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301.
This computer note describes a method for creating trilinear plots in Microsoft Excel. Macros have been created in MS Excel's internal language: Visual Basic for Applications (VBA). A simple form has been set up to allow the user to input data from an Excel worksheet. The VBA macro is used to convert the triangular data (which consist of three columns of percentage data) into X-Y data. The macro then generates the axes, labels, and grid for the trilinear plot. The X-Y data are plotted as scatter data in Excel. By providing this macro in Excel, users can create trilinear plots in a quick, inexpensive manner. 相似文献
302.
Percolation-theory and fuzzy rule-based probability estimation of fault leakage at geologic carbon sequestration sites 总被引:1,自引:0,他引:1
Yingqi Zhang Curtis M. Oldenburg Stefan Finsterle 《Environmental Earth Sciences》2010,59(7):1447-1459
Leakage of CO2 and displaced brine from geologic carbon sequestration (GCS) sites into potable groundwater or to the near-surface environment
is a primary concern for safety and effectiveness of GCS. The focus of this study is on the estimation of the probability
of CO2 leakage along conduits such as faults and fractures. This probability is controlled by (1) the probability that the CO2 plume encounters a conductive fault that could serve as a conduit for CO2 to leak through the sealing formation, and (2) the probability that the conductive fault(s) intersected by the CO2 plume are connected to other conductive faults in such a way that a connected flow path is formed to allow CO2 to leak to environmental resources that may be impacted by leakage. This work is designed to fit into the certification framework
for geological CO2 storage, which represents vulnerable resources such as potable groundwater, health and safety, and the near-surface environment
as discrete “compartments.” The method we propose for calculating the probability of the network of conduits intersecting
the CO2 plume and one or more compartments includes four steps: (1) assuming that a random network of conduits follows a power-law
distribution, a critical conduit density is calculated based on percolation theory; for densities sufficiently smaller than
this critical density, the leakage probability is zero; (2) for systems with a conduit density around or above the critical
density, we perform a Monte Carlo simulation, generating realizations of conduit networks to determine the leakage probability
of the CO2 plume (P
leak) for different conduit length distributions, densities and CO2 plume sizes; (3) from the results of Step 2, we construct fuzzy rules to relate P
leak to system characteristics such as system size, CO2 plume size, and parameters describing conduit length distribution and uncertainty; (4) finally, we determine the CO2 leakage probability for a given system using fuzzy rules. The method can be extended to apply to brine leakage risk by using
the size of the pressure perturbation above some cut-off value as the effective plume size. The proposed method provides a
quick way of estimating the probability of CO2 or brine leaking into a compartment for evaluation of GCS leakage risk. In addition, the proposed method incorporates the
uncertainty in the system parameters and provides the uncertainty range of the estimated probability. 相似文献
303.
Measurements are reported from two side-looking Doppler systems, which were used to study the discharge front located off the mouth of Chesapeake Bay. One system was a commercial 300-kHz narrow-band acoustic Doppler current profiler (ADCP), which was mounted at a depth of 0.6 m on the port side of a research ship. The other was a prototype X-band, vertically polarized, Doppler radar mounted at a height of about 4 m on the starboard side. Both velocity and backscatter intensity were measured along two beams to ranges of 120 m (ADCP) and 200 m (radar), so that by sailing alternately on each side of the front it was possible to make nearly simultaneous across-front measurements with both systems. Despite the differences in acoustic and radar scattering mechanisms, a combined backscatter intensity surface map could be made showing a continuous frontal signature about 10-m wide and 20 dB above background levels. Each system was also able to measure the same large-scale velocity change across the front, which was dominated by the discharging buoyant bay water flowing at about 50 cm/s relative to the ambient continental shelf water. However, within a 60-m wide zone, the radar system measured velocities up to 75 cm/s larger than the ADCP. Such large velocity differences arose from the radar's sensitivity to motions associated with waves reflecting from the region of strongest across-front current convergence. This frontal convergence was resolved only by the ADCP, which showed a horizontal current change of about 25 cm/s over 10 m and appeared to extend over the upper 2 m or so of the water column. These results show that the combined information from the acoustic and radar systems provide a more complete picture of the frontal currents and wave-current interactions than either system could provide alone 相似文献
304.
305.
Yiannis Tsapras Rachel A. Street Keith Horne Alan Penny Fraser Clarke Hans Deeg Francisco Garzon Simon Kemp Maria Rosa Zapatero Osorio Alejandro Oscoz Abad Santiago Madruga Sanchez Carlos Eiroa Alcione Mora Antxon Alberdi rew Cameron John K. Davies Roger Ferlet Carol Grady Allan W. Harris Javier Palacios reas Quirrenbach Heike Rauer Jean Schneider Dolf de Winter Bruno Merin Enrique Solano 《Monthly notices of the Royal Astronomical Society》2001,325(3):1205-1212
In 1998 the EXPORT team monitored microlensing event light curves using a charge-coupled device (CCD) camera on the IAC 0.8-m telescope on Tenerife to evaluate the prospect of using northern telescopes to find microlens anomalies that reveal planets orbiting the lens stars. The high airmass and more limited time available for observations of Galactic bulge sources make a northern site less favourable for microlensing planet searches. However, there are potentially a large number of northern 1-m class telescopes that could devote a few hours per night to monitor ongoing microlensing events. Our IAC observations indicate that accuracies sufficient to detect planets can be achieved despite the higher airmass. 相似文献
306.
307.
308.
Igneous and shock processes affecting chassignite amphibole evaluated using chlorine/water partitioning and hydrogen isotopes 下载免费PDF全文
Paul A. Giesting Susanne P. Schwenzer Justin Filiberto Natalie A. Starkey Ian A. Franchi Allan H. Treiman Andy G. Tindle Monica M. Grady 《Meteoritics & planetary science》2015,50(3):433-460
Amphibole in chassignite melt inclusions provides valuable information about the volatile content of the original interstitial magma, but also shock and postshock processes. We have analyzed amphibole and other phases from NWA 2737 melt inclusions, and we evaluate these data along with published values to constrain the crystallization Cl and H2O content of phases in chassignite melt inclusions and the effects of shock on these amphibole grains. Using a model for the Cl/OH exchange between amphibole and melt, we estimate primary crystallization OH contents of chassignite amphiboles. SIMS analysis shows that amphibole from NWA 2737 currently has 0.15 wt% H2O. It has lost ~0.6 wt% H2O from an initial 0.7–0.8 wt% H2O due to intense shock. Chassigny amphibole had on average 0.3–0.4 wt% H2O and suffered little net loss of H2O due to shock. NWA 2737 amphibole has δD ≈ +3700‰; it absorbed Martian atmosphere‐derived heavy H in the aftermath of shock. Chassigny amphibole, with δD ≤ +1900‰, incorporated less heavy H. Low H2O/Cl ratios are inferred for the primitive chassignite magma, which had significant effects on melting and crystallization. Volatiles released by the degassing of Martian magma were more Cl‐rich than on Earth, resulting in the high Cl content of Martian surface materials. 相似文献
309.
Richard W. Battarbee Gavin L. Simpson Helen Bennion Christopher Curtis 《Journal of Paleolimnology》2011,45(4):489-505
This paper has two aims: (1) to show for the first time how a natural typology can be established using palaeoecological methods;
and (2) to show how it can be used in lake restoration studies with respect to the definition of recovery targets for acidified
lakes. By defining the characteristic reference assemblages for low alkalinity site types rather than for a specific site
it allows success to be measured more broadly, unconstrained by the specific composition of the pre-acidification flora. We
analyse statistically the pre-acidification diatom assemblages of sediment cores from 121 low alkalinity lakes in the UK in
order to assess whether a reference typology for such lakes can be defined on the basis of their diatom floras. We use samples
dating to ~1850 AD to represent pre-acidification conditions. The results show that three main clusters can be identified,
two dominated by benthic taxa (Clusters 1 and 3) and one dominated by planktonic taxa (Cluster 2). Cluster 1 is characterised
by taxa such as Brachysira vitrea, Cymbella microcephala and Fragilaria spp., Cluster 2 by Cyclotella comensis, C. radiosa, Asterionella formosa, Aulacoseira subarctica and Achnanthes minutissima and Cluster 3 by Eunotia incisa, Frustulia rhomboides var. saxonica, Fragilaria virescens var. exigua, and Cymbella perpusilla. Although environmental data for 1850 AD are not available it is apparent from the contemporary distribution of the taxa
in the different clusters that Cluster 2 represents the most alkaline pre-acidification conditions. Some sites in this cluster
have been acidified, but some, especially the larger, deeper lakes have been enriched. Cluster 1 includes sites that contain
diatoms with relatively high pH optima (pH 6.4–7.4) whereas Cluster 3 sites contain diatoms with the lowest pre-acidification
pH conditions in the data-set. Sites in this cluster also have the lowest base cation concentrations at the present day and
include the sites in the UK that have been most affected by acid deposition. 相似文献
310.