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461.
Hanna Eriksson H?gg Steve W. Lyon Teresia W?llstedt Carl-Magnus M?rth Bj?rn Claremar Christoph Humborg 《Ambio》2014,43(3):337-351
Dynamic model simulations of the future climate and projections of future lifestyles within the Baltic Sea Drainage Basin (BSDB) were considered in this study to estimate potential trends in future nutrient loads to the Baltic Sea. Total nitrogen and total phosphorus loads were estimated using a simple proxy based only on human population (to account for nutrient sources) and stream discharges (to account for nutrient transport). This population-discharge proxy provided a good estimate for nutrient loads across the seven sub-basins of the BSDB considered. All climate scenarios considered here produced increased nutrient loads to the Baltic Sea over the next 100 years. There was variation between the climate scenarios such that sub-basin and regional differences were seen in future nutrient runoff depending on the climate model and scenario considered. Regardless, the results of this study indicate that changes in lifestyle brought about through shifts in consumption and population potentially overshadow the climate effects on future nutrient runoff for the entire BSDB. Regionally, however, lifestyle changes appear relatively more important in the southern regions of the BSDB while climatic changes appear more important in the northern regions with regards to future increases in nutrient loads. From a whole-ecosystem management perspective of the BSDB, this implies that implementation of improved and targeted management practices can still bring about improved conditions in the Baltic Sea in the face of a warmer and wetter future climate. 相似文献
462.
Managing Manure from China’s Pigs and Poultry: The Influence of Ecological Rationality 总被引:1,自引:0,他引:1
We have investigated manure management practices at three farm scales in Chinese pig and poultry production. The concept of ecological rationality was employed to explore empirically how environmental concerns drive adoption of environmental-friendly manure management technologies at different farm scales. The more developed Rudong County in Jiangsu Province and the less developed Zhongjiang County in Sichuan Province were chosen as cases for study of 258 animal breeders. On the contrary to our hypothesis, medium-scale farmers were not always found to be laggards in adoption of manure management technologies. Government ecological rationality played a key role to induce environmental-friendly technology adoption on its own, but also in cooperation with ecologically rational individual or network drivers. Authorities no longer applied their efforts in a conventional command-and-control way, but more in the form of incentives, stimulation, and information to farmers. Individual farmers in general showed low environmental responsibility in relation to manure handling. 相似文献
463.
Coastal development has severely affected habitats and biodiversity during the last century, but quantitative estimates of the impacts are usually lacking. We utilize predictive habitat modeling and mapping of human pressures to estimate the cumulative long-term effects of coastal development in relation to fish habitats. Based on aerial photographs since the 1960s, shoreline development rates were estimated in the Stockholm archipelago in the Baltic Sea. By combining shoreline development rates with spatial predictions of fish reproduction habitats, we estimated annual habitat degradation rates for three of the most common coastal fish species, northern pike (Esox lucius), Eurasian perch (Perca fluviatilis) and roach (Rutilus rutilus). The results showed that shoreline constructions were concentrated to the reproduction habitats of these species. The estimated degradation rates, where a degraded habitat was defined as having ≥3 constructions per 100 m shoreline, were on average 0.5 % of available habitats per year and about 1 % in areas close to larger population centers. Approximately 40 % of available habitats were already degraded in 2005. These results provide an example of how many small construction projects over time may have a vast impact on coastal fish populations.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-014-0522-y) contains supplementary material, which is available to authorized users. 相似文献464.
Sustainable development requires that per capita inclusive wealth—produced, human, and natural capital—does not decline over time. We investigate the impact of changes in nitrogen on inclusive wealth. There are two sides to the nitrogen problem. Excess use of nitrogen in some places gives rise to N-pollution, which can cause environmental damage. Insufficient replacement of nitrogen in other places gives rise to N-depletion, or loss of nutrient stocks. Neither is explicitly accounted for in current wealth measures, but both affect wealth. We calculate an index of net N-replacement, and investigate its relationship to wealth. In countries with low levels of relative N-loss, we find that the uncompensated loss of soil nitrogen in poorer countries is associated with declining rates of growth of inclusive per capita wealth. What is less intuitive is that increasing fertilizer application in both rich and poor countries can increase per capita inclusive wealth. 相似文献
465.
Nutrient and dissolved inorganic carbon are two important factors that influence the development and species composition of submerged macrophyte communities in shallow lake ecosystems. Yet little is known about their potential interactive effects on the submerged macrophytes and competition outcome of macrophyte–phytoplankton. We performed a mesocosm experiment to investigate the growth and photosynthetic performance of three submerged macrophytes in relation to phytoplankton/epiphyton with nutrient and bicarbonate enrichment. During the experimental period (42 d), increase in nutrient loading in water column resulted in a substantial burst of phytoplankton and epiphyton growth and increased light attenuation. When combined with nutrient loading, bicarbonate enrichment also resulted in a heavily phytoplankton- and epiphyton-dominated state, although bicarbonate enrichment per se does not cause the phytoplankton and epiphyton growth. However, increase in nutrient loading in water column had significant negative impact on individual performances (growth and photosynthesis) of the three submerged macrophytes and bicarbonate enrichment increased the effect of eutrophication on two dissected-leaf macrophytes (M. spicatum and E. nuttallii). Furthermore, our results also suggest that species-specific photosynthetic performances occurred when submerged macrophytes in an environment with high abundance of phytoplankton/epiphyton. This study highlighted that increase in nutrient loading and bicarbonate in water column is likely to interactively impact both abiotic and biotic properties of a freshwater ecosystem. The interactions of these two factors could select macrophyte species that are able to resist the shading from phytoplankton/epiphyton, making these species more dominant in natural freshwater ecosystems. 相似文献
466.
湖南省水土流失及其危害 总被引:1,自引:0,他引:1
目前湖南省水土流失面积已由50a前的1.87万km2增加为4.40万km2,占全省土地总面积的20.8%。水土流失为中等以上的县市占全省的比例达到了60%。湖南省水土流失以面蚀为主,水土流失日趋严重。水土流失主要有以下危害降低土壤肥力,加剧旱洪灾害尤其是湖区的洪涝灾害,降低水利工程效益和阻碍水上交通。由此可见,水土保持工作不仅关系到湖南山区的经济发展和广大山区人民的脱贫致富,还关系到保护环境、资源和洞庭湖区的长治久安问题。 相似文献
467.
468.
Georgios K. Sylaios Vassilios A. Tsihrintzis 《Environmental Modeling and Assessment》2009,14(1):59-72
The nutrient dynamics of the Strymonikos and Ierissos Gulfs, two semienclosed coastal water bodies, are studied using a simple
steady-state budget model, according to the Land–Ocean Interaction in the Coastal Zone modeling guidelines. Strymon river
plume dynamics prevailed in the area of the Inner and Outer Srymonikos Gulfs, comprising two layers, while the Ierissos Gulf
was defined as a one-box system. Seasonal and mean annual model input data for river discharge, precipitation, evaporation,
and concentrations of salt, phosphorus, and nitrogen were obtained during four field campaigns. Results from the nitrogen
and phosphorus cycling revealed the importance of river discharge in the horizontal and vertical transport of these substances
within the system. Furthermore, it occurred that the major biogeochemical transformation of nitrogen and phosphorus takes
place in the immediate nearshore zone (Inner Strymonikos Gulf), while the outer system sustains its nutrient dependence on
oceanic exchanges. Therefore, under the summer low flow conditions, the river-influenced inner system acts as a net source
of nitrogen and phosphorus, while under increased Strymon River discharge, phosphorus is transferred to the biological material
(and the sediments), and the system moves to an autotrophic state. The outer system showed an opposite behavior being autotrophic
throughout the year and heterotrophic in February. The Ierissos Gulf, a system not directly influenced by significant river
discharge, experienced a seasonally independent behavior with net heterotrophic and denitrification processes prevailing.
Model scenarios demonstrated that phosphate concentration increases, even under low river flow conditions and stimulates primary
production in excess of respiration, resulting in nitrogen fixation prevalence in the Inner Strymonikos Gulf. 相似文献
469.
470.
于2016年在中国广东大气超级监测站,开展4个季节的VOCs长时间观测,共获得2142组有效数据,并利用HYSPLIT模型分析珠三角地区VOCs时空分布特征.结果表明,各类VOCs混合比和化学反应活性具有明显的季节变化特点.观测期间,VOCs平均浓度为(18.523±20.978)×10-9,其中,低碳烯烃和苯系物二者混合比之和仅占46%,但贡献了85%的·OH消耗速率(LOH)、82%的臭氧生成潜势(OFP)和97%的二次气溶胶生成潜势(SOAFP).观测站点主要受来自北部内陆地区气团(1#)、西部内陆地区气团(2#)、台湾海峡南端气团(3#)以及南部海洋地区气团(4#)的影响.1#气团中炔烃和苯系物的混合比占比最高,分别达到10%、37%,而3#气团中低碳烷烃的浓度水平最高,达到(8.437±5.561)×10-9.通过估算气团中VOCs的化学反应活性,可以发现,1#气团的VOCs化学反应活性最强,其对O3和SOA的生成贡献最高.1#、2#、3#和4#气团中VOCs的化学反应活性主要由苯系物和低碳烯烃贡献. 相似文献