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141.
Kanchan Wakadikar Avik Sil Niranjan Kolekar Shalini Tandon Rakesh Kumar 《Environmental Earth Sciences》2011,64(1):25-28
Drilling fluids are used for drilling natural gas, oil and water wells. These spill over into the surrounding soil at the
point of drilling, which may impair soil health. A laboratory investigation was carried out to determine the effect of non
aqueous drilling fluid (NADF) and synthetic base oil used with it on soil health as indicated by the dehydrogenase activity.
A non-sterile sandy loam soil was treated with different amounts of NADF and base oil at a rate of 800, 8,000 and 16,000 mg kg−1. Initially, reduction in dehydrogenase activity was observed, but it increased with the incubation time. On the 60th day
of incubation dehydrogenase activity in untreated control was 1.04 mg TPF g−1 h−1 whereas in the soil samples treated with NADF and the base oil (16,000 mg kg−1), the activity was 1.53 mg TPF h−1 and 1.90 mg TPF h−1, respectively, which was 72 and 82% more than in untreated control. Base oil-treated soil showed more dehydrogenase activity
than that observed with NADF. Both NADF and base oil stimulated the soil dehydrogenase activity. 相似文献
142.
The effects of plan-wise distribution of stiffness and strength-as determined by the number, location, orientation and yield deformations of resisting elements-on the inelastic response of one-storey systems are evaluated. In particular, various systems are investigated for wide ranges of parameters involved, with the objective of establishing how the response is influenced by: (i) the presence of resisting elements perpendicular to the direction of ground motion; (ii) the number of resisting elements along the direction of ground motion; (iii) the overstrength typical of code-designed buildings; (iv) the relative values of strength and stiffness eccentricities; and (v) whether the asymmetry of the system is due to eccentricity in stiffness or in mass. The results presented for a simple excitation make it possible to explain the inconsistencies in conclusions from various earlier investigations, and to evaluate their applicability to actual buildings. 相似文献
143.
Rakesh J. Pillai I. Bushra R. G. Robinson 《Geotechnical and Geological Engineering》2013,31(2):801-808
Clays treated with lower cement contents often exhibit behaviour similar to stiff clays with planar failure surface under triaxial compression. In the present work the behaviour of a marine clay treated with 5 % cement, subjected to undrained triaxial compression tests is studied. The pre-consolidation pressure of the cemented clay due to the cementation bonding is observed to be very high. It is attempted to model the behaviour of cement treated clay using a bounding surface plasticity formulation as the plastic behaviour of the cemented clays within the yield surface has to be considered. The effect of cementation is included in the model as the pre-consolidation pressure obtained from consolidation tests. The tensile strength due to cementation bonds is included in the equation of the bounding surface. Simulations of the undrained triaxial compression tests on cemented clays are carried out and the results are validated with the experimental results. 相似文献
144.
Pijush Pal Roy Chhangte Sawmliana Rakesh Kumar Singh 《Geotechnical and Geological Engineering》2016,34(3):901-909
Directives from the Hon’ble Supreme Court of India led to the banning of mining activities within a radius of 2 km of the Sri Jambunatheswara ancient temple in Hospet taluk of Karnataka State of India. On recommendation of the Department of Archaeology & Museums, Government of Karnataka, CSIR-CIMFR undertook extensive investigations wherein the ground vibration and air overpressure due to blasting in nearby iron ore mines were monitored to assess their damage and annoyance potentials. The magnitudes of blast-induced ground vibration and air-overpressure recorded in the temple were found to be within the standard safe limits stipulated by the Directorate General of Mines Safety, India when trial blasts were carried out at a distance greater than 290 m from the temple. When blasts were conducted at a distance of beyond 845 m from the temple, neither vibration nor sound of blasting could be recorded or heard at the temple premises, indicating it a safe zone for blasting. After thorough analyses of the recorded data, precise blast design parameters were recommended for blasting at distances beyond 200 m from the temple and allowing this distance to be demarcated as the safe zone where controlled blasting could ensure safety of the ancient temple. 相似文献
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GPS Solutions - A method for constructively using non-line-of-sight GNSS signals from a snapshot of signal samples for positioning of users in urban areas is presented here. Using a 3D building... 相似文献
150.
Rakesh Mazumder 《天文和天体物理学研究(英文版)》2019,(6):43-50
A filament is a cool, dense structure suspended in the solar corona. The eruption of a filament is often associated with a coronal mass ejection(CME), which has an adverse effect on space weather. Hence,research on filaments has attracted much attention in the recent past. The tilt angle of active region(AR)magnetic bipoles is a crucial parameter in the context of the solar dynamo, which governs the conversion efficiency of the toroidal magnetic field to poloidal magnetic field. Filaments always form over polarity inversion lines(PILs), so the study of tilt angles for these filaments can provide valuable information about generation of a magnetic field in the Sun. We investigate the tilt angles of filaments and other properties using McIntosh Archive data. We fit a straight line to each filament to estimate its tilt angle. We examine the variation of mean tilt angle with time. The latitude distribution of positive tilt angle filaments and negative tilt angle filaments reveals that there is a dominance of positive tilt angle filaments in the southern hemisphere and negative tilt angle filaments dominate in the northern hemisphere. We study the variation of the mean tilt angle for low and high latitudes separately. Investigations of temporal variation with filament number indicate that total filament number and low latitude filament number vary cyclically, in phase with the solar cycle. There are fewer filaments at high latitudes and they also show a cyclic pattern in temporal variation. We also study the north-south asymmetry of filaments with different latitude criteria. 相似文献