全文获取类型
收费全文 | 3212385篇 |
免费 | 245764篇 |
国内免费 | 8152篇 |
专业分类
耳鼻咽喉 | 43696篇 |
儿科学 | 104452篇 |
妇产科学 | 87199篇 |
基础医学 | 462036篇 |
口腔科学 | 89430篇 |
临床医学 | 292684篇 |
内科学 | 629675篇 |
皮肤病学 | 73385篇 |
神经病学 | 257539篇 |
特种医学 | 124062篇 |
外国民族医学 | 743篇 |
外科学 | 488298篇 |
综合类 | 70595篇 |
现状与发展 | 14篇 |
一般理论 | 1167篇 |
预防医学 | 257167篇 |
眼科学 | 73460篇 |
药学 | 235384篇 |
15篇 | |
中国医学 | 5970篇 |
肿瘤学 | 169330篇 |
出版年
2018年 | 35051篇 |
2017年 | 26739篇 |
2016年 | 30741篇 |
2015年 | 34572篇 |
2014年 | 48666篇 |
2013年 | 73522篇 |
2012年 | 97244篇 |
2011年 | 103931篇 |
2010年 | 62875篇 |
2009年 | 60044篇 |
2008年 | 97272篇 |
2007年 | 103790篇 |
2006年 | 105157篇 |
2005年 | 102002篇 |
2004年 | 97326篇 |
2003年 | 94185篇 |
2002年 | 90875篇 |
2001年 | 146410篇 |
2000年 | 150262篇 |
1999年 | 126689篇 |
1998年 | 38030篇 |
1997年 | 33515篇 |
1996年 | 34243篇 |
1995年 | 33248篇 |
1994年 | 30741篇 |
1993年 | 28932篇 |
1992年 | 100962篇 |
1991年 | 98526篇 |
1990年 | 95841篇 |
1989年 | 92026篇 |
1988年 | 84923篇 |
1987年 | 83379篇 |
1986年 | 78504篇 |
1985年 | 75497篇 |
1984年 | 56886篇 |
1983年 | 48321篇 |
1982年 | 29341篇 |
1981年 | 26424篇 |
1979年 | 52195篇 |
1978年 | 37564篇 |
1977年 | 31354篇 |
1976年 | 29695篇 |
1975年 | 31623篇 |
1974年 | 37747篇 |
1973年 | 35908篇 |
1972年 | 33766篇 |
1971年 | 31649篇 |
1970年 | 29010篇 |
1969年 | 27625篇 |
1968年 | 25454篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
881.
Reider N. Issa A. Hawranek T. 《世界核心医学期刊文摘》2006,2(3):48-49
芦荟自古就被用作化妆品和药物添加剂,近来更受喜爱。虽应用广泛,但过敏反应罕有报道。作者用芦荟叶的油性提取物、来自整个植株的芦荟粉及浓缩的芦荟凝胶,对相继就诊的702例患者做斑贴试验。设计专门的问卷调查芦荟的使用、使用原因、使用部位、不良反应、患者职业、个人爱好及是否为遗传性过敏体质。患者均未对任一制剂发生任何反应。需对芦荟所含的两种成分加以鉴别:即芦荟叶皮含有的具有促进肠蠕动、潜在抗菌及抗癌特性的蒽醌类物质。 相似文献
882.
D F du Toit 《SADJ》2003,58(9):375-6, 380-3
The tongue (L. lingua; G. glossa) functions as a digestive organ by facilitating the movement of food during mastication and assisting swallowing. Other important functions include speech and taste. The tongue consists of striated muscle and occupies the floor of the mouth. The dorsal mucosal surface consists of stratified squamous epithelium, with numerous papillae and taste buds. The tongue, a voluntary muscular structure, is attached by a fold, called the frenulum, to the floor of the mouth. Typically, between 8 and 12 circumvallate papillae are arranged in an inverted V-shape towards the base of the tongue. This anatomical review focuses on structure, function relationships and diseases affecting the tongue. From a primary oral health care perspective, this overview will facilitate the process of differential diagnosis in persons presenting with vesiculo-bullous, ulcerative, atrophic and cystic disorders of the tongue. Suspicious lesions should be biopsied to rule out carcinoma. 相似文献
883.
The absence of the temporary incisors could be to a genetic illness or to some multiple premature extractions. These extractions are the aftermaths of the carious lesions or some traumatisms underwent by the temporary incisors. Beyond measure the loss of the space, the premature loss some temporary incisors very often assign the relational development of the child and disturb its psychological development and the aesthetic function. Across some cases clinics, the authors show that the replacement of the temporary incisors is the therapeutic ideal solution. Indeed, the child prosthesis, replacing the temporary absent incisors, solves the psychological, aesthetic and relational problems of the child. 相似文献
884.
We report a case of a six years age girl who presented to our out patients department with the history and findings suggestive of recurrent respiratory tract infections. She was also noticed to have; non homogeneous hyper- pigmented patches on the face since three months of age, sparse hair on the scalp and eyebrows, conical peg like teeth and delayed dentition, prominent and low set ears, perpetually flexed third toe bilaterally. Axillary skin biopsy showed adenexal structures and eccrine glands in subcutaneous fat which were reduced in number. The diagnosis made was: Anhydrotic/ Hypohidrotic type of ectodermal dysplasia. Key words: Ectodermal Dysplasia, Anhidreotic, Hypohidrotic. 相似文献
885.
886.
887.
888.
Contour defects resulting in deformity caused by lack of tissue can be improved by conventional surgery using autologous tissue, but there is always a donor site morbidity. Integra has been available since the early 1980's for use in acute burns and more recently in reconstruction. It has been shown histologically to act as a tissue regeneration template. The regenerated dermis is buried under an autologous thin split-skin graft. In this study, the principle of burying Integra (without the silicone layer) has been applied to deep tissue defects in 12 reconstructive cases. Such regenerated tissues survive at least 3 years after burying. Modification to the technique to avoid visible edges are being developed. 相似文献
889.
Christine E. Marx William T. Trost Lawrence J. Shampine Robert D. Stevens Christine M. Hulette David C. Steffens John F. Ervin Marian I. Butterfield Daniel G. Blazer Mark W. Massing Jeffrey A. Lieberman 《Neuropsychopharmacology》2006,60(12):1287-1294
BACKGROUND: Few data are currently available investigating neurosteroids (NS) in Alzheimer's disease (AD). The NS allopregnanolone may be decreased in serum and plasma in patients with AD, but it is unclear if allopregnanolone is also reduced in brain. Because a number of NS exhibit neuroprotective effects and impact cognitive performance in rodent models, these molecules may be relevant to the pathophysiology of neurodegenerative disorders. We therefore investigated prefrontal cortex (PFC) NS levels in AD. METHODS: Neurosteroid levels (allopregnanolone, pregnenolone, dehydroepiandrosterone [DHEA]) were determined in postmortem PFC in 14 male subjects with AD and 15 cognitively intact male control subjects by gas chromatography/mass spectrometry preceded by high-performance liquid chromatography purification. RESULTS: Subjects with AD exhibit significant reductions in allopregnanolone compared with cognitively intact control subjects (median levels = 2.50 ng/g vs. 5.59 ng/g, respectively; p = .02). Allopregnanolone levels are inversely correlated with neuropathological disease stage (Braak), r = -.49, p = .007. Median DHEA levels are elevated in subjects with AD (p = .01). CONCLUSIONS: Subjects with AD demonstrate significant reductions in PFC allopregnanolone levels, a finding that may be relevant to neuropathological disease stage severity. Neurosteroids may have utility as candidate biomarkers in AD. 相似文献
890.
Maher Saqqur MD Michael D. Hill MD MSc FRCPC Andrei V. Alexandrov MD Jayanta Roy MD Marcia Schebel BSc Andrea Krol BSc Zsolt Garami MD Ashfaq Shuaib MD FRCPC Andrew M. Demchuk MD FRCPC 《Journal of neuroimaging》2006,16(4):323-328
BACKGROUND: Stringent transcranial Doppler (TCD) criteria for diagnosing occlusion are needed for more reliable TCD performance at bedside in the acute stroke setting. SUBJECTS AND METHODS: At three academic stroke centers, we performed TCD examination for patients with symptoms of cerebral ischemia who underwent digital subtraction angiography (DSA). We used a standard insonation protocol with power M-mode Doppler (PMD) TCD (TCD 100 M, Spencer Technologies Inc., Seattle, WA). We collected mean flow velocity (MFV), pulsatility indices (PI), and power M-mode resistance signature (absent, high, or low) in symptomatic middle (MCA), anterior (ACA), posterior (PCA), and in affected (a), ipsilateral (i), and contralateral (c-lat) cerebral arteries. Ratios of aMCA/c-lat MCA, aMCA/iACA, and aMCA/iPCA MFV were subsequently calculated. PMD-TCD flow findings were evaluated with a receiver-operating characteristic (ROC) analysis for angiographically proven MCA occlusion. RESULTS: We studied 120 patients with acute cerebral ischemia with PMD-TCD examinations prior to or immediately after DSA. Lower aMCA velocities pointed to higher probability of occlusion (P= .055). The aMCA/iPCA MFV ratio was superior to the aMCA/iACA ratio and strongly predictive of occlusion at a threshold ratio of 0.5 (RR 2.31 CI(95) 2.13-2.51). High resistance or absent M-mode flow signatures in the proximal MCA were present in 87% of M1 and M2 MCA occlusions (probability 87%). In the presence of a low-resistance PMD signature, obtaining the aMCA/iPCA MFV ratio <0.5 increases probability of occlusion to 87%. Normal MFV ratios and low-resistance M-mode signatures are highly predictive of a negative angiogram for MCA occlusion. CONCLUSION: In acute cerebral ischemia, reliable criteria for proximal MCA occlusion have been developed based on combination of MFV ratios and M-mode flow resistance signatures. Validation of these criteria will require multicenter studies. 相似文献