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141.
过山气流与大兴安岭焚风 总被引:1,自引:0,他引:1
本文利用二维大气中尺度数值模式,模拟了冬季1月份大兴安岭东坡的焚风现象,并讨论了该焚风的成因。 相似文献
142.
The hydrological response of soil surfaces to rainfall as affected by cover and position of rock fragments in the top layer 总被引:1,自引:0,他引:1
Rainfall experiments have been conducted in the laboratory in order to assess the hydrological response of top soils very susceptible to surface sealing and containing rock fragments in different positions with respect to the soil surface. For a given cover level, rock fragment position in the top soil has an ambivalent effect on water intake and runoff generation. Compared to a bare soil surface rock fragments increase water intake rates as well as time of runoff concentration and decrease runoff volume if they rest on the soil surface. For the same cover level, rock fragments reduce infiltration rate and enhance runoff generation if they are well embedded in the top layer. The effects of rock fragment position on infiltration rate and runoff generation are proportional to cover percentage. Micromorphological analysis and measurements of the saturated hydraulic conductivity of bare top soils and of the top layer underneath rock fragments resting on the soil surface reveal significant differences supporting the mechanism proposed by Poesen (1986): i.e. runoff generated as rock flow or as Horton overland flow can (partly) infiltrate into the unsealed soil surface under the rock fragments, provided that they are not completely embedded in the top layer. Hence, rock fragment position, beside other rock fragment properties, should be taken into account when assessing the hydrological response of soils susceptible to surface sealing and containing rock fragments in their surface layers. A simple model, based on the proportions of bare soil surface, soil surface occupied by embedded rock fragments, and soil surface covered with rock fragments resting on the soil surface, describes the runoff coefficient data relatively well. 相似文献
143.
A swallow-tail type catastrophic model of earthquake process 总被引:1,自引:0,他引:1
(殷有泉)(杜静)Aswallow-tailtypecatastrophicmodelofearthquakeprocess¥You-QuanYINandJingDU(PekingUniversdy,Beijing100871,China)(Nort... 相似文献
144.
本文对煤岩基本力学性质、煤层水压致裂缝形成条件、裂缝形态以及裂缝开裂角方位等基本理论进行了研究与探讨,通过大量煤岩力学性质测试,证实了试验区目的层煤岩弹性模量低,泊松比较高,脆性大,易破碎,易压缩。文章还得出了目的层煤岩Mohr断裂准则二次抛物线型包络线,煤层水压致裂裂缝形式判断,裂缝开裂角方位的计算公式以及有关结论。 相似文献
145.
本文结合厦门海沧经济开发区路网规划工作,着重探讨了区域公路网规划的分区、原则、交通量预测、路网布局、实施方案等问题。 相似文献
146.
147.
I. Becchi E. Caporali L. Castellani E. Palmisano F. Castelli 《Surveys in Geophysics》1995,16(2):227-252
In the study of flash-flood occurrence in small catchments the lack of flow measurements is often one of the main limiting factors. Prior to estimating the forecasting potentialities and techniques for such events, an accurate reconstruction of past event flood dynamics is first required. This issue is here addressed by analyzing, with the use of a distributed hydrological model, the hydrometeorological conditions in which a severe flash-flood occurred, on October 1992, on a 48 square kilometers catchment in the Arno basin. Such an event was caused by the persistence of intense convective clusters on the background of widespread rain bands of frontal origin. The distributed hydrological model here adopted is devoted to simulate the evolution and the variability of the primary processes involved in the runoff cycle. Together with the hydrological model structure, other particular aspects of the event reconstruction procedure are discussed: the managing and processing of the information coming from different sensors, with different temporal and spatial resolutions; the identification of local precipitation dynamics (frontal or convective) within small areas of integrated radar and rain gauges data fields; the interpolation of rain gauge data on the basis of the radar-estimated spatial correlation. The results of the distributed modeling, concerning the estimate of the flood wave at various sites, are compared with analogous results obtained with simpler lumped models. 相似文献
148.
B. H. Briz-Kishore 《Journal of Earth System Science》1982,91(3):219-234
The use of digital models has increased significantly in recent years with the accessibility of fast computing machines. A
variable dimensioned digital model was constructed for the Shadnagar granite basin using SPECTRUM-7 micro computer to integrate
various hydrogeological characteristics and for their quantitative evaluation. The basin has an areal extent of 437 sq km
and is demarcated with clear water divides in all directions. Transmissivity, recharge and discharge at each cell of the basin
area were estimated by trial and error simulation of the hydrogeological phenomenon under steady state condition. Dynamic
simulation at representative nodes facilitated the estimation of storage coefficient. The capability of the constructed model
was established by the conformance of the simulated hydrographs with the actual behaviour of the ground water system. The
entire studies ammended the earlier arrived estimates of various input/output hydrogeological parameters and evolved a methodology
for efficient processing of aquifer simulation data 相似文献
149.
从水流挟沙力和河槽形态规律分析黄河调水调沙 总被引:3,自引:0,他引:3
在分析水流挟沙力和河槽水力形态规律的基础上,研究调节流量、含沙量和泥沙组成的优化组合,解决河道输沙减淤和河槽相对稳定问题,提出调水调沙方向。达到合理利用水资源和河道减淤与治理相结合的目的. 相似文献
150.
国家大剧院深基坑地下水控制设计及施工技术 总被引:3,自引:0,他引:3
国家大剧院基坑地下水控制是大剧院工程的三大难题之一,也是专家们讨论的焦点。经过水文地质试验和充分论证,确定了地下水控制方案和施工方法,即采用反循环成井工艺施工引渗井,将上层滞水和潜水引渗到第一层承压含水层中消纳,保证第一步基坑开挖至-15 7m;在-15 7m位置采用连续墙阻隔第一层承压水,并使用旋挖钻机在槽内施工降水井,疏干槽内承压含水层并进行越流补给控制,保证基坑开挖至-26m;在歌剧院台仓局部加深部份(-32 5m),采用封闭布设减压井,解决基坑开挖和台仓地下结构施工时基坑突涌的问题;最后采用特殊的封井技术,将井管内高于槽底约10m的承压水头封堵在槽底以下0 5m,安全截断井管,保证了基础施工。 相似文献