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51.
The relative intensities of anhysteretic remanent magnetization (RAM) and thermoramanent magnetization (TRM) are strongly dependent on grain size, blocking temperature and applied field, and are poorly predicted by existing theories. Analog techniques that substitute ARM for TRM probably yield adequate relative paleointensities in suites of mineralogically similar rocks, but they yield uncertain estimates of absolute paleointensity. 相似文献
52.
A transect of the St Marys River estuary from above the point of maximum salt wedge penetration to coastal salinities was
conducted in July 1999. None of the parameters examined—dissolved organic carbon (DOC) content, UV light absorbance at 254
nm, and Total Luminescence spectra—follow the rule of conservative mixing. The characteristics of the different molecular
size fractions of the St Marys River natural organic matter (NOM), as well as the results of a laboratory mixing experiment,
provided evidence that loss of larger molecular size compounds from riverine NOM may occur by coagulation at salinities up
to 10. An apparent gain of carbon in the lower estuary was attributed to exports from abundant coastal marshes in this area.
The Total Luminescence spectra of the riverine NOM can be described by two peaks, centered respectively around 340/445 nm,
and 230/430 nm Excitation/Emission Wavelength Pair (EEWP), which are characteristic of humic materials of aquatic origin.
The samples from the high salinity stations exhibit peaks at lower emission wavelength EEWP 320/424 nm, which can be considered
as marine humic-like material. The presence of amino acid-tryptophan like peaks were observed, with EEWP 300/350 nm in some
of the high salinity samples. This peak was of high relative fluorescence intensity. It is hypothesized that the intense biological
activity of the salt marsh and near coastal area is responsible for the carbon addition as well as the appearance of the highly
fluorescence amino acid-protein like material. 相似文献
53.
54.
Isa Baud Monika Kuffer Karin Pfeffer Richard Sliuzas Sadasivam Karuppannan 《International Journal of Applied Earth Observation and Geoinformation》2010
Analyzing the heterogeneity in metropolitan areas of India utilizing remote sensing data can help to identify more precise patterns of sub-standard residential areas. Earlier work analyzing inequalities in Indian cities employed a constructed index of multiple deprivations (IMDs) utilizing data from the Census of India 2001 (http://censusindia.gov.in). While that index, described in an earlier paper, provided a first approach to identify heterogeneity at the citywide scale, it neither provided information on spatial variations within the geographical boundaries of the Census database, nor about physical characteristics, such as green spaces and the variation in housing density and quality. In this article, we analyze whether different types of sub-standard residential areas can be identified through remote sensing data, combined, where relevant, with ground-truthing and local knowledge. The specific questions address: (1) the extent to which types of residential sub-standard areas can be drawn from remote sensing data, based on patterns of green space, structure of layout, density of built-up areas, size of buildings and other site characteristics; (2) the spatial diversity of these residential types for selected electoral wards; and (3) the correlation between different types of sub-standard residential areas and the results of the index of multiple deprivations utilized at electoral ward level found previously. 相似文献
55.
Despite a long-term focus on learning in natural resource management (NRM), it is still debated how learning supports sustainable real-world NRM practices. We offer a qualitative in-depth synthesis of selected scientific empirical literature (N?=?53), which explores factors affecting action-oriented learning. We inductively identify eight key process-based and contextual factors discussed in this literature. Three patterns emerge from our results. First, the literature discusses both facilitated participation and self-organized collaboration as dialogical spaces, which bridge interests and support constructive conflict management. Second, the literature suggests practice-based dialogs as those best able to facilitate action and puts a strong emphasis on experimentation. Finally, not emphasized in existing reviews and syntheses, we found multiple evidence about certain contextual factors affecting learning, including social-ecological crises, complexity, and power structures. Our review also points at important knowledge gaps, which can be used to advance the current research agenda about learning and NRM. 相似文献
56.
Agata M. Krzesiska Richard Wirth Monika A. Kusiak 《Meteoritics & planetary science》2019,54(7):1462-1477
Zak?odzie is an enstatite meteorite of unknown petrogenesis. Chemically, it resembles enstatite chondrites, but displays an achondrite‐like texture. Here we report on fabric and texture analyses of Zak?odzie utilizing X‐ray computed tomography and scanning electron microscopy and combine it with a nanostructural study of striated pyroxene by transmission electron microscopy. With this approach we identify mechanisms that led to formation of the texture and address the petrogenesis of the rock. Zak?odzie experienced a shock event in its early evolution while located at some depth inside a warm parent body. Shock‐related strain inverted pyroxene to the observed mixture of intercalated orthorhombic and monoclinic polymorphs. The heat that dissipated after the peak shock was added to primary, radiogenic‐derived heat and led to a prolonged thermal event. This caused local, equilibrium‐based partial melting of plagioclase and metal‐sulfide. Partial melting was followed by two‐stage cooling. The first phase of annealing (above 500 °C) allowed for crystallization of plagioclase and for textural equilibration of metal and sulfides with silicates. Below 500 °C, cooling was faster and more heterogeneous at cm scale, allowing retention of keilite and quenching of K‐rich feldspathic glass in some parts. Our study indicates that Zak?odzie is neither an impact melt rock nor a primitive achondrite, as suggested in former studies. An impact melt origin is excluded because enstatite in Zak?odzie was never completely melted and partial melting occurred during equilibrium‐based postshock conditions. Texturally, the rock represents a transition of chondrite and achondrite and was formed when early impact heat was added to internal radiogenic heat. 相似文献
57.
Amit Mittal Rajiv Agarwal Md Sanam Suraj Monika Arora 《Astrophysics and Space Science》2018,363(5):109
This paper deals with the photo-gravitational restricted four-body problem (PR4BP) with variable mass. Following the procedure given by Gascheau (C. R. 16:393–394, 1843) and Routh (Proc. Lond. Math. Soc. 6:86–97, 1875), the conditions of linear stability of Lagrange triangle solution in the PR4BP are determined. The three radiating primaries having masses \(m_{1}\), \(m_{2}\) and \(m_{3}\) in an equilateral triangle with \(m_{2}=m_{3}\) will be stable as long as they satisfy the linear stability condition of the Lagrangian triangle solution. We have derived the equations of motion of the mentioned problem and observed that there exist eight libration points for a fixed value of parameters \(\gamma (\frac{m \ \text{at time} \ t}{m \ \text{at initial time}}, 0<\gamma\leq1 )\), \(\alpha\) (the proportionality constant in Jeans’ law (Astronomy and Cosmogony, Cambridge University Press, Cambridge, 1928), \(0\leq\alpha\leq2.2\)), the mass parameter \(\mu=0.005\) and radiation parameters \(q_{i}, (0< q_{i}\leq1, i=1, 2, 3)\). All the libration points are non-collinear if \(q_{2}\neq q_{3}\). It has been observed that the collinear and out-of-plane libration points also exist for \(q_{2}=q_{3}\). In all the cases, each libration point is found to be unstable. Further, zero velocity curves (ZVCs) and Newton–Raphson basins of attraction are also discussed. 相似文献
58.
59.
Paulina Rusanowska Monika Harnisz Marcin Zieliski Marcin Dbowski Ewa Korzeniewska Marta Kisielewska Ewa Amenda 《洁净——土壤、空气、水》2020,48(2)
Methane fermentation is widely used to dispose of sewage sludge at wastewater treatment plants (WWTPs), due to production of renewable energy in the form of biogas. Antibiotics present in wastewater may accumulate in a sewage sludge. The aim of the present study is to investigate the impact of three antibiotics from different classes in three different doses on methane production from sewage sludge. For this purpose, metronidazole (MET), amoxicillin (AMO), and ciprofloxacin (CIP) are individually added to anaerobic reactors with sewage sludge collected from municipal WWTP. The antibiotics’ highest concentration (1024 mg kg?1 of AMO; 512 mg kg?1 of MET and CIP) lowers methane production and methane content in biogas. MET exerts the most marked effect and lowers methane production to 36.8 ± 3.7 mL CH4 kg?1 volatile solids. Tested antibiotics probably inhibit methanogenic archaea, which results in volatile fatty acids (VFAs) accumulation. Addition of MET results in accumulation of many kinds of VFAs with the highest concentration of acetic acid (17.52 ± 1.85 g L?1). The addition of of AMO results in accumulation of butyric acid only (253.00 ± 15.89 g L?1). However, addition of CIP results in accumulation of mainly acetic acid (7.58 ± 0.82 g L?1) and isovaleric acid (2.01 ± 0.41 g L?1). Next, synergistic effect of these antibiotics in a low concentration of 16 mg kg?1 of AMO, 8 mg kg?1 of MET, and 2 mg kg?1 of CIP is measured in semi‐continuous conditions and causes inbibition of methane production and accumulation of VFAs. 相似文献
60.
Feasibility of utilizing wavelet phase to map the CO2 plume at the Ketzin pilot site,Germany 下载免费PDF全文
Fei Huang Christopher Juhlin Li Han Daniel Sopher Monika Ivandic Ben Norden Wubing Deng Fengjiao Zhang Thomas Kempka Stefan Lüth 《Geophysical Prospecting》2017,65(2):523-543
Spectral decomposition is a powerful tool that can provide geological details dependent upon discrete frequencies. Complex spectral decomposition using inversion strategies differs from conventional spectral decomposition methods in that it produces not only frequency information but also wavelet phase information. This method was applied to a time‐lapse three‐dimensional seismic dataset in order to test the feasibility of using wavelet phase changes to detect and map injected carbon dioxide within the reservoir at the Ketzin carbon dioxide storage site, Germany. Simplified zero‐offset forward modelling was used to help verify the effectiveness of this technique and to better understand the wavelet phase response from the highly heterogeneous storage reservoir and carbon dioxide plume. Ambient noise and signal‐to‐noise ratios were calculated from the raw data to determine the extracted wavelet phase. Strong noise caused by rainfall and the assumed spatial distribution of sandstone channels in the reservoir could be correlated with phase anomalies. Qualitative and quantitative results indicate that the wavelet phase extracted by the complex spectral decomposition technique has great potential as a practical and feasible tool for carbon dioxide detection at the Ketzin pilot site. 相似文献