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251.
Richard A. Esposito Jack C. Pashin Denise J. Hills Peter M. Walsh 《Environmental Earth Sciences》2010,60(2):431-444
CO2 pilot injection studies, with site-specific geologic assessment and engineering reservoir design, can be instrumental for
demonstrating both incremental enhanced oil recovery and permanent geologic storage of greenhouse gases. The purpose of this
paper is to present the geologic and reservoir analyses in support of a field pilot test that will evaluate the technical
and economic feasibility of commercial-scale CO2-enhanced oil recovery to increase oil recovery and extend the productive life of the Citronelle Oil Field, the largest conventional
oil field in Alabama (SE USA). Screening of reservoir depth, oil gravity, reservoir pressure, reservoir temperature, and oil
composition indicates that the Cretaceous-age Donovan sand, which has produced more than 169 × 106 bbl in Citronelle Oil Field, is amenable to miscible CO2 flooding. The project team has selected an 81 ha (200 ac) 5-spot test site with one central gas injector, two producers,
and two initially temporarily abandoned production wells that are now in production. Injection is planned in two separate
phases, each consisting of 6,804 t (7,500 short tons) of food-grade CO2. The Citronelle Unit B-19-10 #2 well (Permit No. 3232) is the CO2 injector for the first injection test. The 14-1 and 16-2 sands of the upper Donovan are the target zones. These sandstone
units consist of fine to medium-grained sandstone that is enveloped by variegated mudstone. Both of these sandstone units
were selected based on the distribution of perforated zones in the test pattern, production history, and the ability to correlate
individual sandstone units in geophysical well logs. The pilot injections will evaluate the applicability of tertiary oil
recovery to Citronelle Field and will provide a large volume of information on the pressure response of the reservoirs, the
mobility of fluids, time to breakthrough, and CO2 sweep efficiency. The results of the pilot injections will aid in the formulation of commercial-scale reservoir management
strategies that can be applied to Citronelle Field and other geologically heterogeneous oil fields and the design of similar
pilot injection projects. 相似文献
252.
Five main belt asteroids, 2 Pallas, 129 Antigone, 409 Aspasia, 532 Herculina, and 704 Interamnia were imaged with the adaptive optics system on the 10 m Keck-II telescope in the near infrared on one night, August 16, 2006. The three axis dimensions and rotational poles were determined for Pallas, Antigone, Aspasia, and Interamnia, from their changing apparent sizes and shapes as measured with parametric blind deconvolution. The rotational pole found for Interamnia is much different from all previous work, including our own at Lick Observatory the previous month. Although images of Herculina were obtained at only two rotational phases, its rotation appears to be opposite to that predicted from the lightcurve inversion model of M. Kaasalainen, J. Torppa, and J. Piironen [2002. Icarus 159, 369-395]. A search for satellites was made in all of the asteroid images, with negative results, but three trailing stars around Herculina (200 km diameter), down to 8.9 magnitudes fainter and between 1 and 115 asteroid radii (100 to 11,500 km) from the asteroid, establishes an upper limit of 3.3 km for any object with the same albedo near Herculina. 相似文献
253.
Ralf Srama Thomas Stephan Eberhard Grün Norbert Pailer Anton Kearsley Amara Graps Rene Laufer Pascale Ehrenfreund Nicolas Altobelli Kathrin Altwegg Siegfried Auer Jack Baggaley Mark J. Burchell James Carpenter Luigi Colangeli Francesca Esposito Simon F. Green Hartmut Henkel Mihaly Horanyi Annette Jäckel Sascha Kempf Neil McBride Georg Moragas-Klostermeyer Harald Krüger Pasquale Palumbo Andre Srowig Mario Trieloff Peter Tsou Zoltan Sternovsky Oliver Zeile Hans-Peter Röser 《Experimental Astronomy》2009,23(1):303-328
The scientific community has expressed strong interest to re-fly Stardust-like missions with improved instrumentation. We
propose a new mission concept, SARIM, that collects interstellar and interplanetary dust particles and returns them to Earth.
SARIM is optimised for the collection and discrimination of interstellar dust grains. Improved active dust collectors on-board
allow us to perform in-situ determination of individual dust impacts and their impact location. This will provide important
constraints for subsequent laboratory analysis.
The SARIM spacecraft will be placed at the L2 libration point of the Sun–Earth system, outside the Earth’s debris belts and
inside the solar-wind charging environment. SARIM is three-axes stabilised and collects interstellar grains between July and
October when the relative encounter speeds with interstellar dust grains are lowest (4 to 20 km/s). During a 3-year dust collection
period several hundred interstellar and several thousand interplanetary grains will be collected by a total sensitive area
of 1 m2. At the end of the collection phase seven collector modules are stored and sealed in a MIRKA-type sample return capsule.
SARIM will return the capsule containing the stardust to Earth to allow for an extraction and investigation of interstellar
samples by latest laboratory technologies. 相似文献
254.
Fault-propagation folding associated with an upward propagating fault in the Gilbertown graben system is revealed by well-based 3-D subsurface mapping and dipmeter analysis. The fold is developed in the Selma chalk, which is an oil reservoir along the southern margin of the graben. Area-depth-strain analysis suggests that the Cretaceous strata were growth units, the Jurassic strata were pregrowth units, and the graben system is detached in the Louann Salt.The growth trishear model has been applied in this paper to study the evolution and kinematics of extensional fault-propagation folding. Models indicate that the propagation to slip (p/s) ratio of the underlying fault plays an important role in governing the geometry of the resulting extensional fault-propagation fold. With a greater p/s ratio, the fold is more localized in the vicinity of the propagating fault. The extensional fault-propagation fold in the Gilbertown graben is modeled by both a compactional and a non-compactional growth trishear model. Both models predict a similar geometry of the extensional fault-propagation fold. The trishear model with compaction best predicts the fold geometry. 相似文献
255.
Tidal evolution of Mimas, Enceladus, and Dione 总被引:2,自引:0,他引:2
The tidal evolution through several resonances involving Mimas, Enceladus, and/or Dione is studied numerically with an averaged resonance model. We find that, in the Enceladus-Dione 2:1 e-Enceladus type resonance, Enceladus evolves chaotically in the future for some values of k2/Q. Past evolution of the system is marked by temporary capture into the Enceladus-Dione 4:2 ee′-mixed resonance. We find that the free libration of the Enceladus-Dione 2:1 e-Enceladus resonance angle of 1.5° can be explained by a recent passage of the system through a secondary resonance. In simulations with passage through the secondary resonance, the system enters the current Enceladus-Dione resonance close to tidal equilibrium and thus the equilibrium value of tidal heating of 1.1(18,000/QS) GW applies. We find that the current anomalously large eccentricity of Mimas can be explained by passage through several past resonances. In all cases, escape from the resonance occurs by unstable growth of the libration angle, sometimes with the help of a secondary resonance. Explanation of the current eccentricity of Mimas by evolution through these resonances implies that the Q of Saturn is below 100,000. Though the eccentricity of Enceladus can be excited to moderate values by capture in the Mimas-Enceladus 3:2 e-Enceladus resonance, the libration amplitude damps and the system does not escape. Thus past occupancy of this resonance and consequent tidal heating of Enceladus is excluded. The construction of a coherent history places constraints on the allowed values of k2/Q for the satellites. 相似文献
256.
In the restricted circular three-body problem, two massive bodies travel on circular orbits about their mutual center of mass and gravitationally perturb the motion of a massless particle. The triangular Lagrange points, L4 and L5, form equilateral triangles with the two massive bodies and lie in their orbital plane. Provided the primary is at least 27 times as massive as the secondary, orbits near L4 and L5 can remain close to these locations indefinitely. More than 2200 cataloged asteroids librate about the L4 and L5 points of the Sun-Jupiter system, and five bodies have been discovered around the L4 point of the Sun-Neptune system. Small satellites have also been found librating about the L4 and L5 points of two of Saturn's moons. However, no objects have been discovered around the Earth-Moon L4 and L5 points. Using numerical integrations, we show that orbits near the Earth-Moon L4 and L5 points can survive for over a billion years even when solar perturbations are included, but the further addition of the far smaller perturbations from other planets destabilize these orbits within several million years. Thus, the lack of observed objects in these regions cannot be used as a constraint on Solar System formation, nor on the tidal evolution of the Moon's orbit. 相似文献
257.
The main equations in the paper “Episodic volcanism of tidally heated satellites with application to Io” by Ojakangas and Stevenson [Icarus 66, 341-358] are presented; numerical integration of these equations confirms the results of Ojakangas and Stevenson [Icarus 66, 341-358] for Io. Application to Enceladus is considered. It is shown that Enceladus does not oscillate about the tidal equilibrium in this model by both new nonlinear stability analysis and numerical integration of the model equations. 相似文献
258.
Sadeghi G Schijven JF Behrends T Hassanizadeh SM Gerritse J Kleingeld PJ 《Ground water》2011,49(1):12-19
Objectives of this work are to investigate effects of pH and ionic strength (IS) on virus transport in saturated soil and to develop a quantitative relationship for these effects. A series of 50-cm column experiments with clean quartz sand under saturated conditions and with pH values of 5, 6, 7, 8, and IS values of 1, 10, and 20 mM were conducted. Bacteriophage PRD1 was used as a model virus. Applying a one-site kinetic model, attachment, detachment, and inactivation rate coefficients were determined from fitting breakthrough curves using the software package Hydrus-1D. Attachment rate coefficients increased with decreasing pH and increasing IS, in agreement with DLVO theory. Sticking efficiencies were calculated from the attachment rate coefficients and used to develop an empirical formula for sticking efficiency as a function of pH and IS. This relationship is applicable under unfavorable conditions for virus attachment. We compared sticking efficiencies predicted by the empirical formula with those from field and column experiments. Within the calibrated range of pH and IS, the predicted and observed sticking efficiencies are in reasonable agreement for bacteriophages PRD1 and MS2. However, the formula significantly overestimates sticking efficiencies for IS higher than 100 mM. In addition, it performs less well for viruses with different surface reactivity than PRD1 and MS2. Effects of pH and IS on detachment and inactivation rate coefficients were also investigated but the experimental results do not allow constraining these parameters with sufficient certainty. 相似文献
259.
J. H. M. M. Schmitt K.‐P. Schrder G. Rauw A. Hempelmann M. Mittag J. N. Gonzlez‐Prez S. Czesla U. Wolter D. Jack P. Eenens M. A. Trinidad 《Astronomische Nachrichten》2014,335(8):787-796
TIGRE is a new robotic spectroscopy telescope located in central Mexico at the La Luz Observatory of the University of Guanajuato. The 1.2 m telescope is fiber‐coupled to an ´echelle spectrograph with a spectral resolving power exceeding 20000 over most of the covered spectral range between 3800 Å and 8800 Å, with a small gap of 130 Å around 5800 Å. TIGRE operates robotically, i.e. it (normally) carries out all observations without any human intervention, including, in particular, the target selection in any given observing night. In this paper we describe the properties of the TIGRE instrumentation and its technical realization, as well as our first operational experience with the performance and efficiency of the overall system. Finally, we present some examples of recent TIGRE observations. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
260.
Michael R. Grose Stuart P. Corney Jack J. Katzfey James C. Bennett Gregory K. Holz Christopher J. White Nathaniel L. Bindoff 《Climate Dynamics》2013,40(7-8):2035-2048
Coupled ocean–atmosphere general circulation models (GCMs) lack sufficient resolution to model the regional detail of changes to mean circulation and rainfall with projected climate warming. In this paper, changes in mean circulation and rainfall in GCMs are compared to those in a variable resolution regional climate model, the Conformal Cubic Atmospheric Model (CCAM), under a high greenhouse gas emissions scenario. The study site is Tasmania, Australia, which is positioned within the mid-latitude westerlies of the southern hemisphere. CCAM projects a different response in mean sea level pressure and mid-latitude westerly circulation to climate warming to the GCMs used as input, and shows greater regional detail of the boundaries between regions of increasing and decreasing rainfall. Changes in mean circulation dominate the mean rainfall response in western Tasmania, whereas changes to rainfall in the East Coast are less related to mean circulation changes. CCAM projects an amplification of the dominant westerly circulation over Tasmania and this amplifies the seasonal cycle of wet winters and dry summers in the west. There is a larger change in the strength than in the incidence of westerly circulation and rainfall events. We propose the regional climate model displays a more sensitive atmospheric response to the different rates of warming of land and sea than the GCMs as input. The regional variation in these results highlight the need for dynamical downscaling of coupled general circulation models to finely resolve the influence of mean circulation and boundaries between regions of projected increases and decreases in rainfall. 相似文献