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991.
回顾了国内外智能旅游信息系统及其关键技术研发现状,总结了旅游信息系统的两种开发建设模式——以智能信息技术和通信技术为核心的智能旅游信息系统和以GIS为基础开发的旅游地理信息系统,设计了一种基于GIS,GPS和智能技术的智能旅游信息系统平台,研究了实时环境数据感知和协同处理技术、智能分析与服务技术等相关关键技术的实现方法,以苏州市国家4A和5A级风景区为应用案例,开展应用示范。  相似文献   
992.
测量了不同浓度LiBO2溶液分别在298.15和323.15 K的密度、电导和pH,通过测得的pH和硼酸根离子化学平衡常数计算得到溶液中硼酸根离子的物种分布。根据获得的物种分布结果,推测溶液中各硼酸根离子之间的相互转化过程,并分别用偏摩尔体积公式和Onsager方程对溶液偏摩尔体积及摩尔电导率进行计算并拟合。对计算得到偏摩尔体积值和极限摩尔电导率值与文献报道的数据进行对比,计算结果与文献报道值吻合较好。  相似文献   
993.
澜沧江流域农业灌溉需水的时空变化(英文)   总被引:1,自引:0,他引:1  
Based on the data of eight meteorological stations from the 1950s to 2007, current cropping patterns, field water moisture management, we use the Mann-Kendall and the Re-scaled Range Analysis methods to research the changes of humidity and crop irrigation water requirements in the Lancang River Basin. The results show that the annual and dry season average temperatures significantly increased, and the dry season rainfall increased while wet season rainfall decreased. Evaportranspiration (ET0) increased during both dry and wet seasons at all stations except Dali, Jianchuan and Gengma, and the aridity-humidity index decreased at most of the stations. The turning points of weather factors, ET0, the arid-ity-humidity index, paddy irrigation requirements and total agricultural water requirements occurred from the 1960s to the 1990s. The spatial changing tendency of paddy irrigation quota increased with the increase of altitude and latitude, and the correlation coefficients are 0.513 and 0.610, respectively. The maximum value is observed in Weixi, while the minimum in Mengla.  相似文献   
994.
干旱程度对C3植物红砂和C4植物珍珠光合生理参数的影响   总被引:2,自引:1,他引:1  
严巧娣  苏培玺  高松 《中国沙漠》2012,32(2):364-371
 C3和C4植物混生在草地生态系统中较多,而在荒漠生态系统少见。在中国荒漠地区,C3小灌木红砂和C4半灌木珍珠在特定生境下混生在一起,以独特方式适应高温强光和干旱的极端环境。通过在不同干旱程度下测定它们生长期叶片的光合气体交换参数,探讨它们在混生条件下对极端环境的生理响应特征。结果表明,红砂的净光合速率(Pn)、蒸腾速率(E)、气孔导度(Gs)均要高于珍珠;而珍珠的水分利用效率(WUE)则要高于红砂。这表明珍珠和红砂在水分匮乏的荒漠生境下采取了不同的生存策略。红砂通过维持较高净光合速率和较高蒸腾速率来生存;而珍珠则通过高水分利用效率生存。  相似文献   
995.
从影响因素角度用LMDI分解方法对新疆1999—2009年的碳排放进行研究。结果表明:能源结构和能源强度对新疆人均碳排放增长起抑制效应,且能源强度的抑制效应大于能源结构的抑制效应;产业规模和人口规模对新疆人均碳排放增长起拉动效应,且产业规模的拉动效应大于人口规模的拉动效应。能源强度和能源结构的抑制效应难以抵消由产业规模和人口规模拉动的新疆人均碳排放的增长。在实证研究结果的基础上提出了相应的政策建议。  相似文献   
996.
中国建设用地变化的空间分异特征   总被引:2,自引:0,他引:2  
采用变异系数、希尔指数与空间自相关方法对我国2002—2008年建设用地变化的区域差异及空间相关性进行了探讨。结果显示:(1)2002—2008年我国区域建设用地的变化差异总体上呈减小趋势,但区域差异仍较为明显。(2)我国区域建设用地的增长呈现明显的空间二元结构,东部地区"高高"聚集,西部地区"低低"聚集。当前我国土地利用处于"倒U"型变化曲线的顶部区域,土地利用的压力依然很大,应根据土地利用变化的差异性及空间相关性,科学地制定区域土地供给政策。  相似文献   
997.
城市空间形态变化研究涉及到自然条件、资源分布、人类活动、社会经济发展等诸多方面,运用层次分析法对复杂因素构成的整体问题进行层次分解和重新构造,建立多目标的综合评价指标体系和模型。以西昌市为例,将影响城市化发展和空间形态发展变化的特征因子概括分解为自然因子和人类活动因子两大类,并基于DEM数据分别提取出坡度、相对高程、坡向、地面粗糙度数据,利用两个不同时期的遥感数据求取出土地变化率数据,从而作为分析西昌市空间形态变化特征的驱动力因子。结合层次分析法计算出来的5个因子权重值,在ArcGIS 9.3中利用栅格计算器进行叠置分析,求取出西昌市空间形态变化模式趋势图和空间发展模式分类图。  相似文献   
998.
This paper assesses future climate changes over East and South Asia using a regional climate model (RegCM4) with a 50?km spatial resolution. To evaluate the model performance, RegCM4 is driven with ??perfect boundary forcing?? from the reanalysis data during 1970?C1999 to simulate the present day climate. The model performs well in reproducing not only the mean climate and seasonality but also most of the chosen indicators of climate extremes. Future climate changes are evaluated based on two experiments driven with boundary forcing from the European-Hamburg general climate model (ECHAM5), one for the present (1970?C1999) and one for the SRES A1B future scenario (2070?C2099). The model predicts an annual temperature increase of about 3°?C5° (smaller over the ocean and larger over the land), and an increase of annual precipitation over most of China north of 30°N and a decrease or little change in the rest of China, India and Indochina. For temperature-related extreme indicators in the future, the model predicts a generally longer growing season, more hot days in summer, and less frost days in winter. For precipitation-related extremes, the number of days with more than 10?mm of rainfall is predicted to increase north of 30°N and decrease in the south, and the maximum five-day rainfall amount and daily intensity will increase across the whole model domain. In addition, the maximum number of consecutive dry days is predicted to increase over most of the model domain, south of 40°N. Most of the Yangtze River Basin in China stands out as ??hotspots?? of extreme precipitation changes, with the strongest increases of daily rain intensity, maximum five-day rain amount, and the number of consecutive dry days, suggesting increased risks of both floods and droughts.  相似文献   
999.
A number of indices have been employed to describe weather extremes on the basis of climate regimes and public concerns. In this study, we combined these traditional indices into four groups according to whether they relate to warm (Twarm), cold (Tcold), wet (Pwet), or dry (Pdry) extremes. Analysis of the combined indices calculated for the daily temperatures and precipitation at 750 meteorological stations in Korea, China, and Japan for 1960s?C2000s shows increasing trends in Twarm and Pdry events and decreasing trends in Tcold events in recent decades, particularly in the northern part of East Asia. A notable regional variation is an increase in the Pwet events in the Korean Peninsula. We applied the same analysis to a 200-year global climate model simulation for 1900?C2099 using the National Center for Atmospheric Research-Community Climate System Model 3. During the 20th century, the changes in Twarm and Tcold calculated from the model data are largely consistent with those calculated from the observations, especially in northern East Asia. The model projections for the 21st century indicate statistically significant increasing Twarm and decreasing Tcold trends in extreme events over the region. Results obtained from historical archives and model simulations using our combined weather extreme indices suggest that northern East Asia will be subject to increased warm and dry extremes and the Korea Peninsula will experience more wet extremes.  相似文献   
1000.
By comparing two sets of quality-controlled daily temperature observation data with and without the inhomogeneity test and adjustment from 654 stations in China during 1956-2004 and 1956-2010, impacts of inhomogeneity on changing trends of four percentile temperature extreme indices, including occurrences of cold days, cold nights, warm days, and warm nights with varying intensities, were discussed. It is found that the inhomogeneity affected the long-term trends averaged over extensive regions limitedly. In order to minimize the inhomogeneity impact, the 83 stations identified with obvious inhomogeneity impacts were removed, and an updated analysis of changing trends of the four temperature extreme indices with varying intensities during 1956-2010 was conducted. The results show that annual occurrences of both cold nights and cold days decreased greatly while those of warm nights and warm days increased significantly during the recent 20 years. The more extreme the event is, the greater the magnitude of changing trends for the temperature extreme index is. An obvious increasing trend was observed in annual occurrences of cold days and cold nights in the recent four years. The magnitude of changing trends of warm extreme indices was greater than that of cold extreme indices, and it was greater in northern China than in southern China. Trends for summer occurrence of cold days were not significant. Decreasing trends of occurrences of both cold nights and cold days were the greatest in December, January, and February (DJF) but the least in June, July, and August (JJA), while increasing trends of warm nights were the greatest in JJA. Cold nights significantly decreased from 1956 to 1990, and then the decreasing trend considerably weakened. The decreasing trend also showed an obvious slowdown in recent years for occurrence of cold days. However, increasing trends of warm nights and warm days both have been accelerated continuously since the recent decades. Further analysis presents that the evolution of the trends for occurrences of the four temperature extreme indices was dominated by the changes in northern China.  相似文献   
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