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81.
82.
Influence of the Po River runoff on the bacterioplankton community along trophic and salinity gradients in the Northern Adriatic Sea 下载免费PDF全文
Ilaria Pizzetti Giuliano Lupini Fabrizio Bernardi Aubry Francesco Acri Bernhard M. Fuchs Stefano Fazi 《Marine Ecology》2016,37(6):1386-1397
The Po River runoff strongly affects the oceanographic and ecological characteristics of the Northern Adriatic Sea. Catalysed reported deposition ‐ fluorescence in situ hybridization (CARD‐FISH) analysis was employed to assess how the composition of the coastal bacterioplankton community is influenced by the river runoff in two different seasons (spring and autumn). Samples were collected from the water column along a coastal–offshore transect in the Northern Adriatic Sea at different depths. Four clone libraries were then constructed from coastal (0 m) and offshore waters (?65 m). Higher abundances of bacteria were recorded in coastal waters as compared with the offshore samples. This result was mainly due to the trophic state of the water column, and it was related to salinity. Particularly, Actinobacteria and Gammaproteobacteria were affected by the riverine inputs, whereas Bacteroidetes and Alphaproteobacteria showed only minor responses. This was particularly clear in the autumn sample, in which a clear difference between the coastal and the offshore samples was found due to a strong influence of the less saline river water with high nutrient concentrations. Analysis of 205 partial length 16S rRNA gene sequences indicated a high diversity with the dominance of Alphaproteobacteria, Bacteroidetes and Gammaproteobacteria mainly affiliated to coastal and marine bacterioplankton clades. Actinobacteria were also detected and, together with Gammaproteobacteria, strongly follow the freshwater intrusion. Overall, our results indicate that the seasonal difference in the Po River discharge greatly affects the bacterioplankton community. In spring we observed a smooth transition from coastal to open‐sea conditions owing to the more superficial freshwater plume. In autumn the deeper freshwater intrusion in the coastal site and thermal stratification offshore resulted in a marked difference between the coastal and offshore microbial communities. 相似文献
83.
The study investigates the capability of coarse resolution synthetic aperture radar (SAR) imagery to support flood inundation models. A hydraulic model of a 98‐km reach of the River Po (Northern Italy) was calibrated on the October 2000 high‐magnitude flood event with extensive and high‐quality field data. During the June 2008, low‐magnitude flood event a SAR image was acquired and processed in near real time (NRT) in order to provide adequate data for quick verification and recalibration of the hydraulic model. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
84.
A new revised earthquake catalogue for Eastern Algeria [22°N-38°N–4°E-9.5°E], from 419 to 2008, has been compiled as a starting
point for a catalogue dealing with the whole country. The re-evaluation is based on a critical method, and formal criteria
are adopted in the parameterization of the earthquake catalogue. Two digital versions are produced: (a) a basic version, presented
here, including all the compiled data, the authors of each quoted parameter and the quality rank of the macroseismic information;
(b) a second version, obtained after removing doubtful events and parameters, is produced in order to carry out statistical
analyses. The newly compiled earthquake catalogue provides a more reliable picture of the seismicity in Eastern Algeria than
the previous ones as shown by the comparison of the recent catalogues over the common territory and time span. This catalogue
can be easily updated and adapted to the needs of the user. 相似文献
85.
A fairly detailed structural model of the lithosphere-asthenosphere system (thickness, S- and P-wave velocities of the crust
and of the uppermost mantle layers) has been defined in the Calabrian Arc region (Southern Tyrrhenian Sea, Calabria and the
northwestern part of the Ionian Sea) in Southern Italy using seismic data from literature as a priori constraints of the nonlinear
inversion of surface-wave data.
The main features identified by this study are: (1) A very shallow (less then 10 km deep) crust-mantle transition in the Southern
Tyrrhenian Sea and a very low vs just below a very thin lid, in correspondence of the submarine volcanic bodies Magnaghi, Marsili and Vavilov, while the vs in the lid is quite high in the area that separates Marsili from Magnaghi-Vavilov; (2) a shallow and very low vs layer in the uppermost mantle in the areas of the Aeolian Islands, Vesuvius, Phlegraean Fields and Ischia, which represents
their shallow-mantle magma source; (3) a thickened continental crust and lithospheric doubling in Calabria; (4) a crust about
25-km thick and a mantle velocity profile versus depth consistent with the presence of a continental rifted lithosphere, now
thermally relaxed, in the investigated part of the Ionian Sea; (5) the subduction towards northwest of the Ionian lithosphere
below the Southern Tyrrhenian Sea; (6) the subduction of the Adriatic/Ionian lithosphere underneath the Vesuvius and Phlegraean
Fields. 相似文献
86.
87.
Linear Amplification of Horizontal Strong Ground Motion in Zagreb (Croatia) for a Realistic Range of Scaled Point Sources 总被引:2,自引:0,他引:2
Marijan Herak Ivan Lokmer Franco Vaccari Giuliano F. Panza 《Pure and Applied Geophysics》2004,161(5-6):1021-1040
— The linear amplification of the larger horizontal component of strong ground motion along a selected profile in the city of Zagreb is estimated by examining the synthetic waveforms corresponding to a suite of 16 realistically chosen scaled point sources. The accelerograms, computed for the average bedrock model by modal summation, are propagated through local laterally heterogeneous anelastic models by the finite-difference algorithm. The ratio of peak ground acceleration (PGA) and of the response spectra (RS), obtained by using local and bedrock models, define the PGA and RS amplification AMP(PGA) and AMP(RS), respectively. Even variations of the order of commonly observed uncertainties of only dip and rake angles of the causative fault show that both AMP(PGA) and AMP(RS) vary at some sites by more than a factor of two. It follows that, especially for strongly laterally heterogeneous structures, local effects must be determined for each of the relevant sources considering all associated uncertainties as completely as possible. Such a conclusion certainly holds for the case of the microzonation of Zagreb, where the local geology is quite complex, and the seismicity is not confined to a single seismic source zone. 相似文献
88.
ABSTRACTThe scientific literature has focused on uncertainty as randomness, while limited credit has been given to what we call here the “seventh facet of uncertainty”, i.e. lack of knowledge. This paper identifies three types of lack of understanding: (i) known unknowns, which are things we know we don’t know; (ii) unknown unknowns, which are things we don’t know we don’t know; and (iii) wrong assumptions, things we think we know, but we actually don’t know. Here we discuss each of these with reference to the study of the dynamics of human–water systems, which is one of the main topics of Panta Rhei, the current scientific decade of the International Association of Hydrological Sciences (IAHS), focusing on changes in hydrology and society. In the paper, we argue that interdisciplinary studies of socio-hydrological dynamics leading to a better understanding of human–water interactions can help in coping with wrong assumptions and known unknowns. Also, being aware of the existence of unknown unknowns, and their potential capability to generate surprises or black swans, suggests the need to complement top-down approaches, based on quantitative predictions of water-related hazards, with bottom-up approaches, based on societal vulnerabilities and possibilities of failure.
Editor D. Koutsoyiannis; Associate editor S. Weijs 相似文献
89.
Probability-weighted hazard maps for comparing different flood risk management strategies: a case study 总被引:5,自引:1,他引:4
Giuliano Di Baldassarre Attilio Castellarin Alberto Montanari Armando Brath 《Natural Hazards》2009,50(3):479-496
The study proposes an original methodology for producing probability-weighted hazard maps based on an ensemble of numerical
simulations. These maps enable one to compare different strategies for flood risk management. The methodology was applied
over a 270-km2 flood-prone area close to the left levee system of a 28-km reach of the river Reno (Northern Central Italy). This reach is
characterised by the presence of a weir that allows controlled flooding of a large flood-prone area during major events. The
proposed probability-weighted hazard maps can be used to evaluate how a structural measure such as the mentioned weir alters
the spatial variability of flood hazard in the study area. This article shows an application by constructing two different
flood hazard maps: a first one which neglects the presence of the weir using a regular levee system instead, and a second
one that reflects the actual geometry with the weir. Flood hazard maps were generated by combining the results of several
inundation scenarios, simulated by coupling 1D- and 2D-hydrodynamic models. 相似文献
90.
The paper presents the main characteristics of an innovative platform which has been conceived and designed to extend the
operational capabilities of current unmanned surface vehicles in terms of platform stability in waves and of powering requirement
at a relatively high speed. The main idea which rules the project is the realization of a small autonomous surface unit (about
6 m in length) capable of undertaking several tasks in the marine environment even with moderate rough sea conditions. The
designed vessel has the ability to locate, recover, and launch other members of the autonomous fleet (like AUVs or other underwater
devices) and at the same time could carry out a surveillance service of the surrounding areas. To manage these tasks, the
vehicle is designed to provide a fairly good autonomy which is needed to face intermediate-range missions (100 nautical miles).
The choice of a small waterplane area twin hull (SWATH) form has been motivated by its excellent properties of seakeeping
qualities, combined with a non-conventional low resistance underwater hull shape, currently under patenting process, which
is able to reduce to a minimum the resistance of the vessel especially at higher speeds. To obtain the most efficient profile
of the underwater bodies, a systematic optimization with an automatic procedure based on a parametric definition of the geometry,
a state-of-the-art computational fluid dynamics (CFD) flow solver, and a differential evolution global minimization algorithm
have been created and used. As expected, all the final CFD computations on the best design have demonstrated the superior
efficiency of the developed unconventional SWATH technology with respect to different alternatives of current hull typologies. 相似文献