全文获取类型
收费全文 | 245125篇 |
免费 | 5999篇 |
国内免费 | 200篇 |
专业分类
耳鼻咽喉 | 1651篇 |
儿科学 | 8665篇 |
妇产科学 | 4188篇 |
基础医学 | 26151篇 |
口腔科学 | 3030篇 |
临床医学 | 19695篇 |
内科学 | 45572篇 |
皮肤病学 | 1650篇 |
神经病学 | 22992篇 |
特种医学 | 11049篇 |
外国民族医学 | 1篇 |
外科学 | 38652篇 |
综合类 | 3191篇 |
一般理论 | 72篇 |
预防医学 | 24211篇 |
眼科学 | 4434篇 |
药学 | 14295篇 |
1篇 | |
中国医学 | 702篇 |
肿瘤学 | 21122篇 |
出版年
2023年 | 343篇 |
2022年 | 431篇 |
2021年 | 1413篇 |
2020年 | 850篇 |
2019年 | 1383篇 |
2018年 | 23394篇 |
2017年 | 18431篇 |
2016年 | 20666篇 |
2015年 | 2464篇 |
2014年 | 3145篇 |
2013年 | 3955篇 |
2012年 | 12103篇 |
2011年 | 26127篇 |
2010年 | 21596篇 |
2009年 | 14064篇 |
2008年 | 24114篇 |
2007年 | 26740篇 |
2006年 | 5733篇 |
2005年 | 7077篇 |
2004年 | 8078篇 |
2003年 | 8577篇 |
2002年 | 6647篇 |
2001年 | 885篇 |
2000年 | 854篇 |
1999年 | 834篇 |
1998年 | 1110篇 |
1997年 | 959篇 |
1996年 | 731篇 |
1995年 | 708篇 |
1994年 | 587篇 |
1993年 | 526篇 |
1992年 | 412篇 |
1991年 | 409篇 |
1990年 | 399篇 |
1989年 | 355篇 |
1988年 | 333篇 |
1987年 | 278篇 |
1986年 | 276篇 |
1985年 | 296篇 |
1984年 | 344篇 |
1983年 | 358篇 |
1982年 | 420篇 |
1981年 | 379篇 |
1980年 | 392篇 |
1979年 | 219篇 |
1978年 | 260篇 |
1977年 | 203篇 |
1976年 | 148篇 |
1975年 | 109篇 |
1974年 | 133篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
52.
Stephen J Glatt Erik G J?nsson 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2006,(2):149-154
Previously we derived independent estimates of the effect of the dopamine D2 receptor (DRD2) Ser311Cys polymorphism on risk for schizophrenia using fixed- and random-effects meta-analyses. Both analyses identified a significant association between the Cys allele and schizophrenia, but neither included all available data. Furthermore, genotype data were not evaluated in either analysis, thus precluding any determination of the mode of inheritance. The present study was conducted to resolve discrepancies between the existing meta-analyses, and provide more comprehensive and accurate estimates of the nature and magnitude of the influence of the Ser311Cys polymorphism on risk for schizophrenia. All discrepancies between the two sets of previously meta-analyzed studies were identified and resolved to the mutual satisfaction of the authors, and the final dataset was analyzed independently by fixed- and random-effects meta-analyses. A total of 27 samples, comprising 3,707 schizophrenia patients and 5,363 control subjects, were included in the analyses of allelic association, while smaller numbers of studies and subjects were included in each of the genotypic association analyses. A significant effect of the Cys allele was observed under both fixed-effects (odds ratio [OR] = 1.4; P = 0.002) and random-effects (OR = 1.4; P = 0.007) models. Cys/Ser heterozygotes were at elevated risk for schizophrenia when compared to Ser/Ser homozygotes (fixed- and random-effects OR = 1.4, p(s) or= 0.948). There was no evidence of heterogeneity, excessive influence of any single study, or publication bias in any of the analyses, suggesting that the effect of this DRD2 polymorphism on schizophrenia risk is reliable and uniform across populations, and our estimates of its magnitude are robust and accurate. 相似文献
53.
54.
55.
56.
57.
Eric W. Dickson MD Gary V. Doern PhD Leo Trevino PhD Michelle Mazzoni PhD Stephen O. Heard MD 《Academic emergency medicine》2003,10(10):1019-1023
OBJECTIVES: Patients undergoing emergent endotracheal intubation are at increased risk for developing pneumonia. Although numerous strategies have been investigated to reduce ventilator-associated pneumonia (VAP), the incidence of VAP and its associated mortality remains high. This investigation tested the hypothesis that LiquiVent (Alliance Pharmaceutical, San Diego, CA-LV) delivered antibiotics (via spray-dried microspheres-SDM) would improve survival in a rat model of descending gram-negative pneumonia. METHODS: Wistar rats (n = 49) were randomized to receive prophylaxis with 1). nothing (controls); 2). intramuscular (IM) tobramycin, 3). intratracheal LV plus SDM shells (vehicle), 4). intratracheal LV plus SDM shells plus IM tobramycin, or 5). intratracheal LV plus SDM containing 1 mg/kg of tobramycin. All interventions were given 24 hours before a bacterial challenge with 10(8) colony-forming units of intratracheal Klebsiella pneumoniae. Mortality at ten days was the sole outcome measure. Survival in individual groups was compared with controls by Fisher's exact test with Bonferroni correction for multiple comparisons. RESULTS: All animals in the control group died of pneumonia within ten days of bacterial inoculation (0% survival). Prophylaxis with either IM tobramycin or SDM vehicle plus IM tobramycin provided no protection (0% survival). This is in sharp contrast to the cohort receiving pretreatment with tobramycin-containing SDM delivered via LV, in which 60% of the animals survived to study completion (p < 0.05). CONCLUSIONS: Prophylaxis with SDM containing antibiotics delivered in low-dose LV provided significant protection in a rat model of descending gram-negative pneumonia. These data support the hypothesis that perfluorocarbon-delivered intratracheal antimicrobials may be useful in the prevention of VAP. 相似文献
58.
59.
Stephen Kellett Nigel Beail David W. Newman Pat Frankish 《Journal of Applied Research in Intellectual Disabilities》2003,16(2):127-134
Introduction People with intellectual disabilities are now acknowledged to be susceptible to the full range of mental health disorders. This acknowledgement has resulted in the need to develop and evaluate instruments for the assessment and detection of mental health problems. This research evaluates the use of the Brief Symptom Inventory (BSI) with 200 people with mild intellectual disabilities representing community, clinical and forensic populations. Results and conclusions Results illustrate the reliability of the BSI for each of the groups and demonstrates how the Positive Symptom Total (PST) index effectively discriminates between study groups. Case rates for each group are provided. The study illustrates that the BSI could be employed as a brief multitrait assessment instrument and as a treatment outcome measure with people with an intellectual disability. 相似文献
60.