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121.
Tomas?O.?H??kEmail author Edward?S.?Rutherford Shannon?J.?Brines Doran?M.?Mason David?J.?Schwab Michael?J.?McCormick Timothy?J.?DeSorcie 《Estuaries and Coasts》2003,26(1):21-29
The identification and protection of essential habitats for early life stages of fishes are necessary to sustain fish stocks.
Essential fish habitat for early life stages may be defined as areas where fish densities, growth, survival, or production
rates are relatively high. To identify critical habitats for young-of-year (YOY) alewives (Alosa pseud oharengus) in Lake Michigan, we integrated bioenergetics models with GIS (Geographic Information Systems) to generate spatially explicit
estimates of potential population production (an index of habitat quality). These estimates were based upon YOY alewife bioenergetic
growth rate potential and their salmonine predators’ consumptive demand. We compared estimates of potential population production
to YOY alewife yield (an index of habitat importance). Our analysis suggested that during 1994–1995, YOY alewife habitat quality
and yield varied widely throughout Lake Michigan. Spatial patterns of alewife yield were not significantly correlated to habitat
quality. Various mechanisms (e.g., predator migrations, lake circulation patterns, alternative strategies) may preclude YOY
alewives from concentrating in areas of high habitat quality in Lake Michigan. 相似文献
122.
123.
Sorption and Intraparticle Diffusion of Fluorescent Dyes with Consolidated Aquifer Media 总被引:2,自引:0,他引:2
David A. Sabatini 《Ground water》2000,38(5):651-656
124.
125.
Structural similarities between dry diopside melt and superhydrous albite melt (X
w
>0.5) — both lack three-dimensional silicate units — suggest that thermodynamic relations may be similar. A model based on that assumption successfully predicts diopside melting relations and H2O solubilities. For the model, the three partial differential equations describing solution of H2O in albite melt for X
w
>0.5 have been integrated for diopside melt from X
w
=0 to X
w at least as large as 0.76, with two exceptions: an alternative partial differential equation for Henrian solution of H2O in dilute melts was applied for X
w
<0.20, and an alternative differential equation for the pressure dependence of a
w
at pressures below 2 kbar was developed. The latter alternative equation yields relatively small ¯Vw's at low pressures rather than the large ¯Vw's calculated from the equation from the albite system. Available experimental solubility data are not precise enough to offer a choice between the small-¯Vw and large-¯Vw equations. Integration of all the partial differential equations was constrained solely by the P and T of a single experimentally-determined point on the H2O-saturated solidus.Solubilities calculated by a Henrian-analogue solution model (a
di=X
di
2
) from the experimental H2O saturated solidus lie outside experimental solubility constraints for dilute melts. On the other hand, a Henrian model (a
di=Xdi) successfully predicts solubilities in dilute melts. The formulation of the Henrian model and magnitudes of model molar entropies of solution are consistent with the hypothesis that H2O dissolves in diopside melt as an essentially undissociated species with little ordering on melt structural sites. That species could in turn be consistently, if not uniquely, interpreted to be molecular H2O or a hydroxylation (OH–) complex formed from nonbridging oxygens. 相似文献
126.
The in situ uptake of mercury in tissues of Mytilus californianus was studied by exposing control specimens to waters at four depths near a submarine wastewater discharge for a period of 24 weeks. The response patterns observed for digestive gland, adductor muscle and gonadal tissues were strikingly different. Digestive gland concentrations increased rapidly to the heightened levels found for indigenous specimens. On the other hand, changes in the mercury content of adductor muscle were not statistically significant, and gonadal tissues generally exhibited a low rate of increase. No correlation with depth was observed. 相似文献
127.
Experimental silicate mineral/melt partition coefficients for beryllium and the crustal Be cycle from migmatite to pegmatite 总被引:1,自引:0,他引:1
Partition coefficients (DBemineral/melt) for beryllium between hydrous granitic melt and alkali feldspars, plagioclase feldspars, quartz, dark mica, and white mica were determined by experiment at 200 MPa H2O as a function of temperature (650-900°C), activity of Be in melt (trace levels to beryl saturation), bulk composition, and thermal run direction. At trace levels, Be is compatible in plagioclase of An31 (1.84 at 700°C) and muscovite (1.35 at 700°C) but incompatible in biotite (0.39-0.54 from 650-800°C), alkali feldspar (0.38-0.19 from 680-850°C), quartz (0.24 at 800°C), and albite (0.10 at 750°C). The partition coefficients are different at saturation of the melt in beryl: lower in the case of plagioclase of An31 (0.89 at 700°C), muscovite (0.87 at 700°C), biotite (0.18-0.08 from 675-800°C), alkali feldspar (0.18-0.14 from 680-700°C), and quartz (0.17-0.08 from 750-800°C), but higher in the case of albite (0.37 at 750°C).With other data sources, these new partition coefficients were utilized to track, first, the distribution of Be between aluminous quartzofeldspathic source rocks and their anatectic melts, and second, the dispersion or concentration of Be in melt through igneous crystal fractionation of different magma types (e.g., S-type, I-type) up to beryl-saturated granitic pegmatites and, finally, into their hydrothermal aureoles. Among the rock-forming minerals, cordierite, calcic oligoclase, and muscovite (in this order) control the fate of Be because of the compatibility of Be in these phases. In general, beryl-bearing pegmatites can arise only after extended crystal fractionation of large magma batches (to F, fraction of melt remaining, ≤0.05); granitic magmas that originate from cordierite-bearing protoliths or that contain large modal quantities of calcic oligoclase will not achieve beryl saturation at any point in their evolution. 相似文献
128.
129.
Here we have examined interactions of gold nanoparticles differing in primary particle size and coating with the green algae Chlamydomonas reinhardtii as function of the colloidal stability of the particles in the experimental media used for toxicity studies. Interactions of dissolved Au3+ ions with algae were also examined. Included endpoints were photosynthetic yield and algal growth. Morphological and structural effects were examined microscopically and by flow cytometry. The results indicate no significant toxicity of gold nanoparticles to C. reinhardtii. Analysis of published data suggests toxicity of gold nanoparticles on algal growth to relate rather to particular coatings than to the gold core. 相似文献
130.
David A. Newman 《Geotechnical and Geological Engineering》1989,7(2):163-170
Summary An indication of the complete stress-strain behaviour of coal was obtained through instrumenting a headgate yield pillar and monitoring the changes in vertical and horizontal pillar stress, pillar strain, and roof-floor convergence as a function of time and distance from the moving longwall face. A semiautomated monitoring program was conducted over a 5 month period as the longwall face advanced toward and eventually passed the instrumented pillar. The development of a confined core and yield zone within the pillar was confirmed by the vertical and horizontal stress changes. Thein situ pre-failure (208 to 661 MPa) and post-failure moduli (55 to 208 MPa) of the coal were determined from the change in pillar stress versus pillar strain. Thein situ moduli are an order of magnitude lower than the 3450 MPa, commonly assumed for coal. 相似文献