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Abstract The effects of gibberellic acid (GA3) on whole sunflower (Helianthus annuus L.) plants grown at three potassium (K) levels (0.0, 0.5 and 5.0 mM) were studied. A tenfold increase in the length of the first internode was observed when plants grown without K were treated with GA3. The uneven K distribution along the plant (higher K content in the higher internodes) was enhanced by GA3 treatment. Gibberellic acid increased the content of reducing sugars, especially in K-deficient plants. An increase in the K level in the nutrient solution resulted in a decrease of the osmotic potential of stem segments. Osmotic potential differences within the elongating first internode were increased by GA3 treatment. 相似文献
167.
MILAN CHVÁLA 《Systematic Entomology》1996,21(4):265-294
Abstract. The European species of the Hilara maura-group are revised. Three species are described as new to science, namely, H.nitidorella sp.n., H.discalis sp.n. (both temperate Central and Western Europe) and H.mauroides sp.n. (Caucasus, male only). A further five species, H.hybrida Collin, H.femorella Zetterstedt, H.sulcitarsis Strobl, H.tyrolensis Strobl and H.bartaki Straka are redescribed, and H.eumera Loew, 1873 becomes a new synonym of H.nitidula Zetterstedt, 1838. Seven lectotypes are designated. All IS European species are keyed, the main differential characters are illustrated, and additional data on biology and distribution are given. The Hilara maura-group is recognized as a monophyletic group within the genus, characterized by a set of apomorphous characters, and the hypothetical phylogenetic relationships of the species, classified into four natural complexes, are demonstrated. 相似文献
168.
Vestiges of an ancestral host plant: preference and performance in the butterfly Polygonia faunus and its sister species P. c‐album 下载免费PDF全文
SÖREN NYLIN LINA SÖDERLIND GABRIELLA GAMBERALE‐STILLE HÉLÈNE AUDUSSEAU MARIA DE LA PAZ CELORIO‐MANCERA NIKLAS JANZ FELIX A. H. SPERLING 《Ecological Entomology》2015,40(3):307-315
1. In the study of the evolution of insect–host plant interactions, important information is provided by host ranking correspondences among female preference, offspring preference, and offspring performance. Here, we contrast such patterns in two polyphagous sister species in the butterfly family Nymphalidae, the Nearctic Polygonia faunus, and the Palearctic P. c‐album. 2. These two species have similar host ranges, but according to the literature P. faunus does not use the ancestral host plant clade – the ‘urticalean rosids’. Comparisons of the species can thus test the effects of a change in insect–plant associations over a long time scale. Cage experiments confirmed that P. faunus females avoid laying eggs on Urtica dioica (the preferred host of P. c‐album), instead preferring Salix, Betula, and Ribes. 3. However, newly hatched larvae of both species readily accept and grow well on U. dioica, supporting the general theory that evolutionary changes in host range are initiated through shifts in female host preferences, whereas larvae are more conservative and also can retain the capacity to perform well on ancestral hosts over long time spans. 4. Similar rankings of host plants among female preference, offspring preference, and offspring performance were observed in P. c‐album but not in P. faunus. This is probably a result of vestiges of larval adaptations to the lost ancestral host taxon in the latter species. 5. Female and larval preferences seem to be largely free to evolve independently, and consequently larval preferences warrant more attention. 相似文献
169.
FOUAD SAYAH CLAIRE FAYET ANNE-MARIE LA VERDURE 《Invertebrate reproduction & development.》2013,57(2-3):269-275
Summary A polyclonal antibody raised against allatostatin-3 of Blattella germanica (BLAST-3) has been used to immunolocalize allatostatin-like peptides in the brain-retrocerebral complex of Labidura riparia adult females. Strongly stained immunoreactive cells are observed in the pars intercerebralis (14 cells) and mainly in the pars lateralis (32 cells). Fibres leading to the corpus allatum are also stained. In the deutocerebrum, one cell is immunostained at the root of each antennal nerve. In the tritocerebmm two cells in each brain hemisphere are weakly immunostained. During the reproductive cycle, these cells and their axons show immunoreactivity at previtellogenic, ovulation and ovarian arrest periods. During vitellogenesis, immunoreactivity is restricted to only four perikarya in the pars intercerebralis. When young vitellogenic females are injected with 20-hydroxyecdysone (20E), which inhibits vitellogenesis, full immunoreactivity reappears, suggesting sensibility of these cells to 20E as is expected for a negative feed-back loop (Sayah et al., 1995). These results show that BLAST-3-like material is produced periodically in Labidura in correlation with low levels of juvenile hormone and the absence of vitellogenesis. This study contributes to provide information on the degree of homology of allatostatins across various insects. 相似文献
170.
Germán Mariano Gasparini Sergio Gabriel Rodriguez Leopoldo Héctor Soibelzon Elisa Beilinson Esteban Soibelzon Rafaela Velloso Missagia 《Historical Biology》2013,25(6):785-800
Tayassu pecari is widely distributed across the Neotropical region, from northern Argentina to south-eastern Mexico. However, its fossil record is scarce; it is recorded since the middle Pleistocene to Holocene in Argentina, Brazil and Uruguay. This paper aims to: (1) update the systematic synonymy of this species; (2) review and update its geographic chronologic distribution and provide a new Lujanian record of Tayassu pecari in Buenos Aires Province and (3) discuss the paleoenvironmental and paleobiogeographical implications of this record. Considering the quantitative analysis performed, the fossil here recorded clearly integrates the group of Tayassu pecari. This specimen corresponds to the first record of Tayassu pecari in the central-northern region of the Buenos Aires Province. During Late Pleistocene, Tayassu pecari was distributed southern to its recent range, probably evidencing different paleoenvironment conditions. This species is the better adapted peccary to tropical and subtropical rainforests, but may also be present in arid environments. Consequently, Tayassu by itself is insufficient to infer the prevailing environmental conditions. However, according to the fauna associated with the specimen described here, it is possible to infer an open or semi-open and arid or semi-arid environment for the central-northern Buenos Aires region by Late Pleistocene times. 相似文献