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191.
2 0 0 2年 7~ 8月 ,对雷州半岛的高桥、特呈岛、北潭、太平、附城、海角和和安 7个红树林集中海区作业的渔具渔法进行调查 ,发现在红树林海区作业的渔具有六大类 :陷阱类、刺网类、敷网类、笼壶类、掩罩类和拖网类。其中陷阱类的插笼网和笼壶类的虾笼是主要的作业渔具。鱼笼、蟹笼和百袋网是红树林区作业的特色渔。 相似文献
192.
EFFECTS OF FISH OIL, DHA OIL AND LECITHIN IN MICROPARTICULATE DIETS ON STRESS TOLERANCE OF LARVAL GILTHEAD SEABREAM (SPARUS AURATA) 总被引:3,自引:0,他引:3
INTRODUCTIONStudyonmarinefishlarvaenutritionisthemostadvancedintheresearchdomainoffishnutri tion .Itwasfoundinrecentyearsthatn 3highlyunsaturatedfattyacids (n 3HUFA)areessentialfattyacidsformarinelarvalfish ,andthatdocosahexaenoicacid (DHA ,2 2 :6n 3)andeicosape… 相似文献
193.
Maarten Blaauw Barbara Wohlfarth J. Andrés Christen Linda Ampel Daniel Veres Konrad A. Hughen Frank Preusser Anders Svensson 《第四纪科学杂志》2010,25(3):387-394
Several large abrupt climate fluctuations during the last glacial have been recorded in Greenland ice cores and archives from other regions. Often these Dansgaard–Oeschger events are assumed to have been synchronous over wide areas, and then used as tie‐points to link chronologies between the proxy archives. However, it has not yet been tested independently whether or not these events were indeed synchronous over large areas. Here, we compare Dansgaard–Oeschger‐type events in a well‐dated record from southeastern France with those in Greenland ice cores. Instead of assuming simultaneous climate events between both archives, we keep their age models independent. Even these well‐dated archives possess large chronological uncertainties that prevent us from inferring synchronous climate events at decadal to multi‐centennial time scales. If possible, comparisons between proxy archives should be based on independent, non‐tuned time‐scales. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
194.
Social learning is often treated as an intervention, a designed process facilitated or even initiated by a third party. We investigated how a social learning process emerged spontaneously from inside Kristianstad, one of the most flood-prone municipalities in Sweden. Twenty key persons were interviewed over 8 years, many of them several times, to assess the process. A small action oriented group of technical professionals perceived the flood risk and were key drivers providing strategic innovative capacity. We identified the process attributes that fostered the learning, the knowledge generated and other learning outcomes adapting a model by Schusler et al. (2003). Despite some elements of double loop learning, this process was not able to change the prevailing stationary principle/paradigm, feeling safe behind the embankments and continuing building on low lying land. We argue that building resilience and adaptive capacity would require a mind shift to a paradigm of flood proofing/living with floods and preparing for the unexpected, acknowledging that water cannot be controlled at a certain level. We conclude that knowledge development is inhibited by the Swedish decentralisation approach and we call for a multilevel learning strategy including learning from international experience and emphasising more active coordination at the national level. 相似文献
195.
The dissipation test evaluation method presented here employs: (i) a point-symmetric, linear, coupled consolidation model with a new boundary condition and a new time factor, (ii) an automatic and mathematically precise, non-linear, inverse problem solver which includes some reliability testing methods and a kind of regularization technique, and (iii) a method to identify the initial condition.The evaluation method is equally applicable to pore water pressure data displaying monotonic or non-monotonic time variation, with the only difference that the initial condition is identified differently during the inverse problem solution.The necessary testing time is very short provided that the pore water pressure is measured well above the tip. This is attributed to the ability of the one-dimensional, linear consolidation model to account for the geometry and the unloading effects that occur when steady penetration of the static cone penetrometer ceases. 相似文献
196.
197.
安徽东源钨矿含矿斑岩中的锆石SHRIMP U-Pb年龄及其地质意义 总被引:11,自引:0,他引:11
东源钨矿是皖南地区新发现的大型白钨矿矿床,是该地区目前为止发现的规模最大的钨矿床。东源大型白钨矿的发现实现了皖南地区地质找矿的新突破,为该地区的矿床勘查工作指出了新方向。本文对东源钨矿的地质特征进行了初步的总结和分析,并运用锆石SHRIMP U-Pb法测定了含矿岩体的成岩时间,分析了矿床形成的区域构造背景和控矿因素并初步探讨了矿床成因。研究结果表明,与东源斑岩型钨矿化有关的花岗斑岩的成岩时代为148.6±1.8Ma,为晚侏罗世岩浆侵入活动晚期的产物,并认为燕山晚期的钨多金属成矿作用有可能从华南扩展到长江中下游地区。 相似文献
198.
We present results of a technique for examining the scale-dependence of the gradient Richardson number, Ri, in the nighttime residual layer. The technique makes use of a series of high-resolution, in situ, vertical profiles of wind
speed and potential temperature obtained during CASES-99 in south-eastern Kansas, U.S.A. in October 1999. These profiles extended
from the surface, through the nighttime stable boundary layer, and well into the residual layer. Analyses of the vertical
gradients of both wind speed, potential temperature and turbulence profiles over a wide range of vertical scale sizes are
used to estimate profiles of the local Ri and turbulence structure as a function of scale size. The utility of the technique lies both with the extensive height range
of the residual layer as well as with the fact that the sub-metre resolution of the raw profiles enables a metre-by-metre
‘sliding’ average of the scale-dependent Richardson number values over hundreds of metres vertically. The results presented
here show that small-scale turbulence is a ubiquitous and omnipresent feature of the residual layer, and that the region is
dynamic and highly variable, exhibiting persistent turbulent structure on vertical scales of a few tens of metres or less.
Furthermore, these scales are comparable to the scales over which the Ri is less than or equal to the critical value of Ri
c of 0.25, although turbulence is also shown to exist in regions with significantly larger Ri values, an observation at least consistent with the concept of hysteresis in turbulence generation and maintenance. Insofar
as the important scale sizes are comparable to or smaller than the resolution of current models, it follows that, in order
to resolve the observed details of small Ri values and the concomitant turbulence generation, future models need to be capable of significantly higher resolutions. 相似文献
199.
Lars Åke Svensson 《Solar physics》1971,18(2):232-243
The level intervals in the ground configurations 3s
23p
k(k = 2, 3, 4) have been studied through the isoelectronic sequences up to Ni. Semiempirical expressions for the parameters F
2(pp) and
p, are derived from observed data and the intervals are recalculated from interpolated or extrapolated values of the parameters. As a result, predicted wavelengths of magnetic-dipole transitions within the configurations are obtained with an estimated uncertainty of one or two Å. 相似文献
200.