全文获取类型
收费全文 | 1679篇 |
免费 | 87篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 36篇 |
妇产科学 | 20篇 |
基础医学 | 411篇 |
口腔科学 | 12篇 |
临床医学 | 163篇 |
内科学 | 295篇 |
皮肤病学 | 5篇 |
神经病学 | 60篇 |
特种医学 | 70篇 |
外科学 | 487篇 |
综合类 | 19篇 |
预防医学 | 28篇 |
眼科学 | 65篇 |
药学 | 52篇 |
中国医学 | 1篇 |
肿瘤学 | 40篇 |
出版年
2022年 | 14篇 |
2021年 | 16篇 |
2020年 | 17篇 |
2019年 | 34篇 |
2018年 | 28篇 |
2017年 | 16篇 |
2016年 | 17篇 |
2015年 | 34篇 |
2014年 | 47篇 |
2013年 | 54篇 |
2012年 | 62篇 |
2011年 | 79篇 |
2010年 | 58篇 |
2009年 | 51篇 |
2008年 | 63篇 |
2007年 | 69篇 |
2006年 | 50篇 |
2005年 | 53篇 |
2004年 | 75篇 |
2003年 | 48篇 |
2002年 | 55篇 |
2001年 | 46篇 |
2000年 | 47篇 |
1999年 | 60篇 |
1998年 | 24篇 |
1997年 | 20篇 |
1996年 | 13篇 |
1993年 | 12篇 |
1992年 | 16篇 |
1990年 | 13篇 |
1988年 | 16篇 |
1987年 | 14篇 |
1986年 | 15篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1974年 | 12篇 |
1973年 | 13篇 |
1971年 | 17篇 |
1966年 | 14篇 |
1965年 | 12篇 |
1935年 | 16篇 |
1934年 | 34篇 |
1931年 | 16篇 |
1930年 | 15篇 |
1929年 | 12篇 |
1926年 | 12篇 |
1925年 | 25篇 |
1924年 | 27篇 |
1923年 | 40篇 |
1922年 | 28篇 |
排序方式: 共有1768条查询结果,搜索用时 15 毫秒
21.
V Kelemouridis M R Eckstein A G Dembner A C Waltman C A Athanasoulis 《International angiology》1985,4(3):369-371
Does a normal leg phlebogram exclude deep venous thrombosis (DVT)? Is it safe not to anticoagulate patients with suspected DVT and a normal phlebogram? To answer these questions a retrospective study was undertaken of 71 outpatients with clinically suspected DVT and a normal phlebogram. Patients were followed for 5 months on the average; data were obtained from conversations with referring physicians and interviews with patients. Nine patients were excluded from the study because of incomplete follow-up data; four others were excluded because they were treated with coumadin "on clinical grounds". Five patients continued having symptoms subsequently attributed to arthritis, cellulitis and/or venous stasis. Fifty-three patients had no venous thromboembolic problems during the follow-up period and their symptoms subsided without therapy. We conclude that a properly performed normal leg phlebogram excludes a diagnosis of clinically significant DVT. No patient in this study developed problems because anticoagulant therapy was withheld based on a negative phlebogram. 相似文献
22.
R Vijayanagar D Bognolo P Eckstein D Jeffery E Harrison J Kerpchar E Willard R Musunuru 《The Journal of cardiovascular surgery》1987,28(5):576-580
Questions regarding the relative safety and efficacy of internal mammary artery (IMA) grafts versus saphenous vein grafts (SVG) in patients with left main coronary artery disease (LMCAD) have not been specifically addressed in the literature. To elucidate this point, we analyzed 196 patients with LMCAD who underwent myocardial revascularization between January 1975 and December 1981, 98 by IMA and SVG and 98 by SVG, IMA was used most often to bypass the left anterior descending (LAD). Chi Square and "t" tests were performed on all demographic, cardiac and operative data comparing IMA to SVG. All results were non-significant, indicating that the two groups were comparable. Anginal pattern was progressive or unstable in 93%. IMA was used in 4 patients who were on intra-aortic balloon pump. The mean number bypass grafts per patient was 3.1. Postoperative complications were comparable for both groups, including early and late myocardial infarction. Overall operative mortality was 2.6%. Results of a survival analysis indicated no significant difference in the mortality rates of patients operated on by SVG versus IMA-SVG. Cumulative mortality rates at a mean followup of 20.5 months were 12.2% for SVG and 7.1% for IMA patients. Significant mortality risk factors were ejection fraction less than 55% (p less than 0.05); and perioperative myocardial infarction (p less than 0.001). Twenty-five patients with recurrent chest pain underwent repeat cardiac catheterization. This revealed 10 of 10 patent IMA grafts, 6 of 8 single patent SVG to LAD and 6 of 9 patent sequential vein grafts to the diagonal and LAD arteries.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
23.
Simone Eckstein Rosina Ehmann Abderraouf Gritli Houcine Ben Yahia Manuel Diehl Roman Wlfel Mohamed Ben Rhaiem Kilian Stoecker Susann Handrick Mohamed Ben Moussa 《Emerging infectious diseases》2021,27(7):1964
Free-roaming camels, especially those crossing national borders, pose a high risk for spreading Middle East respiratory syndrome coronavirus (MERS-CoV). To prevent outbreaks, active surveillance is necessary. We found that a high percentage of dromedaries in Tunisia are MERS-CoV seropositive (80.4%) or actively infected (19.8%), indicating extensive MERS-CoV circulation in Northern Africa. 相似文献
24.
25.
Precision and intersite correlation of bone densitometry at the radius, tibia and femur with peripheral quantitative CT 总被引:2,自引:0,他引:2
Objective. To compare the in situ precision of peripheral quantitative CT (pQCT) at the radius, tibia and femur, and to analyze the
intersite correlation, in order to determine whether measurements at the lower extremity reproduce results at the radius or
are of additional informative value.
Design and material. pQCT measurements were performed in 86 elderly cadavers (mean age 80.5 years) at trabecular and cortical locations in the
radius, tibia and femur, determining densitometric (bone mineral content and density) as well as geometric parameters (cross-sectional
area, cortical thickness, polar moment of inertia and others). In 14 cadavers, repeated measurements were obtained at all
sites on four different days.
Results and conclusions. At cortical sites, the precision for the densitometric and geometric variables ranged from 0.4% to 4.3%, and was similar
for the radius, tibia and femur. At trabecular locations, the reproducibility of the density measurements ranged from 1.8%
to 2.5% at the radius, and from 3.2% to 5.9% at the femur and tibia. The intersite correlation of the total bone mineral content
ranged from 0.87 and 0.97 at cortical sites, and from 0.63 to 0.85 at trabecular locations. The trabecular density showed
a higher similarity between the tibia and femur (r=0.68–0.78) than between the radius and the lower extremity (r=0.41–0.45). The results demonstrate a substantial heterogeneity of trabecular bone in elderly individuals and advocate measurements
directly at the site of clinical or scientific interest.
Received: 5 July 1999 Revision requested: 12 August 1999 Revision received: 31 August 1999 Accepted: 13 September 1999 相似文献
26.
Three-dimensional analysis of the width of the subacromial space in healthy subjects and patients with impingement syndrome 总被引:4,自引:0,他引:4
Graichen H Bonel H Stammberger T Haubner M Rohrer H Englmeier KH Reiser M Eckstein F 《AJR. American journal of roentgenology》1999,172(4):1081-1086
OBJECTIVE: The aim of this study was to per form a three-dimensional analysis of the width of the subacromial space during passive and active arm abduction in healthy volunteers and patients with impingement syndrome. SUBJECTS AND METHODS: The shoulders of 10 healthy subjects and 10 patients with impingement syndrome were imaged with an open MR system during abduction, with and without activation of the shoulder muscles. An apparatus was designed for applying an adduction force of 10 N to the distal humerus during image acquisition, and the minimal acromiohumeral distance was measured after three-dimensional reconstruction. RESULTS: In the 10 healthy volunteers, muscle activity led to a significant decrease (-32%; p < .05) of the acromiohumeral distance at 60 degrees of abduction, whereas at 120 degrees of abduction the distance was significantly increased (+44%; p < .05). In these volunteers, muscle activation caused no significant effect at 90 degrees of abduction. However, in the 10 patients with impingement syndrome, muscle activity led to a significant decrease in the width of the subacromial space compared with that of the healthy contralateral side (-68%; p < .05). CONCLUSION: Muscle activity and arm position were found to cause systematic changes in the width of the subacromial space. However, functional deficits of the supraspinous muscle in patients with early-stage impingement syndrome were not apparent during muscle relaxation. 相似文献
27.
Heldenberg D Levtov O Eckstein N Barns L Getter R Tamir I 《Clinical nutrition (Edinburgh, Scotland)》1983,2(2):73-77
The fatty acid (FA) relative concentration (g/100g) of human milk triglyceride (TG) was compared to that of adipose tissue (AT). A high concentration of linoleic acid (C-18:2) was present in AT, probably reflecting long term high linoleic acid dietary intake. Linoleic acid was slightly lower in colostrum and transitional milk. No difference in C-18:2 relative concentration was seen between AT and human milk obtained 6 weeks post-partum. Marked short-term dietary modification in linoleic acid intake of the mother, 6 weeks post-partum, did not result in changes in C-18:2 relative concentration of human milk. In spite of measured marked intradiurnal variability in C-18:2 intake, human milk TG FA relative concentration remained remarkably constant. It is suggested that human milk TG FA composition reflects, mainly, the composition of AT. With the increased dietary intake of polyunsaturated fat in many populations, high levels of linoleic acid in human milk are to be expected. The intake of this fatty acid may exceed the suggested daily allowance and thus cause harmful effects, particularly in preterm infants. 相似文献
28.
Eckstein HH Kraus T Schumacher H Seelas R Allenberg JR 《Zentralblatt für Chirurgie》2000,125(3):259-269
Restoration of blood flow to reperfuse ischemic but not infarcted areas of the brain (ischemic penumbra) and the removal of an ongoing embolic source are the therapeutic aims of emergency and urgent carotid endarterectomy (CEA), both in patients with an acute or progressive ischemic stroke and in patients in the early period after a carotid-related stroke. Based on poor results in the 60ies and 70ies, many centers traditionally perform CEA four to six weeks after a carotid-related stroke at the earliest interval. Since natural history is associated with a high risk of an disabling and/or recurrent stroke in several subgroups of patients, some reports were able to show that urgent and emergency CEA could be worthwhile in well-selected patients. 相似文献
29.
Over a period of 4 years, 39 children with lymphadenitis were treated surgically; in 31 cases cervical lymph nodes were the main location. In 9 cases the lymphadenitis was caused by mycobacterial infection.Staphylococcus aureus was the most frequent causative organism of unspecific lymphadenitis (11 cases). The therapy of choice appears to be surgical treatment and medical care after operation. Especially in mycobacterial lymphadenitis, complete surgical excision of the lymph node is decisive for definitive healing. There was only 1 case of therapy-resistant, relapsing cervical lymphadenitis that needed a second operation. Causative organisms in this case wereMycobacterium avium andMycobacterium intracellulare. All other patients showed an uneventful postoperative clinical course. We believe that a consequent diagnostic process and cooperation between the pediatric surgeon and pediatrician are necessary for effective therapy. 相似文献
30.
Jeffrey P. Krischer Rashmi Gopal-Srivastava Stephen. C. Groft David J. Eckstein for the Rare Diseases Clinical Research Network 《Journal of general internal medicine》2014,29(3):739-744
Established in 2003 by the Office of Rare Diseases Research (ORDR), in collaboration with several National Institutes of Health (NIH) Institutes/Centers, the Rare Diseases Clinical Research Network (RDCRN) consists of multiple clinical consortia conducting research in more than 200 rare diseases. The RDCRN supports longitudinal or natural history, pilot, Phase I, II, and III, case–control, cross-sectional, chart review, physician survey, bio-repository, and RDCRN Contact Registry (CR) studies. To date, there have been 24,684 participants enrolled on 120 studies from 446 sites worldwide. An additional 11,533 individuals participate in the CR. Through a central data management and coordinating center (DMCC), the RDCRN’s platform for the conduct of observational research encompasses electronic case report forms, federated databases, and an online CR for epidemiological and survey research. An ORDR-governed data repository (through dbGaP, a database for genotype and phenotype information from the National Library of Medicine) has been created. DMCC coordinates with ORDR to register and upload study data to dbGaP for data sharing with the scientific community. The platform provided by the RDCRN DMCC has supported 128 studies, six of which were successfully conducted through the online CR, with 2,352 individuals accrued and a median enrollment time of just 2 months. The RDCRN has built a powerful suite of web-based tools that provide for integration of federated and online database support that can accommodate a large number of rare diseases on a global scale. RDCRN studies have made important advances in the diagnosis and treatment of rare diseases. 相似文献