全文获取类型
收费全文 | 2703篇 |
免费 | 156篇 |
国内免费 | 1254篇 |
专业分类
安全科学 | 216篇 |
废物处理 | 150篇 |
环保管理 | 179篇 |
综合类 | 1691篇 |
基础理论 | 482篇 |
污染及防治 | 1062篇 |
评价与监测 | 140篇 |
社会与环境 | 92篇 |
灾害及防治 | 101篇 |
出版年
2024年 | 5篇 |
2023年 | 60篇 |
2022年 | 161篇 |
2021年 | 125篇 |
2020年 | 111篇 |
2019年 | 97篇 |
2018年 | 120篇 |
2017年 | 138篇 |
2016年 | 172篇 |
2015年 | 200篇 |
2014年 | 236篇 |
2013年 | 298篇 |
2012年 | 245篇 |
2011年 | 227篇 |
2010年 | 177篇 |
2009年 | 185篇 |
2008年 | 200篇 |
2007年 | 178篇 |
2006年 | 157篇 |
2005年 | 122篇 |
2004年 | 86篇 |
2003年 | 99篇 |
2002年 | 78篇 |
2001年 | 90篇 |
2000年 | 74篇 |
1999年 | 88篇 |
1998年 | 68篇 |
1997年 | 45篇 |
1996年 | 44篇 |
1995年 | 64篇 |
1994年 | 41篇 |
1993年 | 35篇 |
1992年 | 25篇 |
1991年 | 20篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1976年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有4113条查询结果,搜索用时 0 毫秒
961.
962.
A new method for the determination of iron, cobalt, nickel, copper, zinc and manganese in drinking water by the reversed-phase high-performance liquid chromatography (RP-HPLC) with 2-(2-quinolinylazo)-5-diethylaminophenol (QADEAP) as precolumn derivatizing reagent was studied in this paper. The iron, cobalt, nickel, copper, zinc, and manganese ions react with QADEAP to form color chelates in the presence of cetyl trimethylammonium bromide (CTMAB) and acetic acid-sodium acetic buffer solution medium of pH 4.0. These chelates were enriched by solid-phase extraction with a Waters Nova-Pak C18 cartridge and eluted the retained chelates from the cartridge with tetrahydrofuran (THF). The enrichment factor of 100 was achieved. Then the chelates were separated on a Waters Nova-Pak C18 column (3.9 x 150 mm, 5 microm) by gradient elution with methanol (containing 0.2% of acetic acid and 0.1% of CTMAB) and 0.05 mol L(-1) acetic acid-sodium acetic buffer solution (containing 0.1% of CTMAB) (pH 4.0) as mobile phase at a flow rate of 0.5 ml min(-1), and monitored with a photodiode array detector from 450 approximately 700 nm. The detection limits (S/N = 3) of iron, cobalt, nickel, copper, zinc and manganese are 0.8, 1.1, 0.9, 1.1, 1.5 and 2.0 ng L(-1), respectively, in the original sample. This method can be applied to determination at the microg L(-1) level of iron, cobalt, nickel, copper, zinc and manganese in drinking water with good results. 相似文献
963.
本文从工程地质观点出发,分析汉江上游斜坡一带的天然地质条件及其斜坡破坏的基本形式和原因,从理论上探讨由于经济-工程活动而引起其在天然地质过程方面的变异及效应这一环境工程地质问题。 相似文献
964.
A study was conducted to investigate the effect of organic acids on Cd and Cu desorption from natural contaminated soils (NCS) with permanent contamination by metal smelters and from artificial contaminated soils (ACS) derived from an artificial amendment of Cd to three representative zonal soils in Central China. Results showed that the desorption of Cd in either NCS or ACS, with the increment of tartrate or citrate concentration in desorption solution, can be characterized as a valley-like curve. The presence of tartrate or citrate at a low concentration (< or =0.5 mmol/l) inhibited Cd desorption from these two types of soils, whereas the presence of organic acids at high concentrations (> or =2 mmol/l for citrate and about > or =15 mmol/l for tartrate) apparently promoted Cd desorption. The desorption curve of Cu by tartrate solution with different tartrate concentrations can also be characterized as a valley-like curve, while the desorption of Cu in the presence of citrate was directly enhanced with the increment of citrate concentration. With the enhancement of initial pH value from 2 to 8 in the presence of citrate, Cu desorption ratio decreased at the first stage, then increased, and then decreased again. A valley and a peak sequentially appeared in the Cd or Cu desorption curve with initial pH value increment. Compared with citrate, the desorption ratio of Cd or Cu from NCS or ACS was directly decreased in the presence of tartrate, with the enhancement of the pH value from 2 to 8. Cd or Cu desorption was clearly enhanced when the electrolyte concentration of KNO3 or KCl increased in the presence of 2 mmol/l tartrate. Moreover, a higher desorption ratio of Cd or Cu was shown with KCl electrolyte than with KNO3 electrolyte with the same concentration. Based on these observations, we suggest that bioavailabilities of heavy metal can be promoted with selected suitable types and concentrations of organic acid amendment and reasonable field condition. 相似文献
965.
Abstract Dramatic economic and social changes have taken place in Jiangyin city due to rapid and uneven urbanization and industrialization. The environmental degradation has followed driven by these changes since the 1980's. With the pressures and effects of environmental deterioration, the city has implemented environmental management to hold back the trends of negative environmental changes. From the viewpoint of systems, DPSER is a good model for urban environmental changes to understand the causes, pressure, state, effect, existing responses and future action strategies. We took Jiangyin city, a developed city in South Jiangsu province, East China, as an example, and analyzed the characteristics of environmental changes and urban responses using DPSER model. Some operational strategies have been put forward to direct the city environmental management towards a sustainable road step by step. 相似文献
966.
分析了监测县涝洼农区发展节粮型畜牧业的有利条件和存在的问题,提出了充分利用本地自然资源,发展节粮型畜牧业的对策。 相似文献
967.
968.
969.
从农药厂阿特拉津生产车间污泥中分离出菌种AT菌,进行了系列降解实验.不同温度的降解实验表明,在4~20℃的实验温度范围内,AT菌能够降解代谢污染质,并随温度的升高,降解能力增强.20℃时降解率为38.84%;AT菌在外加氮源、碳源及以阿特拉津为惟一碳源和氮源等条件时对农药污染质阿特拉津均具有降解能力,且在以阿特拉津为惟一氮源(外加碳源)条件下的降解效果最好,此时的降解率为30.39%. 相似文献
970.
利用生态混凝土作为护坡材料,研究暴雨条件下生态混凝土控制山坡降雨径流污染的机理,以期对生态混凝土在城市护坡和护岸中的应用提供理论依据.研究结果表明,生态混凝土改变了雨水在坡面上的水文过程,阻延径流作用十分明显,有效地降低了污染物的负荷输出.生态混凝土试验小区(T2)与裸地(CK)和改良土壤小区(T1)相比,径流量分别减少了48%和24%,TN年度污染负荷(UPLRs)分别减少了53%和45%,溶解态氮(DN)减少了26%和28%,TP减少了57%和30%,溶解态磷(DP)降低了80%和33%,COD降低了62%和40%,TSS降低了56%和43%,产流时间和流量峰均明显滞后.另外,同植被覆盖良好的小区(T3)相比,生态混凝土对各种污染指标的控制效果没有明显差异,但其抗冲刷能力较强,更能适应城市护坡和护岸的需要. 相似文献