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111.
刘爽  张笑  赵文吉  李珊珊  江磊 《中国环境科学》2019,39(10):4270-4278
选择山地面积占98.5%的北京市门头沟区作为研究区,利用资源三号(ZY-3)三线阵前、后视影像构建立体模型,提取数字高程模型(Digital Elevation Model,DEM).由高分二号影像,基于CART(Classification and Regression Tree)决策树的面向对象方法对居住房屋进行提取,获取空间分布与面积,并结合采暖面积、采暖季燃煤量等抽样调研数据确定的深、浅山区(海拔>300m为深山区,海拔<300m为浅山区)燃煤系数,建立燃煤量估算模型.进一步,基于文献调研法获取型煤排放因子,测算燃煤产生的PM10、PM2.5、NOx、SO2、CO的排放量.结果表明:借助遥感技术,基于DEM可对山区燃煤污染物排放量进行快速有效测算.地形对冬季燃煤量有显著影响,深山区燃煤系数分别为12.5kg/m2,浅山区为9.375kg/m2.2017年门头沟使用型煤取暖的房屋面积为5.68km2,冬季燃煤总量为6.52万t,山区各镇大气污染物排放量差别较大.  相似文献   
112.
本文对冲击台在冲击试验前,因测试冲击波形是否符合试验要求而所做的过多模拟测试,会导致试验效率较低、试验材料浪费等问题,在数据试验的基础上,运用泰勒公式和最小二乘法,将复杂的物理模型转化为若干个简单的数学模型,给出了一种冲击台的波形发生器的模拟选定和冲击台提升高度的确定方法,以确定冲击波形。测试数据表明,该方法建立的冲击波形的确定方法是可靠的。  相似文献   
113.
Genetic diversity within species represents a fundamental yet underappreciated level of biodiversity. Because genetic diversity can indicate species resilience to changing climate, its measurement is relevant to many national and global conservation policy targets. Many studies produce large amounts of genome-scale genetic diversity data for wild populations, but most (87%) do not include the associated spatial and temporal metadata necessary for them to be reused in monitoring programs or for acknowledging the sovereignty of nations or Indigenous peoples. We undertook a distributed datathon to quantify the availability of these missing metadata and to test the hypothesis that their availability decays with time. We also worked to remediate missing metadata by extracting them from associated published papers, online repositories, and direct communication with authors. Starting with 848 candidate genomic data sets (reduced representation and whole genome) from the International Nucleotide Sequence Database Collaboration, we determined that 561 contained mostly samples from wild populations. We successfully restored spatiotemporal metadata for 78% of these 561 data sets (n = 440 data sets with data on 45,105 individuals from 762 species in 17 phyla). Examining papers and online repositories was much more fruitful than contacting 351 authors, who replied to our email requests 45% of the time. Overall, 23% of our email queries to authors unearthed useful metadata. The probability of retrieving spatiotemporal metadata declined significantly as age of the data set increased. There was a 13.5% yearly decrease in metadata associated with published papers or online repositories and up to a 22% yearly decrease in metadata that were only available from authors. This rapid decay in metadata availability, mirrored in studies of other types of biological data, should motivate swift updates to data-sharing policies and researcher practices to ensure that the valuable context provided by metadata is not lost to conservation science forever.  相似文献   
114.
苏里格气田地处毛乌素沙漠,是典型的低渗、低压、低丰度岩性气藏,单井产量低,建井数量多,靠人工管理的难度大,本着降本增效、减少风险的原则,数字化集气站在苏里格气田得到了大力推广,其应用过程中面临着与传统集气站不同的安全风险。文章对数字化集气站运行过程中的各类安全风险进行了分析,介绍了风险应对的控制措施,期望为数字化集气站的安全管理提供新的思路。  相似文献   
115.
为提高尾矿库这一矿山重大危险源安全监管系统化水平,实现数字化安全监管,提出了全寿命周期DADT循环管控技术理论。这项技术首先需要整合管控对象的三维数字化测控成果与调研资料,建立全寿命周期“健康档案”,其次运用DADT循环管控方法,同时耦合相关专业技术,“诊断、分析、设计、治理”管控对象的安全特征要素,发现并解决安全隐患。结合尾矿库自身特点与测控成果,阐述了尾矿库全寿命周期DADT循环管控技术的运行流程。以白马尾矿库为例,在三维点云数据基础上建立实体模型,运用全寿命周期DADT循环管控技术,耦合调洪演算过程,结果表明,尾矿库在后期堆排过程中,库区会出现“封闭水域”,提前发现并科学解决了尾矿库排洪隐患。全寿命周期DADT循环管控技术的运用,克服了以往安全监管对管控对象安全状况系统性掌控的不足,有利于精确处理安全隐患,为数字化安全监管的实现提供了一种全新思路。  相似文献   
116.
Ongoing loss of biological diversity is primarily the result of unsustainable human behavior. Thus, the long-term success of biodiversity conservation depends on a thorough understanding of human–nature interactions. Such interactions are ubiquitous but vary greatly in time and space and are difficult to monitor efficiently at large spatial scales. However, the Information Age also provides new opportunities to better understand human–nature interactions because many aspects of daily life are recorded in a variety of digital formats. The emerging field of conservation culturomics aims to take advantage of digital data sources and methods to study human–nature interactions and thus to provide new tools for studying conservation at relevant temporal and spatial scales. Nevertheless, technical challenges associated with the identification, access, and analysis of relevant data hamper the wider adoption of culturomics methods. To help overcome these barriers, we propose a conservation culturomics research framework that addresses data acquisition, analysis, and inherent biases. The main sources of culturomic data include web pages, social media, and other digital platforms from which metrics of content and engagement can be obtained. Obtaining raw data from these platforms is usually desirable but requires careful consideration of how to access, store, and prepare the data for analysis. Methods for data analysis include network approaches to explore connections between topics, time-series analysis for temporal data, and spatial modeling to highlight spatial patterns. Outstanding challenges associated with culturomics research include issues of interdisciplinarity, ethics, data biases, and validation. The practical guidance we offer will help conservation researchers and practitioners identify and obtain the necessary data and carry out appropriate analyses for their specific questions, thus facilitating the wider adoption of culturomics approaches for conservation applications.  相似文献   
117.
基于XML语言的信息隐藏方法   总被引:5,自引:2,他引:5  
XML作为网络中的信息交换格式,一出现便得到了广泛的应用和支持。XML不是一种普通的文本语言,它用于置标电子文档,是一种使其数据具有结构化的置标语言。利用XML的这一特性,可以将秘密的信息隐藏到XML文本中。笔者通过研究XML语言的基本特性和XML语言在网络中的应用,提出了几种基于XML语言的信息隐藏方法,这种方法的理论基础简单,同时也便于在实际中应用。  相似文献   
118.
The separation of the base flow component from a varying streamflow hydrograph is called “hydrograph analysis.” In this study, two digital filter based separation modules, the BFLOW and Eckhardt filters, were incorporated into the Web based Hydrograph Analysis Tool (WHAT) system. A statistical component was also developed to provide fundamental information for flow frequency analysis and time series analysis. The Web Geographic Information System (GIS) version of the WHAT system accesses and uses U.S. Geological Survey (USGS) daily streamflow data from the USGS web server. The results from the Eckhardt filter method were compared with the results from the BFLOW filter method that was previously validated, since measured base flow data were not available for this study. Following validation, the two digital filter methods in the WHAT system were run for 50 Indiana gaging stations. The Nash‐Sutcliffe coefficient values comparing the results of the two digital filter methods were over 0.91 for all 50 gaging stations, suggesting the filtered base flow using the Eckhardt filter method will typically match measured base flow. Manual separation of base flow from streamflow can lead to inconsistency in the results, while the WHAT system provides consistent results in less than a minute. Although base flow separation algorithms in the WHAT system cannot consider reservoir release and snowmelt that can affect stream hydrographs, the Web based WHAT system provides an efficient tool for hydrologic model calibration and validation. The base flow information from the WHAT system can also play an important role for sustainable ground water and surface water exploitation, including irrigation and industrial uses, and estimation of pollutant loading from both base flow and direct runoff. Thus, best management practices can be appropriately applied to reduce and intercept pollutant leaching if base flow contributes significant amounts of pollutants to the stream. This Web GIS based system also demonstrates how remote, distributed resources can be shared through the Internet using Web programming.  相似文献   
119.
江苏省常熟数字化遥测台网的建设在进入考核运行期间成功地记录了南黄海6.1级地震,取得了完整的数字地震波形记录。为深入进行地震动力学的研究提供了宝贵的资料  相似文献   
120.
ABSTRACT: A grid cell geographic information system (GIS) is used to parameterize SPUR, a quasi-physically based surface runoff model in which a watershed is configured as a set of stream segments and contributing areas. GIS analysis techniques produce various watershed configurations by progressive simplification of a stream network delineated from digital elevation models (DEM). We used three watershed configurations: ≥ 2nd, ≥ 4th, and ≥ 13th Shreve order networks, where the watershed contains 28, 15, and 1 channel segments with 66, 37, and 3 contributing areas, respectively. Watershed configuration controls simulated daily and monthly sums of runoff volumes. For the climatic and topographic setting in southeastern Arizona the ≥ 4th order configuration of the stream network and contributing areas produces results that are typically as good as the ≥ 2nd order network. However both are consistently better than the ≥ 13th order configuration. Due to the degree of parameterization in SPUR, model simulations cannot be significantly improved by increasing watershed configuration beyond the ≥ 4th order network. However, a range of Soil Conservation Service curve numbers derived from rainfall/runoff data can affect model simulations. Higher curve numbers yield better results for the ≥ 2nd order network while lower curve numbers yield better results for the ≥ 4th order network.  相似文献   
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