全文获取类型
收费全文 | 2952篇 |
免费 | 208篇 |
国内免费 | 576篇 |
专业分类
安全科学 | 233篇 |
废物处理 | 55篇 |
环保管理 | 346篇 |
综合类 | 1655篇 |
基础理论 | 682篇 |
污染及防治 | 354篇 |
评价与监测 | 122篇 |
社会与环境 | 129篇 |
灾害及防治 | 160篇 |
出版年
2024年 | 10篇 |
2023年 | 27篇 |
2022年 | 76篇 |
2021年 | 82篇 |
2020年 | 80篇 |
2019年 | 62篇 |
2018年 | 67篇 |
2017年 | 69篇 |
2016年 | 59篇 |
2015年 | 80篇 |
2014年 | 106篇 |
2013年 | 148篇 |
2012年 | 124篇 |
2011年 | 309篇 |
2010年 | 184篇 |
2009年 | 126篇 |
2008年 | 95篇 |
2007年 | 107篇 |
2006年 | 99篇 |
2005年 | 73篇 |
2004年 | 304篇 |
2003年 | 343篇 |
2002年 | 149篇 |
2001年 | 115篇 |
2000年 | 111篇 |
1999年 | 126篇 |
1998年 | 70篇 |
1997年 | 146篇 |
1996年 | 51篇 |
1995年 | 42篇 |
1994年 | 44篇 |
1993年 | 87篇 |
1992年 | 71篇 |
1991年 | 50篇 |
1990年 | 8篇 |
1989年 | 18篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1979年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有3736条查询结果,搜索用时 203 毫秒
81.
82.
LevelofcoordinateddevelopmentineconomyandenvironmentZhangQide,WangYuxiu,RenJinsongLiaoningInstituteofEnvironmentProtectionSci... 相似文献
83.
A mathematical model relating to the change in phytoplankton biomass in the period of growth and nutrient concentration in the media was proposed on the basis of the Monod equation and was testified by simulation experiments. Analysis of the experiment data showed that: the half-saturation constants for growth Kp (μmol/L) for Skeletonema, Chaetoceros and Prorocentrum were 5.52, 1.90 and 0.46, respectively; the balance between stimulation of nutrients and the inhibition of some other materials was found in the effect of domestic sewage on algal growth and the stimulation played a leading role; domestic sewage was more stimulative on dinoflag-ellate than on diatom and chlorophyte when the assemblage of the algae was cultured. The experiment suggested that mathematical model reasonably explained the characteristics of phytoplankton growth in different nutrient conditions and was worthy to be further improved for eutrophication prediction in off-shore water. 相似文献
84.
A result that application of sodium selenite or fly ash to some of soilin loess plateau can increase Se content in wheat grain has been demonstrated by the pot and field experiments, and added Se in soil can last its availability for 3 years. So this is a good measure for improving the low Se soils and preventing the Kaschin-Beck disease. 相似文献
85.
环境问题的实质,就是人类从环境中索取资源的速度超过了资源本身及其替代品的再生速度,即向环境排放废弃物的速度超过了环境的自净能力,自然和人文景观受到破坏,环境对废弃物的消纳同化能力越来越弱,环境功能发生退化,环境资源失去了可持续性。 相似文献
86.
87.
魔芋葡甘聚糖在污水处理中的应用 总被引:4,自引:0,他引:4
该文就魔芋葡甘聚糖的发展研究状况作了概述,并探讨其与蛋白质共混胶应用于水处理的可能性。 相似文献
88.
A stopped-flow reversed flow injection method for the determination of free cyanide is proposed. Pyridine-barbituric acid mixture is injected in the flow system as reagent to form the colour species with cyanide. The flow is stopped when the reagent zone comes in the flow cell, where absorbance-time data are collected at 580nm wavelength. The linear range of the determination is 0.1 -10μg/ml CN-. The sampling rate is 60h-1 and the relative standard deviation is 1.6% (n=16) at 5.0 μg/ml CN-1 level. With satisfactory results, the proposed method was applied to the determination of free cyanide in wastewater without sample pretreatment. 相似文献
89.
Epidemiological survey of 573 families, clinical examination of 2593 persons, and X-ray examination of 1136 persons (in 16 typical endemic villages) were conducted, based on the classification of endemiology for KBD disease areas, i.e, mountain type, loess plateau type, plateau type, and flatlands type. It was revealed that the KBD disease areas exhibited the regular pattern of corming-into-being, development and passing-away and the characteristics of growth and decline. Further, it was found clinically that the disease areas may be divided into 4 types, i.e., recent onset, developing, stable, and historical. This division is simple and easy, practical, scientific, and reliable and can be applied by medical personnel at different levels. 相似文献
90.
在上海某典型街道内设置一测点,在一定时段内进行超细颗粒物测试分析,同时记录车辆种类、车流量、气象条件等,分析街道内机动车排放颗粒物的分布情况,研究颗粒物的扩散规律与车流量,风速、风向等的关系.研究表明:颗粒物数量浓度粒径分布多呈双峰分布,数量浓度峰值大都在105particles/cm3以上,总数量浓度在(1~9)×106 particles/cm3之间,与欧美发达国家相比,机动车车况较差,机动车排放污染较严重.另外,颗粒物总数量平均浓度随风速的增大而减小,颗粒物几何平均粒径随风速的增大而增大. 相似文献