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   384788篇
  免费   24486篇
  国内免费   2843篇
耳鼻咽喉   5273篇
儿科学   8314篇
妇产科学   10109篇
基础医学   53904篇
口腔科学   11888篇
临床医学   30565篇
内科学   79470篇
皮肤病学   8676篇
神经病学   27545篇
特种医学   14233篇
外国民族医学   83篇
外科学   61525篇
综合类   9984篇
现状与发展   1篇
一般理论   65篇
预防医学   17547篇
眼科学   9725篇
药学   31378篇
  1篇
中国医学   2216篇
肿瘤学   29615篇
  2021年   2739篇
  2019年   2830篇
  2018年   4671篇
  2017年   3539篇
  2016年   3652篇
  2015年   4157篇
  2014年   5885篇
  2013年   7572篇
  2012年   10310篇
  2011年   10522篇
  2010年   6371篇
  2009年   6001篇
  2008年   9744篇
  2007年   10572篇
  2006年   10502篇
  2005年   9525篇
  2004年   9089篇
  2003年   8782篇
  2002年   8479篇
  2001年   28373篇
  2000年   28914篇
  1999年   23775篇
  1998年   5230篇
  1997年   4301篇
  1996年   3880篇
  1995年   3520篇
  1994年   3156篇
  1993年   2879篇
  1992年   16140篇
  1991年   14901篇
  1990年   14245篇
  1989年   14044篇
  1988年   12672篇
  1987年   12114篇
  1986年   11156篇
  1985年   10390篇
  1984年   6959篇
  1983年   5636篇
  1982年   2736篇
  1979年   5517篇
  1978年   3385篇
  1977年   2987篇
  1975年   2667篇
  1974年   3085篇
  1973年   2880篇
  1972年   2846篇
  1971年   2801篇
  1970年   2527篇
  1969年   2561篇
  1968年   2270篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
Bilateral cervical lymph node dissection was performed in 71 cases of papillary thyroid carcinoma, considered to be relatively early cases because of mobility, irrespective of the size of tumor or presence of node enlargement. Of these, 33 cases received additional node dissection of the anterosuperior mediastinum through longitudinal sternotomy. The number of lymph nodes examined per subject averaged 89.9, the number of metastatic nodes was 13.8, and metastasis was noted in 88.7% of all cases. Lymph node metastasis tended to be more frequent on the affected side, but was simultaneously scattered over the whole cervical area. As to sites, metastasis of paratracheal nodes on the affected side occurred at a frequency of 66.2%, inferior and superior jugular nodes at 62.0% and 59.0% respectively, pretracheal nodes at 50.7%, and tracheoesophageal nodes at 47.9%. The high incidence of para- and pretracheal nodes suggests that the lymph flow in this direction is of great importance in metastasis. In fact, lymph nodes in the mediastinum, which were directly continuous with these nodes, showed as high as 39.4% metastasis in cases of anterosuperior mediastinal extirpation. This extensive node dissection is considered to be very preferable as at least the agony of survival with carcinoma can be lessened.  相似文献   
123.
124.
125.
Liver histopathology in clinical Reye syndrome   总被引:1,自引:0,他引:1  
Analysis of the liver histopathology in 19 children with clinical Reye syndrome (RS) revealed that nine had diffuse panlobular steatosis, one giant cell hepatitis, one a mild choledochal cyst with inflammation, two multifocal spotty necrosis and one multiple centrilobular necrosis, the other five being normal. Four of the nine patients with diffuse panlobular steatosis showed microvesicular fatty droplets with central nuclei, which was consistent with findings characteristic for typical RS. Two cases showed a periportal area dominant macrovesicular fatty change, which was highly suggestive for metabolic disorder. In the other three cases, the findings were so variable in terms of the size of lipid droplets and the location of nuclei in hepatocytes that it was not possible to provide any clue for defining a diagnosis. These results confirmed the legitimacy of the diagnostic criteria of RS which included a liver biopsy as one of the mandatory conditions. They also indicated that RS-mimicking clinical pictures can be presented by miscellaneous conditions in which liver histology does not necessarily helpful in establishing definite diagnosis.  相似文献   
126.
Our experience with full-length ureteric splintage is reviewed with a note on the technique and its outcome. It is safe, effective and simple, easy to teach and easy to learn. It is recommended as the operation of choice in bilharzial ureteropathy.  相似文献   
127.
128.
Delta hepatitis virus infection in China   总被引:1,自引:0,他引:1  
To assess the prevalence, epidemiological features and prognostic implications of hepatitis D (Delta) in Sichuan Province, The People's Republic of China, 649 sera (515 from HBsAg positive patients and 134 from HBsAg negative subjects) were tested by radioimmunoassay (RIA) for antibody to the hepatitis D virus (anti-HD). Forty-seven sera (7.2%) showed some degree of reactivity. Serial dilutions of these sera indicated that prozoning was not responsible for the equivocal results. Thirty-four of the 47 sera were submitted under code to a second laboratory for independent analysis. According to those results anti-HD antibodies were detected in four of these sera. The overall prevalence of anti-HD in the HBsAg positive patients therefore was 0.8% (4/515). On the basis of clinical, biochemical and histological data 427 HBsAg positive sera were further divided into acute Type B hepatitis, chronic Type B hepatitis, healthy carrier state and hepatocellular carcinoma (HCC) subgroups. Two of 65 (3.1%) anti-HD positive sera belonged to the acute Type B hepatitis group; one of 104 (0.9%), the chronic Type B hepatitis group and one of 246 (0.4%), the healthy carrier group. No antibody was detected in sera from 12 HBsAg positive HCC patients. All HBsAg negative patients were negative for anti-HD antibody. The results of this study indicate that despite a high prevalence of hepatitis B virus infection, positive serology for delta virus is uncommon in Sichuan Province, The People's Republic of China.  相似文献   
129.
Radiation-induced meningioma. 3 cases   总被引:1,自引:0,他引:1  
During the same year (1984), we have seen 3 cases of meningiomas following radiation therapy of the brain for previously diagnosed tumors. A causal relationship between irradiation and meningioma has been postulated. Nevertheless, the coincidental occurrence in same patient of two different histological lesions is possible. The neoplasms developed after irradiation are of mesenchymal origin; they are fibrosarcomas, osteogenic sarcomas and meningiomas.  相似文献   
130.
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