全文获取类型
收费全文 | 4012篇 |
免费 | 252篇 |
国内免费 | 821篇 |
专业分类
安全科学 | 306篇 |
废物处理 | 68篇 |
环保管理 | 994篇 |
综合类 | 2107篇 |
基础理论 | 587篇 |
环境理论 | 1篇 |
污染及防治 | 320篇 |
评价与监测 | 131篇 |
社会与环境 | 523篇 |
灾害及防治 | 48篇 |
出版年
2024年 | 28篇 |
2023年 | 55篇 |
2022年 | 118篇 |
2021年 | 121篇 |
2020年 | 141篇 |
2019年 | 149篇 |
2018年 | 131篇 |
2017年 | 205篇 |
2016年 | 216篇 |
2015年 | 210篇 |
2014年 | 198篇 |
2013年 | 286篇 |
2012年 | 284篇 |
2011年 | 353篇 |
2010年 | 250篇 |
2009年 | 241篇 |
2008年 | 200篇 |
2007年 | 295篇 |
2006年 | 247篇 |
2005年 | 183篇 |
2004年 | 155篇 |
2003年 | 183篇 |
2002年 | 127篇 |
2001年 | 94篇 |
2000年 | 99篇 |
1999年 | 85篇 |
1998年 | 48篇 |
1997年 | 40篇 |
1996年 | 37篇 |
1995年 | 31篇 |
1994年 | 24篇 |
1993年 | 23篇 |
1992年 | 19篇 |
1991年 | 16篇 |
1990年 | 14篇 |
1989年 | 15篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 12篇 |
1984年 | 8篇 |
1983年 | 11篇 |
1981年 | 16篇 |
1980年 | 18篇 |
1979年 | 13篇 |
1978年 | 7篇 |
1977年 | 12篇 |
1975年 | 9篇 |
1972年 | 5篇 |
1971年 | 7篇 |
排序方式: 共有5085条查询结果,搜索用时 15 毫秒
31.
液相加热法制备了Al2O3作为光催化剂,研究了不同光源、光照时间、催化剂用量和溶液酸度等条件对常见有机染料光催化降解性能影响。结果表明,用太阳光作为光源照射3h,50mL染料溶液中加入Al2O3 30mg,溶液pH8~10,孔雀石绿,酚藏花红,甲基紫等染料脱色率达93%以上。将使用过的Al2O3经过简单处理,孔雀石绿溶液脱色率仍达到94.1%,催化性能稳定,可以重复利用。通过紫外可见光谱分析,表明染料分子在催化剂和光照条件下发生了降解。 相似文献
32.
33.
34.
介绍工业生态学中生态效益的基本概念、核心思想和企业向生态效益型发展的必要性和必然性 ,分析了推行生态效益管理的关键和难点 ,并提出我国企业推行生态效益的对策建议。 相似文献
35.
环境影响评价有效性评估理论研究 总被引:7,自引:0,他引:7
结合系统工程理论,初步建立环境影响评价有效性评估的概念方法和理论体系,据此对我国环境影响评价有效性进行初步评估,并提出进一步提高我国环境影响评价有效性的对策及建议。 相似文献
36.
碎砖骨料再生混凝土配合比研究 总被引:1,自引:0,他引:1
用正交法试验分析了碎砖骨料混凝土的配合比,提出水灰比和碎砖骨料掺量分别是影响混凝土强度和流动性的主要因素。倡导用碎砖做混凝土骨料,保护生态环境。 相似文献
37.
The effects of land use and its patterns on soil properties in a small catchment of the Loess Plateau 总被引:3,自引:0,他引:3
Due to relatively strong human activities in the hilly area of Loess Plateau,the natural vegetation has been destroyed,and landscape pattern based on agricultural land matrix was land use mosaic composing of shrub land,grassland,woolland and orchard.This pattern has an important effect on soil moisture and soil nutrients.The Danangou catchment,a typical small catchment,was selected to study the effects of land use and its patterns on soil moisture and nutrients in this paper.The results are as follows:The comparisons of soil moisture among seven land uses for wet year and dry year were performed:(1)the average of soil moisture content for whole catchment was 12.11% in wet year,while it was 9.37% in dry year;(2)soil moisture among seven land uses was significantly different in dry year,but not in wet year;(3) form wet year to dry year,the profile type of soil moisture changed from decreasing type to fluctuation-type and from fluctuant type to increasing type;(4)the increasing trend in soil moisture from the top to foot of hillslope occurred in simple land use along slope,while complicated distribution of soil moisture was observed in multiple land uses along slope.The relationships between soil nutrients and land uses and landscape positions were analysed:(1)five nutrient contents of soil organic matter(SOM),total N(TN),available N(AN),total P(TP) and available P(AP) in hilly area were lower than that in other areas.SOM content was less than 1%,TN content less than 0.07%,and TP fallow land and cropland,and higher level in soil fertility was found in crop-fruit intercropping land among croplands;(3)soil nutrient distribution and responses to landscape positions were variable depending on slope and the location of land use types. 相似文献
38.
Axel Michaelowa John O’brien 《Mitigation and Adaptation Strategies for Global Change》2006,11(3):711-722
A United Nations Framework Convention on Climate Change (UNFCCC) Joint Implementation (JI) host country has to make sure that
JI projects are additional to avoid extra costs to generate the reductions necessary to cover the deduction of Emission Reduction
Units (ERUs) from the country’s Kyoto Protocol emissions budget. A tender of ERUs by the government allows to generate additional
reductions beyond the ERUs issued if it thoroughly checks project additionality. The government of New Zealand is running
a tender for JI projects under the title “Projects to Reduce Emissions” since 2003. In two rounds, 10 million ERUs have been
awarded and several projects have already entered into contracts with European buyers. The ratio of ERUs awarded to reductions
achieved was 0.8 in the second tender. However it remains to be seen whether the additionality test of this tender is sufficient
to exclude clearly non-additional projects. 相似文献
39.
通过对氧化沟工艺处理炼油污水效果的分析,提出影响处理效果的各种因素,并探讨对策及建议。 相似文献
40.