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   6942篇
  免费   350篇
  国内免费   45篇
耳鼻咽喉   67篇
儿科学   70篇
妇产科学   70篇
基础医学   758篇
口腔科学   215篇
临床医学   416篇
内科学   1911篇
皮肤病学   74篇
神经病学   512篇
特种医学   416篇
外科学   1422篇
综合类   40篇
预防医学   179篇
眼科学   182篇
药学   338篇
中国医学   5篇
肿瘤学   662篇
  2023年   48篇
  2022年   100篇
  2021年   166篇
  2020年   84篇
  2019年   123篇
  2018年   155篇
  2017年   119篇
  2016年   113篇
  2015年   148篇
  2014年   171篇
  2013年   223篇
  2012年   400篇
  2011年   396篇
  2010年   236篇
  2009年   226篇
  2008年   363篇
  2007年   349篇
  2006年   339篇
  2005年   384篇
  2004年   319篇
  2003年   335篇
  2002年   315篇
  2001年   165篇
  2000年   165篇
  1999年   182篇
  1998年   75篇
  1997年   42篇
  1996年   61篇
  1995年   50篇
  1994年   50篇
  1993年   49篇
  1992年   119篇
  1991年   121篇
  1990年   122篇
  1989年   111篇
  1988年   107篇
  1987年   121篇
  1986年   102篇
  1985年   106篇
  1984年   47篇
  1983年   45篇
  1982年   28篇
  1981年   24篇
  1979年   46篇
  1978年   26篇
  1977年   41篇
  1974年   24篇
  1971年   19篇
  1970年   19篇
  1969年   20篇
排序方式: 共有7337条查询结果,搜索用时 12 毫秒
101.
A 52-year-old Japanese female was admitted to our hospital for microhematuria, proteinuria and progressive renal dysfunction. Two years prior to admission, she was diagnosed with lung adenocarcinoma and multiple bone and brain metastases, and was treated with gefitinib (250 mg/day). Treatment for 6 months induced partial response with 30% regression of the primary lung tumor, and resolution of metastatic tumors. After confirmation of the partial remission state, we performed percutaneous renal biopsy. Glomeruli showed mild to moderate mesangial proliferation, segmental endocapillary proliferation and occasional fibrocellular crescent formation. In addition, severe interstitial fibrosis and tubular atrophy relative to the degree of glomerular sclerosis were noted. Immunofluorescence microscopy showed predominant IgA deposition in the mesangial area. Electron microscopy revealed subepithelial and paramesangial electron-dense deposits. In consideration of the prognosis of lung cancer and complication of immunosuppressive treatment, we continued gefitinib only and closely followed-up the clinical course in the outpatient clinic. Sixteen months later, she continued to have proteinuria and microhematuria, and the severity of renal dysfunction was still the same. However, the lung cancer started to increase in size. This is quite an unusual case presenting histologically with tubulointerstitial nephritis and IgA nephropathy in a patient on long-term treatment with gefitinib.  相似文献   
102.
A 42-year-old woman was admitted to Kyushu University hospital because of 6 months' history of bilateral leg edema. Upon admission, ascites and pleural effusion as well as systemic edema were noted. Laboratory tests revealed hypoalbuminemia of 1.5 g/dl and massive proteinuria of 10 g/day. She was diagnosed with nephrotic syndrome. Renal biopsy revealed diffuse thickening of the glomerular basement membrane (GBM) and a crescent-like extracapillary lesion with segmental sclerosis in four of 11 glomeruli. Immunoglobulins and complements were negative by immunofluorescence examination. Therefore, we diagnosed this as focal segmental glomerulosclerosis (FSGS) rather than membranous nephropathy. Using an electron microscope, we observed a thickening of the GBM with numerous intramembranous vesicle-like microstructures and an infolding of the podocyte into the GBM. Since the microstructures were partly demarcated by a unit membrane and some of them were located very closely to the infolded podocyte, we speculated that the microstructures were derived from the podocyte. The unique electron microscopic finding of our case is a disease entity rather than a reactive phenomenon.  相似文献   
103.
Nagase K  Iida H  Dohi S 《Anesthesia and analgesia》2002,94(4):954-8, table of contents
Although it has been reported that ketamine attenuates hypercapnia-induced cerebral vasodilation, the mechanism remains unknown. Because nitric oxide is involved in cerebral CO2 reactivity, we studied the effects of L-arginine and nitroglycerin on ketamine-mediated attenuation of vascular responses to hypercapnia. Under pentobarbital anesthesia, 16 rabbits underwent closed cranial window preparation. Hypercapnic challenges were repeated after IV saline, ketamine (10 mg/kg, followed by 20 mg x kg(-1) x h(-1)), or ketamine plus either L-arginine (150 mg/kg, followed by 100 mg x kg(-1) x h(-1); n = 8) or nitroglycerin (5 microg x kg(-1) x min(-1) infusion; n = 8). Ketamine reduced hypercapnia-induced cerebral vasodilation (1.27%/mm Hg +/- 0.45%/mm Hg [saline] versus 0.82%/mm Hg +/- 0.53%/mm Hg [ketamine]: P < 0.05), but L-arginine restored reactivity (1.28%/mm Hg +/- 0.73%/mm Hg: P < 0.05 versus ketamine), as did nitroglycerin (1.14%/mm Hg +/- 0.73%/mm Hg [saline] versus 0.56%/mm Hg +/- 0.63%/mm Hg [ketamine]: P < 0.05, and 1.15%/mm Hg +/- 0.74%/mm Hg [ketamine plus nitroglycerin]: P < 0.05 versus ketamine). This indicates that ketamine attenuates cerebral CO2 reactivity, at least in part, via suppression of nitric oxide-cyclic guanosine monophosphate mechanisms in the cerebral vasculature. IMPLICATIONS: The attenuation of cerebral vasodilation to hypercapnia seen under ketamine anesthesia is reversed by L-arginine or nitroglycerin infusion.  相似文献   
104.
We studied 13 consecutive patients with bone and soft tissue sarcomas of the hand and wrist. Chondrosarcoma, Ewing's sarcoma, synovial sarcoma and epithelioid sarcoma were the most frequent histological diagnoses. Limb-sparing surgery was performed in ten patients but eventually three patients required an amputation. Surgical margins were wide in nine patients and marginal in four. Adjuvant therapy for nine patients consisted of chemotherapy in five and chemotherapy with radiation in four. Local recurrence occurred in two patients with epithelioid sarcoma. There was no significant relationship between surgical margin and local recurrence. Distant metastasis occurred in four patients. The 5-year survival rate was 66%. The mean functional score was 87%. Our study indicates that treatment consisting of resection of these tumours with either a wide margin or a marginal margin followed by adjuvant radiation appeared to be safe and resulted in an acceptable degree of limb function except in the patients with epithelioid sarcoma.  相似文献   
105.
We report a case of bilateral internal carotid artery (ICA) stenosis treated with stenting. A 78-year-old man suffered from vascular dementia and left hemiparesis, and, by magnetic resonance angiogram (MRA), was diagnosed as having bilateral ICA stenosis. Cerebral angiogram showed severe, bilateral ICA stenosis (right; 88%, left; 93%) and xenon single photon emission tomography (SPECT) showed severely decreased cerebral blood flow (CBF) and cerebrovascular reactivity (CVR). We performed bilateral carotid angioplasty with self-expanding stents. Both CBF and CVR were improved bilaterally after the operation. The patient was discharged without neurological deficits. Carotid stenting may be an alternative treatment for severe ischemia caused by severe, bilateral ICA stenosis.  相似文献   
106.
PURPOSE: To clarify the appropriate concentration and dose of hypertonic saline solution (HSS) for preventing delayed neuronal death in the hippocampal CA1 subfield after transient forebrain ischemia in gerbils. METHODS: Thirty gerbils were randomly assigned to five groups: physiological saline solution (PSS) group, ischemia/reperfusion treated with PSS 2 mL x kg(-1); 5% HSS group, treated with 5% HSS 2 mL x kg(-1); 7.5% HSS group, treated with 7.5% HSS 2 mL x kg(-1); 10% HSS group, treated with 10% HSS 2 mL x kg(-1); 20% HSS group, treated with 20% HSS 2 mL x kg(-1). Transient forebrain ischemia was induced by occluding the bilateral common carotid arteries for four minutes. Five days later, histopathological changes in the hippocampal area were examined, and the degenerative ratio of the pyramidal cells were measured according to the following formula: (number of degenerative pyramidal cells/total number of pyramidal cells per 1 mm of hippocampal CA1 subfield) x 100. RESULTS: In PSS and 20% groups, neuronal cell damage was observed five days after ischemia. In the other three groups, these changes were not observed. The degenerative ratios of pyramidal cells were as follows; PSS group: 91.6 +/- 5.6%, 5% HSS group: 7.2 +/- 1.6%, 7.5% group: 8.3 +/- 1.4%, 10% HSS group: 6.2 +/- 1.1%, 20% HSS group: 85.8 +/- 8.7% (P < 0.05; PSS and 20% HSS vs three other groups). CONCLUSION: This study demonstrates that 5, 7.5 or 10% HSS 2 mL x kg(-1) may prevent delayed neuronal death in the hippocampal CA1 subfield after cerebral ischemia/reperfusion in gerbils.  相似文献   
107.
The authors report on a 51-year-old woman with a 9-year history of rheumatoid arthritis (RA) who presented with symptomatic rheumatoid nodules in the lumbar extradural region with compression on the L-5 nerve roots bilaterally. She had also suffered from dysesthesia in the right lower leg and intermittent claudication. Magnetic resonance imaging revealed masses compressing the dural sac, and on lumbar myelography and computed tomography myelography a filling defect at L4-5 was revealed, which was compressing the dural sac posterolaterally on both sides. The masses were surgically removed. On histological examination the typical characteristics of rheumatoid nodules were found. Soon after the operation all of the patient's symptoms disappeared. There have been few reports on extradural rheumatoid nodules. Patients with RA usually complain of articular symptoms, and in fact the patient in the present study had been referred to the authors' institution for total hip arthroplasty. However, various symptoms other than those arising from articular lesions were found clinically. The authors believe that if patients with RA are also examined for extraarticular lesions, it is likely that these will be more frequently detected.  相似文献   
108.
Background Many studies have shown that angiogenesis plays an important role in the process of cancer development and progression. Vascular endothelial growth factor (VEGF) has a potent angiogenic activity, and cyclooxygenase-2 (COX-2) supports angiogenesis by regulated production of angiogenic factors, including VEGF. The purpose of this study was to examine the expression of VEGF in combination with COX-2 and CD34, their correlation with various clinicopathological factors, and their prognostic significance in human gastric carcinoma. Methods Specimens from 169 patients with different grade and stage gastric carcinoma were investigated by immunohistochemistry for COX-2 and VEGF expression. Tumor microvessel density was assessed with CD34 immunostaining. Correlations between the expression of VEGF, COX-2, CD34, and various clinicopathological factors were studied. The effect of these proteins on patient survival was determined. Results COX-2 and VEGF were positively expressed in 36.7% and 50.3% of the patients, respectively. Positive correlation was found between VEGF and COX-2 and between VEGF and CD34. VEGF expression was correlated with depth of invasion; metastatic lymph nodes; lymphatic and venous invasion; and tumor, node, metastasis system stage. Patients with positive staining for VEGF showed far lower disease-free (64.9% vs. 81.3%) and overall (58.3% vs. 76.9%) survival rates than VEGF-negative patients. In multivariate analysis, only tumor location, depth of invasion, and lymph node metastasis were shown to be independent prognostic factors. Conclusions VEGF expression correlates with angiogenesis and tumor progression and is a valuable prognostic factor in patients with gastric carcinoma.  相似文献   
109.
Calciphylaxis (calcific uremic arteriolopathy) is a poorly understood and highly morbid syndrome of both vascular calcification and skin necrosis. The main histopathological finding is calcium deposits within arteriolar and small vessel walls, showing endovascular fibrosis associated with fat necrosis. The therapeutic strategy is to normalize the high calcium-phosphate products (Ca x P). When calciphylaxis is complicated with advanced renal hyperparathyroidism (HPT), parathyroidectomy (PTX) should be performed promptly. However, for patients with low PTH level, calciphylaxis is unresponsive to PTX, and such an approach may worsen hyperphosphatemia and hypercalcemia. We report two patients with calciphylaxis confirmed by skin biopsy. PTX was performed in both patients based on high PTH levels. PTH and Ca x P level decreased in both patients post PTX. In Case 1, the skin ulcers gradually improved and almost disappeared after PTX. However, in Case 2, new ulcers appeared after PTX. In Case 1, alkaline phosphatase (ALP) after PTX was approximately twice its level before surgery and PTX resulted in normalization of uptake on bone scintigraphy. However, no rise in ALP was noted in Case 2, probably due to long-term use of aluminum, which prevented bone formation. These findings suggest that differences in the extent of bone formation explain the different response in post-PTX ulcer healing.  相似文献   
110.
BACKGROUND: Myeloablative cord blood transplantation (CBT) for adult patients offers a 90% chance of engraftment with a 50% rate of transplant-related mortality, mostly attributable to infection. We have demonstrated the feasibility of reduced-intensity CBT (RI-CBT) for adult patients, in which cyclosporine was used for acute graft-versus-host disease (GVHD) prophylaxis. Transplantation-related mortality (TRM) was 27% within 100 days. Therefore our objective was to evaluate the feasibility of RI-CBT with tacrolimus as GVHD prophylaxis for adult patients with hematologic malignancies. METHODS: Thirty-four patients with a median age of 56.5 years (range; 22-68) with hematologic diseases underwent RI-CBT at Toranomon Hospital between November 2003 and September 2004. Preparative regimen comprised fludarabine 25 mg/m2 on days -7 to -3, melphalan 80 mg/m2 on day -2, and 4 Gy total body irradiation on day -1. GVHD prophylaxis was continuous intravenous infusion of tacrolimus 0.03 mg/kg, starting on day -1. RESULTS: Thirty-one patients achieved neutrophil engraftment at a median of day 20. Median infused total cell dose was 2.4 x 10E7/kg (range; 1.6-4.8). Thirty-two patients achieved complete donor chimerism at day 60. Grade II-IV acute GVHD occurred in 45% of patients, with a median onset of day 26. Primary disease recurred in five patients, and TRM within 100 days was 12%. Estimated 1-year overall survival was 70%. CONCLUSION: This study demonstrated the possible improvement in transplant-related mortality by tacrolimus as GVHD prophylaxis in adult RI-CBT recipients.  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