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喀斯特洞穴旅游资源的开发与利用的研究一直是旅游洞穴研究的重点,溶洞旅游资源的合理开发对区域旅游发展有着重要的促进作用。在收集二手资料和实地考察的基础上,本文分析了江西溶洞旅游资源的地理分布和景观特征,探讨了旅游开发模式和相应对策,得出以下研究结论:江西省岩溶洞穴分布在全省9个地级市的28个县(区),集中分布在赣东北和赣西的山地、丘陵地区。溶洞形态与结构类型丰富,并具有鲜明的特色,洞内景观形态奇特;部分溶洞有悠久的开发历史,具有重要的科学文化价值和历史文化价值。根据溶洞的资源特色、区位、区域经济发展水平等旅游开发主导因素,旅游开发模式可分为独立型、组合型和依托型3种类型;采用主题式开发、科学规划旅游线路、将溶洞观光旅游与科考探险相结合、加大对溶洞旅游的宣传是开发的对策。 相似文献
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The life habits and microhabitat selection of speleophilic gobiid fishes were investigated on the Balearic Island of Ibiza (western Mediterranean Sea). Corcyrogobius liechtensteini (Kolombatović, 1891) was the most frequent species within submarine crevices, cavities and caves. Didogobius splechtnai Ahnelt & Patzner, 1995 co-occurred with C. liechtensteini in several cases but showed a clear spatial separation based on a different microhabitat preference. The microhabitat selection of both species was confirmed by habitat-choice experiments in anaquarium. Corcyrogobius liechtensteini was frequent in depths between 5 m and 25 m and attained abundances of 14.2 individuals · m−2 . This species inhabited the ceilings and upper parts of the walls within the caves. D. splechtnai was mainly found between 7 m and 11 m and showed abundances of approximately 2 indivi-duals · m−2 . This species occupied the fine sediment bottoms in the innermost parts of crevices and caves. The growth and the maximum age of both species were determined by length-frequency distributions. The overall sex ratio from catches of three different years are given for C. liechtensteini . 相似文献
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吉林省蛟河市拉法山白岗岩洞穴群成因浅析 总被引:1,自引:0,他引:1
吉林省蛟河市拉法山发现的白岗岩洞穴共有五层,三十个。其成因有构造坍塌洞;岩浆气泡洞和人工开凿洞。形成时代大约距今一亿年到几百万年之间。世界上的洞穴大多是石灰岩溶洞,其它岩石类型的洞穴比较少见,白岗岩洞穴则更少见,像拉法山的白岗岩洞穴数量之多、规模之大在国内外实属罕见。 相似文献
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Sponge waste that fuels marine oligotrophic food webs: a re‐assessment of its origin and nature 下载免费PDF全文
Manuel Maldonado 《Marine Ecology》2016,37(3):477-491
It has recently been realized that sponges take up much of the dissolved organic matter (DOM) available in the water of reefs. The energy derived from this DOM is suggested to be invested in renewing the sponge filter cells (choanocytes) every few hours, generating an outflow of detrital particulate organic matter (POM) that is rapidly ingested by other invertebrates. By this DOM‐to‐POM recycling, sponges are proposed to fuel the food web of oligotrophic marine communities, including reefs, caves and deep‐sea environments. In four species studied herein by electron microscopy, the POM found in the outgoing aquiferous canals had a complex composition, with large between‐species differences. It may include choanocytes (0–52%), and also mesohyl cells, such as archeocytes (9–20%) and spherulous, and granular cells with inclusions (27–90%). Exocytosed vesicles also occurred. Surprisingly, to end up into the outgoing canals, the internal mesohyl cells squeezed between the epithelial cells (endopinacocytes) of the canal wall. Mesohyl cells were also able to transfer their inclusions to the endopinacocytes, which in turn extruded their acquired vesicle loads into the canal lumen. The unanticipated abundant participation of mesohyl cells and endopinacocytes in the production of POM appears to be an ordinary process that occurs continuously in the sponges, mostly related to elimination of digestion leftovers and excretion by‐products. Therefore, POM is generated by sponges irrespective of whether the primary food source is particulate (evidence from this study) or DOM (previous literature). Altogether, these results indicate that the cellular mechanisms behind the relevant organic‐matter recycling carried out by sponges are more diverse than initially anticipated. The varying ratios of choanocytes/mesohyl cells in the POM across species suggest that different sponge species may impact differently the energetics of food webs of the respective oligotrophic habitats where they dominate. 相似文献
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Vasilis Gerovasileiou Eleni Voultsiadou Yiannis Issaris Argyro Zenetos 《Marine Ecology》2016,37(2):239-256
The number of alien species in the Mediterranean Sea is increasing rapidly, but few attempts have been made to evaluate impacts on specific habitat types. The present study investigated alien biodiversity in Mediterranean marine caves, both by contributing new records of Eastern Mediterranean cave aliens, and by reviewing the scattered existing literature; the main goals were to highlight potential impacts and investigate the importance of cave environments for the expansion of alien species. Seven new alien species were found in marine caves of the Aegean and Ionian seas, raising the total number of aliens reported from Mediterranean marine caves to 56 species, classified as molluscs, cnidarians, bryozoans, polychaetes, crustaceans, macroalgae, fishes and tunicates. Most cave aliens (66%) were recorded from the Southeastern Levantine coasts, specifically from Lebanese caves. Shipping and Lessepsian migration have been suggested as the main pathways of alien introduction into caves of the Mediterranean Sea. The comparison of alien cave biodiversity with the updated Mediterranean alien inventory (32 species added to the latest inventory) showed similar patterns and trends for species richness, biogeographical origin and major introduction pathways, corroborating previous findings on the high local representativeness of Mediterranean cave biodiversity. Alien species seem to have invaded mostly the entrance and semi‐dark zones of shallow and/or semi‐submerged caves and tunnels, whereas only a few have reached the dark inner sectors or caves of the anchialine type; thus, the unfavourable cave environment seems to be naturally protected from impacts related to opportunistic invasive species, at least to a certain point. Currently there is no research confirming any direct impacts of alien biota on the native cavernicolous one. However, some issues have emerged, implying potential threats that need to be further explored: (i) the presence of a considerable proportion of aliens in most studied marine caves of the Southeastern Mediterranean basin, (ii) the recently observed population explosion of alien cave‐dwelling fishes in the same area, (iii) several indications that alien diversity in marine caves is much higher than we know today. Quantitative surveys and monitoring schemes are needed in order to evaluate potential effects of alien diversity on cave community structure and the role of marine caves as stepping stones for its expansion in the Mediterranean. 相似文献