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   15060篇
  免费   533篇
  国内免费   28篇
耳鼻咽喉   373篇
儿科学   983篇
妇产科学   724篇
基础医学   1157篇
口腔科学   254篇
临床医学   739篇
内科学   2900篇
皮肤病学   456篇
神经病学   579篇
特种医学   698篇
外科学   3658篇
综合类   278篇
一般理论   2篇
预防医学   521篇
眼科学   819篇
药学   446篇
中国医学   22篇
肿瘤学   1012篇
  2023年   70篇
  2022年   147篇
  2021年   271篇
  2020年   139篇
  2019年   190篇
  2018年   289篇
  2017年   200篇
  2016年   261篇
  2015年   709篇
  2014年   867篇
  2013年   913篇
  2012年   1079篇
  2011年   1044篇
  2010年   925篇
  2009年   801篇
  2008年   998篇
  2007年   963篇
  2006年   897篇
  2005年   748篇
  2004年   548篇
  2003年   333篇
  2002年   251篇
  2001年   230篇
  2000年   226篇
  1999年   221篇
  1998年   111篇
  1997年   101篇
  1996年   85篇
  1995年   67篇
  1994年   57篇
  1993年   62篇
  1992年   110篇
  1991年   116篇
  1990年   87篇
  1989年   88篇
  1988年   89篇
  1987年   87篇
  1986年   94篇
  1985年   112篇
  1984年   67篇
  1983年   84篇
  1982年   66篇
  1981年   62篇
  1980年   56篇
  1979年   101篇
  1978年   50篇
  1977年   57篇
  1976年   50篇
  1973年   55篇
  1972年   50篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
62.
Studies of associations between perioperative blood transfusions and later recurrence of solid tumors have yielded conflicting results. A previous analysis of transfused patients suggested that recurrence was associated with transfusion of whole blood as opposed to red blood cell concentrates. Additional analyses were performed on patients with cancers of the colon, rectum, cervix, and prostate to determine if patients receiving whole blood, red blood cells only, or no transfusions had differing outcomes. Patients receiving 1 unit or more of whole blood had uniformly poor outcomes compared with nontransfused patients (p less than 0.001). In contrast, patients receiving only red blood cells had progressively worse recurrence and death rates with increasing numbers of transfusion, suggesting the presence of a dose-effect relationship. Employing multivariate techniques, blood transfusion of less than or equal to 3 units that included any whole blood were independently and significantly associated with earlier recurrence (p = 0.003) and death due to cancer (p = 0.02). Transfusions of less than or equal to 3 units of blood comprised solely of red blood cell concentrates were associated with no greater risk of recurrence than that seen in patients receiving no transfusion (p = 0.50). These results provide a potential explanation for the disparate results reported in studies of blood transfusion and cancer outcome. The marked difference in outcome seen between patients receiving a few units of red blood cells and comparable patients receiving even one unit of whole blood are consistent with the hypothesis that transfusion of stored blood plasma causes earlier tumor recurrence in some instances. Strategies for reducing these risks might include avoidance of whole blood transfusions when only 1-3 units are required, more conservative transfusion practice, use of autologous blood transfusions, and perhaps, use of red blood cells washed free of plasma and white cell debris. Clinical trials to test these hypotheses are urgently needed.  相似文献   
63.
Hip arthroplasty is a common orthopaedic procedure with proven long-term success and reliable results. A wide range of associated conditions may affect the outcome of the arthroplasty and the surgeon has to keep these in mind when planning the surgery. In this article, such situations are discussed and recommendations are drawn from the evidence available in literature.  相似文献   
64.
A 14-year-old male presented with abdominal pain, diarrhoea and a sensation of something prolapsing through the anus during defecation, and was found to have diffuse colonic polyposis. There was no evidence of mucocutaneous hyperpigmentation and family history was negative, suggesting a diagnosis of non-familial juvenile polyposis. Histological analysis of multiple endoscopic biopsies showed features typical of juvenile or retention type (hamartomatous) lesions: dilated cystic glands lined by mucocus-secreting epithelium and prominent, inflamed and congested lamina propria. However, admixed with these features, focal areas of atypical adenomatous changes were recognized. Even the intervening normal-looking colonic mucosa showed some dysplastic changes. These findings indicate that hamartomatous and atypical adenomatous epithelial changes can co exist in non-familial juvenile polyposis and the latter may confer a risk of malignant transformation in this otherwise non-neoplastic disease.  相似文献   
65.
66.
The standard surgical protocol presented, with resection of the bone that has not healed. stable osteosynthesis with locking plates, and autologous bone graft augmentation, is an established and successful method of treating atrophic nonunion of the distal humerus. Bone healing was observed in all patients, and a single surgical operation was sufficient. In addition, elbow joint arthrolysis was performed to resect joint fibrosis and ossification and release tissue contractures. With this combined approach bony healing and improvement in range of motion and function of the elbow joint were achieved.  相似文献   
67.
Zusammenfassung Die neurodegenerativen Erkrankungen bestehen aus einer Gruppe heterogener, progredient verlaufender Erkrankungen unterschiedlicher Ätiologie, die ein oder mehrere Systeme beeinträchtigen. Sie treten überwiegend im höheren Lebensalter auf, in dem sich zusätzlich sowohl die Art wie auch das Ausmaß des Schlafes ändern. Die neurodegenerativen Prozesse verursachen strukturelle Veränderungen der Schlaf-Wach-Generatoren im Hirnstamm, die Schlafstörungen wie Tagesschläfrigkeit, Insomnie, nächtliche bewegungs- und schlafbezogene Atmungsstörungen sowie Störungen des zirkadianen Schlaf-Wach-Rhythmus zur Folge haben können. Bei manchen neurodegenerativen Erkrankungen sind im Vorfeld der Krankheitsmanifestation auftretende Schlafstörungen bereits Krankheitsprädiktoren. Polysomnographisch finden sich Schlaffragmentierung, tonische oder phasische Beinbewegungen, Störungen der Atemmuskulatur, verminderter Tiefschlaf, Abwesenheit von REM-Schlaf oder REM-Schlaf ohne Muskelatonie, vermehrte Arousal- und Weckreaktionen, epileptiforme EEG-Aktivität oder schlafbezogene Atmungsstörungen. Sehr häufig sind REM-Schlaf-Verhaltensstörungen assoziiert mit neurodegenerativen Erkrankungen. In dieser Übersichtsarbeit werden Symptomatik, Pathophysiologie und polysomnographische Befunde von Schlafstörungen häufiger neurodegenerativer Erkrankungen vorgestellt.  相似文献   
68.
The case is described of a patient with scleromyxoedema with features typical of systemic sclerosis. The features were so characteristic that the disease was misdiagnosed as systemic sclerosis. A brief review of the association of the two diseases is given.  相似文献   
69.
Summary The debrisoquine/sparteine-type polymorphism of drug oxidation and the polymorphism for acetylation are two common inherited variations in human drug metabolism. The phenotypes for hydroxylation and acetylation can be predicted be newly developed methods based on mutation-specific amplification of DNA by the polymerase chain reaction (PCR), which also allow for identification of heterozygous carriers of one mutant allele.In the present study, the results of genotyping of 81 healthy European volunteers were compared with the phenotype obtained by the classical biochemical approach using debrisoquine and caffeine as probe drugs.Genotyping correctly predicted all 73 extensive metabolisers (EMs) and 6 out of 8 poor metabolisers (PMs) of debrisoquine. All 48 rapid acetylators and 33 of 35 slow acetylators were predicted.Overall, the DNA analysis result matched the in vivo phenotype in 97.5 % of individuals.  相似文献   
70.
The prognostic significance of the size of mastoid air cell system in the results of myringoplasty has been a matter of debate. Fifty ears with dry central perforation following C.S.O.M. were investigated. The size of mastoid air cell system was determined with planimetry of the X-ray picture and eustachian tube function was assessed using flourescein dye and nasal endoscopy. Myringoplasty was performed in all the 50 ears and postoperative results in terms of graft take up and hearing gain were assessed. The correlation between the size of mastoid air cell system, results of myringoplasty and tubal function has been discussed. The results show no correlation between the size of mastoid air cell system, postoperative results of myringoplasty and eustachian tube function.  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