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701.
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本文收集了笔者近年来在栾川西部地区所作的激电资料,通过综合整理和研究,分析了铝锌矿的直流激电异常特征。探讨了应用直流激电法探寻铅锌矿应注意的若干问题,解决了该区铅锌矿与其它矿种的区分,取得了较好的找矿成果。 相似文献
704.
Gehad M. Saleh 《中国地球化学学报》2006,25(2)
The Zargat Na'am ring complex crops out 90 km NW of Shalatin City in the Southeastern Desert of Egypt. The ring complex forms a prominent ridge standing high above the surrounding mafic-ultramafic hills. It is cut by two sets of joints and faults which strike predominantly NNW-SSE and E-W,and is injected by dikes, porphyritic alkaline syenites, and felsite porphyries. It consists of alkali syenites, alkali quartz syenites, and peralkaline arfvedsonite-bearing granitic and pegmatitic dikes and sills.The complex is characterized locally by extreme enrichments in REEs, wolframite and rare, high field strength metals (HFSM), such as Zr and Nb. The highest concentrations ( 1.5 wt% Zr, 0.25 wt% Nb,0.6 wt% ∑REEs) occur in aegirine-albite aplites that formed around arfvedsonite pegmatites. Quartzhosted melt inclusions in arfvedsonite granite and pegmatite provide unequivocal evidence that the peralkaline compositions and rare metal enrichments are primary magmatic features. Glass inclusions in quartz crystals also have high concentrations of incompatible trace elements including Nb (750 × 10-6), Zr (2500 × 10-6) and REEs (1450 × 10-6). The REEs, Nb and Zr compositions of the aegirine-albite aplites plot along the same linear enrichment trends as the melt inclusions, and Y/Ho ratios mostly display unfractionated, near-chondritic values. The chemical and textural features of the aegirine-albite aplites are apparently resultant from rapid crystallization after volatile loss from a residual peralkaline granitic melt similar in composition to the melt inclusions. 相似文献
705.
Frances J. Hein 《Natural Resources Research》2006,15(2):67-84
As conventional oil and gas reservoirs become depleted other unconventional energy sources have to be recovered and produced.
Four of the major unconventional resources that are strategic for North American interests are heavy oil, oil sands, oil shales,
and coal-bed methane. Recent interest and activity in Canada’s vast oil sands are progressing rapidly as soaring oil prices
are fueling a ‘gold rush’ in oil sands development in Alberta. This interest is evident by the record-number of oil sands
and heavy oil presentations at Energy Minerals Division (EMD)-sponsored sessions at the 2004 and 2005 Annual Conventions of
the American Association of Petroleum Geologists (AAPG), held in Dallas, TX and Calgary, AB. 相似文献
706.
We present new in situ observations of systematic asymmetry in the pattern of damage expressed by fault zone rocks along sections of the San Andreas,
San Jacinto, and Punchbowl faults in southern California. The observed structural asymmetry has consistent manifestations
at a fault core scale of millimeters to meters, a fault zone scale of meters to tens of meters and related geomorphologic
features. The observed asymmetric signals are in agreement with other geological and geophysical observations of structural
asymmetry in a damage zone scale of tens to hundreds of meters. In all of those scales, more damage is found on the side of
the fault with faster seismic velocities at seismogenic depths. The observed correlation between the damage asymmetry and
local seismic velocity structure is compatible with theoretical predictions associated with preferred propagation direction
of earthquake ruptures along faults that separate different crustal blocks. The data are consistent with a preferred northwestward
propagation direction for ruptures on all three faults. If our results are supported by additional observations, asymmetry
of structural properties determined in field studies can be utilized to infer preferred propagation direction of large earthquake
ruptures along a given fault section. The property of a preferred rupture direction can explain anomalous behavior of historic
rupture events, and may have profound implications for many aspects of earthquake physics on large faults. 相似文献
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710.
闽北地质灾害的分布特征及其成因分析 总被引:1,自引:0,他引:1
通过分析闽北地质灾害与降水特征表明:闽北地质灾害时间分布与降水、尤其是与暴雨的分布一致。其空间分布与地质条件的分布一致,而与年降雨量、3~8月降雨量的分布相反。地质灾害发生数的74.9%均在针叶林及经济林中,95.7%发生在坡度>20°的陡坡处。地质灾害与岩土性质以及岩土结构有一定的关系。当浮土厚度在5m或以上时极易发生地质灾害。因此,闽北地质灾害的发生的主要因素是地质条件,强降雨则是其重要的触发条件,人类活动也是诱发地质灾害的因素之一。文章根据地质条件将闽北的地质灾害按易发程度分为:高易发区、中易发区及低易发区。 相似文献