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391.
N. K. Choudhary C. S. Agarwal D. K. Sharma 《Journal of the Indian Society of Remote Sensing》1988,16(1):29-39
The Fatehpur Sikri area infringing the western UP, Rajasthan border was investigated for its water supply crisis in respect of poor quality and quantity as well. The study has indicated presence of two parallel quartz reefs running in NE-SW direction. Geohydrological and photogeological studies have revealed the possibility of subsurface extension of quartz reefs. However, this weathered area along reefs is promising water bearing zone. Paleo channels are also marked during studies and the area found suitable for ground water exploitation. A map showing various categories is also presented. 相似文献
392.
393.
V. R. S. Mani 《Journal of the Geological Society of India》2018,91(5):541-546
With the availability of multi sensor data in many fields, such as remote sensing, medical imaging or machine vision, sensor fusion has emerged as a new and promising research area. It is possible to have several images of the same scene providing different information although the scene is the same. This is because each image has been captured with a different sensor. A non-negative matrix factorization (NNMF) un mixing based fusion technique with vertex component analysis (VCA) based end member initialization and simple multiplicative update to improve the spatial resolution and to preserve the spectral resolution of the hyper spectral image is proposed. Its performance is analyzed with different number of iterations and end member initializations. A Constrained Non Negative Matrix Factorization unmixing based fusion technique is developed by adding a regularization term to the objective function to preserve the spectral resolution of the hyper spectral image, and its performance is analyzed with different number of iterations and end members. A rank two NNMF and hierarchical clustering based end member initialization and block principal pivoting algorithm based abundance estimation technique, for fusing hyper spectral image and simulated multispectral image is proposed and its performance is analyzed for different overlapping and non overlapping group of multispectral and hyper spectral bands. The performance of the above three methods are compared and analyzed. The obtained results show that the performance of rank two NNMF hierarchical clustering based fusion technique is better than the other two constrained and unconstrained NNMF un mixing based techniques. Also, the performance of these three proposed multi sensor image fusion techniques are compared with an existing image fusion technique. 相似文献
394.
To begin exploring the underlying mechanisms that couple vegetation to cloud formation processes, we derive the lifting condensation
level (LCL) to estimate cumulus cloud base height. Using a fully coupled land–ocean–atmosphere general circulation model (HadCM3LC),
we investigate Amazonian forest feedbacks on cloud formation over three geological periods; modern-day (a.d. 1970–1990), the last glacial maximum (LGM; 21 kya), and under a future climate scenario (IS92a; a.d. 2070–2090). Results indicate that for both past and future climate scenarios, LCL is higher relative to modern-day. Statistical
analyses indicate that the 800 m increase in LCL during the LGM is related primarily to the drier atmosphere promoted by lower
tropical sea surface temperatures. In contrast, the predicted 1,000 m increase in LCL in the future scenario is the result
of a large increase in surface temperature and reduced vegetation cover. 相似文献
395.
Astronomy Letters - The formation of the rubidium resonance lines is considered by taking into account the effects of departures from local thermodynamic equilibrium (LTE). A rubidium model atom... 相似文献
396.
In this work we present and discuss the results of ambient seismic noise analyses computed at four sites where seismic stations,
managed by the INGV (Italian Institute for Geophysics and Vulcanology) and the DPC (Italian Department of Civil Protection), are installed inside buildings. The experiments were performed considering different types of installation: sensor located
at the bottom of a school, directly installed on rock (case 1); sensor located at the bottom of a medieval fortress, built
on an isolate hill, directly installed on rock (case 2); sensor installed on the foundations of a medieval fortress, built
on an isolate hill (case 3); sensor installed on the foundations of a school, built on alluvial deposits (case 4). Since recent
works proposed the use of spectral ratio techniques to study the dynamic characterization of buildings, ambient seismic-noise
measurements were performed for each site close to the stations (at the base of the structures), at the top of the structures
and outside the buildings. In order to check the source of vibrations both horizontal to vertical spectral ratio (HVNR) and
standard spectral ratio (SSR) techniques were applied. For all stations the results from ambient seismic noise were compared
to those obtained from earthquakes (HVSR). In order to detect preferential directions of amplification, for each site average
HVNRs and HVSRs were computed considering one azimuth for each set of 5°. We obtain different results for different types
of installation: in cases 1 and 2, where the sensors are directly installed on rock, the vibrations of the structure do not
affect the noise measures performed close to the stations, which show flat HVNR in the whole frequency range: in both cases
the eigenfrequency of the building is given by the HVNR calculated from the measures performed at the top of the structure.
In cases 3 and 4, where the sensors are installed on the foundations of the considered structures, both the amplification
peaks between 5 and 9 Hz (case 3) and between 5.5 and 7 Hz (case 4) include the contribution of the free oscillations of the
buildings. In particular, in case 4, HVNRs performed outside building highlight possible soil–structure resonance effects
in case of an earthquake. 相似文献
397.
In this paper we apply 3D inversion to MT data collected in the Northwestern United States as a part of the EarthScope project.
By the end of 2009 MT data had been collected from 262 stations located throughout Oregon, Washington, Idaho, and most of
Montana and Wyoming. We used data from 139 MT stations in this analysis. We developed fully parallelized rigorous 3D MT inversion
software based on the integral equation method with variable background conductivity. We also implemented a receiver footprint
approach which considerably reduced the computational resources needed to invert the large volumes of data covering vast areas.
The data set used in the inversion was obtained through the Incorporated Research Institutions for Seismology (IRIS). The
inversion domain was divided into 2.7 M cells. The inverted electrical conductivity distribution agrees reasonably well with
geological features of the region. 相似文献
398.
A thermal event reduces the number of previously registered fission tracks in a mineral dependent upon the track retention properties of the individual mineral. Apatite, sphene and zircon have retention properties over a wide range of temperatures (from 100° to 550°C); apatite data reveal information at lowest temperatures while sphene and zircon data are useful for higher temperatures.Thermal events within this temperature range of 100°C to about 550°C are suitable for study with this technique. The age of the event is determined from samples in which the fission tracks are completely erased, while minerals containing partially removed (erased) tracks provide information on the temperatures occurring during the thermal event.As a test case, the analysis of the temperatures developed by the meteorite impact which produced the Ries crater at 14.7 m.y. ago is presented. 相似文献
399.
Chinmay Mallik S. Venkataramani Shyam Lal 《Asia-Pacific Journal of Atmospheric Sciences》2012,48(2):171-180
Continuous measurements of SO2, NOx and O3 along with sampling based measurements of CO, CH4, NMHCs and CO2 were carried out during May, 2010 at Ahmedabad. The diurnal variations of SO2 in ambient air exhibited elevated values during the night and lower levels during the sunlit hours. The mean concentration of SO2 during the study period was 0.95 ± 0.88 ppbv. However, the ambient SO2 exceeded 17 ppbv in the night of 20 May, 2010. On the same day, tropospheric columnar SO2 from OMI showed almost 350% increase corroborating the surface observations over an extended height regime. This was also the highest columnar value of SO2 during the summer of 2010. Columnar loadings were also found to be high for formaldehyde, precipitable water vapor and aerosol optical depth on 20 May. Elevated concentrations were also recorded for other trace gases like NO2 and O3. Analysis of related data of trace gases indicated characteristics of fresh emissions with dominant contributions from mobile sources during the study period. However, SO2/NO2 ratio of 0.36 during the event period on 20th May connotes non-local influences. Analyses of meteorological parameters suggest combined impacts of transport and inversion causing higher levels of SO2 and other pollutants during 20?C21 May. Episodes of such enhancements may perturb chemical and radiative balance of the atmosphere. 相似文献
400.