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   4056篇
  免费   304篇
  国内免费   18篇
耳鼻咽喉   31篇
儿科学   125篇
妇产科学   80篇
基础医学   515篇
口腔科学   81篇
临床医学   313篇
内科学   990篇
皮肤病学   288篇
神经病学   256篇
特种医学   128篇
外科学   646篇
综合类   8篇
一般理论   1篇
预防医学   289篇
眼科学   67篇
药学   319篇
中国医学   15篇
肿瘤学   226篇
  2023年   24篇
  2022年   42篇
  2021年   127篇
  2020年   71篇
  2019年   142篇
  2018年   126篇
  2017年   101篇
  2016年   98篇
  2015年   106篇
  2014年   146篇
  2013年   177篇
  2012年   286篇
  2011年   275篇
  2010年   142篇
  2009年   137篇
  2008年   256篇
  2007年   197篇
  2006年   241篇
  2005年   227篇
  2004年   212篇
  2003年   178篇
  2002年   202篇
  2001年   140篇
  2000年   133篇
  1999年   114篇
  1998年   34篇
  1997年   40篇
  1996年   18篇
  1995年   25篇
  1994年   23篇
  1993年   29篇
  1992年   40篇
  1991年   38篇
  1990年   33篇
  1989年   35篇
  1988年   23篇
  1987年   25篇
  1986年   18篇
  1985年   15篇
  1984年   9篇
  1983年   6篇
  1982年   9篇
  1981年   4篇
  1980年   4篇
  1979年   4篇
  1978年   4篇
  1977年   7篇
  1976年   5篇
  1975年   5篇
  1971年   4篇
排序方式: 共有4378条查询结果,搜索用时 15 毫秒
991.
992.
Congenital erythropoietic porphyria (CEP), or Günther's disease, is an inborn error of metabolism produced by a deficiency of uroporphyrinogen III synthase (UROS), the fourth enzyme of the heme biosynthesis pathway. This enzymatic defect induces the accumulation of isomer I porphyrins in erythrocytes, skin, and tissues, producing various clinical manifestations. Severe cases are characterized by extreme photosensitivity, causing scarring and mutilations, and by hemolytic anemia, reducing life expectancy. CEP is caused by mutations in the UROS gene, and one of the most severe forms of the disease is associated with a cysteine to arginine substitution at residue 73 of the protein (C73R). CEP has been successfully treated only by the transplantation of hematopoietic precursors. We report the case of a male infant with severe postdelivery symptoms diagnosed with CEP and found to be homozygous for the C73R mutation. He underwent successful allogeneic bone marrow transplantation from a matched unrelated donor at 7 months of age. The hemolytic anemia was corrected and the porphyrin overproduction was significantly reduced. The patient remained asymptomatic after 1 year. This new case confirms that patients with severe CEP can benefit from early postnatal hematopoietic stem cell transplantation.  相似文献   
993.
ObjectiveTo assess the outcome of hand-assisted laparoscopic nephrectomy in patients with significant complicating clinical factors.MethodsA retrospective assessment was made of 100 laparoscopic nephrectomies performed at a single hospital from 2001 to 2005. Patients with a history of prior abdominal surgery, prior procedures on the involved kidney, evidence of perirenal inflammation, renal lesions 10 cm or more in diameter, or level I renal vein thrombosis were enrolled.ResultsTwelve patients were enrolled. Of these, 5 had a lesion at least 10 cm in diameter, 2 had renal vein thrombosis, and 5 reported major abdominal surgery. Most patients had more than one of these findings. Three patients showed inflammatory conditions (staghorn calculi) and a T4 renal tumor was successfully treated without conversion to open surgery. Mean operating time and blood loss were 210 minutes and 310 ml respectively, while mean length of hospital stay was 3 days. No patient required conversion to open surgery.ConclusionsHand-assisted laparoscopic nephrectomy is an attractive minimally invasive option for technically challenging tumors and has reasonable operating times, blood losses, and complication rates.  相似文献   
994.
995.
996.
Sebaceous carcinoma has a predominant periocular origin but can also be extraocular. These two groups have distinct clinical courses. Insight into the molecular determinants of tumorigenesis and metastasis is limited. There is no effective treatment for metastatic sebaceous carcinoma. Epidermal growth factor receptor (EGFR) is implicated in tumorigenesis and can be a therapeutic target in certain settings. We evaluated EGFR levels by immunohistochemistry (IHC), comparing its expression between periocular and extraocular tumors and assessed EGFR mutation status. IHC was performed in 36 cases: 19 periocular and 17 extraocular (10 associated with Muir‐Torre syndrome—MTS). EGFR IHC was scored for percentage of positive cells (< 5%, 5–25%, 26–50%, > 50%) and intensity (+1 = low , +2 = moderate , +3 = high ). Extraocular carcinomas showed markedly increased levels of EGFR when compared to periocular carcinoma cases, both in terms of distribution (88% were > 25% of tumor cells vs. 16%) and intensity (77% were 2+ or 3+ vs. 21%) (p < 0.001). Among extraocular cases, there was significantly lower EGFR expression in MTS‐related cases (p < 0.05). No EGFR mutations were identified. Our results underscore the divergent mechanisms underlying the tumorigenesis of periocular and extraocular sebaceous carcinoma and suggest an association between aggressive behavior and increased EGFR expression in extraocular sebaceous carcinoma. Ivan D, Prieto VG, Esmaeli B, Wistuba II, Tang X, Lazar AJF. Epidermal growth factor receptor (EGFR) expression in periocular and extraocular sebaceous carcinomas.  相似文献   
997.
One important goal of cancer immunotherapy is to prevent and treat tumor metastasis. We have previously reported the significant antitumor effect induced by the immunization with our human papillomavirus therapeutic protein-based vaccine (LALF32-51-E7) without adjuvant and admixed with clinically relevant adjuvants in the subcutaneous TC-1 tumor challenge model. In the present study, we evaluated the efficacy of the above mentioned vaccine formulations in controlling the hematogenous spread of TC-1 tumor cells using a more tumourigenic clone named TC-1* and other intravenous injection site less stressful than the tail vein. We generated a lung metastasis model by injecting TC-1* cells into the retro-orbital venous sinus and this is the first study describing it. Also, this is the first study that demonstrates the efficacy of the immunization with LALF32-51-E7 without adjuvant and admixed with VSSP or Al(OH)3 in controlling metastatic tumors increasing the survival of the mice. Our TC-1 lung metastasis model can be used to test the efficacy of other immunotherapeutic strategies based on E6/E7 antigens.  相似文献   
998.
Wireless capsule endoscopy (CE) is a technology developed for the endoscopic exploration of the small bowel. The first capsule model was approved by the Food and Drug Administration in 2001, and its first and essential indication was occult gastrointestinal (GI) bleeding. Over subsequent years, this technology has been refined to provide superior resolution, increased battery life, and capabilities to view different parts of the GI tract. Indeed, cases for which CE proved useful have increased significantly over the last few years, with new indications for the small bowel and technical improvements that have expanded its use to other parts of the GI tract, including the esophagus and colon. The main challenges in the development of CE are new devices with the ability to provide therapy, air inflation for a better vision of the small bowel, biopsy sampling systems attached to the capsule and the possibility to guide and move the capsule with an external motion control. In this article we review the current and new indications of CE, and the evolving technological changes shaping this technology, which has a promising potential in the coming future of gastroenterology.  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