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501.
Understanding of the biochemical events in a chemo-bioreactor during continuous acid mine drainage treatment 总被引:1,自引:1,他引:0
Bidus Kanti Das Santi M. Mandal Jayanta Bhattacharya 《Environmental Earth Sciences》2012,66(2):607-614
Spent mushroom compost (SMC) is widely used as reactor matrix in passive bioreactor involving sulfate reducing bacteria (SRB)
for acid mine drainage (AMD) treatment. Follow-up our previous report, recent work has been established the extent of activity,
sustained organic carbon availability, and the biochemical events of successive alkalinity producing system-based chemo-bioreactor
for continuous performance using SMC. Removal of iron and sulfate from influent was over 77 and 90%, respectively, for first
13 weeks, while sulfate removal efficiency suddenly dropped down to 31% thereafter. Ahead of 13th week, process failure was
beginning to be noticed when available dissolved organic carbon (DOC) value dropped down to 50 mg/L. SRB population was mostly
affected with DOC drought at this stage. Sulfur was one of the major elements found with other tested metals in blackish green
effluent precipitate. Sulfide compounds of the tested metals were formed on both exhausted chemo-bioreactor bed and precipitate.
FTIR analysis indicated that SMC was responsible for metal binding and available nutrients supply. The present study revealed
the feasibility of SMC as a host for treating AMD by this chemo-bioreactor that will assist in designing the continuous treatment
practice. 相似文献
502.
Munshi Khaledur Rahman Bimal Kanti Paul Andrew Curtis Thomas W. Schmidlin 《The Professional geographer》2013,65(2):218-228
On 4 August 2012, the southeastern part of Kutubdia Island, Bangladesh, experienced coastal erosion and flooding associated with tidal waves, storms, and continuous heavy rainfall for two days. This provided a unique opportunity to study the relationship between rapid-onset disasters and migration decisions of individual households perpetually living under environmental risk. Using Kutubdia Island as a case study, this article examines the migration decisions of respondents in the immediate aftermath of two extreme natural events. Relevant data were primarily collected from a questionnaire survey conducted nearly two months after the occurrence of the event. The study's findings support the view that both environmental and nonenvironmental factors lead to migration. The article outlines several areas for further research on the links between migration and environmental stress. 相似文献
503.
Bimal Kanti Paul 《The Professional geographer》2013,65(3):401-414
Cyclone Sidr, a Category 4 storm, struck the southwestern coast of Bangladesh on 15 November 2007. Despite early cyclone warnings and emergency evacuation orders for coastal residents, thousands of individuals stayed in their homes. This study examines Sidr victims’ responses to cyclone warnings and evacuation orders, and explores the factors that would explain why the victims did or did not comply with the orders. Based on survey data collected from 277 Sidr survivors living in the four most severely impacted coastal districts, this study found that more than 75 percent of all respondents were aware of the cyclone warnings and evacuation orders before Sidr's landfall. Despite the efforts of the Bangladesh government, there were lapses in cyclone warnings and evacuation procedures. Field data also reveal several reasons cited by respondents for not complying with evacuation orders. Multivariate analyses of survey data show that trust in warning messages was the most important determinant in the decision to seek refuge in safer shelters, followed by distance to nearest shelter and annual level of education. Several recommendations have been made to improve cyclone warnings and the use of public shelters for similar future events. 相似文献
504.
Hussam Eldein Zaineh Hiroaki Yamanaka Yadab Prasad Dhakal Rawaa Dakkak Mohamad Daoud 《Journal of Seismology》2013,17(4):1295-1319
The seismic hazard potential for metropolitan of Damascus, Syria is mainly controlled by earthquakes along Serghaya Fault which is a branch of Dead Sea Fault System. In this study, strong ground motion due to the November 1759 Earthquake along the fault of Serghaya was estimated with a numerical simulation technique. In the simulation, the Kostrov-like slip-velocity function was used as an input to the discrete wave number method to simulate the strong ground motions in a broadband frequency range. In order to model the incoherent rupture propagation which can excite large high-frequency waves, random numbers are added to arrival time of circular rupture front. MMI intensities calculated from the synthetic ground motions are compared with the observed values by Ambraseys and Barazangi (J Geophys Res 94:4007-4013, 1989). The calculated intensities are in good agreement with the observed ones at the most sites that validate appropriateness of the proposed source model. The PGA and PGV in the eastern region of Damascus city are higher than those in the western region due to the effects of local site amplification. The simulated high-frequency (1.0–6.0 Hz) ground motions for the sites in the Damascus city are higher than the design requirements defined by the Syrian building code. Furthermore, the simulated high-frequency ground motions for sites in the focal region are bigger than the design requirements in the case of the near-fault factors and are not considered. That demonstrates the appropriateness of considering the near-fault factors for a site near the focal region as introduced by the new building code. 相似文献
505.
Oksana Sytar Marian Brestic Abhay Kumar M. N. V. Prasad Nataliya Taran Iryna Smetanska 《洁净——土壤、空气、水》2013,41(11):1129-1137
In this study, Fagopyrum esculentum (common buckwheat) sprayed with nickel (Ni) (0, 0.5, 1.0, 3.0, and 5.0 mM) for different duration has been investigated for Ni accumulation, malondialdehyde (MDA), total phenolics, and phenolic acids. Ni accumulation significantly increased in dose‐dependent manner. Plants exposed for 72 h, showed visible damages as chlorosis and irreversible necrosis. The MDA and total phenolic contents increased at 24 h of Ni treatments. HPLC data revealed that phenolic acids are in good correlation with concentration and durations of treatments. After 24 and 48 h the contents of chlorogenic, p‐hydroxybenzoic, hesperetic, p‐anisic, and caffeic acids increased in Ni treated leaves. On the other hand, p‐hydroxybenzoic, hesperetic, p‐anisic, p‐coumaric, caffeic acids contents decreased after 72 h of Ni exposure. Vanillic and cinnamic acid followed same pattern and increased significantly at 3.0 and 5.0 mM after 48 h of Ni exposure. It may suggest that buckwheat can be possible hyperaccumulators of Ni, because of high Ni accumulation in tissues through foliar treatment. Furthermore, the analyzed phenolic acids have potential role as antioxidants, which provide tolerance to buckwheat against Ni treatment. 相似文献
506.
507.
508.
Simultaneous observations of Stokes profiles in photospheric Fei (630.15 nm and 630.25 nm) and chromospheric Mgi b
1 and b
2 (518.4 nm and 517.3 nm) lines over a sunspot are presented. Observations were carried out using the Advanced Stokes Polarimeter of HAO/NSO, VTT, SacPeak, U.S.A. The Stokes-V amplitude asymmetries for these lines are analyzed. The values of amplitude asymmetry in Mgb lines are negative in disk-center-side penumbra while they are positive in limb-side penumbra. This trend is similar in nature to photospheric Fei line observations. Further, the spatial distribution of Stokes-V asymmetry is analyzed using Net Circular Polarization (NCP) maps. The chromospheric and photospheric NCP maps are different in many aspects. These observations with longitudinal magnetic field, estimated using weak field approximation, are discussed in this paper. 相似文献
509.
Prasad Subramanian B. S. Pujari Peter A. Becker 《Journal of Astrophysics and Astronomy》2004,25(1-2):81-91
We reexamine arguments advanced by Hayashi & Matsuda (2001), who claim that several simple, physically motivated derivations
based on mean free path theory for calculating the viscous torque in a quasi-Keplerian accretion disk yield results that are
inconsistent with the generally accepted model. If correct, the ideas proposed by Hayashi & Matsuda would radically alter
our understanding of the nature of the angular momentum transport in the disk, which is a central feature of accretion disk
theory. However, in this paper we point out several fallacies in their arguments and show that there indeed exists a simple
derivation based on mean free path theory that yields an expression for the viscous torque that is proportional to the radial
derivative of the angular velocity in the accretion disk, as expected. The derivation is based on the analysis of the epicyclic
motion of gas parcels in adjacent eddies in the disk. 相似文献
510.