首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   484篇
  免费   34篇
  国内免费   3篇
耳鼻咽喉   8篇
儿科学   21篇
妇产科学   20篇
基础医学   61篇
口腔科学   8篇
临床医学   45篇
内科学   91篇
皮肤病学   31篇
神经病学   34篇
特种医学   12篇
外科学   56篇
综合类   18篇
一般理论   1篇
预防医学   44篇
眼科学   14篇
药学   29篇
中国医学   1篇
肿瘤学   27篇
  2023年   12篇
  2022年   23篇
  2021年   25篇
  2020年   20篇
  2019年   27篇
  2018年   21篇
  2017年   15篇
  2016年   11篇
  2015年   23篇
  2014年   24篇
  2013年   28篇
  2012年   52篇
  2011年   41篇
  2010年   18篇
  2009年   24篇
  2008年   21篇
  2007年   20篇
  2006年   25篇
  2005年   24篇
  2004年   15篇
  2003年   13篇
  2002年   9篇
  2001年   7篇
  2000年   1篇
  1999年   3篇
  1998年   1篇
  1996年   1篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1984年   1篇
  1981年   1篇
  1980年   2篇
排序方式: 共有521条查询结果,搜索用时 15 毫秒
41.
42.
43.


Problem: Maternal mortality in Uganda has remained unchanged at 500/100 000 over the past 10 years despite concerted efforts to improve the standard of maternity care. It is especially difficult to improve standards in rural areas, where there is little money for improvements. Furthermore, staff may be isolated, poorly paid, disempowered, lacking in morale, and have few skills to bring about change.

Design: Training programme to introduce criteria based audit into rural Uganda.

Setting: Makerere University Medical School, Mulago Hospital (large government teaching hospital in Kampala), and Mpigi District (rural area with 10 small health centres around a district hospital).

Strategies for change: Didactic teaching about criteria based audit followed by practical work in own units, with ongoing support and follow up workshops.

Effects of change: Improvements were seen in many standards of care. Staff showed universal enthusiasm for the training; many staff produced simple, cost-free improvements in their standard of care.

Lessons learnt: Teaching of criteria based audit to those providing health care in developing countries can produce low cost improvements in the standards of care. Because the method is simple and can be used to provide improvements even without new funding, it has the potential to produce sustainable and cost effective changes in the standard of health care. Follow up is needed to prevent a waning of enthusiasm with time.

  相似文献   
44.
In this work, a fast digital device is defined, which is customized to implement an artificial neuron. Its high computational speed is obtained by mapping data from floating point to integer residue representation, and by computing neuron functions through residue arithmetic operations, with the use of table look-up techniques. Specifically, the logic design of a residue neuron is described and complexity figures of area occupancy and time consumption of the proposed device are derived. The approach was applied to the logic design of a residue neuron with 12 inputs and with a Residue Number System defined in such a way as to attain an accuracy better than or equal to the accuracy of a 20-bit floating point system. The proposed design (NEUROM) exploits the RNS carry independence property to speed up computations, in addition it is very suitable for using look-up tables. The response time of our device is about 8 x T(ACC), where T(ACC) is the ROM access time. With a value of T(ACC) close to the 10 ns allowed by the current ROM technology, the proposed neuron responds within 80 ns, NEUROM is therefore the neuron device proposed in the literature which allows for maximum throughput. Moreover, when a pipeline mode of operation is adopted, the pipeline delay can assume a value as low as about 14 ns. In the case study considered, the total amount of ROM is about 5.55 Mbits. Thus, using current technology, it is possible to integrate several residue neurons into a single VLSI chip, thereby enhancing chip throughput. The paper also discusses how this amount of memory could be reduced, at the expense of the response time.  相似文献   
45.
In dental traumatology, the loss of teeth and the supporting alveolar bone in children compromise the proper development of maxillofacial structures and also limit the solutions that can be offered. In this case report, multidisciplinary management is described of a child with a significant loss of alveolar bone and associated teeth due to a traffic accident at 8 years of age. The management involved staged teeth autotransplantation into surgically prepared sites with bone expanders, orthodontic treatment and dental implants. The 3D regeneration of the alveolar process was successfully stimulated by teeth autotransplantation. At the 4‐year follow‐up visit, evaluation of the autotransplanted teeth and the implants indicated a successful outcome for the patient.  相似文献   
46.
Mucopolysaccharidosis type I (MPS I) is an inherited lysosomal storage disease that seriously affects the brain. Severity of neurocognitive symptoms in attenuated MPS subtype (MPS IA) broadly varies partially, due to restricted permeability of blood‐brain barrier (BBB) which limits treatment effects of intravenously applied α‐L‐iduronidase (rhIDU) enzyme. Intrathecal (IT) rhIDU application as a possible solution to circumvent BBB improved brain outcomes in canine models; therefore, our study quantifies effects of IT rhIDU on brain structure and function in an MPS IA patient with previous progressive cognitive decline. Neuropsychological testing and MRIs were performed twice prior (baseline, at 1 year) and twice after initiating IT rhIDU (at 2nd and 3rd years). The difference between pre‐ and post‐treatment means was evaluated as a percentage of the change. Neurocognitive performance improved particularly in memory tests and resulted in improved school performance after IT rhIDU treatment. White matter (WM) integrity improved together with an increase of WM and corpus callosum volumes. Hippocampal and gray matter volume decreased which may either parallel reduction of glycosaminoglycan storage or reflect typical longitudinal brain changes in early adulthood. In conclusion, our outcomes suggest neurological benefits of IT rhIDU compared to the intravenous administration on brain structure and function in a single MPS IA patient. © 2017 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.  相似文献   
47.
Monocyte chemoattractant protein (MCP)-1 is upregulated in atherosclerotic plaques and in the media and intima of injured arteries. CC chemokine receptor 2 (CCR2) is the only known functional receptor for MCP-1. Mice deficient in MCP-1 or CCR2 have marked reductions in atherosclerosis. This study examines the effect of CCR2 deficiency in a murine model of femoral arterial injury. Four weeks after injury, arteries from CCR2(-/-) mice showed a 61.4% reduction (P<0.01) in intimal area and a 62% reduction (P<0.05) in intima/media ratio when compared with CCR2(+/+) littermates. The response of CCR2(+/-) mice was not significantly different from that of CCR2(+/+) mice. Five days after injury, the medial proliferation index, determined by bromodeoxyuridine incorporation, was decreased by 59.8% in CCR2(-/-) mice when compared with CCR2(+/+) littermates (P<0.05). Although leukocytes rapidly adhered to the injured arterial surface, there was no significant macrophage infiltration in the arterial wall of either CCR2(-/-) or CCR2(+/+) mice 5 and 28 days after injury. These results demonstrate that CCR2 plays an important role in mediating smooth muscle cell proliferation and intimal hyperplasia in a non-hyperlipidemic model of acute arterial injury. CCR2 may thus be an important target for inhibiting the response to acute arterial injury.  相似文献   
48.

Background

Limb loss occurs as a result of different causes and has been increasing in many countries. This study determines the demography of amputees in one of the relatively large cities of Iran.

Methods

This retrospective study was undertaken on all of the amputees between 2003 and 2011. Patients’ demographics including age, sex, the limb that had undergone amputation, etiology of limb loss and side and level of amputation were recorded. Also, the level of amputation was recorded as minor (below wrist or ankle) or major (above wrist or ankle).

Results

In total, 624 patients were enrolled in the study. The number of amputees was from 53 to 118/year. Of the patients, 508 were male (81.4?%) and 118 were female (18.6?%). The men with amputation were younger on average than women; 61.9?% of the amputations (386) were major and 38.1?% were minor (238). Overall, the most common cause of amputation was trauma and the most common level was transmetatarsal. The most common level for major amputations was below knee.

Conclusion

In contrast to similar studies in developed countries, trauma was found to be the major cause of all types of amputations and in all age groups, which emphasizes the need for preventive measures in the country.  相似文献   
49.
50.
A 70-year-old woman presented with an atypical erythematopapular zosteriform eruption of 3 weeks' duration. The patient had no history of previous vesicular eruption. She developed a painful burning sensation on the neck. Clinical examination revealed a cluster of small erythematous firm papules and plaques in a zosteriform distribution on the left ear, face, neck, and shoulder (Figure 1A). The lesions were unilateral and did not cross the midline. Multiple cervical and axillary lymph nodes were palpable. Laboratory tests revealed an increase in white blood cells of 25,000/mm3, with 17,910/mm3 lymphocytes and a normal range of hemoglobin, platelets, creatinine, and liver enzymes. Erythrocyte sedimentation rate was 87 mm. Blood smear results showed small, morphologically mature lymphocyte cells. In immune phenotyping, lymphocyte cells co-express CD5 and B-cell-surface antigens CD19 and CD23, as well as a restriction of kappa immunoglobulin light chains. The cells were CD22-, CD79b-, CD38-, CD10-, CD25- and FMC7-. Computed thoracoabominal tomography revealed cervical, mediastinal, abdominal, and pelvic adenopathy confirming the diagnosis of B-cell chronic lymphocytic leukemia (B-CLL) stage B. Histology of a skin biopsy from a papule showed a dense nodular granulomatous infiltrate in the dermis (Figure 2A). The infiltrate contained epithelioid and giant cells surrounded by lymphocytes and plasma cells. Small monomorphic lymphocytes without mitotic figures predominated (Figure 2B). The epidermis was irregularly thickened. Immunohistology revealed a polymorphous infiltrate with a phenotype of reactive T lymphocytes (CD3, CD5 positive) (Figure 2C), B lymphocytes (CD20 positive) (Figure 2D). Epithelioid and giant cells were positive for CD68 (Figure 2E). A latent herpes zoster infection with granulomatous reaction at the site ofzoster lesions was highly suspected as the patient reported a unilateral burning sensation without a history of vesicular zosteriform eruption. She received treatment with intravenous acyclovir 10 mg/kg every 8 hours. The papular lesions resolved markedly (60%) on macular plaques at the end of the treatment. Following topical treatment with corticosteroids, the lesions healed completely within 4 weeks (Figure 1B). Concerning leukemia, our patient was monitored without therapy by the hematologist.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号