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排序方式: 共有262条查询结果,搜索用时 0 毫秒
101.
本研究通过聚偏氟乙烯(PVDF)膜内负载具有协同吸附和催化作用的金属有机骨架(MOFs),吸附去除水中药品及个人护理品(PPCPs),并且达到膜滤过程中多功能材料吸附能力再生和膜污染控制的双重目的.在膜吸附方面,共混基质膜(MMMs)内MOFs材料UiO-66@Fe3O4@UiO-66能够有效吸附以水杨酸(SA)和邻-苯二甲酸二甲酯(DMP)为模板化合物的两种常见PPCPs.在膜催化再生方面,UiO-66@Fe3O4@UiO-66中的Fe3O4能够催化H2O2生成强氧化性的羟基自由基(HO·),实现对MOFs/PVDF膜吸附能力再生和膜内污染控制的耦合.结果表明,pH=7±0.1条件下,10%MOFs/PVDF膜对0.1 mmol·L-1SA和DMP吸附去除率最高,它们的去除率可分别达到64.2%和46.1%.除此之外,膜内UiO-66@Fe3O4... 相似文献
102.
药物和个人护理用品(PPCPs)采用传统的污水处理方法不易去除,高铁酸盐(Fe(VI))因具有强氧化性,且氧化产物Fe(III)具有絮凝作用,近年来被广泛应用于去除PPCPs。介绍了Fe(VI)近年来的制备进展,分析了Fe(VI)去除PPCPs的效率及影响因素,探讨了Fe(VI)与PPCPs的反应机理及产物、中间产物的毒性变化,并展望了未来Fe(VI)去除PPCPs的研究方向。Fe(VI)能有效去除多种PPCPs,去除效率受p H值、温度、Fe(VI)初始浓度和PPCPs性质影响,Fe(VI)与PPCPs反应的中间产物毒性值得关注。 相似文献
103.
Kai Lindström 《Behavioral ecology and sociobiology》1998,42(2):101-106
This study tested experimentally whether clutch size and the cost of care affect filial cannibalism in the sand goby, Pomatoschistus minutus. Evolutionary models of filial cannibalism suggest that egg eating has evolved as a way for the male parent to prolong his
breeding season. These models assume that eggs function as an alternative energy source for the constrained parent. I manipulated
clutch size by allowing males to mate with either one or two females, representing a small and a large clutch, respectively.
The addition of a small male shore crab, a common egg predator, increased the cost of care. I quantified fat reserves as a
measure of the condition of guarding males. Males who did not build nests had lower fat reserves than males who built nests,
suggesting that males with low energy reserves do not start breeding. Males with small clutches lost their nest to the crab
more often than males with large clutches. Neither filial cannibalism nor the amount of eggs eaten were affected by the treatments.
Males who consumed eggs had a higher fat percentage than males who did not eat eggs. The result that males with small clutches
lost their nests to the crabs supports the idea that eggs are defended only if the benefit from continued care will outweigh
the cost and that males therefore are sensitive to the trade-off between present and future reproductive success.
Received: 15 May 1997 / Accepted after revision: 15 November 1997 相似文献
104.
个人护理品(PCPs)作为一类新型污染物,具有微生物和藻类毒性,以及内分泌干扰效应,其主要通过人们的日常洗漱排入环境水体.本文建立了高效液相色谱-串联质谱测定水中19种PCPs的方法,样品以HLB固相萃取小柱净化,以甲醇和5 mmol·L-1乙酸铵为负模式测定流动相,甲醇和0.05%甲酸为正模式流动相,经Poroshell 120 EC-C18色谱柱分离后进行三重四极杆串联质谱多反应监测模式分析,内标法定量.各目标物的检出限为0.11-10.8 ng·L-1,定量限为0.37-36.0 ng·L-1,RSD为1.0%-13.6%,回收率为71.3%-137.9%.应用该方法对湘江水中PCPs的分布状况进行了初步调查,发现PCPs广泛存在于湘江水体中,68%的目标物得到了检出,浓度为ND-92.7 ng·L-1. 相似文献
105.
Testosterone and the allocation of reproductive effort in male house finches (Carpodacus mexicanus) 总被引:8,自引:1,他引:8
Testosterone has been proposed to serve as the mediator that controls the relative effort that an individual male bird will
devote to mating effort versus parental effort. Here, we demonstrate a testosterone-influenced trade-off between parental
and mating efforts in male house finches. Male house finches with experimentally elevated testosterone fed nestlings at a
significantly lower rate, but sang at a higher rate than males without manipulated testosterone levels. Females mated to testosterone-implanted
males fed nestlings at a significantly higher rate than females mated to males without testosterone implants, resulting in
similar feeding rates for both treated and untreated pairs. The effects of testosterone on male house finches, however, were
not as dramatic as the effects of testosterone observed in some other socially monogamous species of birds. Because extra-pair
copulations are uncommon in house finches and males provide substantial amounts of parental care, these more modest effects
may be due to differences in how the allocation of reproductive effort affects the costs and benefits of different reproductive
behaviors.
Received: 6 June 2000 / Accepted: 17 July 2000 相似文献
106.
Behavioural research on domestic pigs has included parent–offspring conflict, sibling competition, and the use of signals
which influence resource allocation. In this paper, we review key sow–piglet behavioural studies and discuss their relevance
to resource allocation theory. Sibling competition begins in the uterus and continues after birth, as piglets compete directly
for access to the sow’s teats. This competition is made more severe by a unique dentition, which newborn piglets use to lacerate
the faces of siblings during teat disputes. Competition often leads to the death of some littermates, especially those of
low birth weight. Piglets also compete indirectly for milk, apparently by stimulating milk production at the teats that they
habitually use at the expense of milk production by other teats. The complex nursing behavior of the sow appears designed
to prevent the more vigorous piglets from monopolizing the milk. Sows give vocal signals which both attract piglets to suckle
and synchronize their behavior during nursing episodes. Piglets give loud vocal signals when separated from the sow; calls
which vary in intensity and appear to be honest signals of need. Udder massage by piglets may also serve as an honest signal
of need. Parent–offspring conflict has been demonstrated experimentally in pigs. Specifically, when given the opportunity
to control contact with their piglets, sows nurse less frequently, provide less milk, and lose less weight during lactation
than sows that cannot control their level of contact. Because of this interesting natural history and because they are so
amenable to experimentation, domestic pigs provide a rich system for testing ideas drawn from resource allocation theory.
This contribution is part of the special issue “Sibling competition and cooperation in mammals” (guest editors: Robyn Hudson
and Fritz Trillmich). 相似文献
107.
Studies of parental behavior in various habitats provide an opportunity to gain insight into how different environments may
mold strategies of parental care. Brood division by parents has been hypothesized to occur facultatively within and among
species. Brood division occurs when each parent cares for specific offspring within a brood. We studied brood division in
a neotropical passerine, the western slaty antshrike (Thamnophilus atrinucha). Our results present a unique picture of a highly specialized example of avian brood division. Division was a fixed behavioral
pattern in the population studied: all broods divided by fledging and remained divided during the entire post-fledging period.
Brood division before fledging, a previously unreported phenomenon, occurred in 40% of nests observed. Parents that preferentially
fed a certain offspring (defined as their focal offspring) in the nest fed the same individual after fledging. Each parent
fed only its focal offspring in broods of one and two. The male parent cared for the heavier offspring and the first offspring
to leave the nest. Siblings were segregated spatially during the time of highest predation risk. These observations suggest
that a consistently high risk of predation on offspring has favored initial spatial segregation and inflexibility of brood
division behavior in this species. Factors other than predation risk alone may explain the observed patterns of long-term,
perfect brood division. Because high predation is common and relatively predictable in the tropics, selection for fixed brood
division may be stronger in tropical birds than in the temperate zone. 相似文献
108.
A. Manica 《Behavioral ecology and sociobiology》2002,51(4):319-323
Brood cycling, the alternation of periods of courtship and mating activity ("mating phase") with days of full brood care
("parental phase"), and total filial cannibalism, the consumption of all current offspring by a parent, have been interpreted
as a response to the conflicting demands faced by parental males during the breeding season. Under the assumption that these
two behaviours result from trade-offs among mating, caring and feeding, the strategy adopted by the male should depend on
egg number and age. This hypothesis was tested in the scissors-tail sergeant (Abudefduf sexfasciatus), a common tropical damselfish. Observations of undisturbed males and a brood reduction experiment confirmed all theoretical
predictions. The shift from the mating to parental phase occurred when an appropriate number of eggs had been obtained. When
the brood was reduced on the first day of the parental phase, males often reverted to the mating phase, but never did so if
the manipulation occurred on the second or third day. Only broods that were smaller than average were consumed by the parental
male. Artificial reduction of the brood increased the incidence of total filial cannibalism, but the probability of cannibalism
decreased with brood age.
Electronic Publication 相似文献
109.
药品及个人护理用品(pharmaceutical and personal care products,PPCPs)在污水中广泛检出,低浓度的PPCPs即可对生态环境和人体健康产生不利影响,污水处理厂出水排放是水环境PPCPs的重要源。活性污泥和生物膜工艺是目前最常用的污水生物处理工艺,这两种工艺涉及的生化过程复杂,影响因素众多,难以有效去除PPCPs。数学模型是污水处理工艺运行优化的重要工具。本文系统阐述了PPCPs去除模型的建立方法,包括物质和微生物组分及PPCPs去除过程的确定、动力学方程及关键系数的测定与校准、活性污泥和生物膜模型的异同等;综述了污水中PPCPs去除模型的应用研究进展,包括用于评价不同微生物对PPCPs的降解性能、探究污水中PPCPs的生物降解机制及限制因素、优化影响PPCPs去除的参数等,为精准调控污水中PPCPs去除提供参考。 相似文献
110.
Daniela Canestrari José M. Marcos Vittorio Baglione 《Behavioral ecology and sociobiology》2005,57(5):422-428
Carrion crows Corvus corone corone in northern Spain form complex cooperative groups that contain non-dispersing offspring and immigrants. Reproduction is often shared among group members, with polyandry prevalent over joint egg laying. However, due to incest avoidance or sexual immaturity, reproduction is potentially available only to a fraction of group members (potential breeders), while others do not breed (non-breeders). We combined molecular data with video-recorded observations at nests in order to investigate whether potential breeders and non-breeders adjust their individual effort in nestling feeding respectively to their level of parentage and the relatedness with the chicks. Overall, parents of at least one chick in the brood showed the highest feeding rates. Among potential breeders, genetic mothers and fathers fed chicks at significantly higher rates than individuals with no parentage, but they did not adjust their effort according to the proportion of offspring generated. Current direct fitness benefits are therefore important in determining a high provisioning effort, but crows may lack a mechanism to finely assess their share of parentage. Among non-breeders, males contributed more than females to chick feeding, but we found no significant correlation between feeding rate and relatedness to the nestling. We discuss how the latter result can be reconciled with the fact that kin selection has been shown to be important in shaping the crow cooperative society.Communicated by C. Brown 相似文献