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711.
D301R树脂对铬(Ⅵ)的吸附性能研究 总被引:7,自引:0,他引:7
在pH=2.63的HAc-NaAc体系中,D301R树脂对Cr(Ⅵ)有较好的吸附性。树脂的静态饱和吸附容量为206mg/g。用 5%NH4CI和10%NH3·H2O的混合液能定量洗脱,测得吸附速率常数k298=2.52×10~(-4)/s。吸附过程遵守Freundlich等温式。298K 时测得吸附热力学参数△H=3.33kJ/mol、△G=-6.96kJ/mol、△S=34.5J/(mol·K)。树脂功能基与Cr(Ⅵ)的配位比为1:1。 相似文献
712.
疏水性有机物和有机酸碱溶解度的估算 总被引:1,自引:2,他引:1
本文从理论上建立了疏水性有机物和任意pH条件下有机酸碱溶解度的估算方法,并估算了不同类型有机物的溶解度,和实测值比较,结构和辛醇相近的有机物吻合较好;结构不同,则有一定的偏差,这是由于假设有机物在辛醇中的活度系物等于1所致。经校正后得到了较好的结果。 相似文献
713.
中国土壤科学发展的理论与实践 总被引:12,自引:3,他引:12
从土壤作为资源与环境共同载体这一角度出发,阐述了土壤科学发展的特点、土壤科学研究的特性和方向,提出了土壤“3P”、土壤“3S”和土壤“3R”的未来创新研究内容。认为应牢牢把握“土壤圈”这一现代土壤科学发展的理论基础,丰富和发展现代土壤科学,不断推进土壤科学发展与创新的实践运用。 相似文献
714.
715.
为了提高膨胀阻燃环氧体系的阻燃和抑烟效率,利用聚磷酸铵-季戊四醇-三聚氰胺为膨胀阻燃剂、有机蒙脱土(OMMT)和MoO3为复配协效剂制备了膨胀阻燃环氧树脂,通过极限氧指数(LOI)、UL94、锥形量热仪和烟密度试验研究了膨胀阻燃环氧树脂的阻燃和抑烟性能。结果表明,单独添加OMMT或MoO3均能有效提高膨胀阻燃环氧树脂的LOI并降低燃烧过程中的热释放和生烟量,将二者复配使用还表现出较好的协效作用。添加质量分数1.5%OMMT和1.5%MoO3时,膨胀阻燃氧树脂的LOI达到27.8%,UL94达到V-0级,总释放热(THR)和总产烟量(TSR)相比未添加协效剂的膨胀阻燃环氧树脂分别下降了49.5%和57.8%。热重分析表明,单独添加OMMT或MoO3均能有效提高膨胀阻燃EP的热稳定性和成炭率,二者复配使用则表现出更高的初始分解温度并形成更多的残炭量。扫描电镜和红外光谱分析发现,OMMT和MoO3复配使用能促进膨胀阻燃氧树脂在燃烧过程中形成更多的交联结构以增强炭层的致密性和隔热性能,达到协效阻燃和抑烟作用。 相似文献
716.
以SRB颗粒污泥为载体的硫酸盐型厌氧氨氧化的启动研究 总被引:1,自引:0,他引:1
采用复合式厌氧折流板反应器(HABR),研究先驯化硫酸盐还原菌(SRB)颗粒污泥、再以之为载体进行硫酸盐型厌氧氨氧化的启动,通过NH_4~+-N、SO_4~(2-)、COD等指标的变化探讨启动的效能。在7pH8.5、温度为(32±1)℃的条件下,采用低负荷启动方式,以CH_3COONa为有机碳源,通过逐步缩短HRT提高进水负荷来驯化培养硫酸盐还原菌颗粒污泥。结果表明,SO_4~(2-)与COD去除效果逐步达到稳定,最高去除率分别为86.2%和68.8%,S0全程积累并趋于稳定,经过60 d的驯化,SRB颗粒污泥平均粒径达到3 mm,硫酸盐还原反应启动成功。之后以驯化成熟的SRB颗粒污泥为载体,保持COD为50 mg/L,通过提高进水中NH+4-N和SO2-4负荷的方式启动硫酸盐型厌氧氨氧化。结果表明,NH_4~+-N和SO_4~(2-)去除效果逐步上升并稳定在50%以上,最高分别达到52.5%与53.7%。硫酸盐型厌氧氨氧化成功启动。 相似文献
717.
鉴于反硝化菌与厌氧氨氧化菌具有相似的生理特性,采用CSTR反应器研究了以异养反硝化污泥启动厌氧氨氧化系统的可行性,并考察了其对高氨氮废水的处理潜能。反应器运行170 d后,试验结果表明,此方法可快速培育出具有厌氧氨氧化活性的污泥,NH_4~+-N和NO_2~--N的去除率分别可达99.20%和99.69%。在此基础上考察了有机物浓度对厌氧氨氧化性能的影响,结果表明:低浓度(ρ(COD)≤150 mg/L)有机物可促进厌氧氨氧化活性,而高浓度(ρ(COD)≥200 mg/L)有机物抑制厌氧氨氧化进程,该系统最适ρ(COD)/ρ(NH_4~+-N)为2.14,此时NH_4~+-N和NO_2~--N的去除率分别为99.41%和99.65%。 相似文献
718.
Sarah M. Buckley Ruth H. Thurstan Andrew Tobin John M. Pandolfi 《Conservation biology》2017,31(6):1322-1332
Aggregations of individual animals that form for breeding purposes are a critical ecological process for many species, yet these aggregations are inherently vulnerable to exploitation. Studies of the decline of exploited populations that form breeding aggregations tend to focus on catch rate and thus often overlook reductions in geographic range. We tested the hypothesis that catch rate and site occupancy of exploited fish‐spawning aggregations (FSAs) decline in synchrony over time. We used the Spanish mackerel (Scomberomorus commerson) spawning‐aggregation fishery in the Great Barrier Reef as a case study. Data were compiled from historical newspaper archives, fisher knowledge, and contemporary fishery logbooks to reconstruct catch rates and exploitation trends from the inception of the fishery. Our fine‐scale analysis of catch and effort data spanned 103 years (1911–2013) and revealed a spatial expansion of fishing effort. Effort shifted offshore at a rate of 9.4 nm/decade, and 2.9 newly targeted FSAs were reported/decade. Spatial expansion of effort masked the sequential exploitation, commercial extinction, and loss of 70% of exploited FSAs. After standardizing for improvements in technological innovations, average catch rates declined by 90.5% from 1934 to 2011 (from 119.4 to 11.41 fish/vessel/trip). Mean catch rate of Spanish mackerel and occupancy of exploited mackerel FSAs were not significantly related. Our study revealed a special kind of shifting spatial baseline in which a contraction in exploited FSAs occurred undetected. Knowledge of temporally and spatially explicit information on FSAs can be relevant for the conservation and management of FSA species. 相似文献
719.
A spatially explicit estimate of the prewhaling abundance of the endangered North Atlantic right whale
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Sophie Monsarrat M. Grazia Pennino Tim D. Smith Randall R. Reeves Christine N. Meynard David M. Kaplan Ana S.L. Rodrigues 《Conservation biology》2016,30(4):783-791
The North Atlantic right whale (NARW) (Eubalaena glacialis) is one of the world's most threatened whales. It came close to extinction after nearly a millennium of exploitation and currently persists as a population of only approximately 500 individuals. Setting appropriate conservation targets for this species requires an understanding of its historical population size, as a baseline for measuring levels of depletion and progress toward recovery. This is made difficult by the scarcity of records over this species’ long whaling history. We sought to estimate the preexploitation population size of the North Atlantic right whale and understand how this species was distributed across its range. We used a spatially explicit data set on historical catches of North Pacific right whales (NPRWs) (Eubalaena japonica) to model the relationship between right whale relative density and the environment during the summer feeding season. Assuming the 2 right whale species select similar environments, we projected this model to the North Atlantic to predict how the relative abundance of NARWs varied across their range. We calibrated these relative abundances with estimates of the NPRW total prewhaling population size to obtain high and low estimates for the overall NARW population size prior to exploitation. The model predicted 9,075–21,328 right whales in the North Atlantic. The current NARW population is thus <6% of the historical North Atlantic carrying capacity and has enormous potential for recovery. According to the model, in June–September NARWs concentrated in 2 main feeding areas: east of the Grand Banks of Newfoundland and in the Norwegian Sea. These 2 areas may become important in the future as feeding grounds and may already be used more regularly by this endangered species than is thought. 相似文献
720.
J. A. Camiñas N. Cano D. Cortés V. Díaz del Río A. García J. P. Rubín 《Journal of Coastal Conservation》1998,4(1):43-50
In October 1992, the Oceanographic Centre of Málaga of the Spanish Oceanographical Institute (IEO) started a monitoring project,Ecomálaga, which collects physical, chemical, biological and sedimentological data from the Alborán Sea shelf. The project is coordinated
with similar projects in the Atlantic and Mediterranean Centres of IEO. The ultimate objective is to, understand the long-term
changes of the essential marine-environmental parameters.
So far, nine quarterly surveys have been carried out—from October 1992 to December 1994. The following variables were registered:abiotic: location weather, water temperature, salinity, pH, dissolved oxygen, chlorophyll a, nitrate, nitrite, phosphate, silicate,biotic: zooplankton biomass and species composition, and ichthyoplankton. The granulometric composition and organic matter content
of sediments are also included.
Data are stored in a computerized data base named Ecomálaga Data Base, with contributions from geology, physics, plankton
biology and marine chemistry. The data base not only contains separate files for each research topic, but also allows for
interchange between these files, resulting in a synoptic data output. It offers the users an output in the form of synthetic
records of each station sampled.
The analysis of the data indicates seasonal influences and ainshore-offshore gradient, as well as an Atlantic influence on
the stations located in the transect closest to the Strait of Gibraltar. 相似文献