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61.
John Holmes 《The Australian geographer》2011,42(1):53-68
Entrenched contests about the future of Cape York Peninsula's lands, waters and people have for long received national prominence. In the federal arena, this has climaxed with the campaign to overturn the State's declarations on wild rivers. Initially pursued as a means of influencing decisions on the determination of the government in a finely balanced federal parliament, it has been retained as an early test of the survivability of the minority Labor government. The peninsula's prominence is founded on its iconic conservation status and the continuity of Aboriginal occupance of their country, reinforced by the formidable capabilities of Indigenous and conservationist leaders. Contests are characterised by their complexity, durability and intractability. Contests are bedevilled by shifting alliances and schisms within Indigenous and conservationist constituencies. Increasingly potent is the schism between modernist/reformist/regionalist visions of Indigenous futures, forcefully presented by Noel Pearson against more traditionalist/localist visions held by many community leaderships. Other participants, notably conservationists, State politicians and bureaucracies have needed to align their policies around these contested visions. Over the last two decades, policies of State Labor governments have maintained some continuity, being pro-active on conservation goals, selectively supportive of Aboriginal advancement, necessarily passive in the determination of land claims, reactive in the resolution of land tenures and property rights, and inconsistent and ineffectual in conflict resolution and in providing leadership in shaping sustainable, multifunctional futures, attuned to the peninsula's unique challenges and potentials. 相似文献
62.
A suite of surface sediment samples from three Icelandic lakes was analysed for subfossil chironomid head capsules, and a
quantitative July air temperature inference model was applied to the data to investigate whether there was significant variability
among samples taken from a lake. Ordination and simple regression methods were used to analyse the relationships between environmental
and sedimentological variables and the chironomid assemblages and inferred temperature data. Substrate was the most important
influence on the chironomid assemblages and inferred temperatures, while water depth at the sampling location had no relationship
with the chironomid-inferred temperatures. Within-lake variability of the chironomid assemblages and their inferred temperatures,
however, were not significant statistically, suggesting that in lakes of western and northwest Iceland within-lake sampling
location has no effect on the data obtained, and therefore on training set samples. 相似文献
63.
Rebecca M. Briant Martin R. Bates Steve Boreham Nigel G. Cameron G. Russell Coope Michael H. Field B. Marcus Hatch Jonathan A. Holmes David H. Keen Aiobhean A. Kilfeather Kirsty E.H. Penkman Rianne M.J. Simons Jean-Luc Schwenninger Francis F. Wenban-Smith Nicola J. Whitehouse John E. Whittaker 《Proceedings of the Geologists' Association. Geologists' Association》2019,130(1):1-26
Constraining the speed of sea level rise at the start of an interglacial is important to understanding the size of the ‘window of opportunity’ available for hominin migration. This is particularly important during the last interglacial when there is no evidence for significant hominin occupation anywhere in Britain. There are very few finer grained fossiliferous sequences in the Channel region that can be used to constrain sea level rise and they are preserved only to the north of the Channel, in England. Of these, the sequence at Stone Point SSSI is by far the most complete. Data from this sequence has been previously reported, and discussed at a Quaternary Research Association Field Meeting, where a number of further questions were raised that necessitated further data generation. In this paper, we report new data from this sequence – thin section analysis, isotopic determinations on ostracod shells, new Optical Stimulated Luminescence ages and Amino Acid Recem analyses. These show early sea level rise in this sequence, starting during the pre-temperate vegetation zone IpI, but no early warming. The implications of this almost certainly last interglacial sequence for the human colonisation of Britain and our understanding of the stratigraphic relationship of interglacial estuarine deposits with their related fluvial terrace sequences is explored. 相似文献
64.
We present a method for measuring 15N–NH4+ in marine, estuarine and fresh waters. The advantage of this method is that it is broadly applicable to all types of water and it allows measurements in samples with lower ammonium concentrations than has previously been possible. The procedure is a modification of the ammonia diffusion method and uses large sample volumes (often 4 l) to obtain sufficient N for isotope ratio mass spectrometric analysis. Large volume samples have not previously been used with the diffusion procedure because isotopic fractionation occurs due to incomplete recovery of ammonium. However, the method we present accounts for this fractionation and allows precise correction of measured δ15N values. 相似文献
65.
The pulsed plasma probe technique has been expanded to include simultaneous determinations of absolute electron density, density fluctuations, electron temperature, and mean-ion-mass with resolution limited only by probe geometry, sheath size, and telemetry. The technique has been designed to test for coupling of electron density variations and ion composition irregularities in multi-component plasmas by the comparison of electron density fluctuation power spectraP
N(k) and a newly-developed diagnostic parameter, the mean-ion-mass fluctuation spectraM
i/M
iP
M(k). In addition, the experiment extends satellite-borne irregularity spectral analyses down to the 5–20 m range while attempting to identify F-region plasma instability processes on the basis of characteristics inN
e,T
e, N
e,P
N,M
i, andP
M. Initial results demonstrate the expanded diagnostic capability for high spatial resolution measurements of mean-ion-mass and provide experimental evidence for the role of ion composition in multi-stepped plasma instability processes. Specific results include a spectral indexX
n inP
N=A
nf–X
n of 1.6–2.9 over the wavelength range from 1 km to 6 m under conditions identified with an unstable equatorial nighttime ionosphere. Simultaneous measurements ofM
i/M
i(P
M=A
M
f
–X
m) andN
e/N
e(P
N=A
n
f
–X
n) have shown a general behavior tending to lower power (A
m<A
n) and softer spectra (X
m<X
n) in ion mass fluctuations when compared with fluctuations in total plasma density. Limited analyses of the two power spectral elements raise hopes for the differentiation between plasma mechanisms that can lead to similar indices inP
N.Paper originally submitted to the journalSpace Science Instrumentation. 相似文献
66.
Jonathan A. Holmes Patrick A. Fothergill F. Alayne Street-Perrott R. Alan Perrott 《Journal of Paleolimnology》1998,20(4):369-380
The ostracod record from Kajemarum Oasis in the Sahel zone of Northeastern Nigeria covers the last c. 4000 cal. years of a 5500 cal. year lake-sediment sequence. The first appearance of ostracods, around 4000 cal. yr BP, reflects the switch from a very dilute lake during the mid-Holocene, to slightly oligosaline conditions that favoured the occurrence and preservation of ostracods. Between 3800 and 3100 cal. yr BP, the lake remained permanent and fresh or slightly oligosaline, with a Ca-Mg-HCO3 composition. A rise in salinity c. 3100 cal. yr BP, accompanied by a change to more variable conditions on a seasonal to interannual timescale, led to the influx of more-euryhaline taxa. Oligosaline conditions continued between 3100 and 1500 cal. yr BP. Around 1500 cal. yr BP, there was a sharp rise in salinity, probably accompanied by a shift to Na-CO3-type water, with marked seasonal and interannual variability. Salinity decreased after 900 cal. yr BP, although short-term variations were marked between 900 cal. yr BP and the top of the sequence, 95 cal. yr BP. Changes in the species assemblages and ostracod abundance were a response to climate-driven variations in the seasonal and interannual stability of the lake, together with changes in its salinity and solute composition, but there is no simple relationship between ostracod faunas and salinity. Within Kajemarum, there is no evidence of ostracod assemblages typical of deep, fresh water, nor of hypersaline Na-Cl waters. The sediments associated with the freshest waters at Kajemarum did not favour ostracod preservation, and the driest climatic conditions were associated with oligosaline to mesosaline water of Na-CO3-type. The species-poor assemblages reflect the short-term instability of the lake, coupled with the limited opportunities for the colonisation of this isolated basin. 相似文献
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