全文获取类型
收费全文 | 93225篇 |
免费 | 9498篇 |
国内免费 | 203篇 |
专业分类
耳鼻咽喉 | 1263篇 |
儿科学 | 2744篇 |
妇产科学 | 2063篇 |
基础医学 | 13629篇 |
口腔科学 | 2216篇 |
临床医学 | 11561篇 |
内科学 | 16767篇 |
皮肤病学 | 1447篇 |
神经病学 | 7774篇 |
特种医学 | 3039篇 |
外国民族医学 | 11篇 |
外科学 | 12890篇 |
综合类 | 1898篇 |
一般理论 | 75篇 |
预防医学 | 10491篇 |
眼科学 | 2023篇 |
药学 | 7288篇 |
1篇 | |
中国医学 | 93篇 |
肿瘤学 | 5653篇 |
出版年
2021年 | 1278篇 |
2020年 | 863篇 |
2019年 | 1299篇 |
2018年 | 1594篇 |
2017年 | 1161篇 |
2016年 | 1282篇 |
2015年 | 1459篇 |
2014年 | 1920篇 |
2013年 | 2997篇 |
2012年 | 4095篇 |
2011年 | 4365篇 |
2010年 | 2375篇 |
2009年 | 2259篇 |
2008年 | 3805篇 |
2007年 | 4123篇 |
2006年 | 4028篇 |
2005年 | 3990篇 |
2004年 | 3788篇 |
2003年 | 3590篇 |
2002年 | 3455篇 |
2001年 | 3020篇 |
2000年 | 3114篇 |
1999年 | 2755篇 |
1998年 | 1222篇 |
1997年 | 990篇 |
1996年 | 895篇 |
1995年 | 874篇 |
1994年 | 887篇 |
1993年 | 821篇 |
1992年 | 2281篇 |
1991年 | 2227篇 |
1990年 | 2111篇 |
1989年 | 2023篇 |
1988年 | 1948篇 |
1987年 | 1930篇 |
1986年 | 1870篇 |
1985年 | 1834篇 |
1984年 | 1512篇 |
1983年 | 1365篇 |
1982年 | 907篇 |
1981年 | 785篇 |
1979年 | 1302篇 |
1978年 | 942篇 |
1977年 | 831篇 |
1976年 | 783篇 |
1975年 | 781篇 |
1974年 | 936篇 |
1973年 | 825篇 |
1972年 | 791篇 |
1971年 | 707篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
We observed three children, aged 1 year 8 months to 9 years 7 months, in whom herpes simplex blepharoconjunctivitis resolved promptly without treatment. A fourth child, 8 years old, developed probable toxic manifestations from topical vidarabine. These manifestations, as well as the blepharoconjunctivitis, resolved when the medication was discontinued. Herpes simplex ocular infection without corneal involvement in children is usually benign and self-limited. 相似文献
72.
P M Battey J T Fulenwider R B Smith L G Martin M T Stewart G D Perdue 《Southern medical journal》1987,80(4):479-482
Peripheral arterial thromboembolism and thrombosis of arterial grafts continue to threaten viability of extremities. Percutaneous intra-arterial thrombolysis (IAT) and angiodilatation have afforded limb salvage in some of these patients. Proper patient selection appears to be the hallmark of success with IAT. During a recent three-year period, we used IAT in 32 extremities in 28 patients who had acute arterial insufficiency. Before IAT, 16 extremities were painful at rest, and 16 had incapacitating claudication. The overall success rate was 38%, but some degree of thrombolysis occurred in 88%. Limb salvage was achieved in 27 of 32 extremities (84%). Only five of 17 limbs (29%) with arterial graft thrombosis required no operation or an operation of lesser magnitude than predicted before IAT. Of six extremities with native arterial embolism, four (67%) were completely cleared with IAT. Major complications occurred in eight cases (25%), with two IAT-related deaths (6%). This study suggests that IAT is best reserved for individuals with acute limb ischemia caused by arterial embolus, those whose degree of ischemia would tolerate a 24-hour trial of IAT, and those whose femoral or tibial runoff is not likely to require remedial operation. 相似文献
73.
Dipankar Nandi Helen Smith Sarah Owen Carole Joint John Stein Tipu Aziz 《Journal of clinical neuroscience》2002,9(5):557-561
Central post stroke pain is often difficult to manage satisfactorily with conventional treatment modalities for pain. In the last decade functional neurosurgery has offered hope with motor cortex stimulation achieving significant alleviation of pain in some patients. Unfortunately this has led to the neglect of chronic stimulation of deep grey matter as another modality of treating this condition. In this article we present our experience with motor cortex stimulation and that with deep grey matter stimulation in patients with post stroke pain. We argue that both modalities have a significant role and that what is required are better methods of identifying particular patients who are more likely to respond to one or the other. 相似文献
74.
Human papillomavirus genotype distribution in low-grade cervical lesions: comparison by geographic region and with cervical cancer. 总被引:13,自引:0,他引:13
Gary M Clifford Rashida K Rana Silvia Franceschi Jennifer S Smith Gerald Gough Jeanne M Pimenta 《Cancer epidemiology, biomarkers & prevention》2005,14(5):1157-1164
Low-grade squamous intraepithelial lesions (LSIL) associated with certain human papillomavirus (HPV) genotypes may preferentially progress to cervical cancer. HPV genotyping may thus have the potential to improve the effectiveness of screening programs and to reduce overtreatment. LSIL cases (n = 8,308) from 55 published studies were included in a meta-analysis. HPV genotype distribution was assessed by geographic region and in comparison with published data on cervical squamous cell carcinoma (SCC). HPV detection in LSIL was 80% in North America but less than 70% in other regions, most likely reflecting regional differences in LSIL diagnosis. Among 5,910 HPV-positive LSILs, HPV16 was the most common genotype (26.3%) followed by HPV31 (11.5%), HPV51 (10.6%), and HPV53 (10.2%). HPV-positive LSILs from Africa were 2-fold less likely to be infected with HPV16 than those in Europe, and HPV-positive LSILs from North America were more likely to be infected with HPV18 than those from Europe or South/Central America. Interpretation for rarer genotypes was hampered by variation in HPV testing methodology. SCC/LSIL prevalence ratios indicated that HPV16 was 2-fold and HPV18 was 1.5-fold more common in SCC than in HPV-positive LSIL, thus appearing more likely to progress than other high-risk genotypes (SCC/LSIL prevalence ratios between 0.05 and 0.85). HPV53 and HPV66 showed SCC/LSIL ratios of 0.02 and 0.01, respectively. HPV genotype distribution in LSIL differs from that in cervical cancer, highlighting the importance of HPV genotype in the risk of progression from LSIL to malignancy. Some regional differences in the relative importance of HPV genotypes in LSIL were noted. 相似文献
75.
Glenn Roberts John Somers Jocelyn Dawe Rowena Passy Carly Mays Graham Carr David Shiers Jo Smith 《Early intervention in psychiatry》2007,1(2):168-176
Aims: On the Edge is a mental health education programme designed to support early intervention by increasing knowledge and understanding of early psychosis, reducing the stigma associated with mental health issues and improving awareness of avenues of help. The target audience was young people aged 14–22 years in schools and colleges. Methods: An interactive drama programme was developed through collaborative working across psychiatry, applied drama and those with direct experience of psychosis. A national tour engaged 2500 students in 71 performances that took place in 51 schools and colleges. The programme was evaluated against its aims with data collected both during and after the tour. Results: Quantitative and qualitative evaluation found significant gains with respect to all three aims. Thirty‐one schools developed supportive links with local mental health services. Conclusions: This programme shows the value and effectiveness of delivering health education on early psychosis through the medium of applied drama, and offers a model for a programme that can be incorporated into early intervention services. Lessons learned through delivering this programme are a valuable contribution towards future developments of mental health education programmes for schools. 相似文献
76.
Do frail, disabled, poor, and very old Medicare beneficiaries have higher hospital charges? 总被引:2,自引:0,他引:2
To determine whether basing payments on diagnosis related groups (DRGs) results in mispayment for certain classes of patients, we examined the relation between total Medicare charges per hospitalization and eight beneficiary characteristics (including admission from a nursing home, extreme age, Medicaid enrollment, and disability). We controlled for the hospital in which care was given and the DRG to which the discharge was assigned. The largest effects were that average charges were 6.7% higher for beneficiaries who were disabled before the age of 65 years, and 6.2% higher for patients admitted from a nursing home; charges were 1.5% lower for Medicare beneficiaries who were also enrolled in Medicaid, 3.8% higher for those older than 80 years, and 1.3% lower for those older than 85 years compared with those aged from 80 to 84 years. Because these differences are very small compared with the average variation within DRGs, we conclude that using these beneficiary characteristics in the DRG classification system would only slightly improve DRGs. Medicare's DRG-based payments seem to be substantially equitable with regard to these beneficiary characteristics. 相似文献
77.
K J Meador J L Thompson D W Loring A M Murro D W King B B Gallagher G P Lee J R Smith H F Flanigin 《Neurology》1991,41(6):869-872
Although there has been extensive examination of the behavioral and physiologic correlates of hippocampal theta activity in animals, the human literature consists of a single case study. We investigated the differential effects of four behavioral states on human hippocampal theta activity in 16 epilepsy surgery patients. Behavioral conditions included resting eyes closed (RC), resting eyes open (RO), eyes open with auditory word activation (AW), and eyes open with visuospatial activation (VS). Hippocampal theta activity decreased during both RO and VS compared to both RC and AW. There were reciprocal changes in delta activity. Comparisons of RO to VS and of RC to AW were nonsignificant. The results demonstrate state-specific changes in human hippocampal theta and are consistent with the animal literature that relates hippocampal theta to sensorimotor integration and forebrain volitional mechanisms. 相似文献
78.
79.
C. Olgart Höglund J. Axén C. Kemi S. Jernelöv J. Grunewald C. Müller-Suur Y. Smith R. Grönneberg A. Eklund P. Stierna M. Lekander 《Clinical and experimental allergy》2006,36(8):982-992
BACKGROUND: Stress can aggravate the allergic inflammation, but determinants of disturbed immune regulation are largely unknown. OBJECTIVE: To determine systemic immunological, local inflammatory and functional airway responses to stress in healthy and atopic individuals. METHODS: Forty-one undergraduate students, 22 with allergy of whom 16 had asthma, and 19 healthy controls, were studied in a low-stress period and in association with a large exam. Subjects completed questionnaires on stress and health behaviours, underwent lung function tests, bronchial methacholine challenge, measurements of exhaled nitric oxide and urine cortisol. Blood cells were phenotyped, and cytokines from mononuclear blood cells were analysed. RESULTS: Perceived stress and anxiety increased in both groups during the exam period while cortisol increased only in the atopy group. Cytokine production decreased broadly in response to stress in both groups, which was paralleled by an increase in the proportion of regulatory T cells (CD4(+)CD45RO(+)CD25(bright)). Interestingly, atopic individuals, but not controls, reacted with a decreased T-helper type 1/T-helper type 2 (Th1/Th2) ratio and a decrease in natural killer (NK) cell numbers in response to stress. In control subjects only, exhaled nitric oxide decreased and forced expiratory volume in one second increased during stress. CONCLUSION: Atopic and non-atopic subjects shared some immune changes in response to stress, such as a dramatic decline in cytokines and an increase in the number of regulatory T cells in peripheral blood. However, other stress-induced immune changes were unique to atopic individuals, such as a skewed Th1/Th2 ratio and reduced NK cell numbers, indicating that some pathogenic mechanisms in atopics may be more strongly affected by stress than others. 相似文献
80.