全文获取类型
收费全文 | 66篇 |
免费 | 0篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 6篇 |
地球物理 | 7篇 |
地质学 | 24篇 |
海洋学 | 14篇 |
天文学 | 12篇 |
自然地理 | 2篇 |
出版年
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 10篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 5篇 |
2012年 | 2篇 |
2011年 | 1篇 |
2010年 | 4篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 5篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有66条查询结果,搜索用时 31 毫秒
41.
G. Tsiropoula K. Tziotziou T. Wiegelmann Th. Zachariadis C. Gontikakis H. Dara 《Solar physics》2007,240(1):37-48
The temporal variation of a loop system that appears to be changing rapidly is examined. The analyzed data were obtained on 15 May 1999, with the Transition Region and Coronal Explorer (TRACE) during an observing campaign and consist of observations in the Fe ix/Fe x 171?Å and Fe xii 195?Å passbands taken at a cadence of ~10 min. The special interest in this loop system is that it looks like one expanding loop; however, careful examination reveals that the loop consists of several strands and that new loop strands become visible successively at higher altitudes and lower loop strands fade out during the one hour of our observations. These strands have different widths, densities, and temperatures and are most probably consisting of, at least, a few unresolved thinner threads. Several geometric and physical parameters are derived for two of the strands and an effort is made to determine their 3D structure based on the extrapolation of the magnetic field lines. Electron density estimates allow us to derive radiative and conductive cooling times and to conclude that these loop strands are cooling by radiation. 相似文献
42.
Dara H. Wilber Douglas G. Clarke Jenine Gallo Catherine J. Alcoba Ann M. Dilorenzo Sarah E. Zappala 《Estuaries and Coasts》2013,36(6):1304-1318
A long-term (2002–2011), spatially robust, ichthyoplankton sampling program conducted in the New York/New Jersey Harbor produced 3,033 epibenthic samples from which the relationships between winter flounder egg and larval distributions and environmental parameters were examined. Variations in water temperature, sediment characteristics, and tidal phase were all significantly associated with egg distributions. Inferences about spawning habitats were based on the presence of early-stage eggs (ES1 and ES2). In the Lower Bay (LB), these habitats were primarily non-channel and characterized by more sandy substrates, averaging 96.5 % sand, 2.3 % silt/clay, 0.2 % total organic carbon (TOC), and shallower water (average depths of 5.3 m) compared to LB non-channel stations without ES1 and ES2 eggs (50.2 % sand, 42.0 % silt/clay, 2.1 % TOC, and 7.9 m depths). Occurrences of all stages of eggs in channels were associated with strong tides and severe cold winter water temperatures. These conditions increase the probability of egg transport from shallow spawning sites through increased vertical mixing (strong tides) and delayed development that prolongs the risk of displacement (cold temperatures). Yolk-sac (YS) and Stage-2 larvae were smaller in 2010 when spring water temperatures were highest. Overall, YS larval size decreased with warmer winters (cumulative degree-days for the month preceding peak YS larval collections, r 2?=?0.82, p?<?0.05). In all years, YS larvae collected in LB were smaller and Stage-3 larvae collected in channels were larger and possibly older than those from non-channel habitat. Because estuarine winter flounder populations are highly localized, adverse effects experienced during egg and larval stages are likely to propagate resulting in detrimental consequences for the year class in the natal estuary. 相似文献
43.
We have used a 5.5 min time-sequence of spectra in the Fe i lines 5576 (magnetically insensitive), 6301.5 and 6302.5 (magnetically sensitive) to study the association of concentrated magnetic regions and velocity in the quiet Sun. After the elimination of photospheric oscillations we found downflows of 100–300 m s –1, displaced by about 2 from the peaks of the magnetic field; this velocity is comparable to downflow velocity associated with the granulation and of the same order or smaller than the oscillation amplitude. Quasi-periodic time variations of the vertical component of the magnetic field up to ± 40% were also found with a period near 250 s, close to the values found for the velocity field. Finally we report a possible association of intensity maxima at the line center with peaks of the oscillation amplitude. 相似文献
44.
A. V. Drits M. D. Kravchishina A. F. Pasternak A. N. Novigatsky O. M. Dara M. V. Flint 《Oceanology》2017,57(6):841-854
The role of zooplankton in the vertical mass flux in the Kara and Laptev seas was studied during cruise 63 of the R/V Akademik Mstislav Keldysh in August–October 2015. Mass fluxes were estimated using sediment trap samples. The maximum values of the total vertical flux (19600 mg m?2 day?1) and particulate organic carbon (POC) flux (464 mg C m?2 day?1) were measured close to the Lena River Delta in the Laptev Sea. In the Kara Sea, the total flux (80–2700 mg m?2 day?1) and the POC flux (17–130 mg C m?2 day?1) were substantially higher than the estimates published earlier. The fecal pellet flux varied from 2 to 92 mg C m?2 day?1 and made up 4–190% of the total organic carbon flux. The mineral composition of fecal pellets largely mirrored that of suspended particulate matter. Clay minerals in the fecal pellets were more abundant than in particulate matter in the areas with noticeable freshwater impact. The flux of zooplankton carcasses varied from 0.1 to 66.4 mg C m?2 day?1 and made up 0.2–72% of total POC flux. The results are discussed in relation to the abundance and composition of zooplankton, the concentration and composition of suspended particulate matter, hydrophysical conditions, and methods of sample preparation for analysis. 相似文献
45.
Spring and Summer Larval Fish Assemblages in the Surf Zone and Nearshore off Northern New Jersey,USA
Kenneth W. Able Dara H. Wilber Angela Muzeni-Corino Douglas G. Clarke 《Estuaries and Coasts》2010,33(1):211-222
Larval fish use of surf zone and nearshore habitats at northern latitudes has received little attention. Consequently, potential
impacts of beach nourishment and other forms of disturbance are not well understood. This study, on a northwestern Atlantic
coastline spanning May through July over 4 years, demonstrates that recently hatched larvae are common in both surf zone and
nearshore habitats. Taxonomic compositions of surf zone and nearshore assemblages were similar to each other and those from
an adjacent estuary. An influence of upwelling events was apparent in coincident changes in abundance and/or size of several
species in the surf zone. Other changes over the late spring–summer transition, including buoyancy-driven flows from the Hudson
River plume, demonstrate the dynamic nature of larval fish assemblages in the New York Bight area. 相似文献
46.
This paper presents a new statistical method for assimilating precipitation data from different sensors operating over a range of scales. The technique is based on a scale-recursive estimation algorithm which is computationally efficient and able to account for the nested spatial structure of precipitation fields. The version of the algorithm described here relies on a static multiplicative cascade model which relates rainrates at different scales. Bayesian estimation techniques are used to condition rainrate estimates on measurements. The conditioning process is carried out recursively in two sweeps: first from fine to coarse scales and then from coarse to fine scales. The complete estimation algorithm is similar to a fixed interval smoother although it processes data over scale rather than time. We use this algorithm to assimilate radar and satellite microwave data collected during the tropical ocean–global atmosphere coupled ocean–atmosphere response experiment (TOGA-COARE). The resulting rainrate estimates reproduce withheld radar measurements to within the level of accuracy predicted by the assimilation algorithm. 相似文献
47.
Large-scale fields of soil moisture are forced by atmospheric precipitation and radiative forcing. When these forcing factors
are themselves influenced by surface and soil moisture processes, the result is a nonlinear land-atmosphere system with inherent
feedback mechanisms that may strongly modulate variability in climate. Given such feedbacks, simple randomness in the forcing
factors may be manifested as a complex statistical signature in the surface hydrology. In this paper, we investigate the impacts
of non-Gaussian and colored-noise on the probability distribution of soil moisture resulting from the statistical-dynamical
land-atmosphere interaction model of Rodriguez-Iturbe et al. (1991). Persistence of hydroclimatologic anomalies as characterized
by the correlation time scale of soil moisture is discussed. 相似文献
48.
Georgakilas A. A. Dara H. Zachariadis Th. Alissandrakis C. E. Koutchmy S. 《Solar physics》1997,172(1-2):133-138
We analyze a time series of high-resolution observations near the limb, in the continuum, in the Mg b
1 line (-0.4 Å off line center), and in the wings of H (+0.75 Å). The observations were obtained with a CCD camera at the Vacuum Tower telescope of the Sacramento Peak Observatory. We study the association of facular points, as they appear at different heights of the solar atmosphere (continuum, b
1 - 0.4 Å, H + 0.75 Å) with the feet of fine dark mottles. 相似文献
49.
Jeziorski Adam Nelligan Clare Corrigan Dara Meyer-Jacob Carsten Paterson Andrew M. Smol John P. 《Journal of Paleolimnology》2021,66(4):371-387
Journal of Paleolimnology - Peninsula Lake, Ontario, Canada, is a Precambrian Shield lake that has experienced many environmental stressors since European settlement of the watershed in the... 相似文献
50.
D. F. Hamamin R. A. Qadir S. S. Ali A. P. Bosch 《International Journal of Environmental Science and Technology》2018,15(1):173-184
Fresh groundwater from intergranular and carbonate aquifers are considered as the valuable resources for domestic, agricultural and industrial water supplies of the Iraqi Kurdistan Region. A comprehensive approach to groundwater protection using the intrinsic vulnerability, hazard and risk intensity mapping was proposed by the European COST Action 620. The current article applied all the components of the above mentioned Pan-European approach to assess the risk harmfulness in the Sulaimani sub-basin by combining hydrogeological parameters using the DRASTIC system and the hazard components by taking the product of the weighted hazard value (HI), the ranking factor (Qn) and the reduction factor (Rf). The hazard map was constructed from twenty-six hazard feature types of the point, line and polygon. Their distributions, extents and of harmfulness degrees vary sharply from one place to another. Results of the risk intensity map divided the area into five classes as “no or very low, low, moderate, high and very high” risk zones. Fortunately, the majority of the area of interest is classified as very low to low contamination potential due to the limited impact of hazards as well as low groundwater vulnerabilities. The zones with moderate-risk potentials clustered in industrialized areas. 相似文献