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61.
We investigate here the fluctuations in the total, open and closed solar magnetic flux (SMF) for the period 1971–1999 by means of the maximum entropy method in the frequency range 5×10−9–10−7 Hz (6 yr to 120 days). We use monthly data for the total, open and closed magnetic solar fluxes. Periodicities found in the series are similar showing that there is some relationship between the fluxes. The most important finding of this work is the existence of fluctuations at around 1.3 and 1.7 yr in the SMF with alternating importance during consecutive even and odd solar cycles. These fluctuations are directly related with variations present in cosmic rays, solar wind parameters and geomagnetic activity indexes. A quasi-triennial periodicity previously found in sunspots and other solar phenomena is also of importance. The SMF is generated by the action of the solar dynamo; therefore, it is through the magnetic flux that the solar dynamo influences several heliospheric phenomena. 相似文献
62.
63.
Using the annual number of geomagnetically quiet days (aa < 20 γ) for the year after the solar minimum, this precursor method predicts that the maximum sunspot number for cycle 23 will be 140 + 32, indicating that cycle 23 will be similar to cycles 21 and 22. 相似文献
64.
Jasper van Vliet Andries F. Hof Angelica Mendoza Beltran Maarten van den Berg Sebastiaan Deetman Michel G. J. den Elzen Paul L. Lucas Detlef P. van Vuuren 《Climatic change》2014,123(3-4):559-569
While most long-term mitigation scenario studies build on a broad portfolio of mitigation technologies, there is quite some uncertainty about the availability and reduction potential of these technologies. This study explores the impacts of technology limitations on greenhouse gas emission reductions using the integrated model IMAGE. It shows that the required short-term emission reductions to achieve long-term radiative forcing targets strongly depend on assumptions on the availability and potential of mitigation technologies. Limited availability of mitigation technologies which are relatively important in the long run implies that lower short-term emission levels are required. For instance, limited bio-energy availability reduces the optimal 2020 emission level by more than 4 GtCO2eq in order to compensate the reduced availability of negative emissions from bioenergy and carbon capture and storage (BECCS) in the long run. On the other hand, reduced mitigation potential of options that are used in 2020 can also lead to a higher optimal level for 2020 emissions. The results also show the critical role of BECCS for achieving low radiative forcing targets in IMAGE. Without these technologies achieving these targets become much more expensive or even infeasible. 相似文献
65.
In this paper we report an analysis of the solar magnetic fluxes estimated in the period 1971–1998. We applied the wavelet
technique to find the significant periodicities of these series. We concentrate particularly in the mid-term quasi-periodicities
(1–2 years). The mid-term periodicity of 1.7 year is the dominant fluctuation for all the types of fluxes analyzed (total,
closed, open, low and high latitude open fluxes) and has a strong tendency to appear during the descending phase of solar
activity. The mid-term fluctuation of 1 year is significantly present in total and closed fluxes, but it is less important
in open fluxes. It is recognizable in the high latitude open flux, but it is absent in the low latitude open flux. Due to
the uncertainties involved in estimating the exact period of the quasi-annual peak, this component may not be different from
the previously-reported 1.3 year periodicity. The high frequency fluctuations of all the fluxes but the high latitude open
flux are in phase with the 11 years solar cycle. The high latitude flux tends to be present all the time, showing that along
the cycle both the low latitude bipolar active regions and the polar coronal holes regulate this flux. These findings rule
out the possibility of a more basic periodicity different from the 11 years cycle. 相似文献
66.
Hokanson K. J. Rostron B. J. Devito K. J. Hopkinson C. Mendoza C. A. 《Hydrogeology Journal》2022,30(1):251-264
Hydrogeology Journal - The spatial and temporal controls on variability of the relative contributions of groundwater within and between flow systems to shallow lakes in the low-relief glaciated... 相似文献
67.
J. A. Mendoza D. H. Lee L.-H. Kim I. H. Kim J.-H. Kang 《International Journal of Environmental Science and Technology》2018,15(3):581-592
This study investigated the performance of UV light active TiO2 and UV–visible light active WO3/TiO2 nanoparticles as air purifying materials that can be potentially applied to urban green infrastructures such as rain gardens and pervious pavements. Using a laboratory-scale continuous gas flow photoreactor, the removal efficiency of gaseous nitrogen oxide (NO x ) by two different photocatalytic nanoparticles coated on natural zeolites and pervious concrete blocks was evaluated. The results showed that the TiO2- and WO3/TiO2-coated zeolites are excellent photoactive materials providing enhanced air purification function (~95% removal efficiency of NO x ) under UV and UV–visible light irradiation, respectively. In contrast, both of the TiO2- and WO3/TiO2-coated pervious concrete blocks showed a measurable NO x removal (~60%) only under UV irradiation, whereas the visible light activity of the WO3/TiO2-coated concrete block was significantly reduced (~20%) mainly due to the decrease in the photocatalytic reaction sites for visible light. This study revealed the potential utility of photocatalytic nanoparticles in improving urban air quality, in the form of the surface component of various urban infrastructures. 相似文献
68.
69.
We have systematized the effects associated with climate change on urban spaces in Chile reported between 2000 and 2012. The method was based on a review of scientific articles in three databases (Scopus, Web of Knowledge and Scielo) using 32 keywords. Only 14 research papers were found related to climate change in urban spaces, most of which were case studies focused on the capital, Santiago. The main effects on urban spaces were found in four areas: (1) increase in temperature (heat islands, heat waves), (2) health problems in vulnerable populations (cardiac complications, heat stroke, and respiratory diseases), (3) increased demand for water, and (4) damage to the urban infrastructure with resulting risk to the population. In these circumstances the following measures are needed: (1) effective incorporation of the potential impacts of climate change into territorial planning instruments, (2) increased green areas to mitigate the impact of heat waves, (3) limiting of housing or public services in areas at risk, (4) encouraging the design of adaptation plans by involving the vulnerable population, and (5) implementing water conservation measures. We conclude that climate change is causing effects in urban areas that should be considered in the design and expansion of cities. 相似文献
70.
A. M. S. Richards R. J. Cohen M. Crocker E. E. Lekht E. Mendoza V. A. Samodurov 《Astrophysics and Space Science》2005,295(1-2):19-25
We have imaged H2O maser emission from the star-forming region S128 at milli-arcsec resolution using MERLIN, to complement 20 years of monitoring data from the Puschino radio telescope. The drift velocities of the masers and the velocity and location of a new maser region add depth to the model of two colliding CO clouds triggering collapse. Some H2O masers appear to originate directly from this shock front. The brightest maser appears typical of a YSO jet and remains unsaturated close to peak intensity. The distribution of maser clumps has a fractal dimension 0.4; combined with analysis of drift velocity variations this suggests that the masers trace the dissipation of supersonic turbulence. The spatial distribution of velocities shows that this is in parts more structured than the Kolmogorov cascade. 相似文献