全文获取类型
收费全文 | 3895篇 |
免费 | 332篇 |
国内免费 | 1446篇 |
专业分类
安全科学 | 394篇 |
废物处理 | 190篇 |
环保管理 | 281篇 |
综合类 | 2518篇 |
基础理论 | 684篇 |
环境理论 | 1篇 |
污染及防治 | 1014篇 |
评价与监测 | 214篇 |
社会与环境 | 192篇 |
灾害及防治 | 185篇 |
出版年
2024年 | 23篇 |
2023年 | 95篇 |
2022年 | 275篇 |
2021年 | 206篇 |
2020年 | 211篇 |
2019年 | 172篇 |
2018年 | 182篇 |
2017年 | 209篇 |
2016年 | 203篇 |
2015年 | 224篇 |
2014年 | 275篇 |
2013年 | 388篇 |
2012年 | 362篇 |
2011年 | 368篇 |
2010年 | 266篇 |
2009年 | 270篇 |
2008年 | 314篇 |
2007年 | 234篇 |
2006年 | 234篇 |
2005年 | 160篇 |
2004年 | 107篇 |
2003年 | 113篇 |
2002年 | 103篇 |
2001年 | 79篇 |
2000年 | 87篇 |
1999年 | 82篇 |
1998年 | 78篇 |
1997年 | 59篇 |
1996年 | 60篇 |
1995年 | 57篇 |
1994年 | 25篇 |
1993年 | 33篇 |
1992年 | 41篇 |
1991年 | 27篇 |
1990年 | 12篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有5673条查询结果,搜索用时 218 毫秒
611.
612.
Cai Jinlu 《环境科学学报(英文版)》1991,3(1):117-124
Over 2 million tons of chromate residues as hazardous wastes have been accumulated from chromate production processes during the past more than 30 years in China. Some serious pollution problems have been caused due to no appropriate technology and management. Approaches are reviewed to pollution control of chromate residues by utilizing them as secondary resources in this paper. In addition to legislation for pollution control, chromate residues can be used as raw materials to produce a great diversity of useful industrial products. Strategies are also recommanded for the resourcefulization of chromate residues. 相似文献
613.
本文通过对《立体构成》课程教学对象的分析,探讨了该课程在理论与实践教学环节教学方法的改进。实践证明,这些改进对于充分发掘学生潜力,激发学生的求知欲望,提高教师业务水平,促进《立体构成》课程教学改革具有重要意义。 相似文献
614.
615.
The photocatalytic oxidation of pyrene preadsorbed on TiO2 is examined in aqueous suspension under UV irradiation. Chemical oxygen demand measurements, UV-VIS spectrophotometer, infrared spectrometer and GC-MS analytical techniques were used to monitor the formed intermediates. During the oxidation processes, the ring-open reaction, hydroxylation and ketolysis occurred to produce some intermediate products (4-oxapyrene-5-one, 1,6- or 1,8-pyrenediones, 4,5-phenanthrenedialdehyde, cyclopenta[def]phenanthrene). Some factors affecting the photodegradation rate were also studied. The results were different from other studies: The pH of the dispersion, ratio of Py/TiO2:water had little effect on the photooxidation rate of pyrene catalyzed by TiO2, while the surface coverage, addition of Fe3+ affected it greatly. 相似文献
616.
Study on the kinetics of cerium(III) adsorption-desorption on different soils of China 总被引:1,自引:0,他引:1
The kinetics of Ce(III) adsorption-desorption on four typical soils in China has been studied by using the batch method with the radioactive nuclide 141Ce. Results indicated that Ce(III) adsorption was rapid and nearly finished in less than 0.5 min. Desorption procedure was about completed in 1-30 min in the tested soils. Ce(III) desorption equilibrium times vary with different soils. The amounts of Ce(III) desorption on different soils in the same time were different. The Elovich equation proved to be the best models for fitting the data of Ce(III) desorption reactions in fluvo-aquic soil and black soil; and the parabolic-diffusion equation was the best model in red earth and loess soil. 相似文献
617.
In the present study, a hydrophilic bifunctional polymeric resin (LS-2) with sulfonic groups was synthesized, and the adsorption performance of three aniline compounds, aniline, 4-methylaniline, and 4-nitroaniline onto LS-2 was compared with that on the commercial Amberlite XAD-4. The uptake of the aniline compounds on LS-2 is a procedure of coexistence of physisorption and chemisorption and obeys the pseudo-second order rate equation, while the uptake of the compounds on XAD-4 is merely a physical adsorption and follows the pseudo-first order rate equation. All the isothermal data fit well with the Freundlich model, and the values of K(F) of the compounds adsorbing on LS-2 are much higher than those on XAD-4 suggesting the higher adsorbing capacities on LS-2 than those on XAD-4, which may be attributed to the microporous structure and the polar groups on the network of LS-2 resin. Dynamic adsorption and desorption studies for aniline on LS-2 show that the breakthrough adsorption capacity and the total adsorption capacity are 0.96 and 1.24 mmol per milliliter resin, respectively. Nearly 100% regeneration efficiency for the adsorbent was achieved by 5% hydrochloric acid. 相似文献
618.
Degradation of 4-chlorophenol by microwave irradiation enhanced advanced oxidation processes 总被引:3,自引:0,他引:3
In this work the synergistic effects of several microwave assisted advanced oxidation processes (MW/AOPs) were studied for the degradation of 4-chlorophenol (4-CP). The efficiencies of the degradation of 4-CP in dilute aqueous solution for a variety of AOPs with or without MW irradiation were compared. The results showed that the synergistic effects between MW and H2O2, UV/H2O2, TiO2 photocatalytic oxidation (PCO) resulted in a high degradation efficiency for 4-CP. The potential of MW/AOPs for treatment of industrial wastewater is discussed. 相似文献
619.
采用厌氧 缺氧SBR反应器对以硝酸盐作为电子受体的反硝化除磷过程进行了研究。结果表明 ,反硝化聚磷菌完全可以在厌氧 缺氧交替运行条件下得到富集。稳定运行的厌氧 缺氧SBR反应器的反硝化除磷效率 >90 % ,出水磷浓度 <1mg L。进水COD浓度对反硝化除磷的效率影响很大 ,在COD浓度 <180mg L时 ,进水COD浓度越高 ,除磷效率也就越高。较高浓度的进水COD浓度将导致有剩余的COD进入缺氧段 ,对反硝化吸磷构成不利影响。污泥龄为 16d时 ,厌氧 缺氧SBR反应器取得稳定和理想的反硝化除磷效果。污泥龄减少到 8d ,由于反硝化聚磷菌的流失导致反硝化除磷效率的下降。当污泥龄恢复到 16d时 ,经过一段时间的运行 ,反硝化聚磷菌重新得到富集 ,除磷效率恢复到 90 %以上。 相似文献
620.
Dyer SD Peng C McAvoy DC Fendinger NJ Masscheleyn P Castillo LV Lim JM 《Chemosphere》2003,52(1):43-53
A risk assessment of chemical constituents in rivers that receive untreated wastewater should take into account the adverse effects of increased biological oxygen demand (BOD), ammonia and reduced dissolved oxygen (DO). This concept was tested via a field study in the Balatuin River, The Philippines, where the influence of physical and chemical factors, including the consumer product chemical linear alkylbenezene sulfonate (LAS), to aquatic communities (algae, invertebrates, fish) was determined. Periphytic algae were found to be insensitive to high BOD (>10 mg/l) and ammonia (>0.01 mg unionized NH(3)/l), concentrations from organically enriched untreated wastewater discharges. However, taxa richness and abundance of macroinvertebrates were influenced greatly by the discharges. Where BOD and ammonia concentrations were elevated, the dominant taxa were oligochaete worms and chironominds. Fish and crustaceans (freshwater crabs and prawns) were found only in sites with the least BOD concentrations (furthest upstream and downstream). The maximum concentration of LAS (0.122 mg/l) was less than that expected to affect 5% of taxa (0.245 mg/l), whereas exceedences of DO and ammonia criteria were observed in several sites. The lack of recovery observed was attributed to influences of low DO, high ammonia and poor colonization from upstream and downstream reaches due to organically-enriched discharges 相似文献