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191.
The precautionary principle is increasingly discussed in debates over appropriate measures to address complex and uncertain risks. The principle has generally been defined as having two main components: preventive action in the face of uncertainty and reversing the burden of proof. In isolation, these two components would suggest that precaution is primarily reactive to potential problems rather than proactive. More recent statements have suggested that thorough assessment of alternatives is critical to the effective implementation of the precautionary principle. Alternatives assessment—also referred to as options analysis and facility planning—redirects environmental science and policy debates from characterizing problems to identifying solutions. In this commentary, we examine the rationale for a focus on alternatives assessment in implementing the precautionary principle. We examine methods and examples of alternatives assessment, as well as opportunities for the principle's integration in environmental policy. We argue that a greater focus on alternatives assessment can enhance the ability of decision makers to make truly precautionary decisions, stimulate innovation toward sustainable production, and more effectively place burdens on to those creating risks. Such a focus forms an essential component of a shift from “problem-based” environmental policy to “solutions-based” policy. This shift requires adequate research resources, tools, and a government commitment to a new paradigm of environmental protection. We conclude that we will only reach the goal of sustainable production if we change our environmental protection focus from figuring out how bad the situation will be to seeking alternatives to problematic activities and designing the conditions for a more sustainable future. 相似文献
192.
Biesmeijer JC Giurfa M Koedam D Potts SG Joel DM Dafni A 《Die Naturwissenschaften》2005,92(9):444-450
Several recent hypotheses, including sensory drive and sensory exploitation, suggest that receiver biases may drive selection
of biological signals in the context of sexual selection. Here we suggest that a similar mechanism may have led to convergence
of patterns in flowers, stingless bee nest entrances, and pitchers of insectivorous plants. A survey of these non-related
visual stimuli shows that they share features such as stripes, dark centre, and peripheral dots. Next, we experimentally show
that in stingless bees the close-up approach to a flower is guided by dark centre preference. Moreover, in the approach towards
their nest entrance, they have a spontaneous preference for entrance patterns containing a dark centre and disrupted ornamentation.
Together with existing empirical evidence on the honeybee's and other insects’ orientation to flowers, this suggests that
the signal receivers of the natural patterns we examined, mainly Hymenoptera, have spontaneous preferences for radiating stripes,
dark centres, and peripheral dots. These receiver biases may have evolved in other behavioural contexts in the ancestors of
Hymenoptera, but our findings suggest that they have triggered the convergent evolution of visual stimuli in floral guides,
stingless bee nest entrances, and insectivorous pitchers. 相似文献
193.
194.
Michael Simone-Finstrom Joel Gardner Marla Spivak 《Behavioral ecology and sociobiology》2010,64(10):1609-1617
Honeybees harvest and use plant resins in a mixture called propolis to seal cracks and smooth surfaces in the nest architecture.
Resins in the nest may be important in maintaining a healthy colony due to their antimicrobial properties. This study had
two main objectives: (1) Provide initial insight on the learning capabilities of resin foraging honeybees; (2) analyze the
sensitivity of resin foraging honeybees to tactile stimuli to elucidate its possible role as a mechanism behind resin foraging.
The first objective provides insight into the phenotype of these bees as compared to other forager types, while the second
creates a starting point for further work on behavioral mechanisms of resin foraging. Using tactile proboscis extension response
conditioning, we found that resin foragers learned to associate two different tactile stimuli, the presence of a gap between
two plates and a rough sandpaper surface, with a sucrose reward significantly better than pollen foragers. The results of
differential tactile conditioning exhibited no significant difference in the ability of resin foragers to discriminate between
smooth and rough surfaces as compared to pollen foragers. We also determined that the sucrose response thresholds (SRTs) of
returning resin foragers were lower compared to returning pollen foragers, but both resin foragers and pollen foragers learned
a floral odor equally well. This is the first study to examine SRTs and conditioning to tactile and olfactory stimuli with
resin foraging honeybees. The results provide new information and identify areas for future research on resin collectors,
an understudied foraging phenotype. 相似文献
195.
Om Prakash Stefan J. Green Pooja Singh Puja Jasrotia Joel E. Kostka 《Frontiers of Environmental Science & Engineering》2021,15(2):23
196.
David Eilam Pazit Zadicario Tom Genossar Joel Mort 《Behavioral ecology and sociobiology》2012,66(6):959-968
Social animals behave collectively in order to maintain a cohesive group. This collective behavior is often led by a few individuals of specific gender, social rank, or spatial physical location in the group (i.e., perimeter or front). We examined how individual social voles (Microtus socialis) in same-gender compared with mixed-gender groups respond to an owl attack. We found that anxiety level, as measured by the time that each individual spent in less-sheltered sectors (open arms of elevated plus-maze and center of open arena), was affected by both the social context and the gender of the tested individuals. While both female and male voles generally reduced their activity in the open following owl attack, males in mixed-gender groups were exceptional in dichotomizing into those that spent a short period and those that spent a long period in the open arms of the plus-maze. Based on the similar responses of the same-gender groups, we suggest that anxiety is contagious, and based on the lower anxiety level of the mixed-gender groups, we suggest that natural groups that comprise both males and females are better able to cope with life-threat compared with same-gender groups. Finally, we suggest that the differential responses of males in the mixed-gender groups were due to a few males that displayed a low level of anxiety. These males were probably individuals of high social rank, and their response reflects their natural protective role, as previously described in social voles. 相似文献
197.
Algal populations, either suspended in the water column (planktonic) or present on the walls of an enclosure (periphytic), develop differently depending upon the physical scale of the system. This study determined whether these variations altered the speciation and therefore exposure of polychlorinated biphenyls (PCBs) in estuarine mesocosms. Exposure was defined as the fraction of applied contaminant taken up by plankton after two hours. Using a three phase equilibrium model, the partitioning of a suite of PCBs within variously-sized mesocosms was predicted using laboratory derived distribution coefficients and measured levels of planktonic and periphytic algal biomass. in mesocosms having large wall surface area to volume ratios, sorption of hydrophobic PCBs to periphyton significantly decreased contaminant exposure. However, within the range of planktonic algal biomasses observed in this study, the regulation of PCB exposure was relatively invariant between variously-sized mesocosms. to minimize sorption of hydrophobic organic contaminants (HOCs) to periphyton and reduce artefacts inherent with this partitioning, we suggest using mesocosms with low wall surface area to volume ratios (less than or equal to 1). in addition, periphytic biomass should be quantified regularly and a three-phase equilibrium approach used to predict the actual exposure concentrations. 相似文献
198.
Jean Rouchaud Fabrice Gustin Frans van de Steene Christian Pelerents Luc Vanparys Joel Gillet 《毒物与环境化学》2013,95(1-2):79-94
In several field assays made in different locations in 1988 and 1989, cauliflower and Brussels sprouts plants were treated some days after plantation by pouring onto soil around the stem of the plant one of the insecticides chlorpyrifos, chlorfenvinphos, carbofuran, carbosulfan, or furathiocarb, for protection against the root fly. During plant growth, each of the insecticides (and their soil metabolites) was transported from soil into the plant foliage, where it could give—during a certain period of time—a secondary plant protection against the foliage insects. The foliage concentrations of the non systemic chlorpyrifos and chlorfenvinphos were equal or greater than 1 mg/kg fresh weight during a period of about 44 days after soil treatment in Brussels sprouts crops, and 35 days in cauliflower crops. Comparison of 1988 and 1989 however showed that these periods of time changed according to the weather conditions, especially rainfall. These periods of time were greater when the insecticide soil concentrations were greater—and thus when the rates of insecticide soil metabolism were smaller— and when the rainfall were greater—water transporting the insecticides from soil to the foliage. Similar relationships were observed with the systemic insecticides carbofuran, carbosulfan and furathiocarb; the weights per plant of insecticide compounds transported from soil into the foliage however were greater with these systemic insecticides than they were with the non systemic chlorpyrifos and chlorfenvinphos. The extreme values observed for the periods of time of insecticide foliage concentrations equal or greater than 1 mg/kg fresh weight thus were: 1. in cauliflower crops: 21 to 36 days for chlorpyrifos, and 23 to 39 days for chlorpyrifos + oxon; 24 to 37 days for chlorfenvinphos; 20 to 48 days for carbofuran; 2. in Brussels sprouts crops: 43 to 49 days for chlorpyrifos; 47 to 53 days for chlorpyrifos + oxon; 41 to 45 days for chlorfenvinphos; between 2 to 3 months for carbofuran, carbofuran + carbosulfan, and carbofuran + furathiocarb in the fields treated respectively with either carbofuran, carbosulfan, or furathiocarb. Moreover, in the spring and summer cauliflower crops made on fields onto which continuous cauliflower crops—with their soil insecticide treatments—had been made since a greater number of years (greater soil “history”), the insecticide compounds soil and foliage concentrations generally were lower. 相似文献
199.
Implementation of policy involves multiple agencies operating at multiple levels in facilitating processes and actions to accomplish desired results. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) was developed and implemented to regulate and control international wildlife trade, but violations of the agreement are widespread and growing worldwide, including in Nepal. This study attempts to understand how domestic CITES policies are translated into action and what effect actions and processes have on compliance. In doing so, this study provides insights into the implementation and enforcement pitfalls of national legislation that explain CITES violations in Nepal. Primarily, we used 26 key informants interviews to learn opinions of experts, and the grounded theory approach for further qualitative data analysis. In addition, we used Najman's (1995) policy implementation analysis framework to explain gaps. Many interrelated variables in the content of the policy, commitment and capacity of the agencies, the roles of clients and coalitions and contextual issues were observed. Variables that emerged suggest pitfalls in the regulatory policy represented by low probability of detection, arrest and punishment. Moreover, redistributive policies in buffer zones of protected areas are needed into perpetuity to benefit locals. Also, conservation organizations' support for building public and political salience is imperative. 相似文献
200.
For nearly two decades, the Yeast Estrogen Screen (YES) has been used as a valuable tool for determining the total estrogenic potency of various environmental samples, including influent and effluent streams at municipal wastewater plants. However, applying the YES assay to wastewater sludges and stabilized biosolids has been problematic. This is due to co-extracted compounds from the solids either proving toxic to the yeast or masking the presence of estrogenic substances. The present research describes the development and validation of sample preparation steps that mitigate the toxicity effects of municipal wastewater sludge and biosolid samples in the YES assay, while allowing for reliable dose-dependent expression of estrogenic activity. A copper work-up for sulfur removal and chromatographic cleanup with silica and alumina were required in addition to solid-phase extraction to adequately remove interfering compounds. Sample stabilization methods such as autoclaving, lyophilization and formaldehyde treatment were found to be detrimental to the assay. Hence, heat-drying is recommended to prevent cytotoxicity and the degradation of estrogenic substances. 相似文献