全文获取类型
收费全文 | 1325篇 |
免费 | 51篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 28篇 |
妇产科学 | 35篇 |
基础医学 | 106篇 |
口腔科学 | 53篇 |
临床医学 | 108篇 |
内科学 | 231篇 |
皮肤病学 | 37篇 |
神经病学 | 199篇 |
特种医学 | 99篇 |
外科学 | 256篇 |
综合类 | 3篇 |
预防医学 | 90篇 |
眼科学 | 20篇 |
药学 | 57篇 |
中国医学 | 3篇 |
肿瘤学 | 37篇 |
出版年
2024年 | 2篇 |
2023年 | 13篇 |
2022年 | 18篇 |
2021年 | 27篇 |
2020年 | 27篇 |
2019年 | 20篇 |
2018年 | 32篇 |
2017年 | 24篇 |
2016年 | 21篇 |
2015年 | 24篇 |
2014年 | 45篇 |
2013年 | 67篇 |
2012年 | 89篇 |
2011年 | 86篇 |
2010年 | 61篇 |
2009年 | 48篇 |
2008年 | 73篇 |
2007年 | 92篇 |
2006年 | 97篇 |
2005年 | 108篇 |
2004年 | 81篇 |
2003年 | 74篇 |
2002年 | 64篇 |
2001年 | 13篇 |
2000年 | 20篇 |
1999年 | 11篇 |
1998年 | 10篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 10篇 |
1991年 | 14篇 |
1990年 | 9篇 |
1989年 | 3篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 9篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1977年 | 5篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1968年 | 2篇 |
1959年 | 1篇 |
排序方式: 共有1381条查询结果,搜索用时 31 毫秒
91.
Idiopathic interstitial pneumonias: CT features 总被引:4,自引:0,他引:4
Idiopathic interstitial pneumonias comprise usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP), desquamative interstitial pneumonia (DIP), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), cryptogenic organizing pneumonia (COP), acute interstitial pneumonia (AIP), and lymphoid interstitial pneumonia (LIP). Each of these entities has a typical imaging and histologic pattern, although in practice the imaging patterns may be variable. Each entity may be idiopathic or may be secondary to a recognizable cause such as collagen vascular disease or inhalational exposure. The diagnosis of idiopathic interstitial pneumonia is made by means of correlation of clinical, imaging, and pathologic features. The characteristic computed tomographic (CT) features of UIP are predominantly basal and peripheral reticular pattern with honeycombing and traction bronchiectasis. NSIP is characterized by predominantly basal ground-glass opacity and/or reticular pattern, often with traction bronchiectasis. DIP and RB-ILD are smoking-related lung diseases characterized by ground-glass opacity and centrilobular nodules. COP is characterized by patchy peripheral or peribronchovascular consolidation. AIP manifests as diffuse lung consolidation and ground-glass opacity. LIP is associated with a CT pattern of ground-glass opacity sometimes associated with perivascular cysts. 相似文献
92.
93.
Souza CA Müller NL Flint J Wright JL Churg A 《AJR. American journal of roentgenology》2005,185(6):1531-1539
OBJECTIVE: Characteristic high-resolution CT (HRCT) findings of idiopathic pulmonary fibrosis (IPF) include reticulation, architectural distortion, and honeycombing involving mainly the lung periphery and the lower lobes. In 50% of IPF patients, HRCT is nonspecific. This article illustrates the HRCT findings of IPF correlating with the pathology. CONCLUSION: The spectrum of HRCT manifestations varies from typical findings that allow confident diagnosis to atypical patterns mimicking other diseases, including predominance of ground-glass opacity, consolidation, nodules, and atypical distribution of lesions. 相似文献
94.
Propofol neuroprotection in cerebral ischemia and its effects on low-molecular-weight antioxidants and skilled motor tasks 总被引:5,自引:0,他引:5
BACKGROUND: Propofol is neuroprotective when administered immediately after stroke. The therapeutic window, duration of administration, and antioxidant mechanisms of propofol in neuroprotection are not known. The effects of propofol after stroke were examined in the conscious animal. The authors have previously shown that light propofol anesthesia (25 mg x kg(-1) x h(-1)) for a period of 4 h, even if delayed 1 h after the onset of ischemia, decreases infarct volume 3 days after the stroke. METHODS: Cerebral ischemia was induced in awake Wistar rats by a local intracerebral injection of the potent vasoconstrictor, endothelin (6 pmol in 3 microl) into the striatum. Propofol treatment after ischemia was delayed up to 4 h, and the infusion period shortened from 4 h to 1 h. Infarct volume was assessed 3 or 21 days after the stroke. Neurologic outcome was evaluated on days 14-21 after ischemia. Tissue ascorbate and glutathione concentrations were evaluated at 4 h and 3 days after ischemia. RESULTS: Infarct volumes were reduced 3 days after ischemia when propofol treatment (25 mg x kg(-1) x h(-1)) was delayed for 2 h (0.5+/-0.3 mm3) but not 4 h (2.0+/-0.9 mm3), compared with intralipid controls (2.4 +/- 0.7 mm3). The propofol infusion period of 3 h but not 1 h reduced infarct volume. Propofol treatment did not reduce infarct volume 21 days after the stroke, although motor function improvements (Montoya staircase test) were observed 14-21 days after the stroke. Propofol neuroprotection was independent of tissue ascorbate and glutathione concentrations. CONCLUSIONS: Concurrent or delayed administration of propofol is neuroprotective 3 days after ischemia. Although there were no differences in infarct volume 21 days after ischemia, propofol-treated animals had functional improvements at this time. 相似文献
95.
Does hypervascularity of liver metastases as detected on MRI predict disease progression in breast cancer patients? 总被引:2,自引:0,他引:2
Braga L Semelka RC Pietrobon R Martin D de Barros N Guller U 《AJR. American journal of roentgenology》2004,182(5):1207-1213
OBJECTIVE: The aim of our study was to evaluate the association of the vascularity of liver metastases, as characterized by MRI, and disease progression in breast cancer patients. MATERIALS AND METHODS: Sixteen breast cancer patients with liver metastases who underwent MRI before and after systemic therapy were retrospectively identified. On the basis of comparison of each MRI examination with the previous examination, disease status of the patients was classified as complete response, partial response, stable disease, or progressive disease. Liver metastases were characterized as hyper- or hypovascular on the basis of the degree of enhancement in the arterial, portal, and interstitial phases of imaging after administration of a contrast agent. Fisher's exact test and ordinal logistic regression models, including the type of systemic therapy, presence of multiple metastases, and hormone receptor status, were used to estimate the unadjusted and risk-adjusted association between the presence of hypervascular liver metastases and disease progression. RESULTS: All patients in our sample (n = 16) were women and most (12/16, 75%) were white. Their median age was 51.5 years. In unadjusted analyses, the association between the presence of hypervascular liver metastases and disease progression was statistically significant (p < 0.0001). In multiple logistic regression analyses, hypervascular liver metastases were found to be an independent predictor of disease progression. Patients with hypervascular liver lesions were 20.5 times more likely to experience disease progression than patients without hypervascular metastases (odds ratio, 20.5; 95% confidence interval, 5.1-83.5; p < 0.0001). CONCLUSION: Our analysis provides suggestive evidence that disease progression can be predicted through MRI assessment of the vascularity of liver metastases in patients with breast cancer. 相似文献
96.
A case of tracheobronchopathia osteochondroplastica in a patient with silicosis is reported, showing a rare association of disease. Etiological hypotheses and clinical aspects are discussed. Radiologic, bronchoscopic, and pathologic findings are demonstrated with emphasis on the role of computed tomography (CT) in the diagnosis of this disease. 相似文献
97.
Acute renal failure needing dialysis in the intensive care unit and prognostic scores 总被引:2,自引:0,他引:2
d'Avila DO Cendoroglo Neto M dos Santos OF Schor N Poli de Figueiredo CE 《Renal failure》2004,26(1):59-68
BACKGROUND: Generic prognostic scores used in acute renal failure (ARF) give imprecise results; disease-specific indices applied to distinct populations or intensive care practices becomes inaccurate. The current study evaluates the adequacy of prognostic scores, in patients with severe ARF needing dialysis. METHODS: Known generic (APACHE II) and disease-specific (ATN-ISS) indices were applied to a cohort (n = 280) with ARF needing dialysis, under intensive care. Possible risk factors as causal factors, organ dysfunctions and clinical variables were examined, and a local index assembled by multivariate logistic regression analysis. Area under the receiver operating characteristics (ROC) curves evaluated the indices discriminating capacity. Goodness-of-fit testing and linear regression analysis appraised calibration. Validation was accomplished by the bootstrapping technique. The end-point was hospital mortality. RESULTS: Overall mortality was 85%. Female gender < 44 years (OR: 0.29; 95% CI: 0.10-0.84), liver/obstructive biliary disease (OR: 6.03; 95% CI: 1.65-22.08), being conscious (OR: 0.49; 95% CI: 0.21-1.14), use of vasoactive drug (OR: 3.13; 95% CI: 1.25-7.83), respiratory dysfunction (OR: 5.20; 95% CI: 1.25-7.83) or sepsis (OR: 2.62; 95% CI: 1.14-6.02) were associated with outcome. Areas under the ROC curve of 0.815, 0.652 and 0.814; Goodness-of-fit test P = 0.593, P < 0.001 and P = 0.002; and linear regression R2 = 0.973, R2 = 0.526 and R2 = 0.919 for the local index, APACHE II and ATN-ISS, respectively, indicate better performance by the local index. The local index median area under the ROC curve, by bootstrapping, was 0.820 (95% CI: 0.741-0.907). CONCLUSIONS: APACHE II score was inaccurate, and ATN-ISS poorly calibrated. When mortality or intensive care practices significantly deviate, local scores may better evaluate prognosis in severe ARF. 相似文献
98.
An integrative model of the neurophysiology of aggression and social withdrawal is proposed. A detailed overview of the limbic-hypothalamic-pituitary-adrenal (LHPA) axis is presented first, because we consider it to be a critical system that interacts with a variety of physiological processes to modulate affect-related behaviors. This detailed analysis of the LHPA axis is then used to clarify the research literature that links aggression and social withdrawal to LHPA functioning. We then review the role of amygdala and prefrontal cortex functioning in modulating aggression and social withdrawal. Particular attention is paid to how the amygdala and the prefrontal cortex interact with the LHPA system and the environment to produce specific behavioral tendencies throughout development. A brief overview of the implied methodological and theoretical model is provided. We explain how a detailed understanding of specific physiological processes is essential in order to develop appropriate research protocols. In addition, we suggest that future research should focus on the mapping of distinct integrative biosocial profiles that are related to specific behaviors during different developmental stages. 相似文献
99.
Role of myostatin in metabolism 总被引:1,自引:0,他引:1
100.