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91.
Site fidelity,residency, and abundance of bottlenose dolphins (Tursiops sp.) in Adelaide's coastal waters,South Australia
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Little is known about the ecology and behavior of southern Australian bottlenose dolphins (Tursiops sp.). This hinders assessment of their conservation status and informed decision‐making concerning their management. We used boat‐based surveys and photo‐identification data to investigate site fidelity, residency patterns, and the abundance of southern Australian bottlenose dolphins in Adelaide's coastal waters. Sighting rates and site fidelity varied amongst individuals, and agglomerative hierarchical cluster analysis led to the categorization of individuals into one of three groups: occasional visitors, seasonal residents, or year‐round residents. Lagged identification rates indicated that these dolphins used the study area regularly from year to year following a model of emigration and reimmigration. Abundance estimates obtained from multisample closed capture‐recapture models ranged from 95 individuals (SE ± 45.20) in winter 2013 to 239 (SE ± 54.91) in summer 2014. The varying levels of site fidelity and residency, and the relatively high number of dolphins found throughout the study area highlights the Adelaide metropolitan coast as an important habitat for bottlenose dolphins. As these dolphins also appear to spend considerable time outside the study area, future research, conservation, and management efforts on this population must take into account anthropogenic activities within Adelaide's coastal waters and their adjacencies. 相似文献
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93.
Jean-Luc Jung Wim C. Mullié Moulaye Mohamed Wagne Abdellahi Samba Ould Bilal Zein El Abidine Ould Sidaty 《Marine Biology Research》2016,12(1):66-75
The surveillance of marine mammal strandings within the framework of a biomonitoring scheme for the Mauritanian coast led to the discovery in 2013 of a 3.98?m long, juvenile rorqual Balaenoptera sp. in an advanced state of decomposition near Chott Boul (16°32.488′N, 016°27.0317′W). Photographs and skin samples were taken, but the specimen could not be collected. Based on limited morphological evidence, only Balaenoptera edeni and B. omurai were plausible. Sequences of three mtDNA regions, i.e. parts of the cox1 and the cytb genes as well as the D-loop, for a total of 2636?bp (> 16% of the mitogenome) identified the specimen as an Omura's whale, B. omurai, the first record in the Atlantic Ocean and at least 11,400?km away from its closest known range in the SW Indian Ocean (Madagascar). The question of whether the specimen is a vagrant or belongs to an unrecognized Atlantic population is discussed. Advection by currents or transport on a ship's bow bulb following collision are discarded. Circumstances (juvenile status, great distance from Indo-Pacific, necessary inter-oceanic passage through cold temperate waters) may slightly favour the hypothesis that B. omurai, if rare, could be autochthonous in the Atlantic. Beach surveys remain a useful tool to assess trends in cetacean species composition, to detect unusual mortality events and to help assess the impacts of anthropogenic activities. This is particularly applicable to remote areas where the marine mammal fauna is poorly known and where fisheries effort is high, such as the Mauritanian coast. 相似文献
94.
Based on the diagnostic morphological characters of the Arundo taxa, and after both field and herbarium observation, three species (A. micrantha, A. plinii and A. donax) were found along the eastern Adriatic coast. Altogether, 50 phytocoenological relevés from Arundo stands were collected in Croatia, Montenegro and Albania between 2010 and 2013. Three associations with a predominance of Arundo species were determined: Arundinetum plinianae, Arundinetum micranthae and Arundini donacis–Convolvuletum sepium. Among them, Arundinetum micranthae is described and proposed as a new association, belonging to the Artemisietea vulgaris class. It occurs frequently along the coastal belt between the cities of Split and Dubrovnik in South Croatia. The syntaxonomy of the associations is discussed and comparison with similar communities from Italy is made. The vegetation and floristic structure of the associations is discussed as a potential basis for biodiversity conservation programmes and for evaluating the state of these ecosystems in the future. 相似文献
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96.
Pinewoods are distinctive environmental elements in the Mediterranean coastal area and have both natural and historical significance. From the evening of March 4th to the morning of March 5th, 2015, a severe and unusual windstorm occurred in the Tuscany region of central Italy with wind gusts over 120 km/h. The windstorm caused vast damage to the anthropic and natural environment and wounded numerous trees in the renowned pinewoods of Parco della Versiliana in the Tyrrhenian coastal area. The meteorological calamity provided the opportunity to i) date the onset of the artificial plantation of the present Italian stone pine (Pinus pinea L.) forest to the 1820s, ii) build a long-term tree-ring chronology of the Italian stone pines in the area and iii) analyze the climate-growth relationship of the Italian stone pine in the study area. The resulting Versiliana chronology was derived from 60 trees and spanned from 1828 to 2014 (187 years), representing one of the longest living Italian stone pine forests on the Italian Peninsula. Finally, the climate-growth analysis highlighted that at this site the latewood width is positively influenced by summer temperature, a peculiarity worthy of further investigations. 相似文献
97.
Nina Furnari 《Mammal Review》2013,43(4):323-326
Cavia intermedia, a rare species of cavy found exclusively on Moleques do Sul Island, Brazil, differs from other cavies in genetic and morphological characteristics and has been regarded as phylogenetically closest to Cavia magna. Here, I present morphological evidence for the likely origin of Cavia intermedia from an ancestor shared with Cavia magna: an external female genital organ similar in size and appearance to the male's penis. Masculinization of the female genitalia has been observed in Cavia magna but does not occur in Cavia aperea, which suggests a sister relationship between Cavia magna and Cavia intermedia. 相似文献
98.
George W. Barlow 《Environmental Biology of Fishes》1981,6(1):65-85
Synopsis Coral-reef fishes have been selected to produce propagules for dispersal because they live in a patchy environment, and the adults cannot migrate between patches. For large species (>100 mm SL) and widely separated patches, numerous propagules are needed, often with specialized pelagic intervals. Individuals of small species are confined to portions of the reef. They are unable to produce enough eggs for effective longrange dispersal, and so they keep their vulnerable eggs and young out of the plankton until they are well developed enough to seek out and settle onto the appropriate habitat before dispersing.Guarded demersal eggs, requiring a greater individual investment by the small short-lived species, further reduces their individual fecundity. These costs to fecundity, and the reduction in vagile young appear to account for the lack of postzygotic investment in larger longlived species.All coral-reef fishes are selected to disperse, usually with a young planktonic propagule interval. Both large and small species produce a mixed outcome, with some propagules returned to, or retained at the home reef, while others disperse more widely. The smaller the species the greater the proportion of propagules retained. 相似文献
99.
This study evaluated the sources, sinks, and factors controlling net export of nitrogen (N) from watersheds on the west coast
of the US. We calculated input of new N to 22 watersheds for 1992 and 2002. 1992 inputs ranged from 541 to 11,644 kg N km−2 year−1, with an overall area-weighted average of 1,870 kg N km−2 year−1. In 2002, the range of inputs was 490–10,875 kg N km−2 year−1, averaging 2,158 kg N km−2 year−1. Fertilizer was the most important source of new N, averaging 956 (1992) and 1,073 kg N km−2 year−1 (2002). Atmospheric deposition was the next most important input, averaging 833 (1992) and 717 kg N km−2 year−1 (2002), followed by biological N fixation in agricultural lands. Riverine N export, calculated based on measurements taken
at the furthest downstream USGS water quality monitoring station, averaged 165 (1992) and 196 kg N km−2 year−1 (2002), although data were available for only 7 watersheds at the latter time point. Downstream riverine N export was correlated
with variations in streamflow (export = 0.94 × streamflow − 5.65, R
2 = 0.66), with N inputs explaining an additional 16% of the variance (export = 1.06 × streamflow + 0.06 × input − 227.78,
R
2 = 0.82). The percentage of N input that is exported averaged 12%. Percent export was also related to streamflow (%export = 0.05 × streamflow − 2.61,
R
2 = 0.60). The correlations with streamflow are likely a result of its large dynamic range in these systems. However, the processes
that control watershed N export are not yet completely understood. 相似文献
100.