全文获取类型
收费全文 | 8270篇 |
免费 | 687篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 94篇 |
儿科学 | 315篇 |
妇产科学 | 108篇 |
基础医学 | 1044篇 |
口腔科学 | 107篇 |
临床医学 | 930篇 |
内科学 | 1491篇 |
皮肤病学 | 75篇 |
神经病学 | 688篇 |
特种医学 | 561篇 |
外科学 | 1111篇 |
综合类 | 249篇 |
现状与发展 | 1篇 |
一般理论 | 3篇 |
预防医学 | 848篇 |
眼科学 | 179篇 |
药学 | 680篇 |
中国医学 | 41篇 |
肿瘤学 | 451篇 |
出版年
2023年 | 36篇 |
2022年 | 44篇 |
2021年 | 110篇 |
2020年 | 76篇 |
2019年 | 112篇 |
2018年 | 128篇 |
2017年 | 111篇 |
2016年 | 96篇 |
2015年 | 138篇 |
2014年 | 215篇 |
2013年 | 302篇 |
2012年 | 399篇 |
2011年 | 418篇 |
2010年 | 287篇 |
2009年 | 276篇 |
2008年 | 400篇 |
2007年 | 449篇 |
2006年 | 365篇 |
2005年 | 350篇 |
2004年 | 345篇 |
2003年 | 308篇 |
2002年 | 316篇 |
2001年 | 270篇 |
2000年 | 248篇 |
1999年 | 216篇 |
1998年 | 169篇 |
1997年 | 121篇 |
1996年 | 139篇 |
1995年 | 134篇 |
1994年 | 99篇 |
1993年 | 96篇 |
1992年 | 181篇 |
1991年 | 156篇 |
1990年 | 141篇 |
1989年 | 144篇 |
1988年 | 135篇 |
1987年 | 135篇 |
1986年 | 106篇 |
1985年 | 128篇 |
1984年 | 114篇 |
1983年 | 92篇 |
1982年 | 61篇 |
1981年 | 71篇 |
1980年 | 57篇 |
1979年 | 80篇 |
1978年 | 58篇 |
1977年 | 59篇 |
1976年 | 35篇 |
1974年 | 46篇 |
1973年 | 34篇 |
排序方式: 共有8976条查询结果,搜索用时 0 毫秒
91.
92.
OBJECTIVES: To determine the spectrum of N and G genotypes of respiratory syncytial virus (RSV) causing respiratory tract infection and whether particular genotypes are associated with severity of infection. PATIENTS AND METHODS: Nasopharyngeal aspirates (NPAs) were obtained from 114 infants with acute respiratory tract infection due to RSV over two seasons. Viral mRNA was extracted from NPAs or cultured virus, reverse transcribed, and the cDNA amplified by the polymerase chain reaction using primers directed to parts of the N and G gene respectively. Amplicons were separately digested with four different restriction endonucleases for each gene. The fragments were separated by agarose gel, electrophoresis, and the electrophoretic patterns used to assign the various genotypes. Disease severity was assessed as very mild (upper respiratory tract signs only), mild (coryza and signs of lower respiratory tract infection), moderate (requiring nasogastric or intravenous fluids), and severe (requiring oxygen or ventilation). RESULTS: Five of the six known N genotypes were detected, but NP4 and NP2 were found most frequently. There was no association between N genotype and disease severity. Six G (SHL) genotypes were detected. Significantly (p = 0.04) more of the infants infected with the SHL2 genotype had severe or moderate disease. CONCLUSIONS: During the seasonal peaks of RSV respiratory tract infection at least 10 different RSV genotypes cocirculated. While there is no association between N genotypes and disease severity, infection with the SHL2 G genotype appears to result in moderate to severe disease. 相似文献
93.
94.
Chlamydia trachomatis infection in prelabour amniorrhexis 总被引:2,自引:0,他引:2
Y. Ville Senior Lecturer S. G Carroll Senior Registrar P. Watts Professor M. Ward Professor K. H. Nicolaides Professor 《BJOG : an international journal of obstetrics and gynaecology》1997,104(9):1091-1093
The prevalence of Chlamydia trachomatis in the lower genital tract and amniotic fluid of women with preterm prelabour amniorrhexis was assessed by DNA amplification for C. trachomatis performed in cervical swabs and amniotic fluid obtained by amniocentesis. C. trachomatis was present in the cervix of 20 (23%) of the cases and in six (30%) of those the organism was also present in the amniotic fluid. There was no association with other pathogens in the lower genital tract or amniotic fluid. The presence of C. trachomatis was not associated with a significant decrease in the amniorrhexis to delivery interval or with an increase in perinatal mortality or morbidity. 相似文献
95.
96.
97.
98.
Koppie TM Grossfeld GD Miller D Yu J Stier D Broering JM Lubeck D Henning JM Flanders SC Carroll PR 《The Journal of urology》2000,164(1):81-88
PURPOSE: We determined the demographic and clinical profile of men who elect surveillance as the initial management of prostate cancer as well as the incidence and predictors of secondary treatment of these patients. MATERIALS AND METHODS: The Cancer of the Prostate Strategic Urological Research Endeavor (CaPSURE) is a national disease registry of patients with various stages and treatments of prostate cancer. Using this database of 4,458 men we identified 329 (8.2%) who elected surveillance as the initial management of prostate cancer. Patients choosing watchful waiting were compared to other CaPSURE participants using the chi-square test. The likelihood of treatment initiation in the watchful waiting group was calculated using the Kaplan-Meier method. After adjusting for patient age, race, prostate specific antigen (PSA) at diagnosis, clinical T stage and total Gleason score the Cox proportional hazards regression model was used to determine significant predictors of treatment initiation. RESULTS: Compared with others in the database, patients on watchful waiting were more likely to be 75 years old or older (51% versus 16%, p <0.001), white (93% versus 85%, p <0.001), and have lower serum PSA (p <0.001), organ confined disease (97% versus 88%, p <0.001) and a total Gleason score of 7 or less (97% versus 88%, p <0.001). In the watchful waiting group there was a 52% likelihood of treatment initiation within 5 years of the diagnosis. Significant predictors of secondary treatment were age younger than 65 years and elevated serum PSA at diagnosis. Neither race, extraprostatic stage cT3 disease nor higher total Gleason score was a significant predictor of treatment. CONCLUSIONS: Men who elect initial watchful waiting for prostate cancer tend to be older, have lower serum PSA and more favorable disease characteristics than those who seek treatment. PSA at diagnosis is the dominant factor for predicting secondary treatment. 相似文献
99.
Oh BR Sasaki M Perinchery G Ryu SB Park YI Carroll P Dahiya R 《The Journal of urology》2000,163(5):1584-1587
PURPOSE: Tumor necrosis factor-alpha (TNF-alpha) is involved in oncogenesis of several cancers. The purpose of this study was to investigate whether genotype changes of TNF-alpha promoter regions (-238, -308) and at the 488 region are associated with human prostate cancer. MATERIALS AND METHODS: The DNA from 73 cases of human prostate cancer was analyzed by allele-specific polymerase chain reaction to characterize the genotype changes of three regions of the TNF-alpha gene in prostate cancer patients. We also determined the genotype frequency in these patients. The relative risk of variant genotype was calculated by comparing with our previous data from healthy controls. RESULTS: Genetic changes were detected in 15.1% (11/73) of prostate cancer samples at 488 region of TNF-alpha. Seventy-three percent (53/73) of the patients showed genotype GA at -308 region of TNF-alpha. Genotype GA at 488 region in TNF-alpha was observed in 73% (53/73) of the cancer and 71% (52/73) of the normal tissue. The relative risks of incidence for prostate cancer was 14-fold higher in people with genotype GA at -308 region of TNF-alpha. The relative incidence for prostate cancer was a 17-fold higher in-patient with genotype GA at 488 region of TNF-alpha. Genotype GA at -308 of TNF-alpha was related to higher clinical tumor stage of prostate cancer than genotype G (p <0.05). CONCLUSIONS: The present study demonstrates, for the first time, that the genotype changes in -308 and 488 regions of TNF-alpha are associated with prostate cancer. 相似文献
100.
W D Carroll W Lenney F Child R C Strange P W Jones M K Whyte R A Primhak A A Fryer 《Archives of disease in childhood》2006,91(5):405-409
BACKGROUND: The relationship between asthma severity and atopy is complex. Many studies have failed to show significant relationships between clinical severity or lung function and markers of atopic sensitisation. AIM: To determine whether increasing asthma severity is related to atopic sensitisation in a population of children with asthma. METHODS: A total of 400 children (7-18 years) with asthma were recruited as part of a multicentre study of the genetics of asthma. Detailed phenotypic data were collected on all participants. Associations between measures of asthma severity and atopic sensitisation were sought using multilevel models allowing variation at the individual and family level. RESULTS: Children recruited to the study had a range of asthma severities, with just over a third having mild persistent asthma. The logarithm of total serum IgE was associated with increased asthma severity score, decreased FEV1, increased airways obstruction, risk of hospital admission, and inhaled steroid use. Increasing skin prick test reactivity to a panel of seven aeroallergens was associated with increased risk of hospital admission, use of an inhaled steroid, and airways obstruction. The results remained highly significant after corrections for age, gender, and birth order. CONCLUSIONS: In children with asthma, increasing atopy is associated with increasing asthma severity. However, the relationships between asthma severity and skin prick tests, and asthma severity and total serum IgE values, appear subtly different. 相似文献