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941.
成都地区雷暴的天气气候特征 总被引:5,自引:0,他引:5
利用1986~2000年成都地区的雷暴资料,分析得到:成都地区的多年平均雷暴日数在2430之间,属雷暴较多的地区之一。季节性显著,冬季无雷暴,盛夏雷暴日数占全年雷暴日数的2/3左右。地域性强,大城市的热岛效应对雷暴的发生有促进作用。雷暴天气过程的分析为作好雷暴发生时空域预报提供了好的思路。 相似文献
942.
介绍了“九五”期间建设的我国第三代数字化形变台网技术系统的构成、观测仪器的性能指标及台站的分布,剖析了数字化形变台站的数据流程、功能界面与使用数据采集器的基本要求。数字化台网2001—2004年基本运行情况为:台网的130台(套)数字化形变仪器(除1套外)皆已投入监测并产出连续观测资料.其中.90%以上达到Ⅰ类标准,这些结果反映了数字化形变台网良好的监测运行情况。 相似文献
943.
CHENJie 《中国地理科学(英文版)》2004,14(3):227-238
Rapid urbanization and growing size of cities will have an increasing impact on the global environment in the 21st century. As an engine of urban development to drive economic growth and technological innovations, industry has moved its focus from controlling environmental hazards to stimulating sustainable industrial development throughout the entire product lifecycle. These process- and technology-driven innovations for industrial production are prerequisites for enhancement of urban environment and sustainable development of cities. In this review, problems of environment and resources scarcity associated with rapid urbanization are demonstrated. And, on the basis of expatiations on the concepts and policies of the cleaner production (CP) and other similar initiatives with the goal of preventing pollution at the source and of managing the raw material more efficiently, two different ways to link the practice of cleaner production in industrial sector with performance of urban environment are discussed in detail. Then, the introduction, practice and legislation of CP strategies in China are outlined, and possibility for China to develop CPC (Cleaner Practices for Cities) approaches in the demonstration cities is discussed. Finally, some suggestions on implementation of CPC strategies are put forward. 相似文献
944.
YANMin-hua DENGWei CHENPan-qin LIANGLi-qiao 《中国地理科学(英文版)》2004,14(4):320-325
The characteristics of zonal anomaly and change rule of temporal distribution of annual precipitation in the northeastern China are revealed in this paper with EOF (Empirical Orthogonal Function) and REOF (Rotated Empirical Orthogonal Function) methods and results are drawn in the standard relief maps with GIS technology for practical application. Data used in the study were obtained from 208 meteorological stations over the northeastern China from 1961 to 2001. EOF results show that the first 3 loading vectors could give entire spatial anomaly structure of annual precipitation. In the Northeast Plain including the Songneng Plain and the Liaohe Plain, there is a regional compatibility (whether wet or dry) of annual precipitation change and this precipitation pattern has occurred since the late 1980s to the present. There also exist annual precipitation patterns of wet (or dry) in south and dry (or wet) in north and wet (or dry) in east and dry (or wet) in west. REOF results display 8 principal precipitation anomaly areas by the first 8 rotated loading vectors: the west plain, the Liaodong hills, the Sanjiang Plain, the Liaoxi hills,the Changbai Mountains, the Hulun Buir Plateau, the southwest plateau and the Liaodong Peninsula. 相似文献
945.
946.
Hydrological character and Sea-current profiles structure are studied andanalyzed in sea-area of the front of Amery Ice Shelf,Prydz Bay with LADCP,CTDdata.These LADCP,CTD data were acquired during the 19th Chinese Antarctic Sci-entific Expedition.Results of this study agree with that,there exist four differentkinds of water masses in the area of the front of Amery Ice Shelf in the summer of Ant-arctica.Current distribution presents a semi-circumfluence which flows in at the eastand flows out in the west.Moreover,clockwise and anti-clockwise vortices werefound in upper layer and mid-layer in the Prydz Bay.Western areas of these anti-clockwise vortices are positions of inflows from Prydz Bay to Amery Ice Shelf.Thesource of these inflows is the coastal westward current originated in the east of PrydzBay.All these characteristics come down to the pattern of circumfluence,ice meltrate under Ice Shelf,scale of Ice Shelf water production and form of water exchangesbetween area of Ice Shelf and area of Prydz Bay. 相似文献
947.
The phytoplankton reproduction capacity (PRC), as a new concept regarding chlorophyll-a and primary production (PP) is described. PRC is different from PP, carbon assimilation number (CAN) or photosynthetic rate ( P^B ) . PRC quantifies phytoplankton growth with a special consideration of the effect of seawater temperature. Observation data in Jiaozhou Bay, Qingdao, China, collected from May 1991 to February 1994 were used to analyze the horizontal distribution and seasonal variation of the PRC in Jiaozhou Bay in order to determine the characteristics, dynamic cycles and trends of phytoplankton growth in Jiaozhou Bay; and to develop a corresponding dynamic model of seawater temperature vs. PRC. Simulation curves showed that seawater temperature has a dual function of limiting and enhancing PRC. PRC‘s periodicity and fluctuation are similar to those of the seawater temperature. Nutrient silicon in Jiaozhou Bay satisfies phytoplankton growth from June 7 to November 3. When nutrients N, P and Si satisfy the phytoplankton growth and solar irradiation is sufficient, the PRC would reflect the influence of seawater temperature on phytoplankton growth. Moreover, the result quantitatively explains the scenario of one-peak or two-peak phytoplankton reproduction in Jiaozhou Bay, and also quantitatively elucidates the internal mechanism of the one- or two-peak phytoplankton reproduction in the global marine areas. 相似文献
948.
Sediment-water fluxes of N and P species in the Bohai Sea were investigated in September-October 1998 and April-May 1999. The benthic fluxes of nutrient species were determined by incubating sediment core samples with bottom seawater bubbled with air or nitrogen. NO^-2,NH4, dissolved organic nitrogen (DON) and phosphorus (DOP), total dissolved nitrogen (TDN) and phosphorus (TDP), and PO4^3- showed a net exchange flux from seawater to sediment, while NO^-3, dissolved inorganic nitrogen (DIN) and SiO3^2- were released from sediment to seawater in the Bohai Sea. Sediment-water nutrient exchange increases DIN and reduces the phosphorus load in the Bohai Sea. The release of silicate from sediment to overlying seawater reduces potential silicate limitation of primary production resulted from decrease of riverine discharge.The exchange flux of nutrients showed no obvious seasonal variation. The present study showed that the concentrations and composition of nutrients in the water column were affected by suspended sediment, and that not all the exchangeable phosphate in sediment could be released via sediment resuspension. 相似文献
949.
1 IntroductionBacteriaandtheiractivitiesplayanimportantroleintheelementalbiogeochemicalcyclesandenergytransformingintheocean (Zhenetal.1 997) .DortchandPackard(1 989) proposedthatfoodwebsintheeutrophicwatersaredominatedbythebiomassofprimaryproducerswhilefoodwebsintheoligotrophicwatersaredominatedbythebiomassofmicrobes.Heterotrophicbacteriahadbeenshowntoplayanimportantroleinthedecompositionoflarge ,rapidlysinkingorganicparticleswithinandbelowtheeuphot iczone ,andfurthertoaffecttheelementaldyn… 相似文献
950.
1 IntroductionHydrophobically modified water-soluble polymers,also known as hydrophobized polymers, are thosemodified by hydrophobic groups such as alkyl,arolkyl, and deoxycholic acid. In water, they canself-aggregate due to their intro- and/or intermolecularhydrophobic interaction. By this process, unique hy-drogel nanoparticles with hydrophobic core and hy-drophilic shell can be prepared, which is a new ap-proach to preparing the monodispersed hydrogelnanoparticles (Whitesides et al., 1991; … 相似文献