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71.
本文利用一个已发展的陆面过程参数化方案与大气边界层模式耦合,模拟了半干旱区绿洲戈壁非均匀下垫面的陆面过程及其与大气边界层的相互作用,给出了“绿洲效应”这一自然现象垂直剖面上更为清晰、准确和细致的结构特征.数值模拟的结果与早前的许多观测实验结论相吻合,即“绿洲效应”具有明显的“冷岛效应”和“湿岛效应”;它表现为在绿洲区域比戈壁沙漠区域环境温度低、湿度大、湍流动能输送弱,具有下沉气流而导致与周围戈壁沙漠区域产生水平输送环流.而更加细致地研究这些现象对于深入了解绿洲气候的形成和绿洲的维持机理具有重要的意义. 相似文献
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This paper reports a geomorphologic landscape investigation, vegetation survey and soil sampling at 14 sites across the Gurbantunggut Desert between 87°37′09"-88°24′04"E and 44°14′04"-45°41′52′Nl. The study encountered 8 species of low trees and shrubs, 5 of perennial herbs, 8of annual plants and 48 of ephemeral and ephemeroid plants. These species of plants represent one-third of the species found in the Gurbantunggut Desert, and their communities make up a large proportion of desert vegetation with great landscape significance. In the investigation we found that the plant communities are accordingly succeeded with the spatial variation of macro-ecoenvironment.Using Principal Component Analysis (PCA) and Correlation Analysis (CA) we found that the micro-ecoenvironment heterogeneity of aeolian sandy soil′s physical and chemical properties such as soil nutrient, soil moisture, soil salt, pH etc. only impacted the diversity of herb synusia (PIEherb) of the desert, with a negative correlation. Meanwhile, the impact of microhabitat on the plant community pattern with an antagonistic interaction made vegetation′s eco-distribution in a temporary equilibrium. 相似文献
74.
阿拉善沙漠湿沙层水分来源同位素示踪 总被引:2,自引:0,他引:2
为弄清阿拉善沙漠湿沙层的水分来源,在该地区进行了人工模拟降水入渗的示踪试验。模拟单次降水量为59 mm,观察剖面最大入渗深度仅为46 cm,这一结果表明该地区的降水几乎不能通过沙层入渗到地下水中。对4个沙丘湿沙层剖面中不同深度的含水率、Cl-、δD与δ18O进行了分析,数据显示在蒸发能力极强的阿拉善地区,地下水是以薄膜水的形式,通过蒸发、凝结向地表运动,最终蒸发排泄。泉水、井水、湖水与土壤水中的同位素特征表明具有相同的补给源,均来自于地下水。推断横穿阿拉善地块的杂多-雅布赖断裂带与狼山-日喀则断裂带中可能存在地下水深循环通道,青藏高原河流、湖泊的渗漏水可能是阿拉善地下水的主要补给源。 相似文献
75.
任雅宁 《华北地质矿产杂志》2014,(1):49-50
内蒙古阿拉善沙漠世界地质公园位于内蒙古自治区阿拉善盟境内,东倚贺兰山,南接祁连山,西达黑河,北部有结构洼地与外蒙为界。该公园以其特殊的地理位置、地质构造、生态环境和气候条件,形成了以沙漠、戈壁为主体的地貌景观,是中国唯一的沙漠地质公园。并于首届中国地质公园“选美”活动中获得“中国最美地质公园”的称号。 相似文献
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YANG Zisheng LIU Yansui BAO Guangjing LI Zhiguo HE Yimei 《山地科学学报》2006,3(3):237-246
The rocky desert in a karst area directly causes the lack of soil, water and forest, hence leading to the poverty there. In 1990, the villagers from the Muzhe Village in Benggu Township, Xichou County, Yunnan declared a war against rocky desert in an attempt to ask the fields for more yields. They invented a distinctive land rehabilitation and sustainable use pattern called "transforming heaven and earth" that had been practiced in Southwest China's karst areas. The key mechanism of the pattern was to develop terraced fields with well conserved soil, water and fertility by exploding rocks in the fields, building stone walls, gathering more soil, and improving soil quality and productivity for the fields in combination with building of irrigation facilities and roads, as well as with forestation and agriculture structure adjustment. The purpose of the pattern was to alleviate poverty in the karst areas by improving soil productivity and promoting agricultural development. A typical area was studied with the help of Participatory Rural Appraisal (PRA) and the pattern was carried out there for fifteen years, have produced excellent ecological benefits and good economic benefits. Its application in the area approved that it was a sustainable land use pattern for rocky desert areas. 相似文献
78.
有绚丽夺目的色彩,有从沙漠到山地森林,有从潮湿的土壤到干燥的岩石,有在人迹罕至的悬崖绝壁上,有的爬在整个树干的基部,有的挂在树枝上,还有的为岩石披上了一层绿装,更多的是紧贴大地,它们就是植物世界中的——地衣。 相似文献
79.
TANGYa XIEJiasui SUNHui 《山地科学学报》2004,1(1):38-45
Dry valleys are a striking geographic landscape in Hengduan Mountains Region and are characterized by low rainfall, desert type of vegetation and fragile environment. Past efforts and resources have been concentrated mainly on rehabilitation of degraded ecosystem and fragile environment, particularly reforestation, while socio-economic development has been largely overlooked. Despite successes in pocket areas, the overall trend of unsustainability and environmental deterioration are continuing. It is important to understand that uplift of the Tibetan Plateau is the root cause of development of dry valleys, and development and formation of dry valleys is a natural process. Human intervention has played a secondary role in development of dry valleys and degradation of dry valleys though human intervention in many cases has speeded up environmental degradation of the dry valleys. It is important to understand that dry valleys are climatic enclaves and an integrated approach that combines rehabilitation of degraded ecosystems and socio-economic development should be adopted if the overall goal of sustainable development of dry valleys is to be achieved. Promotion of niche-based cash crops, rural energy including hydropower, solar energy, biogas and fuelwood plantation is recommended as the priority activities. 相似文献
80.
HEIFE绿洲和沙漠地区大气边界层湍流混沌特性研究 总被引:8,自引:1,他引:7
利用“黑河实验”期间张掖、沙漠观测站加强观测期间1991年6月20日09:00至1991年10月2日09:00时段内水平风速的观测资料,计算分析了有关测量混沌的特征量:关联维数。Lyapunov指数和Kolmogorow熵。 相似文献