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31.
32.
R. Macdonald Ladell 《BMJ (Clinical research ed.)》1952,2(4792):1046-1047
33.
P. Macdonald Tow 《BMJ (Clinical research ed.)》1949,1(4597):285-286
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35.
Robie W. Macdonald 《人类与生态风险评估》2005,11(6):1099-1104
The Arctic faces threats from climate change and contaminants. Together, these two threats are likely to present surprises centered around the zero-degree isotherm because the phase change of water has enormous potential to affect contaminant transport and transfer, and biological distribution and stress. Particularly at risk are top aquatic predators, migratory species, and species narrowly adapted to ice. These species are most exposed to contaminants, are most likely to become stressed by climate change, or contain within their life cycles efficient vectors of contaminants and diseases. In the Arctic, mercury presents a special case where risks can be altered at many places in the biogeochemical cycle. Atmospheric mercury depletion events offer one such location; however, the methylation of mercury in aquatic systems appears a far more important and presently neglected component of risk from mercury to Arctic ecosystems. Climate variables alter transport, transfer, and capture of contaminants. Therefore, monitoring for contaminants must be conducted with a systems approach that includes climate-related factors. To ensure that the perception of risk is accurate and that priority risks are addressed first, a closer dialogue between scientists, the public, and public administers is urgently required. 相似文献
36.
Paul M. McNeill Ian H. Kerridge Catherine Arciuli David A. Henry Graham J. Macdonald Richard O. Day Suzanne R. Hill 《Journal of bioethical inquiry》2006,3(3):139-148
Aim To ascertain the quantity and nature of gifts and items provided by the pharmaceutical industry in Australia to medical specialists and to consider whether these are appropriate in terms of justifiable ethical standards, empirical research and views expressed in the literature.Design and Setting Fifty-one medical Sydney specialists were asked to collect all gifts, offers, invitations, and items received from pharmaceutical companies in an eight-week period.Main Outcome Measures The items received were categorised as promotional/educational, drug samples, clinical practice aids, office gifts, personal gifts, and invitations; and were analysed in relation to the pharmaceutical industry Code of Conduct.Results A large number (mean = 42/participant) and wide range of gifts and items were received. These included promotional/educational items (mean = 21), drug samples (mean = 8), office gifts (mean = 5) and personal gifts (mean = 1), clinical aids (mean = 3), and invitations (mean = 3) to meals, meetings, and conferences. Most gifts and items complied with the Code with a few breaches including offers of entertainment (sporting event and cabaret), items of high monetary value (in competitions with prizes unrelated to medicine), unbranded gifts, and promotional documents presented as journal articles.Conclusions Medical specialists received many gifts and items from pharmaceutical companies and a few that infringed the Code current at the time of the study. The findings were considered in the light of changes that have since been made to the industry Code of Conduct and professional medical guidelines on ethical relationships between physicians and the industry. In large measure, these changes are supported although some suggestions are made for stricter standards.Competing Interest Graham Macdonald is employed by Merck Sharp & Dohme (Australia). Richard Day serves as an Advisory Board member for Merck Sharp & Dohme (Australia) (rofecoxib, etoricoxib), Merck Sharp & Dohme (Asia) (rofecoxib), Abbott Australia (adalimumab), Schering–Plough Australia (infliximab), Amgen Australia (anakinra), GlaxoSmithKline Consumer Australia (paracetamol) and, previously, Pfizer Australia (celecoxib). Any honoraria for these activities are placed in audited trust funds of St Vincent’s Hospital, Sydney, to be used to support academic activities within the Department of Clinical Pharmacology. 相似文献
37.
Laura A. Onyango R. Hugh Dunstan Timothy K. Roberts Margaret M. Macdonald Johan Gottfries 《PloS one》2013,8(10)
This study investigated whether alterations in environmental conditions would induce the formation of small colony variant phenotypes (SCV) with associated changes in cell morphology and ultra-structure in S. aureus, s. epidermidis, and S. lugdunensis. Wild-type clinical isolates were exposed to low temperature (4°C), antibiotic stress (penicillin G and vancomycin; 0-10,000 µg mL-1), pH stress (pH 3-9) and osmotic challenge (NaCl concentrations of 0-20%). Changes in cell diameter, cell-wall thickness, and population distribution changes (n ≥ 300) were assessed via scanning and transmission electron microscopy (SEM and TEM), and compared to control populations. Our analyses found that prolonged exposure to all treatments resulted in the subsequent formation of SCV phenotypes. Observed SCVs manifested as minute colonies with reduced haemolysis and pigmentation (NaCl, pH and 4°C treatments), or complete lack thereof (antibiotic treatments). SEM comparison analyses revealed significantly smaller cell sizes for SCV populations except in S. aureus and S. epidermidis 10% NaCl, and S. epidermidis 4°C (p<0.05). Shifts in population distribution patterns were also observed with distinct sub-populations of smaller cells appearing for S. epidermidis, and S. lugdunensis. TEM analyses revealed significantly thicker cell-walls in all treatments and species except S. lugdunensis exposed to 4°C. These findings suggest that staphylococci adapted to environmental stresses by altering their cell size and wall thickness which could represent the formation of altered phenotypes which facilitate survival under harsh conditions. The phenotypic response was governed by the type of prevailing environmental stress regime leading to appropriate alterations in ultra-structure and size, suggesting downstream changes in gene expression, the proteome, and metabolome. 相似文献
38.
Zeke Davidson Marion Valeix Freya Van Kesteren Andrew J. Loveridge Jane E. Hunt Felix Murindagomo David W. Macdonald 《PloS one》2013,8(2)
Large carnivores inhabiting ecosystems with heterogeneously distributed environmental resources with strong seasonal variations frequently employ opportunistic foraging strategies, often typified by seasonal switches in diet. In semi-arid ecosystems, herbivore distribution is generally more homogeneous in the wet season, when surface water is abundant, than in the dry season when only permanent sources remain. Here, we investigate the seasonal contribution of the different herbivore species, prey preference and distribution of kills (i.e. feeding locations) of African lions in Hwange National Park, Zimbabwe, a semi-arid African savanna structured by artificial waterholes. We used data from 245 kills and 74 faecal samples. Buffalo consistently emerged as the most frequently utilised prey in all seasons by both male (56%) and female (33%) lions, contributing the most to lion dietary biomass. Jacobs’ index also revealed that buffalo was the most intensively selected species throughout the year. For female lions, kudu and to a lesser extent the group “medium Bovidae” are the most important secondary prey. This study revealed seasonal patterns in secondary prey consumption by female lions partly based on prey ecology with browsers, such as giraffe and kudu, mainly consumed in the early dry season, and grazers, such as zebra and suids, contributing more to female diet in the late dry season. Further, it revealed the opportunistic hunting behaviour of lions for prey as diverse as elephants and mice, with elephants taken mostly as juveniles at the end of the dry season during droughts. Jacobs’ index finally revealed a very strong preference for kills within 2 km from a waterhole for all prey species, except small antelopes, in all seasons. This suggested that surface-water resources form passive traps and contribute to the structuring of lion foraging behaviour. 相似文献
39.
David N. Juurlink Colin R. Dormuth Anjie Huang Chelsea Hellings J. Michael Paterson Colette Raymond Anita Kozyrskyj Yola Moride Erin M. Macdonald Muhammad M. Mamdani 《PloS one》2013,8(12)
Background
Recent evidence suggests that proton pump inhibitors (PPIs) might be linked with adverse cardiac events, but a causal relationship is unproven.Methods
We applied the self-matched case series method to two studies using population-based health care data from Ontario, Canada between 1996 and 2008. The first included subjects aged 66 years or older hospitalized for acute myocardial infarction within 12 weeks following initiation of PPI, while the second included subjects hospitalized for heart failure. In both studies we designated the primary risk interval as the initial 4 weeks of therapy and the control interval as the final 4 weeks. To test the specificity of our findings we examined use of histamine H2 receptor antagonists and benzodiazepines, drugs with no plausible causal link to adverse cardiac events.Results
During the 13-year study period, we identified 5550 hospital admissions for acute myocardial infarction and 6003 admissions for heart failure within 12 weeks of commencing PPI therapy. In the main analyses, we found that initiation of a PPI was associated with a higher risk of acute myocardial infarction (odds ratio 1.8; 95% confidence interval 1.7 to 1.9) and heart failure (odds ratio 1.8; 95% confidence interval 1.7 to 1.9). However, secondary analyses revealed similar risk estimates histamine H2 receptor antagonists and benzodiazepines, drugs with no known or suspected association with adverse cardiac events.Conclusion
PPIs are associated with a short-term risk of adverse cardiac events, but similar associations are seen with other drugs exhibiting no known cardiac toxicity. Collectively these observations suggest that the association between PPIs and adverse cardiac events does not represent reflect cause-and-effect. 相似文献40.
Emily Banks Grace Joshy Walter P. Abhayaratna Leonard Kritharides Peter S. Macdonald Rosemary J. Korda John P. Chalmers 《PLoS medicine》2013,10(1)