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991.
Eddy covariance captures four‐phase crassulacean acid metabolism (CAM) gas exchange signature in Agave 下载免费PDF全文
Nick A. Owen Órlaith Ní Choncubhair Jamie Males José Ignacio del Real Laborde Ramón Rubio‐Cortés Howard Griffiths Gary Lanigan 《Plant, cell & environment》2016,39(2):295-309
Mass and energy fluxes were measured over a field of Agave tequilana in Mexico using eddy covariance (EC) methodology. Data were gathered over 252 d, including the transition from wet to dry periods. Net ecosystem exchanges (FN,EC) displayed a crassulacean acid metabolism (CAM) rhythm that alternated from CO2 sink at night to CO2 source during the day, and partitioned canopy fluxes (FA,EC) showed a characteristic four‐phase CO2 exchange pattern. Results were cross‐validated against diel changes in titratable acidity, leaf‐unfurling rates, energy exchange fluxes and reported biomass yields. Projected carbon balance (g C m?2 year?1, mean ± 95% confidence interval) indicated the site was a net sink of ?333 ± 24, of which contributions from soil respiration were +692 ± 7, and FA,EC was ?1025 ± 25. EC estimated biomass yield was 20.1 Mg (dry) ha?1 year?1. Average integrated daily FA,EC was ?234 ± 5 mmol CO2 m?2 d?1 and persisted almost unchanged after 70 d of drought conditions. Regression analyses were performed on the EC data to identify the best environmental predictors of FA. Results suggest that the carbon acquisition strategy of Agave offers productivity and drought resilience advantages over conventional semi‐arid C3 and C4 bioenergy candidates. 相似文献
992.
Postnatal development of franciscana's (Pontoporia blainvillei) biosonar relevant structures with potential implications for function,life history,and bycatch 下载免费PDF全文
Guilherme Frainer Stefan Huggenberger Ignacio Benites Moreno 《Marine Mammal Science》2015,31(3):1193-1212
Franciscana dolphins (Pontoporia blainvillei) are the most endangered species of the western South Atlantic Ocean. The major cause of their vulnerability is incidental bycatch in fishery gill nets. Ontogenetic changes of biosonar relevant structures in Pontoporia were analyzed in five specimens (one female neonate, two male neonates and two male adults) using digital imaging technology (MRI, CT) and macroscopic dissections to compare structures involved in sound production and reception. These data were compared to an ontogenetic series of 69 macerated skulls of Pontoporia in order to elucidate the correlation between soft tissue structures and bones of the epicranial complex and to describe the development‐related changes in the mandible. Postnatal developmental shape changes of the posterior part of the right vestibular air sac followed bone formation and the melon with its right branch elongated, paralleling the flatter facial depression of adults. Minor postnatal developmental modifications were verified in the tympano‐periotic complex but a shape change of the mandible was visible by a ventral deviation of the posterior part of the mandible in adults. These results reveal postnatal changes in allometry and shape of biosonar relevant structures that may be one of the causes that increase bycatch of neonate and young Pontoporia individuals. 相似文献
993.
Andrés N. Grasso Virginia Goldberg Elly A. Navajas Wanda Iriarte Diego Gimeno Ignacio Aguilar Juan F. Medrano Gonzalo Rincón Gabriel Ciappesoni 《Genetics and molecular biology》2014,37(2):389-395
The aim of this study was to investigate the genetic diversity within and among three breeds of sheep: Corriedale, Merino and Creole. Sheep from the three breeds (Merino n = 110, Corriedale n = 108 and Creole n = 10) were genotyped using the Illumina Ovine SNP50 beadchip®. Genetic diversity was evaluated by comparing the minor allele frequency (MAF) among breeds. Population structure and genetic differentiation were assessed using STRUCTURE software, principal component analysis (PCA) and fixation index (FST). Fixed markers (MAF = 0) that were different among breeds were identified as specific breed markers. Using a subset of 18,181 single nucleotide polymorphisms (SNPs), PCA and STUCTURE analysis were able to explain population stratification within breeds. Merino and Corriedale divergent lines showed high levels of polymorphism (89.4% and 86% of polymorphic SNPs, respectively) and moderate genetic differentiation (FST = 0.08) between them. In contrast, Creole had only 69% polymorphic SNPs and showed greater genetic differentiation from the other two breeds (FST = 0.17 for both breeds). Hence, a subset of molecular markers present in the OvineSNP50 is informative enough for breed assignment and population structure analysis of commercial and Creole breeds. 相似文献
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996.
Manuel M. Valdivia Jesús Avila Javier Coll Camilo Colaço Ignacio V. Sandoval 《Biochemical and biophysical research communications》1982,105(4):1241-1249
A radioimmunoassay developed for the microtubule associated protein MAP2 shows that this protein, or related polypeptides are present in all the porcine tissues studied. Nervous tissues (brain, 11 μg MAP2/mg protein; cerebellum, 9.7 μg MAP2/mg protein) contain much higher levels of MAP2 than non-nervous tissues (kidney, 104 ng MAP2/mg protein; lung 89 ng MAP2/mg protein; spleen 66 ng MAP2/mg protein; thyroid 21 ng MAP2/mg protein; liver 9.7 ng MAP2/mg protein). A heat resistant protein doublet of 300,000 with the ability to promote microtubule polymerization has been purified from pig kidney cells by affinity chromatography using MAP2 antibodies. Using a similar purification method a protein of 200,000 daltons has been isolated from Hela cells. 相似文献
997.
Growth-Dependent Stable Carbon Isotope Fractionation by Basidiomycete Fungi: δ13C Pattern and Physiological Process 下载免费PDF全文
We grew 11 basidiomycetes in axenic culture to characterize their physiological capacities to fractionate stable C isotopes. Generally, δ13C values of the fungal biomass were (i) enriched in 13C relative to the growth medium, (ii) variable among the isolates, and (iii) dependent on the growth rate and growth stage of the fungi. We found a multiphasic dynamic of fractionation for Cryptoporus volvatus and Marasmius androsaceus during various growth stages. The first phase, P1, corresponded to the exponential growth stage and was characterized by an increasing enrichment in 13C content of the fungal biomass relative to the growth medium ranging between 4.6 and 6.9‰. The second phase, P2, exhibited a continual depletion in 13C of the fungal biomass, with the δ13C values of the fungal biomass asymptotically returning to the δ13C value of the growth medium at inoculation. The expression of the various fractionation phases was dependent on the amount of low-concentration micronutrients and growth factors added to the growth medium. The onset of P2 occurred at reduced concentrations of these elements. All of the sugars in the growth medium (sucrose, maltose, and glucose) were utilized for growth, indicating that the observed fractionation was not an artifact derived from the preferential use of 13C-rich maltose, which was found at low concentrations in the growth medium. In this study, we establish a framework with which to explore the impact of physiological fractionations by fungal interfaces on natural distributions of stable C isotopes. 相似文献
998.
The relative contributions of sexual reproduction and clonal propagation in Opuntia rastrera from two habitats in the Chihuahuan Desert 总被引:2,自引:0,他引:2
María Del Carmen Mandujano Carlos Montan† Ignacio Méndez‡ Jordan Golubov 《Journal of Ecology》1998,86(6):911-921
1 The clonal cactus Opuntia rastrera shows predominantly sexual reproduction in grasslands (GH) and clonal propagation in nopaleras (NH). We assessed the effects of light, herbivory, water availability and the habitat an offspring came from on the survival and growth of sexual or clonal offspring (i.e. seedlings and cladodes), through 3- and 4-year common garden and short-term greenhouse experiments.
2 Shading by nurse plants increased seedling survival in the field by an order of magnitude, and a small additional advantage due to predator protection by grasses was observed. Strong herbivory transforms a facultative nurse–protégé relationship for seedlings into an obligatory one.
3 In the greenhouse seedlings grew better under shade, but in the field the production of the first cladode was delayed in seedlings in the more shaded GH. Competition for soil resources may be more intense under a dense grass tussock than under a open shrub, thus affecting the nurse–protégé relationship. Seedling survival under nurse plants was similar in GH and NH, but higher plant cover suggests that a larger number of seedlings will establish in GH in the long term.
4 Cladode survival was higher in NH. Cladodes were more successful than seedlings at establishing in intercanopy areas, possibly due to physiological differences as well as their ability to survive partial predation. Cladode survival in intercanopy areas may explain the enhanced clonal propagation in the more open NH scrubland, together with their susceptibility to the flooding which affects GH.
5 The high seedling and cladode survival in the greenhouse experiments contrasted with that observed in the field, indicating that survival is determined by the interaction between herbivores, plants and abiotic conditions rather than the physiological aptitude of the plants. 相似文献
2 Shading by nurse plants increased seedling survival in the field by an order of magnitude, and a small additional advantage due to predator protection by grasses was observed. Strong herbivory transforms a facultative nurse–protégé relationship for seedlings into an obligatory one.
3 In the greenhouse seedlings grew better under shade, but in the field the production of the first cladode was delayed in seedlings in the more shaded GH. Competition for soil resources may be more intense under a dense grass tussock than under a open shrub, thus affecting the nurse–protégé relationship. Seedling survival under nurse plants was similar in GH and NH, but higher plant cover suggests that a larger number of seedlings will establish in GH in the long term.
4 Cladode survival was higher in NH. Cladodes were more successful than seedlings at establishing in intercanopy areas, possibly due to physiological differences as well as their ability to survive partial predation. Cladode survival in intercanopy areas may explain the enhanced clonal propagation in the more open NH scrubland, together with their susceptibility to the flooding which affects GH.
5 The high seedling and cladode survival in the greenhouse experiments contrasted with that observed in the field, indicating that survival is determined by the interaction between herbivores, plants and abiotic conditions rather than the physiological aptitude of the plants. 相似文献
999.
Machado Alberto Nuñez de Castro Ignacio Mayor Federico 《Molecular and cellular biochemistry》1975,6(2):93-100
Molecular and Cellular Biochemistry - The activities of isocitrate dehydrogenase (NAD), isocitrate dehydrogenase (NADP) and oxoglutarate dehydrogenase have been investigated inSaccharomyces... 相似文献
1000.
The effect of the oxygen supply on growth, water absorptionof cells and cell wall changes was studied in coleoptiles ofrice seedlings growing under three different conditions: underwater, under water with constant air bubbling and in air. Coleoptilegrowth was larger when they were grown under water than in waterwith air bubbling and in air. Coleoptile growth under waterwas limited by the suction force of their cells rather thanby mechanical properties of the cell wall, while that of thecoleoptiles growing under the other two conditions was limitedby the cell wall rigidity. A decrease in the relative amountof noncellulosic glucose of the cell wall, and an increase inthe noncellulosic xylose during coleoptile growth were foundfor all three culture conditions.
1 Present address: Departamento de Fisiologia Vegetal, Facultadde Ciencias, Universidad, Salamanca, Spain. (Received May 21, 1979; ) 相似文献