全文获取类型
收费全文 | 687篇 |
免费 | 42篇 |
国内免费 | 8篇 |
专业分类
测绘学 | 12篇 |
大气科学 | 86篇 |
地球物理 | 171篇 |
地质学 | 251篇 |
海洋学 | 58篇 |
天文学 | 116篇 |
综合类 | 5篇 |
自然地理 | 38篇 |
出版年
2024年 | 2篇 |
2023年 | 2篇 |
2022年 | 12篇 |
2021年 | 19篇 |
2020年 | 20篇 |
2019年 | 12篇 |
2018年 | 22篇 |
2017年 | 36篇 |
2016年 | 46篇 |
2015年 | 35篇 |
2014年 | 39篇 |
2013年 | 56篇 |
2012年 | 40篇 |
2011年 | 40篇 |
2010年 | 39篇 |
2009年 | 40篇 |
2008年 | 40篇 |
2007年 | 11篇 |
2006年 | 33篇 |
2005年 | 26篇 |
2004年 | 15篇 |
2003年 | 13篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 9篇 |
1997年 | 20篇 |
1996年 | 5篇 |
1995年 | 10篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1962年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有737条查询结果,搜索用时 15 毫秒
731.
Akinyemi Gabriel Omonijo Clement Olabinjo Adeofun Olusegun Oguntoke Andreas Matzarakis 《Theoretical and Applied Climatology》2013,113(1-2):205-212
The interconnection between weather and climate and the performance, well-being, and human health cannot be overemphasized. The relationship between them is of both local and global significance. Information about weather, climate, and thermal environment is very important to human health and medical practitioners. The most crucial environmental information needed by medical practitioners and for maintaining human health, performance, and well-being are thermal conditions. The study used meteorological variables: air temperature, relative humidity, wind speed, solar radiation, and RayMan model as an analytical tool to compute physiologically equivalent temperature (PET) in order to assess thermo-physiological thresholds in Ondo State. The study revealed that there are marked spatial and seasonal variations in the environmental thermal conditions in the study area. The results of physiologically equivalent temperature for different grades of thermal sensation and physiological stress on human beings indicate that about 60 % of the total study period (1998–2008) fall under physiological stress level of moderate heat stress (PET 31–36 °C). In derived savannah, 32.6 % out of the total study period was under strong heat stress. In view of this, the study concluded that Ondo State may likely be prone to heat-related ailments and that some of the death recorded in the State, in recent times, may be heat-related mortality, but this is difficult to ascertain because there is no postmortem records in Nigeria where it could be confirmed. This type of study is relevant to help government to improve health care interventions and achieve Millennium Development Goals in health sector. 相似文献
732.
RUDOLF O. WEBER PETER TALKNER INGEBORG AUER REINHARD BÖHM MARJANA GAJIĆ-ČAPKA KSENIJA ZANINOVIĆ RUDOLF BRÁZDIL PAVEL FAŠKO 《Climatic change》1997,36(3-4):327-344
Daily maximum and minimum temperatures from 29 low-lying and mountain stations of 7 countries in Central Europe were analyzed. The analysis of the annual variation of diurnal temperature range helps to distinguish unique climatic characteristics of high and low altitude stations. A comparison of the time series of extreme daily temperatures as well as mean temperature shows a good agreement between the low-lying stations and the mountain stations. Many of the pronounced warm and cold periods are present in all time series and are therefore representative for the whole region. A linear trend analysis of the station data for the period 1901–1990 (19 stations) and 1951–1990 (all 29 stations) shows spatial patterns of similar changes in maximum and minimum daily temperatures and diurnal temperature range. Mountain stations show only small changes of the diurnal temperature range over the 1901–1990 period, whereas the low-lying stations in the western part of the Alps show a significant decrease of diurnal temperature range, caused by strong increase of the minimum temperature. For the shorter period 1951–1990, the diurnal temperature range decreases at the western low-lying stations, mainly in spring, whereas it remains roughly constant at the mountain stations. The decrease of diurnal temperature range is stronger in the western part than in the eastern part of the Alps. 相似文献
733.
Judit Bartholy Rita Pongrácz Margit Pattantyús-Ábrahám 《Theoretical and Applied Climatology》2009,96(1-2):133-144
Midlatitude cyclones are analyzed on a selected region covering most of southern Europe and the western part of the Mediterranean Sea (35–50°N, 10°W–25°E). On the basis of mean sea level pressure fields of the ECMWF (European Centre for Medium-range Weather Forecast) Reanalysis Dataset (ERA-40), detailed evaluation of Mediterranean cyclones is accomplished for the period between 1957 and 2002 on a 1° horizontal resolution grid. Cyclone centers are identified and their paths are tracked with a 6-h time step (using 00 UTC, 06 UTC, 12 UTC, and 18 UTC). Decadal, annual, and seasonal statistical analysis of cyclone tracks includes the study of the genesis, frequency, and activity of the Mediterranean cyclones as well as the variability of cyclone tracks. The results suggest that the cyclone frequency in the western Mediterranean region increased in summer and autumn, and decreased in winter and spring. A special belt-shaped area is identified, which plays a special role in cyclogenesis, and also, the cyclone tracks often remain within this belt. An overall decreasing trend is detected in winter and spring in the entire Mediterranean belt, while cyclone frequency increased in autumn. The largest positive and negative trend coefficients are identified in summer. 相似文献
734.
735.
R. Damian Nance Gabriel Guti errez-Alonso J. Duncan Keppie Ulf Linnemann J. Brendan Murphy Cecilio Quesa Rob A. Strachan Nigel H. Woodcock 《地学前缘(英文版)》2012,3(2):125-135
The Rheic Ocean was one of the most important oceans of the Paleozoic Era.It lay between Laurentia and Gondwana from the Early Ordovician and closed to produce the vast Ouachita-Alleghanian -Variscan orogen during the assembly of Pangea.Rifting began in the Cambrian as a continuation of Neoproterozoic orogenic activity and the ocean opened in the Early Ordovician with the separation of several Neoproterozoic arc terranes from the continental margin of northern Gondwana along the line of a former suture.The rapid rate of ocean opening suggests it was driven by slab pull in the outboard lapetus Ocean.The ocean reached its greatest width with the closure of lapetus and the accretion of the periGondwanan arc terranes to Laurentia in the Silurian.Ocean closure began in the Devonian and continued through the Mississippian as Gondwana sutured to Laurussia to form Pangea.The ocean consequently plays a dominant role in the Appalachian-Ouachita orogeny of North America,in the basement geology of southern Europe,and in the Paleozoic sedimentary,structural and tectonothermal record from Middle America to the Middle East.Its closure brought the Paleozoic Era to an end. 相似文献
736.
Ákos Török 《Environmental Geology》2008,56(3-4):583-594
The travertine buildings of Budapest show extensive black crust formation, which is related to high concentration of atmospheric pollution and a continental climate. Laminar black crusts, framboidal black crusts and leached white surfaces are compared. Physical properties (Schmidt hammer rebound, Duroscope rebound), mineralogical composition and elemental composition are measured. Framboidal black crusts contain more than 50% of acicular gypsum. The crust surface displays idiomorphic rosette-like gypsum crystals with particulates, calcite and gypsum crystal aggregates. The sulphur isotopic composition of the black crusts pinpoints the involvement of rain and dust in crust formation. Thick framboidal black crust has the lowest strength while thin laminar black crust and white dissolved surfaces show minor decrease in surface strength compared to unaltered travertine. The crusts adhere to the travertine surface and rarely show mechanical decay forms that are typical features of porous limestone ashlars in Budapest. 相似文献
737.
F. A. Temporim Ricardo Ivan Ferreirae da Trindade Marcos Egydio-Silva Tiago Valim Angelo Eric Tohver Caroline Cibele Soares Lucas Pequeno Gouvêa Julio Cesar Mendes Silvia Regina Medeiros Antônio Carlos Pedrosa-Soares Gabriel Gomes Silva 《地学学报》2023,35(1):23-31
Featuring 3 000-km-long large and hot orogen, the Mantiqueira Province provides a rare opportunity to study the process of gravitational collapse at mid to deep crustal levels. Distinct but contemporary (~500 Ma) post-collisional intrusions show structures and anisotropy of magnetic susceptibility (AMS) fabrics related to their emplacements, recording different flow patterns. In southern deep-seated intrusions, ellipsoidal-shaped roots with gabbroic-to-hybrid cores surrounded by granitic rocks show concentric patterns of AMS fabrics that cut across the NE-trending regional foliation. In contrast, northern intrusions, exposed as the upper sections of batholith-size bodies of coarse-grained granite emplaced at the shallow to mid-crust, show general NS-trending magnetic fabrics roughly parallel to strike of the orogen and the regional foliation of host rocks. These contrasting magnetic patterns from shallow to deeper crust suggest vertical magma migration from the overthickened orogenic core to be emplaced across its thinner stretched flanks during the gravitational collapse of the orogenic edifice. 相似文献