全文获取类型
收费全文 | 10585篇 |
免费 | 1029篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 73篇 |
儿科学 | 266篇 |
妇产科学 | 242篇 |
基础医学 | 1411篇 |
口腔科学 | 272篇 |
临床医学 | 1248篇 |
内科学 | 1908篇 |
皮肤病学 | 198篇 |
神经病学 | 1158篇 |
特种医学 | 391篇 |
外科学 | 1567篇 |
综合类 | 286篇 |
一般理论 | 7篇 |
预防医学 | 1073篇 |
眼科学 | 246篇 |
药学 | 869篇 |
中国医学 | 13篇 |
肿瘤学 | 411篇 |
出版年
2022年 | 87篇 |
2021年 | 161篇 |
2020年 | 107篇 |
2019年 | 182篇 |
2018年 | 201篇 |
2017年 | 161篇 |
2016年 | 144篇 |
2015年 | 180篇 |
2014年 | 235篇 |
2013年 | 359篇 |
2012年 | 579篇 |
2011年 | 577篇 |
2010年 | 265篇 |
2009年 | 284篇 |
2008年 | 521篇 |
2007年 | 535篇 |
2006年 | 605篇 |
2005年 | 539篇 |
2004年 | 512篇 |
2003年 | 459篇 |
2002年 | 438篇 |
2001年 | 295篇 |
2000年 | 286篇 |
1999年 | 271篇 |
1998年 | 140篇 |
1997年 | 112篇 |
1996年 | 99篇 |
1995年 | 76篇 |
1994年 | 95篇 |
1993年 | 92篇 |
1992年 | 197篇 |
1991年 | 210篇 |
1990年 | 166篇 |
1989年 | 174篇 |
1988年 | 159篇 |
1987年 | 179篇 |
1986年 | 163篇 |
1985年 | 172篇 |
1984年 | 114篇 |
1983年 | 131篇 |
1982年 | 67篇 |
1981年 | 61篇 |
1980年 | 75篇 |
1979年 | 103篇 |
1978年 | 87篇 |
1977年 | 75篇 |
1976年 | 62篇 |
1975年 | 66篇 |
1974年 | 91篇 |
1973年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
OBJECTIVE: There are currently no studies that have investigated dietary supplement use in the chronic renal insufficiency (CRI) population. The objectives of this study were to determine the prevalence of dietary supplement use in a sample of adults with CRI and to examine whether the prevalence of dietary supplement use was higher in the earlier stages of CRI. DESIGN AND SETTING: Cross-sectional survey conducted at an outpatient nephrology clinic. PATIENTS: Adults (n = 100) with varying degrees of CRI. INTERVENTION: Interview-administered questionnaire. MAIN OUTCOME MEASURES: The questionnaire contained questions related to the use of dietary supplements, attitudes, and beliefs about dietary supplements, as well as medical and demographic data including gender, age, body weight, smoking status, concurrent chronic conditions, prescribed medications, serum creatinine, estimated glomerular filtration rate (GFR), etiology of CRI, income, and education level. RESULTS: The prevalence of dietary supplement use was 45%, with the most frequent use occurring in subjects with a mild to moderate degree of renal insufficiency. There were no significant differences in gender, age, body mass index, smoking status, number of concurrent chronic conditions, number of prescribed medications, income, or education level between supplement users and supplement nonusers. Further analysis of dietary supplement use showed that the number of supplements used ranged from 1 to 5 or more supplements per day, with an overall total of 36 different supplements. Dietary supplement users were significantly more concerned with their health than were supplement nonusers. The most frequent sources of supplement information were physicians and printed material; however, 75% of the dietary supplement users desired further information about their dietary supplements. CONCLUSION: This is the first study to investigate the use of dietary supplements in adults with CRI, and it provides valuable information for health care professionals regarding the dietary supplement use of their patients with CRI. 相似文献
62.
Marathon performance in relation to maximal aerobic power and training indices in female distance runners.
下载免费PDF全文
![点击此处可从《British journal of sports medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The purpose of this study was to examine the relationships of marathon performance time (MPT) to maximal aerobic power (VO2 max), physical characteristics, and training indices recorded for 12 weeks prior to a race in 35 female distance runners. The marathon experience of the subjects ranged from two to fifteen races. Physical and aerobic power characteristics (mean +/- S.D.) were: age, 35.7 +/- 8.5 yr; height, 166.4 +/- 5.7 cm; weight, 55.1 +/- 5.7 kg; body fat, 15.7 +/- 5.0%; VO2 max, 56.5 +/- 6.2 ml . kg-1 . min-1. Marathon time for this race averaged 227.0 +/- 31.6 min. Records from individual training diaries indicated the runners averaged 71.0 +/- 10.0 workout days, 10.0 +/- 10.0 two X day-1 workouts, 81.0 +/- 8.0 total workouts, 12.3 +/- 1.8 mean km . workout-1, 5402.8 +/- 1302.6 total training min, 187.0 +/- 18.0 m . min-1 training pace, 112.2 +/- 32.1 max km . wk-1, 83.1 +/- 23.4 mean km . wk-1, 998.8 +/- 282.6 km . 12 wk-1 and 13.8 +/- 2.4 mean km . day-1. MPT was positively correlated to body mass index (r = 0.52), and body fat (r = 0.52) but negatively related to VO2 max (r = -0.65). MPT was also negatively related to previous marathons completed (r = -0.47), workout days (r = -0.47), two X day-1 workouts (r = -0.52), total workouts (r = -0.56), mean km . workout-1 (r = -0.58), total training min (r = -0.56), m . min-1, training pace (r = -0.66), max km . wk-1 (r = -0.70), mean km . wk-1 (r = -0.74), km . 12 wk-1 (r = -0.74), and mean km . day-1 (r = -0.77). MPT for our population of runners may be predicted (r = 0.82, R2 = 0.68) by the following equation: MPT, (min) = 449.88 - 7.61 (-/x km.day-1 run) - 0.63 (m.min-1, training pace); SEE = +/- 18.4 min. 相似文献
63.
J Lloyd Michener Mary T Champagne Duncan Yaggy Susan D Yaggy Katrina M Krause 《Academic medicine》2005,80(1):57-61
Academic medical centers (AMCs) have traditionally provided primary care for low-income and other underserved populations. However, they have had difficulty developing lasting partnerships with other organizations serving the same populations. This article describes an exception to the rule, in which an academic division was created at Duke University Medical Center to develop effective collaborations with health care and social service providers in Durham, North Carolina, including both public agencies and private organizations. Together, the division and its partners have created and operate programs that improve health outcomes and access to care for those at risk. These programs share a number of characteristics: they are designed to meet the needs of the patient, not the provider; they are based in the community, not in the AMC; they bring services to people's homes, schools, and neighborhoods; they are multidisciplinary, combining health, social, and even mental health services; and, once established, they are revenue-generating and can be made self-supporting when grant funding ends. These programs are also innovative. They are designed to model and test new ways of organizing and delivering care. Preliminary indications suggest that they also strengthen the AMC's relationships with the surrounding community. 相似文献
64.
65.
Urinary cytokines following photodynamic therapy for bladder cancer. A preliminary report 总被引:1,自引:0,他引:1
This preliminary study was undertaken to test for the presence of urinary cytokines whose detection would provide evidence in support of the theory that photodynamic therapy (PDT) produces an immunologic response in patients treated for bladder cancer. Gamma interferon, interleukin 1-beta, interleukin 2, and tumor necrosis factor-alpha were assayed for in the urine of 4 patients treated with photodynamic therapy for bladder cancer, in 7 control patients undergoing transurethral surgical procedures, and in 5 healthy control subjects. Quantifiable concentrations of all cytokines, except gamma interferon, were measured in urine samples from the PDT patients with the highest light energies, while no urinary cytokines were found in the PDT patient who received the lowest light energy nor in any of the control subjects. These findings suggest that a local immunologic response may occur following PDT for bladder cancer. 相似文献
66.
L E Witherell L F Novick K M Stone R W Duncan L A Orciari S J Kappel D A Jillson 《Journal of environmental health》1986,49(3):134-139
Legionellosis (Legionnaires' disease and Pontiac fever) outbreaks have been associated with aerosols ejected from contaminated cooling towers--wet-type heat rejection units (WTHRUs) used to dissipate unwanted heat into the atmosphere. The Vermont Department of Health undertook a program to inventory, inspect, and sample all WTHRUs in Vermont from April 1981 to April 1982. All WTHRUs were sampled for Legionella pneumophila and data were obtained for location, design, construction, and operating characteristics. Of the 184 WTHRUs operating, statistical analyses were performed on those 130 which were sampled for L. pneumophila only once during the study period. Of these, 11 (8.5%) were positive for L. pneumophila. Sources of makeup water and period of operation had significant association with the recovery of L. pneumophila. Five out of 92 towers (5.4%) utilizing surface water sources for cooling were positive for L. pneumophila, in contrast to 6 positive towers of the 38 units (15.8%) which obtained makeup water from ground water sources (p = .054 by chi-square test). Nearly 15% of the 54 units which operated throughout the year were positive, compared to less than 4% of the 76 towers operating seasonally (p = .03 by chi-square test). The mean pH of the cooling water in units where L. pneumophila was recovered (8.3) was significantly higher than the mean pH of 7.9 in units testing negative (p less than .05 by t-test). In addition, the mean log-transformed turbidity of positive towers, 0.03 nephelometric units (ntu), was significantly lower than the mean of log turbidity of negative towers, 0.69 ntu (p less than .02 by t-test). 相似文献
67.
68.
69.
Summary Surgical repair of enterocutaneous fistulae in Crohn’s disease may result in large skin defects of the anterior abdominal
wall. We present a case in which a large defect was managed with reconstruction using a pedicled rectus abdominis mycocutaneous
flap in a single procedure. The case highlights the technical challenge of such a case and the value of a joint surgical approach
between plastic and colorectal services. 相似文献
70.
Robert K. McNamara R. Duncan Kirkby Gregory E. dePape Ronald W. Skelton Michael E. Corcoran 《Hippocampus》1993,3(2):149-152
There is some controversy about the role of long-term potentiation (LTP) in spatial learning. The authors have found that triggering generalized kindled seizures with stimulation of the perforant path disrupts spatial learning in the Morris water maze but that kindling per se does not affect spatial learning. It is suggested that abnormal electrical activity induced by high-frequency stimulation of the perforant path may have been responsible for the disruption of spatial learning previously attributed to LTP saturation. 相似文献