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Alvarez M Huygens D Díaz LM Villanueva CA Heyser W Boeckx P 《Plant, cell & environment》2012,35(1):126-135
Acid phosphatase (ACP) enzymes are involved in the mobilization of soil phosphorus (P) and polyphosphate accumulated in the fungal tissues of ectomycorrhizal roots, thereby influencing the amounts of P that are stored in the fungus and transferred to the host plant. This study evaluated the effects of ectomycorrhizal morphotype and soil fertility on ACP activity in the extraradical mycelium (ACP(myc)), the mantle (ACP(mantle)) and the Hartig net region (ACP(Hartig)) of ectomycorrhizal Nothofagus obliqua seedlings. ACP activity was quantified in vivo using enzyme-labelled fluorescence-97 (ELF-97) substrate, confocal laser microscopy and digital image processing routines. There was a significant effect of ectomycorrhizal morphotype on ACP(myc), ACP(mantle) and ACP(Hartig), while soil fertility had a significant effect on ACP(myc) and ACP(Hartig). The relative contribution of the mantle and the Hartig net region to the ACP activity on the ectomycorrhizal root was significantly affected by ectomycorrhizal morphotype and soil fertility. A positive correlation between ACP(Hartig) and the shoot P concentration was found, providing evidence that ACP activity at the fungus:root interface is involved in P transfer from the fungus to the host. It is concluded that the spatial distribution of ACP in ectomycorrhizas varies as a function of soil fertility and colonizing fungus. 相似文献
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Kevin Lambeets Frederik Hendrickx Stijn Vanacker Kris Van Looy Jean-Pierre Maelfait Dries Bonte 《Biodiversity and Conservation》2008,17(13):3133-3148
We assessed the composition of spider and carabid beetle assemblages along river banks from the Common Meuse (Belgium) to
determine their relationships with local topographical and landscape-related characteristics. Data were gathered with pitfall
traps in 1998 and explored by ordination and grouping methods. Our analysis revealed that the presence of xerothermic spider
species was limited to scarcely covered, less dynamic gravel banks. Riparian spider species were found on frequently flooded
as well as on rather elevated and high gravel banks, while riparian carabid beetles were dominant on all sampled banks. The
level of flooding disturbance, the vegetation density and the presence of silt appeared to be the most important environmental
determinants of spider and carabid beetle assemblage structure. Consequently, local environmental factors influence species
occurrence patterns in a similar way for the two investigated arthropod groups. Nevertheless, distinct ecological groups are
differently ordered along the prime environmental gradients. Nature management should therefore consider the conservation,
restoration and connectivity of both dynamic and more elevated banks in order to obtain a high degree of local and regional
heterogeneity throughout the river system. 相似文献
25.
H M Rajh J H Uitzetter L W Westerhuis C L van den Dries G I Tesser 《International journal of peptide and protein research》1979,14(1):68-79
In order to investigate the special function of tryptophan in peptide hormones, six tryptophan analogues have been synthesized, in which structural resemblance has been grossly retained and potentially essential properties have only partially been varied. The L-enantiomers have been isolated after enzymatic digestion of racemic dipeptide derivatives, and charge-transfer properties of the compounds have been studied. 相似文献
26.
Bram Dhondt Beatrijs Bossuyt Maurice Hoffmann Dries Bonte 《Basic and Applied Ecology》2008,9(5):542-549
The two-phase dispersal event in which dung beetles move seeds after endozoochory is often assumed to be advantageous for plant regeneration. Because seeds are expected to end up in favourable and safe germination sites, it is considered as an example of directed dispersal. However, literature so far is restricted to tropical rain forest ecosystems, while data for temperate regions are lacking. In this study, the effect of dung beetles on seedling establishment of endozoochorically dispersed seeds is evaluated for a temperate grassland ecosystem. We performed a field experiment in which cages excluded dung beetles from horse and cattle dung samples with mixed-in grass seeds. Seed germination from these samples was significantly higher than that from samples which were accessible to dung beetles. This indicates that the effect of dung beetles on short-term seedling establishment was negative, which contrasts with the patterns found for large-seeded species used in tropical studies. This is most likely attributed to the lack of roller species and the larger depth at which tunneling Geotrupes species bury seeds. 相似文献
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Monika Oláhová Wan Hee Yoon Kyle Thompson Sharayu Jangam Liliana Fernandez Jean M. Davidson Jennifer E. Kyle Megan E. Grove Dianna G. Fisk Jennefer N. Kohler Matthew Holmes Annika M. Dries Yong Huang Chunli Zhao Kévin Contrepois Zachary Zappala Laure Frésard Daryl Waggott Matthew T. Wheeler 《American journal of human genetics》2018,102(3):494-504
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C. G. E. van Noordwijk Hans Turin Theodoor Heijerman Kees Alders Peter Boer A. A. Mabelis Berend Aukema Aart Noordam Eva Remke Henk Siepel Matty P. Berg Dries Bonte 《Biodiversity and Conservation》2017,26(3):717-734
Conservation management is expected to increase local biodiversity, but uniform management may lead to biotic homogenization and diversity losses at the regional scale. We evaluated the effects of renewed grazing and cutting management carried out across a whole region, on the diversity of plants and seven arthropod groups. Changes in occurrence over 17 years of intensive calcareous grassland management were analysed at the species level, which gave insight into the exact species contributing to regional homogenization or differentiation. Reponses were compared between species differing in habitat affinity, dispersal ability, food specialisation and trophic level. Local species richness increased over the sampling period for true bugs and millipedes, while carabid beetles and weevils declined in local species richness. Species richness remained unchanged for plants, woodlice, ants and spiders. Regional diversity and compositional variation generally followed local patterns. Diversity shifts were only to a limited extent explained by species’ habitat affinity, dispersal ability, trophic level and food specialisation. We conclude that implementation of relatively uniform conservation management across a region did not lead to uniform changes in local species composition. This is an encouraging result for conservation managers, as it shows that there is not necessarily a conflict of interest between local and regional conservation goals. Our study also demonstrates that shifts in diversity patterns differ markedly between taxonomic groups. Single traits provide only limited understanding of these differences. This highlights the need for a wide taxonomic scope when evaluating conservation management and demonstrates the need to understand the mechanisms underlying occurrence shifts. 相似文献
30.
Camilla Wikenros Anders Jarnemo Marielle Frisén Dries P. J. Kuijper Krzysztof Schmidt 《Journal of Ethology》2017,35(2):161-168
Olfactory signals constitute an important mechanism in interspecific interactions, but little is known regarding their role in communication between predator species. We analyzed the behavioral responses of a mesopredator, the red fox (Vulpes vulpes), to an olfactory cue (scat) of an apex predator, the lynx (Lynx lynx) in Bia?owie?a Primeval Forest, Poland, using video camera traps. Red fox visited sites with scats more often than expected and the duration of their visits was longer at scat sites than at control sites (no scat added). Vigilant behavior, sniffing and scent marking (including over-marking) occurred more often at scat sites compared to control sites, where foxes mainly passed by. Vigilance was most pronounced during the first days of the recordings. Red fox behavior was also influenced by foxes previously visiting scat sites. They sniffed and scent marked (multiple over-marking) more frequently when the lynx scat had been over-marked previously by red fox. Fox visits to lynx scats may be seen as a trade-off between obtaining information on a potential food source (prey killed by lynx) and the potential risk of predation by an apex predator. 相似文献