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851.
Naiara Albaina Jeanine L. Olsen Lucía Couceiro José Miguel Ruiz Rodolfo Barreiro 《Marine Biology》2012,159(9):1871-1884
Because marine species respond differentially to factors governing survival and gene flow, closely related taxa may display dissimilar phylogeographic histories. New data for the patchily distributed gastropod Nassarius nitidus throughout its Atlantic–Mediterranean range (collected during 2008 and 2009) were used to investigate its phylogeography and recent demography. Results based on mitochondrial COI sequences of 422?N. nitidus individuals from 15 localities revealed contrasting phylogeographic and demographic patterns among N. nitidus populations from each basin. Data suggest the existence of two glacial refugia, one in the Atlantic, around the Iberian Peninsula, and the other in the Paleo-Mediterranean Sea (Adriatic). Bayesian skyline reconstructions suggest that the Adriatic population of N. nitidus remained largely unaffected by the Last Glacial Maximum (LGM), whereas the Iberian Atlantic region experienced dramatic exponential growth after its conclusion. Contemporary North Sea populations of N. nitidus are the endpoint of a leading-edge recolonization process from a southern position. Additionally, a reanalysis of pre-existing material for the continuously distributed close congener N. reticulatus was used to compare both species in the late histories. In contrast to N. nitidus, N. reticulatus prospered during the LGM and experienced an earlier Atlantic expansion during the previous interglacial period. Despite similar life history and dispersal potential, the results here presented suggest that subtle differences in microhabitat requirements between the two species have had important consequences for their particular distribution in response to glacial events. 相似文献
852.
Eduardo Madrigal-Santillán Eduardo Madrigal-Bujaidar Alicia Reyes-Arellano José Antonio Morales-González Isela Álvarez-González Manuel Sánchez-Gutiérrez 《毒物与环境化学》2019,101(7-8):369-388
AbstractGlucomannan is a highly branched polysaccharide with glycosidic linkages, constituted of mannoses and glucoses. In recent years, its usefulness due to its immunological, antioxidant and antimutagenic activity has been recognized. The aim of the study was to determine the antigenotoxic ability of glucomannan extracted from Candida utilis orally administered (100–700?mg/kg) to mice, which subsequently received 1?mg/kg aflatoxin B1. Hepatocytes obtained from these animals 4–16?h post administration were examined by means of the comet assay. The antigenotoxic effect was found to be higher than that observed in previous studies with α-mannan and β-D-glucan isolated from Saccharomyces cerevisiae., In order to explore the possibility of formation of a supramolecular complex between glucomannan and aflatoxin B1, both compounds were co-crystallized, their melting points determined, and the complex analyzed through ultraviolet spectroscopy. The spectroscopy data suggest that the protective effect of glucomannan is related to the formation of a supramolecular complex between the two compounds. 相似文献
853.
Virginie Marques Paul Castagné Andréa Polanco Fernández Giomar Helena Borrero-Pérez Régis Hocdé Pierre-Édouard Guérin Jean-Baptiste Juhel Laure Velez Nicolas Loiseau Tom Bech Letessier Sandra Bessudo Alice Valentini Tony Dejean David Mouillot Loïc Pellissier Sébastien Villéger 《Conservation biology》2021,35(6):1944-1956
Assessing the impact of global changes and protection effectiveness is a key step in monitoring marine fishes. Most traditional census methods are demanding or destructive. Nondisturbing and nonlethal approaches based on video and environmental DNA are alternatives to underwater visual census or fishing. However, their ability to detect multiple biodiversity factors beyond traditional taxonomic diversity is still unknown. For bony fishes and elasmobranchs, we compared the performance of eDNA metabarcoding and long-term remote video to assess species’ phylogenetic and functional diversity. We used 10 eDNA samples from 30 L of water each and 25 hr of underwater videos over 4 days on Malpelo Island (pacific coast of Colombia), a remote marine protected area. Metabarcoding of eDNA detected 66% more molecular operational taxonomic units (MOTUs) than species on video. We found 66 and 43 functional entities with a single eDNA marker and videos, respectively, and higher functional richness for eDNA than videos. Despite gaps in genetic reference databases, eDNA also detected a higher fish phylogenetic diversity than videos; accumulation curves showed how 1 eDNA transect detected as much phylogenetic diversity as 25 hr of video. Environmental DNA metabarcoding can be used to affordably, efficiently, and accurately census biodiversity factors in marine systems. Although taxonomic assignments are still limited by species coverage in genetic reference databases, use of MOTUs highlights the potential of eDNA metabarcoding once reference databases have expanded. 相似文献
854.
855.
Tiago José Pereira Gustavo Fonseca Manuel Mundo-Ocampo Betânia Cristina Guilherme Axayácatl Rocha-Olivares 《Marine Biology》2010,157(8):1665-1678
We used morphological and molecular approaches to evaluate the diversity of free-living marine nematodes (order Enoplida)
at four coastal sites in the Gulf of California and three on the Pacific coast of Baja California, Mexico. We identified 22
morphological species belonging to six families, of which Thoracostomopsidae and Oncholaimidae were the most diverse. The
genus Mesacanthion (Thoracostomopsidae) was the most widespread and diverse. Five allopatric species, genetically and morphologically differentiated,
were found in two localities in the Gulf of California (M. sp1 and M. sp2) and three in the Pacific coast (M. sp3, M. sp4 and M. sp5). Overall, we produced 19 and 20 sequences for the 18S and 28S genes, respectively. Neither gene displayed intraspecific
polymorphisms, which allowed us to establish that some morphological variation was likely either ontogenetic or due to phenotypic
plasticity. Although 18S and 28S phylogenies were topologically congruent (incongruence length difference test, P > 0.05), divergences between species were much higher in the 28S gene. Moreover, this gene possessed a stronger phylogenetic
signal to resolve relationships involving Rhabdodemania and Bathylaimus. On the other hand, the close relationship of Pareurystomina (Enchilidiidae) with oncholaimids warrants further study. The 28S sequences (D2D3 domain) may be better suited for DNA barcoding
of marine nematodes than those from the 18S rDNA, particularly for differentiating closely related or cryptic species. Finally,
our results underline the relevance of adopting an integrative approach encompassing morphological and molecular analyses
to improve the assessment of marine nematode diversity and advance their taxonomy. 相似文献
856.
Olivier Pays Simon P. Blomberg Pierre-Cyril Renaud François-René Favreau Peter J. Jarman 《Behavioral ecology and sociobiology》2010,64(3):443-454
In group-forming prey species, theory assumes that individuals within groups should scan independently of one another, with
vigilance sequences being relatively unpredictable, making interscan durations highly variable. We attempted to detect any
divergence from randomness in the scanning process in three mammalian prey species phylogenetically and geographically separated
and exposed to different levels of predation: waterbuck, Kobus ellipsiprymnus defassa, under a high observed predation risk, eastern grey kangaroo, Macropus giganteus, still experiencing occasional predation and European roe deer, Capreolus capreolus, under a very low natural predation risk. Our results revealed that the focal interscan duration increased when the duration
of the preceding interscan increased, whatever the studied species and the predation risk that its individuals experienced,
and decreased with the preceding scan duration in two species under, respectively, occasional and low predation risks. The
exponential distribution was the tested model that fitted the observed distributions of interscan durations least well. We
discuss what can trigger non-randomness in scanning, through a non-homogenous Poisson process, at both intra-individual and
inter-individual levels, particularly with regard to previous studies that have demonstrated synchronisation of vigilance
in such mammals. Our results suggest the need to reconsider any assumption of randomness in scanning in the basic model predicting
form and frequency of scanning behaviour by prey species. 相似文献
857.
René E. van Dijk Lidia A. Mészáros Marco van der Velde Tamás Székely Ákos Pogány János Szabad Jan Komdeur 《Behavioral ecology and sociobiology》2010,64(9):1425-1435
Engagement in extra-pair copulations is an example of the abundant conflicting interests between males and females over reproduction.
Potential benefits for females and the risk of cuckoldry for males are expected to have important implications on the evolution
of parental care. However, whether parents adjust parental care in response to parentage remains unclear. In Eurasian penduline
tits Remiz pendulinus, which are small polygamous songbirds, parental care is carried out either by the male or by the female. In addition, one
third of clutches is deserted by both male and female. Desertion takes place during the egg-laying phase. Using genotypes
of nine microsatellite loci of 443 offspring and 211 adults, we test whether extra-pair paternity predicts parental care.
We expect males to be more likely to desert cuckolded broods, whereas we expect females, if they obtain benefits from having
multiple sires, to be more likely to care for broods with multiple paternity. Our results suggest that parental care is not
adjusted to parentage on an ecological timescale. Furthermore, we found that male attractiveness does not predict cuckoldry,
and we found no evidence for indirect benefits for females (i.e., increased growth rates or heterozygosity of extra-pair offspring).
We argue that male Eurasian penduline tits may not be able to assess the risk of cuckoldry; thus, a direct association with
parental care is unlikely to evolve. However, timing of desertion (i.e., when to desert during the egg-laying phase) may be
influenced by the risk of cuckoldry. Future work applying extensive gene sequencing and quantitative genetics is likely to
further our understanding of how selection may influence the association between parentage and parental care. 相似文献
858.
Mireia Andrés Alicia Estévez Francisco Hontoria Guiomar Rotllant 《Marine Biology》2010,157(10):2329-2340
Changes in lipid class, fatty acid, fat-soluble vitamins, amino acid and minerals were studied during larval development of
Maja brachydactyla Balss, 1922 in order to provide information of its ontogeny and evaluate possible dietary deficiencies and constraints. Four
different batches were analyzed from hatching to metamorphosis using enriched Artemia as food. Cultured larvae were in a good nutritional condition as confirmed by the continuous lipid accumulation throughout
ontogeny. A regulation of polyunsaturated fatty acids (PUFA) occurred during development in order to maintain adequate basal
levels of ω-3 fatty acids (likely through a retro conversion of C20 and C22 into C18 PUFA). Variations in the tocopherol levels indicated its possible role in PUFA protection against oxidation. Essential amino
acid balance during development was not correlated with the Artemia feeding regime, but rather reflected inherent variations of the own species ontogeny. Larval requirements in essential minerals
were fully supplied by the enriched Artemia. 相似文献
859.
Luiz Duczmal Ricardo Tavares Ganapati Patil André L. F. Cançado 《Environmental and Ecological Statistics》2010,17(2):183-202
We propose a novel tool for testing hypotheses concerning the adequacy of environmentally defined factors for local clustering
of diseases, through the comparative evaluation of the significance of the most likely clusters detected under maps whose
neighborhood structures were modified according to those factors. A multi-objective genetic algorithm scan statistic is employed
for finding spatial clusters in a map divided in a finite number of regions, whose adjacency is defined by a graph structure.
This cluster finder maximizes two objectives, the spatial scan statistic and the regularity of cluster shape. Instead of specifying
locations for the possible clusters a priori, as is currently done for cluster finders based on focused algorithms, we alter
the usual adjacency induced by the common geographical boundary between regions. In our approach, the connectivity between
regions is reinforced or weakened, according to certain environmental features of interest associated with the map. We build
various plausible scenarios, each time modifying the adjacency structure on specific geographic areas in the map, and run
the multi-objective genetic algorithm for selecting the best cluster solutions for each one of the selected scenarios. The
statistical significances of the most likely clusters are estimated through Monte Carlo simulations. The clusters with the
lowest estimated p-values, along with their corresponding maps of enhanced environmental features, are displayed for comparative analysis. Therefore
the probability of cluster detection is increased or decreased, according to changes made in the adjacency graph structure,
related to the selection of environmental features. The eventual identification of the specific environmental conditions which
induce the most significant clusters enables the practitioner to accept or reject different hypotheses concerning the relevance
of geographical factors. Numerical simulation studies and an application for malaria clusters in Brazil are presented. 相似文献
860.
Cypermethrin (CY) is an active cyano pyrethroid effective against a wide range of pests encountered in agriculture and forestry. Although CY is not mutagenic in in vitro assays for gene mutation, in vivo assays showed conflicting results. In vivo genotoxicity of the synthetic pyrethroid CY in erythrocytes of Odontophrynus americanus tadpoles was examined. The frequency of micronuclei (MN) was recorded in blood smears obtained from tadpoles exposed in vivo to four different nominal concentrations 5, 10, 20 or 40?µg?L?1 of the compound and fixed at two sampling times 48 and 96?h. As a positive control larvae were exposed to 40?mg?L?1 of cyclophosphamide (CP). Tadpoles exposed to all CY treatments showed a significant increase in single small MN compared to the negative control group after 48?h and at 5 and 10?µg?L?1 of CY at 96?h. Results obtained here demonstrated the genotoxic effects of the commercial formulation CY in the anuran larvae analyzed. Thus, data suggest that measurements of MN and other erythrocytes morphological aberrations performed in circulating blood samples of O. americanus tadpoles is a method for detecting cytogenetic damage in other native species. 相似文献