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   37654篇
  免费   3810篇
  国内免费   1591篇
耳鼻咽喉   356篇
儿科学   681篇
妇产科学   591篇
基础医学   3566篇
口腔科学   765篇
临床医学   4665篇
内科学   5450篇
皮肤病学   578篇
神经病学   2150篇
特种医学   1097篇
外国民族医学   2篇
外科学   3584篇
综合类   5727篇
现状与发展   17篇
一般理论   25篇
预防医学   3720篇
眼科学   1000篇
药学   4199篇
  54篇
中国医学   2446篇
肿瘤学   2382篇
  2024年   169篇
  2023年   527篇
  2022年   1433篇
  2021年   1860篇
  2020年   1521篇
  2019年   1202篇
  2018年   1360篇
  2017年   1358篇
  2016年   1213篇
  2015年   1646篇
  2014年   1969篇
  2013年   2127篇
  2012年   3200篇
  2011年   3294篇
  2010年   2369篇
  2009年   2020篇
  2008年   2523篇
  2007年   2345篇
  2006年   2071篇
  2005年   1885篇
  2004年   1402篇
  2003年   1300篇
  2002年   1067篇
  2001年   416篇
  2000年   359篇
  1999年   248篇
  1998年   263篇
  1997年   202篇
  1996年   147篇
  1995年   129篇
  1994年   131篇
  1993年   93篇
  1992年   110篇
  1991年   108篇
  1990年   93篇
  1989年   63篇
  1988年   62篇
  1987年   59篇
  1986年   68篇
  1985年   59篇
  1984年   64篇
  1983年   70篇
  1982年   80篇
  1981年   50篇
  1980年   42篇
  1979年   26篇
  1978年   33篇
  1977年   34篇
  1974年   19篇
  1973年   16篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
米利酮是非洋地黄,非儿茶酚胺类强心药,具有明显的正性肌力和扩血管作用。国外用于治疗难治性心衰及洋地黄中毒的心衰病人。本文用豚鼠乳头肌及主动脉条进行实验,结果表明合成与进口米利酮的正性肌力作用效价相同,对抗去甲肾上腺素缩血管的作用也等同。  相似文献   
52.
Background: Percutaneous closed needle biopsy of musculoskeletal neoplasms has gained in popularity. However, it remains controversial whether or not to resect the needle tract for fear of a local recurrence. A single published case report exists, noting the lone tract recurrence of an extremity skeletal osteosarcoma. Methods: We report on three additional individuals who demonstrated that tract local recurrences may occur after a closed needle biopsy for nonosteosarcoma, nonextremity sarcomas. For perspective, the world literature is reviewed to identify tract recurrences for other malignancies and the results of needle biopsy in musculoskeletal neoplasms. Results: Eighty-nine percent of needle tract local recurrences occur when carcinomas are subjected to biopsy, as reported in the literature. Forty-seven cases since 1950 are described representing essentially all tumor types. The nature of musculoskeletal neoplasms makes closed biopsy more difficult than for softer, more homogeneous, and easier to access neoplasms. Conclusions: Local recurrences of sarcoma may occur in closed needle biopsy tracts. Strong consideration should be given to open biopsy and tract resection.  相似文献   
53.
A case of an unusual lesion from the maxilla is presented. Macroscopically, the lesion was solid and histologically consisted of 'multiple separate keratocysts' of varying size that infiltrated into the surrounding bone and soft tissues. Panoramic image and CT scans showed a multilocular honeycomb ill-defined radiolucency with infiltration into the maxillary sinus and floor of orbit. This lesion should be differentiated from similar odontogenic lesions, such as keratoameloblastoma and papilliferous keratoameloblastoma. As there was no evidence of follicles, islands of ameloblastoma, or papilliferous structures in the entire specimen, the lesion could not be diagnosed as either a keratoameloblastoma or a papilliferous keratoameloblastoma. The invasive and destructive growth behavior, the histopathological features, and the histochemical pattern of the collagen stroma imply that this solid lesion is a neoplasia. It is suggested that the proper term for this lesion is solid variant of odontogenic keratocyst.  相似文献   
54.
甲状腺病变患者血清Leptin的浓度变化   总被引:1,自引:0,他引:1  
目的探讨甲状腺病变患者血清瘦素(leptin)浓度的变化及意义.方法本文用放射免疫分析(RIA)方法测定了114例甲状腺病变患者血清Leptin和总睾酮(TT)的浓度.结果统计学处理结果显示各病变组男性与正常对照组男性间,Leptin和TT的浓度差异均有显著性意义.结论血清Leptin的浓度变化可作为了解甲状腺病变患者营养状况的辅助指标.  相似文献   
55.
朱丹  马芳  陈燕华 《护理研究》2007,21(22):2048-2050
[目的]对中美护理本科《护理学基础》课程设置情况进行比较,为中国护理本科《护理学基础》课程改革提供可借鉴的科学依据。[方法]选取美国和中国各20所全日制护理院校对其护理专业本科课程《护理学基础》的开设情况进行统计分析。[结果]美国护理本科有65.00%的院校开设《护理学基础》,其实践学时和理论学时数分别为30学时~135学时和20学时~56学时,两者比值为1.00~3.00;中国护理本科院校均开设《护理学基础》,其实践学时和理论学时数分别为18学时~268学时和54学时~128学时,两者比值为0.33~2.31。[结论]中美护理本科《护理学基础》课程开设情况存在一定差异,我国《护理学基础》有内容较简单、操作多、理论少、学时数较多特点;而美国《护理学基础》学时数较少,实践学时所占比例较大。  相似文献   
56.
In summary, we have described two patients with CRMO and psoriasis, and have reviewed the musculoskeletal manifestations associated with pustular eruptions of the palms and soles. In view of the frequent occurrence of PPP in patients with CRMO, we suggest that the occurrence of psoriasis in our two patients is more than coincidence, and that noninfectious, inflammatory lesions of bone may be another musculoskeletal manifestation of psoriasis. This rare association, as well as the association of PPP with disorders associated with new bone formation, may shed new insights on the relatively common finding of periosteal elevation associated with psoriatic arthritis and the occasional severe juxta-articular osteolytic destructive bone lesions seen in psoriatic arthritis.  相似文献   
57.
BACKGROUND: A change in neural responsiveness may occur as the result of allergic inflammation in the lower airways as well as in the upper airways. In the lower airways, capsaicin cough sensitivity is known to reflect sensory neural reactivity. OBJECTIVE: The aim of this study was to establish whether allergic inflammation changes airway neural sensory reactivity during prolonged allergen exposure. METHODS: Ten nonsmoking patients with birch pollen-allergic asthma performed a capsaicin inhalation challenge twice, once in the off-pollen season and once during the pollen season. The number of coughs and symptoms induced by capsaicin were recorded and compared with those of healthy control subjects. RESULTS: The response to capsaicin, expressed as number of coughs, increased in a dose-dependent manner during both tests. Before the season, the response was similar to that of healthy control subjects, but during the pollen season, the reactivity was significantly increased. Variations in forced expiratory volume in 1 second were not significant before and after each challenge, and values did not change during the pollen season as compared with the winter season. CONCLUSIONS: Sensory reactivity in allergic asthmatic patients may be increased during prolonged allergen exposure as during the pollen season. This finding suggests that allergic inflammation in the lower and/or upper airways may trigger neurogenic mechanisms of significant clinical importance.  相似文献   
58.
Repetitive nerve stimulation (RNS) is a simple and rapid method for evaluation of neuromuscular transmission defects. Although the effect of exercise in conjunction with RNS is well recognized, it has not been standardized in actual patient and control groups. In a prospective study over a period of 1 year, the authors evaluated the effect of exercise in conjunction with RNS in comparison with conventional 3-Hz RNS at rest in the clinical setting. Fifty-four patients who were referred for possible neuromuscular transmission disorders, in addition to 35 healthy control subjects, were studied. Amplitude and area decremental responses with RNS at rest and after 20 seconds of maximal exercise at 1-minute intervals up to 3 minutes were evaluated. The use of RNS with exercise resulted in additional diagnostic yield of up to 36.4% compared with conventional 3-Hz RNS at rest. The standardized use of exercise with RNS is advocated for increasing its diagnostic yield in the neurophysiologic laboratory.  相似文献   
59.
隐性脊柱裂排尿功能异常的临床特征   总被引:5,自引:0,他引:5  
目的:研究伴有排尿功能障碍的隐性脊柱裂患者临床特征。方法:总结41例有明显排尿功能障碍的隐性脊柱裂患者临床资料。以18岁为界,将患者分为儿童组和成人组,所有患者均接受X线检查,除4例儿童外,均接受普通尿流动力学检查。结果:儿童组发病高峰年龄在1~2岁,主要临床表现为持续性原发性遗尿,部分伴有尿频、尿急及轻度急迫性尿失禁现象;成人组发病高峰年龄在18~26岁,主要临床表现为尿频、尿急、排尿前踌躇、排尿困难、遗尿等。结论:隐性脊柱裂患者常有排尿功能异常表现,出现症状的高峰时间为出生后及青春发育期后。X线、CT、MRI和尿流动力学等检查在隐性脊柱裂排尿功能障碍的诊断和治疗方案制定中有重要地位。  相似文献   
60.
邓凯雄  张丹 《中国美容医学》2006,15(10):1185-1186,I0007,I0008
目的:了解经固定矫治的正畸患者在牙齿美白治疗后牙齿表面中部出现较规则斑块的成因。方法:分别对正畸及非正畸治疗患者、正畸治疗前后拔除的离体牙进行牙齿美白治疗,对牙列组进行视觉对比,对离体牙组进行扫描电镜对比。结果:经正畸治疗的牙列在美白治疗后牙面有色斑存在,而正畸治疗后拔除的离体牙的扫描电镜结果则显示有釉质-树脂突嵌合层存在。结论:经正畸治疗后牙齿表层的釉质-树脂突嵌合层是导致牙面出现色斑的原因。  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