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991.
Wolfgang Priester (1924–2005) was one of Germany’s most versatile and quixotic astrophysicists, reinventing himself successively
as a radio astronomer, space physicist and cosmologist, and making a lasting impact on each field. We focus in this personal
account on his contributions to cosmology, where he will be most remembered for his association with quasars, his promotion
of the idea of a nonsingular “big bounce” at the beginning of the current expansionary phase, and his recognition of the importance
of dark energy (Einstein’s cosmological constant Λ) well before this became the standard paradigm in cosmology.
In memoriam Wolfgang Priester, 22 April 1924 – 9 July 2005 相似文献
992.
Alain Dejean Bruno Corbara Frédéric Azémar James M. Carpenter 《Die Naturwissenschaften》2012,99(7):579-582
Because group-hunting arboreal ants spread-eagle insect prey for a long time before retrieving them, these prey can be coveted by predatory flying insects. Yet, attempting to rob these prey is risky if the ant species is also an effective predator. Here, we show that trying to rob prey from Azteca andreae workers is a fatal error as 268 out of 276 potential cleptobionts (97.1?%) were captured in turn. The ant workers hunt in a group and use the “Velcro?” principle to cling firmly to the leaves of their host tree, permitting them to capture very large prey. Exceptions were one social wasp, plus some Trigona spp. workers and flies that landed directly on the prey and were able to take off immediately when attacked. We conclude that in this situation, previously captured prey attract potential cleptobionts that are captured in turn in most of the cases. 相似文献
993.
Alebel Abebe Belay Henry Musoke Semakula George James Wambura Labohy Jan 《中国人口.资源与环境(英文版)》2013,11(1):8-17
Abstract River Nile is one of the longest transboundery rivers and it is shared and used by Burundi, Democratic Republic of Congo, Egypt, Ethiopia, Eritrea, Kenya, Rwanda, Sudan, Tanzania and Uganda. As of today, the Nile is a crucial resource for the economic development of the Nile Basin countries and a vital source of livelihood for 160 million inhabitants as well as 300 million people living in the 10 riparian countries. The Nile Basin Initiative (NBI) is one of the international cooperative river basin management program and regional partnership where all the Nile Basin countries except Eritrea unite to pursue long-term sustainable development, improved land use practices and management. This review therefore focused on the challenges not faced on NBI in terms of integrated use of the river and conducted analysis of strengths, weaknesses, opportunities and threats (SWOT) based on secondary data. The result of the review revealed that for decades, the Nile Basin people have been facing many complex environmental, social, economic and political challenges that have made it difficult for the proper management and sustainability of Nile water. The initiative provides training to develop skills in government ministries, non-governmental organizations and local communities in each country. It is also working to raise awareness of critical environmental issues by strengthening networks of environmental education practitioners; developing curriculum in the education sector. The challenges of NBI include the involvement and funding of World Bank, lack of sufficient staff, procedural and policies conflicts, lack of coordination and linkage with other regional institutions and lack of recognition as river basin organization. Considering the complex nature of the project, it is recommended that the NBI should come up with a strong multi-disciplinary monitoring and evaluation team to follow up all implemented projects. The NBI should carry out participatory land use planning in communities along the river basin. Moreover, livelihood analysis should be carried out especially in communities along the Nile to come up with poverty eradication projects which are socially acceptable, applicable, economically viable and affordable. 相似文献
994.
Edward?A.?RoualdesEmail authorView authors OrcID profile
return OK on get Simon?J.?Bonner Thomas?D.?Whitney James?D.?Harwood 《Environmental and Ecological Statistics》2016,23(2):317-336
The literature on modelling a predator’s prey selection describes many intuitive indices, few of which have both reasonable statistical justification and tractable asymptotic properties. Here, we provide a simple model that meets both of these criteria, while extending previous work to include an array of data from multiple species and time points. Further, we apply the expectation–maximisation algorithm to compute estimates if exact counts of the number of prey species eaten in a particular time period are not observed. We conduct a simulation study to demonstrate the accuracy of our method, and illustrate the utility of the approach for field analysis of predation using a real data set, collected on wolf spiders using molecular gut-content analysis. 相似文献
995.
Schliep Erin M. Gelfand Alan E. Clark James S. Zhu Kai 《Environmental and Ecological Statistics》2016,23(1):23-41
Environmental and Ecological Statistics - Predictions of above-ground biomass and the change in above-ground biomass require attachment of uncertainty due the range of reported predictions for... 相似文献
996.
997.
Since the Brundtland Commission's delineation of the term sustainable development in 1987, virtually every country has incorporated the terms sustainability and sustainable development into their planning vocabulary and criteria for decision-making. However, many issues remain unresolved. Broad and sweeping references to sustainability and sustainable development do not necessarily translate into implementable policies to achieve these goals. In particular, unresolved issues include developing an understanding of how one sector of the economy can contribute to the sustainable development of the economy as a whole and the role of ecological resources in sustainable development. Our paper provides an initial conceptual examination of these questions by folding mining and ecological quality into the sustainability discussion. We use the Brazilian Amazon as an application of our sustainable development model. 相似文献
998.
Zoanthids of the order Zoantharia (Anthozoa: Hexacorallia) exhibit high intraspecific morphological variability, but whether this is due to polymorphism, phenotypic plasticity or a combination of both remains unknown. To address this knowledge gap, in November 2010, eight colonies each of Zoanthus sansibaricus and Palythoa tuberculosa were sampled from three reefs off the south of mainland Singapore and transplanted to a shallow experimental site. The colonies were then distributed under two types of treatment frames: control and shaded. After 87 days, morphometric characters were extracted from macro-images. Reaction norms, principal components analysis, analysis of variance and canonical discriminant analysis all demonstrated light-induced changes in morphology. Patterns of plastic changes were similar for both species: shaded colonies had larger polyps as compared to control colonies. The presence of plastic responses in zoanthids may facilitate their colonization of a broad range of habitats as well as help them to withstand temporal changes in their environment. 相似文献
999.
Kathrine G. Howard Jeremy T. Claisse Timothy B. Clark Kelly Boyle James D. Parrish 《Marine Biology》2013,160(7):1583-1595
The activity and movement of the Redlip Parrotfish, Scarus rubroviolaceus, near Wawaloli reef, Hawaii (19°43′06″N, 156°03′11″W), was investigated with active and passive tracking techniques from April through November 2007. Site fidelity was determined and home range sizes were measured for 21 individuals. All individuals showed strong diurnal activity patterns and relatively stable home ranges. Terminal phase individuals had larger home range areas than initial phase fish, and home range size increased with depth. Occasional long forays from the home range were observed in many individuals. Forays often occurred in crepuscular hours and may represent migrations to/from nocturnal sheltering sites. Findings from this study underscore the importance of depth and nighttime shelter migrations as design considerations for effective marine protected areas (MPA) for large parrotfishes. 相似文献
1000.
Shih-Houng Young Jean M. Cox-Ganser Elizabeth S. Shogren Michael G. Wolfarth Shengqiao Li James M. Antonini 《毒物与环境化学》2013,95(4):806-823
It is observed that 1?→?3-β-glucan, a major cell wall component of fungi, induces pulmonary inflammation. There is inconsistency in determining the correlation between the levels of glucan measured by current extraction methods and the respiratory inflammation observed in individuals or lab animals exposed to environmental dust samples. The glucan-specific limulus amebocyte lysate (G-LAL) method was used after extraction with dimethyl sulfoxide (DMSO) or sodium hydroxide (NaOH) to analyze the glucan content of office dust samples collected from a water-damaged building. C3HeB/FeJ mice, an endotoxin-sensitive strain, were treated with different dust samples (2.5?mg?kg?1 body weight) or saline (vehicle control) by pharyngeal aspiration. At 1?day after aspiration, bronchoalveolar lavage (BAL) was performed, and lung inflammation and injury were assessed by measuring: (1) neutrophil (PMN) infiltration, (2) inflammatory cytokine (IL-6, IL-10, MCP-1, IFN-γ, TNF-α, and IL12-p70) levels, and (3) albumin and lactate dehydrogenase in recovered BAL fluid. Both DMSO and NaOH extraction increased the detection of glucan by approximately 20-fold compared to water extraction. However, only the DMSO extraction method showed a statistically significant positive correlation between 1?→?3-β-glucan and albumin levels, total numbers of BAL, polymorphonuclear leukocytes (PMNs) cells recovered, levels of TNF-α, MCP-1, and IL-6. In conclusion, 1?→?3-β-glucan is a potent inflammatory agent in dust samples and DMSO extraction for glucan analysis may prove useful in understanding the impact of environmental contamination by glucans on lung disease. 相似文献