收费全文 | 15945篇 |
免费 | 1515篇 |
国内免费 | 37篇 |
耳鼻咽喉 | 80篇 |
儿科学 | 650篇 |
妇产科学 | 387篇 |
基础医学 | 1677篇 |
口腔科学 | 400篇 |
临床医学 | 1514篇 |
内科学 | 3675篇 |
皮肤病学 | 258篇 |
神经病学 | 1318篇 |
特种医学 | 569篇 |
外国民族医学 | 8篇 |
外科学 | 1891篇 |
综合类 | 239篇 |
预防医学 | 2899篇 |
眼科学 | 296篇 |
药学 | 847篇 |
中国医学 | 3篇 |
肿瘤学 | 786篇 |
2022年 | 117篇 |
2021年 | 209篇 |
2020年 | 194篇 |
2019年 | 227篇 |
2018年 | 313篇 |
2017年 | 279篇 |
2016年 | 266篇 |
2015年 | 292篇 |
2014年 | 371篇 |
2013年 | 554篇 |
2012年 | 636篇 |
2011年 | 659篇 |
2010年 | 425篇 |
2009年 | 416篇 |
2008年 | 569篇 |
2007年 | 634篇 |
2006年 | 646篇 |
2005年 | 600篇 |
2004年 | 623篇 |
2003年 | 549篇 |
2002年 | 562篇 |
2001年 | 539篇 |
2000年 | 445篇 |
1999年 | 533篇 |
1998年 | 279篇 |
1997年 | 304篇 |
1996年 | 323篇 |
1995年 | 220篇 |
1994年 | 172篇 |
1993年 | 215篇 |
1992年 | 351篇 |
1991年 | 322篇 |
1990年 | 326篇 |
1989年 | 332篇 |
1988年 | 271篇 |
1987年 | 283篇 |
1986年 | 279篇 |
1985年 | 283篇 |
1984年 | 203篇 |
1983年 | 171篇 |
1979年 | 223篇 |
1978年 | 157篇 |
1977年 | 150篇 |
1976年 | 130篇 |
1975年 | 152篇 |
1974年 | 171篇 |
1973年 | 143篇 |
1972年 | 156篇 |
1971年 | 121篇 |
1970年 | 114篇 |
Purpose
A hydrogel rectal spacer (HRS) is a medical device that is approved by the U.S. Food and Drug Administration to increase the separation between the prostate and rectum. We conducted a cost-effectiveness analysis of HRS use for reduction in radiation therapy (RT) toxicities in patients with prostate cancer (PC) undergoing external beam RT (EBRT).Methods and Materials
A multistate Markov model was constructed from the U.S. payer perspective to examine the cost-effectiveness of HRS in men with localized PC receiving EBRT (EBRT alone vs EBRT + HRS). The subgroups analyzed included site of HRS placement (hospital outpatient, physician office, ambulatory surgery center) and proportion of patients with good baseline erectile function (EF). Data on EF, gastrointestinal and genitourinary toxicities incidence, and potential risks associated with HRS implantation were obtained from a recently published randomized clinical trial. Health utilities and costs were derived from the literature and the 2018 Physician Fee Schedule and were discounted 3% annually. Quality-adjusted life years (QALYs) and costs were modeled for a 5-year period from receipt of RT. Probabilistic sensitivity analysis and value-based threshold analyses were conducted.Results
The per-patient 5-year incremental cost for spacers administered in a hospital outpatient setting was $3578, and the incremental effectiveness was 0.0371 QALYs. The incremental cost-effectiveness ratio was $96,440/QALY for patients with PC undergoing HRS insertion in a hospital and $39,286/QALY for patients undergoing HRS insertion in an ambulatory facility. For men with good baseline EF, the incremental cost-effectiveness ratio was $35,548/QALY and $9627/QALY in hospital outpatient and ambulatory facility settings, respectively.Conclusions
Based on the current Medicare Physician Fee Schedule, HRS is cost-effective at a willingness to pay threshold of $100,000. These results contain substantial uncertainty, suggesting more evidence is needed to refine future decision-making. 相似文献Main outcome measures In all subjects expiratory volumes were determined and urinary analysis was conducted for hydroxyproline, calcium, phosphorus, and cortisol levels. Osteocalcin, calcium, phosphorus, cortisol, alkaline phosphatase, and γ-glutamyltransferase levels were measured in blood samples. Bone density of the lumbar spine was determined by means of dual-energy x-ray absorptiometry. Nutrition evaluation was based on a 3-day food diary analyzed using progiciel Nutri 91. The nutritional parameters examined were calcium; phosphorus; magnesium; zinc; vitamins A, C, and D; protein; total fiber; oxalates; energy; caffeine; and alcohol in relation to bone density.
Subjects Thirty-one patients with moderate to severe asthma who had been taking more than 1,000 μg beclomethasone per day or the equivalent for more than 2 years and 27 patients with mild asthma who were taking less than 500 μg beclomethasone per day or the equivalent.
Statistical analyses performed Four factor analysis of variance with hierarchized interactions of four levels, Duncan's test, Pearson correlation coefficients.
Results Blood levels of osteocalcin and protein intake were lower in patients with moderate to severe asthma than in those with mild asthma (P<.05). Significant correlations (P<.02) were observed between bone density and calcium intake (r=.40), phosphorus intake (r=.35), protein intake (r=.30), and serum alkaline phosphatase level (r=−.30). Bone density was not significantly different between the two groups of patients with asthma.
Applications A follow-up of patients with asthma who are taking inhaled corticosteroids is needed to assess bone density, osteocalcin levels, and dietary intakes of calcium. Verify if osteocalcin level decreases over time in patients with moderate to severe asthma, monitor possible modifications in bone density, and verify if the correlation between dietary calcium and bone density is maintained. J Am Diet Assoc. 1997;97:1401–1406. 相似文献