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991.
1. Bergmann's rule sensu lato, the ecogeographic pattern relating animals' body size with environmental temperature (or latitude), has been shown to be inconsistent among insect taxa. Body size clines remain largely unexplored in aquatic insects, which may show contrasting patterns to those found in terrestrial groups because of the physiological or mechanical constraints of the aquatic environment. 2. Bergmann's rule was tested using data on body size, phylogeny and distribution for 93 species belonging to four lineages of dytiscid water beetles. The relationship between size and latitude was explored at two taxonomic resolutions – within each independent lineage, and for the whole dataset – employing phylogenetic generalised least‐squares to control for phylogenetic inertia. The potential influence of habitat preference (lotic versus lentic) on body size clines was also considered. 3. Within‐lineage analyses showed negative relationships (i.e. converse Bergmann's rule), but only in two lineages (specifically in those that included both lotic and lentic species). By contrast, no relationship was found between body size and latitude for the whole dataset. 4. These results suggest that there may be no universal interspecific trends in latitudinal variation of body size in aquatic insects, even among closely related groups, and show the need to account for phylogenetic inertia. Furthermore, habitat preferences should be considered when exploring latitudinal clines in body size in aquatic taxa at the interspecific level.  相似文献   
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This paper estimates the costs to replace fish by protein from meat, from grains and legumes, or from dairy products. We apply the World Trade Model, an input–output model of the interactions among major world regions based on comparative advantage, to analyze alternative scenarios about protein content and sources in global diets. We find that the substitution of fish by meat or dairy entails several trillion U.S. dollars of additional costs annually, corresponding to increased use of pastureland, cropland, water, and other factors of production. The price of animal products increases steeply as higher‐cost producers need to come online, yielding rents to owners of scarce resources. By contrast, the global economy adjusts at significantly lower costs to the substitution of fish by grains and legumes, but this dietary shift involves substantial modification in the mix of agricultural output and its geographic distribution. There have been few analytic studies able to associate costs and prices directly with specific combinations of dietary options. We provide a flexible economic framework for analyzing alternative scenarios about the present and future production of food. The focus on the provision of protein for the human diet, allowing for substitutions between land‐based and aquatic sources, lays the groundwork for subsequent closer examinations of the potential future contribution of aquaculture and, in a yet broader framework, the impact of the coming generation of large dams on fish habitat and freshwater ecosystems more generally.  相似文献   
996.
We infer phylogenetic relationships within Teioidea, a superfamily of Nearctic and Neotropical lizards, using nucleotide sequences. Phylogenetic analyses relied on parsimony under tree‐alignment and similarity‐alignment, with length variation (i.e. gaps) treated as evidence and as absence of evidence, and maximum‐likelihood under similarity‐alignment with gaps as absence of evidence. All analyses produced almost completely resolved trees despite 86% of missing data. Tree‐alignment produced the shortest trees, the strict consensus of which is more similar to the maximum‐likelihood tree than to any of the other parsimony trees, in terms of both number of clades shared, parsimony cost and likelihood scores. Comparisons of tree costs suggest that the pattern of indels inferred by similarity‐alignment drove parsimony analyses on similarity‐aligned sequences away from more optimal solutions. All analyses agree in a majority of clades, although they differ from each other in unique ways, suggesting that neither the criterion of optimality, alignment nor treatment of indels alone can explain all differences. Parsimony rejects the monophyly of Gymnophthalmidae due to the position of Alopoglossinae relative to Teiidae, whereas support of Gymnophthalmidae by maximum‐likelihood was low. We address various nomenclatural issues, including Gymnophthalmidae Fitzinger, 1826 being an older name than Teiidae Gray, 1827. We recognize three families in the arrangement Alopoglossidae + (Teiidae + Gymnophthalmidae). Within Gymnophthalmidae we recognize Cercosaurinae, Gymnophthalminae, Rhachisaurinae and Riolaminae in the relationship Cercosaurinae + (Rhachisaurinae + (Riolaminae + Gymnophthalminae)). Cercosaurinae is composed of three tribes—Bachiini, Cercosaurini and Ecpleopodini—and Gymnophthalminae is composed of three—Gymnophthalmini, Heterodactylini and Iphisini. Within Teiidae we retain the currently recognized three subfamilies in the arrangement: Callopistinae + (Tupinambinae + Teiinae). We also propose several genus‐level changes to restore the monophyly of taxa.  相似文献   
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The evolution of the coleopteran suborder Adephaga is discussed based on a robust phylogenetic background. Analyses of morphological characters yield results nearly identical to recent molecular phylogenies, with the highly specialized Gyrinidae placed as sister to the remaining families, which form two large, reciprocally monophyletic subunits, the aquatic Haliplidae + Dytiscoidea (Meruidae, Noteridae, Aspidytidae, Amphizoidae, Hygrobiidae, Dytiscidae) on one hand, and the terrestrial Geadephaga (Trachypachidae + Carabidae) on the other. The ancestral habitat of Adephaga, either terrestrial or aquatic, remains ambiguous. The former option would imply two or three independent invasions of aquatic habitats, with very different structural adaptations in larvae of Gyrinidae, Haliplidae and Dytiscoidea.  相似文献   
999.
The bottlenose dolphin, genus Tursiops, is cosmopolitan occurring in tropical and temperate regions, with morphological variation between and within different oceans. Since the genus' taxonomy has been under discussion for a long time, this work aimed at analyzing the cranial variability of T. truncatus from different regions of the world. Geometric Morphometrics analyses were performed in 201 skulls of adult specimens, on dorsal, ventral, and lateral views, from the Eastern North Pacific, Eastern North Atlantic, Eastern South Atlantic, and Western South Atlantic oceans. The results indicate differences between individuals that inhabit the Atlantic and Pacific oceans. Within the Atlantic Ocean, there is an evident longitudinal differentiation of specimens from the eastern and western regions. A latitudinal separation was also observed, considering specimens from the North and South Atlantic Ocean. In the Western South Atlantic statistical differences were found between two morphological groups, identified as T. gephyreus (sensu Lahille, 1908) and T. truncatus, and the cross-validation presented 98% as minimum confidence for correct classification of these two groups. The present study provides strong morphological support to consider these two lineages as separate species.  相似文献   
1000.
The conifer family Cupressaceae encompasses seven subfamilies. Five of them were once considered to constitute the family Taxodiaceae, later eliminated because of its paraphyletic nature but remaining as an informal category for early-diverging Cupressaceae lineages. Among the taxodiaceous subfamilies, Athrotaxoideae shows a unique morphology in its ovuliferous complexes (OCs) and a phylogenetically unexplored fossil record. We describe the new genus and species Patagotaxodia lefipanensis, based on OC adpressions associated with leafy branches collected at the Maastrichtian section of the Lefipán Formation (Patagonia, Argentina), and we refer it to Athrotaxoideae. We include Patagotaxodia in total evidence phylogenetic analysis to test its affinity, and we recover it within the subfamilies Athrotaxoideae or Cunninghamioideae. However, we argue that the characters supporting the athrotaxoid affinity are more meaningful in a taxodiaceous systematic context. This placement is also supported by taxon inclusion-exclusion experiments. We discuss the position of other Cretaceous athrotaxoid records. With basis on the morphological insights provided by the OC morphology of extant and extinct Athrotaxoideae, we study the evolution of the OC morphology in the family in a phylogenetic context and discuss the results in the light of the fossil record of the family. We discuss how and when the different morphologies appeared in the family. Based on phylogenetic, temporal, morphological, and ontogenetic evidence, we conclude that the OC morphology shown by the subfamily Athrotaxoideae is intermediate between two of the most common morphologies within extant and extinct Cupressaceae species, one of which would show adaptative advantages over basal morphologies.  相似文献   
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