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   4296篇
  免费   316篇
  国内免费   8篇
耳鼻咽喉   57篇
儿科学   215篇
妇产科学   53篇
基础医学   485篇
口腔科学   112篇
临床医学   458篇
内科学   826篇
皮肤病学   43篇
神经病学   293篇
特种医学   457篇
外科学   710篇
综合类   71篇
一般理论   5篇
预防医学   267篇
眼科学   64篇
药学   178篇
中国医学   6篇
肿瘤学   320篇
  2021年   50篇
  2020年   32篇
  2019年   49篇
  2018年   59篇
  2017年   32篇
  2016年   49篇
  2015年   56篇
  2014年   84篇
  2013年   123篇
  2012年   138篇
  2011年   160篇
  2010年   123篇
  2009年   125篇
  2008年   153篇
  2007年   145篇
  2006年   128篇
  2005年   134篇
  2004年   134篇
  2003年   136篇
  2002年   124篇
  2001年   115篇
  2000年   137篇
  1999年   100篇
  1998年   93篇
  1997年   76篇
  1996年   92篇
  1995年   78篇
  1994年   74篇
  1993年   74篇
  1992年   107篇
  1991年   99篇
  1990年   91篇
  1989年   131篇
  1988年   119篇
  1987年   129篇
  1986年   119篇
  1985年   118篇
  1984年   69篇
  1983年   65篇
  1982年   51篇
  1981年   40篇
  1980年   44篇
  1979年   58篇
  1978年   40篇
  1977年   65篇
  1976年   44篇
  1975年   57篇
  1974年   43篇
  1973年   31篇
  1972年   35篇
排序方式: 共有4620条查询结果,搜索用时 125 毫秒
1.
2.
Capillary malformation–arteriovenous malformation syndrome (CM‐AVM) is an autosomal dominant disorder caused by RASA1 mutations. The prevalence and phenotypic spectrum are unknown. Evaluation of patients with multiple CMs is challenging because associated AVMs can be life threatening. The objective of this study was to describe the clinical characteristics of children presenting with features of CM‐AVM to an academic pediatric dermatology practice. After institutional review board approval was received, a retrospective chart review was performed of patients presenting between 2009 and 2012 with features of CM‐AVM. We report nine cases. Presenting symptoms ranged from extensive vascular stains and cardiac failure to CMs noted incidentally during routine skin examination. All demonstrated multiple CMs, two had Parkes Weber syndrome, and two had multiple infantile hemangiomas. Seven patients had family histories of multiple CMs; three had family histories of large, atypical CMs. Six had personal or family histories of AVMs. Genetic evaluation was recommended for all and was pursued by six families; four RASA1 mutations were identified, including one de novo. Consultations with neurology, cardiology, and orthopedics were recommended. Most patients (89%) have not required treatment to date. CM‐AVM is an underrecognized condition with a wide clinical spectrum that often presents in childhood. Further evaluation may be indicated in patients with multiple CMs. This study is limited by its small and retrospective nature.  相似文献   
3.
4.
Background: Pemetrexed and cisplatin have recently been shown to significantly improve survival compared with cisplatin alone. However, there are only limited data reflecting teaching hospital experience outside a clinical trial. Pemetrexed has only been available in Australia on a restricted basis since 2002. We reviewed our experience of patients treated on the Australian ‘Special Access Scheme’ at three major thoracic oncology units. Methods: Charts were reviewed for all patients enrolled on the scheme. Data was extracted on age, World Health Organization (WHO) performance status, histology, prior therapy, time from diagnosis to starting pemetrexed, chemotherapy (pemetrexed alone or with a platinum), cycle number, response rate, actuarial progression‐free and overall survival. Doses were cisplatin 75 mg/m2 or carboplatin AUC = 5 and pemetrexed 500 mg/m2 every 21 days. Results: 52 patients (32 male and 20 female) were reviewed. Median age was 58 years and 88% were WHO 0–1. Histology included 54% epithelial, 17% biphasic (epithelial and sarcomatoid) and 21% undefined. The median time from diagnosis to administration of pemetrexed was 145 days. Sixty‐five percent had minimal surgical intervention with video assisted thoracoscopy, pleurodesis and biopsy, while 19% had received prior palliative radiation. Seventy‐one percent were chemotherapy naïve, the remaining 29% having received previous platinum and/or gemcitabine regimens. Twenty‐three percent had pemetrexed alone, 35% in combination with carboplatin and 42% with cisplatin. The median number of cycles was 4 (range 1–13). The response rate was 33%. No toxicity was observed in 20% grade 3–4 toxicity in 10% (majority nausea/vomiting). The median progression‐free and overall survival times from starting pemetrexed were 184 days and 298 days, respectively. Conclusions: Pemetrexed‐based regimens are safe and effective in a community setting in malignant mesothelioma.  相似文献   
5.
Nonocclusive mesenteric ischemia (NOMI) is a disorder with an extremely high mortality. Salvage of affected patients requires early recognition and aggressive intervention to prevent intestinal gangrene. Dialysis patients represent a group at particularly high risk for this condition. Clinicians should develop a high index of suspicion for NOMI in dialysis patients to lessen the risk of death. A high interventional posture must be maintained due to the notoriously unreliable signs and symptoms of this disorder.  相似文献   
6.
Several underlying metabolic abnormalities may be present in patients with recurrent calcium calculus disease (RCCD). The aim of this study was to determine the prevalence of deficiencies of 2 well-known potent inhibitors of crystal formation and growth, citrate and pyrophosphate, in the various metabolic subgroups and as single defects. In 107 patients with RCCD, urinary citrate was significantly decreased in all metabolic subgroups with 49% of patients having hypocitraturia (2.53 +/- 1.19 mmol/24 h) versus controls (3.44 +/- 0.96 mmol/24 h; p less than 0.001). Reduced pyrophosphate:creatinine ratios were present in all the patient subgroups, and 48% of all patients had reduced ratios (1.68 +/- 1.68 vs. 3.10 +/- 2.66 in controls; p less than 0.01). There was no correlation between citrate and pyrophosphate concentration. Isolated hypocitraturia was found in 11.2%, reduced pyrophosphate:creatinine ratios as the single defect in 11.2% and a combination of both in 12.1% of patients. Thus inhibitor defects play an important role in patients with RCCD and frequently occur as isolated biochemical defects.  相似文献   
7.
We have studied long-term (to 60 days) effects of 4 degrees C storage in culture media on the histologic, mechanical, and chemical properties of the cartilage from osteochondral shell allografts from the dog. The structural integrity of the cartilage matrix was intact up to 60 days of storage, for the mechanical properties represented by the aggregate modulus and apparent permeability remained normal. These data are supported by normal safranin-O staining as well as normal glycosaminoglycan content and total collagen concentration. However, chondrocyte viability, as assessed by 35SO4 uptake and hematoxylin and eosin preparations, decreased dramatically with time. We believe that the longer storage to 60 days is not indicated, unless conditions can be modified to maintain cell viability.  相似文献   
8.
The heart in rheumatoid arthritis--a clinical and echocardiographic study   总被引:2,自引:0,他引:2  
A clinical and echocardiographic study was carried out in a randomly selected group of 101 patients with rheumatoid arthritis to determine the prevalence of cardiac abnormalities. Adequate two-dimensional assessments were obtained in 84 patients and 77 patients had adequate M mode recordings. Thirty-one patients (37 per cent) had 45 echocardiographic abnormalities. Five patients (6 per cent) had a pericardial effusion. Eleven abnormalities of the mitral valve were noted in 10 patients (13 per cent). Three patients had mitral valve prolapse, one patient with aortic incompetence had flutter on the mitral valve, five patients had mitral annular calcium and one patient had hypertrophic obstructive cardiomyopathy and mitral annular calcification. A reduction in the E-F slope was noted in 12 patients, seven of whom had associated cardiac disease, one patient had a sinus tachycardia and four patients (5 per cent) had a mild reduction without any other cardiac abnormality. Apart from the presence of pericardial effusion in 6 per cent and minor abnormalities of the E-F slope in 5 per cent of patients, all the other significant echocardiographic abnormalities could be related to the presence of associated cardiac disease.  相似文献   
9.
Xylocandin is a complex of novel peptides with potent antifungal activity that is produced by Pseudomonas cepacia ATCC 39277. The complex was isolated from the fermentation broth by extraction with butanol-methanol, 9:1, followed by collection of the precipitate formed upon concentration of the solvent extract. Purification was effected by chromatography on reversed phase and size exclusion gels followed by TLC on silica gel. These techniques afforded eight components: A1, A2, B1, B2, C1, C2, D1 and D2. A mixture of the two closely related components, xylocandins A1 and A2, displayed potent anticandidal and antidermatophytic activities in vitro. The activity was diminished by the presence of serum or vaginal washings. No antibacterial activity was demonstrable.  相似文献   
10.
It has been reported that growth hormone (GH) deficiency induced cardiomyopathy responds to growth hormone replacement therapy. We describe the case of a middle-aged male with cardiomyopathic heart failure and growth hormone deficiency of the adult secondary to surgical panhypopituitarism. We demonstrate clinical and hemodynamic improvement of cardiac function with growth hormone replacement therapy despite underlying structural heart disease.  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