全文获取类型
收费全文 | 1514篇 |
免费 | 50篇 |
国内免费 | 75篇 |
专业分类
安全科学 | 142篇 |
废物处理 | 6篇 |
环保管理 | 318篇 |
综合类 | 510篇 |
基础理论 | 143篇 |
环境理论 | 1篇 |
污染及防治 | 40篇 |
评价与监测 | 137篇 |
社会与环境 | 137篇 |
灾害及防治 | 205篇 |
出版年
2024年 | 2篇 |
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 12篇 |
2020年 | 17篇 |
2019年 | 9篇 |
2018年 | 19篇 |
2017年 | 39篇 |
2016年 | 38篇 |
2015年 | 38篇 |
2014年 | 38篇 |
2013年 | 68篇 |
2012年 | 69篇 |
2011年 | 105篇 |
2010年 | 99篇 |
2009年 | 118篇 |
2008年 | 95篇 |
2007年 | 144篇 |
2006年 | 111篇 |
2005年 | 112篇 |
2004年 | 87篇 |
2003年 | 89篇 |
2002年 | 71篇 |
2001年 | 51篇 |
2000年 | 47篇 |
1999年 | 36篇 |
1998年 | 35篇 |
1997年 | 25篇 |
1996年 | 13篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 8篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1989年 | 1篇 |
排序方式: 共有1639条查询结果,搜索用时 593 毫秒
11.
研究地理信息系统(GIS)技术在环境综合治理中的应用,基于ArcViewGIS探讨实现GIS热链接的方法,通过Avenue语言编写程序进行ArcView的二次开发,同时建立文本、图像热链接,克服系统只能实现单一对象热连接的不便.建立环境治理区城图像数据库、基础信息数据库,应用地理信息系统技术实现环境治理工程规划设计、检查验收的可视化.通过ArcViewGIS的热链接功能提供准确的、可视化的环境综合治理依据. 相似文献
12.
13.
A Simulation of Temporal and Spatial Variations in Carbon at Landscape Level: A Case Study for Lake Abitibi Model Forest in Ontario,Canada 总被引:2,自引:0,他引:2
Xiaolu Zhou Changhui Peng Qing-Lai Dang Jiaxin Chen Sue Parton 《Mitigation and Adaptation Strategies for Global Change》2007,12(4):525-543
Using a case study of the Lake Abitibi Model Forest (LAMF), this study aims to assess the temporal and spatial variability
in carbon storage during 1990–2000, and to present a comprehensive estimation of the carbon budget for LAMF's ecosystems.
As well, it provided the information needed by local forest managers to develop ecological and carbon-based indicators and
monitor the sustainability of forest ecosystems. Temporal and spatial carbon dynamics were simulated at the landscape level
using ecosystem model TRIPLEX1.0 and Geographical Information System (GIS). The simulated net primary productivity (NPP) and
carbon storage in forest biomass and soil were compared with field data and results from other studies for Canada's boreal
forests. The results show that simulated NPP ranged from 3.26 to 3.34 tC ha−1 yr−1 in the 1990s and was consistent with the range measured during the Boreal Ecosystem-Atmosphere Studies (BOREAS) in central
Canada. Modeled NPP was also compared with the estimation from remote sensing data. The density of total above-and belowground
biomass was 125.3, 111.8, and 106.5 tC ha−1 for black spruce, trembling aspen, and jack pine in the LAMF ecosystem, respectively. The total carbon density of forested
land was estimated at 154.4 tC ha−1 with the proportion of 4:6 for total biomass and soil. The analysis of net carbon balance of ecosystem suggested that the
LAMF forest ecosystem was acting as a carbon sink with an allowable harvest in the 1990s. 相似文献
14.
基于GIS的煤矿生产安全管理系统 总被引:8,自引:0,他引:8
煤矿生产安全管理系统本着服务矿山、建设数字化矿山的原则,目的是实现矿山安全信息的收集、管理、可视化分析,针对不同的管理层人员的需求提供相关服务,给决策者提供安全策略。利用地理信息系统(GIS)的数据显示、分析能力.并结合网络化的数据库管理系统(DBMS)能很好地实现矿山安全管理系统的各种功能。例如:安全人员人工检测或自动监测仪器检测的数据,经过系统处理后在地图上相关区域标示安全等级和基本安全情况,通过系统的近似分析优化生产区避难所的选址、设置应急路线等。 相似文献
15.
16.
17.
本文介绍了采用地理信息系统技术制作海洋环境质量评价图的基本内容,重点阐述了图件的表现形式、编制过程和具体的操作方法,为海洋环境质量评价图的制作提供了一种新的方法。 相似文献
18.
Baisen Zhang Ian Valentine Peter D. Kemp 《Agriculture, ecosystems & environment》2005,110(3-4):279-288
Decision tree, one of the data mining approaches, was used to model the relative abundance of five functional groups of plant species, namely high fertility response grasses (HFRG), low fertility tolerance grasses (LFTG), legume, moss and flatweeds in a New Zealand hill-pasture ecosystem using aboveground biomass. The model outputs were integrated with a geographic information system (GIS) to map and validate the predictions on a pasture. The decision tree models clearly revealed the interactions between the functional groups and environmental and management factors, and also indicated the relative importance of these factors in influencing the functional group abundance. Soil Olsen P was the most significant factor influencing the abundance of LFTG and moss, while soil bulk density, slope and annual P fertiliser input were the most significant factors influencing the abundance of legume, HFRG and flatweeds, respectively. Generally, slope and soil Olsen P were the two key factors underlying the patterns of abundance for these five functional groups. For the five functional groups studied, there was an overall predictive accuracy of 75%. Modelling functional group abundance simplified the investigation of the complex interrelationship between species and environment in a pasture ecosystem. The integration of the decision tree with GIS in this study provides a platform to investigate community structure and functional composition for a pasture over space, and thus can be applied as a tool in pasture management. 相似文献
19.
20.