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51.
James O. Luken Steven W. Beiting Scott K. Kareth Robyn L. Kumler Jun H. Liu Craig A. Seither 《Environmental management》1994,18(2):251-255
We tested two cutting regimens (cut/spray and cut/delay spray) and four radiarc-applied herbicides (Garlon + Tordon, Accord,
Accord + Escort, and Krenite) in an Ohio power-line corridor to determine which management combination best eliminated target
species (i.e., trees) and preserved nontarget species (i.e., low shrubs, vines, perennial herbs, and grasses).
When spraying was delayed after cutting, the herbicide with the least impact on nontarget species (Krenite) also was least
efficient at killing target trees. Spraying soon after cutting improved tree-killing efficiency of several herbicides, but
it also increased the negative impact on nontarget species. The herbicide with the most consistent tree-killing ability (Accord
+ Escort) had the most impact on nontarget species.
Because none of the herbicide/cutting treatments performed ideally, resource managers must decide the acceptable impact on
nontarget species when considering herbicide use. Future success of herbicides as part of an integrated succession management
approach requires more selective application methods and formulations so that target effects can be maximized and nontarget
effects can be minimized. 相似文献
52.
Host intra-clutch variation,cuckoo egg matching and egg rejection by great reed warblers 总被引:3,自引:1,他引:2
Prevailing theory predicts that lower levels of intra-clutch variation in host eggs facilitate the detection of brood parasitism.
We assessed egg matching using both human vision and UV-VIS spectrophotometry and then followed the nest fate of great reed
warblers naturally parasitised by European cuckoos. Rejection was predicted by the following three variables: matching between
cuckoo and host eggs on the main chromatic variable defined by principal components analysis of the egg spectra (which has
a strong loading in the UV); the number of host eggs in the nest; and human estimates of intra-clutch variation. The first
variable is not correlated to human estimates of matching, which do not predict rejection. In line with another recent study,
rejection rates were predicted by higher levels of intra-clutch variation in the host eggs, suggesting that higher rather
than lower levels of intra-clutch variation can facilitate the discrimination of cuckoo eggs by hosts. We suggest that the
importance of intra-clutch variation is context dependent, with intra-clutch variation being important when there is good
matching between the host and the cuckoo eggs. Our results also suggest that both spectrometric and human visual assessments
of egg matching and intra-clutch variation are prudent: the former provide the best method of estimating reflectance variation,
whereas the latter include some assessment of patterns of maculation. 相似文献
53.
Although colonies of the fire ant Solenopsis invicta are often founded by small groups of queens, all but one of the queens are soon eliminated due to worker attacks and queen
fighting. The elimination of supernumerary queens provides an important context for tests of discrimination by the workers,
since the outcome of these interactions strongly affects the workers' inclusive fitness. To test whether workers in newly
founded colonies discriminate among nestmate queens, paired cofoundresses were narrowly separated by metal screens that prevented
direct fighting, but through which the workers could easily pass. Soon after the first workers completed development, they
often attacked one of the queens; these attacks were strongly associated with queen mortality. When one queen's brood was
discarded, so that the adult workers were all the daughters of just one queen, the workers were significantly less likely
to bite their mother than the unrelated queen; however, this tendency was comparatively weak. Queens kept temporarily at a
higher temperature to increase their rate of investment in brood-rearing lost weight more rapidly than paired queens and were
subsequently more likely to be attacked and killed by workers. Workers were more likely to bite queens that had been temporarily
isolated than queens that remained close to brood and workers. When queens were not separated by screens, the presence of
workers stimulated queen fights. These results show that workers discriminate strongly among equally familiar queens and that
discrimination is based more on the queens' condition and recent social environment than on kinship.
Received: 9 June 1998 / Accepted after revision: 10 October 1998 相似文献
54.
William E. Cooper Jr. 《Chemoecology》1999,9(4):155-159
Summary. Lingually mediated prey chemical discrimination in lizards has evolved in active foragers, been lost in taxa that have reverted
to ambush foraging, and has not evolved in taxa that have retained the ancestral ambushing. Previous studies have shown that
all families of insectivorous ambushers lack prey chemical discrimination, including most families of iguanian lizards and
two gekkonid species. I conducted experimental studies of prey chemical discrimination in representatives of two additional
iguanian families and a third gekkonid lizard. An oplurid species, Oplurus cuvieri and a corytophanid, Corytophanes cristatus, did not discriminate among prey chemicals and control substances. Prey chemical discrimination is now known to be absent
in insectivorous ambush foragers in all but one of the families in Iguania, one of the two major lizard radiations. Hoplocercidae
remains unstudied. Like other ambushing gekkonid lizards, Pachydactylus turneri did not exhibit elevated tongue-flick rates in response to prey chemicals. However, after tongue-flicking or being touched
on the labial scales by cotton swabs, these lizards bit swabs bearing prey chemicals more frequently than control stimuli.
They also exhibited buccal pulsing more frequently in response to prey chemicals than deionized water, suggesting olfactory
sampling. The unusually highly developed olfactory organs of gekkonid lizards and their nocturnal habits suggest that olfaction
may be more important to foraging than in other lizards. Further studies are needed to determine relative roles of olfaction
and vomerolfaction in selective response to prey chemicals and to ascertain whether and to what extent the tongue may be used
to locate and identify prey.
Received 30 March 1999; accepted 26 July 1999 相似文献
55.
水源地水污染风险等级判别方法及应用 总被引:3,自引:1,他引:2
以广西柳州市柳南水厂水源地为研究对象,建立了水源地风险等级判别模型,模型主要考虑企业风险等级,以及风险影响后水源地水质超标倍数、水质超标持续时间、污染团到达时间等因子,模型参数根据调查及分析得到。通过风险判别模型,计算得到柳南水厂取水口的风险等级,为该区域进行环境风险管理提供了技术支撑。 相似文献
56.
Kinship and aggression: do house sparrows spare their relatives? 总被引:1,自引:0,他引:1
Zoltán Tóth Veronika Bókony Ádám Z. Lendvai Krisztián Szabó Zsolt Pénzes András Liker 《Behavioral ecology and sociobiology》2009,63(8):1189-1196
Kin-selection theory predicts that relatedness may reduce the level of aggression among competing group members, leading to
indirect fitness benefits for kin-favoring individuals. To test this hypothesis, we investigated whether relatedness affects
aggressive behavior during social activities in captive house sparrow (Passer domesticus) flocks. We found that sparrows did not reduce their aggression towards kin, as neither the frequency nor the intensity of
fights differed between close kin and unrelated flock-mates. Fighting success was also unrelated to kinship and the presence
of relatives in the flock did not influence the birds’ dominance rank. These results suggest that the pay-offs of reduced
aggression towards kin may be low in non-breeding flocks of sparrows, e.g. due to competition among relatives as predicted
by a recent refinement of kin-selection theory. Our findings indicate that the significance of kin selection may be restricted
in some social systems such as winter aggregations of birds.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
57.
Foundresses of the social wasp Polistes biglumis were tested to see whether they were able to recognize alien eggs experimentally introduced into their own nests. Foundresses
removed alien conspecific reproductive-destined eggs while they accepted worker-destined eggs. The results indicate that social
wasps discriminate among eggs and that they discriminate against alien eggs destined to produce unrelated reproductives. P. biglumis is a strictly solitary founding species, with no reproductive competition within colonies; thus, brood discrimination abilities
could have evolved as a counteradaptation against intra- and inter-specific brood parasitism.
Received: 12 May 2000 / Revised: 15 July 2000 / Accepted 20 July 2000 相似文献
58.
The social environment of many species includes synchronous maturation of siblings in family groups, followed by limited dispersal
of adults from their natal site. Under these conditions, females may experience high encounter rates with same-age siblings
during mate searching, increasing their risk of inbreeding. If inbreeding depression occurs, mating with a sibling is often
considered maladaptive; however, in some contexts, the inclusive fitness benefits of inbreeding may outweigh the costs, favoring
females that tolerate some level of inbreeding depression. We evaluated mating patterns in the treehopper Umbonia crassicornis, a semelparous species in which females encounter same-age siblings during mate searching. A female U. crassicornis that mates with a brother suffers from inbreeding depression. We used a free-choice mating design that offered females simultaneous
mating opportunities with three groups of males: siblings, same-age nonsiblings, and older nonsiblings. These groups represent
the types of males typically encountered by females during mate searching. Our goal was to assess whether mating patterns
were influenced by inbreeding avoidance by evaluating two hypotheses: kin discrimination and age-based mating (older males
cannot be siblings in this species). There was no difference in the proportions of females mating with siblings vs nonsiblings,
suggesting an absence of kin discrimination. However, females mated with a greater proportion of older vs younger males. Given
that females do not avoid siblings as mates despite a cost to inbreeding, our results provide a possible example of inbreeding
tolerance. We also discuss some factors that may have contributed to the mating advantage of older males. 相似文献
59.
Learning is generally predicted not to be important in host discrimination by parasitoids, because the stimuli involved are
less variable than those used in habitat location. However, Anaphes victus (Hymenoptera: Mymaridae), an egg parasitoid of Listronotus oregonensis (Coleoptera: Curculionidae) apparently learns to associate external pheromones with the presence of a conspecific in a host.
In this species, females can reject a parasitized host either after antennal drumming (antennal rejection) or after the insertion
of their ovipositor (sting rejection). When they encountered a series of parasitized hosts, females A. victus learned to associate the presence of the external pheromone with the presence of the internal one. Learning lasted less than
4 h and occurred earlier in a series when the female marking the egg and the one detecting that mark were close relatives.
This behavior could be adaptive because antennal rejection is faster than sting rejection.
Received: 11 March 1997 / Accepted after revision: 30 August 1997 相似文献
60.
《组织行为杂志》2017,38(1):124-151
The Workplace Intergenerational Climate Scale (WICS) is designed to measure employees' attitudes and perceptions about workers of different ages in the workplace. In Study 1, an initial 18‐item measure was developed, reflecting five subscales: Intergenerational Contact, Workplace Intergenerational Retention, Positive Intergenerational Affect, Workplace Generational Inclusiveness, and Lack of Generational Stereotypes. Scores on the five WICS subscales were linked to workplace mentoring, opinions about older workers, and job satisfaction. In Study 2, the WICS items and subscales were further refined, and subscale relationships with similar constructs were explored via structural equation modeling. In Study 3, a more occupationally diverse sample was used to support criterion, incremental, discriminant, and external validity. Evidence supports the use of the WICS as a valid and reliable multidimensional measure of an organization's intergenerational climate. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献