全文获取类型
收费全文 | 2445篇 |
免费 | 259篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 68篇 |
妇产科学 | 18篇 |
基础医学 | 272篇 |
口腔科学 | 53篇 |
临床医学 | 218篇 |
内科学 | 357篇 |
皮肤病学 | 52篇 |
神经病学 | 166篇 |
特种医学 | 159篇 |
外科学 | 311篇 |
综合类 | 81篇 |
预防医学 | 506篇 |
眼科学 | 122篇 |
药学 | 202篇 |
中国医学 | 18篇 |
肿瘤学 | 107篇 |
出版年
2021年 | 30篇 |
2020年 | 13篇 |
2019年 | 38篇 |
2018年 | 39篇 |
2017年 | 32篇 |
2016年 | 25篇 |
2015年 | 47篇 |
2014年 | 58篇 |
2013年 | 71篇 |
2012年 | 119篇 |
2011年 | 133篇 |
2010年 | 57篇 |
2009年 | 70篇 |
2008年 | 105篇 |
2007年 | 139篇 |
2006年 | 111篇 |
2005年 | 117篇 |
2004年 | 111篇 |
2003年 | 81篇 |
2002年 | 91篇 |
2001年 | 79篇 |
2000年 | 94篇 |
1999年 | 77篇 |
1998年 | 71篇 |
1997年 | 34篇 |
1996年 | 47篇 |
1995年 | 47篇 |
1994年 | 45篇 |
1993年 | 51篇 |
1992年 | 61篇 |
1991年 | 44篇 |
1990年 | 52篇 |
1989年 | 51篇 |
1988年 | 37篇 |
1987年 | 44篇 |
1986年 | 38篇 |
1985年 | 41篇 |
1984年 | 24篇 |
1983年 | 25篇 |
1982年 | 16篇 |
1981年 | 19篇 |
1980年 | 23篇 |
1979年 | 28篇 |
1978年 | 17篇 |
1977年 | 13篇 |
1976年 | 11篇 |
1973年 | 11篇 |
1972年 | 16篇 |
1971年 | 12篇 |
1969年 | 10篇 |
排序方式: 共有2727条查询结果,搜索用时 16 毫秒
101.
Ghannad F Nica D Fulle MI Grenier D Putnins EE Johnston S Eslami A Koivisto L Jiang G McKee MD Häkkinen L Larjava H 《The American journal of pathology》2008,172(5):1271-1286
Integrin alphavbeta6 is generally not expressed in adult epithelia but is induced in wound healing, cancer, and certain fibrotic disorders. Despite this generalized absence, we observed that alphavbeta6 integrin is constitutively expressed in the healthy junctional epithelium linking the gingiva to tooth enamel. Moreover, expression of alphavbeta6 integrin was down-regulated in human periodontal disease, a common medical condition causing tooth loss and also contributing to the development of cardiovascular diseases by increasing the total systemic inflammatory burden. Remarkably, integrin beta6 knockout mice developed classic signs of spontaneous, chronic periodontal disease with characteristic inflammation, epithelial down-growth, pocket formation, and bone loss around the teeth. Integrin alphavbeta6 acts as a major activator of transforming growth factor-beta1 (TGF-beta1), a key anti-inflammatory regulator in the immune system. Co-expression of TGF-beta1 and alphavbeta6 integrin was observed in the healthy junctional epithelium. Moreover, an antibody that blocks alphavbeta6 integrin-mediated activation of TGF-beta1 initiated inflammatory periodontal disease in a rat model of gingival inflammation. Thus, alphavbeta6 integrin is constitutively expressed in the epithelium sealing the gingiva to the tooth and plays a central role in protection against inflammatory periodontal disease through activation of TGF-beta1. 相似文献
102.
103.
104.
Accuracy of Physical Examination,Ankle‐Brachial Index,and Ultrasonography in the Diagnosis of Arterial Injury in Patients With Penetrating Extremity Trauma: A Systematic Review and Meta‐analysis
下载免费PDF全文
![点击此处可从《Academic emergency medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
105.
106.
Daniel McKee Achilleas Thoma Kristy Bailey Joel Fish 《CANADIAN JOURNAL OF PLASTIC SURGERY》2014,22(2):95-98
Hydrofluoric acid (HF) causes a unique chemical burn. Much of the current treatment knowledge of HF burns is derived from case reports, small case series, animal studies and anecdotal evidence. The management can be challenging because clinical presentation and severity of these burns vary widely. Plastic surgeons managing burn patients must have a basic understanding of the pathophysiology, the range of severity in presentation and the current treatment options available for HF burns.The present article reviews the current understanding of the pathophysiology and systemic effects associated with severe HF burns. Furthermore, it distinguishes between minor and life-threatening HF burns and describes several of the basic techniques that are available to treat patients with HF burns. 相似文献
107.
108.
BACKGROUND: The Roma people originated in northern India and have been known in Europe for nearly a thousand years. For much of that time they have been the subjects of discrimination and oppression, culminating in the extermination of half a million Roma in the Nazi death camps. While it is widely believed that the health of Roma people is often poorer than the majority population, these inequalities remain largely unresearched. METHODS: Published literature on the health of the Roma people was identified using Medline. Opinion pieces were excluded, as were papers relating to anthropometry and to genetic markers. The resultant papers were analysed by country of study and by disease type or care group. RESULTS: Some 70% of papers identified related to just three countries; Spain and the Czech and Slovak Republics. Much literature concentrates upon communicable disease or reproductive health. The limited evidence suggests increased morbidity from non-communicable disease, but there is little published on this topic. Evidence on health care, though fragmentary, suggests poorer access to health services and uptake of preventative care. DISCUSSION: Published research on the health needs of the Roma population is sparse. The topics that have received attention suggest a focus on concepts of contagion or social Darwinism, indicating a greater concern with the health needs of the majority populations with which they live. There is a need for both further research into the health of Roma people; with particular emphasis on non-communicable disease; and also for interventions that improve Roma health. Such research must, however, be handled with sensitivity, recognising the social and political context of the society concerned. 相似文献
109.
Mechanical ventilation in preterm infants: neurosonographic and developmental studies. 总被引:5,自引:0,他引:5
L J Graziani A R Spitzer D G Mitchell D A Merton C Stanley N Robinson L McKee 《Pediatrics》1992,90(4):515-522
Surviving preterm infants of less than 34 weeks' gestation who were selected on the basis of serial cranial ultrasonographic findings during their nursery course had repeated neurologic and developmental examinations during late infancy and early childhood that established the presence (n = 46) or absence (n = 205) of spastic forms of cerebral palsy. Of the 205 infants without cerebral palsy, 22 scored abnormally low on standardized developmental testing during early childhood. The need for mechanical ventilation beginning on the first day of life (n = 92) was significantly related to gestational age, birth weight, Apgar scores, patent ductus arteriosus, grade III/IV intracranial hemorrhage, large periventricular cysts, and the development of cerebral palsy. In the 192 mechanically ventilated infants, vaginal bleeding during the third trimester, low Apgar scores, and maximally low PCO2 values during the first 3 days of life were significantly related to large periventricular cysts (n = 41) and cerebral palsy (n = 43), but not to developmental delay in the absence of cerebral palsy (n = 18). The severity of intracranial hemorrhage in mechanically ventilated infants was significantly associated with gestational age and maximally low measurements of PCO2 and pH, but not with Apgar scores or maximally low measurements of PO2. Logistic regression analyses controlling for possible confounding variables disclosed that PCO2 values of less than 17 mm Hg during the first 3 days of life in mechanically ventilated infants were associated with a significantly increased risk of moderate to severe periventricular echodensity, large periventricular cysts, grade III/IV intracranial hemorrhage, and cerebral palsy. Neurosonographic abnormalities were highly predictive of cerebral palsy independent of PCO2 measurements.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
110.
Effects of positive and negative pressure ventilation on cerebral blood volume of newborn infants 总被引:3,自引:0,他引:3
KS Palmer SA Spencer YABD Wickramasinghe T Wright DP Southall P Rolfe 《Acta paediatrica (Oslo, Norway : 1992)》1995,84(2):132-139
The effects of intermittent positive airway and continuous negative extrathoracic pressure ventilation on cerebral blood volume in preterm infants were studied using near infrared spectroscopy. In 12 infants continuous negative extrathoracic pressure caused a median decrease in cerebral blood volume of 0.14ml/100ml brain (95% confidence intervals (CI) 0.035–0.280) compared with no respiratory support. Oxygenated and deoxygenated haemoglobin also decreased, implying increased venous drainage as the main effect. In 17 infants intermittent positive pressure ventilation also caused a median reduction in cerebral blood volume of 0.06 ml/100 ml brain (95% CI 0.010–0.115) compared with endotracheal positive airway pressure. Deoxygenated haemoglobin increased by 0.07 ml/100 ml brain (95% CI 0.010–0.100) while oxygenated haemoglobin decreased by O.lOml/lOOml brain (95% CI 0.005–0.175). The increase in deoxygenated haemoglobin implies decreased venous drainage and the decrease in oxygenated haemoglobin implies that other factors may also be significant. Heart rate, blood pressure and oxygen saturation were monitored continuously and remained stable. 相似文献