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61.
帘蛤科一新种——扁平美女蛤Circe(Laevicirce)hongkongensis sp.nov.系于1988年采自香港大潭湾潮下带。新种的主要特征是两壳极扁平,铰合部宽阔,区别于本亚属的其他种。 相似文献
62.
Zongguo Huang 《海洋学报(英文版)》2003,22(3):467-482
From 1980 to 1998, biofouling communities in Hong Kong waters, the Zhujiang RiverEstuary and the Mirs Bay were studied and a total of 610 samples. The samples were collected from vessels, buoys, piers and cages. Totally, 340 species (see Appendix I ) have been recorded and identified, six of which are new. At the same time, research on the biology of the cirripede, bryozoan, polychaete and mollusc communities were also conducted. Twenty-three related papers have been published. This review summarizes works in Hong Kong over past twenty years, and some unpublished data are also reported. 相似文献
63.
64.
1 Introduction Thelifecycleofhorseshoecrabsislengthywhencom paredtoothermarinearthropodssuchasbluecrabsandshrimpspecies (Sekiguchietal.,1988) .Thetwospecies,TachypleustridentatusandCarcinoscorpiusrotundicauda,knowntooccurinHongKongrequire ,respectively ,betweenthirteentofourteenandtentoelevenyearstomaturebeforedepartingtheirnurserybeachesfordeeperwaters (ChiuandMorton ,1999a ;Sekiguchietal.,1988) .Thelivingenvironmentofthenurserybeacheswheretheeggsarelaidandincu bated ,andfromwhichtheyoun… 相似文献
65.
66.
Jianfa Shen 《The Professional geographer》2004,56(4):530-543
The rapid development in the Hong Kong‐Pearl River Delta (PRD) city‐region has taken place alongside complicated cross‐border governance. The framework of time‐space envelopes (TSEs) is adopted for a study of cross‐border governance in Hong Kong, especially in the role of the state, that is, the Hong Kong government, in cross‐border urban governance. This article argues that tension‐ free regional integration has never existed due to a complex governance network. The shift from “cross‐border protectionism” to “cross‐border free trade zone” in Hong Kong's cross‐border urban governance since 2001 is a result of the rearticulation of the state cutting through the geoeconomic and geopolitical TSEs. 相似文献
67.
68.
The Effects of Annual Harvesting on the Subsequent Phytomass and Species Composition of Grassland and Fernland: A Hong Kong Case 总被引:1,自引:0,他引:1
Anthropogenic grasslands mixed with fern and shrubland, on scales from metres to kilometres, are widespread in tropical Southeast Asia, and especially in southern China and adjoining regions where harvesting for domestic fuel is a major factor in their maintenance. Baseline surveys in grassland and fernland in 1989–90 and resurveys in 2001 of three 6 × 20 m plots in Wong Chuk Yuen, Hong Kong, showed substantial change in species composition and total aboveground phytomass as a result of annual harvesting, with more pronounced change in the fernland. Under harvesting pressure, the species composition of the grassland changed considerably, though the proportions of the various life‐forms did not. Ischaemum spp. and Miscanthus floridulus increased whereas Themeda gigantea died out while the proportion of other grass species remained much the same. Under the same regime the species composition and life‐forms of the fernland changed markedly. The proportion of Dicranopteris fern dropped substantially, though still comprising a third of the phytomass by 2001. The shrub Melastoma survived harvesting. A firebreak cut in the fernland became grassy under annual harvesting and remained grassy six years after cutting ceased. The annual harvests from the growth‐years 1991–2000 showed a substantial though variable increase in total phytomass. Analyses relating harvested phytomass with various climatic parameters showed no significant correlations. Some possible reasons for this are suggested. Although annual harvesting was clearly sustainable over the ten years of observation, the question of continued sustainability on sites harvested for centuries, the situation in much of southern China and parts of upland mainland Southeast Asia, remains unresolved. 相似文献
69.
Regional bias of landslide data in generating susceptibility maps using logistic regression: Case of Hong Kong Island 总被引:4,自引:0,他引:4
On the basis of 1,834 landslide data for Hong Kong Island (HKI), landslide susceptibility maps were generated using logistic
regression and GIS. Regional bias of the landslide inventory is examined by dividing the whole HKI into a southern and a northern
region, separated by an east-west trending water divide. It was found that the susceptibility map of southern HKI generated
by using the southern data differs significantly from that generated by using northern data, and similar conclusion can be
drawn for the northern HKI. Therefore, a susceptibility map of HKI was established based on regional data analysis, and it
was found to reflect closely the spatial distributions of historical landslides. Elevation appears to be the most dominant
factor in controlling landslide occurrence, and this probably reflects that human developments are concentrated at certain
elevations on the island. Classification plot, goodness of fit, and occurrence ratio were used to examine the reliability
of the proposed susceptibility map. The size of landslide susceptible zones varies depending on the data sets used, thus this
demonstrates that the historical landslide data may be biased and affected by human activities and geological settings on
a regional basis. Therefore, indiscriminate use of regional-biased data should be avoided. 相似文献
70.
Change of groundwater chemistry from 1896 to present in the Mid-Levels area, Hong Kong 总被引:1,自引:0,他引:1
In this study, groundwater quality information collected in 1896 (well waters), 1980/1981 (piezometric and seepage samples)
and 2002/2003 (seepage samples) in the regions centered by the Mid-Levels area, Hong Kong Island, was compared to illustrate
how groundwater quality has changed over a century and the processes controlling it. As shown by saline ammonia and nitrate
levels in the late nineteenth century, groundwater was severely polluted by widespread and obvious leakage from poorly designed
wastewater collection systems, although groundwater was still a drinking water source for local residents. The extremely high
residual chlorines in groundwater demonstrated that large doses of disinfection agents were added to wells at that time. In
view of the decline in saline ammonia and nitrate levels, groundwater became less organically polluted in the 1980s probably
due to significant improvement of the design of underground sewers. However, more leakage from sources such as salty flushing
water and fresh water pipes emerged in the past few decades which added complexity to groundwater chemical systems. Some chemicals
were used to identify possible locations of leakages. The temporal variations of the distribution of these chemicals over
the area may shed light on the rate of leakage. Leakage from service pipes seems to have improved from the early 1980s to
2002/2003. However, the area is still suffering from widespread and small-scale leakage from service pipes. More efforts should
be paid to control small leakages in the future. The findings will be instructive to various government organizations such
as the Water Supplies Department and Drainage Services Department to identify possible locations of unobvious leakages in
the area. 相似文献