全文获取类型
收费全文 | 938篇 |
免费 | 71篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 51篇 |
妇产科学 | 9篇 |
基础医学 | 108篇 |
口腔科学 | 21篇 |
临床医学 | 106篇 |
内科学 | 216篇 |
皮肤病学 | 14篇 |
神经病学 | 24篇 |
特种医学 | 177篇 |
外科学 | 86篇 |
综合类 | 39篇 |
预防医学 | 78篇 |
眼科学 | 4篇 |
药学 | 55篇 |
2篇 | |
肿瘤学 | 37篇 |
出版年
2022年 | 2篇 |
2021年 | 5篇 |
2019年 | 9篇 |
2018年 | 17篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 16篇 |
2013年 | 17篇 |
2012年 | 37篇 |
2011年 | 32篇 |
2010年 | 29篇 |
2009年 | 24篇 |
2008年 | 42篇 |
2007年 | 48篇 |
2006年 | 40篇 |
2005年 | 32篇 |
2004年 | 27篇 |
2003年 | 26篇 |
2002年 | 30篇 |
2001年 | 15篇 |
2000年 | 22篇 |
1999年 | 31篇 |
1998年 | 37篇 |
1997年 | 41篇 |
1996年 | 33篇 |
1995年 | 25篇 |
1994年 | 24篇 |
1993年 | 31篇 |
1992年 | 11篇 |
1991年 | 12篇 |
1990年 | 16篇 |
1989年 | 40篇 |
1988年 | 23篇 |
1987年 | 30篇 |
1986年 | 22篇 |
1985年 | 41篇 |
1984年 | 23篇 |
1983年 | 15篇 |
1982年 | 11篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 14篇 |
1976年 | 8篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1968年 | 2篇 |
1934年 | 2篇 |
排序方式: 共有1028条查询结果,搜索用时 515 毫秒
1.
V Allen PhD DW Ryan MB FRCA A Murray PhD FIPSM 《International journal of clinical practice》1994,48(3):125-129
SUMMARY Four specialised air mattresses had interface pressure measured under six body sites prone to pressure sores in 10 subjects, supine and sitting. The mattresses were the Clinirest (SSI) and FirstStep (KCI) continuous airflow mattress overlays, and Airwave (Pegasus) and Nimbus (Huntleigh) alternating pressure air mattresses. On the mattress overlays, average supine interface pressures were 2.33 kPa (scapula), 4.15 kPa (elbow), 1.94 kPa (sacrum) and 2.79 kPa (buttock), although they were higher at the occiput (7.97 kPa) and heel (11.7 kPa). The alternating pressure air mattresses had an average minimum interface pressure close to zero for three sites, rising to 4.28 kPa under the heel. Average maximum interface pressures were 8.61 kPa (occiput), 5.21 kPa (scapula), 4.90 (elbow), 4.85 kPa (sacrum), 4.61 kPa (buttock) and 13.2 kPa (heel). No accepted scientific method exists for comparing the two types of mattress. Our data suggest a clinical benefit at the occiput and heel (supine) in using an alternating pressure air mattress and a benefit in using a continuous airflow mattress overlay at other sites. 相似文献
2.
3.
Bone death in transient regional osteoporosis. 总被引:2,自引:0,他引:2
A 48-year-old man developed transient regional osteoporosis, with hip and later knee pain. He responded well to lumbar sympathectomy. The femur and tibia adjacent to the painful knee were osteoporotic, while the medial femoral condyle showed increased uptake in a bone scan. In the femoral condyle, bone histology showed areas of dead bone undergoing osteoclastic resorption, and increased bone formation. The tibial bone was histologically normal. The partial bone death in the distal femur suggests that the disorder may be related to both avascular necrosis of bone and reflex sympathetic dystrophy. 相似文献
4.
J. A. Dunstan J. Roper L. Mitoulas† P. E. Hartmann† K. Simmer S. L. Prescott 《Clinical and experimental allergy》2004,34(8):1237-1242
BACKGROUND: Breast milk contains many immunomodulatory factors (soluble CD14 (sCD14), IgA and cytokines) with the potential to influence infant immune development. OBJECTIVE: To determine if changes in breast milk omega-3 polyunsaturated fatty acid (n-3 PUFA) composition as a result of maternal dietary fish oil supplementation during pregnancy can modify levels of these immunological parameters in breast milk. METHOD: In a randomized controlled trial, 83 atopic women received either 4 g fish oil capsules (containing 3.7 g n-3 PUFA) (n = 40) or 4 g olive oil capsules (n = 43) from 20 weeks gestation until delivery. Breast milk was collected 3 days post-partum and fatty acids were analysed by gas liquid chromatography and IgA, sCD14 and cytokines (IL-5, IL-6, IL-10, TNF-alpha and IFN-gamma) were quantitated by ELISA or time resolved fluorescence (TRF). RESULTS: Omega-3 docosahexaenoic acid (DHA; 22:6n-3) and eicosapentaenoic acid (EPA; 20:5n-3) levels were significantly higher (P < 0.001) in breast milk from women supplemented with fish oil (n = 33, DHA mean 1.15%, SD 0.47% and EPA mean 0.16%, SD 0.07%) than in samples from the control group (n = 40, DHA mean 0.50%, SD 0.17% and EPA mean 0.05%, SD 0.02%). Breast milk arachidonic acid (AA; 20:4n-6) levels were significantly lower (P = 0.045) in the fish oil group (mean 0.55%, SD 0.12%) compared with the control group (mean 0.61%, SD 0.14%). Breast milk IgA was positively correlated with DHA (P = 0.046) and 22:5n-3 (P = 0.003), but inversely correlated with linoleic acid (LA; 18:2n-6) (P=0.034). Levels of sCD14 were also positively correlated with 22:5n-3 (P=0.009). Cytokines involved in IgA synthesis (IL-10 and IL-6) were also significantly correlated with both IgA and n-3 PUFA levels, although there were no differences in the levels of breast milk IgA, sCD14 or cytokines between study groups. CONCLUSION: Supplementation with fish oil during pregnancy significantly alters early post-partum breast milk fatty acid composition. omega-3 PUFA levels were positively associated with IgA and sCD14 levels, suggesting a relationship between fatty acid status and mucosal immune function. 相似文献
5.
Eleven radiologists appointed by the major radiological societies participated for the past 5 years in the development of the Health Policy Agenda for the American People. The Agenda is an action plan to address a wide variety of serious problems in medicine. The first phase involved establishment of 159 principles, broad value statements that were the foundation of the project. Phase 2 involved the development of policy proposals on 38 urgent issues for action in medical science; education; health resources; delivery mechanisms; evaluation, assessment, and control; and payment for services. These proposals are summarized in this report. The activities and recommendations of representatives for the field of radiology are described. The Agenda has been released, and an implementation phase has begun. It will likely be of great importance to the practice of radiology over the next decade. Important issues can be addressed by acting with the coalitions that are being formed from among the more than 150 participating organizations. 相似文献
6.
7.
8.
9.
E K Lancaster R A Evans S Kos E Hills C R Dunstan S Y Wong 《Journal of bone and mineral research》1989,4(4):507-514
Bone mineral content (BMC) was measured in the os calcis of 232 normal subjects aged 17-82 years. The mean reproducibility (coefficient of variation) of the measurement was 1.8%. Substantial bone loss occurred between the ages of 20 and 50 years, and in females the menopause was associated with additional bone loss. There was no significant difference in the rate of bone loss in females and males, but the mean BMC was greater at all ages in males than in females. We also compared os calcis BMC with spinal bone mineral density (BMD), measured by quantitative computed tomographic (CT) scanning, in 85 subjects: 33 were normal controls, 19 had osteoporosis defined by the presence of one or more pathological fractures, and in the remainder the CT examination was performed at the patient's request. Os calcis BMC correlated with spinal BMD in both females (r = 0.69, p less than 0.001) and males (r = 0.84, p less than 0.001). However, the os calcis BMC did not reliably predict spine values around the CT "fracture threshold" of 90-100 mg/cm3 and did not correlate with osteoporotic fracture as well as did spinal BMD. It is concluded that measurement of the os calcis BMC is of limited clinical usefulness for the early diagnosis of osteoporosis. 相似文献
10.