全文获取类型
收费全文 | 2527篇 |
免费 | 94篇 |
国内免费 | 27篇 |
专业分类
测绘学 | 53篇 |
大气科学 | 198篇 |
地球物理 | 1113篇 |
地质学 | 699篇 |
海洋学 | 97篇 |
天文学 | 430篇 |
综合类 | 7篇 |
自然地理 | 51篇 |
出版年
2021年 | 32篇 |
2020年 | 34篇 |
2019年 | 26篇 |
2018年 | 76篇 |
2017年 | 86篇 |
2016年 | 123篇 |
2015年 | 92篇 |
2014年 | 118篇 |
2013年 | 128篇 |
2012年 | 77篇 |
2011年 | 97篇 |
2010年 | 106篇 |
2009年 | 101篇 |
2008年 | 86篇 |
2007年 | 75篇 |
2006年 | 46篇 |
2005年 | 34篇 |
2004年 | 37篇 |
2003年 | 43篇 |
2002年 | 53篇 |
2001年 | 32篇 |
2000年 | 38篇 |
1999年 | 27篇 |
1998年 | 43篇 |
1997年 | 25篇 |
1996年 | 47篇 |
1995年 | 28篇 |
1994年 | 35篇 |
1993年 | 43篇 |
1992年 | 36篇 |
1991年 | 32篇 |
1990年 | 39篇 |
1989年 | 28篇 |
1988年 | 34篇 |
1987年 | 27篇 |
1986年 | 37篇 |
1985年 | 22篇 |
1984年 | 36篇 |
1983年 | 33篇 |
1982年 | 35篇 |
1981年 | 26篇 |
1980年 | 24篇 |
1979年 | 39篇 |
1978年 | 31篇 |
1977年 | 26篇 |
1975年 | 22篇 |
1974年 | 26篇 |
1973年 | 26篇 |
1972年 | 28篇 |
1971年 | 29篇 |
排序方式: 共有2648条查询结果,搜索用时 31 毫秒
121.
Anders Elverhi Willy Fjeldskaar Anders Solheim Mona Nyland-Berg Lars Russwurm 《Quaternary Science Reviews》1993,12(10)
On the basis of geomorphological and sedimentological data, we believe that the entire Barents Sea was covered by grounded ice during the last glacial maximum. 14C dates on shells embedded in tills suggest marine conditions in the Barents Sea as late as 22 ka BP; and models of the deglaciation history based on uplift data from the northern Norwegian coast suggest that significant parts of the Barents Sea Ice Sheet calved off as early as 15 ka BP. The growth of the ice sheet is related to glacioeustatic fall and the exposure of shallow banks in the central Barents Sea, where ice caps may develop and expand to finally coalesce with the expanding ice masses from Svalbard and Fennoscandia.The outlined model for growth and decay of the Barents Sea Ice Sheet suggests a system which developed and existed under periods of maximum climatic deterioration, and where its growth and decay were strongly related to the fall and rise of sea level. 相似文献
122.
Jan Laštovička 《Studia Geophysica et Geodaetica》1994,38(2):206-212
Summary The nighttime LF radio wave absorption in the lower ionosphere measured at two frequencies in central Europe over 1963–1985
is used to infer planetary wave activity and its long-term trend in the upper middle atmosphere (∼90–100 km). The observed
positive trend is roughly consistent with results based on daytime absorption. Nighttime results are less pronounced and less
statistically significant probably due to perturbing effects of geomagnetic activity. The observed trends, which are probably
of anthropogenic origin, are together with the daytime results [3,4] the first evidence of long-term trends in planetary wave
activity in the upper middle atmosphere. 相似文献
123.
The results of X-ray induced photoelectron spectroscopy (XPS) experiments on several phases of the ternary system Tl-Sb-S are reported. The binding energies of the inner S, Sb and Tl electrons increase with increasing quantities of Sb and decreasing amounts of Tl in these compounds. This is explained by the influences of the proportions of the bonded metals on the effective electron affinity of S. The higher proportions of the more electronegative element bonded to S cause the increase of its effective electron affinity. The results for Tl2S (carlinite), Tl3SbS3, TlSbS2 (weissbergite), TlAsS2 (lorandite) and Sb2S3 (antimonite) can be interpreted in this way. The results for Tl4S3 suggest a predominantly covalent character of bonding for both Tl(III) and Tl(I), which are present in this sulfide. From comparison with Tl3SbS4 it could be supposed that Tl(III)-S bond has a more covalent character than Sb(V)-S bond. The results for Tl3SbS4 are in agreement with crystal structure data and the results of Moessbauer spectroscopy. For AsS (realgar) the binding energies of the inner electrons of As and S significantly increase, showing that the electrons in molecular orbitals are less strongly bonded to individual atoms, as compared to pure elements. The results for the amorphous TlSb5S8 (corresponding in composition to parapierrotite) suggest that in amorphous compound the Tl-S bonding is stronger and the coordination of Tl more regular than in a crystalline one. 相似文献
124.
125.
Modelling magnetization processes in single-and multi-domain rock samples using the preisach diagram
Summary The paper presents the results of identifying a model of the Preisach type for haematite grains of the single-domain as well as multi-domain size. Due to the phenomenological conception of the model, the relations between the parameters of the model and actual parameters are very complex, however, impressive accuracy and stability of the modified model indicate the need to resume studies of this problem. The model parameters also confirm the adequate properties of the vibrating-sample magnetometr (VSM) used and developed in our laboratories. 相似文献
126.
Unkašević Miroslava 《Theoretical and Applied Climatology》1991,44(3-4):223-228
Summary For practical applications both the parent distribution of rainfall intensities and the distribution of their annual maxima are of interest. The relationship between these two distributions cannot be obtained from classical extreme value theory because of seasonal variation and serial correlation in the data. Mathematical results for the distribution of maxima in m-dependent sequences are presented to illustrate the effect of local dependence on the extreme value distribution. The average number of exceedances in a cluster is an important parameter in the relationship between the parent and the extreme value distribution. For 5-min rainfall data from Belgrade, quantiles of the annual maxima are overestimated by about 10 mm h–1 if the effect of serial correlation is ignored. This bias can easily be removed by taking the local clustering of large rainfall intensities in a rainy spell into account.With 4 Figures 相似文献
127.
Summary On the basis of the 1966–73 data, the effect of the difference between pro- and anti-sectors of the IMF is found to be negligible in the winter midlatitude (Central Europe) ionosphere contrary to the dominant effect of this difference in the high-latitude ionosphere found earlier.
a ¶rt;a a 1966–73. u¶rt;m u m amu ¶rt; pro- u anti- mau . na a u ¶rt;um (¶rt; na) u, , a naa a, naum um u.相似文献
128.
129.
130.
Summary The hypothesis of an expanding Earth is discussed on the basis of lunar laser ranging It is provcd that the given data do not indicate a secular increase in the principal moment of the Earth's inertia which would have to occur if the Earth were really expanding.
¶rt;amunma au u mu u ammuu a¶rt;u u ¶rt;a n a auu . aam, m n mu ¶rt;a m umamu amaua ma uuu u, m ¶rt; nmmam auu, u n¶rt; u m.相似文献