首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   28327篇
  免费   2740篇
  国内免费   2254篇
耳鼻咽喉   204篇
儿科学   312篇
妇产科学   314篇
基础医学   3698篇
口腔科学   476篇
临床医学   3878篇
内科学   4574篇
皮肤病学   248篇
神经病学   1447篇
特种医学   1001篇
外国民族医学   21篇
外科学   2935篇
综合类   4453篇
现状与发展   9篇
一般理论   4篇
预防医学   1726篇
眼科学   717篇
药学   2850篇
  31篇
中国医学   1502篇
肿瘤学   2921篇
  2024年   109篇
  2023年   495篇
  2022年   1286篇
  2021年   1642篇
  2020年   1222篇
  2019年   980篇
  2018年   1069篇
  2017年   910篇
  2016年   873篇
  2015年   1372篇
  2014年   1686篇
  2013年   1337篇
  2012年   2008篇
  2011年   2255篇
  2010年   1365篇
  2009年   1075篇
  2008年   1409篇
  2007年   1471篇
  2006年   1394篇
  2005年   1522篇
  2004年   901篇
  2003年   796篇
  2002年   744篇
  2001年   617篇
  2000年   617篇
  1999年   687篇
  1998年   519篇
  1997年   470篇
  1996年   395篇
  1995年   362篇
  1994年   284篇
  1993年   165篇
  1992年   226篇
  1991年   169篇
  1990年   149篇
  1989年   137篇
  1988年   153篇
  1987年   101篇
  1986年   96篇
  1985年   71篇
  1984年   41篇
  1983年   34篇
  1982年   28篇
  1981年   21篇
  1980年   10篇
  1979年   18篇
  1978年   5篇
  1975年   3篇
  1971年   5篇
  1969年   5篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
11.
Summary To investigate the distribution of possible novel mutations from parkin gene in variant subset of patients with Parkinson’s disease (PD) in China and explore whether parkin gene plays an important role in the pathogenesis of PD, 70 patients were divided into early-onset group and late-onset group; 70 healthy subjects were included as controls. Genomic DNA from 70 normal controls and from those of PD patients were extracted from peripheral blood leukocytes by using standard procedures. Mutations of parkin gene (exon 1–12) in all the subjects were screened by PCR-single strand conformation polymorphism (SSCP), and further sequencing was performed in the samples with abnormal SSCP results, in order to confirm the mutation and its location. A new missense mutation Gly284Arg in a patient and 3 abnormal bands in SSCP electrophoresis from samples of another 3 patients were found. All the DNA variants were sourced from the samples of the patients with early-onset PD. It was concluded that Parkin point mutation also partially contributes to the development of early-onset Parkinson’s disease in Chinese. WANG Tao, male, born in 1961, Associate Professor This work was supported by grants from the key program of the special scientific project of Scientific & Technologic Agency of Hubei Province (Serial No. 2001AA308B01) and the Hygienic Research Project of Hygienic Agency of Hubei province (Serial No. WJ 01529).  相似文献   
12.
The paper describes the prenatal ultrasonographic diagnosis of conjoined syncephalus-craniothoraco-omphalopagus twins at 13 weeks' gestation. The mother, after genetic counseling, decided to interrupt the pregnancy. The fetal karyotype, the maternal serum and amniotic fluid alpha-fetoprotein levels were normal. The diagnosis was confirmed by pathologic examination of the fetus after termination of pregnancy.  相似文献   
13.
14.
取32只2~3个月的BALB/C小白鼠,随机分为4组,每组8只,第1组为对照组,其余3个组为实验组,实验组小白鼠左腿皮下注射苯0.3ml(15ml/kg体重).注射后分别于24h,48h,72h脱颈处死。观察中毒前、后末梢血象、骨髓细胞、骨髓细胞构成的变化。结果表明,苯中毒时骨髓变化先于末梢血象的变化,骨髓的病变为造血细胞变性、坏死,大量毛细血管扩张、充血,骨髓细胞构成降低,而且骨髓细胞构成中细胞成分降低早于外周血粒细胞减少。  相似文献   
15.
笔者从事临床医疗工作20余年,自拟解毒消肿散治疗因阳热毒邪蕴蒸肌肤所致的多种外科疾患,屡获捷效,现报道如下。方药组成与使用方法蒲公英30g,紫花地丁30g,玄明粉50g,冰片6g,共研细末调和均匀,贮瓶密封备用。使用时,视肿疡面积大小,取适量药粉,用食醋调成糊状,摊敷在病变部位,厚约0.5~0.8cm,用塑料薄膜覆盖,外用胶布固定。药物干燥时,可再用食醋浸湿。每日换药2~3次。本方具有清热解毒、散瘀消肿、消炎止痛的作用。主治痈、疽、疔、疖、乳痈、痄腮、毒虫咬伤、痔瘘、肛裂、无名肿毒等证,凡红肿热痛属阳证、热证、实证者均可应用,阴证、寒证…  相似文献   
16.
An animal model of chronic tympanic membrane perforation.   总被引:6,自引:0,他引:6  
Previous investigations into the healing and reconstruction of tympanic membrane (TM) perforations have involved animal models with acute TM perforations. A problem with the acute TM perforation model is that most acute TM perforations will heal spontaneously, both in animals and human beings. A second inadequacy of acute perforation models is that they are not analogous to the salient problem in human beings: long-standing TM perforation. The ideal animal model must have a TM perforation that is permanent, well-epithelialized, and free from infection. The perforation must also be subtotal to preserve a rim of membrane for experimental manipulations. In the chinchilla, we have identified a hardy animal with a short, wide ear canal and relatively large tympanic membranes. Thermal myringectomy, followed by medial infolding of TM microflaps, has resulted in permanent, subtotal chronic TM perforations in the chinchilla animal model. Of the 19 chinchillas (38 TMs) perforated, chronic subtotal perforations were created in 32 ears, 6 to 8 weeks after the initial procedure (84% success). Persistent infection or TM regeneration despite reperforation was recorded in 6 ears (16%) failure). This model is currently being used to assess various biomembrane scaffolds impregnated with growth-promoting substances in the regeneration of a physiologically sound TM, initially in our animal model and then in human beings. We envision the development of a biomembrane disc impregnated with biorecombinant growth factors that may provide a simple office technique for the repair of chronic, non-infected TM perforations.  相似文献   
17.
报道辐照氟银猪皮的制备、实验检测(弹性、创面粘附力和透水性测定,含银量测定)组织学检查细菌检测及抑菌试验研究,结果表明:辐照氟银猪皮除延伸度低于未辐照猪皮外,其撕裂强度、创面粘合力和透水性均与未辐照猪皮相似。组织学检查示:辐照氟银猪皮组织结构完整,表皮细胞部分空泡形成。组织细菌检测证明其无菌生长,达到无菌要求。抑菌试验证明对金黄色葡萄球菌、绿脓杆菌、大肠杆菌、变形杆菌、克雷伯氏菌均有极强的抑菌作用  相似文献   
18.
19.
电针改善硬膜外吗啡用于术后镇痛所引起的免疫抑制   总被引:1,自引:1,他引:0  
为观察硬膜外吗啡和电针对术后患者免疫功能的影响,检测自然杀伤细胞(NKcell)活性和PHA诱导白细胞介素2(IL-2)水平在单纯胆囊切除术患者术前和术后第1、3、7天的动态变化情况。结果吗啡组NK活性在术后第1、3、7天抑制,手术组仅在术后第1、3天出现抑制,而抑制率低于同天的吗啡组,电针可拮抗吗啡引起的NK活性抑制加深状况。在术后第1天,手术组和吗啡组IL-2水平均下降,吗啡+电针组无明显变化,术后第7天吗啡+电针组IL-2升高接近正常人水平。表明电针能改善硬膜外吗啡引起的免疫抑制,促进术后机体的恢复。硬膜外吗啡结合电针是值得推荐的术后镇痛方法。  相似文献   
20.
In order to clarify the reasons for the reduced Hb A2 levels in Sardinian delta beta-thalassemia, we characterized, both by cloning and sequence analysis and by direct sequencing of amplified DNA, the delta-globin gene from an individual of Sardinian descent who is a compound heterozygote for the beta zero-thalassemia codon 39 (C-->T) nonsense mutation and the Sardinian delta beta-thalassemia [codon 39(C-->T)/-196(C-->T)A gamma]. The analysis of the delta-globin gene from the delta beta-thalassemia chromosome revealed an entirely normal sequence. The defective function of the delta-globin gene in this determinant is thus likely related to a suppressive effect of the in cis nondeletional high persistence of fetal hemoglobin mutation of the A gamma gene, probably resulting from an increased capability of the relative promoter to interact with the locus control region.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号