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691.
It has been shown that due to the small surface of crater lakes, temperature surveillance is a problem using meteorological satellites. This is particularly true for El Chichón surface lake because it's about one tenth of an AVHRR pixel at nadir. In order to guarantee at least one unmixed pixel in AVHRR data, it is necessary to use only AVHRR data from NOAA satellite passes as close as possible to the nadir for the period 1996–2006, therefore AVHRR data of El Chichón's crater lake were only used it they were cloudless and had scan angles close to nadir. The analysis of the time series data shows that lake surface temperature had annual maximum values (> 35 °C) during 1996 and 1997 then surface temperature decay with a negative exponential trend reaching a steady state of about 30 °C in the last years (2004–2006). A seasonal temperature variation between the dry (December to May) and the wet (June to November) seasons is also observed. Differences between nocturnal and midday temperatures indicate the influence of lake energy emission (including reflectance) at midday under a strong short-wave solar radiation. Water surface radiative flux under these conditions reaches an average of 77.8 W m− 2 and a maximum of 187.1 W m− 2. Whereas nocturnal heat output from El Chichón crater lake has an average surface radiative flux of 20.4 W m− 2 and a maximum of 74.3 W m− 2. 相似文献
692.
693.
Graham D. M. Andrews Michael J. Branney Bill Bonnichsen Michael McCurry 《Bulletin of Volcanology》2008,70(3):269-291
The 80 km long NNE-trending Rogerson Graben on the southern margin of the central Snake River Plain, Idaho, USA, hosts a rhyolitic
pyroclastic succession, 200 m thick, that records a period of successive, late-Miocene, large-volume explosive eruptions from
the Yellowstone–Snake River Plain volcanic province, and contemporaneous extension. The succession, here termed the Rogerson
Formation, comprises seven members (defined herein) and records at least eight large explosive eruptions with numerous repose
periods. Five high-grade and extremely high-grade ignimbrites are intercalated with three non-welded ignimbrites and two volcaniclastic
deposits, with numerous repose periods (palaeosols) throughout. Two of the ignimbrites are dominantly rheomorphic and lava-like
but contain subordinate non-welded pyroclastic layers. The ignimbrites are typical Snake River Plain high-silica rhyolites,
with anhydrous crystal assemblages and high inferred magmatic temperatures (≤ 1,025°C). We tentatively infer that the Jackpot
and Rabbit Springs Members may have been emplaced from the Bruneau–Jarbidge eruptive centre on the basis of: (1) flow lineation
trends, (2) crystal assemblage, and (3) radiometric age. We infer that the overlying Brown’s View, Grey’s Landing, and Sand
Springs Members may have been emplaced from the Twin Falls eruptive centre on the basis of: (1) kinematic indicators (from
the east), and (2) crystal assemblage. Furthermore, we have established the contemporaneous evolution of the Rogerson Graben
from the emplacement of the Jackpot Member onwards, and infer that it is similar to younger half-graben along the southern
margin of the Snake River Plain, formed by local reactivation of Basin and Range structures by the northeastwardly migration
of the Yellowstone hot-spot.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
694.
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697.
本文利用一个全球谱模式(T63L9)和1994年4个时段个例的全球客观分析资料探讨了中期数值天气预报的误差订正方法。个例分析的结果表明,采用定常误差订正和时空平滑误差订正方法,误差订正效果显著,可考虑在业务系统中采用。 相似文献
698.
为了研究过极区的短波长电路的衰落特性,在南极长城站收测莫斯科、依尔库茨克的短波授时台信号,并给出各频率对应的衰落深度、衰落率、衰落平均持续时间等参数的统计特征和衰落幅度分布曲线。结果表明:(1)在莫斯科、依尔库茨克-南极长城站两条电路上,其电离层短波信道是快衰落信道,信号幅度衰落绝大部分服从瑞利分布,分布特性与频率、时间、距离、位置关系不大;(2)莫斯科-南极长城站电路的衰落深度与频率、时间有关,频率低,其衰落深度大。但依尔库茨克-南极长城站电路的衰落深度与频率、时间无关,说明衰落深度与频率、时间的关系还要受距离、位置等因素的影响。(3)频率越高,衰落率也越高,04:00~09:00时段内衰落率高于其他时段。 相似文献
699.
张德宇 《海洋通报(英文版)》2004,6(2):28-33
Based on the equilibrium tide theory of the seawater, a model of longperiod variations in air pressure with the lunar motion is derived to advance the climatic tide concept and formulate the climatic tide formula, which provides useful leads for predicting the heavy meteorological catastrophe in Shandong area, even in China. as well as in the whole world. 相似文献
700.