全文获取类型
收费全文 | 21243篇 |
免费 | 1298篇 |
国内免费 | 139篇 |
专业分类
耳鼻咽喉 | 245篇 |
儿科学 | 628篇 |
妇产科学 | 450篇 |
基础医学 | 3042篇 |
口腔科学 | 1094篇 |
临床医学 | 1759篇 |
内科学 | 4874篇 |
皮肤病学 | 597篇 |
神经病学 | 1952篇 |
特种医学 | 419篇 |
外科学 | 2032篇 |
综合类 | 54篇 |
一般理论 | 10篇 |
预防医学 | 2057篇 |
眼科学 | 373篇 |
药学 | 1585篇 |
中国医学 | 109篇 |
肿瘤学 | 1400篇 |
出版年
2024年 | 36篇 |
2023年 | 266篇 |
2022年 | 675篇 |
2021年 | 1149篇 |
2020年 | 598篇 |
2019年 | 860篇 |
2018年 | 977篇 |
2017年 | 614篇 |
2016年 | 725篇 |
2015年 | 806篇 |
2014年 | 1048篇 |
2013年 | 1270篇 |
2012年 | 1832篇 |
2011年 | 1916篇 |
2010年 | 1123篇 |
2009年 | 819篇 |
2008年 | 1313篇 |
2007年 | 1240篇 |
2006年 | 1077篇 |
2005年 | 977篇 |
2004年 | 790篇 |
2003年 | 701篇 |
2002年 | 647篇 |
2001年 | 155篇 |
2000年 | 133篇 |
1999年 | 140篇 |
1998年 | 110篇 |
1997年 | 88篇 |
1996年 | 54篇 |
1995年 | 39篇 |
1994年 | 40篇 |
1993年 | 33篇 |
1992年 | 50篇 |
1991年 | 39篇 |
1990年 | 32篇 |
1989年 | 25篇 |
1988年 | 23篇 |
1987年 | 25篇 |
1986年 | 25篇 |
1985年 | 17篇 |
1984年 | 15篇 |
1983年 | 18篇 |
1982年 | 18篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 10篇 |
1977年 | 14篇 |
1974年 | 11篇 |
1973年 | 9篇 |
1967年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Gabriela Perdomo Coral Angelo Alves de Mattos 《Journal canadien de gastroenterologie》2003,17(3):187-190
BACKGROUND/AIMS: Spontaneous bacterial peritonitis (SBP) is an important complication in cirrhotic patients. The aim of the present study was to assess the incidence, predictive factors and prognosis for renal impairment (RI) after SBP in cirrhotic patients from southern Brazil. METHODS: Of the 1030 hospitalizations evaluated, 114 episodes of SBP were diagnosed in 94 patients (mean age 49 years; 76.59% men). SBP diagnosis was established when the ascitic fluid polymorphonuclear cell count was equal to or greater than 250 cells/mm3. Five cases were excluded. The variables assessed as possible predictors of steady or progressive RI were blood urea nitrogen and creatinine levels before the diagnosis of SBP; type of infection, antibiotic prophylaxis, first episode or recurrent SBP, presence of gastrointestinal bleeding and hepatic encephalopathy during hospitalization, SBP resolution, Child-Pugh classification, levels of blood pressure, ascitic fluid and blood polymorphonuclear cell count, bacteriological data (positive and negative ascitic fluid culture), albumin, bilirubin, sodium and prothrombin time at the moment of diagnosis. RESULTS: The incidence of SBP was 11.07%. In 61 (55.96%) episodes, SBP was associated with RI (transient in 57.37%; steady in 19.67%; and progressive in 22.95%). The mortality rate associated with progressive RI was 100%; 58.33% with steady RI; and 2.85% with transient RI. The mortality rate in patients with or without RI was 36.07% and 6.25%, respectively (P<0.001). The level of creatinine (greater than or equal to 1.3mg/dL) before the diagnosis of SBP and the rate of infection resolution were the only predictors of RI in the multivariate analysis. CONCLUSIONS: RI after SBP is a common complication, and indicates a poor prognosis for this infection. High levels of creatinine before infection and the rate of infection resolution are independent predictors of RI. 相似文献
2.
Successful efforts in improving breastfeeding initiation rates at an urban teaching hospital prompted the hospital to create a lactation consultant (LC) position in the outpatient setting to focus on breastfeeding duration. This article reviews the complexity of the clinic setting, with the challenges and benefits of the consultant's first year in one of the hospital's outpatient clinics. Preliminary data collected by the consultant suggest that patients counseled by the LC in the outpatient clinic setting have longer breastfeeding duration rates. 相似文献
3.
Mariela Dutra Gontijo Moura Soraya de Mattos Camargo Grossmann Linaena Méricy da Silva Fonseca Maria Inês Barreiros Senna Ricardo Alves Mesquita 《Journal of oral pathology & medicine》2006,35(6):321-326
BACKGROUND: Oral hairy leukoplakia (OHL) may be an indicator of the progression of Human Immunodeficiency Virus (HIV)-induced immuno-depression, and the evaluation of risk factors leading to OHL is important in the management of these HIV-infected patients. However, there are few studies that analyze risk factors leading to OHL in the Brazilian population. The aim of this case-control study is to present data about prevalence rates and risk factors leading to OHL in a sample of HIV-infected adults in Brazil. METHODS: This case-control study included 111 HIV-infected patients treated at a clinic for sexually transmitted diseases and HIV. In the initial examinations with dentists, variables were collected from all patients. Diagnosis of OHL was performed in accordance with the International Classification System and cytological features. The Fisher and the chi-squared tests were used for statistical analysis. The proportional prevalence and odds ratio were estimated. RESULTS: Outcome presented a positive, statistically significant association among the presence of OHL and viral load of 3000 copies/mul or greater (P = 0.0001; odds ratio (OR) = 5.8), presence of oral candidiasis (P = 0.0000; OR = 11.1), previous use of fluconazole (P = 0.0000; OR = 24.6), and use of systemic acyclovir (P = 0.032; OR = 4.3). Antiretroviral medication presented a negative, statistically significant association with the presence of OHL (P = 0.002; OR = 8.4). CONCLUSIONS: Prevalence of OHL was 28.8%. Viral load, oral candidiasis, previous use of fluconazole, and systemic acyclovir were determined to be risk factors for OHL. Antiretroviral medication proved to be protective against the development of OHL. 相似文献
4.
5.
C Pereira Alves 《Phlébologie》1989,42(4):585-589
Varitest plethysmography is a non-invasive diagnostic method of venous insufficiency based on the study of the emptying of leg veins by flexion movements and their subsequent filling. The Varitest records the curves and measurements of these two stages. The physiological bases of the test and its technique are presented. Our experience, following the first few cases, enabled us to identify three main groups of patients:--Patients presenting chronic symptoms, in whom the clinical examination was negative or not obvious;--Patients presenting a problem of differential diagnosis with a deep/superficial or mixed chronic venous insufficiency. It also enabled us to specify the results of the treatments. According to our results, Varitest is a simple, easy to reproduce method, presenting a sensitivity and specificity with regard to the clinical symptoms and the Doppler, of approximately 80%. Its negative aspects are the poor collaboration of the patients or their inability to be available in order to study acute venous thromboses. 相似文献
6.
A Todo-Bom A Mota Pinto V Alves S Vale Pereira M Santos Rosa 《Journal of investigational allergology & clinical immunology》2007,17(2):107-112
BACKGROUND: Asthma is a chronic inflammatory disorder of the airways. The persistence of airway inflammation depends on a decrease in apoptosis of T lymphocytes and eosinophils and survival of these activated cells. T lymphocytes expressing gamma delta receptors can be identified in human lungs and play an important role in immune defence against pathogens and in the regulation of chronic inflammation. Aging is associated with evidence of some immune dysregulation. OBJECTIVE: The aim of this study was to analyze the apoptosis receptors of T lymphocytes in long-lasting asthma, to establish their correlation with activation markers such as CD25+ and human leukocyte antigen (HLA)-DR+, and to analyze the gama delta T cell expression in this disease. METHODS: A group of 64 individuals (group A) who had had asthma for more than 30 years (mean age [+/-SD] 72 +/- 5 years) and 61 healthy individuals acting as controls--group B with 41 individuals (mean age 79 +/- 7 years) and group C with 20 individuals (mean age 38 +/- 12 years) were included in the study. All subjects underwent clinical evaluation and spirometric testing. Peripheral blood cells were stained with monoclonal antibodies anti-CD3, anti-CD4, anti-CD8, anti-CD25, anti-TCR gamma delta, anti-HLA-DR and anti-CD95. Statistical comparisons were performed between the asthmatics and the elderly control group and between the elderly control group and the adult control group. RESULTS: The average percentage of predicted forced expiratory volume in the first second was 73.6 gamma delta 25.3. The mean values of T cell receptors for asthma group A vs elderly control group B vs adult control group C respectively, were the following: CD3, 74.9+/-7 vs. 74.8 +/- 8.8 (P=ns) vs. 76.7 +/- 4.2 (P=ns); CD4, 48.8 +/- 8.7 vs. 43.5 +/- 10.2 (P=ns) vs. 44.8 +/- 3.8 (P=ns); CD8, 23.3 +/- 7.9 vs. 25.7 +/- 10.2 (P=ns) vs. 25.6 +/- 4.5 (P=ns); CD25, 14.3 +/- 5.9 vs. 22.4 +/- 7.8 (P = .0001) vs. 5.5 +/- 2.4 (P = .0001); TCR gamma delta, 2.8 +/- 2.1 vs. 4.1 +/- 3.3 (P < .05) vs. 4.6 +/- 2.1 (P=ns); HLA-DR, 18.4 +/- 9.2 vs. 17.8 +/- 5.9 (P=ns) vs. 15.4 +/- 5.1 (P=ns) and CD95, 49.3 +/- 13.7 vs. 52.6 +/- 12.1 (P=ns) vs. 13.8 +/- 10.8 (P = .0001). CONCLUSIONS: The immunological and inflammatory changes related to ageing may cause an increase in CD95 and CD25 T cell expression. In asthma, blood cells may express increased activation and apoptosis markers but in elderly patients taking steroids, these receptors remain within normal ranges. The number of gamma delta T cells may be lower in long-lasting asthma, and have a limited modulatory effect on allergic inflammatory reactions. The evaluation of patients with long-lasting asthma should take into account the immunological and inflammatory changes present in the elderly in order to avoid results being misinterpreted. 相似文献
7.
8.
9.
We conducted a study of the basal levels of gonadotropins in 38 patients with Turner's syndrome, 14 of whom were using hormone replacement therapy (HRT). The gonadotropin levels were compared with pubertal development and HRT. Seven patients had presented spontaneous menarche; five patients maintained their periods and normal gonadotropin levels, and two developed secondary amenorrhea and high gonadotropin levels. The majority of patients on HRT had high gonadotropin levels. Follicle stimulating hormone (FSH) levels were significantly lower (p = 0.001) in patients with breast development at stage 5, regardless of whether the patient had undergone a spontaneous or a hormonally induced puberty. We concluded that gonadotropin levels are normal in those patients with spontaneous periods, and are high in most patients on HRT; and that FSH levels are significantly lower in those patients with breasts at stage 5. 相似文献
10.
Roberto Rivera-Luna Marta Zapata-Tarrés Aurora Medina-Sansón Enrique López-Aguilar Ana Niembro-Zúñiga J. Amador Zarco Alfonso Marhx-Bracho Fernando Rueda-Franco Leticia Bornstein-Quevedo 《Child's nervous system》2007,23(5):543-547
Objective The purpose of this study is to analyze clinical aspects and disease-free survival (DFS) in children less than 3 years of
age diagnosed with low-grade astrocytoma.
Methods In a period of 24 years (1980–2004), a total of 43 (5.4%) children were registered with these characteristics. Twenty-three
patients had pilocytic astrocytoma, 18 diffused, and 2 mixed. Thirty-one (72.1%) children had incomplete surgical tumor resection
and 12 (27.9%) had a complete tumor resection. Twelve (27.9%) patients had cranial radiotherapy and 17 (39.5%) received chemotherapy.
Overall survival was recorded in 23 (53%). DFS was 50% at 250 months of follow-up for the whole group. DFS for the supratentorial
group was 60% at 250 months, whereas, for the infratentorial, it was 22% at 120 months (p = 0.008).
Conclusion The only favorable prognostic pattern was the supratentorial presentation. Radiotherapy and chemotherapy did not alter the
outcome. 相似文献