全文获取类型
收费全文 | 36616篇 |
免费 | 3257篇 |
国内免费 | 153篇 |
专业分类
耳鼻咽喉 | 551篇 |
儿科学 | 875篇 |
妇产科学 | 683篇 |
基础医学 | 4625篇 |
口腔科学 | 894篇 |
临床医学 | 3538篇 |
内科学 | 8183篇 |
皮肤病学 | 349篇 |
神经病学 | 3099篇 |
特种医学 | 1211篇 |
外科学 | 6206篇 |
综合类 | 824篇 |
一般理论 | 25篇 |
预防医学 | 2919篇 |
眼科学 | 956篇 |
药学 | 2562篇 |
中国医学 | 79篇 |
肿瘤学 | 2447篇 |
出版年
2021年 | 595篇 |
2020年 | 344篇 |
2019年 | 604篇 |
2018年 | 703篇 |
2017年 | 582篇 |
2016年 | 573篇 |
2015年 | 660篇 |
2014年 | 1064篇 |
2013年 | 1539篇 |
2012年 | 2303篇 |
2011年 | 2352篇 |
2010年 | 1308篇 |
2009年 | 1254篇 |
2008年 | 2155篇 |
2007年 | 2332篇 |
2006年 | 2498篇 |
2005年 | 2442篇 |
2004年 | 2289篇 |
2003年 | 2334篇 |
2002年 | 2173篇 |
2001年 | 511篇 |
2000年 | 510篇 |
1999年 | 553篇 |
1998年 | 550篇 |
1997年 | 423篇 |
1996年 | 389篇 |
1995年 | 337篇 |
1994年 | 308篇 |
1993年 | 274篇 |
1992年 | 370篇 |
1991年 | 333篇 |
1990年 | 314篇 |
1989年 | 318篇 |
1988年 | 279篇 |
1987年 | 245篇 |
1986年 | 254篇 |
1985年 | 256篇 |
1984年 | 256篇 |
1983年 | 225篇 |
1982年 | 236篇 |
1981年 | 236篇 |
1980年 | 176篇 |
1979年 | 177篇 |
1978年 | 182篇 |
1977年 | 159篇 |
1976年 | 127篇 |
1975年 | 120篇 |
1974年 | 150篇 |
1973年 | 143篇 |
1972年 | 130篇 |
排序方式: 共有10000条查询结果,搜索用时 671 毫秒
81.
82.
PURPOSE: To review the effects of the long QT syndrome (LQTS) in the parturient and the current anesthetic management of patients with LQTS. SOURCE: Relevant articles were obtained from a MEDLINE search spanning the years 1980-2006 and a PubMed search spanning the years 1949-2006. Bibliographies of retrieved articles were searched for additional articles. PRINCIPAL FINDINGS: The prevalence of LQTS in the developed world is one per 1,100 to 3,000 of the population. Clinically, LQTS is characterized by syncope, cardiac arrest and occasionally, by a history of seizures. The QT interval can also be prolonged by drugs, electrolyte imbalances, toxins and certain medical conditions. Long QT syndrome patients are at risk of torsades de pointes and ventricular fibrillation. Medical management aims to reduce dysrhythmia frequency. The LQTS is subdivided into different groups (LQT1-6) depending on the cardiac ion channel abnormality. Torsades can be precipitated by adrenergic stimuli such as stress or pain (LQT1 and 2), sudden noises (LQT2) or whilst sleeping (LQT3). Patients with LQTS require careful anesthetic management as they are at high risk of torsades perioperatively despite minimal data on the effects of anesthetic agents on the QT interval. While information on effects of LQTS in pregnancy is limited, the incidence of dysrhythmia increases postpartum. Isolated case reports of patients with LQTS women highlight several peripartum dysrhythmias. CONCLUSION: An understanding of LQTS and the associated risk factors contributing to dysrhythmias is important for anesthesthesiologists caring for parturients with LQTS. 相似文献
83.
Caroline Bolton-Smith Marion E T McMurdo Colin R Paterson Patricia A Mole Julia M Harvey Steven T Fenton Celia J Prynne Gita D Mishra Martin J Shearer 《Journal of bone and mineral research》2007,22(4):509-519
Dietary supplementation with vitamin K(1), with vitamin D(3) and calcium or their combination, was examined in healthy older women during a 2-year, double-blind, placebo-controlled trial. Combined vitamin K with vitamin D plus calcium was associated with a modest but significant increase in BMC at the ultradistal radius but not at other sites in the hip or radius. INTRODUCTION: The putative beneficial role of high dietary vitamin K(1) (phylloquinone) on BMD and the possibility of interactive benefits with vitamin D were studied in a 2-year double-blind, placebo-controlled trial in healthy Scottish women > or =60 years of age. MATERIALS AND METHODS: Healthy, nonosteoporotic women (n = 244) were randomized to receive either (1) placebo, (2) 200 microg/day vitamin K(1), (3) 10 microg (400 IU) vitamin D(3) plus 1000 mg calcium/day, or (4) combined vitamins K(1) and D(3) plus calcium. Baseline and 6-month measurements included DXA bone mineral scans of the hip and wrist, markers of bone turnover, and vitamin status. Supplementation effects were tested using multivariate general linear modeling, with full adjustment for baseline and potential confounding variables. RESULTS: Significant bone mineral loss was seen only at the mid-distal radius but with no significant difference between groups. However, women who took combined vitamin K and vitamin D plus calcium showed a significant and sustained increase in both BMD and BMC at the site of the ultradistal radius. Serum status indicators responded significantly to respective supplementation with vitamins K and D. Over 2 years, serum vitamin K(1) increased by 157% (p < 0.001), the percentage of undercarboxylated osteocalcin (%GluOC) decreased by 51% (p < 0.001), serum 25-hydroxyvitamin D [25(OH)D] increased by 17% (p < 0.001), and PTH decreased by 11% (p = 0.049). CONCLUSIONS: These results provide evidence of a modest synergy in healthy older women from nutritionally relevant intakes of vitamin K(1) together with supplements of calcium plus moderate vitamin D(3) to enhance BMC at the ultradistal radius, a site consisting of principally trabecular bone. The substantial increase in gamma-carboxylation of osteocalcin by vitamin K may have long-term benefits and is potentially achievable by increased dietary intakes of vitamin K rather than by supplementation. 相似文献
84.
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
85.
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
86.
David S. Yee Joel Gelman Douglas W. Skarecky Thomas E. Ahlering 《Journal of robotic surgery》2007,1(2):151-154
Fossa navicularis strictures following radical prostatectomy are reported infrequently. We recently experienced a series of
fossa strictures following robotic-assisted laparoscopic prostatectomy (RLP). We describe herein our experience to prevent
fossa strictures and to determine its etiologic factors. From June 2002 to May 2006, 424 patients underwent robotic-assisted
laparoscopic prostatectomy with the da Vinci surgical system. Fossa strictures were diagnosed based on the acute onset of
obstructive voiding symptoms and bougie calibration. During our series, we switched from the intra-operative use of an 18
French (F) catheter to that of a 22 F one to avoid inadvertent stapling of the urethra when dividing the dorsal venous complex.
After we observed a high incidence of fossa strictures, we reverted back to 18 F catheters during surgery. All patients had
an 18 F catheter indwelling for 1 week after surgery. Parameters were evaluated using Fisher’s exact test and Student’s t-test for means. The 18 F catheter group of patients (n = 293) developed one fossa stricture, whereas the 22 F catheter group (n = 131) developed nine fossa strictures (P < 0.01). The fossa stricture rate in the 18 F group was 0.3% versus 6.9% in the 22 F group. The two groups had no differences
in age, body mass index, cardiovascular disease, American Urological Association symptom score, urinary bother score, preoperative
prostate-specific antigen, operative time, estimated blood loss, cautery use, prostate size, or catheterization time. Based
on these results, a larger urethral catheter size – 20 F versus 18 F – during the intra-operative dissection would appear
to increase the risk for fossa stricture by more than 20-fold.
Statement of disclosure Dr. Thomas Ahlering is a meeting participant and lecturer for Intuitive Surgical Corp. The other authors have no direct or
indirect commercial financial incentives associated with publishing the article. No research or project support funding was
received. 相似文献
87.
88.
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
89.
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
90.