全文获取类型
收费全文 | 10083篇 |
免费 | 944篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 125篇 |
儿科学 | 401篇 |
妇产科学 | 164篇 |
基础医学 | 1342篇 |
口腔科学 | 183篇 |
临床医学 | 1161篇 |
内科学 | 1748篇 |
皮肤病学 | 113篇 |
神经病学 | 862篇 |
特种医学 | 655篇 |
外科学 | 1242篇 |
综合类 | 292篇 |
一般理论 | 8篇 |
预防医学 | 1068篇 |
眼科学 | 178篇 |
药学 | 753篇 |
中国医学 | 4篇 |
肿瘤学 | 762篇 |
出版年
2021年 | 109篇 |
2019年 | 109篇 |
2018年 | 133篇 |
2017年 | 109篇 |
2016年 | 113篇 |
2015年 | 144篇 |
2014年 | 174篇 |
2013年 | 302篇 |
2012年 | 382篇 |
2011年 | 394篇 |
2010年 | 291篇 |
2009年 | 246篇 |
2008年 | 334篇 |
2007年 | 399篇 |
2006年 | 381篇 |
2005年 | 363篇 |
2004年 | 340篇 |
2003年 | 301篇 |
2002年 | 325篇 |
2001年 | 261篇 |
2000年 | 305篇 |
1999年 | 236篇 |
1998年 | 229篇 |
1997年 | 187篇 |
1996年 | 205篇 |
1995年 | 162篇 |
1994年 | 138篇 |
1993年 | 140篇 |
1992年 | 239篇 |
1991年 | 247篇 |
1990年 | 243篇 |
1989年 | 279篇 |
1988年 | 268篇 |
1987年 | 257篇 |
1986年 | 232篇 |
1985年 | 191篇 |
1984年 | 159篇 |
1983年 | 141篇 |
1982年 | 118篇 |
1981年 | 110篇 |
1980年 | 113篇 |
1979年 | 133篇 |
1978年 | 115篇 |
1977年 | 103篇 |
1976年 | 107篇 |
1975年 | 112篇 |
1974年 | 123篇 |
1973年 | 107篇 |
1972年 | 84篇 |
1971年 | 80篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Pediatric prehospital care in urban and rural areas 总被引:5,自引:0,他引:5
There are limited data concerning pediatric prehospital care, although pediatric prehospital calls constitute 10% of emergency medical services activity. Data from 10,493 prehospital care reports in 11 counties of California (four emergency medical services systems in rural and urban areas) were collected and analyzed. Comparison of urban and rural data found few significant differences in parameters analyzed. Use of the emergency medical services system by pediatric patients increased with age, but 12.5% of all calls were for children younger than 2 years. Calls for medical problems were most common for patients younger than 5 years of age; trauma was a more common complaint in rural areas (64%, P = .0001). Frequency of vital sign assessment differed by region, as did hospital contact (P less than .0001). Complete assessment of young pediatric patients, with a full set of vital signs and neurologic assessment, was rarely performed. Advanced life support providers were often on the scene, but advanced life support treatments and procedures were infrequently used. This study suggests the need for additional data on which to base emergency medical services system design and some directions for education of prehospital care providers. 相似文献
43.
44.
45.
46.
Short-Ti inversion-recovery pulse sequence: analysis and initial experience in cancer imaging 总被引:2,自引:0,他引:2
Inversion recovery (IR), commonly considered a pulse sequence capable of producing T1-weighted images with excellent display of normal anatomy, is versatile: The null point and peak time provide a useful, succinct summary of the properties of IR and its capacity for producing both T1- and T2-weighted images. Shortening of the inversion time (TI) and creation of a short-TI inversion-recovery (STIR) pulse sequence increases sensitivity to malignancy and other abnormalities by making the effects of prolonged T1 and T2 on signal intensity additive and by nulling the signal from fat. The authors examined over 300 patients with various malignancies and compared STIR images with T1- and T2-weighted images obtained at 0.5 T. In 43 cases, signal-difference-to-noise ratios (SD/Ns) were calculated between tumor, fat, and muscle. In general, STIR images demonstrated tumor as a conspicuously high-intensity area in a background of muted, discernible anatomic detail. The good contrast achieved with STIR sequences between tumor and fat (SD/N = 18.1) and tumor and muscle (SD/N = 12.9) consolidated into a single image the information contained separately on T1- and T2-weighted images, which facilitates efficient detection and localization of malignancy. 相似文献
47.
48.
Residual bone-mineral density and muscle strength after fractures of the tibia or femur in children.
R C Henderson G J Kemp E R Campion 《The Journal of bone and joint surgery. American volume》1992,74(2):211-218
This study compared the bone-mineral density in the proximal part of the femur and the flexion and extension strength of the knee in the fractured and the non-fractured limbs after an uncomplicated fracture of the tibia or femur in children. Thirty-eight children, whose ages ranged from two to fifteen years at the time of the injury, were evaluated at an average of 2.3 years after the injury. The mean difference in bone-mineral density between the fractured and non-fractured limbs was 3.3 per cent (p = 0.004). There was no significant difference between the bone-mineral density of the limbs that had been immobilized for less than four weeks and that of the contralateral, non-fractured limbs. However, the mean difference between the bone-mineral density of the limbs that had been immobilized for more than eight weeks and that of the contralateral limbs was 4.3 per cent (p = 0.006). There was little or no relationship between the time since the injury and the difference in bone-mineral density between the two limbs of the patient at the intervals of follow-up that were studied. No residual weakness in flexion and extension of the knee was detected, and no relationship was established between the limb-to-limb differences in strength and the limb-to-limb differences in bone-mineral density. The residual bone-mineral deficit was found to be minimum after an uncomplicated fracture. This difference, while statistically significant, is unlikely to be clinically important in the long term. However, the fact that there was a deficit raises a potential concern for children who have more severe or repeated injuries. 相似文献
49.
50.
The use of biological markers in toxicology 总被引:1,自引:0,他引:1