全文获取类型
收费全文 | 36110篇 |
免费 | 3073篇 |
国内免费 | 155篇 |
专业分类
耳鼻咽喉 | 557篇 |
儿科学 | 868篇 |
妇产科学 | 622篇 |
基础医学 | 4432篇 |
口腔科学 | 956篇 |
临床医学 | 3471篇 |
内科学 | 8074篇 |
皮肤病学 | 445篇 |
神经病学 | 3089篇 |
特种医学 | 1218篇 |
外科学 | 6057篇 |
综合类 | 778篇 |
一般理论 | 28篇 |
预防医学 | 2848篇 |
眼科学 | 863篇 |
药学 | 2465篇 |
中国医学 | 80篇 |
肿瘤学 | 2487篇 |
出版年
2023年 | 132篇 |
2022年 | 213篇 |
2021年 | 599篇 |
2020年 | 349篇 |
2019年 | 613篇 |
2018年 | 700篇 |
2017年 | 592篇 |
2016年 | 566篇 |
2015年 | 632篇 |
2014年 | 1048篇 |
2013年 | 1529篇 |
2012年 | 2274篇 |
2011年 | 2313篇 |
2010年 | 1278篇 |
2009年 | 1221篇 |
2008年 | 2134篇 |
2007年 | 2274篇 |
2006年 | 2437篇 |
2005年 | 2413篇 |
2004年 | 2273篇 |
2003年 | 2273篇 |
2002年 | 2134篇 |
2001年 | 458篇 |
2000年 | 448篇 |
1999年 | 513篇 |
1998年 | 535篇 |
1997年 | 418篇 |
1996年 | 396篇 |
1995年 | 321篇 |
1994年 | 287篇 |
1993年 | 261篇 |
1992年 | 377篇 |
1991年 | 350篇 |
1990年 | 323篇 |
1989年 | 294篇 |
1988年 | 270篇 |
1987年 | 239篇 |
1986年 | 248篇 |
1985年 | 238篇 |
1984年 | 264篇 |
1983年 | 221篇 |
1982年 | 244篇 |
1981年 | 231篇 |
1980年 | 171篇 |
1979年 | 194篇 |
1978年 | 172篇 |
1977年 | 161篇 |
1975年 | 124篇 |
1974年 | 142篇 |
1973年 | 134篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Aims and Objectives The significance of beaten copper appearance (BCA) on skull radiographs in children following surgery for isolated sagittal
craniosynostosis has not been studied. This study was designed to look for any correlation between BCA and symptoms suggestive
of intracranial hypertension in this group of patients.
Materials and Methods Forty-eight consecutive children, who were operated for isolated sagittal synostosis from1987 to 2000 and had postoperative
skull radiographs, were included. Patients were divided into: (a) BCA group (n = 20), consisting of children who had beaten copper appearance on skull radiographs at last follow up, and (b) Non-BCA group
(n = 28), consisting of children who did not have this finding. Records were reviewed to look for symptoms suggestive of intracranial
hypertension, such as headache, head banging, and irritability.
Results Median age at surgery was 4.8 months for BCA group and 4 months for the non-BCA group. Follow up ranged from 4 to 156 months
with a mean of 36.2 months. Total of 28.6% (n = 6) of the children with follow up radiographs done at ≤18 months of age had BCA. The incidence of BCA increased to 83.3%
in children with skull radiographs performed after 48 months of age. In 18 (90%) children, the BCA was ‘diffuse’ with 5 (25%)
children having the maximum possible score of 8. In the BCA group, 45% (n = 9) had symptoms compared to 10.7% (n = 3) in the control group (p = 0.0068).
Conclusions This study suggests a significant number of children with BCA on radiographs develop symptoms suggestive of raised ICP following
surgical treatment in infancy and prolonged follow up may be warranted in this group of patients. 相似文献
62.
The thyroid surgeon must have a full understanding of the anatomy and surgical approaches to the mediastinum. Although most benign substernal goiters may be removed by a transcervical approach, the surgeon needs to know indications for transclavicular and median sternotomy approaches. When there is direct evidence of extension of thyroid cancer into the mediastinum, the possibility of median sternotomy should be considered. This is certainly mandated when disease extends to the inferior mediastinum. Superior mediastinal node dissection is usually easy to approach transcervically. Unilateral extension of the disease may be accessed readily with a transclavicular approach for most cases. Careful dissection of the recurrent laryngeal nerve as well as parathyroids is essential to diminish postoperative morbidity. The morbidity is a reflection of the experience and technical skills of the surgeon as well as the extent of the disease. The best results for resection of substernal thyroid disease are obtained by the experienced thyroid surgeon, not the occasional operator. 相似文献
63.
Daniel B. Costa Christopher A. Fisher Kenneth B. Miller German A. Pihan David P. Steensma Richard J. Gibbons Douglas R. Higgs 《European journal of haematology》2006,76(5):432-435
Abstract: We describe a patient with acquired alpha-thalassemia myelodysplastic syndrome (ATMDS). A previously healthy 66-year-old man presented with hemoglobin of 9.3 g/dL, mean corpuscular volume 59 fL, and a bone marrow aspirate with increased erythroid precursors and hypolobulated megakaryocytes. Hemoglobin H inclusions were seen in most red cells after 1% brilliant cresyl blue supravital stain of the peripheral blood. At the molecular level, we identified of a novel mutation in the most 3' exon of the ATRX gene ( C GA→ T GA substitution in codon 2407) resulting in a premature termination codon (p.R2407X). This case provides further evidence for a link between ATRX mutations and ATMDS, and suggests a possible role for the conserved Q-box element in ATRX function. 相似文献
64.
Best-practice algorithms for the use of a bilayered living cell therapy (Apligraf® ) in the treatment of lower-extremity ulcers 总被引:1,自引:0,他引:1
Joseph Cavorsi MD FACS ; Frank Vicari MD FACS FAAP ; Douglas J. Wirthlin MD FACS ; William Ennis DO MBA FACOS ; Robert Kirsner MD ; Sean M. O''Connell PhD ; John Steinberg DPM ; Vincent Falanga MD 《Wound repair and regeneration》2006,14(2):102-109
Tissue-engineered skin substitutes such as Apligraf have emerged over the past 20 years as among the most carefully studied and efficacious of the advanced wound modalities. These products have been proven as effective enhancements to general wound care, promoting wound closure particularly in instances where conventional wound care fails. Marketed for hard-to-heal wounds since 1998, Apligraf has become part of standard wound care in many wound centers across the United States. Despite this situation, few general wound care guidelines incorporate advanced and active wound-healing technologies, such as tissue-engineered skin products. Because of this deficiency, appropriate patient selection and proper use of these product remain largely unaddressed within the general wound care community. Here, we describe the development of guidelines surrounding optimal use of the bilayered living cell therapy, Apligraf, in the treatment of the two types of lower extremity ulcers for which the product is FDA approved: venous leg ulcer and diabetic foot ulcer. The guidelines detailed in this article focus on the identification and selection of patients who are at risk for failure of standard wound care therapy and thus appropriate for Apligraf treatment. The intended audience for these guidelines is the general wound care practitioner, for whom the developed treatment algorithms and accompanying figure legends should provide practical, user-friendly direction simplifying both patient selection and appropriate use of Apligraf within the context of good wound-healing practice. 相似文献
65.
Estrogen receptor beta polymorphisms are associated with bone mass in women and men: the Framingham Study. 总被引:5,自引:0,他引:5
Amanda M Shearman David Karasik Kristen M Gruenthal Serkalem Demissie L Adrienne Cupples David E Housman Douglas P Kiel 《Journal of bone and mineral research》2004,19(5):773-781
ESR2 is expressed in bone cells, yet few studies have tested its variation for association with BMD, an important determinant of osteoporotic fractures. This was investigated in 723 men and 795 women from the Framingham study. Results show association of variation in this gene with BMD in both women and men. INTRODUCTION: Osteoporotic fracture risk is highly dependent on bone density, a quantitative multifactorial trait with a substantial genetic component. In contrast to the growing body of evidence that estrogen receptor alpha (ESR1) plays a role in bone metabolism, few studies have examined the estrogen receptor beta (ESR2) gene for association with BMD. An ESR2 CA repeat polymorphism, D14S1026, was associated with BMD in two small studies, each with <200 women. MATERIALS AND METHODS: The objective of this investigation was to assess whether D14S1026 or four other intronic polymorphisms were associated with BMD in 723 men and 795 women (mean age, 60 years) from the offspring cohort of the population-based Framingham Study. BMD was measured at the femur (neck, trochanter, and Ward's area) and the lumbar spine (L(2)-L(4)). RESULTS: In both women and men, there was significant association of D14S1026 genotype with measures of femoral but not spinal BMD. In addition, genotypes of two common single nucleotide polymorphisms, rs1256031 and rs1256059, in strong linkage disequilibrium with one another but not with D14S1026, were associated with measures of femoral BMD in men. The rs1256031 genotypes had up to a 4.0% difference in mean femoral BMD. An inferred rs1256031-D14S1026-rs1256059 haplotype C-23CA-T was significantly associated with reduced femoral BMD in women (p = 0.03, 0.003, and 0.01 for neck, trochanter, and Ward's area, respectively). Haplotype-based BMD differences ranged from 3.0% to 4.3%. CONCLUSIONS: We have observed significant association of common ESR2 variants with measures of femoral BMD in both men and women. 相似文献
66.
67.
68.
69.
John S. Witte Giske Ursin Jack Siemiatycki W. Douglas Thompson Annali Paganini-Hill Robert W. Haile 《Breast cancer research and treatment》1997,42(3):243-251
We investigated associations between diet and premenopausal bilateral breast cancer in a familial matched case-control study. We studied 140 cases from population-based registries in Los Angeles County (California) and Connecticut, and from the major hospitals in the southern parts of the Province of Quebec. Unaffected sisters of the cases served as matched controls (222 total). Dietary intake were assessed with a food frequency questionnaire. Total fat, monounsaturated fat, polyunsaturated fat, oleic acid, and linoleic acid intake was inversely associated with premenopausal bilateral breast cancer risk. Consumption of carbohydrates (and sweetened beverages) was associated with an increased risk. We observed no associations for dietary fiber, antioxidants, or major food groupings, but we did observe inverse associations for intake of low fat dairy products and tofu. These findings suggest that monounsaturated and polyunsaturated fats, as well as soy foods, might reduce the risk of premenopausal bilateral breast cancer. 相似文献
70.