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231.
James B. Cotner Rosa H. Sada Harvey Bootsma Thomas Johengen Joann F. Cavaletto Wayne S. Gardner 《Estuaries and Coasts》2000,23(5):611-620
We examined heterotrophic bacterial nutrient limitation at four sites in Florida Bay, U. S. in summer 1994 and winter 1995. Bacterial growth and biomass production in this system were most limited by inorganic phosphorus (P) in the eastern and southern regions of the bay. Nutrient additions stimulated productivity and biomass accumulation mostly in summer. The magnitude of growth responses (thymidine incorporation) to nutrient additions was nearly an order of magnitude less in winter than summer. Biomass-normalized alkaline phosphatase activity in the northeast and south-central region was 5–20 times greater than in the northwest and north-central regions, suggesting that P is most limiting to planktonic growth in those areas. Chlorophyll levels were higher in the northwest and north-central regions and P-uptake into particles >1 μm, primarily phytoplankton, was also higher in these regions. Consistent with these observations, others have observed that P is advected into the bay primarily in the northwestern region. Abundant seagrasses in Florida Bay may promote heterotrophic bacterial production relative to phytoplankton production by releasing dissolved organic carbon that makes bacteria more competitive for limiting quantities of inorganic phosphate, especially in the eastern bay where turbidity is low, P is most limiting, and light levels reaching the benthic plants are high. 相似文献
232.
Transitional, entraining, cloudy, and coastal boundary layers 总被引:2,自引:0,他引:2
Wayne M. Angevine 《Acta Geophysica》2008,56(1):2-20
Atmospheric boundary layers are marvelously varied and complex. Recent research has examined some of that variety. Boundary
layers over land undergo drastic changes throughout the day as the sun rises and sets, and as clouds form and dissipate. Air
is entrained at the top of the boundary layer at varying rates. As air moves over the coast, the boundary layer reacts to
changes in surface forcing. All of these changes affect pollutant transport and weather formation. In this paper, research
attempting to understand transitional, cloud-topped, and coastal boundary layers, and boundary-layer top entrainment, is reviewed. 相似文献
233.
Fisher WS Fore LS Hutchins A Quarles RL Campbell JG LoBue C Davis WS 《Marine pollution bulletin》2008,56(10):1737-1745
Colonies of reef-building stony corals at 57 stations around St. Croix, US Virgin Islands were characterized by species, size and percentage of living tissue. Taxonomic, biological and physical indicators of coral condition were derived from these measurements and assessed for their response to gradients of human disturbance—a requirement for indicators used in regulatory assessments under authority of the Clean Water Act. At the most intensely disturbed location, five of eight primary indicators were highly correlated with distance from the source of disturbance: Coral taxa richness, average colony size, the coefficient of variation of colony size, total topographic coral surface area, and live coral surface area. An additional set of exploratory indicators related to rarity, reproductive and spawning mode and taxonomic identity were also screened. The primary indicators demonstrated sufficient precision to detect levels of change that would be applicable in a regional-scale regulatory program. 相似文献
234.
Din Siti Sabariah Chew Kit Wayne Chang Yu-Kaung Show Pau Loke Phang Siew Moi Juan Joon Ching 《中国海洋湖沼学报》2019,37(3):871-880
The effect of sonication pretreatment condition on Eucheuma cottonii and Gelidium amansii seaweed towards agar extraction wae studied. Four parameters were changed during sonication to investigate the effects on agar yield and quality. These parameters include the time interval, concentration ratio, frequency, and intensity. The highest amount of agar extracted from Eucheuma cottonii species could be obtained from the time interval of 30 min, seaweed weight to solvent volume ratio of 1:20, the frequency of 35 Hz, and the sonication power intensity of 30%. For Gelidium amansii species, the best agar yield also could be obtained from the time interval of 30 min, 1:20 of seaweed weight to water volume ratio, the frequency of 35 Hz, and power intensity of 30%. From the experiment, sonication pretreatment significantly influenced the yield and properties of extracted agar. The sonication with autoclaved seaweed produced agar containing less sulfate content, which is an excellent chemical property for gel electrophoresis applications.The gel strength of sonication with autoclaving for both seaweeds, Eucheuma and Gelidium species was the highest among those by sonication with direct heating, which proved that sonication pretreatment with autoclaving could enhance the physical properties of the agar. 相似文献
235.
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237.
It have been measured the denitrification rates (DR) of sediment in Saginaw Bay, Lake Huron, by N2 production method. Triplicate samples of sediment core were collected at two GLERL long-term monitoring sites of the Bay in July and August of 1995. The DR are 48.81 -24.99 and 32.81-40.51 micromol N2 -2h-1 in the Inner and Outer regions of Saginaw Bay, respectively.The characters of DR in Saginaw Bay were studied also in this paper. The DR were influenced by the interactions between the Saginaw River as a main pollution source and the Lake Huron as a reservoir of high quality water. The impacts of zebra mussels (Dreissena Polymorpha) on denitrification in Saginaw Bay, Lake Huron, were discussed, Significant differences in NH4+ exchange fluxes were detected in the inner and outer bays. The molar ratios of N2:TIN were similar at both sampling sites. Measured DR were positively correlated to O2 consumption rates in the headspace. Additionally, a negative correlation between NH4+ and NO3- concentrations in the overlying water was found. 相似文献
238.
239.
Sean Pascoe Wendy Proctor Chris Wilcox James Innes Wayne Rochester Natalie Dowling 《Marine Policy》2009,33(5):750-758
Fisheries management is increasingly involving a wide range of stakeholders in the decision making process. However, in most fisheries, the set of management objectives are poorly defined, and the implicit importance placed on these objectives may vary considerably both between and within different stakeholder groups. This may lead to conflicts within management advisory groups where members from different stakeholder groups view potential management outcomes substantially differently, and inconsistencies in decision making when changes in stakeholder representation take place. In this paper, the institutional structure of fisheries management in Australia and the roles the different organisations play in shaping fisheries management plans are detailed. An explicit hierarchy of management objectives is developed in collaboration with key managers and policy makers. A large survey of stakeholders involved in Australian Commonwealth fisheries management was undertaken to determine stakeholder preferences relating to these objectives. The results highlight the differences in perspectives regarding the relative importance of the multiple objectives of fisheries management. While on average stakeholder preferences generally correspond with their expected preference set, the results also indicate that there is generally low coherence within stakeholder groups. 相似文献
240.
Wayne A. Dollase 《Physics and Chemistry of Minerals》1980,6(4):295-304
The relaxation patterns around isovalent substituent atoms in the NaCl, CsCl, ZnS, CaF2, Li2O, and ReO3 structure types have been calculated. Such models (1) emphasize geometric structural criteria and are thus conceptually simple, (2) are computationally straightforward though perhaps computer-time consuming for large, low symmetry cases, and (3) agree reasonably well with more complex calculations, such as energy minimization methods. On the basis of such optimum interatomic distance models, atomic displacements resulting from an isovalent substitution: (1) depend strongly on the structural connectivity (structural type) involved, (2) are decidedly greater for atoms with radius vectors parallel to the substituent's bonds and least for atoms with radius vectors oriented between such bonds, (3) decrease in magnitude approximately inversely proportional to the square of the distance to the substituent, regardless of direction, and (4) are mostly, but not strictly, radial. The simplest relationship to structural type is the dependence on the coordination of the substituent's ligands — the greater the coordination number of the atoms bonded to the substituting atom, the less compliant the structure. 相似文献