全文获取类型
收费全文 | 769篇 |
免费 | 62篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 59篇 |
妇产科学 | 57篇 |
基础医学 | 103篇 |
口腔科学 | 9篇 |
临床医学 | 60篇 |
内科学 | 160篇 |
皮肤病学 | 13篇 |
神经病学 | 65篇 |
特种医学 | 42篇 |
外科学 | 116篇 |
综合类 | 9篇 |
预防医学 | 34篇 |
眼科学 | 14篇 |
药学 | 36篇 |
中国医学 | 3篇 |
肿瘤学 | 52篇 |
出版年
2023年 | 6篇 |
2022年 | 4篇 |
2021年 | 20篇 |
2020年 | 7篇 |
2019年 | 15篇 |
2018年 | 16篇 |
2017年 | 14篇 |
2016年 | 21篇 |
2015年 | 32篇 |
2014年 | 26篇 |
2013年 | 40篇 |
2012年 | 61篇 |
2011年 | 49篇 |
2010年 | 40篇 |
2009年 | 38篇 |
2008年 | 39篇 |
2007年 | 38篇 |
2006年 | 35篇 |
2005年 | 38篇 |
2004年 | 30篇 |
2003年 | 24篇 |
2002年 | 15篇 |
2001年 | 16篇 |
2000年 | 27篇 |
1999年 | 17篇 |
1998年 | 17篇 |
1997年 | 7篇 |
1996年 | 21篇 |
1995年 | 14篇 |
1994年 | 15篇 |
1993年 | 14篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 11篇 |
1987年 | 2篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1969年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有833条查询结果,搜索用时 15 毫秒
41.
Polymorphic locus in the 5'-flanking region of human insulin gene and non-insulin-dependent diabetes mellitus 总被引:1,自引:0,他引:1
The etiology of non-insulin-dependent diabetes mellitus (NIDDM) is still unclear, but appears to involve some genetic factors. There have been disputes over the association between DNA sequences flanking the insulin gene and NIDDM. In order to characterize insulin gene polymorphism in the Chinese population and elucidate its association with NIDDM, 100 unrelated Chinese subjects living in Taiwan were observed for polymorphism of this hypervariable region. Most of them were descendants of immigrants from the southern part of mainland China. Among them, 52 were nondiabetic controls, and 48 were subjects with NIDDM. Insulin gene polymorphism was classified into classes 1, 2 and 3 alleles according to Bell et al. Neither the class 2 allele nor the genotype for the homozygous class 3 allele was not observed in this study. The allelic frequencies of class 1 and 3 genes were 97% and 3% in the nondiabetic subjects, and 99% and 1% in the NIDDM group, respectively. The frequencies of genotypes 1/1 and 1/3 were 94% and 6% in nondiabetics and 98% and 2% in the NIDDM group, respectively. No significant association was found between insulin gene polymorphism and NIDDM. It is concluded that DNA marker flanking the insulin gene may not be associated with the development of NIDDM in Chinese subjects. 相似文献
42.
The frequency of reversible and irreversible visual impairment was determined in children with severe and profound sensorineural deafness, as subnormal vision can adversely affect their educational and social development. Eighty three of 87 such children attending an audiology service were examined to assess the incidence and severity of visual impairment. Each child underwent a detailed ophthalmic assessment. The criteria for visual impairment were visual acuity < 6/9 Snellen or equivalent and/or abnormal binocular vision. Forty five had a normal ophthalmic examination (54.2%). Twenty nine had visual impairment (34.9%) and nine had ophthalmological abnormalities that did not interfere with vision (10.9%). A higher proportion of children with risk factors for visual pathology demonstrated visual impairment than those in whom there were no risk factors. None the less, 44% of visual impairment was among patients without risk factors. The results underline the need to examine all children with severe and profound sensorineural deafness soon after diagnosis and indicate that children with multiple handicaps have a greater likelihood of visual impairment (11 of 14 cases). 相似文献
43.
44.
Jou HJ Shyu MK Shih JC Chang MY Lim CC Tzeng CY Chen SM Hsieh FJ 《The Journal of maternal-fetal medicine》2000,9(2):118-121
OBJECTIVE: To establish normative data of maternal serum chorionic gonadotropin (hCG) during the second trimester in an Asian population. METHODS: We measured the maternal serum hCG levels in 17,955 normal singleton pregnancies between 15 and 21 weeks of gestation. The gestation age was estimated by measurement of fetal biparietal distance (BPD) in all cases. Median values of hCG at various gestational weeks were calculated and the values of hCG were converted to multiple of median (MoM). The incidences of low MoM value and high MoM value were also calculated. RESULTS: The mean and median values of hCG were 57,153 mIU/ml and 50,120 mIU/ml, respectively, at 15 weeks of gestation and then decreased to 30,898 mIU/ml and 26,226 mIU/ml, respectively, at 21 weeks. We found 8.6% and 9.4% of normal singleton pregnancies have hCG MoM values >2.0 MoM and <0.5 MoM, respectively. CONCLUSIONS: Our report provides a normal reference data of second trimester maternal hCG levels by ultrasound dating in an Asian population. 相似文献
45.
The coeliac iceberg in Italy. A multicentre antigliadin antibodies screening for coeliac disease in school-age subjects 总被引:8,自引:0,他引:8
C Catassi E Fabiani IM Rätsch GV Coppa PL Giorgi R Pierdomenico S Alessandrini G Iwanejko R Domenici E Mei A Miano M Marani G Bottaro M Spina M Dotti A Montanelli M Barbato F Viola R Lazzari M Vallini G Guariso M Plebani F Cataldo G Traverso C Ughi G Chiaravalloti M Baldassarre P Scarcella F Bascietto L Ceglie A Valenti P Paolucci M Caradonna E Bravi A Ventura 《Acta paediatrica (Oslo, Norway : 1992)》1996,85(S412):29-35
Background : Recent studies suggest that coeliac disease (CD) is one of the commonest, life-long disorders in Italy. The aims of this multicentre work were: (a) to establish the prevalence of CD on a nationwide basis; and (b) to characterize the CD clinical spectrum in Italy. Patients and methods : Fifteen centres screened 17201 students aged 6–15 years (68.6% of the eligible population) by the combined determination of serum IgG- and IgA-antigliadin antibody (AGA) test; 1289 (7.5%) were IgG and/or IgA-AGA positive and were recalled for the second-level investigation; 111 of them met the criteria for the intestinal biopsy: IgA-AGA positivity and/or AEA positivity or IgG-AGA positivity plus serum IgA deficiency. Results : Intestinal biopsy was performed on 98 of the 111 subjects. CD was diagnosed in 82 subjects (75 biopsy proven, 7 not biopsied but with associated AGA and AEA positivity). Most of the screening-detected coeliac patients showed low-grade intensity illness often associated with decreased psychophysical well-being. There were two AEA negative cases with associated CD and IgA deficiency. The prevalence of undiagnosed CD was 4.77 × 1000 (95% CI 3.79–5.91), 1 in 210 subjects. The overall prevalence of CD, including known CD cases, was 5.44 × 1000 (95% CI 4.57–6.44), 1 in 184 subjects. The ratio of known to undiagnosed CD cases was 1 in 7. Conclusions : These findings confirm that, in Italy, CD is one of the most common chronic disorders showing a wide and heterogeneous clinical spectrum. Most CD cases remain undiagnosed unless actively searched. 相似文献
46.
PURPOSE: Incidence data for severe aplastic anaemia (SAA) in children are scanty and vary. Few population based studies have been reported. A retrospective and prospective study was conducted to determine the incidence and course of SAA. PATIENTS AND METHODS: All children with a diagnosis of SAA in the Nordic countries from 1982 through 1993 were registered and have been followed up since 1987. RESULTS: A total of 101 children were diagnosed with SAA. The mean annual child population was 4.31 million. A constant incidence of 1.95/million children/year was found: 2.4 for boys and 1.5 for girls. A non-significant increase of cases occurred from November to March. Possible aetiological agents were noted in 29%. The actuarial survival was 79% after one year and 68% after five years without significant difference between boys and girls. CONCLUSION: The incidence of SAA in the Nordic countries remains stable with a preponderance among boys. SAA has still a high initial mortality and a risk of late deaths. 相似文献
47.
48.
Lorthois S Stroud-Rossman J Berger S Jou LD Saloner D 《Annals of biomedical engineering》2005,33(3):270-283
Magnetic Resonance Angiography (MRA) has become a routine imaging modality for the clinical evaluation of obstructive vascular disease. However, complex circulatory flow patterns, which redistribute the Magnetic Resonance (MR) signal in a complicated way, may generate flow artifacts and impair image quality. Numerical simulation of MRAs is a useful tool to study the mechanisms of artifactual signal production. The present study proposes a new approach to perform such simulations, applicable to complex anatomically realistic vascular geometries. Both the Navier-Stokes and the Bloch equations are solved on the same mesh to obtain the distribution of modulus and phase of the magnetization. The simulated angiography is subsequently constructed by a simple geometric procedure mapping the physical plane into the MRA image plane. Steady bidimensional numerical simulations of MRAs of an anatomically realistic severely stenotic carotid artery bifurcation are presented, for both time-of-flight and contrast-enhanced imaging modalities. These simulations are validated by qualitative comparison with flow phantom experiments performed under comparable conditions. 相似文献
49.
A retrospective study was conducted to assess the effectiveness and tolerability of atomoxetine in children and adolescents with pervasive developmental disorders (PDD). An outpatient clinic registry of individuals with PDD was used to identify all children and adolescents who received atomoxetine over a period of 12 months. Patients were included if concomitant medications remained unchanged. Treatment response was assessed using the Global Improvement item of the Clinical Global Impressions scale (CGI-GI) based on the Conners Parent Rating Scale (CPRS) routinely completed by primary caretakers and other clinical information available in the registry. Twenty patients were identified, including 16 males and 4 females (age, 11.5 years; standard deviation, 3.5). Most patients (80%) were taking at least 1 concomitant medication. Treatment dose was 43.3 mg (standard deviation, 18.1) and duration was 19.5 weeks (standard deviation, 10.5). Twelve patients were judged to be responders, as defined by a score of 1 or 2 on the CGI-GI. Differences between baseline and the end of the trial period were observed in the following CPRS subscales: Conduct, hyperactivity, inattention, and learning. No differences were noted in the anxiety and psychosomatic subscales. One patient discontinued atomoxetine because of severe mood swings. Atomoxetine may be beneficial for treating secondary symptoms of PDD, and prospective open-label or double-blind, placebo-controlled studies are needed to assess its efficacy and safety. 相似文献
50.