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   1679篇
  免费   93篇
  国内免费   21篇
耳鼻咽喉   14篇
儿科学   25篇
妇产科学   30篇
基础医学   214篇
口腔科学   57篇
临床医学   132篇
内科学   469篇
皮肤病学   33篇
神经病学   109篇
特种医学   36篇
外科学   276篇
综合类   4篇
预防医学   35篇
眼科学   6篇
药学   125篇
肿瘤学   228篇
  2024年   4篇
  2023年   27篇
  2022年   33篇
  2021年   87篇
  2020年   40篇
  2019年   63篇
  2018年   70篇
  2017年   35篇
  2016年   54篇
  2015年   53篇
  2014年   49篇
  2013年   61篇
  2012年   103篇
  2011年   122篇
  2010年   57篇
  2009年   37篇
  2008年   93篇
  2007年   109篇
  2006年   70篇
  2005年   85篇
  2004年   60篇
  2003年   67篇
  2002年   68篇
  2001年   33篇
  2000年   32篇
  1999年   26篇
  1998年   20篇
  1997年   8篇
  1996年   16篇
  1995年   13篇
  1994年   9篇
  1993年   5篇
  1992年   18篇
  1991年   14篇
  1990年   23篇
  1989年   9篇
  1988年   11篇
  1987年   12篇
  1986年   9篇
  1985年   9篇
  1984年   6篇
  1983年   6篇
  1981年   7篇
  1980年   7篇
  1979年   7篇
  1978年   7篇
  1977年   8篇
  1972年   4篇
  1969年   5篇
  1966年   4篇
排序方式: 共有1793条查询结果,搜索用时 15 毫秒
991.
992.
993.
Optical topography is a method for visualization of conical activity. Ways of improving the spatial resolution of the topographical image with three arrangements of optical fibres are discussed. A distribution of sensitivity is obtained from the phantom experiment, and used to reconstruct topographical images of an activation area of the brain with the fibres in each arrangement. The correlations between the activated area and the corresponding topographical images are obtained, and the effective arrangement of the optical fibres for improved resolution is discussed.  相似文献   
994.
Retinoids are known to be required for vertebrate reproduction, and in the male, for the maintenance of normal testicular structure and function. Previously several novel retinoic acid responsive genes, collectively designated as the Stra genes, had been isolated in the mouse. The Stra8 gene encodes a cytoplasmic protein and is expressed specific to the developing male gonad during mouse embryogenesis. In adult mouse, its expression is restricted to the premeiotic germ cells. Thus it has been suggested that the mouse Stra8 protein may play a role in the premeiotic phase of spermatogenesis.Recently a lot of genes that are expressed only in male germ cells have been isolated in the mouse. The mouse Stra8, Rnh2, Piwil2, Tex17, and Tuba7 were identified as testis-specific expressed genes. In addition, the Figla was known to be a testis- and ovary-specific gene. Recently we had reported the isolation of the human RNH2 cDNA and its expression, which is limited to the human testis. In the present study, we have isolated full-length cDNA of STRA8 and partial cDNAs of PIWIL2, FIGLA, TEX17, and TUBA7, and analyzed their expression patterns in human tissues.  相似文献   
995.
An aggressive approach to peritoneal dissemination involves peritonectomy procedures combined with preoperative intraperitoneal chemotherapy, intraoperative chemo-hyperthermia, and postoperative systemic chemotherapy. We have been performing multimodal therapy consisting of peritonectomy plus perioperative chemotherapy for the treatment of patients with peritoneal dissemination. Fifty-seven patients with established peritoneal dissemination from gastric cancer (n = 32), colon cancer (n = 17), ovarian cancer (n = 7), and mesothelioma (n = 1) have been treated with peritonectomy and intraoperative chemo-hyperthermia. Five-year survival rates of patients with gastric and colon cancer were 18% and 38%, respectively. Among various clinical factors, complete tumor resection was the most significant prognostic factor, and the prognosis of patients who underwent complete cytoreduction was significantly better than those who received incomplete cytoreduction. A multimodal therapy consisting of perioperative chemotherapy and peritonectomy with complete cytoreduction may be the most powerful method to treat patients with established peritoneal dissemination.  相似文献   
996.
997.
BACKGROUND: The age of patients with hepatocellular carcinoma (HCC) has been increasing worldwide. The objective of this study was to assess the efficacy and safety of percutaneous ethanol injection therapy (PEIT) in elderly patients with HCC. METHODS: The authors retrospectively analyzed 653 patients who were treated with PEIT between 1985 and 1997. One hundred thirty-seven patients were age > or = 70 years, 90 of 137 patients (66%) were male, and 106 of 137 patients (77%) were positive for hepatitis C virus antibodies. Both survival rates and standardized mortality ratios (SMRs) related to the causes of death were compared between patients age > or = 70 years and patients age < 70 years. RESULTS: With the exception of greater maximum tumor size in elderly patients age > or = 70 years, the clinical features of tumors and underlying liver disease were similar to those of patients age < 70 years The survival rates after PEIT in patients age > or = 70 years were 83%, 52%, and 27% at 1 year, 3 years, and 5 years, respectively. These results were comparable to the rates for patients age < 70 years (1 year, 90%; 3 years, 65%; and 5 years, 40%). In addition, there was no difference in mortality from extrahepatic disease between the two groups (9.8% for patients age > or = 70 years vs. 9.4% for patients age < 70 years; P > 0.999). The SMR of patients age > or = 70 years who died of causes related to extrahepatic disease (SMR, 0.56; 95% confidence interval [95%CI], 0.18-1.30) was lower compared with the SMR of patients age < 70 years (SMR, 1.75; 95%CI, 1.07-2.71). The SMR of patients age > or = 70 years who died of causes related to liver disease (SMR, 115; 95%CI, 84.1-153.0) was similar to that of patients age < 70 years (SMR, 120; 95%CI, 103.0-138.0). CONCLUSIONS: These results provide support for the treatment of patients with HCC age > or = 70 years by tumor ablation using PEIT.  相似文献   
998.
The efficacy of radioimmunotherapy (RIT) was evaluated by using a mouse model of testicular tumor with macro- and micrometastases to various organs. RIT consisting of a single intravenous injection of 5.8 MBq of I-131-labeled anti-placental alkaline phosphatase (PLAP) MAb was conducted one day or 7 days after testicular implantation in SCID mice of HeLa Hep2 cells expressing PLAP. RIT antitumor effect was significant for primary tumors as well as micrometastases defined by polymerase chain reaction (PCR) assay. However, ablation of tumor cells could be achieved with this treatment only at the initial stage of tumor growth in the testis, when metastasis could also be prevented. Once micrometastasis had occurred, however, complete elimination of tumor cell(s) was difficult. These findings appear to have implications for the use of RIT in treatment for micrometastasis, especially when detectable only by PCR assay.  相似文献   
999.
1000.
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