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51.
Species diversity in native fish community in Japan: comparison between non-invaded and invaded ponds by exotic fish 总被引:4,自引:1,他引:4
The relationship between invasions by two exotic fishes (Micropterus salmoides and Lepomis macrochirus) and species diversity in native fish communities was studied in 14 Japanese farm ponds. We found that mean number of species in native fish communities was three times higher in the ponds without the exotic fish than in the ponds with them. Further, negative relationships were observed between abundance of the two exotic fish and the total abundance of native fish communities. Our results suggest that invasions by the two exotic fish caused serious depletion of native fish communities, although another process can also be considered , that is, that ponds with poor native fish communities were prone to colonization by these exotic fish. 相似文献
52.
53.
Kelvin Chen Mark Massaad Ricardo De Lima Ana Rainho Ricardo Rocha 《Entomological Science》2023,26(3):e12558
Giant water bugs (Hemiptera: Belostomatidae) are key predators in freshwater ecosystems and have been reported to feed on several species of vertebrates, including fishes, amphibians and reptiles. Here, we report the opportunistic predation of an adult female vesper bat (Afronycteris nana) by a giant water bug (Lethocerus cordofanus) in a temporary pond in a rice paddy in Guinea-Bissau, West Africa. To our best knowledge, this is the first instance of natural predation upon a mammal by a giant water bug to be documented in a scientific report. 相似文献
54.
宽叶香蒲净化塘系统净化铅/锌矿废水效应的研究 总被引:30,自引:1,他引:29
研究了以宽叶香蒲(Typha latifolia)为优势群落的净化塘系统来处理广东韶关凡口铅/锌矿选矿废水。经5年多的监测结果表明,该系统能有效地净化铅/锌石广废水。在进入净化塘系统前,未处理的废水合有高浓度的悬浮物(4 635mg/L)和重金属[Fb(1.61mg/L)、Zn(1.96mg/L)和Cd(0.022mg/L)]等,经过净化后,水质明显改善,pH从8.03下降到7.74,总悬浮物去除率达99%,Pb去除率为90%,Zn和Cd去除率为84%,其它重金属如Cu、Fe和Al等也都有不同程度的降低。 相似文献
55.
Joseph Rasowo 《Hydrobiologia》1992,247(1-3):209-214
Pond culture of brackishwater prawns and shrimps has recently generated much interest in Kenya. The mangrove areas are the target zones for the construction of these ponds. With the increasing awareness of the unique ecological role played by the mangroves, there is an urgent need to stop the conversion of mangrove swamps into aquaculture ponds. To develop pond aquaculture without destroying the mangroves, a shift from tide-fed to pump-fed pond systems is recommended in order to divert the farming from the mangroves to higher grounds. Mangrove-friendly mariculture practices like pen, cage and raft culture are discussed. Methods of efficiently utilising the already destroyed mangrove areas are considered. 相似文献
56.
本文以东南亚园林中的两个常见元素—盆栽和方池为例,呈现了印度文明对东南亚园林的影响。在此基础上,通过案例呈现了东南亚园林的宗教和哲学内涵以及相应的常见造园手法。以此指出,东南亚园林不只是对中国、欧洲园林的模仿,其园林设计受印度影响较大,且有一以贯之的逻辑,并能够承载深刻的思想内涵 相似文献
57.
碱蓬浮床对海水养殖尾水中氮磷修复效果研究 总被引:1,自引:0,他引:1
海水养殖尾水中总氮、总磷超标是引起沿海水体富营养化的主要原因,为研究碱蓬浮床对海水养殖尾水中氮磷的去除效果,该研究设计加入碱蓬(Suaeda salsa)浮床和不加浮床的两组对比实验,通过比较修复前后碱蓬株高、生物量、含水率、根长以及各部位氮、磷的含量变化,以及水体中总氮(TN)和总磷(TP)的去除效果,探究浮床中碱蓬对总氮和总磷的吸收及其生长特性,验证碱蓬浮床对海水养殖废水中氮、磷等的去除能力。结果表明:浮床中碱蓬株高、鲜重、干重、含水率、根长较修复前均有显著增加,说明浮床中盐生植物碱蓬能够适应含海水养殖尾水水培环境;经碱蓬浮床修复,水体中总氮、总磷均明显下降,其中碱蓬对海水养殖尾水中的总氮总磷去除贡献率分别为16.10%和78.15%,浮床中碱蓬会在叶片和根系中积累氮磷。 相似文献
58.
Spatial and temporal distribution of the zoobenthos community in a woodland pond (Switzerland) 总被引:2,自引:1,他引:1
Spatial and temporal changes of zoobenthos composition and density were assessed in a woodland pond, near Geneva (Switzerland), by monthly sampling (during 15 months), on the three main substrates: a submerged macrophyte (Chara sp.), an emergent macrophyte (Typha latifolia stems) and allochthonous detritus (oak leaves).Many taxa showed preferences for one or two of the substrates, as expressed by differences in densities, but few taxa presented an exclusivity for one substrate. Zoobenthos densities (per m2 of pond bottom) were largely dominated on all substrates and seasons by Chironomidae and Oligochaeta. Other dense macroinvertebrates included Ostracoda (on Chara and Typha stems), Gastropoda (on Typha stems), Ephemeroptera (all substrates), and Ceratopogonidae (on Typha stems).The magnitude of temporal differences in densities was expressed by the ratio of maximal to minimal monthly densities and reached values between 2.8 to 11.8. On all substrates the highest monthly densities were observed in summer or beginning of autumn. The temporal changes in densities were strongly influenced by the life cycles of the invertebrates: presence of numerous young individuals in summer (for example Cypridopsis vidua, Cloeon dipterum, Caenis horaria, Ferrissia wautieri), and emergence (for example Chironomidae in April). Fluctuations in densities, especially on Chara and leaves, were also attributed to modification of substrate condition (surface availability, stage in the decomposition or senescence process). Temporal fluctuations of densities were compared with other lentic water bodies: highest densities showed a common trend, occurring between end of spring and beginning of autumn. 相似文献
59.
Biomass dependent interactions in pond ecosystems: responses of lower trophic levels to fish manipulations 总被引:3,自引:3,他引:0
Tátrai István Oláh János Paulovits Gábor Mátyás Kr´lmán Kawiecka Barbara J. Józsa Vilmos Pekár Ferenc 《Hydrobiologia》1997,345(2-3):117-129
The effects of mature benthivorous cyprinid fish and theirrecruitment on sediment resuspension, turbidity, phyto- andzooplankton, and benthic macroinvertebrates were studied in fourexperimental ponds. The ponds were stocked with bream (Abramisbrama L.), white bream (Blicca bjoerkna L.), roach (Rutilus rutilus L.) and wild carp (Cyprinus carpio L.) of3+–5+ age classes at standing crop biomass varying from 0 to500 kg ha-1. Cyprinids caused an increase in sedimentresuspension and in turbidity, in proportion to their biomass. Meancrustacean biomass did not significantly affect phytoplanktonbiomass due to intense grazing by fish during spring. Ponds withhigh fish stocks showed reduced midge biomass and vegetation coverand increased biomass of predatory invertebrates. 相似文献
60.
This paper presents the results of an investigation on the distribution of210Po in Mutharasanallur pond ecosystem. It has been demonstrated that210Po is non-uniformly distributed within the ecosystem. The results of the study show a dissolved210Po concentration in pond water of 1 4mBq 1−1. The sediment samplso recorded a210Po activity of 59 9 Bq kg−1. The aquatic organisms showed differential accumulation of the radionuclide with enhanced bioaccumulation in soft tissues
and muscle. The210Po activity in the biota fell within the range of 1·2–53 3 Bq kg−1 (wet wt). The bivalve mussel,Lamellidens marginalis was identified to accumulate higher concentration of210Poin soft tissues, suggesting that these organisms could serve as a bio-monitor of210Po radionuclide in a freshwater system. The concentration factors of210Po for the biotic components ranged from ∼102–∼104. Analyses of the results indicate that prawn and fish represent an important source of supply of210Po to humans via dietary intake. Results of210Po activity in the abiotic and biotic components of the pond ecosystem were higher when compared with those of Cauvery river
system, the primary water source of the pond. 相似文献