全文获取类型
收费全文 | 1702篇 |
免费 | 95篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 155篇 |
妇产科学 | 17篇 |
基础医学 | 174篇 |
口腔科学 | 47篇 |
临床医学 | 156篇 |
内科学 | 389篇 |
皮肤病学 | 23篇 |
神经病学 | 33篇 |
特种医学 | 470篇 |
外科学 | 121篇 |
综合类 | 30篇 |
预防医学 | 54篇 |
眼科学 | 13篇 |
药学 | 54篇 |
中国医学 | 3篇 |
肿瘤学 | 80篇 |
出版年
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 18篇 |
2017年 | 10篇 |
2016年 | 22篇 |
2015年 | 27篇 |
2014年 | 27篇 |
2013年 | 60篇 |
2012年 | 26篇 |
2011年 | 27篇 |
2010年 | 78篇 |
2009年 | 61篇 |
2008年 | 44篇 |
2007年 | 31篇 |
2006年 | 32篇 |
2005年 | 31篇 |
2004年 | 23篇 |
2003年 | 21篇 |
2002年 | 21篇 |
2001年 | 14篇 |
2000年 | 24篇 |
1999年 | 26篇 |
1998年 | 133篇 |
1997年 | 118篇 |
1996年 | 124篇 |
1995年 | 91篇 |
1994年 | 74篇 |
1993年 | 81篇 |
1992年 | 22篇 |
1991年 | 21篇 |
1990年 | 15篇 |
1989年 | 59篇 |
1988年 | 44篇 |
1987年 | 49篇 |
1986年 | 45篇 |
1985年 | 47篇 |
1984年 | 24篇 |
1983年 | 31篇 |
1982年 | 34篇 |
1981年 | 20篇 |
1980年 | 36篇 |
1979年 | 14篇 |
1978年 | 15篇 |
1977年 | 17篇 |
1976年 | 23篇 |
1975年 | 24篇 |
1971年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有1820条查询结果,搜索用时 15 毫秒
991.
Dietary therapy practice in 18 British clinics for diabetic children is reviewed, and contrasted with Canadian and American practice. Values for dietary composition expressed as energy are presented for small groups of British and Canadian children. Fat is often the principal energy source in British diabetic children; protein intake is much higher in the Canadian. It is suggested that British practice might be improved by the adoption of a simple uniform exchange system. Reported differences in growth characteristics may reflect differences in protein intake. 相似文献
992.
993.
Three patients with transient episodes of hypotension following blunt abdominal trauma incurred in motor vehicle accidents were examined by computed tomography within 6 hours of injury. The examinations were done using a contrast material injection technique that ordinarily leads to greater splenic than hepatic attenuation. None of the patients had splenic injury evident on autopsy, surgery, or clinical follow-up study (one case each), nor did they have other characteristic features of splenic infarction. However, in each case the spleen was less enhanced than the liver, leading to an erroneous impression in one patient that the splenic artery had been disrupted. Physiologic studies have shown that splenic perfusion decreases with sympathetic stimulation; this may have been the cause of the diminished enhancement. Decreased splenic enhancement should be interpreted cautiously in traumatized hypotensive patients. 相似文献
994.
995.
The criteria for a diagnosis of loosening or infection of hip arthroplasties on arthrographic study were further refined by a retrospective review of 178 arthrograms representing 170 patients. The 97 arthroplasties that were surgically evaluated form the basis of this report. With the refined criteria, subtraction arthrography had a sensitivity of 96% and specificity of 92% for demonstrating loosening of the femoral component and a sensitivity of 97% and a specificity of 68% for demonstrating loosening of the acetabular component. Pseudocapsule size and the presence of bursae were important factors influencing arthrographic interpretation. Arthrographic findings of pseudocapsule irregularity and the presence of nonbursal cavities were suggestive of infection but were not sensitive or specific. Laboratory evaluation of aspirated material was a more reliable predictor of infection, although its sensitivity was only 71%. 相似文献
996.
Phantoms were used to compare imaging of various masses in the glandular region for two types of breasts. In one type, normal glandular tissue contains no fat clumps; in the other type, randomly distributed spherical fat clumps exist. The size distribution and number of fat clumps per unit volume in the phantoms represented those found in actual normal glandular tissue. For a 5-cm path length between the scanning window of the phantom and the centers of the masses, the presence of the fat clumps caused distortions and deviations of the beam, resulting in image distortion. This degradation was reduced when successive slabs of the material containing the fat clumps were removed. Image degradation appeared to be less severe when a 2.25 (rather than a 3.5) MHz transducer was used. The results show that the thickness of tissue containing fat clumps between the scanning transducer and a mass plays a role in the detectability of masses and diagnostic usefulness of the image of a breast. This suggests that imaging of the breast in the compressed configuration should be performed regardless of whether the freely suspended breast is imaged. Also, transducers of lower nominal frequency may have an important role in breast imaging. 相似文献
997.
Pitfall in MR imaging of lymphadenopathy after lymphangiography 总被引:3,自引:0,他引:3
In two patients examined with magnetic resonance (MR) imaging after lymphangiography, opacified pelvic lymph nodes could not be distinguished from subcutaneous or retroperitoneal fat because of the short T1 and long T2 relaxation times of lymphangiographic contrast media. Opacified nodes removed from one patient had relaxation times similar to those of fat. Thus, assessment of lymphadenopathy with MR imaging should be performed before lymphangiography to obviate this potential pitfall. 相似文献
998.
Telephone transfer of nuclear cardiology studies 总被引:1,自引:0,他引:1
Royal HD; Parker JA; Mandell CH; Uren RF; Chambers HM; Jansons D; Hyman RM; Kolodny GM 《Radiology》1983,147(2):590-591
999.
Fisher DA Martin C Galanko J Sandler RS Noble MD Provenzale D 《The American journal of gastroenterology》2004,99(10):2019-2024
OBJECTIVES: The goal of this study was to identify predictors of presenting with late-stage colorectal cancer with a focus on potentially modifiable factors. METHODS: This was a multicenter, case-based study of patients with colorectal cancer. Detailed information about the cancer was abstracted from the tumor registries, pathology reports, and medical records. The remaining information was obtained by telephone interview. Inclusion criteria were age 40-85 yr with a first diagnosis of histologically proven colorectal cancer between July 1, 1997 and January 1, 2001. Simple contingency table methods were used to examine the relationship between potential risk factors for early versus advanced-stage disease. Logistic regression was performed to simultaneously control for potential confounding factors. RESULTS: There was complete information for 549 respondents. Approximately, 43% of the sample presented with late-stage colorectal cancer. In univariate analysis, lacking a usual source of health care (doctor's office or clinic), no participation in any colorectal cancer screening test in the prior 10 yr, symptoms of blood in stool, and unexplained weight loss were associated with late-stage colorectal cancer. In the logistic regression model, only lacking a usual source of healthcare and unexplained weight loss were associated with late-stage colorectal cancer with odds ratios (95% confidence intervals) of 0.4 (0.2-0.6) and 1.9 (1.2-3.0), respectively. CONCLUSIONS: These results suggest that system changes in the VA health-care system that increase access to and improve utilization of primary care may reduce presentation with late-stage colorectal cancer and thus, reduce mortality from colorectal cancer in veterans. 相似文献
1000.