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   18746篇
  免费   1061篇
  国内免费   150篇
耳鼻咽喉   153篇
儿科学   373篇
妇产科学   277篇
基础医学   2339篇
口腔科学   564篇
临床医学   1923篇
内科学   4049篇
皮肤病学   383篇
神经病学   2342篇
特种医学   1276篇
外科学   2868篇
综合类   95篇
一般理论   7篇
预防医学   616篇
眼科学   406篇
药学   979篇
中国医学   13篇
肿瘤学   1294篇
  2024年   14篇
  2023年   155篇
  2022年   318篇
  2021年   539篇
  2020年   348篇
  2019年   409篇
  2018年   498篇
  2017年   440篇
  2016年   568篇
  2015年   635篇
  2014年   792篇
  2013年   913篇
  2012年   1443篇
  2011年   1437篇
  2010年   949篇
  2009年   866篇
  2008年   1295篇
  2007年   1405篇
  2006年   1178篇
  2005年   1197篇
  2004年   1134篇
  2003年   1047篇
  2002年   938篇
  2001年   159篇
  2000年   124篇
  1999年   166篇
  1998年   165篇
  1997年   128篇
  1996年   104篇
  1995年   71篇
  1994年   65篇
  1993年   65篇
  1992年   47篇
  1991年   37篇
  1990年   22篇
  1989年   33篇
  1988年   36篇
  1987年   19篇
  1986年   21篇
  1985年   17篇
  1984年   16篇
  1983年   18篇
  1982年   14篇
  1981年   8篇
  1980年   11篇
  1979年   10篇
  1978年   17篇
  1977年   13篇
  1974年   7篇
  1972年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Posttransplant lymphoproliferative disorder (PTLD) is a serious complication of solid organ transplantation (SOT). Most PTLD cases are associated with Epstein–Barr virus (EBV) infection. The role of antiviral prophylaxis or rituximab therapy for prevention of PTLD in SOT recipients is controversial. In a nationwide cohort, we assessed the incidence, presentation, and outcome of histologically proven PTLD. We included 4765 patients with a follow-up duration of 23 807 person-years (py). Fifty-seven PTLD cases were identified; 39 (68%) were EBV positive (EBV+ PTLD). Incidence rates for EBV+ PTLD at 1, 2, and 3 years posttransplant were 3.51, 2.24, and 1.75/1000 py and 0.44, 0.25, and 0.29/1000 py for EBV− PTLD. We did not find an effect of antiviral prophylaxis on early and late EBV+ PTLD occurrence (early EBV+ PTLD: SHR 0.535 [95% CI 0.199–1.436], p = .264; late EBV+ PTLD: SHR 2.213, [95% CI 0.751–6.521], p = .150). However, none of the patients (0/191) who received a rituximab-containing induction treatment experienced PTLD, but 57 of 4574 patients without rituximab induction developed PTLD. In an adjusted restricted mean survival time model, PTLD-free survival was significantly longer (0.104 years [95% CI 0.077–0.131]) in patients receiving rituximab as induction treatment. This study provides novel data on the association of rituximab induction and reduced risk for PTLD.  相似文献   
83.
Recent studies showed that the COVID‐19 pandemic caused collateral damage in health care in terms of reduced hospital submissions or postponed treatment of other acute or chronic ill patients. An anonymous survey was sent out by mail to patients with chronic wounds in order to evaluate the impact of the pandemic on wound care. Sixty‐three patients returned the survey. In 14%, diagnostic workup or hospitalisation was cancelled or postponed. Thirty‐six percent could not seek consultation by their primary care physician as usual. The use of public transport or long travel time was not related to limited access to medical service (P = .583). In ambulatory care, there was neither a significant difference in the frequency of changing wound dressings (P = .67), nor in the person, who performed wound care (P = .39). There were no significant changes in wound‐specific quality of life (P = .505). No patient used telemedicine in order to avoid face‐to‐face contact or anticipate to pandemic‐related restrictions. The COVID‐19 pandemic impaired access to clinical management of chronic wounds in Germany. It had no significant impact on ambulatory care or wound‐related quality of life. Telemedicine still plays a negligible role in wound care.  相似文献   
84.
85.
86.
Journal of Public Health - Media reporting can influence the perception and development of attitudes through the frequency and the way certain topics are presented. The German Medical Journal...  相似文献   
87.
Summary This review paper is concerned with the topic of mortality differences by socio-economic group in Switzerland. After a short introduction to the topic and the pitfalls associated with it, the paper reviews work done in the course of a ten year programme investigating socio-economic mortality differentials in Switzerland. This programme was carried out by a working group at the Department of Social and Preventive Medicine of the University of Berne. The paper reviews methodological difficulties and pitfalls and relates the Swiss results to findings from other countries including England and Wales and Sweden. The disadvantages of socially isolated groups such as children of single women are shown. The relatively high mortality of groups under economic pressure, such as skilled manual workers in Switzerland, is demonstrated. The Swiss situation is interesting in that skilled manual workers have a higher mortality than the unskilled and semi-skilled groups. It is concluded that this is not an artifact but may be due to the fact that only Swiss workers were investigated and that Switzerland has a large proportion of foreign workers, especially in the less skilled groups. In addition, some results of an investigation of cancer mortality by occupation are reported too. Apart from some occupation-specific findings, there are some interesting cross-references to socio-economic differential mortality.
Sozio-ökonomische Sterblichkeitsunterschiede in der Schweiz
Zusammenfassung Nach einer kurzen Einführung in das Thema Unterschiede in der Sterblichkeit nach sozioökonomischen Gruppen befasst sich diese Übersichtsarbeit mit einem Forschungsprogramm am Institut für Sozial- und Präventivmedizin der Universität Bern, in dem eine Arbeitsgruppe dieses Problem seit 10 Jahren von verschiedenen Seiten umfassend angegangen hat. Neben methodologischen Überlegungen (Datenqualität, Verzerrungsmöglichkeiten) wird vor allem auf die ungünstige Lage von sozial Benachteiligten, wie den Kindern alleinerziehender Mütter sowie von ökonomisch unter Druck stehender Gruppen, wie den manuellen Arbeitern, hingewiesen. Nebst Untersuchungen nach sozio-ökonomischen Gruppen werden auch Ergebnisse zur Krebssterblichkeit nach Berufen vorgestellt. Es ergeben sich hier neue Erkenntnisse auf dem berufsspezifischen Gebiet und Quervergleiche zu den Untersuchungen über sozio-ökonomische Sterblichkeitsunterschiede.

Differences socio-économiques de la mortalité en Suisse
Résumé Après une courte introduction sur les différences de mortalité entre les différentes groupes socioéconomiques ce travail prèsente un programme de recherche de l'Institut de médecine sociale et préventive de l'Université de Berne, un programme dans lequel un groupe de travail a étudié ce problème. En dehors de réflexions méthodologiques (qualité des données, possibilités de biais) l'accent est surtout mis sur la mauvaise situation de personnes socialement désavantagées, comme les enfants de mères seules et de groupes sous pression de la situation économique, comme les travailleurs manuels. Avec les études par groupes socio-économiques les résultats sur la mortalité par le cancer de différentes professions sont présentés. Il en résulte de nouvelles connaissances sur le plan professionnel et des comparaisons transversales avec les études sur les différences socio-économiques de mortalité.


Paper presented at a symposium on The Public Health Perspective of Social and Preventive Medicine, in celebration of the 20th anniversary of the Department of Social and Preventive Medicine, University of Berne, 25 June 1992 in Berne.  相似文献   
88.
The pathophysiology of spondylotic cervical myeolopathy is still a matter of discussion. This paper presents a series of 126 patients operated on using a ventral approach. In 47% of the patients only a spondylotic narrowing of the spinal canal was present and in 35% an additional disc herniation was found. In 13% of the cases however a soft disc without spondylotic spures was found and in 5% a dislocation of vertebral bodies. We found a marked male preponderance of 77%, mean age was 51.6 years, ranging from 25–50 years. Most patients were operated on at the levels of C4/5 and C5/6. Observation time covered a period of 3–10 years. The outcome was rated relatively to the preoperative degree of disablement using a questionnaire for the patients and their family doctors. We found a marked difference in the answers, especially in rating deterioration, which was stated by patients in 34%, by physicians only in 12%. Another finding was the time-related out-come. We found best results with 75% improvement and 5% deterioration between 3–6 months postoperatively, with increasing time the results decreased to 33% improvement, 33% identical statys and in 33% a deterioration related to the preoperative status must be noted.  相似文献   
89.
Pharmacokinetics and bioavailability of benperidol were determined in 13 schizophrenic patients after acute administration of 6 mg benperidol as an intravenous (i.v.) bolus injection, orally as liquid, and orally as tablets using a partially randomized cross-over design. Drug plasma levels were determined by high performance liquid chromatography with electrochemical detection and subjected to model independent pharmacokinetic analyses. After i.v. dosing the geometric means (mean-g) were 3.2 min for the distribution half-life, 5.80 h for the elimination half-life (t 1/2), 4.21 l/kg for the distribution volume, 7.50 h for the mean residence time (MRT), and 0.50 l/(h*kg) for the clearance. After oral administration as liquid and as tablet mean-g data for the time lag until the first appearance of measurable plasma concentrations were 0.33 and 1.1 h, mean-g t 1/2 values were 5.5 and 4.7 h, respectively, mean-g t max data were 1.0 h and 2.7 h, mean-g MRT values were 8.44 and 8.84 h, and mean-g C max maxvalues were 10.2 and 7.3 ng/ml. Differences between liquid and tablet administration were statistically significant for time lag,t max, andC max. Mean-g absolute bioavailabilities were computed as 48.6% after liquid and 40.2% after tablet administration respectively. All parameters studied exhibited large intersubject variation. The plasma concentrations of the presumed metabolite reduced benperidol were found to be very low.  相似文献   
90.
An early common element during anterior-posterior axis formation amongst amniotes is the primitive streak, running longitudinally in the two-layered embryonic disc. In mammals the primordium of this transient structure is the first definite morphological sign of the anterior-posterior axis, while in avian embryos the axis is visible and apparently defined earlier. Here we scrutinize suggestions that in mammals also there are earlier signs of axis formation by using correlative low and high-resolution light microscopy on tissues from rabbit embryos at 6.3 and 6.5 days post-conception, i.e. immediately before and after primitive streak formation. A series of semithin sections were cut from resin-embedded embryonic discs that had been photographed previously at low power. In embryos at 6.5-days post-conception the primitive streak is as long as up to half the diameter of the embryonic disc, extending anteriorly from a thickening, here called the posterior node, at the posterior margin, which contains the first mesoderm cells ingressing from the epiblast. On both sides of the primitive streak there is a triangular area that appears light in surface views of fixed embryos and correlates with stretches of low-columnar simple epithelium in an otherwise high-columnar pseudostratified epiblast. Within the anterior margin, which has a sharper contour than the rest of the circumference of the embryonic disc, there is a narrow, crescent-shaped dark zone caused by increased cellular height and number in both epiblast and hypoblast. These characteristics of the anterior margin are also found at 6.3 days post-conception, at which stage there is no sign of a primitive streak or a posterior node. The posterior margin, in contrast, is ill-defined in these earlier embryos, or there is a light crescent within the posterior margin, which has the same histological characteristics as the bilateral posterior triangular areas of primitive streak stages. Because the anterior differentiation occurs prior to primitive streak formation and is a sign of both the anterior-posterior and the transverse axes of the embryonic disc, and because some of its histological characteristics are found in primate and human embryos, we propose to name this structure the anterior marginal crescent and to add it to the list of transient structures that gradually establish the principal body axes in mammals. The anterior manifestation of body axes in mammals is thus essentially different from axis development in the avian embryo, where differentiation of these axes is first manifest at the posterior margin.Supported by the Deutsche Forschungsgemeinschaft (Vi 151/1-1); part of the results were presented at the First Joint Meeting of the Anatomical Society of Great Britain and Ireland and of the Anatomische Gesellschaft, Southampton, December 1994, and will be published in abstract form (J Anat, in press)  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