全文获取类型
收费全文 | 2087篇 |
免费 | 307篇 |
国内免费 | 886篇 |
专业分类
安全科学 | 206篇 |
废物处理 | 63篇 |
环保管理 | 556篇 |
综合类 | 1628篇 |
基础理论 | 300篇 |
污染及防治 | 228篇 |
评价与监测 | 161篇 |
社会与环境 | 64篇 |
灾害及防治 | 74篇 |
出版年
2024年 | 13篇 |
2023年 | 65篇 |
2022年 | 107篇 |
2021年 | 121篇 |
2020年 | 106篇 |
2019年 | 105篇 |
2018年 | 86篇 |
2017年 | 122篇 |
2016年 | 143篇 |
2015年 | 166篇 |
2014年 | 174篇 |
2013年 | 231篇 |
2012年 | 227篇 |
2011年 | 188篇 |
2010年 | 127篇 |
2009年 | 114篇 |
2008年 | 97篇 |
2007年 | 170篇 |
2006年 | 119篇 |
2005年 | 117篇 |
2004年 | 80篇 |
2003年 | 95篇 |
2002年 | 68篇 |
2001年 | 56篇 |
2000年 | 49篇 |
1999年 | 48篇 |
1998年 | 37篇 |
1997年 | 37篇 |
1996年 | 32篇 |
1995年 | 29篇 |
1994年 | 26篇 |
1993年 | 18篇 |
1992年 | 8篇 |
1991年 | 12篇 |
1990年 | 5篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 16篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1982年 | 2篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有3280条查询结果,搜索用时 15 毫秒
41.
42.
阳离子表面活性剂与二甲酚橙在pH7~8的溶液中发生显色反应,用修正光度法处理,能消除空白干扰,提高分析灵敏度,该方法检出限为0.08mg/L,线性范围0~15mg/L,加标回收率96%~102%,适于环境痕量分析。 相似文献
43.
本文介绍了一种新型的过滤技术(表面过滤技术)在袋式除尘器中的应用及其特点,该技术的采用可减少除尘器的压力损失,提高滤袋的使用寿命和除尘效率. 相似文献
44.
45.
ThebufferingeffectsofaquaticsedimentsagainstacidicdepositionLiaoBohan;TangHongxiao(ResearehCenterforEco-EnvironmentalSciences... 相似文献
46.
Spatial variations in daily average CO2 concentrations above wetland surface of Xianghai National Nature Reserve, China 总被引:1,自引:0,他引:1
Horizontal and vertical variations of daily average CO2 concentration above the wetland surface were studied in Xianghai National Nature Reserve of China in August, 2000. The primary purpose was to study spatial distribution characteristics of CO2 concentration on the four levels of height(0.1 m, 0.6 m, 1.2 m and 2 m) and compare the differences of CO2 concentration under different land covers. Results showed that daily average CO2 concentration above wetland surface in Xianghai National Natural Reserve was lower than that above other wetlands in northeast China as well as the worldwide average, suggesting that Xianghai wetland absorbed CO2 in August and acted as“sink” of CO2. The horizontal variations on the four levels of height along the latitude were distinct, and had the changing tendency of“decreasing after increasing” with the increase of height. The areas with obvious variations were consistent on different levels of height,and those with the highest variations appeared above surface of shore, sloping field, Typha wetland and Phragmites wetland; the vertical variations were greatly different, with the higher variations in Phragmites wetland and Typha wetland, and the lands near the shore and the sloping field with the lower variations. Spatial variations of daily average CO2 concentrations above wet!and surface were affected by surface qualities and land covers. 相似文献
47.
48.
49.
A de novo paracentric inversion of chromosome 11 identified through antenatal diagnosis is described along with long-term follow-up information on the child and discussion of reported experiences with de novo inversions. 相似文献
50.
In this study,the surface properties and adsorption properties of the Le An River sediment were modelled via surface complexation approach.The model parameters were determined based on the data of our potentiometric titration experiments and the metal adsorption experiments with the Le An River sediment samples.Consequently,the surface complexation models for the natural sediment,in our case the Le An River sediments,which can interpret the experimental data very well were successfully established.Three typical surface complexation models that is the constant capacitance model,the diffuse layer model and the triple layer model,were considered in this research.This work indicated that the consistency and the interdependency among model parameters together with the selection of the surface adsorbed species should be emphasized. 相似文献