首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2812篇
  免费   207篇
  国内免费   40篇
耳鼻咽喉   8篇
儿科学   127篇
妇产科学   65篇
基础医学   279篇
口腔科学   50篇
临床医学   606篇
内科学   405篇
皮肤病学   25篇
神经病学   205篇
特种医学   240篇
外科学   234篇
综合类   51篇
预防医学   197篇
眼科学   159篇
药学   302篇
中国医学   2篇
肿瘤学   104篇
  2021年   24篇
  2019年   38篇
  2018年   40篇
  2017年   20篇
  2016年   32篇
  2015年   46篇
  2014年   46篇
  2013年   89篇
  2012年   91篇
  2011年   92篇
  2010年   61篇
  2009年   79篇
  2008年   93篇
  2007年   93篇
  2006年   94篇
  2005年   86篇
  2004年   103篇
  2003年   97篇
  2002年   73篇
  2001年   85篇
  2000年   82篇
  1999年   101篇
  1998年   114篇
  1997年   109篇
  1996年   106篇
  1995年   84篇
  1994年   67篇
  1993年   73篇
  1992年   52篇
  1991年   73篇
  1990年   67篇
  1989年   62篇
  1988年   68篇
  1987年   44篇
  1986年   45篇
  1985年   41篇
  1984年   31篇
  1983年   34篇
  1982年   25篇
  1981年   28篇
  1980年   21篇
  1979年   21篇
  1978年   25篇
  1977年   15篇
  1976年   18篇
  1973年   19篇
  1972年   15篇
  1969年   19篇
  1967年   15篇
  1966年   16篇
排序方式: 共有3059条查询结果,搜索用时 46 毫秒
91.
AIM:To investigate if the presence of relevant genetic polymorphisms has effect on the effectual clearance of bacteria by monocytes and granulocytes in patients with Crohn’s disease(CD).METHODS:In this study,we assessed the differential responses in phagocytosis by measuring the phagocytic activity and the percentage of active phagocytic monocytes and granulocytes in inflammatory bowel disease patients as well as healthy controls.As both autophagy related like 1(ATG16L1)and immunityrelated guanosine triphosphatase gene are autophagy genes associated with CD and more recently nucleo-tide-binding ligomerization domain-containing protein2(NOD2)has been identified as a potent inducer of autophagy we genotyped the patients for these variants and correlated this to the phagocytic reaction.The genotyping was done with restriction fragment length polymorphisms analysis and the phagocytosis was determined with the pHrodo?Escherichia coli Bioparticles Phagocytosis kit for flowcytometry.RESULTS:In this study,we demonstrate that analysis of the monocyte and granulocyte populations of patients with CD and ulcerative colitis showed a comparable phagocytic activity(ratio of mean fluorescence intensity)between the patient groups and the healthy controls.CD patients show a significantly higher phagocytic capacity(ratio mean percentage of phagocytic cells)compared to healthy controls(51.91%±2.85%vs 37.67%±7.06%,P=0.05).The extend of disease was not of influence.However,variants of ATG16L1(WT:2.03±0.19 vs homozygoot variant:4.38±0.37,P<0.009)as well as NOD2(C-ins)(heterozygous variant:42.08±2.94 vs homozygous variant:75.58±4.34(P=0.05)are associated with the phagocytic activity in patients with CD.CONCLUSION:Monocytes of CD patients show enhanced phagocytosis associated with the presence of ATG16L1 and NOD2 variants.This could be part of the pathophysiological mechanism resulting in the disease.  相似文献   
92.
To evaluate the role of intravenous immunoglobulin (IVIg) in platelet apoptosis in paediatric immune thrombocytopenia, we investigated the platelets of 20 paediatric patients with acute immune thrombocytopenia (ITP), before and after IVIg treatment. Healthy children with platelet counts in the normal range and children with thrombocytopenia due to chemotherapy were enrolled as controls. All ITP patients presented with platelet counts <20 × 109/l and bleeding symptoms. Markers of apoptosis, including activated caspase‐3, ‐8 and ‐9, phosphatidylserine (PS) exposure, mitochondrial inner membrane potential (ΔΨm), as well as platelet‐derived microparticle formation, were analysed by flow cytometry. After IVIg treatment, platelet counts increased to >20 × 109/l in all patients. ITP patients had significantly increased proportions of platelets with activated caspase‐3, ‐8 and ‐9, with PS exposure, and with decreased ΔΨm, and demonstrated increased microparticle formation. Except for ΔΨm, these markers for apoptosis were reduced by IVIg treatment. Platelets of children with thrombocytopenia after chemotherapy also demonstrated increased microparticle formation and decreased ΔΨm, but no activation of caspases 3, 8 and 9 or PS exposure. In conclusion, in acute paediatric ITP, enhanced platelet apoptosis is seen at diagnosis that normalizes after IVIg treatment.  相似文献   
93.
94.
95.
96.
The lack of availability of novel antibiotic agents and the rise of resistance to existing therapies has led clinicians to utilise combination therapy to adequately treat bacterial infections. Here we examined how chelators may impact the in vitro activity of tigecycline (TIG) against Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae. Minimum inhibitory concentrations (MICs) were determined by broth dilution with and without various combinations of chelators (EDTA and other tetracyclines) and metal ions (i.e. calcium, magnesium). Trimethoprim (TMP) was used as a non-chelating control. Addition of metal ions led to increases in MICs, whilst addition of EDTA led to decreases in MICs. The chelating effects of EDTA were reversed by addition of magnesium and most profoundly calcium. Similar effects of EDTA and calcium were observed for tetracycline (TET) and TMP. When other tetracyclines (TET, oxytetracycline (OXY) and chlortetracycline (CHL)) were used as chelators at concentrations below their MICs, TIG MICs decreased for P. aeruginosa but not for E. coli. Some decreases in TIG MICs were observed for K. pneumoniae when TET and CHL were added. A dose-dependent decrease in TIG MIC was observed for TET and was reversed by the addition of calcium. The presence of effects of EDTA and calcium on TMP MICs indicates that mechanisms outside of TIG chelation likely play a role in enhanced activity. Full characterisation of an unexpected interaction such as TIG–TET with different microorganisms could provide valuable insights into the underlying mechanisms and design of physiologically viable chelators as candidates for future combinations regimens.  相似文献   
97.
Long‐term care services are provided to help people manage the consequences of impairment, but their impact goes beyond the meeting of basic needs. Accordingly, the main aim was to explore the marginal effectiveness of care when measured in terms of people's overall care‐related quality of life (CRQoL) and assess changes in marginal effect for increasing intensity. The associated aim was to refine and apply an observational method to estimate marginal effectiveness. A “production function” approach was used with survey data, including Adult Social Care Outcomes Toolkit‐measured CRQoL, whereby we statistically modelled the expected relationship between service utilisation rates and CRQoL. This method seeks to limit endogeneity issues by controlling on observables and using instrumental variable. Using a survey of publicly funded long‐term care service users in England, we found that community‐based long‐term care significantly improved people's CRQoL but with diminishing marginal effects and effects differentiated by baseline impairment levels. There are implications for how the care system should respond to changes in global public budgets. For example, where there is unmet need, a system aimed to maximise (unadjusted) CRQoL would put more emphasis on access (more recipients) than intensity of support compared to a system operating on a needs basis.  相似文献   
98.
99.
Generativity     
Daniel J. Pesut  PhD  RN  CS  FAAN 《Nursing outlook》2002,50(2):49
  相似文献   
100.
Provision of childhood primary care services and differences between types of providers (family practice physicians, pediatricians, nurse practitioners, and physicians' assistants) were explored in this study. A mail survey was conducted in Wyoming using a questionnaire based on the recommendations from the U. S. Preventive Service Task Force. Sixty-one percent of the providers returned questionnaires. While some areas of assessment, screening, and treatment/counseling services were provided at high levels, many were not. Gaps exist particularly in the areas of behavioral and lifestyle assessment and treatment/counseling. Only small differences existed between types of providers. However, nurse practitioners and pediatricians were more likely to report that they followed recommendations, while physicians' assistants were least likely to report that they followed recommendations.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号