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101.
102.
The Kwinana Coastal Fumigation Study: III – Meteorological and Turbulence Modelling on Selected Days
The Kwinana Coastal Fumigation Study took place inearly 1995 at Kwinana near Perth in Western Australia.The study involved surface and elevated meteorologicaland plume fumigation measurements in sea-breeze flowsnear the coast, and has yielded a comprehensive dataset that is suitable for assessing meteorological andplume dispersion models. In this paper, wesimulate the meteorology and turbulence on four casestudy days, and compare model results with thedetailed surface and aircraft measurements takenduring the study. These days had surface synopticwinds ranging from southerly to northeasterly, witheither stable or near-neutral temperature profilesover the sea.The model used was based on that developed by Hurley(Boundary-Layer Meteorol.
83, 43–73, 1997), but extended here to allow domain nesting,optional non-hydrostatic simulations, and a vegetativecanopy at the surface. The model was forced bystandard weather service synoptic data, and thesimulations have captured the essential features ofthe strong sea-breeze circulation observed on thesedays. The boundary-layer structure over the sea waspredicted to be near-neutral or stable in agreementwith the observations on the particular day. The windspeed and direction in the sea-breeze flow weregenerally predicted well, although the predictedmaximum inflow speed over the land was a little toohigh. The potential temperature was generallyover-predicted, but temperature gradients agreed well.Predicted turbulence levels in the bottom-half of thethermal internal boundary layer compared well to theobservations, but under-estimated the observations inthe in the upper half of this layer. Near-surfacemeasurements of meteorological variables werepredicted well over the entire diurnal cycle, althoughthe predicted sea-breeze onset was generally tooearly. A quantitative model evaluation for thenear-surface sites showed the model performance to bebetter than that from other studies, with Index ofAgreement (IOA) values of 0.8 (wind speed) and 0.96(temperature), compared with values of 0.5–0.6 (windspeed) and 0.33 (temperature) obtained from otherstudies.The availability of new higher resolution synopticanalyses should obviate the lack of spatial andtemporal resolution in synoptic inputs. Theincorporation of these higher resolution synopticinputs and new parameterisation schemes should improvefuture model performance. 相似文献
103.
Eight periods of relativistic electron precipitation (REP) with electron energies of more than 300 keV are identified from VLF data (10/14 kHz) monitored along the Aldra (Norway) / Apatity (Kola peninsula) radio trace. In these cases, anomalous ionization below 55/50 km occurred without disturbing the higher layers of the ionosphere. The daily total ozone values in Murmansk for six days before and six days after the REP events are compared. In seven of eight events a decrease in the total ozone of about 20 DU is observed. In one event of 25 March, 1986, the mean total ozone value for six days before the REP is bigger han that for six days after, but this a case of an extremely high ozone increase (144 DU during the six days). However, on days 3 and 4 there was a minimum of about 47 DU with regard to REP days, so this case also confirms the concept of the ozone decrease after REP. The difference between mean ozone values for periods six days before and six days after the REPs was found also for 23 points in Arctic on TOMS data. The difference was negative only in Murmansk longitudinal sector. Along the meridian of the trace it was negative at high latitudes in both hemispheres and was near zero at low latitudes. 相似文献
104.
A Lagrangian technique is developed and applied to calculate stratosphere-troposphere exchange in an extratropical cyclone. This exchange is computed from the potential vorticity or PV along trajectories, calculated from ECMWF circulation data. Special emphasis is put on the statistical significance of the results. The computed field of the cross-tropopause flux is dominated by elongated patterns of statistically significant large downward and small upward fluxes. The downward fluxes mainly occur in the lower part of the considered tropopause folds. The upward fluxes are found near the entrance of the folds, in the tropopause ridges. The ratio between the area averaged downward and upward cross-tropopause fluxes increases with increasing strength of the cyclone. Since the largest fluxes are shown to occur in the regions with the largest wind shear, where PV-mixing is thought to cause large cross-tropopause fluxes, the results are expected to be reliable, at least in a qualitative sense. The position of a tropopause fold along the northwest coast of Africa is confirmed by total ozone observations. The results indicate that the applied Lagrangian technique is an appropriate tool for diagnosing stratosphere-troposphere exchange. 相似文献
105.
106.
中尺度自动气象站故障维护与分析 总被引:9,自引:6,他引:3
针对中尺度自动气象站的构成以及出现的故障现象、故障原因等进行分析,提出故障维护的具体方法与措施,以提高中尺度自动气象设备运行能力。 相似文献
107.
气象海况是组织海上油田生产的重要依据,通过查询海区历史气象资料,分析研究埕岛油田海域的气象规律和特点,紧密结合油田区城地理、海上施工及平台、船舶等设施及装备的基本情况,针对油田生产、海上施工等受气象水文因素制约、影响的不同特点,提出科学的组织生产措施,提高生产效率,保障安全生产。 相似文献
108.
为了提高辽宁省高速公路的气象保障服务能力,提出了建立辽宁高速公路气象保障服务系统的设想。分析了辽宁及国内外的高速公路气象保障的研究概况,在此基础上,根据高速公路管理部门对于气象保障服务的实际需求,认为建立高速公路气象保障服务系统应合理布设和增加高速公路沿线的自动气象监测站点,要以气象部门信息网络为依托,以气象数据库、预报技术平台、预报技术方法为基础,有针对性地开发高速公路气象预报预警模式和决策系统,并提出了建立高速公路信息反馈及损毁评估平台的设想,试图为提高高速公路气象服务水平提供技术支撑。 相似文献
109.
青藏高原气象学的研究进展和问题 总被引:25,自引:1,他引:25
分高原天气学、高原气候学、高原及邻近地区的大气环流、以及高原数值预报和模拟四方面简要回顾了新中国成立以来我国(也兼及国外)青藏高原气象学的主要进展,也提出今后研究中应注意的有关问题。 相似文献
110.
回顾了湿空气热动力学的研究进展,对未饱和湿大气、饱和湿大气及非均匀饱和湿大气的动热力方程、能量方程、连续方程等进行了梳理,指出饱和湿空气动量方程与非均匀饱和湿空气动量方程的最大区别在于对凝结过程的处理不同。饱和湿大气中,由于大气均是饱和的,由饱和造成的水凝物可处处出现,不能区分真正发生水汽凝结的区域。而非均匀饱和湿空气中,凝结发生与相对湿度的幂次方有关(即与凝结概率函数的分布有关),在相对湿度较小的区域不会出现水汽凝结,凝结区与非凝结区可自动区别,其描述的凝结过程与实际大气更接近。同时,总结了湿大气水汽凝结饱和非均匀分布的动热力物理量在高影响天气分析中的应用,最后讨论了未来推进湿空气动力学研究需重点考虑的一个内容。 相似文献