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931.
H.T. Yan S.Y. Hu U. Blaha W. Rösler X.M. Duan E. Appel 《Journal of Applied Geophysics》2011,75(2):211-219
A preliminary magnetic study around Meishan steel mill in Nanjing (SE China) was carried out combining geochemical analysis with scanning electron microscopy (SEM) to prove that paddy soil can be a suitable target for environmental study on heavy metal pollution. Magnetic background investigation showed a strong variation in this area due to different land uses and soil types. Magnetic susceptibilities (MS) measured on forest soils are much higher than in paddy fields, and values below 20 cm of the soil surface in forest with parent material of Xiashu loess are several times higher than in paddy soil with parent material of fluvisol. Measurements on vertical profiles show that paddy soil has a very low and stable magnetic background with mass-specific MS around 15 × 10− 8 m3 kg− 1. A strong enhancement of MS values is found in the upper ~ 20 cm of paddy soil predominated by multidomain and pseudo single domain magnetite. However, relatively low S-ratios (0.57 to 0.85) reveal a significant contribution of imperfect anti-ferromagnetic minerals. Detailed research on a paddy soil core at site C719 near the steel mill indicates strong correlation between magnetic mineral concentration-related parameters (χ, ARM, SIRM) and heavy metal concentrations of Cu, Pb and Zn. In addition, typical anthropogenic Fe-spherules are detected in top paddy soil by means of SEM, which indicates that the increase of susceptibility in upper soil is mainly caused by steel mill emission. Mapping of MS in paddy fields across the steel mill area shows a decrease of MS with the distance to the major emission zone. Positive correlation between χ and Zn is found by measuring surface soil samples around the steel mill. Because of low background and high homogeneity of the ~ 20 cm uppermost mixing layer paddy fields are especially suitable for magnetic surface mapping of heavy metal pollution. 相似文献
932.
Qiu Qiu Yutao Wang Zhongyi Yang Junliang Xin Jiangang Yuan Jianbing Wang Guorong Xin 《洁净——土壤、空气、水》2011,39(11):925-932
To reduce the potential risks of cadmium (Cd) and lead (Pb) entering the human food chain in vegetables, two pot experiments (Exp. 1 and Exp. 2) were carried out to screen for Cd and Pb pollution‐safe cultivars (PSCs) of Chinese flowering cabbage (Brassica parachinensis L.). The three Cd treatments in Exp. 1 (0.114, 0.667, and 1.127 mg kg?1) showed that Chinese flowering cabbage could easily take up Cd from polluted soils, and there were wide variations in Cd accumulation among different cultivars. The Cd accumulation trait at cultivar level was rather stable under different soil Cd treatments. In Exp. 2, seven cultivars that had been shown in Exp. 1 to be typical high or low accumulators of Cd were selected and six Cd + Pb joint exposure treatments were applied to them. The results showed that there were similar trends of accumulation between Cd and Pb for the tested cultivars, but Pb accumulation by the species was much poorer than that of Cd. It was worth noting that an increase in soil Pb levels significantly (p < 0.01) depressed shoot Cd accumulation. Six cultivars were selected as Cd + Pb PSCs. This study showed that it is feasible to apply a PSC strategy in Chinese flowering cabbage cultivation, to cope with the Cd and Pb contamination commonly found in agricultural soils. 相似文献
933.
根据国家开展地理国情监测工作的要求,结合上海规划和土地管理中的实际情况,阐述了对地理市情监测主要内容和技术方法的认识和思考,分析了上海地区开展此项工作的基础以及存在的主要难点。 相似文献
934.
935.
云南省公路水毁时空分布与态势 总被引:1,自引:0,他引:1
云南省不同尺度地质环境脆弱,公路作为带状建筑展布于复杂、脆弱地质环境中,公路水毁时空分布规律是复杂的。运用统计分析和实地调查方法,分析云南省公路水毁时空分布和发展态势。突降暴雨易即时诱发公路水毁,公路水毁具有单点性;普降暴雨也易即时诱发公路水毁,公路水毁具有带状性,水毁链效应显著;降雨强度不高时,公路水毁发生略有滞后性。云南省公路水毁主要发生在6—8月,7月是高发期;在20世纪,公路水毁周期一般为2~3 a,21世纪公路水毁周期一般为4 a。滇西公路水毁密度大于滇东,滇北大于滇南,滇中公路水毁主要分布在滇中边缘地带;公路等级越低,公路水毁越严重;不同地区公路水毁种类有差别。云南省公路水毁目前仍处于发展的态势。 相似文献
936.
地勘单位适应市场经济新的管理制度势在必行,合同管理就是其中一项重要的管理工作.重视并加强经济合同管理,依法维护自身合法权益,是地勘单位一项刻不容缓的任务. 相似文献
937.
D. Drew 《Environmental Geology》1996,28(3):137-144
The Burren plateau of County Clare is a classic example of a plateau karst characterised by patchy, thin soils, a lack of
defined surface drainage, and in the instance of the Burren, a rich floristic, archaeological and landscape heritage.
Since accession to the European Union and, in particular, as a result of Common Agricultural Policy initiatives, attempts
have been made to raise farm incomes and to modernise agriculture in areas such as the Burren.
Due to the encouragement of land reclamation and silage production has largely replaced hay farming for winter fodder. These
changes pose a threat to groundwater quality by enhancing the leaching of artificial fertilizers or of organic pollutants.
The Burren is highly vulnerable to water pollution from silage effluent because of its thin or absent soils and its highly
karstified aquifers.
A full survey of silage clamps was made in the summers of 1991 and 1992. For each site data were collected to derive the following:
mass of silage, effluent produced, hazard rating of site to groundwater, likely discharge of effluent to groundwater and groundwater
dilution index. About 60% of clamps were considered to be high risk and 23% medium risk. About 92% of all sites probably allow
some effluent to infiltrate groundwater.
Received: 1 June 1995 · Accepted: 4 December 1995 相似文献
938.
939.
战略性矿产是国家资源宏观调控和的监督管理的重点对象, 加强战略性矿产研究、明确自身比较优势和薄弱环节。战略性非金属矿产是指对国家经济发展和国家安全至关重要的非金属矿产。建议将萤石、高纯石英、石墨、硼、金红石、硅藻土、叶蜡石、石榴子石、金刚石、泥炭、重晶石等11种非金属矿产为战略性非金属矿产, 对其重要性及用途、资源供需形势等进行研究, 为国家制定勘查投入规划及制定矿业发展政策提供参考。对于完善全国矿产资源规划中的战略性矿产资源目录、为国家相关产业政策制定提供借鉴参考具有重要意义。 相似文献
940.
The study aimed to assess the heavy metals(K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Pb, Sr, Zr) contamination in the soil of mine affected Singaran river basin and to analyse spatial variation in the contamination level considering 32 soil samples. Elemental analysis of soil samples has been performed through Energy Dispersive X-ray Analysis(EDX) to quantify the elemental concentration(mg kgà1). Heavy metal concentrations have been assessed through geo-accumulation index(Igeo) and enrichment factor(EF).Indices showed soils have moderate accumulation of most of the metals with moderate enrichment of Sr,Zr, Zn, Cu and Ni. Soil contamination level assessment has been carried out using indices like Contamination Factor(CF), degree of contamination(C_(deg)), modified degree of contamination(m C_(deg)) and Pollution Load Index(PLI). CF shows moderate to considerable contamination by Sr, Zr, Ca, Cu, Mn, Zn and Ni. Mean indices values(m C_(deg)and PLI for the entire basin are 3.38 and 2.23 respectively) show low to moderate level of soil contamination. These indices result have been mapped and analysed in GIS platform to get spatial variation of pollution level. Opencast mines dominate middle catchment area and so is comparatively contaminated. Sample sites 11, 18 and 25 evidenced high values of all indices of pollution load. From the ecological standpoint Ecological Risk Factor(Er) and Potential Ecological Risk Index(RI) have been estimated to assess regional threat to native soil environment and it shows low ecological risk potential. Analysis shows that mine dominated soil of the entire Singaran basin is less contaminated in all respect but tends to the moderate contamination level at the mid-catchment area,especially by Sr, Zr, Zn, Cu and Ni. 相似文献