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71.
A hydrogeochemical survey was conducted on Pico Island (Azores archipelago) in order to evaluate the groundwater chemistry
patterns and the main mineralization processes. Samples were from cold waters and corresponded mainly to sodium chloride type.
Conductivity measurements were ∼82–9790 μS/cm and suggest the existence of highly mineralized waters. In fact, 18% had a conductivity
>5130 μS/cm and the total dissolved solid (TDS) value for two of the wells was from the brackish water range. The changes
in groundwater composition are because of two main processes: (1) silicate mineral dissolution, especially in a few springs
located at high altitude and (2) water salinization in the coastal area, as a result of saltwater intrusion and sea-salt spraying.
The salinization process corresponds to a binary mixing system, as suggested by the chloride and δ18O data, and explains the sharp concentration increase in major and minor species detected in several wells.
Received: 23 July 1999 · Accepted: 8 December 1999 相似文献
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E. A. Laycock K. Spence D. P. Jefferson S. Hetherington B. Martin C. Wood 《Environmental Geology》2008,56(3-4):521-528
This research aimed to specify an optimum replacement stone for Truro Cathedral. A variety of petrographically and visually similar material to the original Bath stone was initially selected. The stones were subjected to three different durability tests; Sodium sulphate crystallisation and large scale testing with both accelerated and climatic freeze-thaw cyclic loading. The most suitable stone was determined as the one with the best performance characteristics overall. 相似文献
75.
The paper suggests a modeling approach for assessing economic and social impacts of changes in urban forms and commuting patterns that extends a multi-regional input–output framework by incorporating a set of commuting-related consequences. The Lisbon Metropolitan Area case with an urban re-centralization scenario is used as an example to illustrate the relevance of this modeling approach for analyzing commuting-related changes in regional income distribution on the one side and in household consumption structures on the other. 相似文献
76.
Bijeesh?Kozhikkodan?VeettilEmail author Shanshan?Wang Ulisses?Franz?Bremer Sergio?Florêncio?de?Souza Jefferson?Cardia?Sim?es 《Theoretical and Applied Climatology》2017,127(1-2):213-227
TL-moments approach has been used in an analysis to identify the best-fitting distributions to represent the annual series of maximum streamflow data over seven stations in Johor, Malaysia. The TL-moments with different trimming values are used to estimate the parameter of the selected distributions namely: Three-parameter lognormal (LN3) and Pearson Type III (P3) distribution. The main objective of this study is to derive the TL-moments (t 1,0), t 1?=?1,2,3,4 methods for LN3 and P3 distributions. The performance of TL-moments (t 1,0), t 1?=?1,2,3,4 was compared with L-moments through Monte Carlo simulation and streamflow data over a station in Johor, Malaysia. The absolute error is used to test the influence of TL-moments methods on estimated probability distribution functions. From the cases in this study, the results show that TL-moments with four trimmed smallest values from the conceptual sample (TL-moments [4, 0]) of LN3 distribution was the most appropriate in most of the stations of the annual maximum streamflow series in Johor, Malaysia. 相似文献
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Bijeesh Kozhikkodan Veettil Nilceia Bianchini Ulisses Franz Bremer Éder Leandro Bayer Maier Jefferson Cardia Simões 《国际地球制图》2016,31(1):109-119
This study discusses the formation and variations of supraglacial lakes on the Baltoro glacier system in the central Karakoram Himalaya during the last four decades. We mapped supraglacial lakes on the Baltoro Glacier from 1978 to 2014 using Landsat MSS, TM, ETM + and LCDM images. Most of the glacial lakes were formed or expanded during the late 1970s–2008. After 2008, the total number and the area of glacial lakes were found to be lesser compared to previous years. We tried to find any teleconnections exists between the glacial lake changes in this region and the pacific decadal oscillation (PDO), which entered its prolonged warm regime in the late 1970s and again to its cold regime in 2008, based on observational investigation. The decrease in the number and area of the supraglacial lakes after 2008 is hypothesised to be linked with the recent cold phase of PDO. 相似文献
79.
Effects of oil on phytoplankton metabolism in natural and experimental estuarine ponds 总被引:1,自引:0,他引:1
Armando A. De La Cruz 《Marine environmental research》1982,7(4):257-263
A low level oil spill was simulated in small shallow natural estuarine marsh ponds in Ocean Springs and in experimental impoundments near St. Louis Bay, Mississippi. In the natural tidal pond in situ light and dark BOD bottle experiments on the phytoplankton community revealed a 44 to 65 % reduction in primary production and a 30 to 50 % reduction in respiration 2 weeks after spillage of 1·45 mg Empire Mix crude oil per litre of water. Two months after the spill, primary productivity and respiration in the oiled pond were only 17% and 7% lower, respectively than in the control pond. In the experimental impoundments at a concentration of 0·2 mg Arabian, Empire Mix and Nigerian oil per litre of water, in situ radiocarbon uptake by phytoplankton was lower—but not significantly lower—than that of the control impoundment. One to two months later, primary productivity was significantly higher in the Nigerian and Arabian oil ponds than control and Empire Mix ponds. The changes in plankton metabolism in both natural ponds and impoundments were evaluated on the basis of data simultaneously obtained from adjoining control ponds. 相似文献
80.
Abstract. The diet of the copepod Anomalocera ornata was examined by comparing contents of fecal pellets produced on natural diets with assemblages of available phytoplankton. Samples were collected in continental shelf and slope waters of the northern Gulf of Mexico. A wide size and taxonomic array of phytoplankters was ingested, and remains of phytoplankton taxa in fecal pellets reflected the composition of phytoplankton assemblages in the water. Absence of crustacean remains in fecal pellets suggests that A. ornata feeds primarily as an opportunistic grazer. 相似文献