全文获取类型
收费全文 | 7546篇 |
免费 | 688篇 |
国内免费 | 426篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 242篇 |
妇产科学 | 64篇 |
基础医学 | 845篇 |
口腔科学 | 137篇 |
临床医学 | 941篇 |
内科学 | 1230篇 |
皮肤病学 | 112篇 |
神经病学 | 320篇 |
特种医学 | 615篇 |
外国民族医学 | 2篇 |
外科学 | 577篇 |
综合类 | 1148篇 |
预防医学 | 504篇 |
眼科学 | 176篇 |
药学 | 859篇 |
5篇 | |
中国医学 | 367篇 |
肿瘤学 | 493篇 |
出版年
2024年 | 20篇 |
2023年 | 101篇 |
2022年 | 214篇 |
2021年 | 355篇 |
2020年 | 247篇 |
2019年 | 219篇 |
2018年 | 231篇 |
2017年 | 205篇 |
2016年 | 199篇 |
2015年 | 317篇 |
2014年 | 372篇 |
2013年 | 381篇 |
2012年 | 505篇 |
2011年 | 519篇 |
2010年 | 462篇 |
2009年 | 399篇 |
2008年 | 415篇 |
2007年 | 414篇 |
2006年 | 329篇 |
2005年 | 295篇 |
2004年 | 199篇 |
2003年 | 168篇 |
2002年 | 164篇 |
2001年 | 127篇 |
2000年 | 120篇 |
1999年 | 112篇 |
1998年 | 183篇 |
1997年 | 203篇 |
1996年 | 174篇 |
1995年 | 139篇 |
1994年 | 142篇 |
1993年 | 118篇 |
1992年 | 50篇 |
1991年 | 49篇 |
1990年 | 49篇 |
1989年 | 64篇 |
1988年 | 53篇 |
1987年 | 46篇 |
1986年 | 60篇 |
1985年 | 49篇 |
1984年 | 27篇 |
1983年 | 15篇 |
1982年 | 24篇 |
1981年 | 30篇 |
1980年 | 25篇 |
1979年 | 4篇 |
1978年 | 8篇 |
1977年 | 18篇 |
1976年 | 25篇 |
1975年 | 14篇 |
排序方式: 共有8660条查询结果,搜索用时 31 毫秒
61.
Incidence and determinants of moderate COPD (GOLD II) in male smokers aged 40–65 years: 5-year follow up
下载免费PDF全文
![点击此处可从《The British journal of general practice》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Roeland MM Geijer Alfred PE Sachs Theo JM Verheij Philippe L Salom Jan-Willem J Lammers Arno W Hoes 《The British journal of general practice》2006,56(530):656-661
BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a major health problem with an estimated prevalence of 10-15% among smokers. The incidence of moderate COPD, as defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD), is largely unknown. AIM: To determine the cumulative incidence of moderate COPD (forced expiratory volume in 1 second/forced vital capacity ratio [FEV1/FVC] <0.7 and FEV1 <80% predicted) and its association with patient characteristics in a cohort of male smokers. DESIGN: Prospective cohort study. SETTING: The city of IJsselstein, a small town in the Netherlands. METHOD: Smokers aged 40-65 years who were registered with local GPs, participated in a study to identify undetected COPD. Baseline measurements were taken in 1998 of 399 smokers with normal spirometry (n = 292) or mild COPD (FEV1/FVC <0.7 and FEV1 >or=80% predicted, n = 107) and follow-up measurements were conducted in 2003. RESULTS: After a mean follow-up of 5.2 years, 33 participants developed moderate COPD (GOLD II). This showed an estimated cumulative incidence of 8.3% (95% CI = 5.8 to 11.4) and a mean annual incidence of 1.6%. No participant developed severe airflow obstruction. The risk of developing moderate COPD in smokers with baseline mild COPD (GOLD I) was five times higher than in those with baseline normal spirometry (one in five versus one in 25). CONCLUSIONS: In a cohort of middle-aged male smokers, the estimated cumulative incidence of moderate COPD (GOLD II) over 5 years was relatively high (8.3%). Age, childhood smoking, cough, and one or more GP contacts for lower respiratory tract problems were independently associated with incident moderate COPD. 相似文献
62.
63.
64.
Aneuploidy induction by water extract from Tripterygium hypoglaucum (Level) Hutch in mouse bone marrow cells 总被引:2,自引:1,他引:2
Hie aneuploidy-inducing activity of a Chinese medicinal herb,Tripterygium hypoglaucum (level) Hutch (THH), was investigatedby means of three cytogenetic end-points, i.e. C-mitotic (CM)effects, micronuclei (MN) and parallel chromosome structuralaberration (CA) analyses in vivo. The CA analysis was expectedto reflect the origins of MN induced by clastogens or aneugens.The experiments were performed on mouse bone marrow cells. Theanimals were treated with the crude water extracts of THH (singlei.p. injection) in the dose range 120686 mg/kg. Colchicine(COL) was taken as a positive control for its known aneuploidy-inducingeffects. THH showed similar genotoxic effects to COL in CM,MN and CA analyses: positive CM effects were observed accompaniedwith increases of mitotic index and frequencies of CM cellsas well as decreased frequencies of anaphase in all of the THH-treatedgroups. The compound showed a positive MN response in bone marrowpolychromatic erythrocytes but was negative in CA analyses.No sex differences were found in any treated group. The preliminaryresults suggested that THH is an aneuploidy inducer in mousebone marrow cells under the present experimental conditions. 相似文献
65.
M Avellanet RM Mirapeix D Escudero C Riera JM Domenech-Mateu 《Surgical and radiologic anatomy : SRA》1996,18(4):271-273
Summary We present a case with a characteristic magnetic resonance image (MRI) of bilateral open-lipped schizencephaly and atypical clinical presentation. The patient is still alive and in good health in her forties, she has never presented seizures, and although the motor dysfunction is well correlated with cerebral lobe involvement, neurobehavioral dysfunction is not proportional to the MR image of the cerebral malformation.
Un cas inhabituel de schizencéphalie bilatérale
Résumé Nous présentons un cas de schizencéphalie bilatérale ouverte caractérisé par une présentation clinique atypique et une imagerie par résonance magnétique nucléaire caractéristique. La patiente est encore vivante, en bonne santé, à plus de 40 ans, elle n'a jamais présenté de crise comitiale et, bien que les troubles moteurs soient bien corrélés aux altérations cérébrales, les troubles neuro-comportementaux ne sont pas proportionnels aux images IRM de cette malformation cérébrale.相似文献
66.
Kermit Zhang Eleina Cox Samuel Strom Zhuo Luan Xu Alexis Disilvestro Kelly Usrey 《American journal of medical genetics. Part A》2020,182(9):2124-2128
Baraitser‐Winter cerebrofrontofacial syndrome (BWCFF) is a rare autosomal dominant developmental disorder associated with missense mutations in the genes ACTB or ACTG1. The classic presentation of BWCFF is discerned by the combination of unique craniofacial characteristics including ocular coloboma, intellectual disability, and hypertelorism. Congenital contractures and organ malformations are often present, including structural defects in the brain, heart, renal, and musculoskeletal system. However, there is limited documentation regarding its prenatal presentation that may encourage healthcare providers to be aware of this disorder when presented throughout pregnancy. Herein we describe a case of a pregnancy with large cystic hygroma and omphalocele. Whole exome sequencing (WES) was performed and a de novo, heterozygous, likely pathogenic mutation in ACTB was detected, c.1004G>A (p.Arg335His), conferring a diagnosis of BWCFF. 相似文献
67.
为探讨烧伤对大鼠免疫功能的影响及不同免疫调节剂对它的作用,本研究利用烫伤大鼠实验模型,采用溶血分光光度法和微量细胞病变抑制法,在整体条件下分别测定了各组烫伤大鼠伤后第5、10天时脾细胞产生TFN-γ和抗SRTBC抗体的能力。 相似文献
68.
69.
70.
肾阳虚证患者红细胞LPO、SOD和ATP酶活性的变化 总被引:6,自引:0,他引:6
目的 :探讨肾阳虚证患者红细胞LPO、SOD和ATP酶活性的特点及其意义。方法 :观察 19例肾阳虚证患者和 2 1例正常人红细胞LPO、SOD和红细胞膜Na+ K+ ATP酶、Mg2 + ATP酶、Ca2 + ATP酶、Ca2 + Mg2 + ATP酶活性的变化。结果 :与对照组比较 ,肾阳虚证患者红细胞LPO含量升高 (P <0 .0 1) ,红细胞SOD活性降低 (P <0 .0 1) ;红细胞膜Na+ K+ ATP酶活性显著升高 (P <0 .0 1) ,而Mg2 + ATP酶活性变化无显著性差异 ,Ca2 + ATP酶活性升高 (P <0 .0 1) ,Ca2 + Mg2 + ATP酶活性也显著升高 (P <0 .0 1)。结论 :肾阳虚证患者红细胞内脂质过氧化反应增强 ,而抗氧化能力降低 ,红细胞膜Na+ K+ ATP酶、Ca2 + ATP酶和Ca2 + Mg2 + ATP酶活性升高 ;本研究为理解肾阳虚证的病理生理基础提供了初步实验依据 相似文献