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   1272167篇
  免费   95304篇
  国内免费   1614篇
耳鼻咽喉   16425篇
儿科学   41227篇
妇产科学   35120篇
基础医学   190505篇
口腔科学   35172篇
临床医学   118421篇
内科学   249684篇
皮肤病学   27459篇
神经病学   102476篇
特种医学   46928篇
外国民族医学   265篇
外科学   179824篇
综合类   25796篇
现状与发展   4篇
一般理论   574篇
预防医学   105475篇
眼科学   28175篇
药学   93125篇
  7篇
中国医学   2058篇
肿瘤学   70365篇
  2018年   13829篇
  2017年   10591篇
  2016年   11554篇
  2015年   13330篇
  2014年   18305篇
  2013年   27834篇
  2012年   38100篇
  2011年   40541篇
  2010年   23373篇
  2009年   22537篇
  2008年   38195篇
  2007年   40871篇
  2006年   40440篇
  2005年   39476篇
  2004年   37923篇
  2003年   36272篇
  2002年   35182篇
  2001年   56205篇
  2000年   57271篇
  1999年   48263篇
  1998年   13454篇
  1997年   12262篇
  1996年   12669篇
  1995年   11951篇
  1994年   11152篇
  1993年   10427篇
  1992年   38275篇
  1991年   37766篇
  1990年   36527篇
  1989年   35340篇
  1988年   32748篇
  1987年   32082篇
  1986年   30577篇
  1985年   28850篇
  1984年   21983篇
  1983年   19221篇
  1982年   11383篇
  1981年   10344篇
  1979年   20981篇
  1978年   15432篇
  1977年   12803篇
  1976年   11864篇
  1975年   12841篇
  1974年   15623篇
  1973年   15393篇
  1972年   14528篇
  1971年   13570篇
  1970年   12802篇
  1969年   12074篇
  1968年   11243篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Although malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma of adult life, it is fairly rare in the head and neck region (3-6%). Between 1983 and 1991 8 patients with MFH in the head and neck region have been observed and treated at the ENT-department of the University of Tübingen. 5 patients have been operated (laryngopharyngeal localization), 2 patients underwent irradiation (unresectable fast growing T4-tumors of the pharynx and thyroid) and one female patient refused further therapy after two resections elsewhere. Operated patients showed no evidence of disease 2-8 years after resection (all margins have been controlled histologically). Both irradiated patients died 4 respectively 2 months after full (70 Gy) and incomplete (17 Gy) radiotherapy without visible positive effects. Both patients developed pulmonary metastasis. Since MFH can grow in thin layers along musculaoponeurotic structures the exact size is not always demonstrable by ultrasound, CT or MR scans. Metastasis occur in up to 40%, preferentially in regionary lymph nodes, in lung, liver and skeletal system. These phenomenon requires a full pretherapeutic staging. Histologically MFH is sometimes hard to distinguish from other tumors as for example various sarcomas and pleomorphic carcinoma. Therefore, immunohistochemical (mesenchymal markers) and electron microscopical investigations are advised. Resection with exact histological controll of all margins is the therapy of choice. We experienced that laryngeal MFH (n = 3) can be resected without laryngectomy under certain circumstances. Although unsuccessfull in our two cases, according to the literature, radiotherapy should be administered in unresectable cases. Depending on localization and size of MFH long survival, in single cases healing, of this disease is possible by surgical treatment.  相似文献   
73.
Of 431 patients with gastric cancer observed in our institution, 23 (5.3%) had early gastric cancer (EGC). Macroscopic presentation, histology, depth of invasion, and lymph node involvement were evaluated in all the cases. All patients underwent surgery and an intensive follow-up was performed. Five of the 23 patients progressed, and the risk factors were examined. Histology seemed to be the main prognostic factor in our study, since intestinal type of EGC was associated to a significantly better prognosis. Total gastrectomy is indicated in the proximal localization of EGC, and should perhaps be performed also in cases presenting undifferentiated histology.  相似文献   
74.
Premalignant lesions of the penis include cutaneous horn, balanitis xerotica obliterans, and leukoplakia. The true incidence of progression of each of these to squamous-cell carcinoma is unknown. Bowenoid papulosis, erythroplasia of Queyrat, and Bowen's disease are histologically identical to in situ carcinoma. Although the first is consistently benign, the latter two regularly evolve into invasive cancer. Malignant scrotal lesions include squamous-cell carcinoma, liposarcoma, leiomyosarcoma, basal-cell carcinoma, extramammary Paget's disease, erythroplasia of Queyrat, malignant melanoma, and metastases. Hemangioma can be confused with carcinoma.  相似文献   
75.
76.
77.
Three hundred and twenty samples of subgingival plaque were obtained from 80 caucasian girls, ranging from 10 to 13 years of age. The samples were analyzed to verify the influence of age upon colonization of the gingival sulcus by microorganisms potentially pathogenic to the periodontal tissues. The gingival and plaque status were evaluated through the gingival index (GI) and plaque index (PlI) and the microflora was assessed by the enzymatic method benzoyl-arginine-naphthylamide (BANA). The results of the BANA test were positive for 62.50% of the tested individuals and 40% of the examined sites. The influence of age was statistically significant on BANA reactivity, and the number of positive sites was greater at 11 (57.5%) than at 12 years (28.8%).  相似文献   
78.
79.
We tested the urine of 30 infants 6 weeks to 7 months of age after they received standard 10-micrograms (0.5-ml) doses of HbOC (HibTITER) Haemophilus influenzae b (Hib) conjugate vaccine for the presence of Hib antigenuria using a commercially available latex particle agglutination assay (Directigen). Urines were collected within 1 hour, from 1 to 3 hours, at 24 hours and at 3, 6 and 9 days after vaccine administration and reactions were quantitated from 0 to 3+. In contrast to previous studies in older children which showed little or no antigenuria following HbOC vaccination, our study shows that in infants intense Hib antigenuria is evident within 2 to 3 hours and persists 3 days after vaccine administration and that less intense antigenuria may be detected in some infants for several days. With efficacious vaccines now being used in 2- to 6-month-old infants, invasive Hib disease may soon be limited to infants of this age just before their seroconversion. It should be recognized that antigenuria occurs for several days after vaccination with Hib conjugate vaccines and that it could be erroneously interpreted as evidence of invasive Hib infection.  相似文献   
80.
We describe a familial case of Marfan's syndrome with associated intrathoracic stomach detected during the neonatal period. The patient developed a primitive leukemia at 3 months of age. Acute leukemia in a patient with Marfan's syndrome has not previously been reported.  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