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151.
Different ranking methods: potentialities and pitfalls for the case of European opinion poll 总被引:1,自引:0,他引:1
Paola Annoni 《Environmental and Ecological Statistics》2007,14(4):453-471
Prioritization and ranking of objects are primary needs in various substantive fields. It might be said that ranking and comparison
are the first step in every risk assessment procedure, whatever the ‘risk’ is intended as: social, environmental, political
or economic. Often objects to be ranked are valued by a multi-dimensional attribute which is usually transformed into a composite
numerical score. In spite of conventional solutions, the author agrees with recent recommendations of performing multiple
ranking, keeping indicators separated. Different innovative methods are analyzed and compared: Hasse diagrams method, POSAC
and Nonlinear PCA. The first one stems directly from partial order theory, the second one may be seen as an approximation
of Hasse representation in a two dimensional space, whilst the third one belongs to the wide set of non-linear multivariate
techniques and it is particularly suitable in handling data of categorical type. Among them, the first two methods compare
objects on the basis only on order property of data, whilst the last one simultaneously performs an optimal scale of qualitative
attributes and a ranking of objects. The case study is based on the Eurobarometer survey carried out in 2002, at the request
of the European Commission, which collects Europeans opinion about various political and social issues. The analysis is focused
on users’ level of satisfaction about access easiness, cost, quality, information received and contracts of various services
of general interest, such as telephone services, power (gas and electricity) providers, water and postal utilities, urban
and rail transports. Separate indicators are set up for each facet of each service within different European regions. Eventually,
the ranking of European regions is performed on the basis of the overall performance of services of general interest, as perceived
by users. Selected methods lead to almost alike results, still with some differentiations due to different approaches used.
As it frequently occurs, each method has its own advantages and pitfalls which are here explored and compared. 相似文献
152.
Female mallard mating preferences for multiple male ornaments 总被引:3,自引:1,他引:3
K. E. Omland 《Behavioral ecology and sociobiology》1996,39(6):353-360
Mating preferences were studied in captive wild-stock female mallards. Independent observers scored ornament brightness for
the bill and eight plumage areas of male mallards on a scale of 1 to 6. Ornament scores were generally positively correlated
with each other as indicated by univariate correlations and principal component analysis. Males with higher bill scores were
significantly more likely to obtain pairings. None of eight individual plumage ornaments were significant predictors of pairing
success, but males with higher average plumage scores had significantly higher pairing success. Males that completed the molt
first were also significantly more likely to be paired. Thus females may have paid some attention to plumage brightness. Stepwise
multiple regression produced a model that included only bill and molt, both of which contributed a similar degree (r
2 = 0.39); plumage ornaments and size measurements did not enter the model. These results are interpreted in light of hypotheses
for the evolution of multiple ornaments, and phylogenetic plumage patterns in dabbling ducks.
Received: 18 December 1995 / Accepted after revision: 22 September 1996 相似文献
153.
It is widely acknowledged that a simplified and robust approach to evaluating thecombined effects of chemical mixtures is critical for ecological risk assessment (ERA) of contaminated soil. The earthworm (Eisenia fetida) was used as a model to study the combined effects of polymetallic contamination and the herbicide siduron in field soil using a microcosm experiment. The responses of multiple biomarkers, including the activities of catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and acetylcholine esterase (AChE), the concentrations of glycogen, soluble protein (SP), malonaldehyde (MDA), and metallothionein (MT), and the neutral red uptake test (NRU), were investigated. Multivariate analysis, Principal Component Analysis (PCA) and Spearman's Rank Correlations analysis (BVSTEP) revealed that the activities of AChE and CAT and the NRU content were the prognostic biomarkers capturing the minimum data set of all the variables. Internal Cd (tissue Cd) in earthworms was closely related to the health status of worms under combined contamination of heavy metals and siduron. The integrated effect (Emix) calculated based on the activities of AChE and CAT and NRU content using the stress index method had significantly linear regression with internal Cd (p<0.01). Emix(10), Emix(20), and Emix(50) were then calculated, at 1.27, 1.63 and 2.71 mg/kg dry weight, respectively. It could be concluded that a bioassay-based approach incorporating multivariate analysis and internal dose was pragmatic and applicable to evaluating combined effects of chemical mixtures in soils under the guidance of the top-down evaluation concept of combined toxicity. 相似文献
154.
Wetlands are critical natural resources in developing countries where they perform a range of environmental functions and provide numerous socio-economic benefits to local communities and a wider population. In recent years, however, many wetlands throughout eastern Africa have come under extreme pressure as government policies, socio-economic change and population pressure have stimulated a need for more agriculturally productive land. Although wetland drainage and cultivation can make a key contribution to food and livelihood security in the short term, in the long term there are concerns over the sustainability of this utilization and the maintenance of wetland benefits. This article draws upon recent research carried out in western Ethiopia, which addressed the sustainability of wetland agriculture in an area of increasing food insecurity and population pressure. It discusses the impacts of drainage and cultivation on wetland hydrology and draws attention to local wetland management strategies, particularly those characterized by multiple use of wetlands, where agriculture exists alongside other wetland uses. The article suggests that where multiple wetland uses exist, a range of benefits can be sustained with little evidence of environmental degradation. Ways of promoting and empowering such sustainable wetland management systems are discussed in the context of the wider need for water security throughout the region. 相似文献
155.
Resource inventory and monitoring (I&M) programs in national parks combine multiple objectives in order to create a plan of
action over a finite time horizon. Because all program activities are constrained by time and money, it is critical to plan
I&M activities that make the best use of available agency resources. However, multiple objectives complicate a relatively
straightforward allocation process. The analytic hierarchy process (AHP) offers a structure for multiobjective decision making
so that decision-makers’ preferences can be formally incorporated in seeking potential solutions. Within the AHP, inventory
and monitoring program objectives and decision criteria are organized into a hierarchy. Pairwise comparisons among decision
elements at any level of the hierarchy provide a ratio scale ranking of those elements. The resulting priority values for
all projects are used as each project’s contribution to the value of an overall I&M program. These priorities, along with
budget and personnel constraints, are formulated as a zero/one integer programming problem that can be solved to select those
projects that produce the best program. An extensive example illustrates how this approach is being applied to I&M projects
in national parks in the Pacific Northwest region of the United States. The proposed planning process provides an analytical
framework for multicriteria decisionmaking that is rational, consistent, explicit, and defensible. 相似文献
156.
江苏中部农业园小麦和土壤镉元素含量关系研究 总被引:1,自引:0,他引:1
为研究江苏中部农业园土壤和小麦镉元素含量[ω(Cdsoil)和ω(Cdwheat)]关系,采集了土壤和小麦样品40组,采用多元线性回归分析方法建立ω(Cdwheat)的预测模型。结果表明:(1)研究区表层土壤呈中性偏弱酸性,ω(Cdsoil)含量范围为0.083~0.239 mg/kg,平均值为0.152 mg/kg,均低于《土壤环境质量 农用地土壤污染风险管控标准(试行)》(GB 15618—2018)中农用地土壤污染风险筛选值,属于优先保护类土壤;(2)依据《食品安全国家标准 食品中污染物限量》(GB 2762—2017)中ω(Cdwheat)限定值(0.1 mg/kg),小麦籽实Cd超标率为10%;(3)ω(Cdwheat)主要受表层ω(Cdsoil)控制,同时受到土壤钼(Mo)、铅(Pb)、砷(As)、钙(Ca)和镉(Cd)等元素有效态影响,另外,还受土壤理化性质(pH值和有机质)的影响。 相似文献
157.
Josef Bryja Hana Patzenhauerová Tomáš Albrecht Ladislav Mošanský Michal Stanko Pavel Stopka 《Behavioral ecology and sociobiology》2008,63(2):251-260
Sexual selection in most vertebrates is based on the evolution of fitness optimization strategies such as multiple-male mating
(MMM). Several ecological correlates of MMM have been identified in bird and fish populations; however, only few studies have
documented the effects of environmental change on promiscuity in mammals. In this study, the 127 pregnant females from four
central European and ecologically diverse species of field mice (genus Apodemus) were studied to assess the role of ecological factors that may have shaped the evolution of particular mating systems. MMM
was found in all analyzed species: in Apodemus uralensis and Apodemus flavicollis, up to two males could be identified as the fathers of a particular litter, while three males sired 9.1% of analyzed litters
of Apodemus sylvaticus and 20.6% of Apodemus agrarius. Furthermore, there were obvious differences between species in relative testes size and the proportion of multiple sired
litters during those seasons when the opportunity for multiple mating was high. The species with the smallest testes and the
least promiscuous was A. uralensis (only 43.5% of multiple sired litters), while the species with the biggest testes and the most promiscuous was A. agrarius (69.2%). MMM was significantly associated with higher litter size in A. flavicollis, and the probability of MMM strongly increased with season in A. agrarius and with abundance in A. uralensis. These results indicate that ecological factors are associated with MMM rates in Apodemus field mice and more research is needed to fully understand the evolution of mating strategies at different levels of biological
resolution. 相似文献
158.
Many species base their choice of mates on multiple signals which provide them with different kinds of information. Choosers
may assess the signals together to evaluate the overall quality of potential mates, but individuals often pay attention to
different signals in different contexts. In Rhinogobius brunneus, a fish displaying exclusive male parental care, females generally prefer males showing larger first dorsal fins (FDF) and
more active courtship displays as mates. Females choosing a mate usually initially assess the FDF and later utilize courtship
for the final decision. In our experiments, females with different hunger states used different signals when selecting mates.
Females in both hunger states preferred males with larger FDF in the first stage. In the second stage, well-fed females showed
highly repeatable choice, whereas poorly fed females responded only to variation in the courtship activity of males. The males
preferred by poorly fed females exhibited significantly higher offspring survival than nonpreferred males. Under conditions
of food shortage, males allocate more energy to future reproduction at the expense of the present brood, and females may prioritize
signals predictive of offspring survivorship over signals reflecting other aspects in male quality to minimize the losses
in direct benefits. We conclude that R. brunneus females may employ information from both signals but dynamically adjust their prioritization of each signal to current conditions
to ensure the choice that is currently most adaptive. 相似文献
159.
Nadia Silva Jesús M. Avilés Etiénne Danchin Deseada Parejo 《Behavioral ecology and sociobiology》2008,62(12):1969-1979
Animals may assess the quality of other individuals by using information that different ornaments may provide. The European
Roller (Coracias garrulus) is a socially monogamous species in which males and females display highly conspicuous plumage colouration. According to
the mutual selection hypothesis, we predicted that, in this species, plumage coloration could signal individual quality in
both sexes because both female and male rollers invest a considerable amount of time caring for their offspring. We used spectrophotometric
measurements to investigate the information content of multiple plumage colour traits. We found that the roller is actually
a sexually dimorphic and dichromatic species. Different plumage colours from different origins were correlated within individual.
Head and back brightness correlated with body condition in both sexes, and in males, head brightness correlated with the number
of fledglings in successful nests, while head green-yellow saturation correlated with parental provisioning. Meanwhile, in
females, back brightness was related to the number of fledglings in successful nests and to parental provisioning rate. In
addition, there was a positive assortative mating in relation to weight, body condition, head green-yellow saturation and
back brightness. Finally, we found a positive correlation between parent and offspring coloration. Altogether, these results
suggest that multiple colour traits may act as quality indicators in the roller and that they may be used by the two sexes
to assess potential mate quality. 相似文献
160.
利用淮安市环境监测中心站1998年—2000年洪泽湖水质监测资料,以洪泽湖水体最能表征营养化状态进程的叶绿素a为基准因子,分析了洪泽湖水质富营养化的原因。通过QBASIC多元逐步回归分析,得出洪泽湖水质富营养化的主控因子是悬浮物、透明度,总磷是富营养化的潜在限制性营养盐。 相似文献