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891.
892.
QIAO Yanxiao LI Miwen Remote Sensing Center of Hebei Province Huaizhong Rd. Shijiazhuang Hebei 《《地质学报》英文版》2000,74(2):334-338
The Taihang Mountains area is an area in North China where serious mudflow hazards take place frequently. The hazards often obstrust traffic and make it difficult to carry out conventional ground investigations of the mudflow hazards. This paper introduces the feasibility study of mudflow hazards by using Landsat-5TM data. The study has achieved a great success through adopting both the faint spectral enhancement technique for mudflow fans (or other depositional areas) and comprehensive study of the environmental background of pregnant mudflows. Thus, remote sensing as a fast, convenient, low-cost and effective technical method can be used to recognise the situation of mudflow hazards so that effective rescue can be provided. 相似文献
893.
江苏金坛新石器时代环境变迁研究 总被引:9,自引:0,他引:9
对江苏金坛三星村新石器遗址JS98T0820号探坑南壁剖面进行采磁,对样品帮了粒度、地球化学、孢粉、微体古生物(有孔虫和介形类)等环境替代指标的测定与分析,并据此初步研究和恢复了该区新石器时代古定变状况,得出以下几点认识:(10地球化学分析结果本区知全新世以来,气候有从暖湿向干冷变化的总趋势。(2)P2O5的含量在马家浜墓葬层和崧泽文化层可达生土层的5~6倍,充分反映了当时人类活动日益频繁,同时也 相似文献
894.
贵阳城市地域结构演变及其环境效应 总被引:9,自引:0,他引:9
从城市地域范围 (规模 )、经济社会结构、职能结构、形态结构等方面阐述了贵阳城市地域结构演变的基本特征、趋势 ,探讨了城市地域结构演变的驱动力因子 ,并对近代贵阳城市地域结构演变所带来的系列环境效应进行了分析评述 相似文献
895.
1 IntroductionPast Global Changes (PAGES) is one of the important IGBP (International Geo-Biosphere Program) core programs, of which the objectives are to obtain and interpret all kinds of palaeoclimate records, understand the history of environment and ecological change, and provide basic material and necessary test for the establishment and improvement of climate forecasting models. Because the research of climatic and environmental changes on short time scale is the key connection bet… 相似文献
896.
The relationships of population and forest trends 总被引:4,自引:0,他引:4
The relationship between national trends in forest area and population is reviewed at the global scale. Evidence of an inverse relationship is confirmed. The relationship, however, may have weakened in recent decades, and it has clearly undergone a reversal in some countries during the nineteenth to twentieth centuries. The theme of a changing relationship through time is thus developed, as is that of an asymmetrical relationship in the sense that the forest area is likely to stabilize before population. On the basis of modelling from the current demographic relationship, the global forest area should stabilize before the middle of the twenty-first century. 相似文献
897.
J. Escs C. L. Alados F. I. Pugnaire J. Puigdefbregas J. Emlen 《Journal of Arid Environments》2000,45(4):325
This paper investigates allocation of energy to mechanisms that generate and preserve architectural forms (i.e. developmental stability, complexity of branching patterns) and productivity (growth and reproduction) in response to environmental disturbances (i.e. grazing and resource availability). The statistical error in translational symmetry was used to detect random intra-individual variability during development. This can be thought of as a measure of developmental instability caused by stress. Additionally, we use changes in fractal complexity and shoot distribution of branch structures as an alternate indicator of stress. These methods were applied to Anthyllis cytisoides L., a semi-arid environment shrub, to ascertain the effect of grazing and slope exposure on developmental traits in a 2×2 factorial design. The results show that A. cytisoides maintains developmental stability at the expense of productivity. Anthyllis cytisoides was developmentally more stable when grazed and when on south-facing, as opposed to north-facing slopes. On the contrary, shoot length, leaf area, fractal dimension and reproductive-to-vegetative allocation ratio were larger in north- than in south-facing slopes. As a consequence, under extreme xeric conditions, shrub mortality increased in north-facing slopes, especially when not grazed. The removal of transpiring area and the reduction of plant competition favoured developmental stability and survival in grazed plants. Differences between grazed and ungrazed plants were most evident in more mesic (north-facing) areas. 相似文献
898.
George Towers 《The Professional geographer》2000,52(1):23-36
The grassroots environmental movement often protests locally unwanted land uses. Many grassroots groups have, however, expanded their agenda to the scale of environmental justice. Explanations for this scale transformation include historical circumstances, individuals' radicalization through activism, and the growth of environmental justice networks. This case study, grassroots environmentalists' opposition to a proposed electricity transmission line in Monroe County, WV, explores another explanation: appeals for environmental justice are also a strategic response to siting regulatory procedures. With concepts emerging from the political geography of scale, I interpret the Monroe Countians' efforts and show how their strategies link the grassroots scale with that of environmental justice. 相似文献
899.
900.