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排序方式: 共有133条查询结果,搜索用时 46 毫秒
31.
32.
科卢韦齐(Kolwezi)铜矿床位于刚果(金)南部Kolwezi市区边部西南方向。通过研究铜矿体所在地层矿化元素的含量及变化系数,得出地层与矿体矿化特征的一致性。查明了矿床规模、矿体形态产状及矿物共生组合特征、物质成分特征、结构构造特征,并对矿物生成世代进行了详细划分,加深了对矿床成矿地质特征的认识。在前人研究的基础上,提出科卢韦齐铜矿床属于热液变质改造沉积型砂页岩铜(钴)矿床,具有典型的层控特征。 相似文献
33.
根据不同畜禽养殖污水产生系数与污染物平均浓度,计算出不同畜禽养殖粪污中COD、TN和TP的含量。并对畜禽养殖业产生的污染物对环境可能产生的污染影响进行分析。进一步说明畜禽粪污必须要妥善处理,否则会对环境造成危害,尤其是对水环境的影响将是巨大的。 相似文献
34.
Irizuki T Takimoto A Sako M Nomura R Kakuno K Wanishi A Kawano S 《Marine pollution bulletin》2011,62(10):2030-2041
This study focuses on the relationships of water and sediment quality with meiobenthos (Ostracoda) over the past 100 years, using a sediment core obtained from Suo-Nada in the Seto Inland Sea, Japan. We compared high-resolution ostracode results with geochemical and sedimentological data obtained from the study core as well as with rich environmental monitoring data that are available. R-mode cluster analysis revealed two bioassociations (BC, KA). Until the1960s, assemblages continued to show high diversity. They changed in approximately 1970, when excessive nutrients and organic matter began to be supplied, and most species decreased in number. All species of bioassociation BC were dominant again by the mid-1990s; however, those of bioassociation KA containing infaunal species did not increase and have been absent or rare since the 1970s because organic pollution of sediments has continued to date. This study provided robust baseline for ostracode-based long-term environmental monitoring in East Asia. 相似文献
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36.
介绍了一种重铬酸钾法测定高氯水体中COD的改进分析方法——氯耗氧曲线校正法,测定中不加隐蔽剂HgSO4,通过调整催化剂Ag2SO4的加入时间,测得表观COD值,再扣除Cl-对COD的贡献值,得出实际COD值。与标准方法相比,该法准确度高、精密度好,还可避免汞盐污染环境。 相似文献
37.
Kaan Yetilmezsoy Zehra Sapci-Zengin 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(1):13-26
A three-layer Artificial Neural Network (ANN) model (9:12:1) for the prediction of Chemical Oxygen Demand Removal Efficiency
(CODRE) of Upflow Anaerobic Sludge Blanket (UASB) reactors treating real cotton textile wastewater diluted with domestic wastewater
was presented. To validate the proposed method, an experimental study was carried out in three lab-scale UASB reactors to
investigate the treatment efficiency on total COD reduction. The reactors were operated for 80 days at mesophilic conditions
(36–37.5°C) in a temperature-controlled water bath with two hydraulic retention times (HRT) of 4.5 and 9.0 days and with organic
loading rates (OLR) between 0.072 and 0.602 kg COD/m3/day. Five different dilution ratios of 15, 30, 40, 45 and 60% with domestic wastewater were employed to represent seasonal
fluctuations, respectively. The study was undertaken in a pH range of 6.20–8.06 and an alkalinity range of 1,350–1,855 mg/l
CaCO3. The concentrations of volatile fatty acids (VFA) and total suspended solids (TSS) were observed between 420 and 720 mg/l
CH3COOH and 68–338 mg/l, respectively. In the study, a wide range of influent COD concentrations (CODi) between 651 and 4,044 mg/l in feeding was carried out. CODRE of UASB reactors being output parameter of the conducted anaerobic
treatment was estimated by nine input parameters such as HRT, pH, CODi concentration, operating temperature, alkalinity, VFA concentration, dilution ratio (DR), OLR, and TSS concentration. After
backpropagation (BP) training combined with principal component analysis (PCA), the ANN model predicted CODRE values based
on experimental data and all the predictions were proven to be satisfactory with a correlation coefficient of about 0.8245.
In the ANN study, the Levenberg-Marquardt Algorithm (LMA) was found as the best of 11 BP algorithms. In addition to determination
of the optimal ANN structure, a linear-nonlinear study was also employed to investigate the effects of input variables on
CODRE values in this study. Both ANN outputs and linear-nonlinear study results were compared and advantages and further developments
were evaluated. 相似文献
38.
结合上海老港垃圾填埋场渗滤液的实际监测数据.建立了COD降解模型.介绍了利用Excel及其非线性规划求解工具拟合并优化填埋场渗滤液COD降解曲线的新方法。结果表明:①填埋场渗滤液COD衰减过程符合一级反应过程;②用Excel软件包拟合曲线简捷明了.拟和精度高,具有较大的工程应用价值。 相似文献
39.
In this work, the treatment of actual agro‐industrial wastewaters (IWW) by a UV/H2O2 process has been investigated. The aqueous wastes were received from industrial olive oil mills and then treated by laboratory scale physicochemical methods, i. e., coagulation using ferrous and aluminum sulfate, decantation, filtration and adsorption on activated carbon. These wastes are brown colored effluents and have a residual chemical oxygen demand (COD) in the range of 1800 to 3500 mgO2 L–1, which cannot be further eliminated with physicochemical processes. The UV/H2O2 treatments were carried out under monochromatic irradiation at 254 nm using a thermostated reactor equipped with a mercury vapor lamp located in an axial position. The effects of initial H2O2 concentration, initial COD, pH and temperature have been studied in order to determine the optimum conditions for maximum color and COD removals. The experimental results reveal the suitability of the UV/H2O2 process for both removal of high levels of COD and effectively decolorizing the solution. In particular, 95% of color removal and 90% of COD removal were obtained under conditions of pH = 5 and 32°C using 2.75 g H2O2 g–1 COD L–1 during 6 h of UV‐irradiation. The treatment is unaffected by pH over the range 2 to 9. In addition, the COD removal is improved by increasing the temperature, whereas the color removal has not been affected by this parameter. The results show that the hydroxyl radicals generated from the catalytic decomposition of H2O2 by UV‐irradiation of the solution could be successfully used to mineralize the organics contained in IWW. The mineralization of the organics seems to occur in three main sequential steps: the first is the rapid decomposition of tannins leading to aromatic compounds, which are confirmed by the decolorization of the IWW; the second step corresponds to the oxidation of aromatics leading to aliphatic intermediates, which occurs by the cleavage of an aromatic ring, and is established by the removal of aromatics, and the final step is the slow oxidation of the aliphatic intermediates, which is measured by the COD removal. 相似文献
40.
Alper Erdem Yılmaz Yeşim Dede Sağsöz Baybars Ali Fil Murat Tolga Yılmaz 《洁净——土壤、空气、水》2023,51(1):2200032
In this study, domestic wastewater was used as the electrolyte. The work was carried out with an up-flow tubular reactor, made of stainless steel that was used as cathode, while the anode electrode material was aluminum and varying values of flow regime (25, 50, 75 and 100 mL/s for continuous system), initial pH value (5, 6, 7 and 7.8) and current intensity (10, 15 and 20 A) were applied. For domestic wastewater with natural pH, the effluent pH was >9 in the batch system, while in the continuous system the pH was 8–8.5. Likewise, while the effluent temperature was up to 60°C in the batch system, it was at most 35°C in the continuous system. However, the energy consumption values in the continuous system were considerably lower compared with the batch system. At a current intensity of 10 A, 80 kWh of energy per unit volume was consumed in the batch system, while it was 50 kWh for the continuous system. The present results show that the batch system can be used for small wastewater streams whereas the continuous system can be used for large wastewater streams for domestic wastewater treatment. 相似文献