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261.
V. Rivas A. González D. W. Fischer A. Cendrero 《Journal of Environmental Planning and Management》1994,37(3):305-322
The problems involved in environmental assessment of land‐use plans are discussed. A methodology is proposed for incorporating into the assessment of a plan the modifications that the physical environment would experience as a result of the plan's implementation. Thus, EIA can be integrated into the planning process. Impact assessment and comparison between alternative plans can be made using quantitative and qualitative indicators, some of which are proposed. Several case studies in northern Spain are used as the basis for the suggestions made. 相似文献
262.
Most animals can modulate nutrient storage pathways according to changing environmental conditions, but in honey bees nutrient storage is also modulated according to changing behavioral tasks within a colony. Specifically, bees involved in brood care (nurses) have higher lipid stores in their abdominal fat bodies than forager bees. Pheromone communication plays an important role in regulating honey bee behavior and physiology. In particular, queen mandibular pheromone (QMP) slows the transition from nursing to foraging. We tested the effects of QMP exposure on starvation resistance, lipid storage, and gene expression in the fat bodies of worker bees. We found that indeed QMP-treated bees survived much longer compared to control bees when starved and also had higher lipid levels. Expression of vitellogenin RNA, which encodes a yolk protein that is found at higher levels in nurses than foragers, was also higher in the fat bodies of QMP-treated bees. No differences were observed in expression of genes involved in insulin signaling pathways, which are associated with nutrient storage and metabolism in a variety of species; thus, other mechanisms may be involved in increasing the lipid stores. These studies demonstrate that pheromone exposure can modify nutrient storage pathways and fat body gene expression in honey bees and suggest that chemical communication and social interactions play an important role in altering metabolic pathways. 相似文献
263.
It is frequently assumed that males have an almost unlimited reproductive capacity, while access to receptive females is typically
limiting. Consequently, sexual selection is expected to favor vigorous courtship behavior in males. If such behavior is associated
with non-trivial costs, ample current mating opportunities should be accompanied by a reduction in future mating vigor. To
test this hypothesis, three treatments differing in sex ratio were established using the tropical butterfly Bicyclus anynana: 50 males each were housed either with 0, 25, or 50 females. Mating trials involving the competition among males from each
treatment for a single virgin female were carried out on days 3, 9, and 15 after allocation to treatments. While there was
no difference on day 3, prior mating opportunity clearly reduced mating success on days 9 and 15, being lowest if identical
numbers of males and females were housed together. This finding suggests accumulating costs associated with high courtship
and/or mating activity. Further, older males were more active and initiated copulation earlier than the younger ones, consistent
with the residual reproductive value hypothesis. We found no evidence for a survival or fertility cost of mating. 相似文献
264.
Males frequently mate multiply, but are there negative fitness consequences for their later mates? Potential costs include less sperm and less nutrition. In most hymenopterans, daughters, but not sons, are produced sexually. This mean that effects of being a later mate on sperm received versus on nutrients received should be distinguishable. If later mates receive less sperm, it should manifest as a reduction in daughter production, whereas a reduction in nutrients should affect production of both sexes. Any cost to being a later mate may in turn select for polyandry or for female choice of virgin males. Males of the parasitoid wasp Spalangia endius were presented with up to five females in succession. Offspring production was compared among first, third, and fifth females; and it did not differ. However, about half of fifth females had begun producing only sons by their tenth day, whereas first and third females rarely had. Despite the reduction in daughter production, even fifth females rarely remated. However, females tended to mate with virgin males rather than mated males when given a choice. This tendency was dependent on male, not female, behavior, but should benefit the female nevertheless. Sex ratios in this species are one male for every one and a half to three females. Thus, the number of times that males could mate before daughter production was reduced coincided roughly with the mean number of times that males likely mate in this species. Nevertheless, some females are likely to experience the cost of being a fifth female because of skewed mating success among males. 相似文献
265.
Karla Ili&cacute &Dstrok ur&dstrok i&cacute Raluca Ostafe Olivera Prodanovi&cacute Aleksandra &Dstrok ur&dstrok evi&cacute &Dstrok elma Nikolina Popovi&cacute Rainer Fischer Stefan Schillberg Radivoje Prodanovi&cacute 《Frontiers of Environmental Science & Engineering》2021,15(2):19
266.
Tolera Senbeto Jiren Maraja Riechers Ruth Kansky Joern Fischer 《Conservation biology》2021,35(6):1957-1965
Fostering human–wildlife coexistence requires transdisciplinary approaches that integrate multiple sectors, account for complexity and uncertainty, and ensure stakeholder participation. One such approach is participatory scenario planning, but to date, this approach has not been used in human–wildlife contexts. We devised a template for how participatory scenario planning can be applied to identify potential avenues for improving human–wildlife coexistence. We drew on 3 conceptual building blocks, namely the SEEDS framework, the notion of critical uncertainties, and the three-horizons technique. To illustrate the application of the proposed template, we conducted a case study in the Zambezi region of Namibia. We held 5 multistakeholder workshops that involved local people as well as numerous nongovernment and government stakeholders. We identified 14 important wildlife species that generated multiple services and disservices. The subsequent benefits and burdens, in turn, were inequitably distributed among stakeholders. Government actors played particularly influential roles in shaping social-ecological outcomes. We identified 2 critical uncertainties for the future: the nature of governance (fragmented vs. collaborative) and the type of wildlife economy (hunting vs. photography based). Considering these uncertainties resulted in 4 plausible scenarios describing future human–wildlife coexistence. Stakeholders did not agree on a single preferred scenario, but nevertheless agreed on several high-priority strategies. Bridging the remaining gaps among actors will require ongoing deliberation among stakeholders. Navigating the complex challenges posed by living with wildlife requires moving beyond disciplinary approaches. To that end, our template could prove useful in many landscapes around the world. 相似文献
267.
268.
Plant-soil microorganism interactions: heritable relationship between plant genotype and associated soil microorganisms 总被引:3,自引:0,他引:3
Schweitzer JA Bailey JK Fischer DG LeRoy CJ Lonsdorf EV Whitham TG Hart SC 《Ecology》2008,89(3):773-781
Although soil microbial communities are known to play crucial roles in the cycling of nutrients in forest ecosystems and can vary by plant species, how microorganisms respond to the subtle gradients of plant genetic variation is just beginning to be appreciated. Using a model Populus system in a common garden with replicated clones of known genotypes, we evaluated microbial biomass and community composition as quantitative traits. Two main patterns emerged. (1) Plant genotype influenced microbial biomass nitrogen in soils under replicated genotypes of Populus angustifolia, F1, and backcross hybrids, but not P. fremontii. Genotype explained up to 78% of the variation in microbial biomass as indicated by broad-sense heritability estimates (i.e., clonal repeatability). A second estimate of microbial biomass (total phospholipid fatty acid) was more conservative and showed significant genotype effects in P. angustifolia and backcross hybrids. (2) Plant genotype significantly influenced microbial community composition, explaining up to 70% of the variation in community composition within P. angustifolia genotypes alone. These findings suggest that variation in above- and belowground traits of individual plant genotypes can alter soil microbial dynamics, and suggests that further investigations of the evolutionary implications of genetic feedbacks are warranted. 相似文献
269.
Richard N. Koustas David Fischer 《Journal of the Air & Waste Management Association (1995)》2013,63(5):434-440
ABSTRACT Pesticide contamination results from manufacturing, improper storage, handling, or disposal of pesticides, and from agricultural processes. Since most pesticides are mixtures of different compounds, selecting a remedy for pesticide-contaminated soils can be a complicated process. The various available treatment options for remediation fall into three broad categories: containment-immobilization, separation-concentration, and destruction. This paper categorizes pesticides into waste groups based on available treatment options and provides a review of separation treatment options that have been demonstrated to—or show potential to— treat pesticide-contaminated soil. Technologies include radio frequency heating, soil washing, thermal desorp-tion, and solvent extraction. 相似文献
270.
The current lack of a working resource management plan Magdalena Bay (southern Baja California, Mexico) has weakened attempts
to set priorities among resource users and has contributed to: reduced fish stocks, land and marine contamination, and declines
in the ecological integrity of the bay of 170 000 ha and its vast mangrove lagoon systems. The government agencies responsible
for maintaining ecological integrity and managing marine resource use have not been successful in addressing these problems
due to jurisdictional ambiguities, lack of community support, and lack of manpower for monitoring and enforcing policies.
A framework was designed by the authors to work toward an approach for balancing between community development and conserving
ecological integrity at the local level in the peripheral and central zones of the Magdalena Bay system. The goal of this
framework was to suggest a basis for setting management priorities that included the perceptions and preferences of stakeholder
groups with regard to direct threats to the environmental health of the study areas. To achieve this goal a crossdisciplinary
study of the central and peripheral zones was used to examine factors that influence current resource use and the environmental
state in these two regions of the bay system. Insights into the preferences and perceptions of stakeholder groups with regard
to management priorities were acquired using the key informant technique. The results revealed potential conflicts with regard
to preferred management priorities between stakeholder groups, as well as polarities within stakeholder groups themselves. 相似文献