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   1422篇
  免费   116篇
  国内免费   9篇
耳鼻咽喉   28篇
儿科学   9篇
妇产科学   14篇
基础医学   233篇
口腔科学   31篇
临床医学   89篇
内科学   267篇
皮肤病学   93篇
神经病学   70篇
特种医学   73篇
外科学   271篇
综合类   15篇
一般理论   3篇
预防医学   78篇
眼科学   23篇
药学   94篇
中国医学   29篇
肿瘤学   127篇
  2023年   12篇
  2022年   33篇
  2021年   58篇
  2020年   39篇
  2019年   42篇
  2018年   70篇
  2017年   45篇
  2016年   59篇
  2015年   72篇
  2014年   82篇
  2013年   111篇
  2012年   150篇
  2011年   98篇
  2010年   55篇
  2009年   34篇
  2008年   80篇
  2007年   75篇
  2006年   67篇
  2005年   67篇
  2004年   64篇
  2003年   56篇
  2002年   40篇
  2001年   19篇
  2000年   15篇
  1999年   11篇
  1998年   3篇
  1997年   6篇
  1996年   7篇
  1995年   8篇
  1994年   3篇
  1993年   5篇
  1992年   7篇
  1991年   9篇
  1990年   7篇
  1989年   8篇
  1988年   2篇
  1987年   3篇
  1986年   5篇
  1985年   2篇
  1984年   6篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1975年   2篇
  1974年   2篇
  1973年   1篇
  1968年   2篇
  1944年   1篇
排序方式: 共有1547条查询结果,搜索用时 15 毫秒
81.
BACKGROUNDBezoar is a mass of hardened external material found in the gastrointestinal (GI) tract. It may form anywhere in the GI tract, but esophageal bezoar is rare because of the short esophageal transit time. Psyllium seed husk is an indigestible natural derivative that is widely used as an herbal laxative. Herein, we report a case of acute esophageal obstruction caused by a bezoar after ingestion of psyllium seed husk powder.CASE SUMMARYA 76-year-old male with Parkinson''s disease visited the emergency department with swallowing difficulty approximately 10 h after ingesting psyllium seed husk powder. Symptoms began a few hours after ingestion and progressed to severe dysphagia. There were no abnormal findings on simple radiography. However, a computed tomography scan revealed an approximately 2.0 cm × 2.5 cm mass located near the gastro-esophageal junction. After grinding, the mass was removed using an endoscopic capture net. Esophageal bezoars may cause life-threatening complications. Patients with Parkinson''s disease may have esophageal motility dysfunction, which may increase esophageal transit time. Since our patient had Parkinson''s disease, this effect may have contributed to the formation of the bezoar.CONCLUSIONAttention should be paid to using bulk-laxatives, and an appropriate specified regimen will be needed when marketed as a dietary supplement.  相似文献   
82.
83.
84.
85.
Vascular endothelial growth factor receptor (VEGFR)‐3, a receptor for VEGF‐C and VEGF‐D, is expressed in neural progenitor cells, but there has been no comprehensive study of its distribution in the developing brain. Here, the temporal and cell‐specific expression of VEGFR‐3 mRNA was studied in the developing rat forebrain and eye. Expression appeared along the ventricular and subventricular zones of the lateral and third ventricles showing ongoing neurogenesis as early as embryonic day 13 but was progressively down‐regulated during development and remained in the subventricular zone and rostral migratory stream of the adult forebrain. VEGFR‐3 expression was also detectable in some differentiating and postmitotic neurons in the developing cerebral cortex, including Cajal‐Retzius cells, cortical plate neurons, and subplate neurons. Expression in the subplate increased significantly during the early postnatal period but was absent by postnatal day 14. It was also highly expressed in nonneural tissues of the eye during development, including the retinal pigment epithelium, the retinal ciliary margin, and the lens, but persisted in a subset of cells in the pigmented ciliary epithelium of the adult eye. In contrast, there was weak or undetectable expression in the early neural retina, but a subset of retinal neurons in the postnatal and mature retina showed intense signals. These unique spatiotemporal mRNA expression patterns suggest that VEGFR‐3 might mediate the regulation of both neurogenesis and adult neuronal function in the rat forebrain and eye. J. Comp. Neurol. 518:1064–1081, 2010. © 2009 Wiley‐Liss, Inc.  相似文献   
86.
局部中晚期食管癌的多学科整合治疗   总被引:3,自引:0,他引:3  
虽然手术是局限性食管癌的主要治疗手段,但初诊时可行根治性手术治疗的患者仅占总数的30%~40%,且根治手术后患者5年总生存率仅为15%~20%;放射治疗是食管癌的另一种局部治疗手段,但仅接受单一放疗的局限性食管癌患者预后不佳.手术、放疗与化疗的联合应用目前被认为是提高食管癌根治疗效的重要途径.本文总结并分析了近年来局限性食管癌的多学科整合治疗的方法及疗效,并根据多项Ⅲ期临床研究及荟萃分析的结果提供以下治疗建议:临床Ⅰ期、ⅡA期的食管癌推荐直接给予根治性手术(除颈段食管癌);局部中晚期食管癌可考虑同期诱导放化疗后行根治性手术.以顺铂为基础的同期放化疗目前是无法手术的局部中晚期食管癌的推荐治疗手段.对已接受手术但肿瘤未被完全切除或手术切缘阳性者,应予以根治剂量的辅助同期放化疗.  相似文献   
87.
Mun GH  Song YH  Bang SI 《Annals of plastic surgery》2002,49(4):337-43; discussion 344
Full exposure of the medial orbital wall for fracture repair poses difficulty with traditional approaches except coronal incision, especially in cases of wide fracture. The endoscopic-assisted approach with limited incision has been introduced. The authors used the endoscopically assisted transconjunctival approach in 21 cases: 15 isolated medial orbital wall fractures and 6 cases of concomitant floor fractures. Through the medial transconjunctival slit incision, repair of the fracture using calvarial bone graft was undertaken with the aid of an endoscope. All patients recovered without any eye symptoms including clinically notable enophthalmos, but one immediate revisional operation was needed because of a displaced bone graft. Otherwise, the desired position of the graft was confirmed via computed tomography. The endoscopically assisted transconjunctival approach to the orbital medial wall provides improved surgical exposure of the most posterior and superior aspects of the fracture site, enabling more accurate reduction of orbital soft tissue and placement of bone grafts.  相似文献   
88.
Peripheral gamma delta T-cell deficit in nasopharyngeal carcinoma   总被引:5,自引:0,他引:5  
Previous studies identified CD56(+) and CD56(-) subsets of peripheral gamma delta T cells from healthy donors. Both subsets responded to stimulation by a myeloma cell line, XG-7 and undergo vigorous ex vivo expansion in the presence of exogenous IL-2. They are cytotoxic for different tumor targets including nasopharyngeal carcinoma, but they differ from one another in that the CD56(-) subset has an additional growth requirement for IL-7 and exhibited greater cytotoxicity against nasopharyngeal carcinoma (NPC) targets. These immune cells were further shown to retard tumor growth in a nude mice NPC model. To assess if these immune cells might contribute to host defense against NPC, we compared gamma delta T-cell status of NPC patients with healthy donors and survivors who had been in clinical remission of the cancer. It was found that peripheral gamma delta T cells of patients were impaired in their response to the stimulatory effects of XG-7 and exhibited weak or essentially no cytotoxicity for the NPC targets. The deficits were present in early and advanced stages of the cancer but were restored among survivors after successful treatment of the cancer. These findings support a role for peripheral gamma delta T cells in host defense against NPC. It was noted that these immune cells comprise less than 5% of peripheral blood monocytic cells and hence it was not surprising that this component of host defense was breached early in the development of the cancer.  相似文献   
89.
OBJECTIVE: Chronic hypertension is associated with an increased risk for tissue injury that may be mediated in part by endothelium and inflammatory cells. To clarify a possible underlying mechanisms, we examined leukocyte migration in the microcirculation and concomitant parenchymal cell death. METHODS: The mesentery of spontaneously hypertensive rats (SHRs) and their normotensive controls, Wistar Kyoto (WKY) rats, was examined with digital fluorescence microscopy after topical stimulation with an inflammatory mediator (f-met-leu-phe, 10(-8)M). The migratory pathways of individual leukocytes were traced, and at the same time cell death was detected by use of a life-death indicator (propidium iodide) over a period of 3 hours. RESULTS: Both WKY and SHR had a progressively increasing number of leukocytes migrating across the endothelium in postcapillary venules into the tissue parenchyma. But parenchymal cell death was detected in a random pattern in the mesentery tissue, without correlation to the migratory positions of the leukocytes. Although mature SHR rats (about 17 weeks) exhibited the same level of cell death as age-matched WKY rats, older WKY rats (about 30 weeks) had significantly lower levels of cell death, whereas the SHR rats maintained the same number of parenchymal cell death as mature animals. CONCLUSIONS: These results suggest that in the presence of an inflammatory mediator, the SHR may exhibit a stronger response to an inflammatory mediator than normotensive WKY rats in a fashion that is age, but not blood pressure, dependent. Parenchymal cell death does not correlate with migration of activated leukocytes at the microvascular level.  相似文献   
90.
We report a case of a 50 year old man referred to our department with a history of mild cough, dyspnea and dysphagia. The thoracic CT scan showed a large solid mass in the anterior mediastinum, corresponding to the findings in the chest radiographs.A 67Ga scintigraphy was performed and showed high pathological accumulation in the anterior mediastinum. A subsequent fine needle aspiration biopsy (FNAB) showed the presence of malignant cells, suggesting thymic carcinoma. Although this type of tumour is uncommon, it should be taken into account in order to establish the differential diagnosis of gallium-avid mediastinal masses.  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