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排序方式: 共有131条查询结果,搜索用时 15 毫秒
61.
羟基磷灰石吸附水溶液中Cd^2+的影响因素的研究   总被引:14,自引:2,他引:14  
对羟基磷灰石(Hap)固定水溶性Cd2+的影响因素进行了较为系统的实验研究.实验表明去除率与Cd2+初始浓度呈负相关,在Cd2+初始浓度<10 mg/L时,与作用时间、pH值、Hap用量呈正相关,温度对去除率的影响较小.通过正交实验确定了最佳吸附条件Hap用量为5 g/L,pH值为6,作用时间5 min.  相似文献   
62.
张胜  张翠云  叶思源 《地球学报》2003,24(2):187-192
文章通过河北平原山前地区包气带土体的氮素循环及硝酸盐污染地下水的过程,对包气带土体与微生物细菌对三氮的运移转化作用进行了实验研究,介绍了用于溶质运移的预测与准确估算进入地下水的氮素含量求其参数的实验方法及特点。  相似文献   
63.
蛋白质和核糖核酸在阿哈湖沉积物中的变化特征   总被引:3,自引:0,他引:3  
阿哈湖沉积物中的蛋白质和核糖核酸(RNA)随时间和沉积深度的增加逐渐被分解,其含量分别在沉积深度为17cm和19cm以后明显降低,而它们的分解产物氨基酸和核苷酸却有不同的变化规律,氨基酸在沉积深度为27-30cm的孔隙水中含量较高,这种变化规律与微生物对氨基酸和核苷酸利用的差异有关,由于地质聚合作用及矿物和有机聚合物对蛋白质的吸附作用的影响,蛋白质在沉积深度为17cm以后仍保留了一定的含量。  相似文献   
64.
磷块岩对二价镉离子的吸附性能研究   总被引:12,自引:0,他引:12  
刘羽  胥焕岩 《矿物学报》2001,21(3):406-412
用宜昌、海口、保康等地磷块岩对水溶液中镉离子的吸附实验结果表明,影响吸附效果的主要因素有介质的酸度,作用时间,初始Cd^2 浓度和样品用量。在pH=6,作用时间为15min,初始Cd^2 浓度为30mg/L的实验条件下,宜昌硅质磷块岩对镉离子的去除率可达98%,去除容量为4.5mg/g(样品),吸附效果最好,海口的效果次之,而保康钙质磷块岩的效果最差。上述差异可能与这些磷块岩的矿物成分和结晶化学特性之间的差异有关。  相似文献   
65.
根据物质呈纳米级状态时,其物理性质发生显著的变化,认为由其作为分散相分散于不同的分散介质(气体、液体和固体)中所构成的气溶胶、胶体溶液或固体溶胶,尤其是胶体溶液对运移成矿物质尤为重要,而对于被运移的胶粒来说,自身凝聚或被其他载体矿物或岩石的吸附富集将是一种重要的成矿作用,这特别有助于解释微细浸染型金矿、砂金矿及某些稀有及分散元素矿床的成因。  相似文献   
66.
通过对细粒天然磁铁矿的穆斯堡尔谱研究和对华北冀东油田第三系砂岩样品的磁性载体成分、成因、剩磁稳定性和特征剩磁方向的研究,探讨了烃类的化学吸附作用与岩石剩磁稳定性之间的关系,烃类的化学吸附作用能够降低岩石的剩磁稳定性,因此,可能会导致产生次生剩磁。这一认识为客观全面地了解各种次生剩磁的成因、研究重磁化现象的时空分布规律,进而为探索新的磁清洗方法和应用岩石磁学方法研究含油气地层的地质问题提供了新的思路  相似文献   
67.
Phosphate is one of the important nutrients for plant growth. In acidic and highly weathered soils, phosphate is ready to adsorb on Al and Fe oxides and transform into sparsely soluble Fe-P and Al-P solid phases, greatly reducing phosphate bioavailability. Aluminum and iron oxides in soils are important sinks for both phosphate and fluoride. In acidic soils, fluoride adsorption can dramatically facilitate dissolution of Al- and Fe-containing phases, which may influence the distribution and migration of both pollutants and nutrients including phosphate. To date, little information is available on mutual effects of fluoride and phosphate in fluoride-contaminated acidic soils. The objective of this study is to evaluate mutual effects of fluoride and phosphate on their adsorption/desorption in red soil, collected fi'om Yingtan, Jiangxi Province, China, using a batch equilibrium method. The following results and conclusions were obtained. In heavily fluoride-contaminated soils, the adsorption of both fluoride and phosphate decreases with an increase in solution pH. Phosphate adsorption decreases progressively with increasing concentration of fluoride, suggesting that fluoride competes with phosphate for adsorption sites.  相似文献   
68.
Livestock wastes applied to agricultural land are potential sources of steroidal hormones (estradiol (E2), estrone (E1), and estriol (E3)) that can adversely affect the aquatic ecosystem as endocrine disruptors. But the effects of plants on the fate of estrogen in the environment are not clearly known. In the present report, the behavior of E1, E2 and E3 added to the rhizospheric soil in various concentrations and its effect on plant growth were examined by estrogen batch sorption test, plant pot test and estrogen extraction test. Trifolium repens was grown on the soil spiked with E2 or a mixture of E1, E2 and E3. Pots without plant were prepared as controls. All pots were watered in 50 ml dose almost every day, and the rhizosheric soil and plant body were collected 7, 19, 26, 33 days after planting. The soil was sequentially extracted with Milli-Q water, and methanol / 1M acetic acid solvent followed by methanol wash at the solid to liquid ratio of 1 : 4 (g/mL). Extracts were analyzed for El, E2 and E3 using a Shimadzu GCMS-QP5050. Plant dry weight (4 hours, 105 ℃) was measured as an indicator of plant growth. In batch sorption tests, E1 and E2 concentrations in the liquid phase significantly decreased within 24 hours after the addition of estrogen. The sum of methanol / 1M acetic acid extractable E 1 and E2 in the soil decreased to half of the initial added amount within 7 days. Reduction in total estrogenic activity of the soil extracts (estimated as 0.01CE1+CE2+0.1CE3 where CE1, CE2 and CE3 are respective El, E2 and E3 concentrations per unit soil weight) continued for 1 month due to slow oxidation of E2 to E1. Desorption of E2 from soil during the pot experiment was higher than expected from the sorption experiment.  相似文献   
69.
Heavy metals in soils may adversely affect environmental quality. This paper studied the influence of copper concentration, pH, temperature, and the ratio of solid to solution on the desorption of Zn in kaolin from Suzhou, China in a background solution of 0.01M CaC12 by batch extraction experiments. At 0, 5, 50, 100 mg/L Cu concentrations, for each 0.5, increase in pH between about 1.80 and 3.04 percent desorption decreasing by 3.80%, 13.87%, 9.97%, and 7.65%, respectively. The pH 50 ( pH at 50% Zn desorption) was found to follow the sequence of Cu (5mg/L, pH 50=2.60).  相似文献   
70.
Sediment from three different trophic states (Meiliang Bay, Xukou Bay and Gonghu Bay) in spring, summer, autumn and winter were collected and analyzed in Taihu Lake. At the same time, seasonal variations in adsorption/desorption equilibrium were investigated with corresponding sediments from these three trophic states, including adsorption efficiency, adsorption/desorption equilibrium concentration and equilibrium adsorption quantity. Variations of TP and P fractions' concentrations in the initial and end of adsorption experiment were also documented in order to find the most active P fractions. The following conclusions were obtained: (1) Concentrations of total phosphorus (TP) and its fractions in the sediments were coincided with the trophic state of corresponding overlying water, Meiliang Bay〉Gonghu Bay〉Xukou Bay. The Meiliang Bay located in the north of Taihu Lake is in the eutrophic state and belong to alga-type lake; the Xukou Bay located in the northeast of Taihu Lake is relatively clean lake region; the Gonghu Bay is located in the east of Taihu Lake is in the meso-trophic state. Fe-P concentrations in the Meiliang Bay, Gonghu By and Xukou Bay account for 35.1%-70.9%, 19.6%-26.8%, 16.5%-34.3% of TP, Ca-P account for 20.6%-43.7%, 40.7%-45.0%, 23.0%-41.1% and OP accounts for 15.3%-20.2%, 28.4%-37.4%, 23.6%-54.3%, which changes obviously in different seasons. Fe-P is the major fraction in the eutrophic lake region, which is significantly correlated with the TP concentrations. (2) Adsorption and desorption processes in these three lake regions varied with season.  相似文献   
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