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   2578篇
  免费   187篇
  国内免费   12篇
耳鼻咽喉   12篇
儿科学   61篇
妇产科学   30篇
基础医学   378篇
口腔科学   85篇
临床医学   219篇
内科学   578篇
皮肤病学   104篇
神经病学   195篇
特种医学   122篇
外科学   344篇
综合类   15篇
一般理论   3篇
预防医学   151篇
眼科学   38篇
药学   158篇
中国医学   6篇
肿瘤学   278篇
  2024年   6篇
  2023年   54篇
  2022年   95篇
  2021年   136篇
  2020年   78篇
  2019年   95篇
  2018年   115篇
  2017年   85篇
  2016年   115篇
  2015年   108篇
  2014年   125篇
  2013年   144篇
  2012年   208篇
  2011年   227篇
  2010年   117篇
  2009年   98篇
  2008年   142篇
  2007年   151篇
  2006年   102篇
  2005年   118篇
  2004年   115篇
  2003年   100篇
  2002年   84篇
  2001年   15篇
  2000年   19篇
  1999年   15篇
  1998年   8篇
  1997年   4篇
  1996年   6篇
  1995年   6篇
  1994年   6篇
  1993年   6篇
  1992年   9篇
  1991年   8篇
  1990年   5篇
  1989年   8篇
  1988年   6篇
  1987年   2篇
  1985年   4篇
  1981年   4篇
  1980年   2篇
  1978年   4篇
  1976年   3篇
  1975年   2篇
  1974年   3篇
  1972年   1篇
  1971年   5篇
  1970年   2篇
  1969年   2篇
  1966年   2篇
排序方式: 共有2777条查询结果,搜索用时 15 毫秒
21.
Photoacoustic imaging is a promising new technology that combines tissue optical characteristics with ultrasound transmission and can potentially visualize tumor depth in bladder cancer. We imaged simulated tumors in 5 fresh porcine bladders with conventional pulse‐echo sonography and photoacoustic imaging. Isoechoic biomaterials of different optical qualities were used. In all 5 of the bladder specimens, photoacoustic imaging showed injected biomaterials, containing varying degrees of pigment, better than control pulse‐echo sonography. Photoacoustic imaging may be complementary to diagnostic information obtained by cystoscopy and urine cytologic analysis and could potentially obviate the need for biopsy in some tumors before definitive treatment.  相似文献   
22.
BACKGROUND: Although membranous nephropathy is a common cause of nephrotic syndrome in adults, its treatment remains under debate. METHODS: To clarify the effects of steroid therapy, the data of 51 Japanese adult patients with idiopathic membranous nephropathy who received treatment at our department were analyzed retrospectively. We divided the patients with nephrotic syndrome and a serum creatinine level <1.7 mg/dL, into two groups: the steroid therapy group (n=20) and the non-steroid therapy group (n=7), and compared the clinical characteristics between the two groups. RESULTS: Significantly decreased proteinuria levels (p<0.05) after 2 and 5 years were observed in the steroid therapy group as compared to the non-steroid therapy group. There was no significant difference in the serum creatinine levels after 2 and 5 years between the steroid therapy group and the non-steroid therapy group. CONCLUSION: Steroid therapy in idiopathic membranous nephropathy showed good efficacy in patients with nephrotic syndrome.  相似文献   
23.
A male newborn infant born at 38 weeks of gestation and weighing 2,660 g, was diagnosed as esophageal atresia. Although there was mild cyanosis at birth, his initial ultrasonographic examination performed by neonatologist showed normal anatomy of the heart. He underwent a surgical repair of esophageal atresia under general anesthesia. Anesthesia was induced with fentanyl and pancuronium, and maintained with sevoflurane and 60% oxygen. Frequent desaturation occurred during the procedure, requiring manual hyperventilation with 100% oxygen. Since blood pressure during the operation was unstable, volume loading with albumin was attempted. Further echocardiography was performed by pediatric cardiologist after going back to NICU. This revealed total anomalous pulmonary venous connection (TAPVC). He underwent cardiac surgery for repair of TAPVC on the next day. Although TAPVC was not preoperatively diagnosed regardless of results of echocardiogram, cyanosis and unstable blood pressure should be considered as signs of potential cardiac disease. Fluid restriction, higher hemoglobin, lower inspired oxygen and slightly higher carbon dioxide rather than albumin administration and hyperventilation should have been attempted during the esophageal repair.  相似文献   
24.
Hemipelvectomy is surgery for pelvic bone neoplasms. In the case of pubic bone osteosarcoma, the distal end of the rectus abdominis muscle is severed from the pubic and ischium bones, and the pelvic floor muscles are resected en bloc with the bone, which leads to stress urinary incontinence. Cancer control is prioritized over complications, and stress urinary incontinence is generally disregarded. A 25‐year‐old woman presented with stress urinary incontinence. She had undergone a hemipelvectomy for left pubic bone osteosarcoma, and stress urinary incontinence appeared and persisted since the surgery. We carried out a reconstruction of the tissue deficit of the rectus abdominis using the tensor fascia lata muscle flap simultaneously with a midurethral autologous fascial sling anchoring to the tensor fascia lata flap. Stress incontinence was successfully improved without morbidity. This is the first reported case of midurethral suspension with reconstruction of the lower abdominal wall with the tensor fascia lata flap for post‐hemipelvectomy stress urinary incontinence.  相似文献   
25.
Living‐donor lobar lung transplantation (LDLLT) is an established therapy for patients with end‐stage lung disease, but living‐donor lobar lung retransplantation (re‐LDLLT) is rarely reported. We previously reported a case of unilateral antibody‐mediated rejection after LDLLT in the presence of newly formed donor‐specific antibodies against a right‐lobe donor. The same patient developed contralateral bronchiolitis obliterans, resulting in bilateral bronchiolitis obliterans, but re‐LDLLT was successful. Pathological findings of the explanted lungs were consistent with the clinical course of the patient. One year after re‐LDLLT, the patient is doing well without any anti‐human leukocyte antigen antibodies. Four lobes from four different donors were transplanted in this patient. The first two lobes were rejected eventually, but the two lobes implanted later presented no signs of rejection at least for 1 year after the transplant. Herein, we report this rare case and compare the clinical course and pathological findings.  相似文献   
26.
Hyaluronan in wound healing: Rediscovering a major player   总被引:1,自引:0,他引:1  
Wound healing involves a series of carefully modulated steps, from initial injury and blood clot to the final reconstituted tissue or scar. A dynamic reciprocity exists throughout between the wound, blood elements, extracellular matrix, and cells that participate in healing. Multiple cytokines and signal transduction pathways regulate these reactions. A major component throughout most of the process is hyaluronan, a straight‐chain carbohydrate extracellular matrix polymer. Hyaluronan occurs in multiple forms, chain length being the only distinguishing characteristic between them. Levels of hyaluronan in its high–molecular‐weight form are prominent in the earliest stages of wound repair. Progressively more fragmented forms occur in a manner not previously appreciated. We outline here steps in the wound healing cascade in which hyaluronan participates, as well as providing a review of its metabolism. Although described by necessity in a series of quantum steps, the healing process is constituted by a smooth continuum of overlapping reactions. The prevalence of hyaluronan in the wound (initially termed “hexosamine‐containing mucopolysaccharide”), particularly in its early stages, was pointed out over half a century ago by the Harvard surgeon J. Engelbert Dunphy. It appears we are now returning to where we started.  相似文献   
27.
OBJECTIVE: Immediate loss of thrombomodulin activity in the endothelium of vein grafts has been demonstrated during 90 min exposure to arterial circulation; this loss of activity is ascribed as an important cause of early thrombosis. Conventional ex vivo gene transfection after vein harvest cannot cover this acute period immediately after implantation. We have established a highly efficient non-viral gene therapy protocol utilizing modified transferrin receptor-facilitated gene transfer. Using this technique, we examined whether in vivo thrombomodulin gene therapy, directed to the endothelium of rat veins 2 days prior to grafting, may prevent thromboresistance impairment of vein grafts under simulated arterial circulation. METHODS: Abdomen of SD rat was opened and cationic liposome:transferrin:thrombomodulin gene complexes or the vector without DNAs were applied to the inferior vena cava of rats while blood flow was reduced by proximal and distal clamping. After 2 days, the transfected veins were harvested and thrombomodulin expression and thromboresistance properties determined before and after exposure to an artificial circuit. RESULTS: The trial of gene transfection using variable doses of DNAs confirmed that 7.5 microg of total DNAs was the most efficient quantity for thrombomodulin gene transfection to IVCs, although accompanying an increase of gene expression in other downstream organs. By transfection of the thrombomodulin gene in IVCs, the generation capacity of activated protein C in venous endothelium increased three-fold compared with veins treated with vector alone (P<0.01). Under simulated arterial circulation, perfusion of veins treated with vector alone decreased thrombomodulin activity to 36% of preperfused levels (P<0.01), whereas transfected grafts preserved the activity at normal vein endothelium levels even after perfusion. Consequently, the increase in endothelial thrombin activity induced by simulated arterial circulation was markedly attenuated in transfected veins (P<0.01), while immunohistochemistry confirmed the preservation of endothelial lining. CONCLUSIONS: Transferrin receptor-facilitated in vivo gene transfer to the inferior vena cava resulted in sufficient thrombomodulin gene expression immediately after graft implantation and subsequent maintenance of thromboresistance even after exposure to arterial pressure. Although further studies are needed, the present results suggest the possibility of gene therapy targeting acute phases of vein graft disease.  相似文献   
28.
A 70-year-old man was referred to our department for surgical treatment for aortic valve stenosis. He was diagnosed with aortic regurgitation 30 years ago, but he was asymptomatic at that time. Ten years ago, chronic hemodialysis was instituted for diabetic nephropathy. In recent years, he became aware of nocturnal dyspnea and echocardiography revealed moderate aortic stenosis. After that, the symptom was getting worse and surgical treatment was indicated. We performed aortic valve replacement. Intraoperatively, we noticed his aortic valve was quadricuspid. The postoperative course was uneventful and he was discharged without complications. Quadricuspid aortic valve is rare congenital anomaly and patients are often operated on for aortic regurgitation. Our case is indicated for valve replacement because of aortic stenosis. In addition, there are a few reports of quadricuspid aortic valve associated with hemodialysis. We consider hemodialysis is one of the cause of rapid progression of aortic stenosis in this patient.  相似文献   
29.
30.
The utility of measuring the corpus callosal angle (CA) for the diagnosis of idiopathic normal pressure hydrocephalus (INPH) was investigated. Three-dimensional magnetic resonance imaging (MRI) was performed in 34 INPH patients, 34 Alzheimer’s disease (AD) patients, and 34 normal control (NC) subjects. Measurement of the CA on the coronal MR images of the posterior commissure perpendicular to the anteroposterior commissure plane was performed for all subjects. The CA of the INPH group (mean ± SD, 66 ± 14°) was significantly smaller than those of the AD (104 ± 15°) and NC (112 ± 11°) groups. When using the threshold of the mean − 2SD value of the NC group (= 90°), an accuracy of 93%, sensitivity of 97%, and specificity of 88% were observed for discrimination of INPH from AD patients. Measuring the CA helps in differentiating INPH patients from AD and normally aged subjects.  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