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   327篇
  免费   18篇
  国内免费   2篇
儿科学   13篇
妇产科学   1篇
基础医学   36篇
口腔科学   5篇
临床医学   43篇
内科学   119篇
皮肤病学   12篇
神经病学   16篇
特种医学   9篇
外科学   20篇
综合类   6篇
预防医学   23篇
眼科学   30篇
药学   11篇
肿瘤学   3篇
  2023年   1篇
  2022年   1篇
  2021年   5篇
  2020年   4篇
  2019年   5篇
  2018年   7篇
  2017年   8篇
  2016年   8篇
  2015年   4篇
  2014年   7篇
  2013年   10篇
  2012年   13篇
  2011年   26篇
  2010年   9篇
  2009年   13篇
  2008年   23篇
  2007年   13篇
  2006年   11篇
  2005年   17篇
  2004年   15篇
  2003年   13篇
  2002年   15篇
  2001年   10篇
  2000年   11篇
  1999年   5篇
  1998年   5篇
  1997年   9篇
  1996年   13篇
  1995年   10篇
  1994年   5篇
  1993年   4篇
  1992年   8篇
  1991年   6篇
  1990年   5篇
  1989年   4篇
  1988年   3篇
  1987年   3篇
  1986年   2篇
  1985年   4篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1971年   2篇
排序方式: 共有347条查询结果,搜索用时 15 毫秒
341.
OBJECTIVES: To determine the prevalence and type of suboptimal pharmacotherapy that older veterans discharged from the emergency department (ED) or urgent care clinic (UCC) receive and to examine factors associated with suboptimal pharmacotherapy in this population. DESIGN: Retrospective, cohort study. SETTING: An academically affiliated Department of Veterans' Affairs (VA) Medical Center. PARTICIPANTS: Four hundred twenty-one veterans aged 65 and older who were prescribed a new medication at the time of discharge from the ED or UCC. MEASUREMENTS: The primary dependent variable, suboptimal pharmacotherapy, was a composite measure defined as one or more drug-related problems, based on drugs-to-avoid criteria, drug-drug interactions, drug-disease interactions, and failure to satisfy an explicit quality indicator for prescribing or medication monitoring. RESULTS: A total of 757 drugs were prescribed to the 421 patients at the time of discharge from the ED or UCC (mean number+/-standard deviation per patient 1.65+/-1.1). The most frequently prescribed medications were nonsteroidal antiinflammatory drugs (n=59), opioid analgesics (n=47), and fluoroquinolone antibiotics (n=46). Overall, 134 (31.8%) subjects were found to have suboptimal pharmacotherapy with regard to their discharge medications; 49 (11.6%) were prescribed a drug to avoid, 53 (12.6%) received a drug that introduced a new drug-drug interaction, 24 (5.7%) were given a drug that introduced a drug-disease interaction, and 74 (17.6%) did not have a quality indicator satisfied (61% of these evaluated prescribing and 39% evaluated medication monitoring). No consistent associations between patient or visit characteristics and suboptimal pharmacotherapy were identified in multivariable models. CONCLUSION: A substantial number of older adults discharged from the ED or UCC may be at risk for adverse events due to suboptimal prescribing and inadequate medication monitoring. Further study is needed to examine the relationship between suboptimal pharmacotherapy and adverse clinical outcomes.  相似文献   
342.
343.
344.
Metal-on-metal hip-bearing components with different percentages of carbon content (low and high carbon) were tested in 6 different configurations using a hip joint simulator. The aim of this study was to characterize metallurgical and tribological events occurring at the articulating surfaces of these articulations. Also, ion release was evaluated and correlated with wear. After the test, for the high-carbon components, carbides were observed below the matrix surface. In the low-carbon content components, most carbides were "carbide-free", while a minority were worn below the matrix surface with increased test cycles. In the cast alloy components, some carbides were pulled out resulting in micropits. Scanning microscope electron characterization of the tested specimens showed scratches and holes. The surface showed a dominant severe wear mechanism due to third-body particles. A greater amount of ions was released in the lubricant used during the wear test for the smaller diameter compared with the bigger one. This study showed that the metallurgical and tribological events taking place at the articulating surfaces of metal-metal hip implants are numerous and complex. The surface morphology after the test showed the effect of more critical working conditions with smaller diameters.  相似文献   
345.
The extent to which chronic kidney disease (CKD) affects achievement of blood pressure targets is not comprehensively understood. We evaluated the effects of CKD (estimated glomerular filtration rate: <60 mL/min per 1.73 m(2)) on achievement of blood pressure control (nondiabetic: <140/90 mm Hg; diabetic: <130/85 mm Hg) using data from the Guidelines for Drug Therapy of Hypertension Trial. This 15-month study obtained outpatient blood pressures from 3 Veteran's Affairs institutions. Among 9985 subjects with hypertension, we evaluated the association of CKD with achieved control and antihypertensive medication use. We also explored the association between the number of antihypertensives and systolic, diastolic, and pulse pressure. After 15 months, 41% of participants met blood pressure targets. CKD was not associated with control (adjusted odds ratio: 1.04; 95% CI: 0.93 to 1.15). However, CKD was associated with higher odds of use of >or=3 medications among nondiabetic subjects (odds ratio: 1.46; 95% CI: 1.25 to 1.71) and diabetic subjects (odds ratio: 1.40; 95% CI: 1.17 to 1.66). A significant interaction was observed between CKD and the number of antihypertensives as determinants of diastolic and pulse pressures. Among non-CKD participants, a greater number of antihypertensives (0 compared with 4) was associated with wider pulse pressure (Delta5.2 mm Hg; P<0.001), mainly because of higher systolic pressures (Delta3.6 mm Hg; P=0.001). Among participants with CKD, although greater numbers of antihypertensives were associated with even wider pulse pressures (Delta8.3 mm Hg; P<0.001), this was primarily because of lower diastolic pressures (Delta4.8 mm Hg; P<0.01). Among participants with CKD, greater use of antihypertensives was associated with lower diastolic pressures. Given recent evidence suggesting adverse effects of diastolic hypotension, these results suggest potential risks in patients with CKD from aggressive attempts to control systolic blood pressure.  相似文献   
346.
Summary This study was conducted to evaluate the fatigue strength of Ti‐6Al‐4V laser‐welded joints with several diameters and joint openings. Sixty dumbbell rods were machined in Ti‐6Al‐4V alloy with central diameters of 1·5, 2·0 and 3·5 mm. The specimens were sectioned and then welded using two joint openings (0·0 and 0·6 mm). The combination of variables created six groups, which when added to the intact groups made a total of nine groups (n = 10). Laser welding was executed as follows: 360 V per 8 ms (1·5 and 2·0 mm) and 380 V per 9 ms (3·5 mm) with focus and frequency regulated to zero. The joints were finished, polished and submitted to radiographic examination to be analysed visually for the presence of porosity. The specimens were then subjected to a mechanical cyclic test, and the number of cycles until failure was recorded. The fracture surface was examined with a scanning electron microscope (SEM). The Kruskal–Wallis test and Dunn test (α = 0·05) indicated that the number of cycles required for fracture was lower for all specimens with joint openings of 0·6 mm, and for 3·5‐mm‐diameter specimens with joint openings of 0·0 mm. The Spearman correlation coefficient (α = 0·05) indicated that there was a negative correlation between the number of cycles and the presence of porosity. So, laser welding of Ti‐6Al‐4V structures with a thin diameter provides the best conditions for the juxtaposition of parts. Radiographic examination allows for the detection of internal voids in titanium joints.  相似文献   
347.
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