全文获取类型
收费全文 | 1308篇 |
免费 | 91篇 |
国内免费 | 481篇 |
专业分类
安全科学 | 120篇 |
废物处理 | 68篇 |
环保管理 | 130篇 |
综合类 | 807篇 |
基础理论 | 217篇 |
污染及防治 | 333篇 |
评价与监测 | 74篇 |
社会与环境 | 75篇 |
灾害及防治 | 56篇 |
出版年
2024年 | 9篇 |
2023年 | 21篇 |
2022年 | 76篇 |
2021年 | 70篇 |
2020年 | 67篇 |
2019年 | 51篇 |
2018年 | 61篇 |
2017年 | 61篇 |
2016年 | 87篇 |
2015年 | 81篇 |
2014年 | 116篇 |
2013年 | 130篇 |
2012年 | 119篇 |
2011年 | 120篇 |
2010年 | 111篇 |
2009年 | 91篇 |
2008年 | 85篇 |
2007年 | 90篇 |
2006年 | 74篇 |
2005年 | 49篇 |
2004年 | 37篇 |
2003年 | 41篇 |
2002年 | 36篇 |
2001年 | 39篇 |
2000年 | 22篇 |
1999年 | 30篇 |
1998年 | 16篇 |
1997年 | 21篇 |
1996年 | 13篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 15篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1984年 | 1篇 |
排序方式: 共有1880条查询结果,搜索用时 904 毫秒
411.
北美自由贸易区和欧盟的区域性环境政策浅析 总被引:1,自引:0,他引:1
环境因素逐渐成为影响全球和各国经济的重要因素,以北自由贸易区和欧盟为代表的区域性经济集团在环境态度及政策取向上已日趋一致,在对这2个区域性经济集团的环境制度性安排的特点进行分析后,探讨了在未来可持续增长模式下,世界环境政策发展的趋势;同时也分析了我国应积极采取的对策。 相似文献
412.
Mengsheng Qin Lu Hao Lei Sun Yongqiang Liu Ge Sun 《Journal of the American Water Resources Association》2019,55(1):189-208
Reference evapotranspiration (ETo) is an important hydrometeorological term widely used in understanding and projecting the hydrological effects of future climate and land use change. We conducted a case study in the Qinhuai River Basin that is dominated by a humid subtropical climate and mixed land uses in southern China. Long‐term (1961–2012) meteorological data were used to estimate ETo by the FAO‐56 Penman–Monteith model. The individual contribution from each meteorological variable to the trend of ETo was quantified. We found basin‐wide annual ETo decreased significantly (p < 0.05) by 3.82 mm/yr during 1961–1987, due to decreased wind speed, solar radiation, vapor pressure deficit (VPD), and increased relative humidity (RH). However, due to the increased VPD and decreased RH, the ETo increased significantly (p < 0.05) in spring, autumn, and annually at a rate of 2.55, 0.56, and 3.16 mm/yr during 1988–2012, respectively. The aerodynamic term was a dominant factor controlling ETo variation in both two periods. We concluded the key climatic controls on ETo have shifted as a result of global climate change during 1961–2012. The atmospheric demand, instead of air temperature alone, was a major control on ETo. Models for accurately predicting ETo and hydrological change under a changing climate must include VPD in the study region. The shifts of climatic control on the hydrological cycles should be considered in future water resource management in humid regions. 相似文献
413.
414.
以花背蟾蜍为研究对象,以包头市某尾矿库南侧受污染的水域湿地和相对无污染的小白河黄河湿地保护区为研究样地。对比分析雄性花背蟾蜍形态学指标、精巢脏器系数、精子动态参数、精子畸形率、性激素、红细胞微核率和DNA损伤等相关指标,研究重金属复合污染场地对花背蟾蜍雄性性腺的毒性效应。结果显示:与小白河湿地相比,尾矿库湿地花背蟾蜍条件因子和精巢脏器系数显著高于小白河湿地(P<0.01)。尾矿库花背蟾蜍精子的鞭打频率显著升高,而精子活力显著降低(P<0.05),精子畸形率、红细胞微核率和DNA损伤均显著高于小白河湿地(P<0.05)。结果表明:尾矿库复合污染通过降低精子质量,增加红细胞微核率和DNA损伤对花背蟾蜍的雄性性腺造成毒理学影响,花背蟾蜍通过升高条件因子和精巢脏器系数来缓解复合污染的毒性胁迫。该成果对重金属复合污染场地两栖类动物种群保护以及生态平衡维护有着积极作用。 相似文献
415.
《浙江省生态环境保护"十三五"规划》在改善全省生态环境质量方面发挥着重要的宏观引领作用。为查找规划实施薄弱环节、发现问题、提出建议,本研究采取定量评估与定性结合的方式,开展规划中期评估研究。结论表明:该规划的约束性指标和预期性指标均完成较好,"三大战役"进展明显,制度改革不断突破,"三大工程"扎实推进。针对管理制度、环境质量、基础能力等六方面的主要问题,提出了严格调度考核、打赢蓝天保卫战、实施碧水行动等八项对策建议。 相似文献
416.
Sila Onesmus Nzung Weizhi Pan Taiming Shen Wei Li Xiaoqun Qin Chenwei Wang Liankai Zhang Longjiang Yu 《环境科学学报(英文版)》2018,30(4):173-181
This study provides the presence of carbonic anhydrase(CA) activity in waters of the Yangtze River basin, China, as well as the correlation of CA activity with HCO-3 concentration and CO_2 sink flux. Different degrees of CA activity could be detected in almost all of the water samples from different geological eco-environments in all four seasons. The CA activity of water samples from karst areas was significantly higher than from non-karst areas(PP3-concentration(r = 0.672, P2 sink flux(r = 0.602, P = 0.076) in karst areas. This suggests that CA in waters might have a promoting effect on carbon sinks for atmospheric CO_2 in karst river basins. In conditions of similar geological type, higher CA activity was generally detected in water samples taken from areas that exhibited better eco-environments, implying that the CA activity index of waters could be used as an indicator for monitoring ecological environments and protection of river basins. These findings suggest that the role of CA in waters in the karst carbon sink potential of river basins is worthy of further in-depth studies. 相似文献
417.
Turbulent mixing is enhanced in shallow lakes. As a result, exchanges across the air–water and sediment–water interfaces are increased, causing these systems to be large sources of greenhouse gases. This study investigated the effects of turbulence on carbon dioxide(CO_2)and methane(CH_4) emissions in shallow lakes using simulated mesocosm experiments.Results demonstrated that turbulence increased CO_2 emissions, while simultaneously decreasing CH_4 emissions by altering microbial processes. Under turbulent conditions, a greater fraction of organic carbon was recycled as CO_2 instead of CH_4, potentially reducing the net global warming effect because of the lower global warming potential of CO_2 relative to CH_4. The CH_4/CO_2 flux ratio was approximately 0.006 under turbulent conditions, but reached 0.078 in the control. The real-time quantitative PCR analysis indicated that methanogen abundance decreased and methanotroph abundance increased under turbulent conditions, inhibiting CH_4 production and favoring the oxidation of CH_4 to CO2.These findings suggest that turbulence may play an important role in the global carbon cycle by limiting CH4 emissions, thereby reducing the net global warming effect of shallow lakes. 相似文献
418.
Perfluorooctanoic acid(PFOA)is recalcitrant to degrade and mineralize.Here,the effect of temperature on the photolytic decomposition of PFOA was investigated.The decomposition of PFOA was enhanced from 34% to 99% in 60 min of exposure when the temperature was increased from 25 to 85°C under UV light(201–600 nm).The limited degree of decomposition at 25°C was due to low quantum yield,which was increased by a factor of 12 at 85°C.Under the imposed conditions,the defluorination ratio increased from 8% at 25°C to 50% at85°C in 60 min.Production of perfluorinated carboxylic acids(PFCAs,C7–C5),PFCAs(C4–C3)and TFA(trifluoroacetic acid,C2)accelerated and attained a maximum within 30 to 90 min at 85°C.However,these reactions did not occur at 25°C despite extended irradiation to180 min.PFOA was decomposed in a step-wise process by surrendering one CF2unit.In each cyclical process,increased temperature enhanced the quantum yields of irradiation and reactions between water molecules and intermediates radicals.The energy consumption for removing eachμmol of PFOA was reduced from 82.5 k J at 25°C to 10.9 k J at 85°C using photolysis.Photolysis coupled with heat achieved high rates of PFOA degradation and defluorination. 相似文献
419.
420.
Juan Qin Chuanmeng Yang Chong Cui Jiantao Huang Ahmad Hussain Hailong Ma 《环境科学学报(英文版)》2016,28(9):91-99
Lime mud is a kind of solid waste in the papermaking industry, which has been a source of serious environmental pollution. Ceramsites containing anorthite and gehlenite were prepared from lime mud and fly ash through the solid state reaction method at 1050°C. The objective of this study was to explore the efficiency of Ca2 + and OH− release and assess the phosphorus and copper ion removal performance of the ceramsites via batch experiments, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that Ca2 + and OH− were released from the ceramsites due to the dissolution of anorthite, gehlenite and available lime. It is also concluded that gehlenite had stronger capacity for Ca2 + and OH− release compared with anorthite. The Ca2 + release could be fit well by the Avrami kinetic model. Increases of porosity, dosage and temperature were associated with increases in the concentrations of Ca2 + and OH− released. Under different conditions, the ceramsites could maintain aqueous solutions in alkaline conditions (pH = 9.3–10.9) and the release of Ca2 + was not affected. The removal rates of phosphorus and copper ions were as high as 96.88% and 96.81%, respectively. The final pH values of both phosphorus and copper ions solutions changed slightly. The reuse of lime mud in the form of ceramsites is an effective strategy. 相似文献