全文获取类型
收费全文 | 2888篇 |
免费 | 135篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 491篇 |
妇产科学 | 56篇 |
基础医学 | 278篇 |
口腔科学 | 35篇 |
临床医学 | 176篇 |
内科学 | 551篇 |
皮肤病学 | 81篇 |
神经病学 | 129篇 |
特种医学 | 73篇 |
外科学 | 464篇 |
综合类 | 59篇 |
预防医学 | 117篇 |
眼科学 | 84篇 |
药学 | 152篇 |
中国医学 | 6篇 |
肿瘤学 | 252篇 |
出版年
2023年 | 22篇 |
2022年 | 28篇 |
2021年 | 60篇 |
2020年 | 35篇 |
2019年 | 59篇 |
2018年 | 90篇 |
2017年 | 46篇 |
2016年 | 85篇 |
2015年 | 61篇 |
2014年 | 102篇 |
2013年 | 131篇 |
2012年 | 208篇 |
2011年 | 197篇 |
2010年 | 141篇 |
2009年 | 82篇 |
2008年 | 154篇 |
2007年 | 138篇 |
2006年 | 129篇 |
2005年 | 120篇 |
2004年 | 98篇 |
2003年 | 113篇 |
2002年 | 100篇 |
2001年 | 82篇 |
2000年 | 78篇 |
1999年 | 64篇 |
1998年 | 29篇 |
1997年 | 16篇 |
1996年 | 19篇 |
1995年 | 16篇 |
1994年 | 21篇 |
1993年 | 9篇 |
1992年 | 48篇 |
1991年 | 51篇 |
1990年 | 32篇 |
1989年 | 29篇 |
1988年 | 26篇 |
1987年 | 28篇 |
1986年 | 28篇 |
1985年 | 30篇 |
1984年 | 19篇 |
1983年 | 13篇 |
1981年 | 21篇 |
1979年 | 15篇 |
1978年 | 16篇 |
1977年 | 25篇 |
1976年 | 26篇 |
1975年 | 10篇 |
1974年 | 11篇 |
1973年 | 8篇 |
1968年 | 8篇 |
排序方式: 共有3032条查询结果,搜索用时 0 毫秒
81.
82.
A patient with multiple malformations poses a diagnostic dilemma to the pediatrician. There are thousands of malformation
syndromes described and diagnosis of a syndrome appears a daunting task. An approach to diagnosis of a malformation syndrome
is presented. Relevant details in the history and examination, important investigations, the process of differential diagnosis,
and search engines used to aid in diagnosis of a malformation syndrome are described 相似文献
83.
Neonatal Lupus Erythematosus (NLE) is an uncommon condition manifesting with congenital complete heart block and occasionally other manifestations like hepatitis. Neonatal Lupus with severe cholestasis with positive anti SS-A/Ro and anti SS-B/La antinuclear antibodies in the mother and child is being reported. 相似文献
84.
An 11-year-old girl with an almond lodging in the tracheobronchial tree is described. She presented with an uncommon symptom of subcutaneous emphysema The x-ray revealed left-sided pneumothorax and pneumomediastinum. Intercostal drain was inserted, but she developed respiratory failure and was ventilated. After initial stabilization for 60 hours, she deteriorated again and her x-ray revealed right-sided collapse. After removal of the foreign body, she was discharged but presented again with stridor necessitating tracheostomy. Tracheal stenosis was found and required end-to-end anastomosis. The authors feel that, while foreign bodies are uncommon in this age group with emphysema as a rarer manifestation, this cause should be kept in mind, even in the absence of forthcoming history. A high index of suspicion for tracheobronchial foreign body is required in atypical presentations of acute pediatric respiratory distress. 相似文献
85.
Dave U Taylor-Robinson SD Walker MM Mahon M Puri BK Thursz MR DeSouza NM Cox IJ 《European journal of gastroenterology & hepatology》2004,16(11):1199-1205
OBJECTIVES: In vitro proton magnetic resonance spectroscopy (MRS) allows changes in cell membrane lipid structure associated with dysplasia and malignant transformation to be investigated. Magic angle spinning (MAS) MRS allows small esophageal tissue specimens to be studied directly without the need to extract the tissue, but it is not known how intact the tissue architecture remains after MAS. We report the first prospective MAS MRS study of Barrett's esophagus using endoscopic biopsies with direct histological correlation. METHODS: Biopsies were obtained during surveillance esophagoscopy from Barrett's epithelium and adjacent normal squamous epithelium in 16 patients (34 samples). High-resolution MAS MRS was performed at 500 MHz. Following MRS, the histology was evaluated. A further, separate group of 14 biopsies were examined histologically to assess architectural damage caused by tissue preservation alone. RESULTS: For squamous and Barrett's epithelium, respectively, metabolite ratios of choline-containing compounds to creatine plus phosphocreatine (Cho/Cr) were 1.99 and 5.65 (P < 10) and methyl lipid to creatine plus phosphocreatine ratios (lipid-CH3/Cr) were 4.07 and 7.4 (P < 10). There was no significant difference in histological preservation between the squamous and Barrett's mucosa without MRS (z = 0.67, P = 0.61), but significant differences were found post-MAS MRS (z = 4.06, P < 0.0001). CONCLUSIONS: Squamous and Barrett's epithelium can be distinguished metabolically, based on Cho/Cr and lipid-CH3/Cr ratios. Although MAS does affect the histological architecture in Barrett's epithelium, compared with squamous epithelium, direct histological assessment was possible in the majority of samples. 相似文献
86.
87.
Hairy polyps or dermoids are rare, benign congenital tumours of the oronasopharynx containing elements of both ectodermal and mesodermal origin. They occur most commonly in young infants and can cause respiratory distress or failure to thrive due to feeding difficulties. Computed tomography, magnetic resonance imaging, and barium video fluoroscopy can be useful in delineating the origin and extent of these lesions. Treatment usually consists of surgical removal. We describe a case of spontaneous resolution of symptoms in an 11-week-old baby due to autoamputation of the lesion. 相似文献
88.
Puri GD Dutta A Chinnan NK Thingnam SK Sharma SK Chari P 《European journal of anaesthesiology》2005,22(11):834-838
BACKGROUND AND OBJECTIVE: We studied the effect of different recumbent positions (supine, left and right lateral decubitus), on arterial oxygenation in 42 valvular heart disease patients planned for cardiac surgery. All patients had cardiomegaly (cardiothoracic ratio > or = 0.5) in their chest X-rays. Their left ventricular end-diastolic diameter was also noted from the preoperative echocardiogram. METHODS: Arterial blood gas analysis was performed in supine, left and right lateral positions after keeping the patient in a given position for 15 min. During this period all patients received 35% oxygen supplementation. RESULTS: Arterial oxygen tension and haemoglobin saturation were significantly higher in the right lateral position (PaO2 = 120.6 +/- 29.5 mmHg, SaO2 = 98.1 +/- 1.4%) than in supine (PaO2 = 111.0 +/- 30.6 mmHg, SaO2 = 97.6 +/- 2.2%) and left lateral positions (PaO2 = 109.7 +/- 32.0 mmHg, SaO2 = 97.6 +/- 1.7%; mean +/- SD; P 0.05). The change in PaO2 and SaO2 with change of posture from left to right was significantly related to left ventricular end-diastolic diameter (r = 0.50 and r = 0.63, respectively; Pearson correlation). Repeated measures of analysis of variance with left ventricular end-diastolic diameter as a covariate showed a significant change in arterial PaO2 with posture (P = 0.011). CONCLUSION: Right lateral posture improves arterial oxygenation in the valvular heart disease patient with an enlarged left ventricle. In the preoperative period, these patients may benefit from a right lateral posture when lying in bed. 相似文献
89.
90.
Puri BK Saeed N Richardson AJ Oatridge A Hajnal JV Bydder GM 《International journal of clinical practice》2005,59(4):399-402
A cohort of patients with first-episode schizophrenia was dichotomised into two age- and sex-matched groups of clinical syndromes, the active and withdrawn, and underwent high-resolution three-dimensional magnetic resonance imaging at baseline and 8 months later. A cohort of age- and sex-matched normal controls was also imaged at the same time intervals. The application of subvoxel registration and semiautomated quantification techniques demonstrated a significantly different outcome in ventricular changes between the two groups of patients. Compared with the controls, the withdrawn patients showed progressive ventricular enlargement, with an increase in ventricle-to-brain volume ratio, whereas the active group showed a reduction in ventricle-to-brain volume ratio, with a change opposite in sign and smaller in magnitude. These findings lend further support for the aetiological validity of this syndromal model of schizophrenia and are likely to be of importance in furthering our understanding of its pathogenesis and in the development of suitable therapeutic strategies. 相似文献