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排序方式: 共有421条查询结果,搜索用时 15 毫秒
301.
Patrick Gautier Marco Barroca Sophie Bertrand Cyril Eraud Maria Gaillard Michael Hamman Sébastien Motreuil Gabriele Sorci Bruno Faivre 《Behavioral ecology and sociobiology》2008,62(7):1159-1166
Several environmental factors have been shown to shape the pattern of investment of carotenoids into the expression of sexual
signals. Surprisingly, the impact of the social environment has been neglected. If a carotenoid-based sexual trait is used
by females to choose a mate or by males to assess the quality of potential competitors for mates, males, in the presence of
females, should upregulate expression of the trait. We tested this hypothesis in male zebra finches that were housed either
with females or in a male-only social environment. Additionally, to investigate whether the social modulation of the expression
of a sexual trait depends on the physiological need of carotenoids, we challenged half of the males with Escherichia coli lipopolysaccharide (LPS). We found that the social environment modulated the expression of bill color, with males kept in
the presence of females harboring a redder bill at the end of the 3 weeks that the experiment lasted. Males injected with
LPS showed duller bill color regardless of the presence of females, and social interactions with females result in upregulated
bill color similarly for phosphate-buffered saline (PBS) and LPS males. Thus, social environment and immune activation had
an additive effect on the expression of bill color. The effect of social environment on plasma carotenoids was less clear.
Indeed, a first replicate of the entire experiment showed that both immune challenge and social context affected bill color,
with a negative effect of immune challenge and a positive effect of the presence of females on circulating carotenoids. However,
a second replicate of the experiment showed only a negative effect of the immune challenge. These results, therefore, suggest
that the social environment can affect the expression of carotenoid-based sexual traits under both benign and carotenoid-demanding
conditions. Whatever the signaling function of bill color (female mate choice or male–male competition for mates), the observed
flexibility may be adaptive because the expression of the signal can be modulated depending on the expected rewards or costs
associated with the presence or absence of females. Nevertheless, the mechanisms underlying such an effect are still unknown. 相似文献
302.
Bruno David Stuart R. Stock Francesco De Carlo Vincent Hétérier Chantal De Ridder 《Marine Biology》2009,156(8):1559-1572
The echinoderm endoskeleton, located in the connective layer of the tegument, is organized into a three-dimensional mesh,
the stereom. Among echinoids, the cidaroids depart from this pattern, and the shaft of the spine lacks an epidermis. Thus,
the spines lack antifouling protection, allowing ectosymbionts such as bryozoans and foraminiferans to attach. This raises
a question about the adaptive role of the cortical layer of the stereom. This study examined the micro- and mesostructure
of the spines of 11 cidaroid species collected in the Weddell Sea and Drake Passage, and the nature of their ectosymbiont
attachments. Scanning electron microscopy was used to characterize the cortex surface and X-ray micro computed tomography
(μCT) to describe the symbiont attachments. Spine microstructure features provide a useful taxonomic character for distinguishing
among three species in the genus Ctenocidaris, and challenge a previous parasitic interpretation of cortical filaments on the spines of Rhynchocidaris triplopora. Ectosymbiont attachments were classified as Anchoring, Molding, Cementing, or Corroding. The study suggests that some microstructure
features may be protective, keeping the ectosymbionts away from the cortex and loosely attached at intervals along the shaft
of the spine, while other micro-structures facilitate attachment over considerable areas of the shaft.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
303.
Soil microbial diversity and C turnover modified by tillage and cropping in Laos tropical grassland 总被引:3,自引:0,他引:3
Pascal Lienhard Sébastien Terrat Olivier Mathieu Jean Levêque Nicolas Chemidlin Prévost-Bouré Virginie Nowak Tiffanie Régnier Céline Faivre Sengphanh Sayphoummie Khamkéo Panyasiri Florent Tivet Lionel Ranjard Pierre-Alain Maron 《Environmental Chemistry Letters》2013,11(4):391-398
Agricultural practices should modify the diversity of soil microbes. However, the precise relationships between soil properties and microbial diversity are poorly known. Here, we study the effect of agricultural management on soil microbial diversity and C turnover in tropical grassland of north-eastern Laos. Three years after native grassland conversion into agricultural land, we compared soils from five land use management systems: one till versus two no-till rotational cropping systems, one no-till improved pasture and the natural grassland. Soils were incubated in microcosms during 64 days at optimum temperature and humidity. Bacterial and fungal diversity were evaluated by metagenomic 454-pyrosequencing of 16S and 18SrRNA genes, respectively. Changes in soil respiration patterns were evaluated by monitoring 12C- and 13C-CO2 release after soil amendment with 13C-labelled wheat residues. Results show that residue mineralization increased with bacterial richness and diversity in the tilled treatment 7 days after soil amendment. Native soil organic C mineralization and priming effect increased with fungal richness and diversity in improved pasture and natural grassland. No-till cropping systems represented intermediate situations between tillage and pasture systems. Our findings evidence the potential of controlling soil microbial diversity by agricultural practices to improve soil biological properties. We suggest the promotion of no-till systems as a fair compromise between the need for agriculture intensification and soil ecological processes preservation. 相似文献
304.
305.
Irène Korsakissok Vivien Mallet Bruno Sportisse 《Atmospheric environment (Oxford, England : 1994)》2010,44(3):408-420
We propose a method to evaluate the detection abilities of networks used for protection purposes. Such networks are designed for the detection of nuclear, biological or gaseous emissions, without constraint on the source location. Their assigned goal is to have the best chance to detect a threatening emission located anywhere in the vicinity of a domain to protect. Two sensors siting applications are addressed: sensors placed in the surroundings of a facility to protect, or sensors carried by people scattered within a small area. A network protection ability is related both to its detection scope, and to its response time. To assess the performance of such networks, two statistical indicators are therefore designed: the detection probability, computed on a large number of possible source locations, and the saturation time, which is the time when the maximum detection probability has been reached.Simulations are then carried out with the Polyphemus air quality modeling system for many emission scenarios, including 961 possible source locations, various emitted species, and a few representative meteorological situations. This allows to assess the performance of single sensors as well as full networks, and their sensitivity to parameters like meteorological conditions and source characteristics. The emitted quantity and meteorological dispersion are found to be important parameters, whereas the species type does not significantly influence the results. Two network design methods are considered: (1) networks composed of a given number of the “best” sensors according to an indicator, and (2) sensors placed in circles around the protected domain. The networks built with respect to the detection probability show good results with a limited number of sensors, while the saturation time is not reliable enough to build networks. The networks based on circles also show a good performance in the studied cases, provided there is a sufficient number of sensors. 相似文献
306.
Crispim Bdo A Vaini JO Grisolia AB Teixeira TZ Mussury RM Seno LO 《Environmental science and pollution research international》2012,19(3):718-723
Purpose
This study aimed to associate the intensity of vehicular traffic in the city of Dourados (Mato Grosso do Sul State, Brazil) with mutagenic effects and alterations in leaf physiology as measured by the quantity of micronuclei and the leaf surface parameters of Tradescantia pallida. 相似文献307.
Francisco Luiza Flavia Veiga do Amaral Crispim Bruno Spósito Juliana Caroline Vivian Solórzano Julio César Jut Maran Nayara Halimy Kummrow Fábio do Nascimento Valter Aragão Montagner Cassiana Carolina De Oliveira Kelly Mari Pires Barufatti Alexeia 《Environmental science and pollution research international》2019,26(24):24581-24594
Environmental Science and Pollution Research - Groundwaters are normally consumed without previous treatment and therefore the monitoring of contaminants in order to guarantee its safety is... 相似文献
308.
Bruno M. Esteves Carmen S. D. Rodrigues Luís M. Madeira 《Environmental science and pollution research international》2018,25(35):34826-34838
Degradation of total phenol (TPh) and organic matter, (expressed as total organic carbon TOC), of a simulated olive mill wastewater was evaluated by the Fenton oxidation process under batch and continuous mode conditions. A mixture of six phenolic acids usually found in these agro-industrial wastewaters was used for this purpose. The study focused on the optimization of key operational parameters of the Fenton process in a batch reactor, namely Fe2+ dosage, hydrogen peroxide concentration, pH, and reaction temperature. On the assessment of the process efficiency, > 99% of TPh and > 56% of TOC removal were attained when [Fe2+] = 100 ppm, [H2O2] = 2.0 g/L, T = 30 °C, and initial pH = 5.0, after 300 min of reaction. Under those operational conditions, experiments on a continuous stirred-tank reactor (CSTR) were performed for different space-time values (τ). TOC and TPh removals of 47.5 and 96.9%, respectively, were reached at steady-state (for τ = 120 min). High removal of COD (> 75%) and BOD5 (> 70%) was achieved for both batch and CSTR optimum conditions; analysis of the BOD5/COD ratio also revealed an increase in the effluent’s biodegradability. Despite the high removal of lumped parameters, the treated effluent did not met the Portuguese legal limits for direct discharge of wastewaters into water bodies, which indicates that coupled chemical-biological process may be the best solution for real olive mill wastewater treatment. 相似文献
309.
Alessandra De Bruno Rosa Romeo Francesca L. Fedele Andrea Sicari Amalia Piscopo Marco Poiana 《Journal of environmental science and health. Part. B》2018,53(8):526-533
In this study, the effects of experimental variables such as type of solvent, sample/solvent ratio, and time of extraction have been evaluated to individuate the best results in phenolic recovery by Olive Pomaces (OP) belonging to Carolea and Ottobratica cultivars. Folin–Ciocaulteu procedure and DPPH and ABTS assays were used, respectively, for total phenol quantification and total antioxidant activity of pomace extracts. The ethanol/water mixture was resulted the most efficient extraction solvent for both olive cultivars. The highest amount of phenolic compounds (171 ± 4 mg of gallic acid 100 g?1 of dry pomace) was obtained after extraction at 120 min with 2:1 solvent/OP (v/w) of Ottobratica Olive Pomace. The recovery of phenol compounds from olive wastes increases the sustainability of sector, allowing obtaining an extract that could be a suitable alternative in the food industry to the use of synthetic antioxidants in order to improve the quality of foods. 相似文献
310.
Environmental Economics and Policy Studies - This paper analyzes the price behavior of Phase III (2013–2020) EU-ETS emission allowances of CO2 by focusing on the dynamics of daily auction... 相似文献