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651.
The five chemical associations ofheavy metals have been extracted continuously using the Tessier extracting method.Results show that Cu,Pb,Fe,Zn and Cr in the sediments are mainly distributed in residual fraction,while the major chemical association of Mn is carbonates.Carbonate heavy metals are converted into Fe-Mn oxides in autunm.And in the low tidal flat,after carbonates have changed into ionic heavy metals,some of the elements are transported to the overlying water,Cu,Pb,Fe and Mn have good correlations with each other,and Zn,Cr also show their similarity of chemical behavior in the sediments.  相似文献   
652.
对采用多种生物酶复合水解的方法开发鱼可溶性蛋白质及鱼油进行了综述,展示了鱼开发和利用的广阔前景。  相似文献   
653.
Y. Tang  J. Bi 《GeoJournal》1996,40(1-2):3-7
The relationship between water pollution and economic development, its regional differentiation and its temporal trend is analyzed. With the uneven distribution of water resources, the regional differentiation of water pollution in China is very obvious. Based on the index RSR (the ratio of sewage to runoff), water pollution can be divided into five grades across the whole country. Overall, water pollution is more serious in north and northeast China. On the other hand, economic development level is not the only factor associated with water pollution. As for temporal change, with current economic growth and urbanization, it is impossible that water quality in China will be improved in the near future.  相似文献   
654.
2004年9月川渝暴雨的中尺度分析   总被引:12,自引:1,他引:12  
段海霞  毕宝贵  陆维松 《气象》2006,32(5):74-79
采用多种常规和非常规资料对2004年9月3—6日形成川渝暴雨过程的中尺度对流系统及其发生发展的背景场进行分析后认为:(1)低涡切变线上不断发生发展的中-β尺度对流系统是造成此次强降水的主要原因;(2)高层强辐散与中、低层强辐合以及强上升运动可能为中尺度对流系统的发生发展提供了有利的动力背景;(3)水汽通量的强辐合以及对流不稳定条件的存在可能为中尺度对流系统的发生发展提供了有利的热力背景。  相似文献   
655.
Introduction to the TAC special issue: The RegCNET network   总被引:2,自引:0,他引:2  
Summary Fostering climate research in economically developing nations (EDNs) is especially important because the welfare and economies of these nations are particularly dependent on climate and its variability. A critical factor that undermines the advancement of research in EDNs is that many EDN scientists are confronted with scientific isolation and lack of exposure to state-of-the-art research methodologies. One of the means to ameliorate this problem is to build “south–south” (i.e. EDN–EDN) and “north–south” (i.e. EDN–EAN, or economically advanced nations) research partnerships, which become more effective when they are based on collaborative projects where the participants share their respective expertise. This is the central paradigm underlying the formation of the REGional Climate research NETwork, or RegCNET.  相似文献   
656.
MM5模式中城市冠层参数化方案的设计及其数值试验   总被引:15,自引:5,他引:15  
文中在综合国外一些较先进的中尺度模式城市作用参数化方案的基础上 ,从城市下垫面结构对城市边界层大气作用的物理机制及实际应用两方面出发 ,对城市下垫面结构和人为活动等因素对边界层结构的影响及中尺度模式中城市化作用的合理体现等问题进行了较全面的考虑 ,改进和设计出能够较全面、细致地描述城市结构对大气边界层动力、热力结构的影响 ,且适合中尺度模式结构特点的城市冠层参数化方案 (UCP) ,并实现了其与MM5模式的耦合。进行了耦合后的UCP方案及采用原城市作用方案的MM5模式对BECAPEX试验期间北京地区气象条件多重嵌套细尺度进行了模拟试验 ,并与观测结果对比 ,结果表明 :相比于MM 5模式中原有表示城市作用的参数化方案来讲 ,设计的UCP方案在很大程度上提高了MM 5模式对城市边界层热力和动力结构的模拟能力。  相似文献   
657.
桂西低品位微细粒型金矿石堆浸技术原则工艺已日趋完善。通过变一次性底垫为多次使用底垫;改变矿石筑堆方法;提高喷淋强度;变间歇性吸附为全天候吸附等技改措施,达到增强矿堆透水性,提高浸出率,缩短喷淋周期,降低生产成本,提高经济效益的目的。  相似文献   
658.
We present an analysis of climate change over Europe as simulated by a regional climate model (RCM) nested within time-slice atmospheric general circulation model (AGCM) experiments. Changes in mean and interannual variability are discussed for the 30-year period of 2071–2100 with respect to the present day period of 1961–1990 under forcing from the A2 and B2 IPCC emission scenarios. In both scenarios, the European region undergoes substantial warming in all seasons, in the range of 1–5.5°C, with the warming being 1–2°C lower in the B2 than in the A2 scenario. The spatial patterns of warming are similar in the two scenarios, with a maximum over eastern Europe in winter and over western and southern Europe in summer. The precipitation changes in the two scenarios also show similar spatial patterns. In winter, precipitation increases over most of Europe (except for the southern Mediterranean regions) due to increased storm activity and higher atmospheric water vapor loadings. In summer, a decrease in precipitation is found over most of western and southern Europe in response to a blocking-like anticyclonic circulation over the northeastern Atlantic which deflects summer storms northward. The precipitation changes in the intermediate seasons (spring and fall) are less pronounced than in winter and summer. Overall, the intensity of daily precipitation events predominantly increases, often also in regions where the mean precipitation decreases. Conversely the number of wet days decreases (leading to longer dry periods) except in the winter over western and central Europe. Cloudiness, snow cover and soil water content show predominant decreases, in many cases also in regions where precipitation increases. Interannual variability of both temperature and precipitation increases substantially in the summer and shows only small changes in the other seasons. A number of statistically significant regional trends are found throughout the scenario simulations, especially for temperature and for the A2 scenario. The results from the forcing AGCM simulations and the nested RCM simulations are generally consistent with each other at the broad scale. However, significant differences in the simulated surface climate changes are found between the two models in the summer, when local physics processes are more important. In addition, substantial fine scale detail in the RCM-produced change signal is found in response to local topographical and coastline features.  相似文献   
659.
660.
章淹  毕慕莹 《大气科学》1977,1(4):273-281
北太平洋700 mb环流形势具有相当鲜明的季节性与地域性特征.北太平洋的海、气相互作用是这些特征以及东亚季风形成的一个原因.从海、气相互作用的角度出发,对比分析北太平洋700 mb环流形势和海表温度距平的分布,可以看出:有些情况下,大气对海洋的影响比较明显;在另一些情况下,海洋对700 mb环流形势的影响较为明显.它们之间的矛盾与矛盾的主要方面是不断地、经常地在转化以及相互影响着.它们的转化、演变对我国副热带高压及旱涝天气的变化有一定的关系。  相似文献   
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