全文获取类型
收费全文 | 491篇 |
免费 | 47篇 |
国内免费 | 18篇 |
专业分类
儿科学 | 15篇 |
妇产科学 | 5篇 |
基础医学 | 72篇 |
口腔科学 | 14篇 |
临床医学 | 45篇 |
内科学 | 122篇 |
皮肤病学 | 5篇 |
神经病学 | 26篇 |
特种医学 | 111篇 |
外科学 | 65篇 |
综合类 | 3篇 |
预防医学 | 25篇 |
眼科学 | 3篇 |
药学 | 18篇 |
中国医学 | 2篇 |
肿瘤学 | 25篇 |
出版年
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 13篇 |
2017年 | 9篇 |
2016年 | 10篇 |
2015年 | 10篇 |
2014年 | 12篇 |
2013年 | 20篇 |
2012年 | 21篇 |
2011年 | 15篇 |
2010年 | 27篇 |
2009年 | 19篇 |
2008年 | 19篇 |
2007年 | 23篇 |
2006年 | 16篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 14篇 |
2002年 | 4篇 |
2001年 | 7篇 |
2000年 | 13篇 |
1999年 | 6篇 |
1998年 | 15篇 |
1997年 | 17篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 13篇 |
1993年 | 18篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 11篇 |
1989年 | 18篇 |
1988年 | 20篇 |
1987年 | 16篇 |
1986年 | 11篇 |
1985年 | 12篇 |
1984年 | 5篇 |
1983年 | 11篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1977年 | 12篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1964年 | 2篇 |
排序方式: 共有556条查询结果,搜索用时 31 毫秒
71.
Plantar fasciitis is a relatively common injury that occurs in running athletes. The disease entity is a good example of an overloaded process of the plantar fascia at its calcaneal insertion. This study was designed to examine the strength and flexibility findings in the muscles that are put on tensile load during running, and which are responsible for controlling the forces on the foot during stance and pushoff, thus modifying the overload. Three groups of athletes underwent physical examination, including checking ankle range of motion in plantar flexion and dorsiflexion. Cybex peak torque measurements were taken at 60 and 180 deg/sec. The groups were a control group of 45 athletes with no symptoms, a group that included 43 affected feet with symptomatic plantar fasciitis, and a group that included the 43 unaffected contralateral feet. Analysis of data showed dynamic range of motion deficits in 38 of 43 affected feet, static range of motion deficits in 37 of 43 affected feet, deficits in peak torque at 60 deg/sec in 41 of 43 affected feet, and deficits in peak torque at 180 deg/sec in 37 of 43 affected feet. Statistical comparison of range of motion showed that the group with symptomatic plantar fasciitis was significantly restricted compared to both control and unaffected contralateral feet groups. Statistical comparison of peak torque showed that the symptomatic plantar fasciitis group was significantly lower than both other groups at both velocities. This study documents strength and flexibility deficits in the supporting musculature of the posterior calf and foot that are affected by plantar fasciitis.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
72.
A polymer system was developed for use in permanent inflation of detachable balloons, to avoid long-term reliance on the integrity of balloon shells or valve mechanisms. This system is based on 2-hydroxy-ethyl methacrylate (HEMA) as the monomer, in combination with a cross-linking agent and a water-soluble curing system. The low-viscosity, hydrophilic mixture can be exchanged through a small-bore catheter into a detachable balloon and polymerizes in 40-60 minutes at body temperature. Partially polymerized HEMA can cause vascular occlusion; hence, careful timing of balloon detachment is required. The evolution of the radiographic appearance of HEMA-filled balloons is predictable. The balloons remain radiopaque on plain radiographs as long as the balloon shell and valve mechanisms are competent. After rupture of the shell or failure of the valve mechanism, the balloons become invisible on plain radiographs but remain hyperattenuating on computed tomography scans. 相似文献
73.
74.
Turner DA; Alcorn FS; Shorey WD; Stelling CB; Mategrano VC; Merten CW; Silver B; Economou SG; Straus AK; Witt TR 《Radiology》1988,168(1):49-58
Detectability of breast cancer with magnetic resonance (MR) imaging versus xeromammography was quantitatively compared. MR images were obtained of breasts of 120 women who underwent xeromammography. T1 values were determined for masses larger than 2 cm. Cancer was histologically confirmed in 39 breasts and was considered excluded from 81 due to results of biopsy, cyst aspiration, or sonography or absence of change in xeromammographic findings over time. Images were blindly interpreted by three observers, and results were expressed as receiver operating characteristic curves. Detectability of breast cancer was substantially better with xeromammography than with MR imaging for all observers (P less than .03, 10(-6), and .001). On MR images, spiculation of a mass, distorted architecture, skin thickening, and nipple or skin retraction were specific but relatively insensitive indicators of cancer. Masses with smooth, distinct margins and signal intensity greater than that of fat on T2-weighted images were always benign. Other findings and T1 values were not diagnostically useful. The authors conclude that xeromammography is superior to MR imaging in detection of breast cancer. 相似文献
75.
76.
Scrotal masses with a uniformly hyperechoic pattern 总被引:3,自引:0,他引:3
77.
The larger bronchi in cryptogenic fibrosing alveolitis: a morphometric study 总被引:2,自引:0,他引:2 下载免费PDF全文
In a morphometric study of the main, lobar, and segmental bronchi of the left lung in nine cases of cryptogenic fibrosing alveolitis the quantity of gland was found to be significantly greater than in a group of normal controls, and similar to that of a group of patients with chronic bronchitis. The quantity of muscle was also increased, amounts in the segmental bronchi being higher than in the bronchitic patients. The cause of these changes is uncertain, but they seem likely to be due to proximal extension of repeated and persistent infection of the lung parenchyma. 相似文献
78.
ANTIBODY STUDIES IN RABBIT ENCEPHALOMYELITIS INDUCED BY A WATER-SOLUBLE PROTEIN FRACTION OF RABBIT CORD 总被引:4,自引:0,他引:4 下载免费PDF全文
A water-soluble protein fraction of nervous tissue was prepared by extraction of rabbit spinal cord with sodium citrate at pH 4.3. Characterization by nitrogen content and paper electrophoresis showed it to be a mixture of basic proteins. This extract demonstrated encephalitogenic activity when injected into rabbits. The most suitable technique for the measurement of serum antibody to the rabbit cord antigen proved to be the precipitation of antigen-antibody complexes by 40 per cent saturated ammonium sulfate. Antibody could not be demonstrated by the techniques of complement fixation, quantitative precipitation, and Ouchterlony plates. The early appearance of circulating antibody occurred almost exclusively in rabbits that subsequently developed EAE. Specificity of the antibodies for nervous tissue was demonstrated by appropriate blocking and adsorption experiments. 相似文献
79.
80.