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991.
AbstractRunoff discharge in the Tuku lowlands, Taiwan, has increased with land development. Frequent floods caused by extreme weather conditions have resulted in considerable economic and social losses in recent years. Currently, numerous infrastructures have been built in the lowland areas that are prone to inundation; the measures and solutions for flood mitigation focus mainly on engineering aspects. Public participation in the development of principles for future flood management has helped both stakeholders and engineers. An integrated drainage–inundation model, combining a drainage flow model with a two-dimensional overland-flow inundation model is used to evaluate the flood management approaches with damage loss estimation. The proposed approaches include increasing drainage capacity, using fishponds as retention ponds, constructing pumping stations, and building flood diversion culverts. To assess the effects on the drainage system of projected increase of rainfall due to climate change, for each approach simulations were performed to obtain potential inundation extent and depth in terms of damage losses. The results demonstrate the importance of assessing the impacts of climate change for implementing appropriate flood management approaches.Editor Z.W. KundzewiczCitation Chang, H.-K., Tan, Y.-C., Lai, J.-S., Pan, T.-Y., Liu, T.-M., and Tung, C.-P., 2013. Improvement of a drainage system for flood management with assessment of the potential effects of climate change. Hydrological Sciences Journal, 58 (8), 1581–1597. 相似文献
992.
《水文科学杂志》2013,58(4)
Abstract The global climate change may have serious impacts on the frequency, magnitude, location and duration of hydrological extremes. Changed hydrological extremes will have important implications on the design of future hydraulic structures, flood-plain development, and water resource management. This study assesses the potential impact of a changed climate on the timing and magnitude of hydrological extremes in a densely populated and urbanized river basin in southwestern Ontario, Canada. An ensemble of future climate scenarios is developed using a weather generating algorithm, linked with GCM outputs. These climate scenarios are then transformed into basin runoff by a semi-distributed hydrological model of the study area. The results show that future maximum river flows in the study area will be less extreme and more variable in terms of magnitude, and more irregular in terms of seasonal occurrence, than they are at present. Low flows may become less extreme and variable in terms of magnitude, and more irregular in terms of seasonal occurrence. According to the evaluated scenarios, climate change may have favourable impacts on the distribution of hydrological extremes in the study area. 相似文献
993.
《水文科学杂志》2013,58(1)
Abstract Abstract The exploitation of an alluvial aquifer (2 × 106 m3) has been developed since 1998 in the Valley of Forquilha (Quixeramobim, State of Ceará). For this purpose, 165 wells were drilled along the 23 km of the valley that supplies 500 families and their farms. Monthly monitoring of piezometric and electrical conductivity (2000–2003) show seasonal variations in the water volume (35%) and in the mean value of the conductivity (800–1200 µS cm-1). A conceptual hydrogeological model was developed. Analysis of the data and simulations highlight that the recharge of the aquifer is mainly due to infiltration from the river in the rainy season, which is of the order of 1% of the rain over the catchment area (195 km2). The abstractions increase the recharge between 30 and 60%. The model makes it possible to propose scenarios of sustainable exploitation of the water resource in the catchment. For the period between 1970 and 1988, other simulations show that it would have been possible to maintain irrigated cultures on 75 ha for 80% of the time. During the remaining 20%, the water level is too low, and farmers would have to reduce the irrigated area. 相似文献
994.
995.
Barodesy is a new approach to constitutive modelling of soil. It is based on Goldscheider's principles and maps stretching directions onto corresponding stress directions with the help of a simple exponential function. This mapping also determines a critical state surface in principal stress space. The article investigates this surface and relates it to the well‐known Matsuoka–Nakai failure criterion. It turns out that the difference between these two surfaces is negligible for practical applications. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
996.
In this first part of the work, we develop macroscopic models for migration and diffusion–migration of ionic species in saturated porous media, based on periodic homogenization. The prior application is chloride transport in cementitious materials. The dimensional analysis of Nernst–Planck equation lets appear to dimensionless numbers characterizing the ionic transfer in the porous medium. Using experimental data obtained from electrodiffusion tests on cement‐based materials (Part II), these dimensionless numbers are linked to the perturbation parameter ?. For a strong imposed electrical field, the asymptotic expansion of Nernst–Planck equation leads to a macroscopic model where the migration is predominant. For a weak imposed electrical field or in natural diffusion, we obtain a macroscopic model coupling diffusion and migration at the same order. In both models, the expression of the homogenized diffusion tensor is identical and only involves the geometric properties of the material microstructure. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
997.
O. Bartoli L. Tajčmanová B. Cesare A. Acosta‐Vigil 《Journal of Metamorphic Geology》2013,31(7):775-789
Stromatic metatexites occurring structurally below the contact with the Ronda peridotite (Ojén nappe, Betic Cordillera, S Spain) are characterized by the mineral assemblage Qtz+Pl+Kfs+Bt+Sil+Grt+Ap+Gr+Ilm. Garnet occurs in low modal amount (2–5 vol.%). Very rare muscovite is present as armoured inclusions, indicating prograde exhaustion. Microstructural evidence of melting in the migmatites includes pseudomorphs after melt films and nanogranite and glassy inclusions hosted in garnet cores. The latter microstructure demonstrates that garnet crystallized in the presence of melt. Re‐melted nanogranites and preserved glassy inclusions show leucogranitic compositions. Phase equilibria modelling of the stromatic migmatite in the MnO–Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2–O2–C (MnNCaKFMASHOC) system with graphite‐saturated fluid shows P–T conditions of equilibration of 4.5–5 kbar, 660–700 °C. These results are consistent with the complete experimental re‐melting of nanogranites at 700 °C and indicate that nanogranites represent the anatectic melt generated immediately after entering supersolidus conditions. The P–T estimate for garnet and melt development does not, however, overlap with the low‐temperature tip of the pure melt field in the phase diagram calculated for the composition of preserved glassy inclusions in garnet in the Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O (NCKFMASH) system. A comparison of measured melt compositions formed immediately beyond the solidus with results of phase equilibria modelling points to the systematic underestimation of FeO, MgO and CaO in the calculated melt. These discrepancies are present also when calculated melts are compared with low‐T natural and experimental melts from the literature. Under such conditions, the available melt model does not perform well. Given the presence of melt inclusions in garnet cores and the P–T estimates for their formation, we argue that small amounts (<5 vol.%) of peritectic garnet may grow at low temperatures (≤700 °C), as a result of continuous melting reactions consuming biotite. 相似文献
998.
Allometric relations between fluvial impulse and morphometric parameters of floodplain lakes
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The general role of river water input in shaping the basic morphometric parameters of floodplain lakes has been previously investigated. However, the process has not been quantitatively described in detail. This study is the first attempt in the literature to determine the allometric relation between fluvial impulse, expressed as Fluvial Connectivity Quotient, and morphometric parameters of six floodplain lakes of Bug River valley in the period 1952–2014. This relationship is given by Y = aXb, from which the value of b exponent was analysed to determine the strength of the allometric relation. Extreme values of allometric compounds during the time period under study ranged from 5.99 to ?4.91. Volume was the morphometric parameter showing the highest variability in all the lakes. General similarity in allometric relations was observed in the lakes under study. During analysis, no long‐term trends were observed in the relationship between the Fluvial Connectivity Quotient and morphometric parameters. The results obtained show that fluvial impulse was the factor determining the variability of morphometric parameters of the lakes. Direct catchments topography of lake has periodically (during limnophase periods) played a significant role in shaping the morphometry of floodplain lakes. The most stable allometric relations occurred in a confluent lake, with a low limnological effective rise value and consequently, relatively long potamophase periods.Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
999.
Regional‐scale 40Ar–39Ar data presented in this paper reveal significant across‐strike and along‐strike age differences in the Committee Bay belt (CBb), Rae Province, Nunavut, Canada, that complement variations in observed monazite ages. 40Ar–39Ar hornblende ages are c. 1795, 1775, and 1750 Ma in the western, eastern and central parts of the Prince Albert Group (PAG) domain respectively. The migmatite domain and Walker Lake intrusive complex are characterized by c. 1750–1730 40Ar–39Ar hornblende ages without significant along‐strike variation. The 40Ar–39Ar data provide important constraints on the cooling history and on thermal modelling that elucidates the controls on diachroneity and metamorphic patterns within the belt. In the western CBb, prograde monazite growth occurred 26 ± 10 Myr earlier in the migmatite domain (1864 ± 9 Ma; peak P–T = 5 kbar?700 °C) than in the PAG domain (1838 ± 5 Ma; peak P–T = 5 kbar?580 °C). Calculations indicate that this earlier monazite growth results from tectonic thickening of higher heat productivity Archean lithologies in the migmatite domain, which undergoes more rapid prograde heating than the less radiogenetic and lower grade rocks of the PAG domain. Granite generation via biotite dehydration melting at 800 °C and 20 km depth is predicted to occur c. 1835 Ma, in agreement with geochronological constraints. The tectonic burial of crustal domains with contrasting radiogenic properties also explains the general congruence of lower to upper amphibolite facies metamorphic zones generated during the two main orogenic cycles (i.e. M2–D1 and M3–D2). The modelled timing of prograde monazite growth in the migmatite domain suggests that D2 tectonic thickening began at 1872 ± 9 Ma, some 8 ± 3 Myr before monzazite growth, coeval with the inferred time of collision of the Meta Incognita terrane with the southern Rae Province. Along‐strike diachroneity, reflected in 25 Myr younger monazite and 40Ar–39Ar hornblende ages in the eastern relative to the western PAG domain, cannot be accounted for by heat productivity contrasts along the belt. Instead the younger deformation and metamorphism in the eastern CBb was driven by its proximity to the eastern promontory of the Superior Province which collided with the Rae Province at c. 1820 Ma. The 40Ar–39Ar data presented here support the interpretation that the youngest monazite in the CBb crystallized at c. 1790 Ma in the central CBb when this part of the belt was downfolded into a gentle synformal structure while the western part of the belt cooled through 40Ar–39Ar hornblende closure. The results of this study illustrate the important influence of contrasting rock properties on the thermal evolution of orogenic belts and on the temporal record of this evolution. 相似文献
1000.
The principal challenge in the parameterization of storm flow models for agricultural catchments with an artificial drainage network and fields with different degrees of tillage lies in the parsimonious definition of distributed model parameters in a way that reduces the number of calibration parameters to a justifiable minimum. This paper presents a comprehensive case study for the parameter estimation of a distributed storm flow model applied to an agricultural catchment (0.91 km2) in the Mediterranean region. Model parameterization was combined with procedures for multi‐criteria, multi‐storm calibration, where we automatically calibrated three parameters related to flow velocity and infiltration, and compared single and multi‐storm criteria that are based on discharge volume, peak flow, and the Nash–Sutcliffe coefficient. Multi‐storm calibration yielded a set of parameter values for the simulation batch with best multi‐storm overall performance, which are close to the median values in the pre‐calibration of individual storms. Our results suggest that flow velocities and proportionality of the channel infiltration rate do not vary significantly over the course of 11 years. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献