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   1118篇
  免费   87篇
  国内免费   8篇
耳鼻咽喉   3篇
儿科学   58篇
妇产科学   11篇
基础医学   99篇
口腔科学   35篇
临床医学   172篇
内科学   275篇
皮肤病学   14篇
神经病学   29篇
特种医学   267篇
外科学   76篇
综合类   31篇
预防医学   33篇
眼科学   7篇
药学   41篇
中国医学   5篇
肿瘤学   57篇
  2023年   9篇
  2021年   16篇
  2020年   9篇
  2019年   11篇
  2018年   26篇
  2017年   17篇
  2016年   20篇
  2015年   23篇
  2014年   27篇
  2013年   27篇
  2012年   27篇
  2011年   21篇
  2010年   40篇
  2009年   57篇
  2008年   37篇
  2007年   15篇
  2006年   25篇
  2005年   14篇
  2004年   12篇
  2003年   23篇
  2002年   23篇
  2001年   20篇
  2000年   16篇
  1999年   17篇
  1998年   53篇
  1997年   54篇
  1996年   65篇
  1995年   48篇
  1994年   45篇
  1993年   50篇
  1992年   14篇
  1991年   7篇
  1990年   16篇
  1989年   40篇
  1988年   32篇
  1987年   37篇
  1986年   39篇
  1985年   32篇
  1984年   21篇
  1983年   9篇
  1982年   22篇
  1981年   14篇
  1980年   9篇
  1979年   3篇
  1978年   5篇
  1977年   12篇
  1976年   13篇
  1975年   15篇
  1970年   3篇
  1966年   4篇
排序方式: 共有1213条查询结果,搜索用时 15 毫秒
151.
152.
Global cancer statistics, 2012   总被引:5,自引:0,他引:5       下载免费PDF全文
Cancer constitutes an enormous burden on society in more and less economically developed countries alike. The occurrence of cancer is increasing because of the growth and aging of the population, as well as an increasing prevalence of established risk factors such as smoking, overweight, physical inactivity, and changing reproductive patterns associated with urbanization and economic development. Based on GLOBOCAN estimates, about 14.1 million new cancer cases and 8.2 million deaths occurred in 2012 worldwide. Over the years, the burden has shifted to less developed countries, which currently account for about 57% of cases and 65% of cancer deaths worldwide. Lung cancer is the leading cause of cancer death among males in both more and less developed countries, and has surpassed breast cancer as the leading cause of cancer death among females in more developed countries; breast cancer remains the leading cause of cancer death among females in less developed countries. Other leading causes of cancer death in more developed countries include colorectal cancer among males and females and prostate cancer among males. In less developed countries, liver and stomach cancer among males and cervical cancer among females are also leading causes of cancer death. Although incidence rates for all cancers combined are nearly twice as high in more developed than in less developed countries in both males and females, mortality rates are only 8% to 15% higher in more developed countries. This disparity reflects regional differences in the mix of cancers, which is affected by risk factors and detection practices, and/or the availability of treatment. Risk factors associated with the leading causes of cancer death include tobacco use (lung, colorectal, stomach, and liver cancer), overweight/obesity and physical inactivity (breast and colorectal cancer), and infection (liver, stomach, and cervical cancer). A substantial portion of cancer cases and deaths could be prevented by broadly applying effective prevention measures, such as tobacco control, vaccination, and the use of early detection tests. CA Cancer J Clin 2015;65: 87–108. © 2015 American Cancer Society.  相似文献   
153.
154.
Goblet cell carcinoid tumours are often considered a subset of appendiceal neuroendocrine tumours which behave more aggressively. They usually metastasize through transcoelomic/peritoneal invasion and common sites include the ovaries, peritoneum, and liver. Metastases may have goblet cell carcinoid, signet ring cell carcinoma or classic carcinoid histology. We report the first case in the literature of a patient with a goblet cell carcinoid with lung metastasis, which was associated with unfavourable outcome.Key Words: Appendiceal neuroendocrine tumours, Goblet cell, Carcinoid tumour  相似文献   
155.
Gellan gum (GG)‐based hydrogels are advantageous in tissue engineering not only due to their ability to retain large quantities of water and provide a similar environment to that of natural extracellular matrix (ECM), but also because they can gelify in situ in seconds. Their mechanical properties can be fine‐tuned to mimic natural tissues such as the nucleus pulposus (NP). This study produced different formulations of GG hydrogels by mixing varying amounts of methacrylated (GG‐MA) and high‐acyl gellan gums (HA‐GG) for applications as acellular and cellular NP substitutes. The hydrogels were physicochemically characterized by dynamic mechanical analysis. Degradation and swelling abilities were assessed by soaking in a phosphate buffered saline solution for up to 170 h. Results showed that as HA‐GG content increased, the modulus of the hydrogels decreased. Moreover, increases in HA‐GG content induced greater weight loss in the GG‐MA/HA‐GG formulation compared to GG‐MA hydrogel. Potential cytotoxicity of the hydrogel was assessed by culturing rabbit NP cells up to 7 days. An MTS assay was performed by seeding rabbit NP cells onto the surface of 3D hydrogel disc formulations. Viability of rabbit NP cells encapsulated within the different hydrogel formulations was also evaluated by Calcein‐AM and ATP assays. Results showed that tunable GG‐MA/HA‐GG hydrogels were non‐cytotoxic and supported viability of rabbit NP cells. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
156.
Malignant uveal melanoma and simulating lesions: MR imaging evaluation   总被引:7,自引:0,他引:7  
Twenty-one patients with intraocular disease were studied by magnetic resonance (MR) imaging and computed tomography (CT). In 13 cases, malignant uveal melanoma was considered the likely diagnosis. Both imaging methods were accurate in determining the location and size of uveal melanomas. MR imaging was superior for the assessment of possible associated retinal detachment, for assessment of vitreous change, and for differentiating uveal melanoma from choroidal hemangioma and choroidal detachment. A case of retinal gliosis could not be differentiated from uveal melanoma by either technique. Uveal melanomas appeared as hyperintense lesions on T1-weighted images and as hypointense lesions on T2-weighted images. High signal intensity of the vitreous was observed in patients with vitritis and in those who were thought to have protein leaking into the vitreous as a result of impairment of the retinal-blood barrier.  相似文献   
157.
Bile duct stones: percutaneous transhepatic removal   总被引:3,自引:0,他引:3  
Clouse  ME; Stokes  KR; Lee  RG; Falchuk  KR 《Radiology》1986,160(2):525-529
Percutaneous transhepatic intervention for transduodenal removal of biliary stones was performed 38 times in 34 patients with obstructive jaundice, biliary colic, and cholangitis. The technique entailed the percutaneous transhepatic placement of a modified Dormia basket in the common duct with the flexible tip in the duodenum. The stones were passed into the duodenum and were crushed, or were crushed in the common duct and passed as fragments into the duodenum. In addition to the snare procedure, monooctanoin was used 18 times to dissolve remaining fragments of stone and sludge that could not be snared and passed into the duodenum. The average time for completion of the procedure was 10 days. There were no deaths from the procedure. The complication rate was 21%--probably no greater than would occur with surgery in a similar patient population. The procedure can be performed when endoscopic retrograde cholangiopancreatography and sphincterotomy with stone removal is technically impossible or refused, and in patients who have previously undergone choledochojejunostomy.  相似文献   
158.
159.
160.
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