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The patterns of genetic diversity and connectivity were investigated in Cucumaria frondosa, the most abundant sea cucumber in the North Atlantic, to assist in the management and conservation of this ecologically
important marine invertebrate, which is the target of an emerging fishery. Mitochondrial DNA COI sequences of 334 C. frondosa were obtained and analyzed, mainly from its western North Atlantic range, where the commercial fishery is being developed,
with complementary sampling in the mid- and eastern North Atlantic. Analysis of molecular variance showed no significant (P > 0.05) differences among subpopulations in the western region suggesting that it constitutes one panmictic population. The
same analysis showed low, but significant differences between eastern and western Atlantic populations. Coalescent analyses
using isolation with migration models and a Bayesian skyline plot indicated historical divergence and a general increase in
population size prior to the last glacial maximum and highly asymmetric gene flow (nearly 100 times lower from west to east)
between sea cucumbers from North America and Norway. Results suggest that subpopulations of C. frondosa within the western North Atlantic have been highly connected. We propose that aided by the high-connectivity local subpopulations
can recover rapidly from natural (i.e., ice ages) or anthropogenic (i.e., overfishing) population declines through recruitment
from deep refugia. 相似文献
24.
A fundamental question of sexual selection theory concerns the causes and consequences of reproductive skew among males. The
priority of access (PoA) model (Altmann, Ann NY Acad Sci 102:338–435, 1962) has been the most influential framework in primates living in permanent, mixed-sex groups, but to date it has only been
tested with the appropriate data on female synchrony in a handful of species. In this paper, we used mating data from one
large semi-free ranging group of Barbary macaques: (1) to provide the first test of the priority-of-access model in this species,
using mating data from 11 sexually active females (including six females that were implanted with a hormonal contraceptive
but who showed levels of sexual activity comparable to those of naturally cycling females) and (2) to determine the proximate
mechanism(s) underlying male mating skew. Our results show that the fit of the observed distribution of matings with sexually
attractive females to predictions of the PoA model was poor, with lower-ranking males mating more than expected. While our
work confirms that female mating synchrony sets an upper limit to monopolization by high-ranking individuals, other factors
are also important. Coalitionary activity was the main tactic used by males to lower mating skew in the study group. Coalitions
were expressed in a strongly age-related fashion and allowed subordinate, post-prime males to increase their mating success
by targeting more dominant, prime males. Conversely, females, while mating promiscuously with several males during a given
mating cycle, were more likely to initiate their consortships with prime males, thus reducing the overall effectiveness of
coalitions. We conclude that high-ranking Barbary macaque males have a limited ability to monopolize mating access, leading
to a modest mating skew among them. 相似文献
25.
Christel Thauvin-Robinet Thierry Rousseau Christine Durand Nicole Laurent Catherine Maingueneau Laurence Faivre Paul Sagot Annie Nivelon-Chevallier 《黑龙江环境通报》2001,21(6):466-470
Porencephaly is a rare central nervous system (CNS) abnormality that can be caused by an intraparenchymal destructive process or a developmental defect. Here we report on a prenatal ultrasound diagnosis of complex CNS abnormalities including agenesis of the corpus callosum, agenesis of the cerebellar vermis, bilateral hydrocephaly, and bilateral porencephaly in fetus at 33 weeks' gestation. The diagnosis of familial orofaciodigital syndrome type I (OFD I) was raised after fetal autopsy, clinical examination of the family, and the X-linked dominant inheritance pattern. This is the fourth report of porencephaly in association with OFD I. We discuss the difficulties in genetic counselling since OFD I shows variable expressivity of the phenotypic features. Furthermore, we emphasize the importance of a detailed ultrasound examination after a prenatal diagnosis of porencephaly. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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This study developed an objective quantitative method for detecting small-scale temporal or spatial differences in gametogenesis
in echinoderms. The method was applied to conventional monthly samples of the planktotrophic brittle star, Ophiopholis aculeata, collected at a single site in Newfoundland (eastern Canada) at 10–15 m depth. The samples were analysed to determine gonad
index, oocyte size and gonadal stage using histology. The maturity stage index (MSI) was developed to integrate a measure
of brittle star size (disc diameter), oocyte size and oocyte density. The MSIs ranged from 0 to 800 and had significantly
different means among the four gametogenic stages (early growth, growth, mature and spent). The MSI was more sensitive in
revealing significant differences between consecutive stages than any of its individual constituents. The MSI was also applied
to gametogenic data from the lecithotrophic holothuroid, Mesothuria lactea, again revealing significant differences between successive oogenic stages. This method is expected to be useful in field
and experimental studies of gametogenesis in echinoderms (and possibly other taxa), where it is important to detect not just
the timing of annual peaks in reproduction but small differences in reproductive status among individuals or populations (e.g.
from different habitats or feeding regimes). 相似文献
28.
Erin A. Falcone Gregory S. Schorr Annie B. Douglas John Calambokidis Elizabeth Henderson Megan F. McKenna John Hildebrand David Moretti 《Marine Biology》2009,156(12):2631-2640
The relationship between beaked whales and certain anthropogenic sounds remains poorly understood and of great interest. Although
Cuvier’s beaked whales (Ziphius cavirostris) are widely distributed, little is known of their behavior and population structure throughout much of their range. We conducted
a series of five combined visual-acoustic marine mammal surveys from 2006 to 2008 in the southern San Nicolas Basin, a site
of frequent naval activity off the southern California coast, west of San Clemente Island. The study area was defined by a
1,800 km2 array of 88 bottom-mounted hydrophones at depths up to 1,850 m. The array was used to vector visual observers toward vocalizing
marine mammal species. Thirty-seven groups of Cuvier’s beaked whales were encountered during the study period. The overall
encounter rate was one group for every 21.0 h of survey effort, and was as high as one group per 10.2 h of effort during the
October 2007 survey. Whales were encountered in the deepest portion of the study area, at a mean bottom depth of 1,580 m (SD
138). The average group size was 3.8 individuals (SD 2.4), which was higher than has been reported from other studies of this
species. Twenty-four groups were observed over multiple surfacings (median = 4 surfacings, range 2–15). The mean encounter
duration of extended sightings was 104 min (SD 98, range 12–466 min) and the mean distance moved over the course of sightings
was 1.66 km (SD 1.56, range 0.08–6.65 km). Temporal surfacing patterns during extended encounters were similar to dive behavior
described from Cuvier’s beaked whales carrying time-depth recording tags. Seventy-eight photographic identifications were
made of 58 unique individuals, for an overall resighting rate of 0.26. Whales were sighted on up to 4 days, with duration
from first to last sighting spanning 2–79 days. For those whales sighted on subsequent days, the mean distance between subsequent
sightings was 8.6 km (SD 7.9). Individuals resighted over 2–3 days were usually in association with previous group members.
Approximately one-third of groups contained more than one adult male, and many of the repeated associations involved adult
males. These observations suggest the basin west of San Clemente Island may be an important region for Cuvier’s beaked whales,
and also one which affords an unusual opportunity to collect detailed data on this species. Given its status as an active
military range, it can also provide the ability to monitor the behavior of individuals in the presence of naval sonar, a critical
step in the management of this and other beaked whale populations worldwide. 相似文献
29.
Philippe Lucas‐Picher Simon Lachance‐Cloutier Richard Arsenault Annie Poulin Simon Ricard Richard Turcotte Franois Brissette 《Journal of the American Water Resources Association》2021,57(1):32-56
In spring 2011, an unprecedented flood hit the complex eastern United States (U.S.)–Canada transboundary Lake Champlain–Richelieu River (LCRR) Basin, destructing properties and inducing negative impacts on agriculture and fish habitats. The damages, covered by the Governments of Canada and the U.S., were estimated to C$90M. This natural disaster motivated the study of mitigation measures to prevent such disasters from reoccurring. When evaluating flood risks, long‐term evolving climate change should be taken into account to adopt mitigation measures that will remain relevant in the future. To assess the impacts of climate change on flood risks of the LCRR basin, three bias‐corrected multi‐resolution ensembles of climate projections for two greenhouse gas concentration scenarios were used to force a state‐of‐the‐art, high‐resolution, distributed hydrological model. The analysis of the hydrological simulations indicates that the 20‐year return period flood (corresponding to a medium flood) should decrease between 8% and 35% for the end of the 21st Century (2070–2099) time horizon and for the high‐emission scenario representative concentration pathway (RCP) 8.5. The reduction in flood risks is explained by a decrease in snow accumulation and an increase in evapotranspiration expected with the future warming of the region. Nevertheless, due to the large climate inter‐annual variability, short‐term flood probabilities should remain similar to those experienced in the recent past. 相似文献
30.
Annie Allen 《国际发展与全球生态学杂志》2018,25(6):483-490
This paper explores challenges in reconciling the cultural, economic and ecological pillars of the sustainable development concept. It does so by examining how conflicts in the management of an island off the Irish coast called Skellig Michael, which has been internationally designated for its significant cultural and ecological attributes, have been intensified by: (a) increasing tourist numbers; (b) a re-framing of the site’s identity and (c) changing visitor motivations. These have resulted from the amplified attention the island has received following the release of Star Wars: The Force Awakens and The Last Jedi in which it features prominently. Following a critical identification and discussion of the fault lines between different stakeholders involved in the conservation and use of the island, the paper advances a roadmap for action to help resolve animosity in the governance of the site and facilitate its sustainable management in the context of changing visitor numbers and profiles. 相似文献