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371.
In this paper, based on the previous study of practical use of seismic regime windows and seismic regime belts, the problem
of establishing a “seismic regime network” consisting of “windows” and “belts” is further posed and discussed according to
the observed fact that many “windows” and “belts” make responses to one earthquake. For the convenience of usage, the “seismic
regime network” is divided into two classes, the first class and the second one. The former can be used in tendency prediction
for long-term seismic activity in a large area, the latter used in short-term prediction in a small area. In this paper, after
briefly discussing the physical significance of “seismic regime network”, it is pointed out that this simple and easily used
method can be used to observe and extract seismic precursory information from a large area before a great earthquake, thus
it can provide a reliable basis for the analysis and judgement of seismic regime tendency in time and space. No doult, this
method is of certain practical significance.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 161–169, 1991.
The English version of this paper is improved by Prof. Shaoxie Xu. 相似文献
372.
The mechanisms of finite brittle strain 总被引:1,自引:0,他引:1
373.
374.
通过对柴达木盆地北缘西段重点探井的岩心观测、重矿物分析、测井数据及地震资料的分析,研究了冷湖构造带古近系沉积体系及演化特征和不同时期沉积微相及砂体的展布规律.结果认为,冷湖构造带古近系主要发育冲积扇-辫状河-辫状河三角洲-湖泊沉积体系,物源来自北东方向的小赛什腾山和赛什腾山附近.古近系路乐河组(E1+2)沉积期,主要发育辫状河以及辫状河三角洲平原沉积,仅在靠近山前发育少量冲积扇沉积;至下干柴沟组(E3)沉积时期,主要发育辫状河、辫状河三角洲平原、辫状河三角洲前缘及滨-浅湖沉积.古近纪时期冷湖构造带表现为一次较大规模的水进过程,纵向沉积继承性明显,很好地记录了这一沉积演化过程.这一沉积体系及演化过程有利于粗碎屑和细碎屑交互沉积,形成较好的储盖组合,为柴达木盆地冷湖构造带下一步的油气勘探提供了可靠的地质依据. 相似文献
375.
用王亚光研究大型矿床空间分布规律理论来研究西昌—滇中地区大、中型内生矿床的分布规律及预测,用“矿结”一词来表明经纬线方向深大断裂交汇处是大矿的分布空间。1990年所预测的一些成矿区为1991年地质找矿工作所证实,如大红山式铁铜矿的新发现和会东发嵩铝锌矿的新进展。 相似文献
376.
从闪长质岩石包体角度探讨太行山——燕山造山带壳幔成矿作用 总被引:5,自引:3,他引:5
文中首次从闪长质岩包体的角度讨论了上地幔,中,下地壳成分及岩浆演化过程对成矿作用的影响,指出太行山-燕山造山带成矿作用及其区域成矿规律明显受到壳幔成矿体系的制 相似文献
377.
Suo Shutian 《中国地质大学学报(英文版)》1995,(1)
Crustal Texture and Rheological Evolution ofTongbai-Dabie Orogenic Belt,China¥SuoShutian(FacultyofEarthSciences,ChinaUniversi... 相似文献
378.
A. B. Roy 《Journal of Earth System Science》1995,104(3):349-371
The lead-zinc bearing Proterozoic rocks of Zawar, Rajasthan, show classic development of small-scale structures resulting
from superposed folding and ductile shearing. The most penetrative deformation structure noted in the rocks is a schistosity
(S
1) axial planar to a phase of isoclinal folding (F
1). The lineations which parallel the hinges ofF
1 folds are deformed by a set of folds (F
2) having vertical or very steep axial planes. At many places a crenulation cleavage (S
2) has developed subparallel to the axial planes ofF
2 folds, particularly in the psammopelitic rocks. The plunge and trend ofF
2 folds vary widely over the area.
Deformation ofF
2 folds into hook-shaped geometry and development of another set of axial planar crenulation cleavage are the main imprints
of the third generation folds (F
3) in the region. In addition to these, there are at least two other sets of cleavage planes with corresponding folds in small
scales. More common among these is a set of recumbent and reclined folds (F
4), developed on steeply dipping early-formed planes. Kink bands and associated sharp-hinged folds represent the other set
(F
5).
Two major refolded folds are recognizable in the map pattern of the Zawar mineralised belt. The larger of the two, the Main
Zawar Fold (MZF), shows a broad hook-shaped geometry. The other large-scale structure is the Zawarmala fold, lying south-west
of the MZF. Both the major structures show truncation of lithological units along their respective east ‘limbs’, and extreme
variation in the width of formations. The MZF is primarily the result of superimposition ofF
3 onF
2.F
1 folds are relatively smaller in scale and are recognizable in the quartzite unit which responded to deformation mainly by
buckle shortening. Large-scale pinching-and-swelling that appears in the outcrop pattern seems to be a pre-F2 feature.
The structural evolutionary model worked out to explain the chronology of the deformational features and the large-scale out-crop
pattern envisages extreme east-west shortening following formation ofF
1 structures, resulting in the formation of tight and isoclinal antiforms (F
2) with pinched-in synforms in between. These latter zones evolved into a number of ductile shear zones (DSZs). The east-west
refolding of the large-scaleF
2 isoclinal antiforms seems to be the consequence of a continuous deformation and resultant migration of folds along the DSZs.
The main shear zone which wraps the Zawar folds followed a curved path.
Because of the penetrative nature of theF
2 movement, the early lineations which were at high angles to the later ones (as is evident in the west of Zawarmala), became
subparallel to the trend ofF
2 folding over a large part of the area. Further, the virtually coaxial nature ofF
2 andF
3 folds and the refolding ofF
3 folds by a new set of N-S folds is an indication of continuous progressive deformation. 相似文献
379.
秦岭造山带松树沟元古宙蛇绿岩及其大地构造背景 总被引:2,自引:0,他引:2
秦岭造山带松树沟蛇绿岩大约是在983Ma,构造就位于秦岭杂岩(Pt1)之上的异地构造岩片.由变质橄榄岩、堆积橄榄岩和火山岩系组成。变质橄榄岩以纯橄榄岩为主。堆晶岩分为单斜辉石型和斜方辉石型两类。火山岩由拉斑玄武岩和低铝安山岩组成,εNd(T)为+4.1~+6.4,表现出N、T、P三种稀土分配型式和非正常洋脊玄武岩地球化学的特征。综合分析认为,这个古老蛇绿岩是在一种位于洋中脊之上的洋岛环境中形成的,代表了晋宁期华北板块与扬子板块之间古洋盆的残骸。 相似文献
380.
聚煤盆地富煤规律是煤地质学研究之焦点。富煤规律研究的突出进展主要包括聚煤模式、富煤带和富煤单元以及现代泥炭比较沉积学研究。尤其是近年来富煤单元和现代泥炭比较沉积学研究更清楚地揭示煤赋存规律与成因煤相和工艺煤相之间的内在联系,从而为聚煤盆地优质煤的预测提供有效的方法。 相似文献