全文获取类型
收费全文 | 23305篇 |
免费 | 1441篇 |
国内免费 | 113篇 |
专业分类
耳鼻咽喉 | 409篇 |
儿科学 | 591篇 |
妇产科学 | 435篇 |
基础医学 | 3178篇 |
口腔科学 | 1661篇 |
临床医学 | 1765篇 |
内科学 | 5165篇 |
皮肤病学 | 633篇 |
神经病学 | 1655篇 |
特种医学 | 570篇 |
外科学 | 2852篇 |
综合类 | 94篇 |
一般理论 | 4篇 |
预防医学 | 2606篇 |
眼科学 | 356篇 |
药学 | 1544篇 |
中国医学 | 205篇 |
肿瘤学 | 1136篇 |
出版年
2023年 | 272篇 |
2022年 | 550篇 |
2021年 | 1125篇 |
2020年 | 621篇 |
2019年 | 959篇 |
2018年 | 1261篇 |
2017年 | 762篇 |
2016年 | 800篇 |
2015年 | 869篇 |
2014年 | 1126篇 |
2013年 | 1511篇 |
2012年 | 1972篇 |
2011年 | 2184篇 |
2010年 | 1300篇 |
2009年 | 945篇 |
2008年 | 1172篇 |
2007年 | 1087篇 |
2006年 | 957篇 |
2005年 | 826篇 |
2004年 | 683篇 |
2003年 | 598篇 |
2002年 | 492篇 |
2001年 | 397篇 |
2000年 | 357篇 |
1999年 | 321篇 |
1998年 | 127篇 |
1997年 | 94篇 |
1996年 | 83篇 |
1995年 | 41篇 |
1994年 | 51篇 |
1993年 | 36篇 |
1992年 | 138篇 |
1991年 | 118篇 |
1990年 | 85篇 |
1989年 | 96篇 |
1988年 | 85篇 |
1987年 | 57篇 |
1986年 | 78篇 |
1985年 | 57篇 |
1984年 | 56篇 |
1983年 | 43篇 |
1982年 | 27篇 |
1981年 | 23篇 |
1980年 | 30篇 |
1979年 | 45篇 |
1978年 | 31篇 |
1977年 | 24篇 |
1976年 | 33篇 |
1971年 | 22篇 |
1969年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
J. Rodríguez-Carrio A. Martínez-Zapico I. Cabezas-Rodríguez L. Benavente Á.I. Pérez-Álvarez P. López J.B. Cannata-Andía M. Naves-Díaz A. Suárez 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(2):135-143
Background and aims
Since accelerated atherosclerosis has been reported in systemic lupus erythematosus (SLE), predictive biomarkers of cardiovascular disease (CVD) are needed. Among non-traditional risk factors, bone mineral density (BMD) has been related to CVD. However, its role in SLE remains controversial. This study aims to analyze the associations of subclinical atherosclerosis with traditional and non-traditional CV risk factors.Methods and results
In a cross-sectional study, atherosclerosis burden was compared between 112 female SLE patients and 31 controls. Plaque number and carotid intima-media wall thickness (cIMT) were assessed by ultrasonography. In a retrospective study, BMD determinations obtained 5-years before the ultrasonography assessment were analyzed in a subgroup of 62 patients. Plaque frequency was increased in SLE, even in patients without CV events or carotid wall thickening. cIMT was increased in patients with CVD, positively correlated with body mass index (BMI). Interestingly, a paradoxical effect of BMI on carotid parameters was observed. Whereas underweight patients (BMI < 20) showed increased prevalence of carotid plaques with low cIMT, those with BMI > 30 showed higher cIMT and plaque burden. Overweight patients (25 < BMI<30) exhibited both elevated cIMT and plaque number. BMI was an independent predictor of BMD. In our retrospective study, patients with either clinical or subclinical CVD exhibited lower BMD levels than their CV-free counterparts. A low lumbar spine BMD independently predicted CVD development after adjusting for confounders.Conclusion
SLE was associated with a higher subclinical atherosclerosis burden, a bimodal effect being observed for BMI. Decreased BMD can be a CV risk biomarker in SLE. 相似文献3.
P E Santos E Piontelli Y R Shea M L Galluzzo S M Holland M E Zelazko S D Rosenzweig 《Medical mycology》2006,44(8):749-753
Infections due to Penicillium species other than P.marneffei are rare. We identified a boy with X-linked chronic granulomatous disease (X-CGD) with a pulmonary nodule and adjacent rib osteomyelitis caused by Penicillium piceum. The only sign of infection was an elevated sedimentation rate. P. piceum was isolated by fine needle aspirate and from excised infected tissues. Surgical removal and one year of voriconazole treatment were very well tolerated and led to complete recovery. Microbiological, microscopic and molecular studies support the fungal diagnosis. P. piceum should be considered as a relevant pathogen in immunocompromised patients. 相似文献
4.
Adriana B Campaner Alessandro Scapinelli Ruy O Machado Roberto E Dos Santos Geni W Beznos Tsutomu Aoki 《Gynecological endocrinology》2006,22(7):395-398
We report a case of a prepubertal girl with juvenile primary hypothyroidism presenting as ovarian cysts and precocious puberty. The 7-year-old female was referred to our clinic because of a pelvic/abdominal mass and vaginal bleeding. Besides these findings, on physical examination we noticed the thyroid gland globally increased and the presence of secondary sexual characteristics. Based upon the clinical profile and investigations, the patient was diagnosed with juvenile primary hypothyroidism due to autoimmune thyroiditis. The cysts and precocious puberty resolved spontaneously after the simple replacement of thyroid hormone. It is important to bear in mind hypothyroidism in cases of girls presenting ovarian cysts and precocious puberty in order to avoid unnecessary surgery on the ovaries. 相似文献
5.
Afterpotential characteristics and firing patterns in maturing rat hippocampal CA1 neurones in in vitro slices. 总被引:2,自引:0,他引:2
The postnatal evolution of depolarizing after-potentials (DAPs) and after-hyperpolarizations (AHPs) was studied in rat CA1 hippocampal neurones (5-68 days of age) using in vitro slices. Results were pooled into 4 age groups: P5-9, P10-16, P17-24 and P26-68. In P5-9 cells, DAPs were seen as passive signals, with a time constant similar to the time constant of the membrane. The evolution of the DAP was characterized by a decrease in amplitude, an increase in duration and a change in contour. In P10-16 and P17-24 cells, the DAPs often had a plateau or a hump-like shape which increased the probability of firing and the occurrence of spike doublets. The firing pattern and bursting behaviour of P10-16 CA1 neurones differed from the pattern typical of the adult. P5-9 and P10-16 cells had post-burst AHPs with a smaller amplitude and a more prolonged early phase than at late stages of development. 相似文献
6.
Francisco Sampaio Pedro Mateus Nuno Bettencourt Carla Costa Dias Luís Ad?o Lino Santos Madalena Teixeira Lino Sim?es Vasco Gama 《Revista portuguesa de cardiologia》2006,25(3):321-327
INTRODUCTION: Ischemic heart disease is a major cause of heart failure in western societies. However, the factors that may influence left ventricular function (LVF) recovery after an acute coronary syndrome (ACS) are still unclear. OBJECTIVE: To identify variables that may influence LVF evolution one year after ACS. METHODS: 104 patients hospitalized with ACS between 7/1/2001 and 12/31/2002 and with systolic dysfunction--defined as an echocardiographic ejection fraction (EF) < or = 45%--were randomly allocated to a planned coronary follow-up program (FUP) or a general cardiology clinic (GC); patients from both groups were also randomly referred to a structured cardiac rehabilitation program (CRP). EF was re-assessed at one year. We compared differences between patients who recovered left ventricular function (EF > 45%; group 1) and those who did not (group 2). RESULTS: One year after discharge, 44.2% of the patients had recovered function. There were no significant differences between the groups in gender (77.7 vs. 76.5% male), age (56 vs. 59 years), hypertension, diabetes, dyslipidemia, smoking habits or family history. A previous history of cardiovascular events was more frequent in group 2 (11.1% vs. 35.3%, p = 0.03). Cardiac catheterization was performed before discharge in 88.8% and 88.2% in groups 1 and 2 respectively (p = NS); no differences were found in coronary anatomy between the two groups. Angioplasty was performed in 54.2% in group 1 and 50% in group 2 (p = NS). There were no differences in the use of angiotensin-converting enzyme inhibitors (83.3% vs. 87.5%), beta-blockers (87.5% vs. 87.5%), nitrates (37.5% vs. 33.3%), aspirin (95.8% vs. 95.8%), statins (79.1% vs. 75%) or diuretics (20.8% vs. 45.8%). There was no significant difference in LVF recovery between patients randomized to FUP or GC (38.5% vs. 54.5%). 87.5% of patients who completed the CRP had normal EF at one year compared to 32.7% of patients not referred to the program (p = 0.009). Although EF improved in both groups, this improvement was greater in patients who completed a CRP (EF 8% vs. 5%, p = 0.003). CONCLUSION: A previous cardiovascular event and completion of a CRP were the only variables that influenced LVF recovery. Thus, enrollment in a CRP, in addition to standard therapy, could be an important therapeutic measure in patients with systolic dysfunction after ACS; our data suggest that these programs should be more widely used. 相似文献
7.
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
8.
Marcos Ribeiro Luciene Angelini Priscila Games Robles-Ribeiro Rafael Stelmach Ubiratan de Paula Santos Mario Terra-Filho 《The Journal of asthma》2007,44(5):371-375
Background. The European Community Respiratory Health Survey (ECRHS) questionnaire was planned to answer questions about the distribution of asthma. Our objective was to determine the cultural equivalence of the ECRHS into the Brazilian-Portuguese language. Methods. We translated the ECRHS according to international criteria. Results. Small cultural adaptations were necessary. Among the 80 participating patients, the Cronbach indices were higher (0.98-1.00) and the Kappa indices varied from 0.77 to 1.00. Conclusion. The study suggests that the Brazilian version of the ECRHS is conceptually equivalent to the original and similarly reliable and may be used in international studies involving Portuguese-speaking respiratory patients. 相似文献
9.
10.
Mariana Diniz Bisi Santos Arthur Braga Pfeifer Marcos Rogério Pupo Silva Claudio Luiz Sendyk WIlson Roberto Sendyk 《Journal of applied oral science : revista FOB》2007,15(2):148-151
One of the causes of implant failures in cemented implant-retained prostheses is the fracture of abutment screw or UCLA abutment. This article reports a case of simultaneous fracture of two UCLA abutments screws occurring in an implant-supported prosthesis placed in the mandibular molar region. The fractured structures were examined under scanning electron microscopy to investigate the probable causes of the failure, which were not related to failures on materials or fabrication of the screws, but rather were due to shear forces. The misfit in cemented prostheses may be the most likely cause of shear force generation. 相似文献