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941.
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943.
Roberto Rivabene Alfredo Cantafora Chong Chao Yan Flavia Castellano Giovannella Bruscalupi Elena Bravo 《Bioscience reports》1992,12(5):425-432
The effects of HDL1 lipoprotein infusion on biliary lipid secretion were studied in thein vitro model of rat perfused liver. A strong increase in bile flow was observed during and after lipoprotein infusion. This caused a significant rise in cholesterol, phospholipid and bile salt secretions. However, only the percentage of cholesterol increased with respect to the other bile lipids. The changes observed in the cholesterol/phospholipid molar ratio values of liver membrane subfractions (i.e., liver plasma membrane, mitochondria plus lysosomes and microsomes) isolated from the perfused rat liver after HDL1 administration were not significant. 相似文献
944.
Carmela Calés Leticia Pavón Katarzyna Starowicz Claudia Pérez Mónica Bravo Tomokatsu Ikawa Haruhiko Koseki Miguel Vidal 《Molecular and cellular biology》2016,36(6):900-912
Polycomb chromatin modifiers regulate hematopoietic pluripotent stem and progenitor cell self-renewal and expansion. Polycomb complex redundancy and biochemical heterogeneity complicate the unraveling of the functional contributions of distinct components. We have studied the hematopoietic activity of RYBP, a direct interactor and proposed modulator of RING1A/RING1B-dependent histone H2A monoubiquitylation (H2AUb). Using a mouse model to conditionally inactivate Rybp in adult hematopoiesis, we have found that RYBP deletion results in a reversion of B-1-to-B-2 B-cell progenitor ratios, i.e., of the innate (predominantly fetal) to acquired (mostly adult) immunity precursors. Increased numbers of B-1 progenitors correlated with a loss of pre-proB cells, the B-2 progenitors. RYBP-deficient stem and progenitor cell populations (LKS) and isolated common lymphoid progenitors (CLP) gave rise to increased numbers of B-1 progenitors in vitro. Rybp inactivation, however, did not result in changes of global H2AUb and did not interact genetically with Ring1A or Ring1B deletions. These results show that a sustained regulation of the B-1-to-B-2 switch is needed throughout adult life and that RYBP plays an important role in keeping B-2 dominance, most likely independently of its Polycomb affiliation. 相似文献
945.
Richard E. Gibbons Javier Barrio Gustavo A. Bravo Luis Alza 《Journal of Field Ornithology》2011,82(4):355-365
ABSTRACT Estimating the geographic range of a species can be complicated by insufficient occurrence data and a lack of information about range limit determinants. Accurate estimates of species distributions are needed to assess the impacts of anthropogenic actions and for exploring evolutionary and ecological processes that maintain biological diversity. After documenting several extralimital locations for Black‐fronted Ground‐Tyrants (Muscisaxicola frontalis; Tyrannidae), we questioned the accuracy of the current winter range estimate. We provide specimen and observation records from central and southern Peru that represent new information about the winter distribution of Black‐fronted Ground‐Tyrants. We used ecological niche models generated from new extralimital records and records from the winter range to assess the current range estimate. We also tested winter and extralimital niche models for model equivalency using a resampling technique available through Maxent and ENM Tools. Niche models developed with locations from the winter range predicted with high probability (>90%) the area of the extralimital records. Reciprocally, niche models developed with the extralimital locations predicted the majority of the winter range locations, although the probability was lower for some locations and the most southerly points were not included in the prediction. The test for model equivalency did not distinguish the two models, suggesting the possibility that the extralimital records were from poorly sampled areas of the true winter range. Smaller scale habitat associations of Black‐fronted Ground‐Tyrants, such as a preference for sparsely vegetated slopes, were documented that were more specific than published accounts. Finally, we present the first case of frugivory in Muscisaxicola with the identification of Cumulopuntia boliviana ignescens (Cactaceae) seeds and pericarp in all five stomach samples of Black‐fronted Ground‐Tyrants collected in southern Peru. 相似文献
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947.
Here, we present a comprehensive phylogenetic analysis based on nuclear and mitochondrial DNA sequences of rodents of the subfamily Sigmodontinae. The emphasis is placed on the large tribe Phyllotini; sampling includes for the first time in any molecular‐based phylogenetic analysis representatives of several genera traditionally considered to be phyllotines. Given the broad taxonomic sampling, results provide substantial improvements in our knowledge on both the structure of the sigmodontine radiation and of phyllotine phylogenetic relationships. For instance, the tribe Ichthyomyini was not recovered monophyletic. Similarly, in a novel hypothesis on the contents of the tribe Phyllotini, it is shown that unlike Galenomys, the genera Chinchillula, Neotomys and Punomys are not phyllotines. The later genera together with Andinomys, Euneomys, Irenomys and Juliomys form part of novel generic clades of mostly Andean sigmodontine rodents. More in general, results strongly suggest the occurrence of several instances of putative morphological convergence among distinct sigmodontine lineages (e.g. among now considered to be ichthyomyines; between Phyllotini and some Andean taxa; among Euneomys‐Neotomys and Reithrodon). Finally, we suggest that the historical biogeography of the sigmodontine rodents is far more complex than earlier envisioned. 相似文献
948.
C. Hernández-Fuentes J. Galmés L. A. Bravo L. A. Cavieres 《Plant biology (Stuttgart, Germany)》2023,25(5):793-802
- We analysed whether Phacelia secunda populations from different elevations exhibit intrinsic traits associated with diffusive and biochemical components of photosynthesis, and if they differ in acclimation of photosynthesis to warmer temperatures. We hypothesized that P. secunda will have similar photosynthetic performance regardless of altitudinal provenance and that plants from high elevations will have a lower photosynthetic acclimation capacity to higher temperature than plants from low elevations.
- Plants from 1600, 2800 and 3600 m a.s.l. in the central Chilean Andes were collected and grown under two temperature regimes (20/16 °C and 30/26 °C day/night). The following photosynthetic traits were measured in each plant for the two temperature regimes: AN, gs, gm, Jmax, Vcmax, Rubisco carboxylation kcatc.
- Under a common growth environment, plants from the highest elevation had slightly lower CO2 assimilation rates compared to lower elevation plants. While diffusive components of photosynthesis increased with elevation provenance, the biochemical component decreased, suggesting compensation that explains the similar rates of photosynthesis among elevation provenances. Plants from high elevations had lower photosynthetic acclimation to warmer temperatures compared to plants from lower elevations, and these responses were related to elevational changes in diffusional and biochemical components of photosynthesis.
- Plants of P. secunda from different elevations maintain photosynthetic traits when grown in a common environment, suggesting low plasticity to respond to future climate changes. The fact that high elevation plants had lower photosynthetic acclimation to warmer temperature suggests higher susceptibility to increases in temperature associated with global warming.
949.
Freddy Bravo Hans Pohl Alberto Silva-Neto Rolf G. Beutel 《Cladistics : the international journal of the Willi Hennig Society》2009,25(6):614-623
An adult male of a newly discovered strepsipteran species from Brazil— Bahiaxenos relictus— is described. A new family Bahiaxenidae is suggested based on cladistic analyses of comprehensive morphological data sets with a broad taxon sampling including the stem group. It is unambiguously placed as the sister group of all other extant families of Strepsiptera. Bahiaxenos relictus is the only species of basal, i.e. non-stylopidian, Strepsiptera occurring in the New World. It appears to be a relict taxon that has survived in the fossil sand dunes of the São Francisco River (Bahia State). The loss of the 8th antennomere and the greatly reduced labrum are autapomorphies of Strepsiptera s.s . excluding Bahiaxenidae. The sister group relationship between†Protoxenidae and the remaining Strepsiptera, and between † Cretostylops and a clade comprising † Mengea and Strepsiptera s.s. , is confirmed, as is the monophyly of Stylopidia and Stylopiformia. 相似文献
950.