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991.
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回顾了武汉大学遥感信息工程学院近几年来在遥感科学与技术新专业设置、科研建设成果、教学改革、教材建设和人才培养等方面的情况,介绍了摄影测量与遥感重点学科今后三年的建设目标和发展方向。 相似文献
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Three geo-archaeological sites at the North Coast and Alexandria, namely, the Alexandria wall (El Shalalat Park site), Abu Soir temple, and Marina excavations, were investigated to determine the negative impact of a salty environmental condition. The monuments suffer from rock decay of different rates. The geo-archaeological sites were built mainly from oolitic limestone blocks (i.e., the Alexandria wall at the El Shalalat Park site and Abu Soir temple) or excavated on them (i.e., Marina excavations). Field inspection and a lab analysis were carried out to understand the weathering mechanism. Salt weathering criteria such as disintegration, pitting, scaling, exfoliation, and honeycomb are observed on the Alexandria wall and upper parts of the Abu Soir temple, while dangerous cracks are detected on the Marina excavation tombs. The petrographic study of the oolitic limestone samples shows that they consist mainly of oolities and drusy sparite as a cement (oolitic grainstone). Some oolities have quartz grains as nuclei. Hydrochemical analysis shows that the total dissolved salts of extracted solutions of the North Coast quarry samples range from 539 to 686 ppm and dramatically increase (i.e., ten times) for extracted solutions from monument samples, ranging from 5395 to 6880 ppm. The dominant cation is sodium while the dominant anion is chlorine. Acid insoluble residue analysis shows that the carbonate content ranges from 89.2% to 96.4% for fresh samples from quarries and from 9.2% to 94.8% for weathered monument samples. The weight loss of the quarry oolitic limestone samples range from 30.7% to 32.7% and its physical and mechanical properties become worse after being subjected to 15 cycles of a durability simulation soundness test (using a sodium sulphate solution). Our main recommendations are to use suitable grouting for binding the cracks, high durability reconstruction rocks, and suitable cleaning methods to remove salts from the monuments. 相似文献
996.
The landscape fragmentation caused by road construction has many direct and indirect impacts on wildlife and ecosystems. By using the GIS and statistic software of fragmentation computation, a comprehensive index, road-induced landscape fragmentation index (RLFI), is proposed to quantify the degree of landscape fragmentation resulting from different levels of road constructions. The results show that road-induced fragmentation index in China ranges from 0.987 to 3.357, with a mean of 1.846 in 2002. The regional differences of landscape fragmentation are obvious and scoring sequence is: North China (2.65) > East China (2.62) > Central China (2.60) > South China (2.51) > Southwest China (2.34) > Northeast China (2.19) > Inner Mongolia (1.88) > Northwest China (1.67) > Qinghai-Tibet Plateau (1.65). The anisotropic analysis indicates that the variation of fragmentation index in east-west direction is larger than that in south-north direction. 相似文献
997.
中国的公路建设与景观破碎程度 总被引:1,自引:0,他引:1
The phenomenon of habitat fragmentation which was resulted from anthropogenic disturbances for natural landscape or ecosystems such as removing original land cover, creating edge habitat, altering landscape structure and function, and increasing access fo… 相似文献
998.
DONA J. STEWART 《Geographical review》2005,95(3):400-424
ABSTRACT. In pursuit of its foreign‐policy goals, the administration of President George W. Bush has attempted a dramatic reshaping of the vision of the Middle East in the American mind. References to the “new” or “greater” Middle East now include countries far outside traditional concepts of the region, including those in West Africa, Southeast Asia, and Central Asia. The administration argues that this region is defined not by cultural (Arab) or religious (Islam) characteristics but by a lack of democracy; hence a grand strategy is needed to execute reform. This article examines current U.S. efforts to achieve reform in the region, the components of the ideological construction of the New Middle East, the perceived role of Iraq, Turkey's potential role as a “model” for the region, and responses from the region to current U.S.‐led reform efforts. 相似文献
999.
陈君 《中国地质灾害与防治学报》2001,12(1):67-70
文章以湖北省襄-十高速公路襄樊至武当山段为例,提出了建设用地地质灾害危险性评估范围、评估重点的确定方法,就地质灾害危险性的涵义展开讨论并给出了明确定义。结合工程实践,对现状评估、预测评估与综合评估的要点、方法展开论述,提出高速公路地质灾害危险性等级划分标准,同时提出以防灾工程投入比大小评估建设用地土地适宜性的量化指标,并对存在的主要问题提出相应建议。 相似文献
1000.
M. G. Winter 《Engineering Geology》2001,60(1-4):285-294
Spent oil shale (or blaes) is a potentially valuable engineering material and is present in large quantities in the West Lothian area of Scotland. It can be used successfully as general fill or capping layer. However, due to its high quality it may be more suited to use as selected granular fill or sub-base. In particular, cement stabilisation will reduce frost susceptibility and may be a particularly appropriate outlet for spent oil shale for use as sub-base. However, an increase in control and testing may be required, having an effect on the cost of using such materials. Conditions under which spent oil shale should not be used are also identified. 相似文献