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731.
采用分子生物学的方法(定性/定量PCR、克隆文库)对洞庭湖岸边带沉积物中氨氧化古菌(Ammonia-Oxidizing Archaea,AOA)进行分子水平的多样性和丰度分析,并结合硝化速率潜势(Potential Nitrification Rate,PNR)剖析AOA在洞庭湖岸边带沉积物中氨氧化的作用.采用实时荧光定量PCR技术对氨氧化古菌AOA和氨氧化细菌(Ammonia-Oxidizing Bacteria,AOB)进行靶向amoA基因(氨氧化关键功能基因)的定量分析,发现古菌amoA基因的丰度为1.49×107 ~ 1.97×10s copies· g-1(以干土计),高于细菌amoA基因丰度(1.52×104 ~2.45×106copies·g-1,以干土计)1~4个数量级.洞庭湖岸边带沉积物硝化速率潜势为1.11 ~6.47 nmol·g-1·h-1(以N计),比细胞硝化速率为0.55 ~1.68 fmol· cell-1·d-1(以NH3计).硝化速率潜势与古菌amoA基因丰度之间呈现正向变化趋势,而与细菌amoA基因丰度呈负向变化趋势,指示了低氨氮环境下AOA在氨氧化过程中的主导作用.生物多样性分析表明,经酶切分型后得到的22个古菌amoA基因序列以97%的相似度划分为8个独立操作单元(Operational Taxonomic Unit,OTU).系统发育分析显示,OTU 1~6(14个序列)属于第一分支,OTU 7~8(8个序列)属于第二分支,且均属于一个新命名的古菌类群——奇古菌门(Thaumarchaeota).  相似文献   
732.
植物多酚改性膨润土吸附重金属镉实验研究   总被引:1,自引:0,他引:1  
对钙基膨润土、酸活化膨润土、自制单宁酸改性膨润土,通过表征测试研究了膨润土改性后的形态结构变化。结果表明:单宁酸改性膨润土较钙基膨润土结构未发生较大变化;并分别探讨了不同投加量、反应pH及不同初始浓度对单宁酸改性膨润土吸附镉的影响。实验表明:单宁酸改性膨润土对Cd2+的吸附性能优于钙基膨润土及酸活化膨润土,在材料用量越小及反应pH越低时,单宁酸对膨润土吸附Cd2+的促进作用越明显。单宁酸改性膨润土对Cd2+的吸附能用Langmuir吸附方程进行描述,其最大吸附量约为31.25mg/g,比钙基膨润土提高了20.6%。本研究将为非金属矿物在水体及土壤重金属污染修复方面的应用提供理论基础和科学依据。  相似文献   
733.
近年来,随着国家对煤炭行业控制环境污染的条件越来越严格,为了更有效的治理煤场环境污染,改善煤场周边地区环境质量,根据国内已建成的大型封闭厂房的设计经验,提出一种封闭式煤炭风选车间,车间采用轻型门式钢架结构设计,常规经济柱距6m,抗风柱柱距7.5m,室内净高10m。工程长度90m,跨度35m,屋盖系统采用钢桁架结构体系,单层压型彩色钢板封闭。封闭车间同时配套通风除尘系统,有效降低煤尘量。  相似文献   
734.
Freshwater ecosystems provide irreplaceable services for both nature and society. The quality and quantity of freshwater affect biogeochemical processes and ecological dynamics that determine biodiversity, ecosystem productivity, and human health and welfare at local, regional and global scales. Freshwater ecosystems and their associated riparian habitats are amongst the most biologically diverse on Earth, and have inestimable economic, health, cultural, scientific and educational values. Yet human impacts to lakes, rivers, streams, wetlands and groundwater are dramatically reducing biodiversity and robbing critical natural resources and services from current and future generations. Freshwater biodiversity is declining rapidly on every continent and in every major river basin on Earth, and this degradation is occurring more rapidly than in terrestrial ecosystems. Currently, about one third of all global freshwater discharges pass through human agricultural, industrial or urban infrastructure. About one fifth of the Earth’s arable land is now already equipped for irrigation, including all the most productive lands, and this proportion is projected to surpass one third by midcentury to feed the rapidly expanding populations of humans and commensal species, especially poultry and ruminant livestock. Less than one fifth of the world’s preindustrial freshwater wetlands remain, and this proportion is projected to decline to under one tenth by midcentury, with imminent threats from water transfer megaprojects in Brazil and India, and coastal wetland drainage megaprojects in China. The Living Planet Index for freshwater vertebrate populations has declined to just one third that of 1970, and is projected to sink below one fifth by midcentury. A linear model of global economic expansion yields the chilling prediction that human utilization of critical freshwater resources will approach one half of the Earth’s total capacity by midcentury. Although the magnitude and growth of the human freshwater footprint are greater than is generally understood by policy makers, the news media, or the general public, slowing and reversing dramatic losses of freshwater species and ecosystems is still possible. We recommend a set of urgent policy actions that promote clean water, conserve watershed services, and restore freshwater ecosystems and their vital services. Effective management of freshwater resources and ecosystems must be ranked amongst humanity’s highest priorities.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01318-8) contains supplementary material, which is available to authorized users.  相似文献   
735.
Conservation technology holds the potential to vastly increase conservationists’ ability to understand and address critical environmental challenges, but systemic constraints appear to hamper its development and adoption. Understanding of these constraints and opportunities for advancement remains limited. We conducted a global online survey of 248 conservation technology users and developers to identify perceptions of existing tools’ current performance and potential impact, user and developer constraints, and key opportunities for growth. We also conducted focus groups with 45 leading experts to triangulate findings. The technologies with the highest perceived potential were machine learning and computer vision, eDNA and genomics, and networked sensors. A total of 95%, 94%, and 92% respondents, respectively, rated them as very helpful or game changers. The most pressing challenges affecting the field as a whole were competition for limited funding, duplication of efforts, and inadequate capacity building. A total of 76%, 67%, and 55% respondents, respectively, identified these as primary concerns. The key opportunities for growth identified in focus groups were increasing collaboration and information sharing, improving the interoperability of tools, and enhancing capacity for data analyses at scale. Some constraints appeared to disproportionately affect marginalized groups. Respondents in countries with developing economies were more likely to report being constrained by upfront costs, maintenance costs, and development funding (p = 0.048, odds ratio [OR] = 2.78; p = 0.005, OR = 4.23; p = 0.024, OR = 4.26), and female respondents were more likely to report being constrained by development funding and perceived technical skills (p = 0.027, OR = 3.98; p = 0.048, OR = 2.33). To our knowledge, this is the first attempt to formally capture the perspectives and needs of the global conservation technology community, providing foundational data that can serve as a benchmark to measure progress. We see tremendous potential for this community to further the vision they define, in which collaboration trumps competition; solutions are open, accessible, and interoperable; and user-friendly processing tools empower the rapid translation of data into conservation action. Article impact statement: Addressing financing, coordination, and capacity-building constraints is critical to the development and adoption of conservation technology.  相似文献   
736.
Abstract:  Rapid biodiversity assessment and conservation planning require the use of easily quantified and estimated surrogates for biodiversity. Using data sets from Québec and Queensland, we applied four methods to assess the extent to which environmental surrogates can represent biodiversity components: (1) surrogacy graphs; (2) marginal representation plots; (3) Hamming distance function; and (4) Syrjala statistical test for spatial congruence. For Québec we used 719 faunal and floral species as biodiversity components, and for Queensland we used 2348 plant species. We used four climatic parameter types (annual mean temperature, minimum temperature during the coldest quarter, maximum temperature during the hottest quarter, and annual precipitation), along with slope, elevation, aspect, and soil types, as environmental surrogates. To study the effect of scale, we analyzed the data at seven spatial scales ranging from 0.01° to 0.10° longitude and latitude. At targeted representations of 10% for environmental surrogates and biodiversity components, all four methods indicated that using a full set of environmental surrogates systematically provided better results than selecting areas at random, usually ensuring that ≥90% of the biodiversity components achieved the 10% targets at scales coarser than 0.02°. The performance of surrogates improved with coarser spatial resolutions. Thus, environmental surrogate sets are useful tools for biodiversity conservation planning. A recommended protocol for the use of such surrogates consists of randomly selecting a set of areas for which distributional data are available, identifying an optimal surrogate set based on these areas, and subsequently prioritizing places for conservation based on the optimal surrogate set.  相似文献   
737.
738.
Latin America comprehends notable variations in terms of natural environment, availability of natural resources, living standards, and demographic patterns. Latin America is a mosaic of cultures, post- and pre-Columbian. The rich variety of life forms discovered and described by chroniclers and traveling naturalists in the Neotropics contributed to the proposal, in mid-XVIIIth century, of a new system of classification and a scientific code of nomenclature for all organisms. Biodiversity was, for many centuries, a source of resources to be exploited in natura. In scientific circles, its inventory became the domain of taxonomists. But modern technology showed how important the miriad of life forms really are as sources of chemical molecules to be engineered as drugs and reassembled as novel manufactured products. We are on the brink of a new agricultural and medical revolution, thanks to the techniques of genetic engineering, which will lead eventually to the elimination of hunger and malnutrition.In this essay, the Brazilian environmental and social heterogeneity will serve as an example to illustrate some key points, which have influenced sustainability policies. The Amazon deforestation and indigenous knowledge (IK), subjects often associated with areas of high biodiversity, are usually the focus of environmental debates. The importance of IK in integrating development, reducing poverty and sustainability are considered together with the intellectual property rights of native populations.In the World Summit on Sustainable Development (WSSD) Implementation Plan, a few paragraphs were dedicated to Latin America, because of the pre-existing Action Platform on the Road to Johannesburg 2002, approved in Rio de Janeiro in October 2001. This paper calls attention to the need to draw up specific environmental policies for a region which shows an extremely high cultural and biological diversity, associated with a high availability of forests and water, among other resources.  相似文献   
739.
Slovene agriculture is going throughdrastic changes. Most of the land is stillowned by small farmers. The production isoriented to the market and is based on modernWestern technology. It is associated withincreasing pollution and is becoming a seriousthreat to biodiversity. Many of the wild plantsare endangered due to genetic erosion withinspecies. The traditional crops and varietiesare being replaced by imported materials andthe use of chemicals has been increasing. Manyof the traditional varieties have beenneglected and/or lost. The existing germplasmcollections are incomplete and frequently donot include traditional varieties. There areonly a few breeding organizations with limitedcapacities and collections. The legislation isnot efficient enough to protect the environmentand biotic diversity. Schools, media,religious, sport, tourist, and otherorganizations should be more active inpromoting the respect for biodiversity.  相似文献   
740.
Habitat destruction is among the greatest threats facing biodiversity, and it affects common and threatened species alike. However, metrics for communicating its impacts typically overlook the nonthreatened component of assemblages. This risks the loss of habitat going unreported for species that comprise the majority of assemblages. We adapted a widely used measure for summarizing researcher output (the h index) to provide a metric that describes natural habitat loss for entire assemblages, inclusive of threatened and nonthreatened species. For each of 447 Australian native terrestrial bird species, we combined information on their association with broad vegetation groups with distributional range maps to identify the difference between the estimated pre-European and current extents of potential habitat, defined as vegetation groups most closely associated with each species. From this, we calculated the loss index (LI), which revealed that 30% of native birds have each lost at least 30% of their potential natural habitat (LI = 30). At the subcontinental scale, LIs ranged from 15 in arid Australia to 61 in the highly transformed southeastern part of the country. Different subcomponents of the assemblage had different LI values. For example, Australia's parrots (n = 52 species) had an LI of 38, whereas raptors (n = 32 species) had an LI of 25. The LI is simple to calculate and can be determined using readily available spatial information on species distributions, native vegetation associations, and human impacts on natural land cover. This metric, including the curves used to deduce it, could complement other biodiversity indices if it is used for regional and global biodiversity assessments that compare the status of natural habitat extent for assemblages within and among nations, monitor changes through time, and forecast future changes to guide strategic land-use planning. The LI is an intuitive tool that can be used to summarize and communicate how human actions affect whole assemblages, not just threatened species.  相似文献   
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