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141.
Passive Seismic Experiment “13 BB Star” in the Margin of the East European Craton,Northern Poland 总被引:1,自引:0,他引:1
Marek Grad Marcin Polkowski Monika Wilde-Piorko Jerzy Suchcicki Tadeusz Arant 《Acta Geophysica》2015,63(2):352-373
The lithosphere-asthenosphere boundary (LAB) is investigated recently very effectively, mostly using seismic methods because of their deep penetration and relatively good resolution. The nature of LAB is still debated, particularly under “cold” Precambrian shields and platforms. Passive experiment “13 BB star” is dedicated to study deep structure of the Earth’s interior in the marginal zone of the East European craton in northern Poland. The seismic network consists of 13 broadband stations on the area of ca. 120 km in diameter. The network is located in the area of well-known sedimentary cover and crustal structure. Good records obtained till now, and expected during next 1-year long recording campaign, should yield images of detailed structure of the LAB, ?410”, “?520”, and ?660” km discontinuities, as well as mantle-core boundary and inner core. 相似文献
142.
通过硫同位素低温平衡系统,分析平衡条件下δ~(34)S_(H_2S)与δ34S热液偏差,获得成矿流体的含硫组分以H_2S为主。成矿阶段δ~(34_S值变化范围狭窄,呈塔式分布,具有岩浆硫特征,柿竹园矿床矿石中的硫来自岩浆流体,即千里山花岗岩。硫同位素fO_2—pH值关系图,投影得出350℃时,fO_2为-28.3~-31.5;250℃时,fO_2为-35.4~-37.5。 相似文献
143.
Monika Bischoff Alpan Cete Ralf Fritschen Thomas Meier 《Pure and Applied Geophysics》2010,167(1-2):63-75
Over the last 25 years mining-induced seismicity in the Ruhr area has continuously been monitored by the Ruhr-University Bochum. About 1,000 seismic events with local magnitudes between 0.7 ≤ M L ≤ 3.3 are located every year. For example, 1,336 events were located in 2006. General characteristics of induced seismicity in the entire Ruhr area are spatial and temporal correlation with mining activity and a nearly constant energy release per unit time. This suggests that induced stresses are released rapidly by many small events. The magnitude–frequency distribution follows a Gutenberg–Richter relation which is a result from combining distributions of single longwalls that themselves show large variability. A high b-value of about 2 was found indicating a lack of large magnitude events. Local analyses of single longwalls indicate that various factors such as local geology and mine layout lead to significant differences in seismicity. Stress redistribution acts very locally since differences on a small scale of some hundreds of meters are observed. A regional relation between seismic moment M 0 and local magnitude M L was derived. The magnitude–frequency distribution of a single longwall in Hamm was studied in detail and shows a maximum at M L = 1.4 corresponding to an estimated characteristic source area of about 2,200 m2. Sandstone layers in the hanging or foot wall of the active longwall might fail in these characteristic events. Source mechanisms can mostly be explained by shear failure of two different types above and below the longwall. Fault plane solutions of typical events are consistent with steeply dipping fracture planes parallel to the longwall face and nearly vertical dislocation in direction towards the goaf. We also derive an empirical relation for the decay of ground velocity with epicenter distance and compare maximum observed ground velocity to local magnitude. This is of considerable public interest because about 30 events larger than M L ≥ 1.2 are felt each month by people living in the mining regions. Our relations, for example, indicate that an event in Hamm with a peak ground velocity of 6 mm/s which corresponds to a local magnitude M L between 1.7 and 2.3 is likely to be felt within about 2.3 km radius from the event. 相似文献
144.
We cloned and sequenced a prtV-like gene from Vibrio anguillarum M3 strain. This prtV gene encodes a putative protein of 918 amino acids, and is highly homologous to the V. cholerae prtV gene. We found that a prtV insertion mutant strain displayed lower gelatinase activity on gelatin agar, lower protease activity against azocasein, and
lower activity for four glycosidases. This prtV mutant strain also had increased activity for two esterases in its extracellular products, as analyzed by the API ZYM system.
In addition, the prtV mutant strain exhibited decreased growth in turbot intestinal mucus and reduced hemolytic activity on turbot erythrocytes.
Infection experiments showed that the LD50 of the prtV mutant strain increased by at least 1 log compared to the wild-type in turbot fish. We propose that prtV plays an important role in the pathogenesis of V. anguillarum. 相似文献
145.
土地覆盖对岩溶地下河碳汇的影响——以广西打狗河流域为例 总被引:6,自引:3,他引:3
以广西打狗河为例,对比分析河流东、西两岸地下河的土地覆盖差异及其对岩溶碳汇的影响。打狗河东岸林地占56.13%,耕地占15.15%;而西岸林地、耕地分别只占20.8%、12.95%。但西岸的裸岩和荒地比例大,分别占29.57%和25.95%,而东岸分别占14.19%和10.98%。植被和土壤覆盖差异导致了东、西两岸碳循环的地球化学指标有明显的差异,东岸地下河水的HCO3-、Ca2+、PCO2(平均分别是233.71mg/L、85.5mg/L、909.46Pa)明显高于西岸(分别为177.26mg/L、64.65mg/L、257.37Pa),而东岸的SIC、pH值(分别为0.12和7.40)又低于西岸(分别是0.38和7.85)。因此,东岸有更强的岩溶动力条件,东岸地下河的平均碳汇强度比西岸高14%,其中,东岸下桥地下河的碳汇强度是西岸旦峒地下河的3.7倍。东西岸地下河水的δ13CDIC、TOC资料也进一步证明了土地覆盖条件对地下河岩溶碳汇具有重要的影响。 相似文献
146.
Lagrangian analysis by clustering 总被引:1,自引:1,他引:0
We propose a new method for obtaining average velocities and eddy diffusivities from Lagrangian data. Rather than grouping
the drifter-derived velocities in geographical bins, we group them by nearest-neighbor distance using a clustering algorithm.
This yields sets with approximately the same number of observations, covering unequal areas. A major advantage is that, because
the number of observations is the same for the clusters, the statistical accuracy is more uniform than with geographical bins.
We illustrate the technique using synthetic data from a stochastic model, employing a realistic mean flow. The latter represents
the surface currents in the Nordic Seas and is strongly inhomogeneous in space. We use the clustering algorithm to extract
the mean velocities and diffusivities and compare the results with the corresponding quantities from the stochastic model.
We perform a similar comparison with the means and diffusivities obtained with geographical bins. Clustering is more successful
at capturing the mean flow and improves convergence in the eddy diffusivity estimates. We discuss both the advantages and
shortcomings of the new method. 相似文献
147.
Xiao Fu Jia-Fu Zhang Duo-Wen Mo Chen-Xi Shi Hui Liu Yi-Yin Li Li-Ping Zhou 《Quaternary Geochronology》2010,5(2-3):353-359
The Qujialing site is a representative Neolithic archaeological site in the middle reaches of the Yangtze River, China. Absence of suitable material for radiocarbon dating in this region makes the timing of the similar sites difficult. Here we applied optically stimulated luminescence (OSL–SAR) and thermoluminescence (TL–SAR) techniques to date the archaeological and natural deposits from the Qujialing site with known age, testing the techniques on samples at archaeological sites in this region. The results showed that the luminescence properties of quartz from sediment and baked earth samples are very similar. The quartz OSL ages obtained for a sediment sample and a baked earth sample from the cultural layer are 5.4 ± 0.3 and 5.1 ± 0.3 ka, respectively. The quartz TL age of the baked earth sample is 5.6 ± 0.5 ka. These dates are consistent with the calibrated radiocarbon ages (4.9 ± 0.1 and 5.1 ± 0.1 ka cal BP (±1σ)) of the two charcoal samples from the cultural layer at a nearby locality, and are also in agreement with the age of Qujialing culture period. The results indicate that the OSL dating techniques can be applied to date similar archaeological sites in the middle reaches of the Yangtze River, China. 相似文献
148.
Hartmut H. Hellmer Monika Rhein Günther Heinemann Janna Abalichin Wafa Abouchami Oliver Baars Ulrich Cubasch Klaus Dethloff Lars Ebner Eberhard Fahrbach Martin Frank Gereon Gollan Richard J. Greatbatch Jens Grieger Vladimir M. Gryanik Micha Gryschka Judith Hauck Mario Hoppema Oliver Huhn Torsten Kanzow Boris P. Koch Gert König-Langlo Ulrike Langematz Gregor C. Leckebusch Christof Lüpkes Stephan Paul Annette Rinke Bjoern Rost Michiel Rutgers van der Loeff Michael Schröder Gunther Seckmeyer Torben Stichel Volker Strass Ralph Timmermann Scarlett Trimborn Uwe Ulbrich Celia Venchiarutti Ulrike Wacker Sascha Willmes Dieter Wolf-Gladrow 《Ocean Dynamics》2016,66(11):1379-1413
149.
根据双城市水文地质条件建立了概念模型,应用GMS软件建立了研究区地质结构模型及地下水数值模拟模型。考虑自然条件以及开采量的影响,设计6种方案对研究区地下水流进行预报,结果显示以设计开采量对水源地进行开采,水源地投产10年后最大中心水位降深不会超过最大允许降深。 相似文献
150.