全文获取类型
收费全文 | 5525篇 |
免费 | 569篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 143篇 |
儿科学 | 198篇 |
妇产科学 | 156篇 |
基础医学 | 739篇 |
口腔科学 | 121篇 |
临床医学 | 621篇 |
内科学 | 1080篇 |
皮肤病学 | 71篇 |
神经病学 | 340篇 |
特种医学 | 476篇 |
外科学 | 694篇 |
综合类 | 207篇 |
一般理论 | 2篇 |
预防医学 | 502篇 |
眼科学 | 123篇 |
药学 | 400篇 |
中国医学 | 6篇 |
肿瘤学 | 265篇 |
出版年
2023年 | 59篇 |
2022年 | 43篇 |
2021年 | 97篇 |
2020年 | 90篇 |
2019年 | 96篇 |
2018年 | 129篇 |
2017年 | 120篇 |
2016年 | 125篇 |
2015年 | 116篇 |
2014年 | 176篇 |
2013年 | 246篇 |
2012年 | 274篇 |
2011年 | 277篇 |
2010年 | 182篇 |
2009年 | 189篇 |
2008年 | 231篇 |
2007年 | 243篇 |
2006年 | 224篇 |
2005年 | 236篇 |
2004年 | 221篇 |
2003年 | 180篇 |
2002年 | 191篇 |
2001年 | 125篇 |
2000年 | 127篇 |
1999年 | 105篇 |
1998年 | 121篇 |
1997年 | 104篇 |
1996年 | 107篇 |
1995年 | 101篇 |
1994年 | 85篇 |
1993年 | 84篇 |
1992年 | 125篇 |
1991年 | 91篇 |
1990年 | 93篇 |
1989年 | 99篇 |
1988年 | 85篇 |
1987年 | 82篇 |
1986年 | 76篇 |
1985年 | 81篇 |
1984年 | 62篇 |
1983年 | 59篇 |
1982年 | 31篇 |
1980年 | 35篇 |
1979年 | 30篇 |
1978年 | 41篇 |
1977年 | 31篇 |
1976年 | 40篇 |
1975年 | 30篇 |
1974年 | 39篇 |
1973年 | 34篇 |
排序方式: 共有6144条查询结果,搜索用时 234 毫秒
31.
32.
A S Mark P Blake S W Atlas M Ross D Brown M Kolsky 《AJNR. American journal of neuroradiology》1992,13(5):1463-1470
PURPOSE: To describe a radiographic finding--enhancement of the cisternal portion of the third cranial nerve on postcontrast MR--and to correlate it with patients' clinical symptoms and ultimate diagnosis. MATERIALS AND METHODS: Thirteen consecutive patients with enhancement of the cisternal portion of the third cranial nerve on postcontrast MR were retrospectively identified; 50 control patients referred for pituitary microadenomas were also retrospectively reviewed. FINDINGS: The enhancement was bilateral in six patients and unilateral in seven patients. Four of the six patients with bilateral enhancement had unilateral oculomotor nerve palsies; none had bilateral third cranial nerve palsy. Five of the seven patients with unilateral enhancement had ipsilateral third nerve palsies. Of the nine patients with third nerve palsies, the pupil was involved in four patients. Follow-up studies were available in six patients, four of whom had third nerve palsy. Resolution of the enhancement correlated with resolution of the symptoms in two patients. The patients' underlying diagnoses were lymphoma (four), leukemia (one), viral meningitis (one), neurofibromatosis (two), inflammatory polyneuropathy-HIV related (one), ophthalmoplegic migraine (one), Tolosa-Hunt syndrome (one), coccidioidomycosis (one), and diabetes (one). No enhancement was seen in any of the controls. CONCLUSION: Enhancement of the cisternal segment of the third cranial nerve is always abnormal, revealing an underlying inflammatory or neoplastic process. However, it is not always associated with clinically apparent oculomotor nerve dysfunction. 相似文献
33.
Bastiaan R Klarenbeek Alexander AFA Veenhof Elly SM de Lange Willem A Bemelman Roberto Bergamaschi Piet Heres Antonio M Lacy Wim T van den Broek Donald L van der Peet Miguel A Cuesta 《BMC surgery》2007,7(1):16
Backround
Diverticulosis is a common disease in the western society with an incidence of 33–66%. 10–25% of these patients will develop diverticulitis. In order to prevent a high-risk acute operation it is advised to perform elective sigmoid resection after two episodes of diverticulitis in the elderly patient or after one episode in the younger (< 50 years) patient. Open sigmoid resection is still the gold standard, but laparoscopic colon resections seem to have certain advantages over open procedures. On the other hand, a double blind investigation has never been performed. The Sigma-trial is designed to evaluate the presumed advantages of laparoscopic over open sigmoid resections in patients with symptomatic diverticulitis. 相似文献34.
Strontium ranelate (SR) is a new oral treatment for osteoporosis associated with large increases in bone mineral density (BMD) compared with alternative therapies such as bisphosphonates. Much of the BMD increase during SR treatment is a physical effect caused by the increased attenuation of X-rays due to the accumulation of strontium in bone tissue. The aim of this study was to assess the contribution made by bone strontium content (BSC) to the overall BMD increase by evaluating the percentage F of the BMD change explained by the physical presence of strontium in bone. A value of F less than 100% would provide evidence of the anabolic effect of SR as an additional factor contributing to the overall BMD increase. Studies of mixtures of strontium hydroxyapatite (SrHA) and calcium hydroxyapatite (CaHA) scanned on a variety of dual-energy X-ray absorptiometry (DXA) systems show that a 1% molar ratio of SrHA/(CaHA+SrHA) causes a 10% overestimation of BMD. The correction of spine BMD measurements for the physical effects of strontium depends on knowledge of 2 further factors: (1) bone biopsy measurements of iliac crest BSC and (2) the ratio R of BSC at the DXA site to BSC at the iliac crest measured in animal studies. We used clinical trial data and values of R(spine) measured in studies of monkeys and beagle dogs to determine values of F(spine) for 1, 2, and 3 yr treatment with SR. Based on the average value of R(spine) approximately 0.7 for male and female monkeys, we found values for F(spine) approximately 75-80% for 1, 2, and 3 yr of treatment. Using the value of R(spine) approximately 1.0 from the beagle study gave values of F(spine) approximately 100%. Although values of F(spine) as low as 40% are possible, we conclude that the most likely figure is 75% or greater. However, it is apparent that there are large uncertainties in the correction of BMD results for the effect of bone strontium and that the most important of these is the inference of BSC values at DXA scan sites from measurements of iliac crest bone biopsy specimens. 相似文献
35.
36.
37.
38.
M. A. Sabin G. M. Blake S. M. MacLaughlin-Black I. Fogelman 《Calcified tissue international》1995,56(3):210-214
New developments in dual x-ray absorptiometry (DXA) allow the performance of high precision anteroposterior (AP) and lateral scans of spinal bone mineral density (BMD, units: g/cm2) without the patient moving from the supine position. Data from both projections may be combined to give an estimate of the true volumetric bone mineral density (VBMD, units: g/cm3) of the lumbar vertebral bodies. This report presents a cadaver study designed to validate DXA measurements of volumetric bone density. Sections of whole lumbar spine were scanned in AP and lateral projections in a water tank to simulate soft tissue. Individual vertebrae were then divided to separate the vertebral body from the neural arch, and vertebral body volume was measured using the displacement of sand. The bone mineral content (BMC) of vertebral bodies and neural arches was measured by ashing at 250°C for 60 hours followed by 500°C for a further 24 hours. The results showed that DXA scanning systematically underestimated ashing data by 14% for AP BMC, 33% for vertebral body BMC, 23% for vertebral body volume, and 12% for VBMD. Despite these significant systematic errors, the DXA measurements and ashing values were highly correlated (r=0.979-0.992). The results suggested that after allowing for the systematic errors, lateral DXA parameters related closely to true BMC, volume, and VBMD. 相似文献
39.
40.
P Blake G Abraham J Bargman S Vas R Mathews B Haberstroh D G Oreopoulos 《Peritoneal dialysis international》1989,9(1):73-74
A 26-year-old female was on continuous ambulatory peritoneal dialysis (CAPD) because of diabetic end-stage renal failure. She developed an acute peritonitis that relapsed repeatedly despite appropriate antibiotic treatment. Investigations showed the presence of a splenic abscess, and splenectomy and peritoneal cannula removal were required. The patient died of myocardial infarction two weeks postoperatively. This is the first recorded case of peritonitis secondary to splenic abscess in a CAPD patient. Autopsy findings suggest that the abscess developed from infection of a splenic infarct. 相似文献