全文获取类型
收费全文 | 5123篇 |
免费 | 302篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 64篇 |
儿科学 | 91篇 |
妇产科学 | 67篇 |
基础医学 | 744篇 |
口腔科学 | 345篇 |
临床医学 | 433篇 |
内科学 | 1047篇 |
皮肤病学 | 113篇 |
神经病学 | 448篇 |
特种医学 | 175篇 |
外科学 | 604篇 |
综合类 | 34篇 |
一般理论 | 1篇 |
预防医学 | 561篇 |
眼科学 | 61篇 |
药学 | 465篇 |
中国医学 | 32篇 |
肿瘤学 | 190篇 |
出版年
2023年 | 50篇 |
2022年 | 124篇 |
2021年 | 165篇 |
2020年 | 126篇 |
2019年 | 131篇 |
2018年 | 181篇 |
2017年 | 139篇 |
2016年 | 144篇 |
2015年 | 167篇 |
2014年 | 232篇 |
2013年 | 297篇 |
2012年 | 424篇 |
2011年 | 440篇 |
2010年 | 210篇 |
2009年 | 225篇 |
2008年 | 333篇 |
2007年 | 322篇 |
2006年 | 280篇 |
2005年 | 217篇 |
2004年 | 159篇 |
2003年 | 159篇 |
2002年 | 151篇 |
2001年 | 116篇 |
2000年 | 103篇 |
1999年 | 85篇 |
1998年 | 40篇 |
1997年 | 38篇 |
1996年 | 26篇 |
1995年 | 28篇 |
1994年 | 33篇 |
1993年 | 23篇 |
1992年 | 30篇 |
1991年 | 22篇 |
1990年 | 22篇 |
1989年 | 20篇 |
1988年 | 12篇 |
1987年 | 22篇 |
1986年 | 19篇 |
1985年 | 12篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 13篇 |
1980年 | 7篇 |
1979年 | 10篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1969年 | 20篇 |
1967年 | 8篇 |
排序方式: 共有5475条查询结果,搜索用时 15 毫秒
991.
992.
Interfacial evaluation of experimentally weakened roots restored with adhesive materials and fibre posts: an SEM analysis 总被引:1,自引:0,他引:1
da Silveira Teixeira C Santos Felippe MC Silva-Sousa YT de Sousa-Neto MD 《Journal of dentistry》2008,36(9):672-682
OBJECTIVES: To evaluate the bonding interface in experimentally weakened roots reinforced with adhesive restorative materials and quartz fibre posts, varying the light-exposure time of the composite resin used for root reinforcement. METHODS: Twelve extracted human maxillary incisors teeth were used. The crowns were removed and the roots were endodontically treated. After post space preparation, the roots were assigned to four groups. The thickness of the root dentine was reduced and adhesively restored with composite resin light-activated through a translucent fibre post for either 40s (group 1), 80s (group 2) or 120s (group 3). In the case of control (group 4), the roots were not weakened. One day after post cementation, the specimens were sectioned transversally in three slices and processed for scanning electron microscopic analysis to observe bonding interface formation, quality of the hybrid layer and density of resin tags using a four-step scale method. RESULTS: Formation of a hybrid layer and resin tags were evident in all groups. There was no statistically (p>0.05) significant difference between the regions analysed in each group (Friedman test) and between groups in each section depth (Kruskal-Wallis test). Furthermore, comparison of the flared/reinforced groups showed that the different times used for composite resin cure did not affect the results significantly (Kruskal-Wallis test, p=0.2139). CONCLUSIONS: Different light-exposure times used for composite resin polymerisation during root canal reinforcement did not affect significantly the formation and quality of the dentine/adhesive/composite resin bonding interface. 相似文献
993.
Barros MB Costa DL Schubach TM do Valle AC Lorenzi NP Teixeira JL Schubach Ade O 《The Pediatric infectious disease journal》2008,27(3):246-250
BACKGROUND: Sporotrichosis in childhood is rare in most countries. Isolated cases and small outbreaks related to recreational activities or without identification of the transmission mechanism have been reported. METHODS: Series of case reports. The isolation of Sporothrix schenckii from exudates or fragments of lesions obtained from the patients was used as the criterion of inclusion in the study. RESULTS: A total of 81 cases of sporotrichosis in children younger than 15 years of age were diagnosed at the Evandro Chagas Research Institute, Fiocruz, Brazil, between 1998 and 2004. These cases are part of the endemic disease occurring in Rio de Janeiro related to contact with domestic cats. There was a predominance of girls in the 10-14 year age group. The most frequent clinical form was the cutaneouslymphatic form located on the upper limbs. Itraconazole was used as the first-choice treatment. Sixty-six patients were cured, 9 were lost to follow-up, and 6 had spontaneous regression of the lesions. CONCLUSIONS: This is the largest series of childhood sporotrichosis with zoonotic transmission. The clinical presentation of sporotrichosis in children followed the same pattern of the disease in adults in this ongoing endemic. 相似文献
994.
Almeida MC Assunção RM Proietti FA Caiaffa WT 《Cadernos de saúde pública / Ministério da Saúde, Funda??o Oswaldo Cruz, Escola Nacional de Saúde Pública》2008,24(10):2385-2395
This study aimed to describe the temporal-spatial patterns of dengue epidemics in Belo Horizonte, Minas Gerais State, Brazil, from 1996 to 2002 and to analyze residential address as a proxy for exposure. Reported dengue cases were analyzed according to week of onset of symptoms and residential census tract. Local Moran's index was used to assess spatial autocorrelation of incidence coefficients, and recurrent census areas over different epidemic waves were also verified. Ripley's K-function was used to compare spatial distribution patterns between the two population groups, assuming that they were distributed differently around the city. A total of 99,559 dengue cases were analyzed, resulting in seven epidemic waves with different durations and intensities, with cases clustering in a small fraction of areas, thinning out both spatially and temporally. Distinct case distribution patterns were observed according to the two exposed groups, suggesting the need to improve the reporting of possible place of infection. The observed endemic pattern of the disease also requires specific strategies and poses a major challenge for health surveillance services. 相似文献
995.
Lopes AC Oliveira AC Silva JT Paiva MH 《Cadernos de saúde pública / Ministério da Saúde, Funda??o Oswaldo Cruz, Escola Nacional de Saúde Pública》2008,24(6):1387-1396
This was a cross-sectional study of workers in the pre-hospital care team in Belo Horizonte, Minas Gerais State, Brazil, aimed at evaluating adherence to precautions. The study instrument included questions on knowledge, attitudes, and facilitating factors for adherence to standard precautions. Adherence was verified by percentage of adequacy: > 75% correct answers. Drivers showed the lowest degree of knowledge and physicians the highest. In self-reported answers, none of the workers demonstrated adequate use of face masks, goggles, or personal protective equipment (PPE), and drivers reported inadequate attitudes on all the items. In the univariate analysis, job position, gender, and specific rescue unit were associated with adoption of precautions. Meanwhile, in the multivariate analysis, only job position was related (drivers and nurse technicians/aides). The most frequently cited facilitating factors for improvement of adherence were: training focusing on infections, occupational risks, and use of PPE; periodic team meetings; and creation of a central unit for cleaning, disinfecting, and sterilizing equipment and materials. Workers in the pre-hospital care service demonstrated attitudes that were compatible with knowledge, but professional class affected knowledge on standard precautions and self-reported adequate attitudes. 相似文献
996.
This study reports the results of 12 focus group interviews with primary school students (7-10 years old, n=57) in Florianópolis, Brazil, regarding their food choices, television (TV) viewing, and physical activity habits. In 2005, an average Brazilian child aged 4-11 years watched TV almost 5 h per day. Intensive TV use in childhood and adolescence may contribute to sedentarism and unhealthy eating habits, and excessive viewing might have long-lasting adverse effects on health. Results indicated that frequent ingestion of snack foods was not a habit for most students, possibly because of an acknowledged parental interference, but these were the food items they bought with their own money. Daily TV viewing was reported by almost all students, especially during meals and before bedtime, but students still found the time to be physically active. Most of them mentioned going to sports classes and engaging in active play regularly. No attempts by the parents to regulate TV viewing in the household were mentioned. The habit of eating while watching TV, together with the students' behavior as primary consumers of food products, pointed to the need for strategies that will reduce TV viewing and educate the children as consumers. 相似文献
997.
The aim was to evaluate the effect of control selection on risk factor analysis for extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KP) infections. Four contemporaneous case-control studies were conducted prospectively with 372 patients: Study 1 (ESBL-KP-infected vs non-infected); Study 2 (ESBL-KP-infected vs non-ESBL-KP-infected); Study 3 (all KP-infected vs non-infected); Study 4 (non-ESBL-KP-infected vs non-infected). Time at risk (TAR, i.e. duration of hospital stay) was the most significant risk factor [Study 1: odds ratio (OR): 5.74 (95% CI: 2.26-14.59; P<0.001); Study 2: 3.52 (1.47-8.43; P=0.005); Study 3: 2.68 (1.57-4.58; P<0.001)]; central venous catheterisation (CVC) was a risk factor in Study 1: 5.31 (1.67-16.82; P=0.005) and Study 3: 2.10 (1.04-4.27; P=0.04). Prior use of cephalosporins (PUC) was a risk factor only in studies with non-infected patients as controls [Study 1: 5.64 (1.90-16.72; P=0.002) and Study 3: 4.60 (2.09-10.13; P<0.001)]. The ORs were uniformly lower with 'non-ESBL-KP-infected' (TAR: 3.52; CVC: 2.07; PUC: 1.97) compared with 'non-infected' patients (TAR: 5.74; CVC: 5.31; PUC: 5.64) as control groups. Selection of control patients has a crucial role in the evaluation of risk factors for ESBL-KP infections. A consistent underestimation of the magnitude of the risk factors is observed when the control group is defined by the non-ESBL-KP-infected patients. 相似文献
998.
Correlation Between Pesticide Use in Agriculture and Adverse Birth Outcomes in Brazil: An Ecological Study 总被引:1,自引:0,他引:1
Marília Teixeira de Siqueira Cynthia Braga José Eulálio Cabral-Filho Lia Giraldo da Silva Augusto José Natal Figueiroa Ariani Impieri Souza 《Bulletin of environmental contamination and toxicology》2010,84(6):647-651
This ecological study analyzed the association between pesticide use and prematurity, low weight and congenital abnormality
at birth, infant death by congenital abnormality, and fetal death in Brazil in 2001. Simple linear regression analysis has
determined a positive association between pesticide use and prematurity, low birth weight, and congenital abnormality. The
association between pesticide use and low birth weight (p = 0.045) and, congenital abnormality (p = 0.004) and infant death rate by congenital abnormality (p = 0.039) remained after the adjustment made by the proportion of pregnant women with a low number of prenatal care visits. 相似文献
999.
1000.
Selecting suitable solid organ transplant donors: Reducing the risk of donor-transmitted infections 总被引:1,自引:0,他引:1
Christopher S Kovacs Jr Christine E Koval David van Duin Amanda Guedes de Morais Blanca E Gonzalez Robin K Avery Steven D Mawhorter Kyle D Brizendine Eric D Cober Cyndee Miranda Rabin K Shrestha Lucileia Teixeira Sherif B Mossad 《World Journal of Transplantation》2014,4(2):43-56
Selection of the appropriate donor is essential to a successful allograft recipient outcome for solid organ transplantation. Multiple infectious diseases have been transmitted from the donor to the recipient via transplantation. Donor-transmitted infections cause increased morbidity and mortality to the recipient. In recent years, a series of high-profile transmissions of infections have occurred in organ recipients prompting increased attention on the process of improving the selection of an appropriate donor that balances the shortage of needed allografts with an approach that mitigates the risk of donor-transmitted infection to the recipient. Important advances focused on improving donor screening diagnostics, using previously excluded high-risk donors, and individualizing the selection of allografts to recipients based on their prior infection history are serving to increase the donor pool and improve outcomes after transplant. This article serves to review the relevant literature surrounding this topic and to provide a suggested approach to the selection of an appropriate solid organ transplant donor. 相似文献