable fraction. Other heavy metals primarily existed in the reducible and oxidisable forms, and less than 2% were bound to the exchangeable fraction. Compared with the controls, contents of none of the metals associated with residual forms were significantly altered. These results imply that most exchangeable metals, except for Cd, transformed into other stable fractions through an eight-month-long ageing process, but not into the residual fraction. Thus, transformation from non-residual to residual forms was very slow in the tropical estuary wetland environment. Addition of NaCl increased the exchangeable fractions of Cd, Pb, and Zn, suggesting that increased soil salinity induced by flood tides during the dry season may enhance their mobility. 相似文献
386.
近几年来人们普遍感到各种事故越来越多,尤其是恶性事故的频发率很高,造成重大的人员伤亡和财产损失愈发厉害,让人惊恐不安。据国家安全生产监督管理总局、监察部的通报,在2006年处理结案特别 相似文献
387.
In this study, we added increments of acid and base to three calcareous soils from the eastern, middle and western parts of Gansu Province (China) and to three treated soils to remove calcium carbonate, organic matter and both carbonate and organic matter, respectively. the titration curves were measured and the magnitudes of buffer capacities as a function of pH were computed. It was found that the buffer capacity of calcareous soil is mainly attributed to calcium carbonate, as expected from the chemical composition of calcareous soil, while cation exchange system, silicate buffer system and organic matter play a minor role. the results clearly show that these soils of Gansu Province will not become a problem in the near future from the entrance of H+ into these soils. 相似文献
388.
Wei Chu Shen Manhong . College of Economics Management Zhejiang Sci-Tech University Hangzhou Zhejiang China . College of Economics Zhejiang University Hangzhou Zhejiang China 《中国人口.资源与环境(英文版)》2007,5(2):28-33
This article developed a decomposition model of energy productivity on the basis of the economic growth model. Four factors were considered which may influence China’s energy productivity according to this model: technology improvement, resource allocation structure, industrial structure and institute arrangement. Then, an econometric model was employed to test the four factors empirically on the basis of China’s statistical data from 1978 to 2004. Results indicated that capital deepening con- tributes the most (207%) to energy efficiency improvement, and impact from labor forces (13%) is the weakest one in resource factor; industrial structure (7%) and institute innovation (9.5%) positively improve the energy productivity. 相似文献
389.
I Chu K M Ng F M Benoit D Moir 《Journal of environmental science and health. Part. B》1992,27(6):729-749
In the present study the biotransformation of phenanthrene in the rat and guinea pig was investigated. 14C-labelled phenanthrene was administered by gavage in corn oil to Sprague-Dawley rats (10 mg/kg b.w./day) and guinea pigs (10 mg/kg b.w./day). Urine and feces were separately collected for the determination of the radioactivity content, and pooled urine was used for the analysis of metabolites. Phenanthrene was metabolized by the rat and guinea pig to free hydroxylated phenanthrenes and their conjugates. The percentages of conjugates, expressed as the total urinary radioactivity, were 39% glucuronides, 24% sulfates and 18% cysteinylglycine for rats; and 39% glucuronides, 23% sulfates and 28% cysteinylglycine for guinea pigs. Enzymatic hydrolysis of glucuronides and sulfates resulted in the formation of free 1,2-, 3,4- and 9,10-dihydrodiols of phenanthrene and 1-, 2-, 3-, and 4-hydroxyphenanthrene in both species. 相似文献
390.
The fate of ochratoxin A (OA) was studied in goats given a single oral dose of 3H-OA (0.5 mg/kg). More than 90% of the radioactivity was found to be excreted in 7 days and the majority (53%) was found in feces. Thirty-eight percent, 6% and 2.26% of the activity was found in urine, milk and serum, respectively. The radioactivity in the liver and kidney 6 hours after feeding amounted to 1.5 and 0.5% of the total dose administered, respectively. Subsequent fractionation of liver and kidney homogenates revealed that microsomes, ribosomes and post-ribosomal supernatant fractions contained most radioactivity. Thin layer chromatographic analyses revealed two additional radioactive spots with Rf values and fluorescent characteristics different from OA, Oalpha and 4-OH-OA. Whereas OA was found as the unaltered molecule in feces, the metabolites were primarily found in urine and milk. Less than 0.03% of free OA was found in milk during the 7-day period. 相似文献