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941.
国外雨滴谱分布函数的数值试验结果 总被引:4,自引:2,他引:4
采用文献[1]方法,对国外温带地区(北威尔士)^[2]、亚热带地区(瓜得罗普岛)^[3]和热带海洋(GATE-1977)^[4]雨滴谱分布进行了数值试验,结果表明:伽玛分布(n(D)=a.D^ae^-λD)能很好地拟合这些实测雨滴谱,特别是非单调下降谱用伽玛分布拟合明显优于M-P分布拟合,M-P分布仅是伽玛分布的一个特例(α=0)。 相似文献
942.
滇西哀牢山变质杂岩中含石墨岩石的变形-变质温度、构造特征及流变弱化意义 总被引:1,自引:0,他引:1
前人研究表明石墨化作用与变质温度具有良好的相关性,同时室内摩擦实验研究认为少量石墨就能够有效地降低断层摩擦阻力,进而被认为对断层弱化起着重要的固体润滑作用而开始受到大家的关注。但是由于技术手段的限制,我们对天然断裂带中含石墨岩石的宏观-微观构造、变形机制、变形-变质环境以及对岩石流变行为的贡献仍然还不是很清楚。本文在详细的野外地质观测的基础上结合室内实验分析,对新生代红河-哀牢山走滑断裂带内哀牢山深变质杂岩东南侧边界发育的含石墨岩石开展了深入的研究。其中主要侧重利用光学显微镜(OM)、扫描电镜(SEM)、电子背散射衍射(EBSD)以及拉曼光谱(Raman Spectra)技术方法和手段,对宏观及显微构造变形行为、石墨拉曼温度、矿物晶格优选定向(LPO)以及其变形-变质环境进行了综合分析。结果表明,含石墨岩石显微构造特征表现为典型的塑性到超塑性流动构造特征,通过石墨拉曼光谱地质温度计,获得了哀牢山杂岩东部边界与上盘未变质岩石接触的含石墨岩石变形-变质的石墨拉曼温度为462~505℃;而靠近深变质岩含石墨岩石的石墨拉曼温度在511~529℃。基质中强烈细粒化的石墨、石英及长石具有明显的晶格... 相似文献
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944.
The authors proposed a method for obtaining high-quality acceleration seismograms from velocity type seismograms of digital Seismographic network, and took as an example the analysis and processing of the seismograms of a same earthquake that was simultaneously recorded by velocity seismograph CTS1-EDAS24 and strong motion seismograph EST-Q4128 installed in Jixian Station, Tianjin. The calculation steps and the processing method have been discussed in detail. From the analysis and the comparison of the obtained results, it is concluded that the proposed method is simple and effective, and it broadens the application of digital seismographic network. 相似文献
945.
利用多谱勒谱参数检测破碎海浪,提出了一种基于稳态海浪谱模型的判决门限获取方法。利用判决门限获知多谱勒谱对应的海浪是否发生破碎,从而得到海洋中破碎发生的时间和位置。实测数据表明,检测结果与传统碎波统计方法建立的破碎库高度一致。将检测结果应用于海浪参数提取算法,对破碎发生位置提取的海浪参数进行算法修正后,得到的有效浪高和平均海浪周期的误差明显下降,进一步验证了此检测算法的可靠性。 相似文献
946.
The occurrence of pyrochlorophyll a and pyrophaeophytins a and b in the bottom sediments of a small eutrophic lake (Priest Pot, Cumbria, U.K.) is reported on the basis of HPLC coinjection with standards. Assignment of pyrophaeophytins a and b was confirmed by FAB mass spectrometric and nuclear magnetic resonance studies of the isolated components and comparison with standards. The co-occurrence of pyrochlorins with their non-pyro counterparts, even in a surface sediment, shows that decarbomethoxylation can occur at the very earliest stages of the Treibs diagenetic pathway linking the chlorophylls and sedimentary porphyrins. 相似文献
947.
948.
949.
Source parameters and scaling relationships in the Friuli-Venezia Giulia (Northeastern Italy) region
Gianlorenzo Franceschina Stefano Kravanja 《Physics of the Earth and Planetary Interiors》2006,154(2):148-167
We estimated the source parameters of 53 local earthquakes (2.0<ML<5.7) of the Friuli-Venezia Giulia (Northeastern Italy) area, recorded by the short-period local seismic network of the Istituto Nazionale di Oceanografia e Geofisica Sperimentale (OGS), in the period 1995-2003. Data were selected on the basis of high quality locations and focal mechanisms. Standard H/V spectral ratios (HVRS) of the three-component stations of the network were performed in order to assess local amplifications, and only stations showing HVRS not exceeding two were considered for the source parameters estimation. Both velocity and acceleration data were used to compute the SH-wave spectra. Observed spectra were corrected for attenuation effects using an independent regional estimate of the quality factor Q and a station dependent estimate of the spectral decay parameter k. Only earthquakes with ML>3.0 recorded with a sampling rate of 125 cps were used to compute k, thus allowing to visualize a linear trend of the high frequency acceleration spectrum up to 40-50 Hz. SH-wave spectra, corrected for attenuation, showed an ω−2 shape allowing a good fit with the Brune model. Seismic moments and Brune radii ranged between 1.5×1012 and 1.1×1017 N m and between 0.1 and 2.7 km respectively. We obtained Mo=1.1×1017 N m for the seismic moment of the Kobarid (SLO) main shock, in good agreement with the Harvard CMT solution (Mo=3.5×1017 N m). Brune stress drops were confined to the range from 0.07 to 5.31 MPa, with an average value of 0.73 MPa and seem to be approximately constant over five orders of magnitude of seismic moment. Radiated seismic energy computed from two nearby stations scales with seismic moment according to , and apparent stress values are between 0.02 and 4.26 MPa. The observed scatter of Brune stress drop data allowed to hypothesize a scaling relation between seismic moment and corner frequency in order to accommodate both Brune stress drop and apparent stress scalings. No systematic differences are evidenced between stress parameters of earthquakes with different focal mechanisms. As a consequence, a relation of the seismic stress release with the strength of rocks can be hypothesized. A high correlation (r>0.9) of Brune stress drop is found with both apparent stress and RMS stress drop, according to and respectively. 相似文献
950.