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851.
Vulnerability assessment in a volcanic risk evaluation in Central Mexico through a multi-criteria-GIS approach 总被引:1,自引:1,他引:1
José Fernando Aceves-Quesada Jesús Díaz-Salgado Jorge López-Blanco 《Natural Hazards》2007,40(2):339-356
The Valley of Toluca is a major industrial and agricultural area in Central Mexico, especially the City of Toluca, the capital
of The State of Mexico. The Nevado de Toluca volcano is located to the southwest of The Toluca Basin. Results obtained from
the vulnerability assessment phase of the study area (5,040 km2 and 42 municipalities) are presented here as a part of a comprehensive volcanic risk assessment of The Toluca Basin. Information
has been gathered and processed at a municipal level including thematic maps at 1:250,000 scale. A database has been built,
classified and analyzed within a GIS environment; additionally, a Multi-Criteria Evaluation (MCE) approach was applied as
an aid for the decision-making process. Cartographic results were five vulnerability maps: (1) Total Population, (2) Land
Use/Cover, (3) Infrastructure, (4) Economic Units and (5) Total Vulnerability. Our main results suggest that the Toluca and
Tianguistenco urban and industrial areas, to the north and northeast of The Valley of Toluca, are the most vulnerable areas,
for their high concentration of population, infrastructure, economic activity, and exposure to volcanic events. 相似文献
852.
Uwe Mikolajewicz Matthias Gröger Ernst Maier-Reimer Guy Schurgers Miren Vizcaíno Arne M. E. Winguth 《Climate Dynamics》2007,28(6):599-633
A new complex earth system model consisting of an atmospheric general circulation model, an ocean general circulation model,
a three-dimensional ice sheet model, a marine biogeochemistry model, and a dynamic vegetation model was used to study the
long-term response to anthropogenic carbon emissions. The prescribed emissions follow estimates of past emissions for the
period 1751–2000 and standard IPCC emission scenarios up to the year 2100. After 2100, an exponential decrease of the emissions
was assumed. For each of the scenarios, a small ensemble of simulations was carried out. The North Atlantic overturning collapsed
in the high emission scenario (A2) simulations. In the low emission scenario (B1), only a temporary weakening of the deep
water formation in the North Atlantic is predicted. The moderate emission scenario (A1B) brings the system close to its bifurcation
point, with three out of five runs leading to a collapsed North Atlantic overturning circulation. The atmospheric moisture
transport predominantly contributes to the collapse of the deep water formation. In the simulations with collapsed deep water
formation in the North Atlantic a substantial cooling over parts of the North Atlantic is simulated. Anthropogenic climate
change substantially reduces the ability of land and ocean to sequester anthropogenic carbon. The simulated effect of a collapse
of the deep water formation in the North Atlantic on the atmospheric CO2 concentration turned out to be relatively small. The volume of the Greenland ice sheet is reduced, but its contribution to
global mean sea level is almost counterbalanced by the growth of the Antarctic ice sheet due to enhanced snowfall. The modifications
of the high latitude freshwater input due to the simulated changes in mass balance of the ice sheet are one order of magnitude
smaller than the changes due to atmospheric moisture transport. After the year 3000, the global mean surface temperature is
predicted to be almost constant due to the compensating effects of decreasing atmospheric CO2 concentrations due to oceanic uptake and delayed response to increasing atmospheric CO2 concentrations before. 相似文献
853.
Sea/land breeze climatological characteristics along the northern Croatian Adriatic coast 总被引:1,自引:0,他引:1
Summary Climatological characteristics along the northern Croatian Adriatic coast have been examined for nine meteorological stations
for the summertime sea/land breeze circulation. The stations considered are Pula-airport, Opatija, Rijeka, Senj, Malinska,
Rijeka-airport, Mali Lošinj, Rab and Zadar. The hourly surface measurements at each station from June to September for the
period 1991–2004 as well as the radiosoundings in Zadar (from 2002 to 2004) were used for the analysis. A dataset with the
sea/land breeze days was formed according to the several criteria.
The mean daily maxima of both air and sea surface temperatures were more influenced by the large scale disturbances toward
north (e.g. in Rijeka or Opatija) compared to the values for e.g. Zadar. Furthermore, the influence of the large scale disturbances
diminished toward the south concerning the sea–land temperature difference only at the stations placed at Rijeka Bay and Velebit
channel. The strongest sea breeze was found at Pula-airport and the most frequent ones at Opatija and Zadar. At Senj the rarest,
the weakest and the shortest sea breeze was observed. The climatological records of wind speed and air-sea temperature difference
(ΔT) showed for Opatija, Malinska and Zadar that the maximum measured wind speed is around 4.5 °C confirming the nonlinear relationship
between the sea breeze speeds and the ΔT during the day.
At most stations, the clockwise rotation of the hodographs prevails which is typical for the Northern hemisphere due to Coriolis
force, with the exception at Senj and Malinska. While the hodographs for Pula, Rijeka-airport and Mali Lošinj display a later
onset of the prevailing sea breeze because of the interaction among several sea breeze circulations, the results for Opatija,
Zadar and Senj show considerably distorted hodographs because of the nearby channeling of the air flow. 相似文献
854.
Summary “Koshava” is a gusty wind of changeable intensity, blowing from a south-easterly direction, over Serbia, Romania and Bulgaria.
It is caused by the interaction between the synoptic circulation and the orography of the Carpathian and the Balkan mountains.
This paper analyzes wind data measured at the Belgrade-Observatory during the longest period of consecutive days of “Koshava”
which occurred from 14 January to 13 February 1972. Mean hourly wind speed data has been examined using spectral analysis.
The power spectra are calculated using autocorrelation spectral analysis, the multi-taper method and wavelet transform. The
maximum of which is about 122 h (5 days) corresponds to the time span of synoptic processes. 相似文献
855.
Qunying Luo William Bellotti Martin Williams Ian Cooper Brett Bryan 《Climatic change》2007,85(1-2):89-101
This study presents a model-based risk assessment of wheat production under projected climate change by 2080 in eight locations
of South Australia. The vulnerability of wheat production under future climate change was quantitatively evaluated via a risk
analysis in which the identification of critical yield thresholds applies. Research results show that risk (conditional probability
of not exceeding the critical yield thresholds) increased more or less across all locations under the most likely climate
change. Wheat production in drier areas such as Minnipa, Orroroo and Wanbi will not be economically viable under the most
likely climate change. Intensive studies on adaptation are now required. 相似文献
856.
This paper introduces, explains, and describes methods for addressing the issues of permanence, leakage, and additionality
(PLA) of agricultural soil carbon sequestration (ASCS) activities at the project level. It is important to cast these as project-level
issues, because they relate to the integrity and consistency of using location-specific ASCS projects as an offset against
GHG emissions generated in other sectors (e.g., energy). The underlying objective is to understand and quantify what the net
carbon benefits of an ASCS project are once we account for the fact that (1) the sequestered carbon may be stored impermanently,
(2) the project may displace emissions outside the project boundaries (leakage), and (3) the project’s carbon sequestration
may not be entirely additional to what would have occurred anyway under business-as-usual (no project) conditions. This article
evaluates methods for identifying and estimating PLA and gauges the potential magnitude of these effects on the economic returns
to a project.
This work reflects ongoing collaborative efforts of the authors and Bruce McCarl (Texas A&M University), Allan Sommer, Jui-Chen
Yang, and Laurel Clayton (RTI International), Sandra Brown (Winrock International), Ken Andrasko and Ben DeAngelo (US EPA),
and various participants in the World Resources Institute/World Business Council workgroup to develop GHG project reporting
protocols. All opinions, errors and omissions are those of the authors only. 相似文献
857.
Angel F. Nieto-Samaniego María de Jesús Paulina Olmos-Moya Gilles Levresse Susana A. Alaniz-Alvarez Fanis Abdullin Alexis del Pilar-Martínez 《International Geology Review》2020,62(3):311-319
ABSTRACTThe Mesa Central of Mexico (MC) is an elevated plateau located 2000 m above sea level in central Mexico, where intrusions outcrop that register the history of exhumation-erosion occurring during the Late Cretaceous-Paleogene. The tectonic history of the region records formation of the Late Cretaceous-Paleogene ‘Mexican orogen’; this was followed by extension of the entire region and several plutons were then exhumed. The age and magnitude of the crustal uplift and erosion occurring during exhumation has not been addressed to date. Therefore, this study reports the crystallization and cooling ages of two plutons, the Tesorera Granodiorite and the Comanja Granite, and estimates their emplacement depths. Based on these data, the exhumation age of the Tesorera Granodiorite is estimated to be between ~73 Ma and ~63 Ma at an exhumation rate of ~528 m/m. y. and that of the Comanja Granite is 52 Ma and 48 Ma at an exhumation rate of ~2500 m/m. y. Exhumation-erosion event of the Tesorera Granodiorite was located on the trace of the San Luis-Tepehuanes Fault System and that of the Comanja Granite on the a trace of the El Bajío Fault System. Furthermore, the high exhumation rate in the Comanja Granite suggests that gravitational collapse played an important role during exhumation. 相似文献
858.
Rodríguez-Pacheco J. Sequeiros J. Del Peral L. Bronchalo E. Cid C. 《Solar physics》1998,181(1):185-200
The most intense energetic particle (mainly proton) events in the energy range 36–1600 keV, during the years of maximum activity of solar cycle 21 (1978 to 1982), have been studied with regard to their spectra, temporal profiles, source location at the Sun, interplanetary plasma parameters and interplanetary magnetic field topology. In all the events, the particles were accelerated by the 'Diffusive Shock' acceleration mechanism, because all the events were 'long-duration events', shock-associated, and their spectra fitted to a power-law energetic particle spectrum dJ/dE E-\gamma with the exponent values ranging from 1.25 up to 1.94, with a mean value of 1.60 ± 0.06. We also show that the spectral indexes are related to the shock properties by a linear expression. The solar sources were located on a wide longitudinal belt extending from 50^ W up to 73^ E. Neither the spectral indexes nor the shock parameters present any dependence on the source location at the Sun. Finally, only one event showed the complete set of properties that characterize the presence of a magnetic cloud associated with the event. 相似文献
859.
Roša D. Vršnak B. Božić H. Brajša R. Ruždjak V. Schroll A. Wöhl H. 《Solar physics》1998,179(2):237-252
The dependence of the measured apparent synodic solar rotation rate on the height of the chosen tracer is studied. A significant error occurs if the rotation rate is determined by tracing the apparent position of an object above the photospheric level projected on the solar disc. The centre-to-limb variation of this error can be used to determine simultaneously the height of the object and the true synodic rotation rate. The apparent (projected) heliographic coordinates are presented as a function of the height of the traced object and the coordinates of its footpoint. The relations obtained provide an explicit expression for the apparent rotation rate as a function of the observed heliographic coordinates of the tracer, enabling an analytic least-squares fit expression to determine simultaneously the real synodic rotation rate and the height of the tracer. 相似文献
860.
Martin G. Haehnelt Priyamvada Natarajan & Martin J. Rees 《Monthly notices of the Royal Astronomical Society》1998,300(3):817-827
We demonstrate that the luminosity function of the recently detected population of actively star-forming galaxies at redshift z = 3 and the B -band luminosity function of quasi-stellar objects (QSOs) at the same redshift can both be matched with the mass function of dark matter haloes predicted by standard variants of hierarchical cosmogonies for lifetimes of optically bright QSOs anywhere in the range 106 to 108 yr. There is a strong correlation between the lifetime and the required degree of non-linearity in the relation between black hole and halo mass. We suggest that the mass of supermassive black holes may be limited by the back-reaction of the emitted energy on the accretion flow in a self-gravitating disc. This would imply a relation of black hole to halo mass of the form M bh ∝ v 5 halo ∝ M 5/3 halo and a typical duration of the optically bright QSO phase of a few times 107 yr. The high integrated mass density of black holes inferred from recent black hole mass estimates in nearby galaxies may indicate that the overall efficiency of supermassive black holes for producing blue light is smaller than previously assumed. We discuss three possible accretion modes with low optical emission efficiency: (i) accretion at far above the Eddington rate, (ii) accretion obscured by dust, and (iii) accretion below the critical rate leading to an advection-dominated accretion flow lasting for a Hubble time. We further argue that accretion with low optical efficiency might be closely related to the origin of the hard X-ray background and that the ionizing background might be progressively dominated by stars rather than QSOs at higher redshift. 相似文献