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81.
生态地理区域系统的比较研究   总被引:18,自引:2,他引:16  
吴绍洪  杨勤业  郑度 《地理学报》2003,58(5):686-694
生态地理区域系统通过对代表自然界宏观生态系统的生物和非生物要素地理相关性的比较研究和综合分析,按照自然界的地理地带分异规律,划分或合并而形成不同等级的区域系统。用中国的研究与国外同类研究的比较,可以拓宽这一领域的思路,便于在这一领域与国外的学者使用相似的科学语言进行学术交流,使中国这一领域的研究走向世界。本文从生态地理区域系统的发展过程、等级单位、指标体系与表达方法,区域划分等方面将中国有代表性的生态地理区域系统与国外同类研究进行比较,认为中外的研究有许多共同之处,如目标、研究内容和服务对象与环境、生态、全球变化等联系在一起,其中与美国R. Bailey所划分的美国、北美和全球生态地理区域更为接近,在等级系统、指标体系、表达方式到划分结果有近似之处。地域的差异,指标使用的不同,制图过程和表达方式的差异造成了区域划分的差别,似可以通过野外实地生态类型的辨识来加以修订。  相似文献   
82.
已经观测到的气候变化影响是显著的、多方面的。各个领域和地区都存在有利和不利影响,但以不利影响为主,未来的气候变暖将会对中国的生态系统、农业以及水资源等部门和沿海地区产生重大的不利影响。采取适应措施可以减轻气候变化的不利影响,应将适应气候变化的行动逐步纳入国民经济和社会发展的中长期规划中。由于我国科学研究的相对不足和科学认识能力的局限,目前的气候变化影响评估方法和结果还存在很大的不确定性。应当加强区域适应气候变化的案例研究、扩大研究领域、加强极端天气、气候事件影响的研究,以降低影响评估的不确定性,并提出切实可行的适应对策。  相似文献   
83.
Flood loss analysis and quantitative risk assessment in China   总被引:9,自引:4,他引:5  
Risk assessment is a prerequisite for flood risk management. Practically, most of the decision making requires that the risks and costs of all risk mitigation options are evaluated in quantified terms. Therefore, a quantitative assessment of possible flood loss is very important, especially for emergency planning and pre-disaster preparedness. This paper presents a preliminary methodology and an operational approach for assessing the risk of flood loss to the population, crops, housing, and the economy at county level in China. The present work assesses the risk of loss for each element (people, crops, and so on) under low-, moderate-, and high-intensity flood using intensity-loss curves and loss rates based on historical flood data from 1990 to 2008. Results show that the counties with high flood risk are primarily located in North, East, Central, and South China, particularly in the lower reaches of rivers. On the other hand, the risk of most counties in the western region is generally lower than that of counties in the eastern region. However, for the entire country, the high-risk regions have both a substantial amount of rainfall and low terrain, making such regions highly prone to flooding. Moreover, these high-risk regions present both high population and wealth density.  相似文献   
84.
Chen  Fahu  Wu  Shaohong  Liu  Hongyan  Yang  Xiaoyan  Liu  Jianbao 《地理学报(英文版)》2022,32(9):1642-1653
Journal of Geographical Sciences - Physical geography, one of the branches of geography, is the basic discipline of geographic science. And it is the scientific foundation of ecology, environmental...  相似文献   
85.
Net primary productivity (NPP) is the structure and function of the ecosystem. NPP can most important index that represents the be simulated by dynamic global vegetation models (DGVM), which are designed to represent vegetation dynamics relative to environ- mental change. This study simulated the NPP of China's ecosystems based on the DGVM Integrated Biosphere Simulator (IBIS) with data on climate, soil, and topography. The appli- cability of IBIS in the NPP simulation of China's terrestrial ecosystems was verified first. Comparison with other relevant studies indicates that the range and mean value of simula- tions are generally within the limits of observations; the overall pattern and total annual NPP are close to the simulations conducted with other models. The simulations are also close to the NPP estimations based on remote sensing. Validation proved that IBIS can be utilized in the large-scale simulation of NPP in China's natural ecosystem. We then simulated NPP with climate change data from 1961 to 2005, when warming was particularly striking. The following are the results of the simulation. (1) Total NPP varied from 3.61 GtC/yr to 4.24 GtC/yr in the past 45 years and exhibited minimal significant linear increase or decrease. (2) Regional differences in the increase or decrease in NPP were large but exhibited an insignificant overall linear trend. NPP declined in most parts of eastern and central China, especially in the Loess Plateau. (3) Similar to the fluctuation law of annual NPP, seasonal NPP also displayed an insignificant increase or decrease; the trend line was within the general level. (4) The re- gional differences in seasonal NPP changes were large. NPP declined in spring, summer, and autumn in the Loess Plateau but increased in most parts of the Tibetan Plateau.  相似文献   
86.
黔西南卡林型金矿床中存在两种类型的有机质,一种为具较低反射率的原地藻类体,散布于金矿石和沉积围岩中,多呈层纹状或条带状平行于层理面产出;另一种为热解沥青/焦沥青,多呈微细粒状产于蚀变及矿化岩石中,尤其是高品位矿石中,与主阶段似碧玉状石英、含砷黄铁矿、毒砂紧密共生或伴生,或呈分散的粒状被主阶段和晚阶段的石英、方解石、雄黄等热液矿物包裹。沥青以含较高的与成矿密切相关的微量元素As(4.90%~7.88%)和S(大多为7.48%~15.24%)区别于原地有机质(不含As,S含量2.72%~7.18%)。金矿石热液矿物中常见气相CH4、气液两相CH4-H2O等烃类流体包裹体。古油藏沥青多见于二叠系生物礁碳酸盐岩的溶洞、孔隙、裂缝等开放空间中,或单独产出,或与热液方解石伴生,沥青多呈镶嵌结构,显示出高热演化程度的特点。岩相学证据显示,金矿床成矿流体是一种富含金属和碳氢化合物的油水不混溶的盆地流体,金与烃类有机质一起活化、迁移,并通过不同的沉淀和捕获机制成矿、成藏。  相似文献   
87.
1981-2010年气候变化对青藏高原实际蒸散的影响(英文)   总被引:1,自引:0,他引:1  
From 1981 to 2010,the effects of climate change on evapotranspiration of the alpine ecosystem and the regional difference of effects in the Tibetan Plateau(TP) were studied based on the Lund-Potsdam-Jena dynamic vegetation model and data from 80 meteorological stations.Changes in actual evapotranspiration(AET) and water balance in TP were analyzed.Over the last 30 years,climate change in TP was characterized by significantly increased temperature,slightly increased precipitation,and decreased potential evapotranspiration(PET),which was significant before 2000.AET exhibited increasing trends in most parts of TP.The difference between precipitation and AET decreased in the southeastern plateau and increased in the northwestern plateau.A decrease in atmospheric water demand will lead to a decreased trend in AET.However,AET in most regions increased because of increased precipitation.Increased precipitation was observed in 86% of the areas with increased AET,whereas decreased precipitation was observed in 73% of the areas with decreased AET.  相似文献   
88.
The study on relationship between eco-geographic environment (EGE) and regional development (RD) is of theoretical and practical significance to promote the comprehensive study on nature and human factors and regional coordination development. Based on the evaluation index system and models of EGE and RD, Quadrant Analysis Method (QAM) and the Coordination Degree and Coordinated Development Degree Model (CDCDDM) were applied to studying the relationship between EGE and RD in Xinjiang in this paper. The results show that Xinjiang can be divided into four type regions according to the relationship between EGE and RD, namely high coordination region (HCR), overloading development region (ODR), low coordination region (LCR) and potential development region (PDR). Most areas of Xinjiang belong to LCR which can not bear a larger population and support large-scale economic development. HCR, ODR and PDR, which are mainly distributed in piedmont oases and take basin as unit, should be focused on in the development of Xinjiang. The EGE has great influence on RD, and there is serious contradiction between them. Relevant suggestions on development strategies were put forward according to the character of different type regions, and the key regions of macro-layout of RD in Xinjiang were pointed out.  相似文献   
89.
Despite the well-documented effects of global climate change on terrestrial species’ ranges, eco-geographical regions as the regional scale of ecosystems have been poorly studied especially in China with diverse climate and ecosystems. Here we analyse the shift of temperature zones in eco-geographical study over China using projected future climate scenario. Projected climate data with high resolution during 1961–2080 were simulated using regional climate model of PRECIS. The number of days with mean daily temperature above 10℃ and the mean temperature of January are usually regarded as the principal criteria to indicate temperature zones, which are sensitive to climate change. Shifts due to future climate change were calculated by comparing the latitude of grid cells for the future borderline of one temperature zone with that for baseline period (1961–1990). Results indicated that the ranges of Tropical, Subtropical, Warm Temperate and Plateau Temperate Zones would be enlarged and the ranges of Cold Temperate, Temperate and Plateau Sub-cold Zones would be reduced. Cold Temperate Zone would probably disappear at late this century. North borderlines of temperature zones would shift northward under projected future climate change, especially in East China. Farthest shifts of the north boundaries of Plateau Temperate, Subtropical and Warm Temperate Zones would be 3.1°, 5.3° and 6.6° latitude respectively. Moreover, northward shift would be more notably in northern China as future temperature increased.  相似文献   
90.
利用CINRAD/CB雷达产品对通辽地区2007年11月19日一次降雪过程的分析得出:基本反射率因子产品清晰地反映了这次天气过程的开始、发展与结束,可以用来确定降水回波的移动以及未来的趋势;并且通过不同仰角产品的对比可以判断云层的高度、厚度及强度(0.5°仰角产品探测到的云范围要比1.5°、2.4°仰角产品所探测到的大,0.5°仰角产品探测到的云多为低层云系)。速度图产品能够判断大气中的冷暖平流、层结稳定性、某一高度层的风向风速,以及存在的低空急流。对降水过程的预测与监测提供了十分有利的科学依据。  相似文献   
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