全文获取类型
收费全文 | 7517篇 |
免费 | 414篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 111篇 |
儿科学 | 176篇 |
妇产科学 | 130篇 |
基础医学 | 1058篇 |
口腔科学 | 757篇 |
临床医学 | 630篇 |
内科学 | 1505篇 |
皮肤病学 | 211篇 |
神经病学 | 573篇 |
特种医学 | 137篇 |
外科学 | 844篇 |
综合类 | 38篇 |
一般理论 | 3篇 |
预防医学 | 805篇 |
眼科学 | 136篇 |
药学 | 553篇 |
中国医学 | 76篇 |
肿瘤学 | 224篇 |
出版年
2023年 | 92篇 |
2022年 | 160篇 |
2021年 | 298篇 |
2020年 | 178篇 |
2019年 | 250篇 |
2018年 | 310篇 |
2017年 | 212篇 |
2016年 | 242篇 |
2015年 | 272篇 |
2014年 | 348篇 |
2013年 | 394篇 |
2012年 | 633篇 |
2011年 | 666篇 |
2010年 | 325篇 |
2009年 | 285篇 |
2008年 | 492篇 |
2007年 | 455篇 |
2006年 | 385篇 |
2005年 | 336篇 |
2004年 | 266篇 |
2003年 | 233篇 |
2002年 | 210篇 |
2001年 | 128篇 |
2000年 | 118篇 |
1999年 | 124篇 |
1998年 | 31篇 |
1997年 | 20篇 |
1996年 | 20篇 |
1995年 | 23篇 |
1994年 | 12篇 |
1993年 | 15篇 |
1992年 | 38篇 |
1991年 | 43篇 |
1990年 | 28篇 |
1989年 | 28篇 |
1988年 | 33篇 |
1987年 | 19篇 |
1986年 | 14篇 |
1985年 | 17篇 |
1984年 | 18篇 |
1983年 | 11篇 |
1980年 | 15篇 |
1979年 | 16篇 |
1974年 | 16篇 |
1973年 | 14篇 |
1972年 | 8篇 |
1970年 | 14篇 |
1968年 | 9篇 |
1967年 | 12篇 |
1965年 | 10篇 |
排序方式: 共有7967条查询结果,搜索用时 15 毫秒
81.
82.
83.
Bradycardia and syncope as manifestations of partial epilepsy 总被引:5,自引:0,他引:5
L Constantin J B Martins R W Fincham R D Dagli 《Journal of the American College of Cardiology》1990,15(4):900-905
Although transient increases in heart rate typically occur, bradycardia has infrequently been noted in association with partial seizures. Five patients with temporal lobe epilepsy are described in whom sinus bradyarrhythmias and syncope were prominent manifestations of seizure activity. Partial improvement occurred in one of two patients in whom a permanent pacemaker was implanted before a diagnosis of epilepsy was established. Treatment with phenytoin or carbamazepine resulted in nearly complete resolution of symptoms in all five patients. Because pacemaker implantation does not prevent recurrent symptoms, but anticonvulsant therapy does, this experience underscores the importance of considering the diagnosis of partial epilepsy in selected patients with sinus bradyarrhythmias and syncope. 相似文献
84.
Background
Purified water for pharmaceutical purposes must be free of microbial contamination and pyrogens. Even with the additional sanitary and disinfecting treatments applied to the system (sequential operational stages), Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas alcaligenes, Pseudomonas picketti, Flavobacterium aureum, Acinetobacter lowffi and Pseudomonas diminuta were isolated and identified from a thirteen-stage purification system. To evaluate the efficacy of the chemical agents used in the disinfecting process along with those used to adjust chemical characteristics of the system, over the identified bacteria, the kinetic parameter of killing time (D-value) necessary to inactivate 90% of the initial bioburden (decimal reduction time) was experimentally determined. 相似文献85.
Reis AD Fink MC Machado CM Paz Jde P Oliveira RR Tateno AF Machado AF Cardoso MR Pannuti CS;CHIADO RDGV/FAPESP Research Groups 《Revista do Instituto de Medicina Tropical de S?o Paulo》2008,50(1):37-40
A total of 316 samples of nasopharyngeal aspirate from infants up to two years of age with acute respiratory-tract illnesses were processed for detection of respiratory syncytial virus (RSV) using three different techniques: viral isolation, direct immunofluorescence, and PCR. Of the samples, 36 (11.4%) were positive for RSV, considering the three techniques. PCR was the most sensitive technique, providing positive findings in 35/316 (11.1%) of the samples, followed by direct immunofluorescence (25/316, 7.9%) and viral isolation (20/315, 6.3%) (p < 0.001). A sample was positive by immunofluorescence and negative by PCR, and 11 (31.4%) were positive only by RT-PCR. We conclude that RT-PCR is more sensitive than IF and viral isolation to detect RSV in nasopharyngeal aspirate specimens in newborn and infants. 相似文献
86.
Diesel exhaust particulates affect cell signaling,mucin profiles,and apoptosis in trachea explants of Balb/C mice 下载免费PDF全文
Robson Seriani Mara de Souza Junqueira Alessandra Choqueta de Toledo Milton Arruda Martins Marcelo Seckler Adriano Mesquita Alencar Elnara Marcia Negri Luiz Fernando Ferraz Silva Thaís Mauad Paulo Hilário Nascimento Saldiva Mariangela Macchione 《Environmental toxicology》2015,30(11):1297-1308
Particulate matter from diesel exhaust (DEP) has toxic properties and can activate intracellular signaling pathways and induce metabolic changes. This study was conducted to evaluate the activation of extracellular signal‐regulated kinase (ERK) and c‐Jun N‐terminal kinase (JNK) and to analyze the mucin profile (acid (AB+), neutral (PAS+), or mixed (AB/PAS+) mucus) and vacuolization (V) of tracheal explants after treatment with 50 or 100 μg/mL DEP for 30 or 60 min. Western blot analyses showed small increases in ERK1/2 and JNK phosphorylation after 30 min of 100 μg/mL DEP treatment compared with the control. An increase in JNK phosphorylation was observed after 60 min of treatment with 50 μg/mL DEP compared with the control. We did not observe any change in the level of ERK1/2 phosphorylation after treatment with 50 μg/mL DEP. Other groups of tracheas were subjected to histological sectioning and stained with periodic acid‐Schiff (PAS) reagent and Alcian Blue (AB). The stained tissue sections were then subjected to morphometric analysis. The results obtained were compared using ANOVA. Treatment with 50 μg/mL DEP for 30 min or 60 min showed a significant increase (p < 0.001) in the amount of acid mucus, a reduction in neutral mucus, a significant reduction in mixed mucus, and greater vacuolization. Our results suggest that compounds found in DEPs are able to activate acid mucus production and enhance vacuolization and cell signaling pathways, which can lead to airway diseases. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1297–1308, 2015. 相似文献
87.
88.
Margaret P Astin Tanimola Martins Nicky Welton Richard D Neal Peter W Rose William Hamilton 《The British journal of general practice》2015,65(639):e677-e691
Background
Selection of primary care patients for investigation of potential oesophagogastric cancer is difficult, as the symptoms may represent benign conditions, which are also more common.Aim
To review systematically the presenting features of oesophagogastric cancers in primary care, including open-access endoscopy clinics.Design and setting
Systematic review and meta-analysis.Method
MEDLINE®, Embase, the Cochrane Library, and CINAHL were searched for studies of adults who were symptomatic and presented in primary care or open-access endoscopy clinics. Exclusions were being asymptomatic, screening, or recurrent cancers. Data were extracted to estimate the diagnostic performance of features of oesophagogastric cancers and summarised in a meta-analysis.Results
Fourteen studies were identified. The strongest summary sensitivity and specificity estimates were for: dyspepsia 0.42 (95% confidence interval [CI] 0.29 to 0.56) and 0.48 (95% CI = 0.31 to 0.65); pain 0.41 (95% CI = 0.24 to 0.62) and 0.75 (95% CI = 0.51 to 0.89); and dysphagia 0.32 (95% CI = 0.17 to 0.52) and 0.92 (95% CI = 0.81 to 0.97). Summary positive likelihood ratios (LR+) and diagnostic odds ratios were: dyspepsia 0.79 (95% CI = 0.55 to 1.15) and 0.65 (95% CI = 0.32 to 1.33); pain 1.64 (95% CI = 1.20 to 2.24) and 2.09 (95% CI = 1.57 to 2.77); and dysphagia 4.32 (95% CI = 2.46 to 7.58) and 5.91 (95% CI = 3.56 to 9.82). Corresponding LR+ were: anaemia 4.32 (95% CI = 2.64 to 7.08); nausea/vomiting/bloating 1.07 (95% CI = 0.52 to 2.19); reflux 0.78 (95% CI = 0.47 to 1.78) and; weight loss 5.46 (95% CI = 3.47 to 8.60).Conclusion
Dysphagia, weight loss, and anaemia show the strongest association but with relatively low sensitivity and high specificity. The findings support the value of investigation of these symptoms, but also suggest that, in a population of patients who are low risk but not no-risk, investigation is not currently recommended. 相似文献89.
M G Kienzle J B Martins D J Wendt L Constantin R Hopson M L McCue 《The American journal of cardiology》1988,61(13):1012-1017
Sotalol is a nonselective beta-adrenergic blocking agent with Vaughn-Williams class III activity. Its efficacy was tested in 9 patients with sustained ventricular tachycardia (VT) that had previously remained inducible during electrophysiologic testing of type I drugs (procainamide or quinidine). Eight patients had coronary artery disease with remote myocardial infarction and 1 had cardiomyopathy (ejection fraction 0.34 +/- 0.08, mean +/- standard deviation). Type I drugs prolonged the effective refractory period of the right ventricle 12 +/- 14% and prolonged the VT cycle length 41 +/- 24%. In contrast, despite an equivalent effect on the effective refractory period, a sustained VT could no longer be initiated in any of the 8 patients ultimately tested while taking oral sotalol. Daily doses averaged 600 +/- 103 mg and blood levels associated with VT suppression in electrophysiologic studies were generally greater than 3,000 ng/ml. In addition, sotalol was moderately effective at reducing ventricular ectopic activity measured by ambulatory electrocardiography. Over a mean follow-up of 23 months (range 1 to 37), mild heart failure (3 patients), symptomatic brady-cardia requiring pacemaker (1) and drug-related polymorphous VT (1) have occurred. Sudden death occurred in 1 patient and nonfatal VT recurrence was noted in 2. Five of 8 chronically treated patients currently are successfully treated with minimal side effects. Sotalol appears to be a promising antiarrhythmic drug in the treatment of serious ventricular arrhythmias, even in patients refractory to type I antiarrhythmic agents. 相似文献
90.
José Luís Martins Luís Santos Ana Faustino Jesus Viana José Santos 《Revista portuguesa de cardiologia》2018,37(7):595-602