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91.
降水中硫酸根离子监测的质量控制   总被引:1,自引:0,他引:1  
阐述了降水监测中硫酸根离子(SO^2-4)浓度测定过程中降水采样布点、样品分析的质量保证措施,以及确保降水监测分析全过程质量控制措施等的实践经验。  相似文献   
92.
辽宁省降水化学组份分析   总被引:2,自引:0,他引:2  
对辽宁省1991~1995年期间五城市降水中的化学组份进行了八种离子分析,研究了其时空分布,组成特征及变化规律.得出辽宁省存在降水污染的结论  相似文献   
93.
电除尘振打结构形式对除尘器除尘效率有较大的影响 ,通过对机械旋围挠臂振打和电磁振打的运行分析 ,认为顶部电磁锤振打有较好的清灰效果和合理的结构及布置  相似文献   
94.
中浅层天然气钻井废水处理技术试验研究   总被引:10,自引:0,他引:10  
针对中浅层天然气井的钻井废水处理进行了试验研究。根据现场处理条件,原水水质状况和试验结果,提出了可随原水水质和出水要求而进行组合的处理技术方案,并探讨了各处理过程的主要影响因素,给出了过程的主要工艺控制参数。  相似文献   
95.
1987-1989年春秋季在西南重庆、贵阳、成都和广元等地区采集大气颗粒物和雨水样品,测定了其中S和SO4^2-。探讨了颗粒物中S在粗细粒中的分布及水溶性S的百分比,估算了大气中S在气相(SO2)、液相(H2SO4)及固相(SO4^2-)中的分配比例,得知颗粒物中S对降雨的贡献率为18~50%。  相似文献   
96.
离子色谱法测定酸沉降样品中的阳离子   总被引:1,自引:0,他引:1  
用新型的阳离子分离柱和抑制柱分析雨水中的阳离子(Na^+、NH4^+、K^+、Mg^2+、Ca^2+)对这种方法的准确性和可行性进行了论证。  相似文献   
97.
A lack of information in databases for contamination risk assessment about the transport behaviour of the trivalent f-orbital elements in groundwater systems where calcite is at equilibrium motivated this study of Eu3+ uptake. The free drift technique was used to examine the effects of Eu3+ concentration, presence of Na+ or K+ and temperature, as well as calcite nucleation and precipitation kinetics, on the partitioning of calcite. Changes in surface composition and morphology resulting from exposure of single crystals of Iceland spar to Eu3+-bearing solutions were observed with X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). First results confirm that calcite has high affinity for Eu3+. Rates of nucleation and precipitation strongly affect the extent of uptake but the presence of Na+ and K+ has no effect, suggesting formation of solid solution as CaCO3–EuOHCO3. Surface-sensitive techniques prove that Eu3+ is adsorbed to calcite even when the surface is dissolving and adsorption is not accompanied by precipitation of a separate Eu3+-solid phase. Adsorbed Eu modifies calcite's dissolution behaviour, roughening terraces and rounding step edges, and producing surface morphology where some surface sites appear blocked. Results imply that Eu3+ concentrations in natural calcites are limited by Eu3+ availability rather than by a lack of ability to fit into calcite's atomic structure. This behaviour can probably be expected for other trivalent rare Earth elements (REE), actinides and fission products whose behaviour is similar to that of Eu3+. These elements are likely to be incorporated within the calcite bulk in systems where it is precipitating and the demonstrated strong partitioning ensures some uptake even where calcite is at or under saturation.  相似文献   
98.
简要介绍了斜气流技术机理,进行了均匀气流和斜气流状态下的粉尘沉降试验.通过试验数据分析,总结出了电除尘器内部两种气流分布状态下的粉尘沉降规律,指出斜气流技术的应用在提高除尘效率方面具有重大意义,并为斜气流技术的应用提出了一些建议.  相似文献   
99.
To increase reliability and electrical performance, shallow-trench isolation (STI) (or called field-oxide (FOX)) structures were inserted in the bulk-contact region of 60-V high-voltage p-channel lateral-diffused MOSFET (pLDMOS) devices in this study. As the FOX ratio increased with the addition of FOX segments, the value of the secondary breakdown current (It2) was enhanced. Therefore, the anti-electrostatic discharge ability of a pLDMOS device can be efficiently improved using this novel method. In addition, when the weighting ratio of FOX structures increased, variation values in the trigger voltage (Vt1) and holding voltage (Vh) of the corresponding samples remained within the range of approximately 1–4 V. The Ron value decreased because of more uniform conduction. The experimental data for the FOX structures added to the bulk revealed that the It2 value was improved by approximately 13.98%, Vh values were greater than 60 V (which is favorable for latch-up immunity), and the Ron value was decreased by approximately 12.62% compared with a reference device under test (without FOX segments in the bulk-contact region).  相似文献   
100.
Abstract

Laurentide humic acid has been titrated with paraquat and with selected divalent metal ions. In some cases, the humic acid was spiked with one cation before titration with another one. Several equivalence points were determined for the binding of the divalent cations, including paraquat. Three equivalence points agreed well with values predicted from the acidic properties of the humic acid. Eight independent experiments gave nine replicate values for an equivalence point that corresponds to 79.2 mole % of the total pairs of carboxyl groups. It is postulated that this represents a large molecular weight or structural fraction of the humic acid. The remaining 20.8 mole % can either bind one divalent cation to two carboxylate anions or bind one divalent cation to one carboxylate anion, with another anion providing for charge balance. Aggregation ‐ disaggregation and dissolution ‐precipitation phenomena may determine which case prevails, and they in turn are sensitive to the chemical compositions of samples. It should be possible to develop analytical chemical methods for characterizing the stoichiometric properties of humic acid samples.  相似文献   
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