首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   515篇
  免费   29篇
  国内免费   2篇
测绘学   13篇
大气科学   91篇
地球物理   108篇
地质学   194篇
海洋学   28篇
天文学   95篇
综合类   2篇
自然地理   15篇
  2022年   3篇
  2021年   4篇
  2020年   7篇
  2019年   5篇
  2018年   24篇
  2017年   26篇
  2016年   53篇
  2015年   29篇
  2014年   38篇
  2013年   29篇
  2012年   14篇
  2011年   23篇
  2010年   28篇
  2009年   26篇
  2008年   15篇
  2007年   18篇
  2006年   11篇
  2005年   6篇
  2004年   7篇
  2003年   8篇
  2002年   8篇
  2001年   4篇
  2000年   6篇
  1998年   11篇
  1997年   7篇
  1996年   12篇
  1995年   5篇
  1994年   4篇
  1993年   13篇
  1992年   7篇
  1991年   7篇
  1990年   9篇
  1989年   7篇
  1988年   3篇
  1986年   6篇
  1985年   4篇
  1984年   6篇
  1983年   3篇
  1981年   3篇
  1978年   3篇
  1977年   4篇
  1976年   2篇
  1974年   2篇
  1973年   3篇
  1972年   3篇
  1971年   5篇
  1970年   3篇
  1969年   4篇
  1965年   4篇
  1963年   2篇
排序方式: 共有546条查询结果,搜索用时 46 毫秒
201.
202.
Closed, isolated small systems, as the representatives of a “unique-environmental feature”, are valuable natural laboratories for studying different biogeochemical processes. The saline Rogoznica Lake (“Dragon Eye”), situated on the Eastern Adriatic coast is such a system (10 276 m2, 15 m deep) typical of many stratified, sulfide rich water bodies. The depth of mixolimnion changes seasonally and it is greatly influenced by meteorological conditions, i.e. temperature and rainfall. Vertical mixing usually occurs during winter when cold, oxygen-rich water from the surface sinks downwards.  相似文献   
203.
We analyzed oceanographic, hydrologic and atmospheric conditions in the northern Adriatic (section between the Po River delta and Rovinj) from 1990 to 2004 in which extreme phytoplankton blooms appeared. The largest blooms occurred in February, March, July and October, and were higher in surface layers and in the western, more eutrophic part of the region. They often appeared when the Istrian Coastal Countercurrent (ICCC; strong southward current indicating a “closure” of the northern Adriatic circulation system) was pronounced. They seem to be related to the intensities of surface fluxes and Po River discharge rates. The blooms can float over the northern Adriatic for a long period (up to 30 days; typical for March) and can appear simultaneously in separate circulation systems with a different species distribution. Finally, we present a hypothesis based on comparisons of geostrophic currents and fish stock that specific February northern Adriatic oceanographic conditions play the key role in the Adriatic anchovy stock.  相似文献   
204.
Denamiel  Cléa  Pranić  Petra  Quentin  Florent  Mihanović  Hrvoje  Vilibić  Ivica 《Climate Dynamics》2020,55(9-10):2483-2509

This numerical work aims to better understand the behavior of extreme Adriatic Sea wave storms under projected climate change. In this spirit, 36 characteristic events—22 bora and 14 sirocco storms occurring between 1979 and 2019, were selected and ran in evaluation mode in order to estimate the skill of the kilometer-scale Adriatic Sea and Coast (AdriSC) modelling suite used in this study and to provide baseline conditions for the climate change impact. The pseudo-global warming (PGW) methodology—which imposes an additional climatological change to the forcing used in the evaluation simulations, was implemented, for the very first time, for a coupled ocean–wave–atmosphere model and used to assess the behavior of the selected storms under Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 greenhouse gas projections. The findings of this experiment are that, on the one hand, the AdriSC model is found capable of reproducing both the Adriatic waves associated with the 36 storms and the northern Adriatic surges occurring during the sirocco events and, on the other hand, the significant wave heights and peak periods are likely to decrease during all future extreme events but most particularly during bora storms. The northern Adriatic storm surges are in consequence also likely to decrease during sirocco events. As it was previously demonstrated that the Adriatic extreme wind-wave events are likely to be less intense in a future warmer climate, this study also proved the validity of applying the PGW methodology to coupled ocean–wave–atmosphere models at the coastal and nearshore scales.

  相似文献   
205.
Starting from the standpoint that there are seasonal differences of climate variations on both global and local level, the authors of this paper had focused on analyzing climatologic parameters in winter months. The trends of several important parameters were detected, with temperature and precipitation having increasing, but number of ice days and snow cover having decreasing trends. Spectral analysis showed repetitive nature of climatologic parameters, some of them having the same or similar periods of about 6 to 7 years, 10 to 12 or 17.5 years, and 22 to 24 years. The precipitation has periodicity of 8 and 14 years. Further analysis of the underlying structure of the data by principal component analysis detected three easily explained dimensions: Temperature-Snow, Precipitation-Cyclone and Spring-in-Winter dimension. The spectral analysis of three virtual variables obtained by principal component analysis confirmed good agreement of original variables with the virtual dimensions.  相似文献   
206.
We present a detailed radio-continuum study on Australia Telescope Compact Array (ATCA) observations of Large Magellanic Cloud (LMC) supernova remnant (SNR), MCSNR J0536–7038. This Type Ia SNR follows a horseshoe morphology, with a size 32 pc × 32 pc (1-pc uncertainty in each direction). It exhibits a radio spectrum α=?0.52±0.07 between λ=73 and 6 cm. We report detections of regions showing moderately high fractional polarisation at 6 cm, with a peak value of 71±25 % and a mean fractional polarisation of 35±8 %. We also estimate an average rotation measure across the remnant of –237 rad m?2. The intrinsic magnetic field appears to be uniformly distributed, extending in the direction of the two brightened limbs of the remnant.  相似文献   
207.
The predicted Draconid meteor shower outburst during October 2011 had been observed by a portion of the Croatian Meteor Network whose stations encountered clear weather. A total of 95 Draconid orbits have been calculated from 18 contributing stations, and in this paper we present results for 63 orbits obtained from the fully automatic observation and processing pipeline. Two methods of trajectory estimation were applied, showing better fit results using a linearly changing velocity model versus a constant velocity model. The estimated mean radiant position has been found to be at RA = 262.6°, Dec = +55.7°, with estimated geocentric velocity Vg = 20.7 km/s.  相似文献   
208.
On dynamical grounds Neptune's satellite Triton is believed to be a captured body. We present nondynamical arguments in favour of this idea.  相似文献   
209.
In this Letter we give a brief sketch of the problem of scientific knowledge as it has been elaborated by Pauli and Jung on a non-physical ground. In addition, we try to find arguments in favour of their opinion in the territory of physics. If these reasons hold indeed, then an incompatibility in space-time-matter relationship can be indicated.  相似文献   
210.
Zusammenfassung In Alkalisyeniten des Gipfels Crni Kamen, sw. von Prilep in Mazedonien, kommen hydrothermale Gänge mit schön kristallisierten Mineralen vor. Nebst kurz erwähnten, spärlich vorkommenden Sulfiden werden die Resultate der Untersuchungen des Alkaliamphibols, Mikroklins, Apatits Albits, Sphens, Quarzes und Hyalits gegeben. In diesem Gebiet wurden auch Davidit, Brannerit, Ilmenit und Magnetit gefunden. Selten findet sich regelmäßige Verwachsung des Ilmenits mit Rutil.
Summary In alkali syenites on the hill Crni Kamen, sw. from Prilep in Macedonia hydrothermal veins appear with well crystallized minerals. In addition to the briefly described scarcely appeared sulfides the results of the investigations of alkaliamphibole, microcline, apatite, albite, sphene, quartz and hyalite are reported. In this area were also recorded davidite, brannerite, ilmenite and magnetite. Oriented growth of ilmenite with rutile has been rarely found.


Mit 1 Textabbildung

Herrn Professor Dr.F. Machatschki zum 70. Geburtstag gewidmet.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号