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   3899篇
  免费   243篇
  国内免费   14篇
耳鼻咽喉   20篇
儿科学   172篇
妇产科学   28篇
基础医学   600篇
口腔科学   88篇
临床医学   253篇
内科学   1002篇
皮肤病学   205篇
神经病学   274篇
特种医学   84篇
外科学   677篇
综合类   21篇
预防医学   93篇
眼科学   48篇
药学   212篇
中国医学   16篇
肿瘤学   363篇
  2023年   28篇
  2022年   50篇
  2021年   75篇
  2020年   45篇
  2019年   68篇
  2018年   102篇
  2017年   92篇
  2016年   76篇
  2015年   96篇
  2014年   80篇
  2013年   129篇
  2012年   210篇
  2011年   230篇
  2010年   106篇
  2009年   103篇
  2008年   202篇
  2007年   218篇
  2006年   195篇
  2005年   211篇
  2004年   183篇
  2003年   154篇
  2002年   183篇
  2001年   92篇
  2000年   91篇
  1999年   81篇
  1998年   52篇
  1997年   30篇
  1996年   33篇
  1995年   40篇
  1994年   31篇
  1993年   40篇
  1992年   89篇
  1991年   82篇
  1990年   62篇
  1989年   56篇
  1988年   47篇
  1987年   55篇
  1986年   51篇
  1985年   44篇
  1984年   20篇
  1983年   23篇
  1982年   16篇
  1981年   17篇
  1980年   14篇
  1979年   35篇
  1978年   21篇
  1974年   13篇
  1969年   17篇
  1968年   14篇
  1967年   13篇
排序方式: 共有4156条查询结果,搜索用时 156 毫秒
51.
Hepatoblastoma is the most common malignant liver tumor in children. Recently, liver transplantation has been indicated for unresectable hepatoblastoma. We retrospectively reviewed 14 children with a diagnosis of hepatoblastoma who had undergone living-donor liver transplantation (LDLT) at Kyoto University Hospital. During the period from June 1990 to December 2004, 607 children underwent LDLT. Of these interventions, 2.3% were performed for hepatoblastoma. Based on radiological findings, the pre-treatment extent of disease (PRETEXT) grouping was used for pre-treatment staging of the tumor. There were grade III in seven patients and grade IV in seven patients. Thirteen patients received chemotherapy, and seven underwent hepatectomy 11 times. Immunosuppressive treatment consisted of tacrolimus monotherapy in 11 patients. Actuarial 1- and 5-year graft and patient survival rates were 78.6% and 65.5%. The poor prognostic factors were macroscopic venous invasion and extrahepatic involvement with 1-year and 5-year survival rates of 33.0% and 0%. Pediatric patients without these factors showed an acceptable 5-year survival rate of 90.9%. LDLT provides a valuable alternative with excellent results in children with hepatoblastoma because it allows optimal timing of the liver transplantation, given the absence of delay between the completion of chemotherapy and planned liver transplantation.  相似文献   
52.
Eye and head movements are coordinated during head-free pursuit. To examine whether pursuit neurons in frontal eye fields (FEF) carry gaze-pursuit commands that drive both eye-pursuit and head-pursuit, monkeys whose heads were free to rotate about a vertical axis were trained to pursue a juice feeder with their head and a target with their eyes. Initially the feeder and target moved synchronously with the same visual angle. FEF neurons responding to this gaze-pursuit were tested for eye-pursuit of target motion while the feeder was stationary and for head-pursuit while the target was stationary. The majority of pursuit neurons exhibited modulation during head-pursuit, but their preferred directions during eye-pursuit and head-pursuit were different. Although peak modulation occurred during head movements, the onset of discharge usually was not aligned with the head movement onset. The minority of neurons whose discharge onset was so aligned discharged after the head movement onset. These results do not support the idea that the head-pursuit-related modulation reflects head-pursuit commands. Furthermore, modulation similar to that during head-pursuit was obtained by passive head rotation on stationary trunk. Our results suggest that FEF pursuit neurons issue gaze or eye movement commands during gaze-pursuit and that the head-pursuit-related modulation primarily reflects reafferent signals resulting from head movements.  相似文献   
53.
OBJECT: The effects of percutaneous transluminal angioplasty (PTA) and stent placement for stenosis of the petrous or cavernous portion of the internal carotid artery (ICA) were compared. METHODS: Twenty-four patients with symptomatic, greater than 60% stenosis of the petrous or cavernous portion of the ICA were treated using PTA or stent placement; 15 were treated with PTA and nine with stent insertion. Initial and follow-up results (> 3 months posttreatment) were compared in each group. Stenotic portions of the ICA were successfully opened in 13 of 15 patients in the PTA group, and in all nine patients in the stent-treated group. In one case in the PTA group stent delivery was attempted; however, the device could not pass through the vessel's tortuous curve, and PTA alone was performed in this case. Postoperatively, the mean stenotic ratio decreased from 72.1 to 29.6% in the PTA group, and from 75.6 to 2.2% in the stent-treated group. In four patients in the PTA group, stenoses greater than 50% were demonstrated on follow-up angiography performed at 3 to 6 months after PTA. In the stent-treated group, no restenosis was encountered, although in one case acute occlusion of the stent occurred; the device was recanalized with PTA and infusion of tissue plasminogen activator. This case was the only one of the 24 in which any neurological deficits related to the endovascular procedure occurred. Stent placement brought a greater gain in diameter than did PTA at the initial and late follow-up period; this gain was statistically significant. CONCLUSIONS: Stent placement is more effective than PTA for stenosis of the petrous or cavernous portion of the ICA from the viewpoint of initial and late gain in diameter.  相似文献   
54.
Alagille syndrome (AGS) is an autosomal dominant genetic disorder characterized by chronic cholestasis, congenital heart disease, peculiar facies, butterfly-like vertebrae, and posterior embryotoxon. Liver dysfunction is the common presentation of AGS, and liver transplantation may be indicated. This study examines the outcome of living-related liver transplantation (LRLT) for AGS. Twenty patients with AGS (median age 5.0 years, range 0.6-12.9) underwent LRLT at Kyoto University Hospital between June 1990 and February 2002. Five potential donors were excluded because of paucity of intrahepatic bile ducts diagnosed by preoperative liver biopsy and one because of a hepatic vascular anomaly. The overall 5-year patient survival was 80.4%. Three patients died as the result of the following: complications related to surgery, heart failure caused by progressive pulmonary artery stenosis, and a graft with unsuspected bile duct paucity. Liver dysfunction was improved in all successful cases, and catch-up growth occurred in 90% of patients. LRLT is an efficacious treatment modality for AGS if donors are selected by cautious evaluation to rule out unsuspected bile duct paucity.  相似文献   
55.
We estimated collimator scatter factor, S(c), of symmetric rectangular fields of any size by applying a two-component scatter model to measured in-air output data in width and length directions of measured rectangles. The in-air output was measured for symmetric rectangles with combined width and length sizes of 7 x 7 and 6 x 6 using 10 MV and 4 MV X-rays of Varian's Clinac 2100 C/D, respectively. The model consists of scatter components from the primary collimator and flattening filter and from the collimator jaws: the former shows a saturation curve and the latter increases linearly with enlarging field size. This model was fitted to the measured dataset firstly in the width and secondly in the length directions of rectangles; then, by compiling interpolated matrix data, the S(c) table of symmetric rectangles was constructed. In addition, using this S(c) table, values of S(c) were calculated for a few asymmetric rectangles by Day's method, and were in good agreement with measured values. Therefore, we think that our method is practical and precise for constructing the S(c) table of symmetric rectangles from measured data, and that using this table, the S(c) of any asymmetric rectangles may be calculated.  相似文献   
56.
PURPOSE: To assess the apparent diffusion coefficient (ADC) value and diffusion tensor image (DTI) including fractional anisotropy (FA) of the noncancerous prostate and prostate cancer before and after carbon-ion radiotherapy (CIRT). MATERIALS AND METHODS: Nine patients with biopsy-proven prostate cancer underwent 1.5T magnetic resonance (MR) examinations. One patient with benign prostatic hypertrophy and one healthy volunteer were also examined as references. The changes in ADC values and DTI of the entire prostate calculated from b-values of 0 and 700 (s/mm(2)) were estimated between before and after CIRT. RESULTS: ADC values of prostate cancer significantly increased after CIRT by paired t-test (P < 0.01) but those of noncancerous inner gland (IG) and peripheral zone (PZ) showed no significant change. By analysis of variance, significant differences in ADC values were observed among prostate cancer and noncancerous IG and PZ before CIRT (P < 0.05). After CIRT, those significant differences had disappeared. FAs showed no significant differences in any comparisons. DTI showed changes in the direction of the main axis of the tensor in prostate cancer after CIRT. CONCLUSION: There were changes in ADC and DTI in prostate cancer after CIRT. They may be useful for monitoring prostatic structural changes under radiotherapy.  相似文献   
57.
Seventeen patients were given lower dose and intermittent oral administration of estramustine phosphate (6 mg/kg/day) and etoposide (30 mg/m2/day) for 7 days. Then administration was discontinued for 7 days. This administration cycle was repeated. Therapy was continued until evidence of disease progression or unacceptable toxicity occurred. Fifteen of the 17 patients were finally evaluated for PSA response. Overall, the pretreatment PSA levels were lowered at least 50% from baseline in 7 (47%) of the 15 patients. The median survival was 65 weeks. Five of the 17 patients complained of anorexia or nausea during the treatment, but none of them showed over grade 2 anorexia, none requiring transfusion or hospitalization. None of the patients showed edema, deep venous thrombosis, thrombocytopenia, anemia or myocardial infarction. Because of its rare and mild adverse effects, this intermittent administration of oral estramustine and oral etoposide may be a useful and secure regimen for hormone refractory prostate cancer.  相似文献   
58.
59.
Liver transplantation is now an established technique to treat children with end-stage liver disease. Implantation of left lateral segment grafts (Couidaud's segments II and III) can be a problem in small infants because of a large-for-size graft. Reduced left lateral segmental liver transplantation has been recently introduced for small infants to mitigate the problem of large-for-size graft. Further reduction of the left lateral segment graft increases the possibility of supplying an adequate hyperreduced left lateral segment graft as an alternative surgical technique. We report 3 cases of our experience of transplantation using hyperreduced left lateral segment grafts from living donors.  相似文献   
60.

Purpose

The aim of the study was to investigate posttraumatic stress disorder (PTSD) in mothers of children who have undergone surgery for congenital disease at a pediatric surgery department.

Methods

A questionnaire survey was carried out in 145 mothers of children who had undergone surgery and were still alive. For comparison, the mothers were categorized into 3 groups according to the severity of their child's disease.

Results

Of the 145 mothers, 29 (20%) were likely to be diagnosed as having developed PTSD at the time of the survey. Posttraumatic stress disorder symptoms correlated with factors such as anxiety and condition of the child. In terms of the disease severity of the child, factors such as anxiety tended to be observed more frequently in the higher disease severity group, whereas the proportion of mothers likely to be diagnosed as having developed PTSD was smallest in the moderate-severity group.

Conclusions

Twenty percent of the mothers of children had probably developed PTSD. In the moderate-severity group, there seemed to be a factor that alleviated PTSD symptoms. Because mothers provided effective care for the symptoms of children in the moderate-severity group, this observation suggests that participation of the mother in their child's treatment might prevent them from developing PTSD symptoms.  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