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181.
为了给罗布泊地区铁路建设提供可靠、准确详实的设计依据,基于勘测与试验结果,分析罗布泊地区工程地质与水文地质条件.针对罗布泊地区地表岩盐中Na2SO4和NaCl含量较高的地质特点,分析罗布泊岩盐作为路基填料的工程与力学特性,提出路基施工建议及一种方便、实用、适合施工现场试验条件不足时,岩盐破碎岩土体含盐量判别和检测计算方法. 相似文献
182.
Harilal B. Menon Nutan P. SangekarAneesh A. Lotliker P. Vethamony 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(4):545-552
The spatial and temporal distribution of absorption of chromophoric dissolved organic matter at 440 nm (aCDOM (440)) in the Mandovi and Zuari estuaries situated along the west coast of India, has been analysed. The study was carried out using remotely sensed data, obtained from the Ocean Colour Monitor (OCM) on board the Indian Remote Sensing satellite — P4, together with in situ data during the period January to December 2005. Satellite retrieval of CDOM absorption was carried out by applying an algorithm developed for the site. A good correlation (R=0.98) was obtained between satellite derived CDOM and in situ data. Time series analysis revealed that spatial distribution of CDOM has a direct link with the seasonal hydrodynamics of the estuaries. The effect of remnant fresh water on CDOM distribution could be analysed by delineating a plume in the offshore region of the Zuari estuary. Though fresh water flux from terrestrial input plays a major role in the distribution of CDOM throughout the Mandovi estuary, its role in the Zuari estuary is significant up to the middle zone. Other processes responsible for feeding CDOM in both the estuaries are coastal advection, in situ production and resuspension of bottom settled sediments. The highest value of aCDOM(440) was observed in the middle zone of the Mandovi estuary during the post-monsoon season. The relation between aCDOM(440) and S (spectral slope coefficient of CDOM) could differentiate CDOM introduced in to estuaries through multiple sources. The algorithm developed for the Mandovi estuary is S=0.003 [aCDOM(440)−0.7091] while for the Zuari estuary, S=0.0031 [aCDOM(440)−0.777], respectively. 相似文献
183.
盐度对中国鲎(Tachypleus tridentatus)胚胎发育的影响 总被引:1,自引:0,他引:1
用雌雄中国鲎进行人工授精育苗,研究盐度对其胚胎发育的影响,并用未授精的卵作对照,观察其授精后 2~3 d 出现的分裂纹是否可作为受精的标志。结果表明,中国鲎人工授精育苗的可行盐度为16~40,适宜盐度为16~33。实验中,受精率在可行盐度范围内均达85% 以上,但孵化率却较低,授精后所能表现的分裂纹可作为其已受精的标志。卵的成熟度对人工授精后的卵的发育有较大的影响。 相似文献
184.
莫非 《广东海洋大学学报》1993,(2)
探索多元多项式回归在水产养殖研究中的应用,具体分析温度和盐度双因子结合对缢蛏浮游幼虫生长速度的影响,并说明了多元多项式回归分析在水产养殖研究中的优越性。 相似文献
185.
Groundwater-dependent ecology of the shoreline of the subtropical Lake St Lucia estuary 总被引:1,自引:0,他引:1
Ricky Taylor Bruce Kelbe Sylvi Haldorsen Greg A. Botha Bente Wejden Lars Været Marianne B. Simonsen 《Environmental Geology》2006,49(4):586-600
The ecology of the St Lucia estuary in South Africa is of unique international importance. During droughts the estuary experiences
high salinities, with values above that of seawater. Ion-poor groundwater flowing into the estuary from prominent sand aquifers
along its eastern shoreline forms low-salinity habitats for salt-sensitive biota. During droughts, plants and animals can
take refuge in the groundwater discharge zone until the condition in the estuary regains tolerable salinity. Simulations of
the groundwater discharge indicate that the flow can persist during droughts over at least a decade, and be of great important
for the resilience of the estuary. Anthropogenic activities have reduced the river inflow and made the St Lucia estuary more
sensitive to droughts. The groundwater has thereby become increasingly important for the estuary’s ecology. Protection of
the groundwater discharge along the shoreline itself and actions to increase the groundwater recharge are therefore important
management tasks. 相似文献
186.
Nguyen Cao Don Hiroyuki Araki Hiroyuki Yamanishi Kenichi Koga 《Environmental Geology》2005,47(3):361-374
In coastal lowland plains, increased water demand on a limited water resource has resulted in declining groundwater levels, land subsidence and saltwater encroachment. In southwestern Kyushu, Japan, a sinking of the land surface due to over pumping of groundwater has long been recognized as a problem in the Shiroishi lowland plain. In this paper, an integrated model was established for the Shiroishi site using the modular finite difference groundwater flow model, MODFLOW, by McDonald and Harbaugh (1988) and the modular three-dimensional finite difference groundwater solute transport model, MT3D, by Zheng (1990) to simulate groundwater flow hydraulics, land subsidence, and solute transport in the alluvial lowland plain. Firstly, problems associated with these groundwater resources were discussed and then the established model was applied. The simulated results show that subsidence rapidly occurs throughout the area with the central prone in the center part of the plain. Moreover, seawater intrusion would be expected along the coast if the current rates of groundwater exploitation continue. Sensitivity analysis indicates that certain hydrogeologic parameters such as an inelastic storage coefficient of soil layers significantly contribute effects to both the rate and magnitude of consolidation. Monitoring the present salinization process is useful in determining possible threats to fresh groundwater supplies in the near future. In addition, the integrated numerical model is capable of simulating the regional trend of potentiometric levels, land subsidence and salt concentration. The study also suggests that during years of reduced surface-water availability, reduction of demand, increase in irrigation efficiency and the utilization of water exported from nearby basins are thought to be necessary for future development of the region to alleviate the effects due to pumping. 相似文献
187.
L. Djabri A. Rouabhia A. Hani Ch. Lamouroux A. Pulido-Bosch 《Environmental Geology》2008,54(3):565-573
The studied area is in the Algerian Northeast. A number of interacting factors at the site are able to modify salinity. The
main influences are: (1) The lithology, (2) Fedzara Lake, (3) marine waters, and (4) a prolonged drought. (1) The lithology
is very clearly delineated by the outcrop of metamorphic formations (gneiss, marbles, micaschists, and quartzites) and sedimentary
formations (limestones, clay, sandstones, and sands). All these formations can influence the chemical composition of waters.
(2) Fedzara Lake evacuates its salted waters via the Wadi Meboudja, which connects with the Wadi Seybouse and the phreatic
surface. These lake waters might induce changes in salinity. (3) The marine waters represent the third source of salinity
change. Over-pumping of water from wells and drillings can cause an imbalance to the fresh–salted water interface. (4) The
effects of a local prolonged drought of more than 10 years may increase water salinity. Over-pumping to augment water supply
generates a fall in water levels and the drier atmosphere increases evapotranspiration. Both may contribute to increased salinity.
Results of water analysis were used to observe the evolution of these various factors. 相似文献
188.
Aleksandra Šajnović Ksenija Stojanović Branimir Jovančićević Anatoly Golovko 《Environmental Geology》2009,56(8):1629-1641
Sediments from the Valjevo-Mionica Basin of Neogene age were investigated in this study using different geochemical methods.
The results of the inorganic part analyses suggest that during genesis of the sediments, the contents of Na2O, B and As changed the most, which indicates that genesis of the investigated sediments was followed by climate changes and
volcanic activity. The quantity of other macro- and microelements did not vary significantly. Investigations of the organic
substance showed that it is native organic matter, which has been preserved to a significant extent, formed predominantly
of algal precursor organisms, which provided good quality, deposited under reducing conditions and that it is at a low maturity
level. As it has been established that genesis of the investigated sediments was mostly affected by an arid climate with more
intensive salinity, the aim of this study, was also to identify the processes which were the most affected by the change in
salinity, as well as biomarkers which are the most sensitive to this change. The results led to the conclusion that the salinity
increase in the depositional environment had a primary effect on the preservation of the organic substance and the formation
of the mineral searlesite. In addition, it was noticed that besides the Sq/nC26 ratio, the parameters nC17/nC27, CPI and Ph/nC18, are also significantly sensitive to salinity change in a depositional environment in case of immature organic substance
deposited under reducing conditions. 相似文献
189.
Salah Harrab Beya Mannai-Tayech Mohsen Rabhi Fouad Zargouni 《Comptes Rendus Geoscience》2013,345(5-6):251-261
The Messinian sediments of northeastern Tunisia were deposited under an active tectonic setting. They are organized in sequences indicating a transitional deposit from margin – littoral to lacustrine – continental facies. These series unconformably overlie the Serravallian–Tortonian silty clays packages, and are overlain by the transgressive Early Pliocene marl (Zanclean). The presence of evaporitic strata points out to the Messinian Salinity Crisis described in the peripheral basins of the western Mediterranean. The Messinian sedimentation was found to have been closely controlled by transtensive tectonics and differential subsidence at a large spatio-temporal scale. It is organized in sequences typical of a depositional environment controlled by eustatism, tectonic and maybe by climate changes. Despite the existence of some local specific sedimentological characteristics, our results corroborate previous findings that pointed out to the Messinian times as a singular period all around the Mediterranean Basin. Field and subsurface seismic profile data helped reconstructing either the sedimentary or tectonic unconformities existing between the studied Messinian series and older Neogene successions. 相似文献
190.
The relationship between Total Dissolved Ions (TDI) and conductivity is established in around 34000 samples collected from
rivers, streams and dams in Queensland since the 1960s. These data are extremely variable in content, reliability and periodicity
of sampling. The data were sorted into useable modules, and their statistical distribution was examined. The median ratios
of TDI/Conductivity obtained for different salinity ranges were between 0.59 and 0.72, with normal variability ranging from
below 0.35 to greater than 1.00, particularly at lower salinities. The data set used has sufficient sample numbers and areal
distribution per increment to give reasonable reliability within the conductivity range of 50–1000 μScm–1. A table has been developed that enables selection of conversion factors from conductivity to salinity (as TDI) which could
be used to predict TDI from future conductivity measurements from the same surface water population.
Received: 30 October 1998 · Accepted: 17 May 1999 相似文献