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   8986篇
  免费   436篇
  国内免费   69篇
耳鼻咽喉   85篇
儿科学   364篇
妇产科学   467篇
基础医学   1329篇
口腔科学   190篇
临床医学   797篇
内科学   1506篇
皮肤病学   420篇
神经病学   606篇
特种医学   588篇
外科学   1185篇
综合类   268篇
一般理论   4篇
预防医学   389篇
眼科学   189篇
药学   476篇
  2篇
中国医学   32篇
肿瘤学   594篇
  2022年   74篇
  2021年   129篇
  2020年   89篇
  2019年   93篇
  2018年   107篇
  2017年   92篇
  2016年   108篇
  2015年   133篇
  2014年   190篇
  2013年   277篇
  2012年   348篇
  2011年   389篇
  2010年   293篇
  2009年   292篇
  2008年   363篇
  2007年   369篇
  2006年   403篇
  2005年   385篇
  2004年   391篇
  2003年   353篇
  2002年   347篇
  2001年   195篇
  2000年   182篇
  1999年   174篇
  1998年   166篇
  1997年   126篇
  1996年   117篇
  1995年   115篇
  1994年   81篇
  1993年   93篇
  1992年   78篇
  1991年   89篇
  1990年   72篇
  1989年   87篇
  1988年   110篇
  1987年   110篇
  1986年   86篇
  1985年   104篇
  1984年   72篇
  1983年   61篇
  1981年   43篇
  1979年   60篇
  1977年   43篇
  1976年   41篇
  1975年   43篇
  1956年   39篇
  1955年   52篇
  1954年   44篇
  1928年   46篇
  1913年   43篇
排序方式: 共有9491条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
The use of vacuum assisted closure (V.A.C.) therapy in postoperative infections after dorsal spinal surgery was studied retrospectively. Successful treatment was defined as a stable healed wound that showed no signs of acute or chronic infection. The treatment of the infected back wounds consisted of repeated debridement, irrigation and open wound treatment with temporary closure by V.A.C. The instrumentation was exchanged or removed if necessary. Fifteen patients with deep subfascial infections after posterior spinal surgery were treated. The implants were exchanged in seven cases, removed completely in five cases and left without changing in one case. In two cases spinal surgery consisted of laminectomy without instrumentation. In two cases only the wound defects were closed by muscle flap, the remaining ones were closed by delayed suturing. Antibiotic treatment was necessary in all cases. Follow up was possible in 14 patients. One patient showed a new infection after treatment. The study illustrates the usefulness of V.A.C. therapy as a new alternative management for wound conditioning of complex back wounds after deep subfascial infection.  相似文献   
5.
Background Beating heart surgery has now become the commonest technique of doing Coronary Artery Bypass Graft Surgery (CABG) in our country. It is being used even in such high risk situations like diffuse coronary disease and Critical Left Main stem Stenosis (LMCS) with good results. The aim of this study is to retrospectively review our results in Off-Pump Coronary Artery Bypass Surgery (OPCAB) in patients with critical left main stem stenosis. Methods This study is a retrospective analysis of the data of patients who underwent primary coronary artery bypass surgery. During the period from April 2003 to September 2005 a total of 64 patients underwent OPCAB procedure for critical LMCS. During the same period 10 patients underwent CABG on Cardio Pulmonary Bypass (CPB). The age range was 36–77yrs. The sex distribution was M: F 53∶10. Ten patients were done as emergency. 2 of them were on Intra Aortic Balloon Pump (IABP) support preoperatively. 10 patients were high risk with a Euro score of ≥5. Results Left Internal Mammary Artery (LIMA) was used in 78% of cases. Average grafts per patient was 2.96. The median ventilation time was 5.91 hrs. New IABP insertion in postoperative period was required in 1 patient. One patient was reexplored for bleeding. There was one perioperative myocardial infarction. 57% of patients did not need any blood transfusion. There was no conversion to CPB. There was no operative mortality. Inotropes were used in ten cases. Conclusions OPCAB is a safe method of revascularization in patients with critical LMCS. Preoperative IABP is useful in patients with cardiogenic shock. However, there is a place for CPB in patients needing additional procedures like Mitral Valve repair (MV repair) or Dor's procedure or when the vessels are very diffusely diseased. Those patients who are unstable despite IABP support may be managed by Beating heart On Pump (BHOP) technique.  相似文献   
6.
7.
8.
The disintegrin and metalloproteinase 10 (ADAM10) is a membrane‐anchored metalloproteinase with both proteolytic and disintegrin characteristics. Here, we investigate the expression, regulation, and functional role of ADAM10 in axonal outgrowth and myelination of the peripheral nerve. Expression pattern analysis of 11 ADAM family members in co‐cultures of rat dorsal root ganglia (DRG) neurons and Schwann cells (SCs) demonstrated the most pronounced mRNA expression for ADAM10. In further studies, ADAM10 was found to be consistently upregulated in DRG‐SC co‐cultures before the induction of myelination. Neurons as well as SCs widely expressed ADAM10 at the protein level. In neurons, the expression of ADAM10 was exclusively limited to the axons before the induction of myelination. Inhibition of ADAM10 activity by the hydroxamate‐based inhibitors GI254023X and GW280264X resulted in a significant decrease in the mean axonal length. These data suggest that ADAM10 represents a prerequisite for myelination, although its activity is not required during the process of myelination itself as demonstrated by expression analysis of myelin protein zero (P0) and Sudan black staining. Hence, during the process of myelin formation, ADAM10 is highly upregulated and appears to be critically involved in axonal outgrowth that is a requirement for myelination in the peripheral nerve. © 2009 Wiley‐Liss, Inc.  相似文献   
9.
Growth of malignant tumors is dependent on sufficient blood supply. Thus, inhibition of tumor angiogenesis is emerging as a promising target in the treatment of malignancies. Human angiostatin (hANG) is one of the most potent inhibitors of endothelial cell proliferation, angiogenesis, and tumor growth in vivo. However, its mechanisms operating in vivo are not well understood. METHODS: To obtain more information about functional changes in the angiogenic process, we established Morris hepatoma (MH3924A) cell lines expressing hANG (hANG-MH3924A). The effects of hANG expression on proliferation and apoptosis of human umbilical vein endothelial cells (HUVECs) were measured in coculture experiments in vitro. To evaluate changes in tumor perfusion and blood volume, H2 15O and 68Ga-DOTA-albumin (DOTA is 1,4,7,10-tetraazacyclododecane-N,N',N',N'-tetraacetic acid) were used for PET studies in vivo. Additionally, immunohistologic quantification of vascularization, apoptosis, and proliferation as well as gene array analyses were performed. RESULTS: Our in vitro experiments demonstrate reduced proliferation and increased apoptosis in HUVECs when being cocultured with hANG-MH3924A. In support, tumor growth of hANG-MH3924A is diminished by 95% in vivo. However, tumor perfusion and blood volume are increased in hANG-MH3924A corresponding to an increased microvessel density. Furthermore, hANG-transfected tumors show changes in expression of genes related to apoptosis, stress, signal transduction, and metabolism. CONCLUSION: hANG expression leads to inhibition of tumor growth, increased apoptosis, and changes in the expression of multiple genes involved in stress reactions, signal transduction, and apoptosis, which indicates a multifactorial reaction of tumors. An enhanced microvessel density is seen as part of these reactions and is associated with increased perfusion as measured by PET.  相似文献   
10.
About 3–4% of all tumors and tumor-like lesions of the skeleton are located in the foot. Many of these lesions have a predilection for certain locations, so that the spectrum of entities occurring in the foot differs from the rest of the skeleton. Despite the fact that practically any entity can occur in the foot in rare cases, taken together the ten most frequent lesions make up for the vast majority of tumors and tumor-like lesions of the foot. The differential diagnosis of these lesions follows the general principles that apply in the rest of the skeleton. It is based on the analysis of the lesion’s X-ray morphology and location, the patient’s age, and in certain entities, the MR morphology. This article describes the most important tumors and tumor-like lesions of the foot, their differential diagnosis, and the principles of local staging.  相似文献   
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