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201.
四川盆地下中三叠统盐卤分布广泛,是四川探盐找钾的重要时代。通过区域地质背景条件分析,其盐类保存、水动力条件和水化学特征在不同水文地质区表现不一,反映在储层的水型也极不一致,按水中阴、阳离子优势组分异常水点分为SO4-Ca、SO4-Na和Cl-Na3种类型。利用异常水点离子的比例系数在海水浓缩曲线图上的落点位置,判别水点成因类型,从而发现盆地东北部宣汉、盆地西部平落和盆地东部万县向斜周边背斜水点具含钾溶滤水特征,值得重视和进一步开展找钾探索。 相似文献
202.
A simple approach is proposed for identifying areas vulnerable to groundwater overdraft. The methodology utilizes GIS techniques
to analyze and evaluate controlling factors in areas with little data. The proposed methodology was applied in Arusha. Water
demand in Arusha Municipality and its environs has increased to about 5.3% annually since 1999. Groundwater levels have declined.
The aquifer hydrogeological variables were evaluated for impact to potential groundwater overdraft by overlay and index techniques.
The spatial distribution of overdraft vulnerability was discussed. The northwestern part of Arusha is the most vulnerable
to overdraft and possible serious environmental impacts. The Loruvani area has the most potential for aquifer development
due to its permeability, high recharge rate, massive aquifer thickness and low drawdown. 相似文献
203.
ICP-AES测定海洋生物体中13种元素的微波消解条件优化 总被引:2,自引:1,他引:2
报道了微波密闭消解正交试验条件优化电感耦合等离子体发射光谱法(ICP-AES),同时测定8种海洋生物体中硒、铁、锰、锌、钙、镁、锶、砷、镉、铬、铜、铅和镍等13种元素含量的实验结果。优化后的样品消解条件为加入的HNO3V:H O2 2V=6.0 mL:1.0 mL,第二步程序升温温度为170℃,消解时间20 min;测定标准曲线相关系数大于0.999,相对标准偏差为0.30%~2.55%,加标回收率为92.0%~104.8%,方法检出限为0.0010~0.0468μg/g。结果表明,优化后方法测定操作简便、具有高的灵敏度、准确度和精密度,且能多元素同时测定,适合于海洋生物样品中这些元素含量的准确测定,并可为评估海产品食用安全提供科学依据。 相似文献
204.
《China Geology》2022,5(3):421-428
This paper aims to investigate the present situation and transfer mechanisms of microplastics in lacustrine sediments in the Qinghai-Tibet Plateau. The study surveyed the average abundance of microplastics in sediments. The abundance of microplastics in sediments of lakes from the Qinghai-Tibet Plateau is 17.22–2643.65 items/kg DW and 0–60.63 items/kg DW based on the data of the Qinghai Lake and the Siying Co Basin. The microplastic abundance in sediments from small and medium lakes is very high compared to that in other areas in the world. Like microplastics in other lakes of the world, those in the lakes in the Qinghai-Tibet Plateau mainly include organic polymers PA, PET, PE, and PP and are primarily in the shape of fibers and fragments. The microplastic pollution of lacustrine sediments in the Qinghai-Tibet Plateau is affected by natural changes and by human activities, and the concentration of microplastics in lacustrine ecosystems gradually increases through food chains. Furthermore, the paper suggests the relevant administrative departments of the Qinghai-Tibet Plateau strengthen waste management while developing tourism and pay much attention to the impacts of microplastics in water environments. This study provides a reference for preventing and controlling microplastic contamination in the Qinghai-Tibet Plateau.©2022 China Geology Editorial Office. 相似文献
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207.
《Limnologica》2017
This multi-year pilot study evaluated a proposed field method for its effectiveness in the collection of a benthic macroinvertebrate sample adequate for use in the condition assessment of streams and rivers in the Neuquén Province, Argentina. A total of 13 sites, distributed across three rivers, were sampled. At each site, benthic macroinvertebrates were collected at 11 transects. Each sample was processed independently in the field and laboratory. Based on a literature review and resource considerations, the collection of 300 organisms (minimum) at each site was determined to be necessary to support a robust condition assessment, and therefore, selected as the criterion for judging the adequacy of the method. This targeted number of organisms was collected at all sites, at a minimum, when collections from all 11 transects were combined. Subsequent bootstrapping analysis of data was used to estimate whether collecting at fewer transects would reach the minimum target number of organisms for all sites. In a subset of sites, the total number of organisms frequently fell below the target when fewer than 11 transects collections were combined.Site conditions where <300 organisms might be collected are discussed. These preliminary results suggest that the proposed field method results in a sample that is adequate for robust condition assessment of the rivers and streams of interest. When data become available from a broader range of sites, the adequacy of the field method should be reassessed. 相似文献
208.
《China Geology》2020,3(3):455-461
Many landslide disasters, which tend to result in significant damage, are caused by typhoon-triggered rainstorms. In this case, it is very important to study the dynamic characteristics of the hydrological response of landslide bodies since it enables the early warning and prediction of landslide disasters in typhoon periods. To investigate the dynamic mechanisms of groundwater in a landslide body under typhoon-triggered rainstorm conditions, the authors selected the landslide occurring in Zhonglin Village, Wencheng County, China (also referred to as Zhonglin Village landslide) as a case study. The transient seepage field characteristics of groundwater in the landslide body were simulated with two different rainfall models by using the finite element method (FEM). The research results show that the impact of typhoon-triggered rainstorms on landslides can be divided into three stages: (i) Rapid rise of groundwater level; (ii) infiltration of groundwater from the surface to deeper level, and (iii) surface runoff erosion. Moreover, the infiltration rate of groundwater in the landslide body is mainly affected by the intensity of typhoon-induced rainfall. It can be deduced that higher rainfall intensity leads to a greater potential difference and a higher infiltration rate. The rainfall intensity also determines the development mode of landslide deformation and destruction. 相似文献
209.
Slovakia has many areas rich in thermal waters one of which is the Hornonitrianska kotlina depression. At four localities
three types of waters are found. The first belongs to the Ca–Mg–HCO3 type with T.D.S. 0.7 g/l, the second to the Ca–Mg–SO4 type with T.D.S. 1.37–2.01 g/l and the third to the Ca–Mg–SO4–HCO3 type with T.D.S. 0.97 g/l. Discharge at individual localities varies up to 30 l/s and temperatures of water reach 32.5–66.6 °C.
The waters are predominantly used for healing, rehabilitation purposes, recreation and heating.
Received: 8 March 1999 · Accepted: 7 June 1999 相似文献
210.