全文获取类型
收费全文 | 3367080篇 |
免费 | 245309篇 |
国内免费 | 8412篇 |
专业分类
耳鼻咽喉 | 45365篇 |
儿科学 | 110925篇 |
妇产科学 | 94119篇 |
基础医学 | 479246篇 |
口腔科学 | 93821篇 |
临床医学 | 310831篇 |
内科学 | 658447篇 |
皮肤病学 | 78954篇 |
神经病学 | 276026篇 |
特种医学 | 128684篇 |
外国民族医学 | 964篇 |
外科学 | 495997篇 |
综合类 | 69055篇 |
现状与发展 | 7篇 |
一般理论 | 1447篇 |
预防医学 | 266028篇 |
眼科学 | 75950篇 |
药学 | 246059篇 |
12篇 | |
中国医学 | 6467篇 |
肿瘤学 | 182397篇 |
出版年
2019年 | 26434篇 |
2018年 | 36776篇 |
2017年 | 28340篇 |
2016年 | 32421篇 |
2015年 | 36826篇 |
2014年 | 50720篇 |
2013年 | 76913篇 |
2012年 | 102326篇 |
2011年 | 108554篇 |
2010年 | 64985篇 |
2009年 | 62480篇 |
2008年 | 101927篇 |
2007年 | 108438篇 |
2006年 | 109653篇 |
2005年 | 105762篇 |
2004年 | 101798篇 |
2003年 | 98113篇 |
2002年 | 94818篇 |
2001年 | 156292篇 |
2000年 | 159948篇 |
1999年 | 135101篇 |
1998年 | 39152篇 |
1997年 | 34967篇 |
1996年 | 35425篇 |
1995年 | 34078篇 |
1994年 | 31419篇 |
1993年 | 29473篇 |
1992年 | 106244篇 |
1991年 | 103127篇 |
1990年 | 99911篇 |
1989年 | 96440篇 |
1988年 | 88941篇 |
1987年 | 87163篇 |
1986年 | 82171篇 |
1985年 | 78306篇 |
1984年 | 58900篇 |
1983年 | 50242篇 |
1982年 | 29963篇 |
1981年 | 26933篇 |
1979年 | 53030篇 |
1978年 | 37962篇 |
1977年 | 32211篇 |
1976年 | 29791篇 |
1975年 | 31903篇 |
1974年 | 38018篇 |
1973年 | 36668篇 |
1972年 | 34516篇 |
1971年 | 32092篇 |
1970年 | 29860篇 |
1969年 | 28504篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Renal fibrosis and the origin of the renal fibroblast. 总被引:4,自引:0,他引:4
Many studies have determined that the extent of tubulointerstitialinvolvement, particularly fibrosis, correlates better with renalfunction than glomerular changes do, thus, the extent of tubulointerstitialdamage in any given renal biopsy has important implicationsfor the renal prognosis of the patient (summarized in [1]).Tubulointerstitial fibrosis is characterized by the accumulationof extracellular matrix components including collagen typesI, III, IV, proteoglycans and fibronectin. In recent years,much controversy has been created in the nephrology communityregarding the origin of matrix-producing cells in the kidney.Several possibilities exist, including activation of residentinterstitial fibroblasts, migrating haematopoietic or mesenchymalstem cells from the bone marrow, periadventitial cells and epithelialmesenchymaltransition (EMT) of tubular epithelial cells. This review summarizesrecent data indicating the possible origin of matrix-producingcells in the kidney, and illustrates from a clinical point of 相似文献
992.
D.A. Legemate P.M. Bossuyt 《European journal of vascular and endovascular surgery》2006,32(6):620-623
There is insufficient evidence that the surgical treatment of asymptomatic infrarenal aneurysms > 5.5 cm. is beneficial to patients. This is the result of serious complications of aneurysm surgery and the dearth of information from randomized trials. Based on evidence from the literature we defined scenarios and translated data into natural frequency trees to improve understanding of the uncertainty of help versus harm due to treatment of aneurysms. Our analysis shows that the majority of patients can expect little on longevity from surgery while they are at risk of dying from surgery or suffering from serious morbidity. We conclude that, as long as uncertainty persist, patients should be treated in hospitals that can show very low surgical mortality and major morbidity rates. To further resolve the problem of uncertainty randomized trials for larger aneurysms should be performed. Important issues to discuss are the lower and upper limits of the diameter of the aneurysms and the age and risk profiles of the patients to be included in such trials. 相似文献
993.
M Engelhardt P Bast N Jeblink W Lauer A Popovic H Eufinger M Scholz A Christmann A Harders K Radermacher K Schmieder 《Minimally invasive neurosurgery》2006,49(2):98-103
This study was performed to evaluate the surgical strategy in patients with calvarial tumours, in order to design and modify a robot-assisted trepanation system. A total of 75 patients underwent craniectomy for the treatment of calvarial tumours during the 10-year period from 1993 to 2002. The patients' complaints, the size, location and histology of the tumour, and the various cranioplasty techniques used were analysed retrospectively. In a second procedure several craniectomies at typical locations according to the study's results were performed in a laboratory setting using a hexapod robotic tool, constructed at the Helmholtz-Institute, RWTH Aachen University, and plastic model heads. The workflow was documented and the reproducibility and the accuracy of the procedure were registered. A total of 83 surgical procedures were performed on 75 patients. The majority (87 %) of lesions treated surgically were located in the frontal, temporal and anterior parts of the parietal region. Histological examination revealed benign lesions in 66 % of the patients and dural involvement in 46 %. According to these results craniectomies were performed using the robotic system. Mean positioning accuracy of the robotic system while milling was 0.24 mm, with a standard deviation of 0.04 mm, and maximum error under 1 mm. Craniectomies leaving a 1-mm layer of the tabula interna intact to ensure a healthy dura were performed in several regions successfully. The majority of calvarial tumours, requiring surgical treatment in our patients, were located in cosmetically relevant areas in which drilling can be carried out with the robotic trepanation system. Consequently, the surgical approach had to be planned carefully in order to achieve a good cosmetic outcome. 相似文献
994.
995.
996.
Robert A. Mischkowski Max J. Zinser Alexander C. Kübler Barbara Krug Ulrich Seifert Joachim E. Zller 《Journal of cranio-maxillo-facial surgery》2006,34(8):478-483
BACKGROUND: An augmented reality tool for computer assisted surgery named X-Scope allows visual tracking of real anatomical structures in superposition with volume rendered CT or MRI scans and thus can be used for navigated translocation of bony segments. METHODS: In a feasibility study X-Scope was used in orthognathic surgery to control the translocation of the maxilla after Le Fort I osteotomy within a bimaxillary procedure. The situation achieved was compared with the pre-operative situation by means of cephalometric analysis on lateral and frontal cephalograms. RESULTS: The technique was successfully utilized in 5 patients. Maxillary positioning using X-Scope was accomplished accurately within a range of 1mm. The tool was used in all cases in addition to the usual intra-operative splints. A stand-alone application without conventional control does not yet seem reasonable. CONCLUSION: Augmented reality tools like X-Scope may be helpful for controlling maxillary translocation in orthognathic surgery. The application to other interventions in cranio-maxillofacial surgery such as Le Fort III osteotomy, fronto-orbital advancement, and cranial vault reshaping or repair may also be considered. 相似文献
997.
Background
Both diabetes and obesity syndromes are recognized to promote lumbar vertebral instability, premature osteodegeneration, exacerbate progressive osteoporosis and increase the propensity towards vertebral degeneration, instability and deformation in humans. 相似文献998.
999.
For many parents stopping life-sustaining medical treatment on their dying infant is psychologically impossible. Dostoevsky's insights into human behavior, particularly the fact that individuals do not want the anxiety and guilt associated with responsibility for making difficult decisions, might change the way physicians approach parents for permission to withdraw life-prolonging medical interventions on dying infants. 相似文献
1000.
Intake of arsenic from water, food composites and excretion through urine, hair from a studied population in West Bengal, India. 总被引:4,自引:0,他引:4
To evaluate the main intake source of arsenic by the villagers from arsenic-affected families in Jalangi and Domkol blocks in Mushidabad district, West Bengal-India, we determined the concentrations of arsenic in tube-well water and in food composites, mainly including vegetables and cereals collected from the surveyed families which were cultivated in that region. The daily dietary intakes of arsenic by the villagers were estimated and the excretions of arsenic through urine and hair were determined. The arsenic concentrations in hair and urine of the studied population living in mild (2.78 microg/L), moderate (30.7 microg/L) and high (118 microg/L) arsenic-affected families were 133, 1,391 and 4,713 microg/kg and 43.1, 244 and 336 microg/L, respectively. The linear regressions show good correlations between arsenic concentrations in water vs hair (r(2)=0.928, p<0.001) and water vs urine (r(2)=0.464, p<0.01). Approximately 29.4%, 58.1% and 62.1% of adult population from mild, moderate and high arsenic-affected families were suffering from arsenical skin manifestations. The mean arsenic concentrations of food composites (vegetables and cereals) in high arsenic-affected families are not significantly different from mild arsenic-affected families. The daily dietary intakes of arsenic from water and food composites of the studied population, living in high, moderate and mild arsenic-affected families were 568, 228 and 137 microg, respectively. The linear regressions show good correlations between arsenic concentrations in hair vs daily dietary intake (r(2)=0.452, p<0.001) and urine vs daily dietary intake (r(2)=0.134, p<0.001). The water for drinking contributed 6.07%, 26.7% and 58.1% of total arsenic in our study from mild, moderate and high arsenic-affected families. The result suggested that the contaminated water from high arsenic-affected families should be the main source for intake of arsenic. On contrary, the contribution of arsenic-contaminated food composites from mild and moderate arsenic-affected families might be the main source for intake of arsenic. The Food and Agriculture Organization/World Health Organization (FAO/WHO) provisional tolerable weekly intake (PTWI) values of arsenic in our study were 3.32, 5.75 and 12.9 microg/kg body weight/day from mild, moderate and high arsenic-affected families, respectively, which is higher than the recommended PTWI value of arsenic (2.1 microg/kg body weight/day). 相似文献