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971.
Mariya A. Polyakova Iwona Dembicz Thomas Becker Ute Becker Olga N. Demina Nikolai Ermakov Goffredo Filibeck Riccardo Guarino Monika Janišová Renaud Jaunatre Łukasz Kozub Manuel J. Steinbauer Kohei Suzuki Jürgen Dengler 《Biodiversity and Conservation》2016,25(12):2251-2273
The drivers of plant richness at fine spatial scales in steppe ecosystems are still not sufficiently understood. Our main research questions were: (i) How rich in plant species are the natural steppes of Southern Siberia compared to natural and semi-natural grasslands in other regions of the Palaearctic? (ii) What are the main environmental drivers of the diversity patterns in these steppes? (iii) What are the diversity–environment relationships and do they vary between spatial scales and among different taxonomic groups? We sampled the steppe vegetation (vascular plants, bryophytes and lichens) in Khakassia (Russia) with 39 nested-plot series (0.0001–100-m2 plot size) and 54 additional 10-m2 quadrats across the regional range of steppe types and measured various environmental variables. We measured β-diversity using z-values of power-law species–area relationships. GLM analyses were performed to assess the importance of environmental variables as predictors of species richness and z-value. Khakassian steppes showed both high α- and β-diversity. We found significant scale dependence for the z-values, which had their highest values at small spatial scales and then decreased exponentially. Total species richness was controlled predominantly by heat load index, mean annual precipitation, humus content and soil skeleton content. The positive role of soil pH was evident only for vascular plant species richness. Similar to other studies, we found that the importance of environmental factors strongly differed among taxonomic groups and across spatial scales, thus highlighting the need to study more than one taxon and more than one plot size to get a reliable picture. 相似文献
972.
Life span extension by targeting a link between metabolism and histone acetylation in Drosophila
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973.
974.
Amaresh C. Panda Kotb Abdelmohsen Jennifer L. Martindale Clara Di?Germanio Xiaoling Yang Ioannis Grammatikakis Ji Heon Noh Yongqing Zhang Elin Lehrmann Dawood B. Dudekula Supriyo De Kevin G. Becker Elizabeth J. White Gerald M. Wilson Rafael de?Cabo Myriam Gorospe 《Nucleic acids research》2016,44(5):2393-2408
975.
Alessandra Becker Finco Ricardo Andrez Machado-de-Ávila Rayana Maciel Juliana De Moura Philippe Billiald Andrea Emilia Marques Stinghen Larissa M. Alvarenga 《Biochemistry and Biophysics Reports》2016
Advanced Glycation End Products (AGEs) are toxins that are involved in structural and functional alterations of several organs and tissues, resulting in various pathologies. Several types of AGEs have been described but carboxymethyllysine (CML) is the major antigenic AGE compound. In this study, three different immunogenic carrier proteins (KLH, keyhole limpet hemocyanin; BSA, bovine serum albumin; and HSA, human serum albumin) were modified by glycation. The glycated molecules were used to produce epitope-specific monoclonal antibodies able to recognize the CML domain and to detect uremic toxins in the serum of patients with chronic kidney disease (CKD). A competitive ELISA was standardized in order to quantify CML in the sera of CKD patients. An increase in uremic toxins can compromise the clinical condition of these patients, thus, the detection and quantification of these toxins should contribute to a better management and understanding of this disease. 相似文献
976.
Pavel V. Belichenko Rime Madani Lorianne Rey-Bellet Maria Pihlgren Ann Becker Adeline Plassard Stephanie Vuillermot Valérie Giriens Rachel L. Nosheny Alexander M. Kleschevnikov Janice S. Valletta Sara K. S. Bengtsson Gordon R. Linke Michael T. Maloney David T. Hickman Pedro Reis Anne Granet Dorin Mlaki Maria Pilar Lopez-Deber Long Do Nishant Singhal Eliezer Masliah Matthew L. Pearn Andrea Pfeifer Andreas Muhs William C. Mobley 《PloS one》2016,11(3)
In Down syndrome (DS) or trisomy of chromosome 21, the β-amyloid (Aβ) peptide product of the amyloid precursor protein (APP) is present in excess. Evidence points to increased APP gene dose and Aβ as playing a critical role in cognitive difficulties experienced by people with DS. Particularly, Aβ is linked to the late-life emergence of dementia as associated with neuropathological markers of Alzheimer’s disease (AD). At present, no treatment targets Aβ–related pathogenesis in people with DS. Herein we used a vaccine containing the Aβ 1–15 peptide embedded into liposomes together with the adjuvant monophosphoryl lipid A (MPLA). Ts65Dn mice, a model of DS, were immunized with the anti-Aβ vaccine at 5 months of age and were examined for cognitive measures at 8 months of age. The status of basal forebrain cholinergic neurons and brain levels of APP and its proteolytic products were measured. Immunization of Ts65Dn mice resulted in robust anti-Aβ IgG titers, demonstrating the ability of the vaccine to break self-tolerance. The vaccine-induced antibodies reacted with Aβ without detectable binding to either APP or its C-terminal fragments. Vaccination of Ts65Dn mice resulted in a modest, but non-significant reduction in brain Aβ levels relative to vehicle-treated Ts65Dn mice, resulting in similar levels of Aβ as diploid (2N) mice. Importantly, vaccinated Ts65Dn mice showed resolution of memory deficits in the novel object recognition and contextual fear conditioning tests, as well as reduction of cholinergic neuron atrophy. No treatment adverse effects were observed; vaccine did not result in inflammation, cellular infiltration, or hemorrhage. These data are the first to show that an anti-Aβ immunotherapeutic approach may act to target Aβ-related pathology in a mouse model of DS. 相似文献
977.
Background
Recent advances in obesity research suggest that BAT activity, or absence thereof, may be an important factor in the growing epidemic of obesity and its manifold complications. It is thus important to assess larger populations for BAT-activating and deactivating factors. 18FDG-PET/CT is the standard method to detect and quantify metabolic BAT activity, however, the manual measurement is not suitable for large studies due to its time-consuming nature and poor reproducibility across different software and devices.Methodology/Main Findings
In a retrospective study, 1060 consecutive scans of 1031 patients receiving a diagnostic 18FDG-PET/CT were examined for the presence of active BAT. Patients were classified according to a 3-tier system (supraclavicular, mediastinal, infradiaphragmatic) depending on the anatomical location of their active BAT depots, with the most caudal location being the decisive factor. The metabolic parameters (maximum activity, total volume and total glycolysis) were measured on a standard PET/CT workstation. Mean age of the population was 60±14.6y. 41.61% of patients were female. Metabolically active BAT was found in 53 patients (5.1%). Female, younger and leaner patients tended to have more active BAT, higher metabolic activity and more caudally active BAT. In total, 15 patients showed only supraclavicular, 27 additional mediastinal, and 11 infradiaphragmal activity. Interestingly, the activation of BAT always followed a cranio-caudal gradient. This anatomical pattern correlated with age and BMI as well as with all metabolic parameters, including maximum and total glycolysis (p<0.001).Conclusion
Based on our data we propose a simple method to grade or quantify the degree of BAT amount/activity in patients based on the most caudally activated depot. As new modalities for BAT visualization may arise in the future, this system would allow direct comparability with other modalities, in contrary to the PET-metrics, which are restricted to 18FDG-PET/CT. 相似文献978.
The conformation of the tridecapeptide alpha-factor of the yeast Saccharomyces cerevisiae was examined in both solution and in the presence of lipid vesicles. CD, differential scanning calorimetry, and phosphorus nmr all indicate that this mating pheromone interacts with lipid vesicles. In both aqueous and organic solution the alpha-factor is a flexible molecule that exhibits features of a type II beta-turn spanning the center of the peptide. Two-dimensional Nuclear Overhauser enhancement spectroscopy gives evidence that the beta-turn is stabilized on interaction of the peptide with lipid vesicles. Our current belief is that the beta-turn may play an important role in the biologically active conformation of the alpha-factor. 相似文献
979.
Becker A. B.; Hershkovich J.; Simons F. E.; Simons K. J.; Lilley M. K.; Kepron M. W. 《Journal of applied physiology》1989,66(6):2691-2697
We studied dogs neonatally sensitized to ragweed and their littermate controls at 4, 6, 8, 10, 12, and 15 mo of age. Acute allergic airway response to inhalation of ragweed in the sensitized dogs was marked (greater than 12-fold increase from base line) and reproducible at all times. Nonallergic airway responsiveness, measured as the concentration of acetylcholine required to increase airway resistance by 5 cmH2O.l-1.s (PC5), increased in sensitized and decreased in nonsensitized dogs from 4 to 15 mo of age (P less than 0.01). Before antigen, at 12 and 15 mo, sensitized dogs were significantly (P less than 0.05) more responsive to acetylcholine than controls. Six hours after antigen, sensitized dogs were 11-fold more responsive (P less than 0.005) than controls at those times. More eosinophils and mast cells and fewer macrophages (P less than 0.05) were present in bronchoalveolar lavage (BAL) from 12- and 15-mo-old sensitized dogs than their controls. BAL fluid histamine was higher (P less than 0.05) in sensitized than control dogs. Regression analysis revealed r = -0.75 (P = 0.003) between BAL mast cells and PC5 in sensitized dogs and R2 = 0.89 for PC5 and BAL mast cells, macrophages, and eosinophils. Neonatally sensitized dogs represent an excellent animal model in which to study the pathophysiology of asthma. 相似文献
980.
U V Mikel W F Engler E Perez-Rosario R L Becker I W McLean 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1989,11(2):111-114
Morphometric measurements of nucleoli were done on uveal melanomas from surviving and nonsurviving patients. The melanomas were embedded in paraffin and plastic, and measurement data from Papanicolaou-stained paraffin-embedded sections, toluidine blue-stained plastic-embedded sections and scanning transmission electron micrographs (STEM) of plastic-embedded sections were compared. The results showed that one parameter, the coefficient of variation (CV) of nucleolar area, correctly classified 80% of the cases as to survival when plastic-embedded material was used and 70% of the cases when paraffin-embedded material or STEM micrographs were used. The inverse standard deviation of the nucleolar area was a better predictor of outcome than was the CV of nucleolar area only in the paraffin-embedded sections. The nucleolar measurements were most easily and rapidly performed in the plastic-embedded sections. 相似文献