全文获取类型
收费全文 | 612篇 |
免费 | 93篇 |
国内免费 | 10篇 |
学科分类
医药卫生 | 715篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 4篇 |
2019年 | 9篇 |
2018年 | 14篇 |
2017年 | 10篇 |
2016年 | 15篇 |
2015年 | 20篇 |
2014年 | 26篇 |
2013年 | 26篇 |
2012年 | 14篇 |
2011年 | 14篇 |
2010年 | 15篇 |
2009年 | 28篇 |
2008年 | 18篇 |
2007年 | 31篇 |
2006年 | 17篇 |
2005年 | 18篇 |
2004年 | 23篇 |
2003年 | 19篇 |
2002年 | 19篇 |
2001年 | 21篇 |
2000年 | 15篇 |
1999年 | 26篇 |
1998年 | 29篇 |
1997年 | 23篇 |
1996年 | 29篇 |
1995年 | 18篇 |
1994年 | 25篇 |
1993年 | 16篇 |
1992年 | 10篇 |
1991年 | 13篇 |
1990年 | 15篇 |
1989年 | 16篇 |
1988年 | 17篇 |
1987年 | 17篇 |
1986年 | 14篇 |
1985年 | 12篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 1篇 |
1978年 | 4篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有715条查询结果,搜索用时 781 毫秒
51.
R H Mohiaddin D G Lowell R S Underwood D N Firmin S Rees D B Longmore 《Journal of computer assisted tomography》1991,15(4):697-699
A case of suspected femoral arteriovenous fistula after cardiac catherization remained undiagnosed because of inability to obtain access for arteriography. Magnetic resonance imaging with phase-shift velocity mapping allowed a noninvasive diagnosis and qualitative evaluation of the lesion. 相似文献
52.
53.
Magnetic resonance (MR) imaging was performed on 14 patients with histologically proved osteosarcoma (mean age, 14.4 years). There was excellent correlation of intramedullary tumor extent as determined with MR imaging and pathologic examination (r = 99%). This was facilitated by the presence of a chemical shift artifact at the tumor-marrow interface on the T1-weighted images. The correlation between CT and pathologic findings was not as good (r = 84%). In a single patient, however, a 10-cm length of sclerotic bone was incorrectly interpreted as being tumor. If this case is excluded, the correlation between CT and pathologic findings improves significantly (r = 96%). T2-weighted images were optimal in demonstrating soft-tissue bulk and breach of the epiphysis or cortex. Vascular involvement was also readily defined. The T2 value of the tumor soft-tissue component decreased in patients who were deemed to have responded well to therapy. Two patients with very high T2 values after chemotherapy developed wide-spread metastatic disease and died. Phosphorus-31 MR spectroscopy of five patients with osteosarcoma showed elevated levels of phosphomonoesters (PMEs), inorganic phosphate (Pi), and phosphodiesters (PDEs). PME and PDE peak areas decreased in three patients after chemotherapy, while Pi peak areas increased. 相似文献
54.
Pedro Ferreira Peter Gatehouse Chiara Bucciarelli‐Ducci Ricardo Wage David Firmin 《Magnetic resonance in medicine》2008,60(4):860-870
MRI of myocardial perfusion observed with an extracellular contrast agent has proven valuable for the detection of coronary artery disease. During contrast enhancement transient dark rim artifacts are sometimes visible, complicating diagnosis and quantification. In this work a quantification of the frequency offsets caused solely by the first pass of Gd‐DTPA in a typical perfusion setup was made in vivo and compared with both phantom work and numerical simulations data. The results show that numerically simulated and phantom data agree well with in vivo frequency offsets. During the first pass main field distortion occurs mainly in the subendocardium, and the same pattern is always observed: positive for posterior/anterior regions, negative for septal/lateral regions (from ?69 to 85 Hz). The larger myocardial frequency offsets were measured for patients with greater angles between the long axis of the heart and the direction of the main field. From these results it would appear that the frequency offsets are too weak to cause dark rim artifacts due simply to intravoxel dephasing in a typical perfusion sequence. However, when added to other sources of off‐resonance it can cause dark rims in particular regions of the myocardium wall in balanced‐SSFP sequences. Magn Reson Med 60:860–870, 2008. © 2008 Wiley‐Liss, Inc. 相似文献
55.
While avid accumulation of gallium-67 citrate and technetium-99m methylene diphosphonate (MDP) occurs initially in most cases of primary Ewing sarcoma, uptake after therapy is less well defined. Thirty patients with Ewing sarcoma who underwent Ga-67 and bone scintigraphy at diagnosis, at completion of therapy, and at relapse from 1978 to 1988 were evaluated. All 30 patients showed less primary site Ga-67 activity following therapy. Twenty-three of 28 patients who underwent corresponding bone scintigraphy showed less uptake, but residual activity was usually more intense than with Ga-67. Avid reaccumulation of Ga-67 occurred in four of five patients with primary site relapse, while patients who underwent bone scintigraphy showed less change. It was concluded that a greater decrease in Ga-67 than in Tc-99m MDP uptake often occurs in patients successfully treated for primary Ewing sarcoma. Information obtained at Ga-67 scintigraphy is most likely to be helpful if results of bone scintigraphy remain abnormal or if occult relapse is suspected. 相似文献
56.
Patricia Ann Firby MSc DipEd RGN RCNT RNT DipNurs Lecturer Karen A Luker PhD BNurs RGN RHV DN Cert Professor of Community Nursing Ann-Louise Caress BNurs RGN RHV DN Cert Research Assistant 《Journal of advanced nursing》1991,16(8):987-995
Computers have only recently begun to find a place in the everyday work of health care staff. The use of computer-assisted learning (CAL) in patient education is in its infancy. However, the medium appears to offer several advantages to patients. The successful integration of the medium into clinical practice requires the acceptance and support of staff members. Little research exists to date which examines staff responses to the introduction of CAL into their workplace. This small study (n = 14) aims to explore the reactions of staff to the introduction of an experimental CAL package for use in the education of renal patients on continuous ambulatory peritoneal dialysis (CAPD). The opinions of staff members to CAL are probed and their views ascertained regarding the usefulness of CAL to both staff and patients. Results suggest that, despite their initial reservations about CAL, staff were generally positive about the medium. 相似文献
57.
Image processing and volume rendering have been applied to magnetic resonance (MR) images to produce three-dimensional views of the surface of the brain. Four healthy volunteers and 17 patients with a variety of disorders underwent MR imaging of the head, and these images were processed and subjected to volume rendering. The resulting three-dimensional views depict abnormalities of the brain surface, as well as important landmarks of normal brain surface anatomy such as precentral, postcentral, superior temporal, and inferior frontal gyri, which are difficult to identify on cross-sectional images. 相似文献
58.
59.
目的:严重的多节段脊髓型颈椎病单纯前路或后路手术都有其局限性。观察一期前后路联合手术并自体髂骨植骨及带锁钢板内固定材料置入在治疗多节段脊髓型颈椎病中的应用价值。方法:选择2004-11/2006-12本院12例多节段脊髓型颈椎病患者,均采用一期前后路减压、自体髂骨植骨融合、带锁钢板内固定联合手术。其中男9例,女性3例,年龄49~75岁;3节段受累9例,4节段受累3例(突出节段分布:C3~66例,C4~73例,C3~73例)。全部病例进行临床随访,患者均对本试验知情同意。采用mJOA评分标准对患者神经功能改善情况进行评定;术前颈椎侧位片测量,以D值(C4椎体后下缘到齿突后缘与C7椎体后下缘连线的垂直距离)评价颈椎(C2~7)弧度;根据颈椎伸屈动态侧位片C2和C7椎体后缘切线相交所成的夹角之和评价颈椎(C2~7)活动范围。主要以电话随访和问卷填写的方式,分别从神经功能改善情况、颈椎弧度、活动范围及术后并发症等进行随访观察。结果:①12例患者全部得到随访,术后随访时间6~28个月,平均(16±6)个月。②所有植骨均获得骨性愈合;疗效结果中优4例(33.3%);良6例(50%);无效2例(16.7%);颈椎D值术前(3.9±1.4)mm,术后即刻(8.5±1.7)mm,随访时(8.1±2.5)mm。术前与术后差异有显著性(P<0.01),术后与随访时差异无显著性(P=0.251);颈椎活动范围术前(36.3±4.0)°,随访时(10.6±2.7)°,与术前相比差异具有显著性(P<0.01)。③术后C5神经根麻痹1例,为感觉及运动混合型,8个月随访时,感觉功能恢复,肩关节外展肌力从术后Ⅱ级恢复至Ⅳ级;1例术后6个月出现"S"畸形而再次压迫脊髓,神经功能改善停滞,目前处于随访中。结论:一期前后路手术并自体髂骨植骨及带锁钢板内固定材料置入减压充分、彻底,而且前路手术能重建颈椎稳定性,恢复颈椎生理前凸和椎间高度,并且后路减压术又能预防相邻颈椎退变引起的脊髓继发的压迫。 相似文献
60.
Sandra Baulcomb BA MSc RGN RM DN PWT RDNT CertEd Roger Watson BSc PhD RGN CBiol FIBiol ILTM FRSA 《Clinical Effectiveness in Nursing》2003,7(3-4):168
The development of instruments to measure clinical competence in nursing shows little evidence of a systematic approach and studies of reliability and validity are absent. The present study was carried out using data on practice assessment collected in the course of a post-registration nursing programme. The data were analysed for internal consistency and intra-rater reliability. The instrument used to assess practice in the present study is highly internally consistent and there is evidence to support intra-rater reliability. However, further development and testing of the instrument is required. 相似文献