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991.
By the Volume of Fluid (VOF) rnultiphase flow model two-dimensional gravity currents with three phases including air are numerically simulated in this article. The necessity of consideration of turbulence effect for high Reynolds numbers is demonstrated quantitatively by LES (the Large Eddy Simulation) turbulence model. The gravity currents are simulated for h ≠ H as well as h= H, where h is the depth of the gravity current before the release and H is the depth of the in-truded fluid. Uprising of swell occurs when a current flows horizontally into another lighter one for h ≠ H. The problems under what condition the uprising of swell occurs and how long it takes are considered in this article. All the simulated results are in reasonable agreement with the experimental results available. 相似文献
992.
厦门西海域潮流泥沙状况与综合开发设想 总被引:2,自引:0,他引:2
本文根据厦门西海域现场潮流泥沙资料及整体物理模型试验成果,分析了该区的潮流,泥沙淤积特性,在此基础上提出了为改善港口通航条件及其综合开发的设想方案。 相似文献
993.
994.
电流型集成温度传感器的应用 总被引:2,自引:0,他引:2
蔡明华 《中国海洋大学学报(自然科学版)》1994,(Z2)
介绍AD590温度传感器的测温原理及其测量精度分析,据此设计一种防爆型温度变送器 相似文献
995.
996.
Kazuyuki Uehara Shin-Ichi Ito Hideo Miyake Ichiro Yasuda Yugo Shimizu Tomowo Watanabe 《Journal of Oceanography》2004,60(2):397-409
During November 2000–June 2002, both direct current measurements from deployment of a line of five moorings and repeated CTD
observations were conducted along the Oyashio Intensive observation line off Cape Erimo (OICE). All the moorings were installed
above the inshore-side slope of the Kuril-Kamchatka Trench. Before calculating the absolute volume transports, we compared
vertical velocity differences of relative geostrophic velocities with those of the measured velocities. Since both the vertical
velocity differences concerned with the middle three moorings were in good agreement, the flows above the continental slope
are considered to be in thermal wind balance. We therefore used the current meter data of these three moorings, selected among
all five moorings, to estimate the absolute volume transports of the Oyashio referred to the current meter data. As a result,
we estimated that the southwestward absolute volume transports in 0–1000 db are 0.5–12.8 × 106 m3/sec and the largest transport is obtained in winter, January 2001. The Oyashio absolute transports in January 2001, crossing
the OICE between 42°N and 41°15′ N from the surface to near the bottom above the continental slope, is estimated to be at
least 31 × 106 m3/sec.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
997.
Numerical Simulation for Refraction-Diffraction of Waves in Water of Slowly Varying Current and Topography 总被引:3,自引:0,他引:3
Hong Guangwen Feng Weibing Xia Qiyi Pan Shaohua
Professor Research Institute of Coastal Ocean Engineering Hohai University Xikang Road Nanjing
Senior Engineer Research Institute of Coastal Ocean Engineering Hohai University Xikang Road Nanjing 《中国海洋工程》1997,(4)
A new numerical finite difference iteration method for refraction-diffraction of waves in waterof slowly varying current and topography is developed in this paper.And corresponding theoretical modelincluding the dissipation term is briefly described,together with some analysis and comparison ofcomputational results of the model with measurements in a hydraulic scale model(Berkhoff et al.,1982).An example of practical use of the method is given,showing that the present model is useful to engineeringpractice. 相似文献
998.
Julio Gil 《Estuarine, Coastal and Shelf Science》2003,57(5-6):1139-1149
From September to December 1995, three hydrographic surveys were carried out in the eastern Cantabrian Sea (Bay of Biscay). Changes in the water masses pattern were examined to study the variability and main energetic features in the area. At the beginning of December, an intense Poleward Current (PC), which had come from Portuguese slopes, entered the eastern Cantabrian Sea. This current was the most energetic event in this area in winter. The PC waters increased temperature by about 2 °C (subsurface layers) and salinity by 0.2 (surface layers) in the pattern of water masses in the eastern Cantabrian Sea in winter. The core current was approximately 10 km width and 120 m depth and the water transport, estimated from geostrophic current profiles, was of about 1.3 Sv.A well-defined wavelike front with two significant ridges in the western and eastern sampling area, was observed. The variability and meandering flow of the PC were driven by dominantly baroclinic instabilities, which are due to strong vertical velocity shear. In this synoptic-scale system, the potential vorticity advection, the differential vorticity advection, and the geopotential tendency have shown to be the cause of the ageostrophic motion and the main baroclinic disturbances.One important consequence of the entrance of the PC in the eastern Cantabrian Sea was the profound effect on the pattern of nutrients. The current-induced stratification pattern drives the distribution of nutrients in the different layers and the instabilities and meandering pattern of the PC was an important mechanism of fertilisation offshore. 相似文献
999.
该文中数值模拟了黄、东海陆架区的四大天文潮及其潮致拉格朗日环流。运用“流速分解法”将线性三维分潮波问题化为一个分潮潮位及深度平均流的二维问题和一个流速垂向剖面问题求解。其二维问题的底摩擦系数由三维模式导出 ,所导得的线性底摩擦力公式更符合物理意义 ,且避免一般二维模式中底摩擦力的经验假定。结果表明 ,三维模式完全可以通过准二维方法求解 ,以避免一般三维问题的繁重计算 相似文献
1000.
Migration to deep water during diapause may contribute to the retention of several dominant oceanic calanoid copepod populations in eastern boundary current systems, where the mean flow of poleward undercurrents is in opposition to mean equatorward surface flow. The vertical distributions of Calanus pacificus late copepodid stages were measured at a 1200-m deep, open-ocean station in the Southern California Bight on 13 dates between April 2000 and March 2001 using a MOCNESS (multiple opening and closing net and environmental sensing system). Copepod vertical distribution was compared to the vertical position of the California Undercurrent. Diapausing C. pacificus were primarily found between 300 and 400 m at the beginning of the diapause season, in June and July, and between 250 and 350 at the end of the diapause season, in November and January. Depth distributions were broader from August to October, ranging from about 350 m to the maximum depth sampled, 1100 m, and the median depth of diapausing C. pacificus was deeper, up to 800-900 m, during this period. Maximal depths of diapausing C. pacificus, 1100-1000 m, were greater than have previously been reported. The mean depth of the California Undercurrent was 250 m, and its approximate depth range was 110-430 m. Diapausing C. pacificus CV were abundant in the California Undercurrent at the beginning and end of the diapause season, in June to July and late-November to January, suggesting that poleward transport of diapausing copepods in the California Undercurrent contributes to C. pacificus population retention in the California Current System. 相似文献