全文获取类型
收费全文 | 1262篇 |
免费 | 76篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 20篇 |
妇产科学 | 5篇 |
基础医学 | 154篇 |
口腔科学 | 23篇 |
临床医学 | 137篇 |
内科学 | 231篇 |
皮肤病学 | 20篇 |
神经病学 | 135篇 |
特种医学 | 59篇 |
外科学 | 197篇 |
综合类 | 3篇 |
预防医学 | 197篇 |
眼科学 | 3篇 |
药学 | 75篇 |
肿瘤学 | 46篇 |
出版年
2023年 | 10篇 |
2022年 | 18篇 |
2021年 | 33篇 |
2020年 | 19篇 |
2019年 | 38篇 |
2018年 | 29篇 |
2017年 | 26篇 |
2016年 | 41篇 |
2015年 | 25篇 |
2014年 | 40篇 |
2013年 | 62篇 |
2012年 | 95篇 |
2011年 | 79篇 |
2010年 | 46篇 |
2009年 | 46篇 |
2008年 | 98篇 |
2007年 | 105篇 |
2006年 | 80篇 |
2005年 | 100篇 |
2004年 | 70篇 |
2003年 | 70篇 |
2002年 | 79篇 |
2001年 | 13篇 |
2000年 | 20篇 |
1999年 | 15篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有1342条查询结果,搜索用时 15 毫秒
991.
Kunnas TA Ilveskoski E Niskakangas T Laippala P Kajander OA Mikkelsson J Goebeler S Penttilä A Perola M Nikkari ST Karhunen PJ 《Journal of molecular medicine (Berlin, Germany)》2002,80(9):605-609
Nitric oxide (NO), formed by endothelial constitutive nitric oxide synthase (eNOS) maintains endothelium-dependent vasodilatation and also mediates antithrombotic actions. The eNOS gene harbours a common polymorphism in intron 4 (4a/b), and some clinical studies have suggested an association of the rare a-allele with coronary artery disease (CAD) and myocardial infarction (MI). However, contradictory results have also been reported. We studied associations of eNOS polymorphism with CAD and MI in two prospective autopsy series comprising altogether 700 Caucasian Finnish men, who died suddenly. In ANCOVA, no significant differences in areas of atherosclerotic lesions and coronary stenosis percentages were found between men carrying the a-allele (ba+aa) compared with those homozygous for the b-allele. Subjects with the a-allele had significantly lower risk of MI (odds ratio 0.44, 95% confidence interval 0.25-0.77, P=0.004) compared with those carrying the bb genotype. Men with the a-allele also tended to have coronary thrombosis less often (odds ratio 0.43, 95% confidence interval 0.18-1.01, P=0.055). The eNOS gene 4a/b polymorphism was not associated with the extent of coronary atherosclerosis, but the a-allele of the variant seems to protect to some degree against the development of MI. 相似文献
992.
993.
994.
Infantile pertussis rediscovered in China 总被引:3,自引:0,他引:3
Wang J Yang Y Li J Mertsola J Arvilommi H Shen X He Q 《Emerging infectious diseases》2002,8(8):859-861
Immunization against pertussis was introduced in China in the 1960s. Since the 1970s, no culture-confirmed pertussis cases have been reported in the country. We report six infants with culture-confirmed pertussis, who were initially diagnosed as having other respiratory diseases at Beijing Children's Hospital, Beijing. 相似文献
995.
Kudlacek O Waldhoer M Kassack MU Nickel P Salmi JI Freissmuth M Nanoff C 《Naunyn-Schmiedeberg's archives of pharmacology》2002,365(1):8-16
The interface between receptors and G proteins can be considered as a drug target. Various classes of low molecular weight inhibitors have been identified that block the ability of receptors to interact with G proteins (e.g. peptides, suramin analogues and amphiphilic cations). Here we have tested if there are compounds that differentially affect the interaction of one receptor with two different (related) G protein alpha-subunits. Fusion proteins comprising the human A1-adenosine receptor and Galphai-1 (A1/Galphai-1) or Galphao (A1/Galphao) were expressed in HEK293 cells. Suramin analogues were screened for their ability to differentially affect high affinity binding of the agonist (-) N6-3-[125I](iodo-4-hydroxyphenylisopropyl) adenosine (IHPIA).One compound [NF326 = 8,8'-(carbonylbis-(imino-3,1-phenylenecarbonylimino))bis-(1-naphthol-3,6-disulfonic acid, disodium salt)] was identified that inhibited high affinity agonist binding to the fusion protein A1/Galphai-1 but modestly enhanced binding of IHPIA to A1/Galphao. This action was specific because NF326 did not affect antagonist binding to either fusion protein. In addition, it was unrelated to a difference in affinity of the receptor for the G protein fusion moiety because the stability of ternary complexes formed by IHPIA + A1/Galphai-1 and IHPIA + A1/Galphao) is comparable and because lowering the affinity of the receptor for the G protein (by introducing point mutations at cys351 of Galphai-1) enhanced the uncoupling effect of NF326. Finally, NF326 did not discriminate between a fusion protein comprising the alpha2A-adrenoceptor and Galphai-1 (alpha2A)/Galphai-1) or Galphao-1 (alpha2A)/Galphao-1); binding of the agonist [3H]UK14304 (bromoxidine) to both fusion proteins was inhibited over a comparable concentration range while binding of the antagonist [3H]yohimbine was unaffected.These observations are consistent with the interpretation that the contact sites that are formed between individual receptors and G proteins differ. These differences suffice to allow for selective disruption by G protein inhibitors of different classes. Using NF326 we show that the bulk of the A1-adenosine receptors in human cerebrocortical membranes interacts with Galphao rather than Galphai. 相似文献
996.
Lead-time in prostate cancer screening (Finland) 总被引:2,自引:0,他引:2
Auvinen A Määttänen L Stenman UH Tammela T Rannikko S Aro J Juusela H Hakama M 《Cancer causes & control : CCC》2002,13(3):279-285
Objective: Lead-time in prostate cancer screening was estimated using data from the Finnish randomized, population-based trial. Methods: Lead-time was defined as the duration of follow-up needed to accrue the same expected number of incident prostate cancer cases in the absence of screening as detected in the initial screening round. Expected numbers were calculated using an age-cohort model. Results: Based on findings among 10,000 men screened in 1996–1997 with 292 screen-detected cancers, lead-time was estimated as approximately 5–7 years, depending on the reference rates used. This corresponds to a mean duration of the detectable preclinical phase (DPCP) of 10–14 years, given that the cancers were detected on average at the midpoint of the DPCP. Conclusions: The findings suggest that a screening interval substantially longer than the 2 years generally used for mammography screening is unlikely to cause a substantial loss of sensitivity. A long screening interval is further justified in order to diminish the extent of overdiagnosis, until mortality effects can be evaluated. 相似文献
997.
Ville T. Ponkilainen Mikko Miettinen Henrik Sandelin Jan Lindahl Arja H. Häkkinen Alar Toom Tomi Tillgren Outi Ilves Antti O. Latvala Katri Ahonen Timo Sirola Mika Sampo Olli Väistö Jussi P. Repo 《Foot and Ankle Surgery》2021,27(1):93-100
BackgroundThe 16-item patient-reported Manchester-Oxford Foot Questionnaire (MOXFQ) with subscales of pain, social interactions, and walking/standing has been claimed for strongest scientific evidence in measuring foot and ankle complaints. This study tests the validity of the Finnish MOXFQ for orthopaedic foot and ankle population using the Rasch analysis.MethodsWe translated the MOXFQ into Finnish and used that translation in our study. MOXFQ scores were obtained from 183 patients. Response category distribution, item fit, coverage, targeting, item dependency, ability to measure latent trait (unidimensionality), internal consistency (Cronbach’s alpha), and person separation index (PSI) were analyzed.ResultsFifteen of the items had ordered response categories and/or sufficient fit statistics. The subscales provided coverage and targeting. Some residual correlation was noted. Removing one item in the pain subscale led to a unidimensional structure. Alphas and PSIs ranged between 0.68–0.90 and 0.67–0.92, respectively.ConclusionsDespite some infractions of the Rasch model, the instrument functioned well. The subscales of the MOXFQ are meaningful for assessing patient-reported complaints and outcomes in orthopaedic foot and ankle population. 相似文献
998.
Anu Juslin Anthonin Reilhac Margarita Magadán-Méndez Edisson Albán Jussi Tohka et al. 《Neurosurgical review》1989,12(2):172-172
Announcement
Epilepsy surgery 相似文献999.
1000.
It has been shown in previous studies on sleep electroencephalogram (EEG) that spindles are slower in the beginning of the night fastening towards the end of the night. Corresponding findings have been obtained by spectral analysis. The present study was based on our preliminary observation that slower spindles are found in the middle of the non-rapid eye movement (NREM) sleep episodes as compared with the beginning or the end of the episodes. Eight healthy female and six male subjects were studied. Sleep spindles were visually selected and spindle frequencies calculated for 11 analysis points in each NREM sleep episode. The median spindle frequencies formed a clear U-shape within NREM sleep episodes with an initial decrease and final increase. The decrease was statistically significant within the first four NREM sleep episodes. It is possible that the spindle frequency pattern could be used to reveal variations in sleep depth within sleep stage 2. In animal studies the spindle frequency has been found to be associated to the duration of the hyperpolarization-rebound sequences of the thalamocortical cells. If it is assumed that the same cellular mechanisms are responsible for spindle frequencies in humans then the study of variations in spindle frequency could be used to examine the NREM sleep process in humans. 相似文献