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171.
Measurements on the growth process and placental development of the embryo and fetuses of Cavia porcellus were carried out using ultrasonography. Embryo, fetus, and placenta were monitored from Day 15 after mating day to the end of gestation. Based on linear and quadratic regressions, the following morphometric analysis showed a good indicator of the gestational age: placental diameter, biparietal diameter, renal length, and crown rump. The embryonic cardiac beat was first detected at an average of 22.5 days. The placental diameter showed constant increase from beginning of gestation then remained to term and presented a quadratic correlation with gestational age (r2 = 0.89). Mean placental diameter at the end of pregnancy was 3.5 ± 0.23 cm. By Day 30, it was possible to measure biparietal diameter, which followed a linear pattern of increase up to the end of gestation (r2 = 0.95). Mean biparietal diameter in the end of pregnancy was 1.94 ± 0.03 cm. Kidneys were firstly observed on Day 35 as hyperechoic structures without the distinction of medullar and cortical layers, thus the regression model equation between kidney length and gestational age presents a quadratic relationship (r2 = 0.7). The crown rump presented a simple linear growth, starting from 15 days of gestation, displaying a high correlation with the gestational age (r2 = 0.9). The offspring were born after an average gestation of 61.3 days. In this study, we conclude that biparietal diameter, placental diameter, and crown rump are adequate predictive parameters of gestational age in guinea pigs because they present high correlation index. 相似文献
172.
173.
Biogeographical variation in the population density of wild boar (Sus scrofa) in western Eurasia 总被引:1,自引:0,他引:1
Claudia Melis Paulina A. Szafraska Bogumia Jdrzejewska Kamil Barto 《Journal of Biogeography》2006,33(5):803-811
Aim We reviewed 54 studies reporting population densities of wild boar (Sus scrofa) in western Eurasia in order to investigate the roles of vegetation productivity [fraction of photosynthetically active radiation (FPAR) index], winter harshness (mean January temperature) and presence/absence of wolves (Canis lupus) in shaping the biogeographical variation in population density of wild boar. Location We collected published data on the autumn–winter population density of wild boar (number of individuals km?2) in 54 locations in western Eurasia, from 1966 to 2003. Methods The mean January temperature, obtained from the World Climate data base ( http://www.worldclimate.com ), was taken as a measure of winter severity. We used monthly 4 × 4 km MODIS FPAR data sets covering January 2000 to June 2004 to calculate the vegetation productivity index. In addition, we collected literature data about the presence or absence of wolves from the study areas. Results In the geographical span of 37–60° N, the population densities of wild boar declined by three orders of magnitude, from 10 to 0.01 individuals km?2. The best multiple regression model (selected with the Akaike information criterion corrected for small samples) showed that mean January temperature and the vegetation productivity index were the most important factors explaining the biogeographical variation in population densities of wild boar. The impact of temperature was stronger than that of productivity. The presence of wolves had a weak limiting effect on population densities of wild boar at the biogeographical scale. Main conclusion We propose that winter harshness imposes density‐independent mortality on wild boar populations at higher latitudes. Competition for food in less productive regions may cause stronger density dependence in birth and death rates of wild boar populations. We expect that wild boar will respond to global warming by both an increase in local population densities and an expansion of their geographical range north and north‐eastwards. 相似文献
174.
Diana E. Wetzler Mariana Gallo Riccardo Melis Tomasso Eliseo Alejandro D. Nadra Diego U. Ferreiro Maurizio Paci Ignacio E. Sánchez Daniel O. Cicero Gonzalo de Prat Gay 《Biopolymers》2009,91(6):432-443
Nucleic acid recognition is often mediated by α‐helices or disordered regions that fold into α‐helix on binding. A peptide bearing the DNA recognition helix of HPV16 E2 displays type II polyproline (PII) structure as judged by pH, temperature, and solvent effects on the CD spectra. NMR experiments indicate that the canonical α‐helix is stabilized at the N‐terminus, while the PII forms at the C‐terminus half of the peptide. Re‐examination of the dihedral angles of the DNA binding helix in the crystal structure and analysis of the NMR chemical shift indexes confirm that the N‐terminus half is a canonical α‐helix, while the C‐terminal half adopts a 310 helix structure. These regions precisely match two locally driven folding nucleii, which partake in the native hydrophobic core and modulate a conformational switch in the DNA binding helix. The peptide shows only weak and unspecific residual DNA binding, 104‐fold lower affinity, and 500‐fold lower discrimination capacity compared with the domain. Thus, the precise side chain conformation required for modulated and tight physiological binding by HPV E2 is largely determined by the noncanonical strained α‐helix conformation, “presented” by this unique architecture. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 432–443, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com 相似文献
175.
Aurora kinase A (AURKA) is a conserved kinase that plays crucial roles in numerous cellular processes. Although AURKA overexpression is frequent in human cancers, its pleiotropic functions and multifaceted regulation present challenges in its therapeutic targeting. Key to overcoming these challenges is to identify and characterize the full range of AURKA interactors, which are often weak and transient. Previous proteomic studies were limited in monitoring dynamic and non‐mitotic AURKA interactions. Here, we generate the proximity interactome of AURKA in asynchronous cells, which consists of 440 proteins involving multiple biological processes and cellular compartments. Importantly, AURKA has extensive proximate and physical interactions to centriolar satellites, key regulators of the primary cilium. Loss‐of‐function experiments identify satellites as negative regulators of AURKA activity, abundance, and localization in quiescent cells. Notably, loss of satellites activates AURKA at the basal body, decreases centrosomal IFT88 levels, and causes ciliogenesis defects. Collectively, our results provide a resource for dissecting spatiotemporal regulation of AURKA and uncover its proteostatic regulation by satellites as a new mechanism for its ciliary functions. 相似文献
176.
Claudia Melis Ivar Herfindal Kaarina Kauhala Reidar Andersen Kjell-Arild Høgda 《Mammalian Biology》2010,75(2):151-159
Annual variation in the environment is expected to influence individual performance, e.g. measured as body condition, such as body mass or fat deposition, through its direct or indirect effects on food abundance and availability. Such environmental variation is traditionally measured by climatic observation, but recently, measures of environmental phenology obtained from satellite images have been successfully used. We examined the performance of climatic and plant phenology variables in explaining body condition of an invasive omnivore species: the raccoon dog Nyctereutes procyonoides. We collected data on fat deposition of juveniles in southern Finland from the end of June to the beginning of November. A four-parametric logistic model was fitted separately for each province to the data by non-linear regression procedure and the residuals were compared to the expected average as measure of individual performance. These values were then analysed with respect to the environmental variables. Climatic variables describing spring conditions performed better than plant phenology variables in explaining the variation in fat deposition. Harsh spring conditions negatively affected the amount of fat deposed during the growing season. Plant phenology variables, effective in explaining life history traits in herbivores, might not reflect variation in food abundance and quality for omnivore species. We propose that in Europe raccoon dogs will benefit from climate warming, because of a longer growing season, but increased spring precipitation in the form of snow at higher latitudes might compensate for the effect of greater primary productivity and outline the border of their expansion towards harsher environments. 相似文献
177.
Nora Lemke Valeria Melis Dilyara Lauer Mandy Magbagbeolu Boris Neumann Charles R. Harrington Gernot Riedel Claude M. Wischik Franz Theuring Karima Schwab 《The Journal of biological chemistry》2020,295(52):18508
Synapse loss is associated with motor and cognitive decline in multiple neurodegenerative disorders, and the cellular redistribution of tau is related to synaptic impairment in tauopathies, such as Alzheimer''s disease and frontotemporal dementia. Here, we examined the cellular distribution of tau protein species in human tau overexpressing line 66 mice, a transgenic mouse model akin to genetic variants of frontotemporal dementia. Line 66 mice express intracellular tau aggregates in multiple brain regions and exhibit sensorimotor and motor learning deficiencies. Using a series of anti-tau antibodies, we observed, histologically, that nonphosphorylated transgenic human tau is enriched in synapses, whereas phosphorylated tau accumulates predominantly in cell bodies and axons. Subcellular fractionation confirmed that human tau is highly enriched in insoluble cytosolic and synaptosomal fractions, whereas endogenous mouse tau is virtually absent from synapses. Cytosolic tau was resistant to solubilization with urea and Triton X-100, indicating the formation of larger tau aggregates. By contrast, synaptic tau was partially soluble after Triton X-100 treatment and most likely represents aggregates of smaller size. MS corroborated that synaptosomal tau is nonphosphorylated. Tau enriched in the synapse of line 66 mice, therefore, appears to be in an oligomeric and nonphosphorylated state, and one that could have a direct impact on cognitive function. 相似文献
178.
Denise T. G. Bizuti Thaís de Marchi Soares Marina M. Duarte Jos C. Casagrande Vanessa de Souza Moreno Francisco J. M. Peinado Simone D. Sartorio de Medeiros Juliano van Melis Daniella Schweizer Pedro H. S. Brancalion 《Restoration Ecology》2020,28(5):1237-1246
Soil phosphorus (P) is a major driver of forest development and a critically limited nutrient in tropical soils, especially when topsoil is removed by mining. This nutrient can be present in soils in the form of different fractions, which have direct consequences for P availability to plants and, consequently, for restoration success. Therefore, understanding how the stocks of different soil P fractions change over the restoration process can be essential for guiding restoration interventions, monitoring, and adaptive management. Here, we investigated the recovery of soil P fractions by forest restoration interventions on bauxite mine sites in the Brazilian Atlantic Forest. We assessed the concentration of different fractions of soil organic and inorganic P at (1) a bauxite mine prepared for restoration; (2) two former bauxite mines undergoing forest restoration for 6 and 24 years; and (3) an old‐growth forest remnant. Overall, restored areas recovered levels of labile organic P (Po‐NaHCO3) at 5–40 cm and of moderately labile organic P (Po‐NaOH) at different depths, exhibiting concentrations similar to those found in a conserved forest. The use of P‐rich fertilizers and forest topsoil may have greatly contributed to this outcome. Some other fractions, however, recovered only after 24 years of restoration. Other inorganic P fractions did not differ among mined, restored, and conserved sites: nonlabile Pi (residual P and P‐HCl), labile Pi (Pi‐NaHCO3), and moderately labile Pi (Pi‐NaOH). Forest restoration was able to promote efficient recovery of important soil P fractions, highlighting the value of restoration efforts to mitigate soil degradation by mining. 相似文献
179.
Plasmonics - Hexagonal boron nitrides (hBNs) are promising nanomaterials with their high boron content, non-toxic nature in inactive form, high chemical stability, and mechanical strength. However,... 相似文献
180.
Valsami Eleftheria-Angeliki Pateraki Angeliki Melis Anastasios Ghanotakis Demetrios F. 《Journal of applied phycology》2021,33(4):2157-2168
Journal of Applied Phycology - The aim of the present work was the investigation of various cultivation conditions in order to provide a foundation for a sustainable, financially viable, and... 相似文献