全文获取类型
收费全文 | 3389589篇 |
免费 | 243452篇 |
国内免费 | 9109篇 |
专业分类
耳鼻咽喉 | 45575篇 |
儿科学 | 112380篇 |
妇产科学 | 93090篇 |
基础医学 | 479572篇 |
口腔科学 | 94438篇 |
临床医学 | 308549篇 |
内科学 | 667484篇 |
皮肤病学 | 80692篇 |
神经病学 | 279197篇 |
特种医学 | 128280篇 |
外国民族医学 | 1085篇 |
外科学 | 501771篇 |
综合类 | 68309篇 |
现状与发展 | 5篇 |
一般理论 | 1315篇 |
预防医学 | 265618篇 |
眼科学 | 75816篇 |
药学 | 246696篇 |
11篇 | |
中国医学 | 7167篇 |
肿瘤学 | 185100篇 |
出版年
2021年 | 28213篇 |
2019年 | 29128篇 |
2018年 | 41698篇 |
2017年 | 31328篇 |
2016年 | 35432篇 |
2015年 | 39877篇 |
2014年 | 54094篇 |
2013年 | 81841篇 |
2012年 | 111329篇 |
2011年 | 117425篇 |
2010年 | 69405篇 |
2009年 | 65168篇 |
2008年 | 108192篇 |
2007年 | 114872篇 |
2006年 | 115872篇 |
2005年 | 111508篇 |
2004年 | 107215篇 |
2003年 | 103174篇 |
2002年 | 99157篇 |
2001年 | 155723篇 |
2000年 | 159580篇 |
1999年 | 134772篇 |
1998年 | 38919篇 |
1997年 | 34638篇 |
1996年 | 34560篇 |
1995年 | 33471篇 |
1994年 | 30816篇 |
1993年 | 28723篇 |
1992年 | 105131篇 |
1991年 | 101472篇 |
1990年 | 98643篇 |
1989年 | 95170篇 |
1988年 | 87073篇 |
1987年 | 85798篇 |
1986年 | 80371篇 |
1985年 | 76977篇 |
1984年 | 57452篇 |
1983年 | 48681篇 |
1982年 | 29032篇 |
1979年 | 51216篇 |
1978年 | 36430篇 |
1977年 | 30912篇 |
1976年 | 28791篇 |
1975年 | 30608篇 |
1974年 | 36511篇 |
1973年 | 34824篇 |
1972年 | 32419篇 |
1971年 | 30206篇 |
1970年 | 27903篇 |
1969年 | 26653篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
991.
Kragh Thomsen M. Rasmussen M. Fuursted K. 《世界核心医学期刊文摘》2006,2(9):2-22
2000年11月,作者得知从Aarhus大学医院皮肤科患者分离到的金黄色葡萄球菌对苯唑西林出现界线耐药(BORSA)。本文旨在描述其表型和基因型,并评估可能的传播途径以干预和阻止进一步蔓延。菌株由脉冲场凝胶电泳鉴定。几个感染控制方案的缺口显示患者间可直接或间接传播。皮肤屏障缺陷、皮肤病患者金黄色葡萄球菌的高携带率和院内双氯西林的高消耗率可促使传播。改善普通感染控制措施和重新评价院内抗生素政策后,该菌的暴发感染消失。 相似文献
992.
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
993.
Bifid mandibular canal. 总被引:1,自引:0,他引:1
PURPOSE: To determine the incidence and characteristics of bifid mandibular canals. METHODS: A retrospective study was performed using panoramic radiographs of 2012 patients subjected to dental treatment in the Dental Clinic of the Valencia University Dental School (Valencia, Spain) between 1996 and 1999. The goal was to investigate the presence of double mandibular canals. RESULTS: The extraoral panoramic radiographs revealed a total of 7 images suggestive of bifid canals. Mandibular computed tomography revealed the existence of this anatomic variant in 2 of 3 patients. An analysis was performed on the incidence of this type of image in extraoral panoramic radiography, its possible interpretations, and the clinical implications of bifid mandibular canals. CONCLUSIONS: In this study, 0.35% of canals were bifid. All cases were in women. 相似文献
994.
995.
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
996.
Victor Aboyans Louis Labrousse Philippe Lacroix Jér?me Guilloux Seifeddine Sekkal Alexandre Le Guyader Elisabeth Cornu Marc Laskar 《European journal of cardio-thoracic surgery》2006,30(2):300-304
BACKGROUND: Despite major improvement in surgical techniques and intensive care management, stroke remains one of the most devastating complications of coronary artery bypass grafting (CABG). We aimed to determine factors predicting the occurrence of stroke during CABG. A special interest was focused on preoperative therapies. METHODS: We prospectively enrolled 810 consecutive candidates for CABG alone in a specific database, including all pre- and perioperative data (history, clinical, therapeutic, cardiac catheterization, surgical and intensive care data). Univariate tests and then multiple logistic regression analysis were used to determine independent predictive factors. RESULTS: During the first postoperative month, stroke occurred in 11 cases and transient ischemic attack (TIA) in 4 additive cases (cumulative rate: 1.85%). After the multivariate analysis, the following factors remained significant (p<0.05) in the predictive model, with corresponding odds ratios between brackets: redo cardiac surgery (7.45), unstable cardiac status (4.74), past history of cerebrovascular disease (4.14), past history of peripheral arterial disease (3.55), whereas the presence of preoperative statins was protective (0.24, 95% IC: 0.07-0.78). The addition of perioperative data (aortic calcification, postoperative arrhythmia, on/off-pump surgery) did not change the final predictive model. CONCLUSION: To our knowledge, this is the first real-world observational report highlighting the interest of statins for the prevention of stroke in the very special situation of CABG. Even though according to randomized trials coronary patients have a benefit from these drugs, a special level of interest should be directed towards those presenting the above-mentioned risk factors. 相似文献
997.
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
998.
Summary The third-stage larvae of Daniconema anguillae Moravec et K?ie, 1987 are found in the eels fins caught from Dringis Lake (Lithuanian National park). The morphology of these
larvae is briefly described. 相似文献
999.
1000.