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291.
292.
BRIAN J. GODFREY 《Geographical review》1997,87(3):309-333
ABSTRACT. San Francisco has arisen as an “instant city” not once but three times: after the California Gold Rush (1849–1875), following the 1906 earthquake and fire (1906–1930), and with the modern high-rise city (1960–1985). These pivotal periods of intense city building, each about twenty-five years in duration, have been separated by a generation of relative stability. Current redevelopment activity raises an intriguing historical-geographical question: Is a fourth instant city in the making? 相似文献
293.
Gary L. Raines Katherine A. Connors Lesley B. Chorlton 《Natural Resources Research》2007,16(2):191-198
Geologic maps are a fundamental data source used to define mineral-resource potential tracts for the first step of a mineral
resource assessment. Further, it is generally believed that the scale of the geologic map is a critical consideration. Previously
published research has demonstrated that the U.S. Geological Survey porphyry tracts identified for the United States, which
are based on 1:500,000-scale geology and larger scale data and published at 1:1,000,000 scale, can be approximated using a
more generalized 1:2,500,000-scale geologic map. Comparison of the USGS porphyry tracts for the United States with weights-of-evidence
models made using a 1:10,000,000-scale geologic map, which was made for petroleum applications, and a 1:35,000,000-scale geologic
map, which was created as context for the distribution of porphyry deposits, demonstrates that, again, the USGS US porphyry
tracts identified are similar to tracts defined on features from these small scale maps. In fact, the results using the 1:35,000,000-scale
map show a slightly higher correlation with the USGS US tract definition, probably because the conceptual context for this
small-scale map is more appropriate for porphyry tract definition than either of the other maps. This finding demonstrates
that geologic maps are conceptual maps. The map information shown in each map is selected and generalized for the map to display
the concepts deemed important for the map maker’s purpose. Some geologic maps of small scale prove to be useful for regional
mineral-resource tract definition, despite the decrease in spatial accuracy with decreasing scale. The utility of a particular
geologic map for a particular application is critically dependent on the alignment of the intention of the map maker with
the application. 相似文献
294.
295.
韩再生 《水文地质工程地质》2004,31(3):115-116
世界地下水资源图由联合国教科文组织、世界地质图委员会、国际水文地质学家协会、国际原子能机构和德国地球科学及自然资源研究院共同组织编制,其目标是利用地理信息系统在全球尺度上汇总地下水资源,以比例尺1:25M的图件为基础,为国际社会了解世界地下水系统提供基础。2004年3月在法国巴黎召开了世界地下水资源图指导委员会工作会议,8月将在第32届国际地质大会上展示1:50M世界地下水资源图。最终的成果将于2006年国际水文地质学家协会成立50周年之际出版。 相似文献
296.
国外国土规划的特点和新动向 总被引:9,自引:2,他引:9
本文首先阐明国外国土规划的基本概念和体系结构,然后对欧盟、日本、韩国及东南亚等国家的新世纪国土规划体系和制度改革的特点、新理念、发展趋势进行比较研究。最后,指出国外国土规划对中国国土规划的启示和中国新时期国土规划编制的重要性。 相似文献
297.
2003年全球重大天气与气候事件 总被引:3,自引:0,他引:3
全球气候持续偏暖。南亚、欧洲大部和北美洲冬季出现异常严寒 ,许多地区遇到数十年未见的暴风雪 (雨 )天气。夏季欧亚大陆和北美的多个国家出现持续高温酷热天气 ,严重干旱导致森林火灾频发 ,经济损失惨重。南亚、东南亚夏季暴雨频繁 ,造成严重洪涝灾害。非洲干旱持续 ,局部发生洪涝。美国 5月遭受特大龙卷风袭击 ,北大西洋飓风较常年显著偏多。 相似文献
298.
世界钴矿资源及其研究进展述评 总被引:3,自引:0,他引:3
本文概述了当前世界钴资源状况,钴矿床分类及国内外钴矿床勘查与研究的最新进展,全球钴资源丰富,但分布较为集中,沉积型砂岩容矿的铜钴矿床和含钴的岩浆岩型硫化铜镍矿床是两个最重要的钴矿床类型。尽管钴多数以铜-镍、铜、铁等矿床的伴生金属产出,国外的研究也主要集中在层控铜钴矿床之上,中国近几年却在华北地台北缘东段、西部 中央造山带、赣西地区等陆续发现了一些不同元素组合,不同成因类型且为独立的或以钴为主的钴矿床,钴矿床勘查的重大突破既对开拓钴矿床成矿学研究具有重要理论意义,也为弥补国内钴资源长期供应不足具有重要现实意义。 相似文献
299.
Dyman T. S. Crovelli R. A. Bartberger C. E. Takahashi K. I. 《Natural Resources Research》2002,11(3):207-218
The U.S. Geological Survey recently assessed undiscovered conventional gas and oil resources in eight regions of the world outside the U.S. The resources assessed were those estimated to have the potential to be added to reserves within the next thirty years. This study is a worldwide analysis of the estimated volumes and distribution of deep (>4.5 km or about 15,000 ft), undiscovered conventional natural gas resources based on this assessment. Two hundred forty-six assessment units in 128 priority geologic provinces, 96 countries, and two jointly held areas were assessed using a probabilistic Total Petroleum System approach. Priority geologic provinces were selected from a ranking of 937 provinces worldwide. The U.S. Geological Survey World Petroleum Assessment Team did not assess undiscovered petroleum resources in the U.S. For this report, mean estimated volumes of deep conventional undiscovered gas resources in the U.S. are taken from estimates of 101 deep plays (out of a total of 550 conventional plays in the U.S.) from the U.S. Geological Survey's 1995 National Assessment of Oil and Gas Resources. A probabilistic method was designed to subdivide gas resources into depth slices using a median-based triangular probability distribution as a model for drilling depth to estimate the percentages of estimated gas resources below various depths. For both the World Petroleum Assessment 2000 and the 1995 National Assessment of Oil and Gas Resources, minimum, median, and maximum depths were assigned to each assessment unit and play; these depths were used in our analysis. Two-hundred seventy-four deep assessment units and plays in 124 petroleum provinces were identified for the U.S. and the world. These assessment units and plays contain a mean undiscovered conventional gas resource of 844 trillion cubic ft (Tcf) occuring at depths below 4.5 km. The deep undiscovered conventional gas resource (844 Tcf) is about 17% of the total world gas resource (4,928 Tcf) based on the provinces assessed and includes a mean estimate of 259 Tcf of U.S. gas from the U.S. 1995 National Assessment. Of the eight regions, the Former Soviet Union (Region 1) contains the largest estimated volume of undiscovered deep gas with a mean resource of343 Tcf. 相似文献
300.
秦岭终南山地质遗迹全球对比及世界地质公园建立 总被引:2,自引:0,他引:2
秦岭中段终南山地区地质现象复杂,地质遗迹资源数量多、种类全,分布有典型地层剖面、岩浆活动遗迹、构造剖面及典型构造运动遗迹、地质地貌景观等多种类型地质遗迹。这些遗迹在环境、造山带和大陆动力学等研究方面有重要的科学意义,许多还具有景观价值。全球对比表明,区内多种地质遗迹具有独特性和垄断性。为保护好地质遗迹开展科研和旅游并兼顾生态保护,建立终南山世界地质公园是最佳选择。为此,划分出三级地质遗迹保护区及生态保护区,在保护区内设立若干特殊遗迹保护点,并提出相应管理措施。同时,作为大型地质公园,在分区开发保护的基础上,利用中应充分注意各种资源及各园区的有效整合问题。 相似文献