全文获取类型
收费全文 | 1788篇 |
免费 | 94篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 72篇 |
妇产科学 | 79篇 |
基础医学 | 204篇 |
口腔科学 | 33篇 |
临床医学 | 173篇 |
内科学 | 271篇 |
皮肤病学 | 15篇 |
神经病学 | 196篇 |
特种医学 | 96篇 |
外科学 | 323篇 |
综合类 | 12篇 |
预防医学 | 127篇 |
眼科学 | 20篇 |
药学 | 103篇 |
中国医学 | 6篇 |
肿瘤学 | 149篇 |
出版年
2024年 | 6篇 |
2023年 | 25篇 |
2022年 | 22篇 |
2021年 | 50篇 |
2020年 | 52篇 |
2019年 | 66篇 |
2018年 | 49篇 |
2017年 | 43篇 |
2016年 | 51篇 |
2015年 | 56篇 |
2014年 | 61篇 |
2013年 | 86篇 |
2012年 | 114篇 |
2011年 | 117篇 |
2010年 | 59篇 |
2009年 | 43篇 |
2008年 | 93篇 |
2007年 | 84篇 |
2006年 | 62篇 |
2005年 | 62篇 |
2004年 | 71篇 |
2003年 | 65篇 |
2002年 | 51篇 |
2001年 | 40篇 |
2000年 | 32篇 |
1999年 | 41篇 |
1998年 | 18篇 |
1997年 | 10篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 13篇 |
1993年 | 13篇 |
1992年 | 21篇 |
1991年 | 24篇 |
1990年 | 24篇 |
1989年 | 27篇 |
1988年 | 18篇 |
1987年 | 17篇 |
1986年 | 24篇 |
1985年 | 13篇 |
1984年 | 19篇 |
1983年 | 11篇 |
1982年 | 13篇 |
1980年 | 10篇 |
1979年 | 10篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1974年 | 7篇 |
1968年 | 8篇 |
排序方式: 共有1884条查询结果,搜索用时 15 毫秒
1.
2.
Camilla Nyboe Jonas A. Funder Morten H. Smerup Hans Nygaard J. Michael Hasenkam 《European journal of cardio-thoracic surgery》2006,29(6):1008-1013
Objective: Mechanical heart valves can cause thromboembolic complications, possibly due to abnormal flow patterns that produce turbulence downstream of the valve. The objective of this study was to investigate whether three different bileaflet valve designs would exhibit clinically relevant differences in downstream turbulent stresses. Methods: Three bileaflet mechanical heart valves (Medtronic Advantage®, CarboMedics© Orbis™ Universal and St. Jude Medical® Standard) were implanted into 19 female 90 kg pigs. Blood velocity was measured during open chest conditions in the cross sectional area downstream of the valves with 10 MHz ultrasonic probes connected to a modified Alfred® Pulsed Doppler equipment. As a measure of turbulence, Reynolds normal stress (RNS) was calculated at three different cardiac output ranges (3–4, 4.5–5.5, 6–7 L/min). Results: Data from 12 animals were obtained. RNS correlated with increasing cardiac outputs. The highest instantaneous RNS observed in these experiments was 47 N/m2, and the mean RNS taken spatially over the cross sectional area of the aorta during systole was between 3 N/m2 and 15 N/m2. In none of the cardiac output ranges RNS values exceeded the lower critical limit for erythrocyte or thrombocyte damage for any of the valve designs. Conclusions: Reynolds normal stress values were below 100 N/m2 for all three valve designs and the difference in design was not reflected in generation of turbulence. Hence, it is unlikely that any of the valve designs causes flow induced damage to platelets or erythrocytes. 相似文献
3.
Background
January 1, 2002, copayment for outpatient female sterilization in Norwegian public hospitals increased from 33 euros to 750 euros after a revision of the health care system. The aim of the present study was to investigate the effect of the new copayment system on female sterilization epidemiology. 相似文献4.
5.
Madsen Christina Merete Tvede Bisgaard Sara Kjær Primdahl Jette Christensen Jeanette Reffstrup von Bülow Cecilie 《Journal of occupational rehabilitation》2021,31(4):866-885
Journal of Occupational Rehabilitation - Purpose To present an overview of the evidence of the effect of job loss prevention interventions, aiming to improve work ability and decrease absenteeism... 相似文献
6.
Distal rectus femoris surgery in children with cerebral palsy: results of a Delphi consensus project
Robert M. Kay Kristan Pierz James McCarthy H. Kerr Graham Henry Chambers Jon R. Davids Unni Narayanan Tom F. Novacheck Jason Rhodes Erich Rutz Jeffrey Shilt Benjamin J. Shore Matthew Veerkamp M. Wade Shrader Tim Theologis Anja Van Campenhout Thomas Dreher 《Journal of children's orthopaedics》2021,15(3):270
PurposeThe purpose of this study was for an international panel of experts to establish consensus indications for distal rectus femoris surgery in children with cerebral palsy (CP) using a modified Delphi method.MethodsThe panel used a five-level Likert scale to record agreement or disagreement with 33 statements regarding distal rectus femoris surgery. The panel responded to statements regarding general characteristics, clinical indications, computerized gait data, intraoperative techniques and outcome measures. Consensus was defined as at least 80% of responses being in the highest or lowest two of the five Likert ratings, and general agreement as 60% to 79% falling into the highest or lowest two ratings. There was no agreement if neither threshold was reached.ResultsConsensus or general agreement was reached for 17 of 33 statements (52%). There was general consensus that distal rectus femoris surgery is better for stiff knee gait than is proximal rectus femoris release. There was no consensus about whether the results of distal rectus femoris release were comparable to those following distal rectus femoris transfer. Gross Motor Function Classification System (GMFCS) level was an important factor for the panel, with the best outcomes expected in children functioning at GMFCS levels I and II. The panel also reached consensus that they do distal rectus femoris surgery less frequently than earlier in their careers, in large part reflecting the narrowing of indications for this surgery over the last decade.ConclusionThis study can help paediatric orthopaedic surgeons optimize decision-making for, and outcomes of, distal rectus femoris surgery in children with CP.Level of evidenceV 相似文献
7.
8.
Genetic mapping of "Lubag" (X-linked dystonia-parkinsonism) in a Filipino kindred to the pericentromeric region of the X chromosome. 总被引:3,自引:0,他引:3
K C Wilhelmsen D E Weeks T G Nygaard C B Moskowitz R L Rosales D C dela Paz E E Sobrevega S Fahn T C Gilliam 《Annals of neurology》1991,29(2):124-131
"Lubag" is an X-linked disorder causing dystonia and parkinsonism that has only been described in families from the Philippines, principally from the island of Panay. We have established linkage between the disease phenotype "lubag" and DNA markers which span the Xp11.22-Xq21.3 region by using a large Filipino family with 8 affected men in three generations. These DNA markers define an interval of about 20 centimorgans in the pericentromeric region of the X chromosome as the most likely site of the disease locus XDPD (X-linked dystonia-parkinsonism). XDPD has a maximum multipoint log likelihood ratio score (Zmax) of about 4.6 over the interval from Xq12 to Xq21.31 (DXS159-DXYS1X). The co-occurrence of dystonia and parkinsonism in lubag and in other known disorders suggests there may be a common pathogenetic mechanism. Identification of the genetic defect in this family may provide an important clue toward understanding the pathogenesis and pathophysiology of both dystonia and parkinsonism. 相似文献
9.
T. O. Rognum E. Thorud K. Elgjo P. Brandtzaeg H. Orjasaeter K. Nygaard 《British journal of cancer》1982,45(6):921-934
Immunofluorescence staining for carcinoembryonic antigen (CEA), secretory component (SC), and epithelial IgA was evaluated semiquantitatively in 85 large-bowel carcinomas in relation to degree of tumour differentiation, Dukes'' stage, and plasma CEA level. The tumours were divided into a near-diploid (ND, 28) and an aneuploid group (AN, 57) by means of flow-cytometric DNA measurements. Expression of SC and IgA in neoplastic epithelium was positively related to differentiation in both groups. The AN tumours scored significantly higher for CEA than the ND ones, but the staining was apparently unrelated to differentiation or Dukes'' stage. CEA expression in the transitional mucosa adjacent to ND tumours was negatively correlated with tumour differentiation, whereas epithelial IgA and SC in this zone showed a substantially higher positive correlation with tumour differentiation, and a somewhat stronger negative correlation with Dukes'' stage in the ND than in the AN group. Plasma CEA levels were significantly related to Dukes'' stage, only in patients with AN tumours, and only in this group were positively correlated with estimates of total tumour CEA for Dukes'' stages A and B. For Dukes'' stages C and D (disseminated tumours), moreover, the plasma CEA levels were found to be significantly higher in the AN group. These findings indicate that the DNA profile of large-bowel carcinomas is related both to the way neoplastic cells influence the activity of the transitional mucosa and their capacity for expression and release of epithelial products. AN tumours thus seem to be more active as "secretors" of CEA than ND ones. 相似文献
10.
Dedifferentiated clear cell chondrosarcoma 总被引:1,自引:0,他引:1
Kalil RK Inwards CY Unni KK Bertoni F Bacchini P Wenger DE Sim FH 《The American journal of surgical pathology》2000,24(8):1079-1086