全文获取类型
收费全文 | 1782篇 |
免费 | 57篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 47篇 |
儿科学 | 119篇 |
妇产科学 | 99篇 |
基础医学 | 153篇 |
口腔科学 | 56篇 |
临床医学 | 154篇 |
内科学 | 368篇 |
皮肤病学 | 61篇 |
神经病学 | 99篇 |
特种医学 | 114篇 |
外科学 | 351篇 |
综合类 | 17篇 |
预防医学 | 34篇 |
眼科学 | 26篇 |
药学 | 105篇 |
中国医学 | 5篇 |
肿瘤学 | 33篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 26篇 |
2021年 | 39篇 |
2020年 | 27篇 |
2019年 | 29篇 |
2018年 | 35篇 |
2017年 | 39篇 |
2016年 | 53篇 |
2015年 | 55篇 |
2014年 | 90篇 |
2013年 | 116篇 |
2012年 | 151篇 |
2011年 | 126篇 |
2010年 | 70篇 |
2009年 | 48篇 |
2008年 | 86篇 |
2007年 | 116篇 |
2006年 | 124篇 |
2005年 | 134篇 |
2004年 | 119篇 |
2003年 | 94篇 |
2002年 | 71篇 |
2001年 | 20篇 |
2000年 | 24篇 |
1999年 | 22篇 |
1998年 | 6篇 |
1997年 | 11篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1981年 | 1篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1969年 | 1篇 |
排序方式: 共有1841条查询结果,搜索用时 0 毫秒
961.
目的探讨超声灰度直方图对腮腺多形性腺瘤与腺淋巴瘤的鉴别诊断价值。方法对18例多形性腺瘤(PA)与13例腺淋巴瘤(AL)患者的术前超声图像进行灰度直方图分析,比较PA与AL组患者直方图的均值、方差、偏度、峰度及第1、10、50、90、99百分位数的差异。应用受试者工作特征(ROC)曲线计算各参数的鉴别诊断效能。结果 PA组的方差高于AL组,偏度和峰度值低于AL组,其差异具有统计学意义(P<0.05);但2组的均值、第1、10、50、90及99百分位数的差异均无统计学意义(P>0.05)。ROC曲线分析显示,峰度值最具鉴别诊断效能,曲线下面积(AUC)为0.744 (P=0.022),最佳临界值为1.71,敏感度为76.9%,特异度为61.1%,约登指数为0.380。方差的鉴别诊断效能、最佳临界值、敏感度、特异度及约登指数分别为0.735 (P=0.028)、864.94、72.2%、76.9%及0.491。结论超声灰度直方图对PA与AL具有一定的鉴别诊断价值。 相似文献
962.
963.
Atilla Icli Senol Tayyar Ercan Varol Fatih Aksoy Akif Arslan Ibrahim Ersoy Selahaddin Akcay 《Medical principles and practice》2013,22(3):270-273
Objectives
The aim of this study was to assess the mean platelet volume (MPV), an indicator of platelet activation in patients with infective endocarditis.Subjects and Methods
Twenty-nine patients with infective endocarditis and 29 healthy subjects were studied. Plasma MPV values in patients and control subjects were measured on admission and after 2 weeks of specific treatment of infective endocarditis.Results
The MPV was significantly higher among patients with infective endocarditis when compared with the control group (9.86 ± 1.1 vs. 8.0 ± 1.0 fl, respectively; p < 0.01). The MPV values of patients with infective endocarditis decreased significantly after treatment from 9.86 ± 1.1 to 7.86 ± 1.0 fl (p < 0.01). Total platelet counts increased significantly after treatment from 193.4 ± 96.5 × 109 to 243.7 ± 92.4 × 109 (p = 0.04).Conclusion
MPV values were higher in patients with infective endocarditis and decreased significantly after treatment. Elevated MPV values indicate that patients with infective endocarditis have increased platelet activation and infective endocarditis treatment decreases this platelet activation by decreasing MPV.Key Words: Mean platelet volume, Infective endocarditis, Thrombus, Vegetation 相似文献964.
cDNA Array Hybridization after Laser-Assisted Microdissection from Nonneoplastic Tissue 总被引:5,自引:0,他引:5 下载免费PDF全文
Ludger Fink Stephanie Kohlhoff Maria Magdalena Stein Jrg Hnze Norbert Weissmann Frank Rose Ercan Akkayagil Daniel Manz Friedrich Grimminger Werner Seeger Rainer Maria Bohle 《The American journal of pathology》2002,160(1):81-90
Differential gene expression can be investigated effectively by cDNA arrays. Because tissue homogenates result inevitably in an average expression of a bulk of different cells, we aimed to combine mRNA profiling with cell-type-specific microdissection. Using a polymerase chain reaction (PCR)-based preamplification technique, the expression profile was shown to be preserved. We modified the existing protocol enabling to apply the total amount of extracted RNA from microdissected cells. A mean amplification factor of nearly 1000 allowed to reduce the demand of initial RNA to approximately 10 ng. This technique was used to investigate intrapulmonary arteries from mouse lungs ( approximately 500 cell equivalents). Using filters with 1176 spots, three independent experiments showed a high consistency of expression for the preamplified cDNAs. These profiles differed primarily from those of total lung homogenates. Additionally, in experimental hypoxia-induced pulmonary hypertension, amplified cDNA from intrapulmonary vessels of these lungs was compared to cDNA from vessels dissected from normoxic lungs. Validation by an alternative method was obtained by linking microdissection with real-time polymerase chain reaction (PCR). As suggested by the array data, nine selected genes with different factors of up-regulation were fully confirmed by the PCR technique. Thus, a rapid protocol is presented combining microdissection and array profiling that demands low quantities of initial RNA to assess reliably cell-type-specific gene regulation even within nonneoplastic complex tissues. 相似文献
965.
In this work, the brain lesions that cause spontaneously hyperintense T1 signal on MRI were studied under seven categories. The first category includes lesions with hemorrhagic components, such as infarct, encephalitis, intraparenchymal hematoma, cortical contusion, diffuse axonal injury, subarachnoid hemorrhage, subdural and epidural hematoma, intraventricular hemorrhage, vascular malformation and aneurysm, and hemorrhagic neoplasm. The second category includes protein-containing lesions, such as colloid cyst, craniopharyngioma, Rathke's cleft cyst, and atypical epidermoid. The third category includes lesions with fatty components, such as lipoma, dermoid, and lipomatous meningioma. Lesions with calcification or ossification, such as endocrine-metabolic disorder, calcified neoplasm, infection, and dural osteoma, constitute the fourth category, whereas the fifth category includes lesions with other mineral accumulation, such as acquired hepatocerebral degeneration and Wilson disease. The sixth category includes melanin-containing lesions, such as metastasis from melanoma and leptomeningeal melanosis. The last category is the miscellaneous group, which includes ectopic neurohypophysis, chronic stages of multiple sclerosis, and neurofibromatosis type I. The above-mentioned lesions are presented with their typical T1-hyperintense images, and the underlying reasons for those appearances in magnetic resonance imaging are discussed. 相似文献
966.
OBJECTIVE: It has recently been described that perirolandic cortex generally had a low signal intensity (SI) in neurologically normal brain. The aim of this study was to confirm this finding by an objective quantitative study. MATERIALS AND METHODS: Turbo fluid attenuated inversion recovery (FLAIR) magnetic resonance (MR) images of 24 neurologically normal patients were evaluated retrospectively. Signal intensity measurements of the precentral and superior frontal cortices (SFCs) were obtained at a manually traced irregular region-of-interest (ROI). t-Test for paired samples was used to evaluate the significance of differences between signal intensity measurements. RESULTS: Mean signal intensities of precentral and superior frontal cortices were 349.5 and 380.7, respectively, on the right, and 351.7 and 374.1 on the left hemisphere. The difference between the mean signal intensities of the side-matched precentral and superior frontal cortices was statistically significant (P < 0.001). CONCLUSION: Low signal intensity of the precentral cortex (PCC) in normal brain on turbo FLAIR images is an objective finding, confirmed by ROI measurement. 相似文献
967.
Erentuğ V Bozbuğa N Omeroğlu SN Ardal H Eren E Güçlü M Güzelmeriç F Kirali K Akinci E Yakut C 《Annals of vascular surgery》2003,17(6):682-685
Behçets disease is a systemic disease of unknown etiology with a chronic relapsing course, characterized by oral aphtous, genital ulcers, ocular lesions, and occasionally vasculitis. Major asymptomatic vascular complications should always be considered in patients with Behçets disease. We present the surgical treatment of two male Behçets patients of 41 and 30 years of age with ruptured infrarenal abdominal aortic aneurysms. The urgent repairs of ruptured abdominal aortic aneurysms were performed successfully in both patients. Because Behçets disease is usually seen at young ages, vascular assessment should also be done routinely for early diagnosis and therapy, which can be life-saving. 相似文献
968.
Osteophyte-induced dysphagia: report of three cases 总被引:3,自引:0,他引:3
Ozgocmen S Kiris A Kocakoc E Ardicoglu O 《Joint, bone, spine : revue du rhumatisme》2002,69(2):226-229
Dysphagia is a common complaint of patients seen by physicians. Osteophyte compression due to diffuse idiopathic skeletal hyperostosis (DISH) or Forestier's disease and cervical spondylosis has been identified as a cause of dysphagia. We report three elderly male cases of whom two had dysphagia due to DISH and one had dysphagia due to osteophyte compression associated with severe cervical spondylosis. Clinical and radiographical findings including barium oesophagogram and computed tomography are presented. Endoscopy should be carefully performed to rule out additional pathology in such patients. Medical treatment preferably with liquid forms of NSAIDs and diet may cause satisfactory improvement. 相似文献
969.
PURPOSE: The role of melatonin on chronic water avoidance stress (WAS) induced degeneration of bladder epithelium (urothelium) was investigated. MATERIALS AND METHODS: Wistar albino rats were exposed to WAS for 2 hours daily for 5 days (WAS group). Before exposing them to WAS 10 mg/kg melatonin (WAS plus melatonin group) was injected intraperitoneally into the animals. Bladder samples were investigated with light and electron microscopy. Lipid peroxidation and glutathione levels were also measured in the bladder. RESULTS: In the WAS only group an increased number of mast cells in the mucosa, ulcerated areas, vacuole formation and dilated perinuclear cisternae, and dilatation in the intercellular spaces in the urothelium were observed. In the WAS plus melatonin group relatively normal urothelial topography, a decreased number of mast cells in the mucosa, some dilatation between intercellular areas, regular perinuclear cisternae and tight junctions were observed. Increased lipid peroxidation and decreased glutathione levels in WAS rats were reversed by melatonin. CONCLUSIONS: The results show that melatonin reverses WAS induced degenerative changes in the bladder. 相似文献
970.