全文获取类型
收费全文 | 87744篇 |
免费 | 5099篇 |
国内免费 | 411篇 |
专业分类
耳鼻咽喉 | 957篇 |
儿科学 | 2383篇 |
妇产科学 | 2151篇 |
基础医学 | 10522篇 |
口腔科学 | 1925篇 |
临床医学 | 8982篇 |
内科学 | 19166篇 |
皮肤病学 | 1348篇 |
神经病学 | 7098篇 |
特种医学 | 2692篇 |
外国民族医学 | 2篇 |
外科学 | 13019篇 |
综合类 | 1349篇 |
现状与发展 | 1篇 |
一般理论 | 134篇 |
预防医学 | 7297篇 |
眼科学 | 2335篇 |
药学 | 6145篇 |
4篇 | |
中国医学 | 181篇 |
肿瘤学 | 5563篇 |
出版年
2024年 | 334篇 |
2023年 | 488篇 |
2022年 | 784篇 |
2021年 | 1935篇 |
2020年 | 1235篇 |
2019年 | 1708篇 |
2018年 | 1936篇 |
2017年 | 1367篇 |
2016年 | 1568篇 |
2015年 | 1729篇 |
2014年 | 2553篇 |
2013年 | 3890篇 |
2012年 | 5346篇 |
2011年 | 5724篇 |
2010年 | 3212篇 |
2009年 | 3001篇 |
2008年 | 5287篇 |
2007年 | 5645篇 |
2006年 | 5374篇 |
2005年 | 5459篇 |
2004年 | 5084篇 |
2003年 | 4529篇 |
2002年 | 4380篇 |
2001年 | 1048篇 |
2000年 | 895篇 |
1999年 | 1035篇 |
1998年 | 969篇 |
1997年 | 780篇 |
1996年 | 640篇 |
1995年 | 607篇 |
1994年 | 577篇 |
1993年 | 563篇 |
1992年 | 687篇 |
1991年 | 654篇 |
1990年 | 548篇 |
1989年 | 570篇 |
1988年 | 518篇 |
1987年 | 494篇 |
1986年 | 491篇 |
1985年 | 549篇 |
1984年 | 550篇 |
1983年 | 497篇 |
1982年 | 627篇 |
1981年 | 560篇 |
1980年 | 564篇 |
1979年 | 395篇 |
1978年 | 401篇 |
1977年 | 391篇 |
1976年 | 310篇 |
1975年 | 339篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
Ibrahim Fikry Abdelwahab Stefano Bianchi Carlo Martinoli Michael Klein George Hermann 《Journal l'Association canadienne des radiologistes》2006,57(5):278-286
Tuberculosis involving the soft tissue from adjacent bone or joint is well recognized. However, primary tuberculous pyomyositis, tuberculous bursitis, and tuberculous tenosynovitis are rare entities constituting 1% of skeletal tuberculosis. Tuberculous tenosynovitis involves most commonly the tendon sheaths of the hand and wrist, and tuberculous bursitis occurs most commonly around the hip. The greater trochanteric bursa and the greater trochanter are the most frequent sites of tuberculous bursitis. Cases of primary tuberculous pyomyositis and tenosynovitis of the tendons of the ankle and foot are seldom reported in the radiology literature. All imaging modalities-plain radiography, bone scan, computed tomography, and magnetic resonance imaging (MRI)--provide information that is helpful in determining therapy. MRI in particular, with its multiplanar capabilities and superb contrast of soft tissue, can demonstrate the extent of the soft tissue mass and access the adjacent bones and joints. However, MRI has no diagnostic specificity in regard to tuberculosis, and in nonendemic areas, biopsy is strongly recommended. All patients in this review were permanent residents of North America or Western Europe and were immunocompetent. Examples of atypical presentations of the above entities are demonstrated. 相似文献
12.
13.
14.
Evagelos N Liberopoulos Eleni Papavasiliou George A Miltiadous Marios Cariolou Kostas C Siamopoulos Alexandros D Tselepis Moses S Elisaf 《Peritoneal dialysis international》2004,24(6):580-589
OBJECTIVE: The more atherogenic lipid profile seen in peritoneal dialysis (PD) patients cannot fully explain the increased incidence of atherosclerosis in this population. Oxidative modification of low-density lipoproteins (LDL) is considered to play a central role in the atherogenic process, whereas high-density lipoprotein (HDL) protects LDL from oxidation. On the other hand, it has been suggested that the LDL and HDL of PD patients are more resistant to oxidation than those of control subjects, while PD-HDL equally protects LDL from oxidation compared to control-HDL. Two HDL-associated enzymes have been shown to protect both LDL and HDL from oxidation: paraoxonase (PON1) and HDL-associated platelet-activating factor acetylhydrolase (HDL-PAF-AH). Furthermore, low PON1 activity and high total plasma PAF-AH concentration, which represents mainly the LDL-associated enzyme, have been shown to be independent risk factors for coronary artery events in the general population. However, there are limited data regarding possible alterations of these enzymes in PD patients. The aim of our study was to examine the possible alterations of PON1 and PAF-AH activities in patients undergoing PD. DESIGN: A cross-sectional study. SETTING: A university medical center. PARTICIPANTS: 56 PD patients of Caucasian origin and 86 matched controls were studied. MEASUREMENTS: In all subjects, serum PON1 activity toward paraoxon (paraoxonase) and phenylacetate (arylesterase), as well as total serum and HDL-PAF-AH activities were measured; PON1 genetic polymorphisms known to influence PON1 activity (Q192R and M55L) were determined. RESULTS: The PD patients exhibited significantly increased serum PON1 (paraoxonase) and PON1 (arylesterase) activities compared to controls, regardless of the PON1 polymorphisms or the levels of HDL cholesterol. Additionally, PD patients had significantly elevated activities of total serum PAF-AH and HDL-PAF-AH, independently of the levels of LDL or HDL cholesterol. The ratio of HDL-PAF-AH/ total PAF-AH, which has recently been suggested to be a potential marker of atherogenicity, was decreased in these patients compared to controls. Moreover, no difference in the prevalence of PON1 polymorphisms between PD patients and controls was found. CONCLUSION: The elevated activities of PON1 and HDL-PAF-AH could explain the increased resistance of PD-HDL to oxidation; the higher activity of total PAF-AH and the decreased HDL-PAF-AH/ total PAF-AH ratio could contribute to the increased incidence of atherosclerosis in these patients. 相似文献
15.
16.
Brenda D. Jamerson Pharm.D. George E. Dukes Pharm.D. Kim L.R. Brouwer Pharm.D. Ph.D. Karl H. Dorm Ph.D. John A. Messenheimer M.D. J. Robert Powell Pharm.D. 《Pharmacotherapy》1994,14(1):47-52
Study Objective . To compare the frequency, severity, and time course of venous irritation after administration of a single intravenous dose of phenytoin with an equimolar dose of fosphenytoin, a water-soluble phenytoin prodrug. Design . Randomized, double-blind, two-period, crossover study. Setting . University hospital clinical research unit. Patients . Twelve healthy volunteers within 15% of ideal body weight and with no clinically significant abnormalities on physical examination, medical history, or laboratory assessment. Interventions . Volunteers randomly received a 30-minute infusion of phenytoin sodium 250 mg (250 mg/5 ml) or an equimolar dose of fosphenytoin 375 mg (375 mg/5 ml). Subjects returned for the crossover treatment 14–21 days later. Measurements and Main Results . Subjects assessed venous irritation (pain, burning, itching), and investigators evaluated phlebitis (erythema, swelling, tenderness), induration, exudation, and cording. Phenytoin was associated with a significantly higher degree of pain at the infusion site in all subjects and a significant degree of phlebitis in eight subjects (p<0.05); cording occurred in six subjects. The time course of phenytoin-induced phlebitis was bimodal. Erythema and tenderness were prominent at the end of the infusion and again at 24 hours. Cording was first noted between 24 hours and 1 week after infusion. In contrast, fosphenytoin was associated with mild pain in two subjects, one incident of phlebitis, and no erythema or cording. Conclusions . Fosphenytoin administration resulted in significantly less venous irritation and phlebitis compared with an equimolar dose of phenytoin. The clinical use of this water-soluble phenytoin prodrug should minimize the frequency and severity of infusion-site reactions and should allow convenient, rapid, intravenous administration of drug, undiluted or admixed with intravenous solutions. 相似文献
17.
Gregor McWalter MA MSc Hugh Toner MA DipCouns MSc CPsychol Alison Corser BSc MPhil CPsychol Jenny Eastwood MBChB DipSocMed FRCPsych Mary Marshall MA DSA DASS Tony Turvey BSc MAppSci CPsychol 《Health & social care in the community》1994,2(4):213-219
The concept of need and the practice of needs assessment are both subject to a wide range of interpretations, to the likely detriment of individual assessments and to multidisciplinary working. Clear definition is important for individual assessment, for the development of multidisciplinary tools and in gathering planning information. The concept of need is clarified, firstly by distinguishing between need and the difficulties that engender it, and secondly through a taxonomy of need. These assist clear definitions of both need and needs assessment when linked with a consideration of the current help a person receives and a specification of the type of help required by a person to meet their needs. Such definitions have implications for the role of needs assessment in individual assessment, service evaluation, service management and planning and in the development of multidisciplinary needs assessment tools. 相似文献
18.
George E. Fryer PhD Curtis Stine MD Richard D. Krugman MD Thomas J. Miyoshi 《The Journal of rural health》1994,10(3):193-198
The performance of area health education center (AHEC)-stimulated programs and decentralized education for medicine is not well understood. The Statewide Education Activities for Rural Colorado's Health (SEARCH)/AHEC project at the University of Colorado School of Medicine was examined to determine if the program had an effect on the practice location of its graduates. Practice location and specialty of graduates of the University of Colorado School of Medicine (UCSOM) classes 1980-1985 were compared for students who had participated in decentralized SEARCH/AHEC experiences versus students who had not. The majority of the graduates were practicing out of state in 1990. Non-Colorado doctors were more often practicing in rural (non-metropolitan statistical area [MSA]) counties and in towns of fewer than 2,500, 5,000 and 10,000 residents, respectively. In addition, of the 251 active patient care physicians practicing in Colorado communities of fewer than 10,000 in non-MSA counties in 1986, those who precepted UCSOM students on SEARCH rotations were more likely to have remained in their same practice location in 1992 (77.8% versus 62.1% for those who had not precepted students). This analysis of both student and preceptor practice patterns documents the value of decentralized medical education in addressing the geographic and specialty maldistribution of physicians. These results have important policy implications for funding medical education programs. 相似文献
19.
Changes in regional ventilation and perfusion of the lung after endoscopic laser treatment. 总被引:4,自引:2,他引:2
下载免费PDF全文

To determine whether endoscopic laser treatment improves both ventilation and perfusion in patients with advanced lung cancer, krypton-81m ventilation and technetium-99m labelled macro-aggregate perfusion scanning was performed immediately before and two or four days after treatment in a consecutive series of 28 patients. Twelve patients had not received any other treatment before laser therapy and 16 had undergone previous treatments that included radiotherapy. Ventilation and perfusion were quantified by expressing the number of counts in the affected lung as a percentage of the total counts. Ventilation and perfusion improved after laser treatment in 23 patients (82%). The mean ventilation score in the affected lung rose by 50% (p less than 0.001) and the mean perfusion score rose by 24% (p less than 0.001). Incremental changes in ventilation and perfusion scores were positively correlated (r = 0.80). Mean spirometric values, six minute walking distance, the Karnofsky performance index, and breathlessness and wellbeing scores also improved significantly. Patients with main bronchial obstruction who had had no radiotherapy showed the most striking improvements. It is concluded that the removal of intraluminal tumour from the bronchial tree leads to matched improvements in ventilation and perfusion in most patients and that this is associated with valuable improvement in symptoms. 相似文献
20.
The progressive degeneration of the brain seen in dementia is often accompanied by behavioural disturbances. Aggressive behaviour is one of the most serious of these disturbances and is a common cause for psychiatric referral, admission to hospital and drug treatment. In this article, we discuss the conceptual issues associated with defining aggressive behaviour in cognitively impaired patients. We then review the aetiology, epidemiology, methods of assessment, and management of aggressive behaviour in elderly people with dementia. 相似文献