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   3129篇
  免费   209篇
  国内免费   29篇
耳鼻咽喉   104篇
儿科学   122篇
妇产科学   40篇
基础医学   363篇
口腔科学   73篇
临床医学   346篇
内科学   691篇
皮肤病学   41篇
神经病学   289篇
特种医学   223篇
外科学   406篇
综合类   42篇
预防医学   247篇
眼科学   58篇
药学   150篇
中国医学   11篇
肿瘤学   161篇
  2023年   16篇
  2022年   34篇
  2021年   49篇
  2020年   31篇
  2019年   59篇
  2018年   83篇
  2017年   70篇
  2016年   60篇
  2015年   60篇
  2014年   93篇
  2013年   123篇
  2012年   141篇
  2011年   159篇
  2010年   104篇
  2009年   112篇
  2008年   141篇
  2007年   142篇
  2006年   137篇
  2005年   129篇
  2004年   90篇
  2003年   120篇
  2002年   103篇
  2001年   109篇
  2000年   110篇
  1999年   97篇
  1998年   66篇
  1997年   61篇
  1996年   66篇
  1995年   60篇
  1994年   37篇
  1993年   36篇
  1992年   44篇
  1991年   48篇
  1990年   36篇
  1989年   54篇
  1988年   50篇
  1987年   53篇
  1986年   46篇
  1985年   37篇
  1984年   28篇
  1983年   24篇
  1982年   30篇
  1981年   21篇
  1980年   24篇
  1979年   16篇
  1978年   17篇
  1977年   22篇
  1976年   24篇
  1974年   12篇
  1973年   11篇
排序方式: 共有3367条查询结果,搜索用时 15 毫秒
1.
2.
3.
Coronary artery bypass grafts: visualization with MR imaging   总被引:1,自引:0,他引:1  
Gomes  AS; Lois  JF; Drinkwater  DC  Jr; Corday  SR 《Radiology》1987,162(1):175
  相似文献   
4.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.  相似文献   
5.
BACKGROUND: Merkel cell carcinoma is a rare malignant neuroendocrine neoplasm characteristically arising from the dermis of sunlight-exposed skin. It rarely arises outside the skin. OBJECTIVE: We present a patient with primary Merkel cell carcinoma arising from subcutaneous fat, with no involvement of the overlying skin. We describe the clinical manifestations and magnetic resonance imaging (MRI) findings. METHODS: We report a 63-year-old woman with a primary lesion of Merkel cell carcinoma that arose from the subcutaneous fat layer of the left arm. The lesion presented as a subcutaneous nodule with intact overlying skin. MRI showed that the nodular lesion was located entirely in the subcutaneous fat layer, with no involvement of the dermis. Peritumoral infiltration around the lesion and enlarged lymph nodes deep to the lesion were noted. The patient received wide excision of the lesion with dissection of the regional lymph nodes and adjuvant radiotherapy and chemotherapy. RESULTS: Histopathologic examination confirmed the diagnosis of Merkel cell carcinoma with local lymphatic metastasis, and the lesion was completely located in the subcutaneous fat, with no involvement of the dermis. These findings were well correlated with MRI findings. CONCLUSION: Primary Merkel cell carcinoma may arise from the subcutaneous fat and present as an entirely subcutaneous lesion with intact skin. MRI is helpful to evaluate the local extension of the lesion and regional lymphatic metastasis.  相似文献   
6.
7.
表小檗碱对α受体的作用   总被引:2,自引:0,他引:2  
王嘉陵  方达超 《药学学报》1990,25(4):289-292
表小檗碱(epiberberine,EB)是从湖北产黄连(Coptis chinensis Franch)中提取的一种生物碱,属苯喹嗪类原小檗碱,对其药理作用的研究资料甚少,未见其对α肾上腺素体作用的报道。资料表明,许多原小檗碱类化合物有α受体阻滞作用,为从该类化合物中选择  相似文献   
8.
Orthotopic liver transplantation was performed in 20 pigs. Serum total bile acids (STBA) were determined and their profile compared with standard early function parameters: total bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactic acid. In phase I, the STBA level was 32.89 +/- 1.29 mumol/l. In phase II, STBA accumulated to 84.46 +/- 15.25 mumol/l (p less than 0.01), followed by hepatic clearance in phase III (63.61 +/- 9.71 mumol/1; NS). Between phase III and 6- and 12-hour samples, STBA decreased progressively, reaching values of 33.63 +/- 7.05 mumol/l at 24 h. AST was elevated in phases I, II, III, and at 6, 12 and 24 h (p less than 0.001), as was ALT (but with insignificant differences). Thus, STBA and their profile appear to be earlier and more specific indicators of early graft function than conventional parameters.  相似文献   
9.
The purpose of this pilot study was to observe both relaxed and deep breathing patterns in a convenience sample to determine the incidence of normal versus faulty patterns of respiration. These observations were then combined with respondent answers to a survey on pain history to determine if there is any correlation between faulty breathing and musculo-skeletal pain patterns. If such a correlation can be made, then we propose that clinicians working with chronic pain patients may have improved outcomes if they address and correct faulty breathing patterns. Based on this study, it is suggested to include the evaluation and treatment of faulty respiration in the rehabilitation of chronic musculo-skeletal conditions, most notably cervical pain.  相似文献   
10.
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