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   806篇
  免费   30篇
  国内免费   3篇
耳鼻咽喉   2篇
儿科学   37篇
妇产科学   11篇
基础医学   74篇
口腔科学   15篇
临床医学   77篇
内科学   169篇
皮肤病学   10篇
神经病学   29篇
特种医学   251篇
外科学   32篇
综合类   19篇
预防医学   40篇
眼科学   7篇
药学   35篇
  1篇
中国医学   8篇
肿瘤学   22篇
  2021年   3篇
  2018年   3篇
  2017年   3篇
  2016年   4篇
  2015年   10篇
  2014年   5篇
  2013年   9篇
  2012年   7篇
  2011年   21篇
  2010年   25篇
  2009年   23篇
  2008年   13篇
  2007年   13篇
  2006年   19篇
  2005年   17篇
  2004年   6篇
  2003年   10篇
  2002年   9篇
  2001年   4篇
  2000年   10篇
  1999年   10篇
  1998年   37篇
  1997年   36篇
  1996年   35篇
  1995年   46篇
  1994年   38篇
  1993年   38篇
  1992年   10篇
  1991年   4篇
  1990年   16篇
  1989年   41篇
  1988年   25篇
  1987年   30篇
  1986年   42篇
  1985年   23篇
  1984年   20篇
  1983年   16篇
  1982年   17篇
  1981年   19篇
  1980年   20篇
  1979年   10篇
  1978年   19篇
  1977年   17篇
  1976年   14篇
  1975年   14篇
  1970年   2篇
  1959年   2篇
  1958年   4篇
  1957年   6篇
  1954年   3篇
排序方式: 共有839条查询结果,搜索用时 31 毫秒
71.
Background: A continuous popliteal sciatic nerve block (CPSNB) has been performed with increasing frequency for post‐operative analgesia after foot surgery. Major complications associated with the placement of a perineural catheter remain rarely studied. The aim of this study was to prospectively determine the incidence of major complications (neurological and infectious) in post‐operative adult patients with a continuous popliteal catheter inserted by the anatomical posterior approach for analgesia after foot surgery. Methods: All popliteal catheters were placed pre‐operatively under sterile conditions with the aid of a nerve stimulator technique. The primary outcome measure was the incidence of major complications including infection and neuropathy. As a secondary outcome, adverse effects as well as other complications were also evaluated. Data were expressed as median [25th–75th percentiles]. Results: A total of 400 patients were included in the study during a 2‐year period. The median time the catheter remained indwelling was 47 h [23, 54]. Major complications included three events (0.75%) with one infection (0.25%) and two neuropathies (0.50%). Three blocks were unsuccessful and the catheter insertion was difficult in 12 patients (3%). During the CPSNB procedure, one patient reported slight paraesthesia during stimulation. Patient satisfaction was scored at 4 for 89%, 3 for 6% and 2 for 5% on the analogue scale. Conclusions: Major complications after the use of CPSN are not in fact rare. The incidence of severe neuropathy or infection complications is, respectively, 0.50% and 0.25%. However, the insertion of CPSN could be considered effective and is associated with only a few minor complications.  相似文献   
72.
BACKGROUND: There is a need to identify effective practical interventions to decrease cardiovascular disease risk in patients with diabetes. OBJECTIVE: We examine the impact of participation in a collaborative implementing the chronic care model (CCM) on the reduction of cardiovascular disease risk in patients with diabetes. DESIGN: Controlled pre- and postintervention study. PATIENTS/PARTICIPANTS: Persons with diabetes receiving care at 13 health care organizations exposed to the CCM collaborative and controls receiving care in nonexposed sites. MEASUREMENTS AND MAIN RESULTS: Ten-year risk of cardiovascular disease; determined using a modified United Kingdom Prospective Diabetes Study risk engine score. A total number of 613 patients from CCM intervention sites and 557 patients from usual care control sites met the inclusion criteria. The baseline mean 10-year risk of cardiovascular disease was 31% for both the intervention group and the control group. Participants in both groups had improved blood pressure, lipid levels, and HbA1c levels during the observation period. Random intercept hierarchical regression models showed that the intervention group had a 2.1% (95% CI -3.7%, -0.5%) greater reduction in predicted risk for future cardiovascular events when compared to the control group. This would result in a reduced risk of one cardiovascular disease event for every 48 patients exposed to the intervention. CONCLUSIONS: Over a 1-year interval, this collaborative intervention using the CCM lowered the cardiovascular disease risk factors of patients with diabetes who were cared for in the participating organization's settings. Further work could enhance the impact of this promising multifactorial intervention on cardiovascular disease risk reduction.  相似文献   
73.
目的:探讨三维适形放疗结合锎(252Cf)中子腔内后装照射治疗中晚期食管癌的疗效、不良反应及晚期并发症。方法:92例中晚期食管癌患者全部采用三维适形放疗结合锎(252Cf)中子腔内后装照射治疗。三维适形放疗总剂量为45Gy-54Gy,分25-30次,5-6周完成;腔内照射3-4Gy/次,1次/周,共2-4次,总吸收剂量10Gy-16Gy。结果:治疗结束3个月进食梗阻缓解率为95%。近期疗效:完全缓解(CR)27%,部分缓解(PR)69.6%。1、2、3年局部控制率分别为82%、51%、32%;1、2、3年生存率分别为:78%、35%、18%;急性放射性食管炎发生率为54%;晚期食管狭窄发生率9%;食管穿孔发生率2%。结论:中晚期食管癌采用三维适形放疗结合锎(252Cf)中子腔内后装照射能够迅速而持久地缓解进食梗阻症状,提高局部控制率及生活质量,近期疗效显著,放疗不良反应未见明显增加。  相似文献   
74.
目的 了解应用IHA、ELISA检测鼠疫F1抗体的一致性,评价方法的优劣,以便更好地制订鼠疫监测的方法及防治策略.方法 对广西鼠疫监测点隆林、西林县的犬血清使用IHA及ELISA两种试验方法,并进行一致性研究,评价IHA与ELISA方法的可靠性.结果 IHA检测鼠疫F1抗体阳性率为0,ELISA检测鼠疫F1抗体的总阳性率为4.4%(12/273);IHA与ELISA之间的一致性为95.6%,其Kappa值等于0,呈轻度一致.结论 间接血凝试验方法特异、操作简便是传统的鼠疫监测手段之一;酶联免疫吸附试验具有敏感性高、特异性强、操作简便等特点,且与间接血凝试验有轻度一致性,适宜在鼠疫监测中推广应用.  相似文献   
75.
FA Chiafari  ; RE Wenk 《Transfusion》1990,30(7):648-650
Single-locus DNA probes for tandem repeat sequences are now used in conjunction with particular endonucleases to characterize heritable restriction fragment lengths in parentage tests. Southern blots of this type, however, demonstrate only two attributes of an allele: its length and the presence of nucleotide sequences that are complementary to the probe. Not all restriction fragments of the same apparent length that react with the same probe are identical. Differences between comigrating fragments can be detected by the selection of a restriction enzyme that recognizes sites in a subset of the repeat sequences, and the information content of these loci is therefore increased. This report describes a paternity case in which two brothers appeared, after DNA phenotyping using Hinf I, to be the father. A second phenotyping using Hae III excluded one of the brothers.  相似文献   
76.
We investigated the basis for a novel form of the slow-channel congenital myasthenic syndrome presenting in infancy in a single individual as progressive weakness and impaired neuromuscular transmission without overt degeneration of the motor endplate. Prolonged low-amplitude synaptic currents in biopsied anconeus muscle at 9 years of age suggested a kinetic disorder of the muscle acetylcholine receptor. Ultrastructural studies at 16 months, at 9 years, and at 15 years of age showed none of the typical degenerative changes of the endplate associated with the slow-channel congenital myasthenic syndrome, and acetylcholine receptor numbers were not significantly reduced. We identified a novel C-to-T substitution in exon 8 of the delta-subunit that results in a serine to phenylalanine mutation in the region encoding the second transmembrane domain that lines the ion channel. Using Xenopus oocyte in vitro expression studies we confirmed that the deltaS268F mutation, as with other slow-channel congenital myasthenic syndrome mutations, causes delayed closure of acetylcholine receptor ion channels. In addition, unlike other mutations in slow-channel congenital myasthenic syndrome, this mutation also causes delayed opening of the channel, a finding that readily explains the marked congenital weakness in the absence of endplate degeneration. Finally, we used serial morphometric analysis of electron micrographs to explore the basis for the progressive weakness and decline of amplitude of endplate currents over a period of 14 years. We demonstrated a progressive widening and accumulation of debris in the synaptic cleft, resulting in loss of efficacy of released neurotransmitter and reduced safety factor. These studies demonstrate the role of previously unrecognized mechanisms of impairment of synaptic transmission caused by a novel mutation and show the importance of serial in vitro studies to elucidate novel disease mechanisms.  相似文献   
77.
Blunt traumatic aortic rupture: detection with helical CT of the chest   总被引:7,自引:1,他引:6  
  相似文献   
78.
79.
Sleep processes and body temperature regulation of neonates are never taken into account in the evaluation of nutrients, although these functions are implicated in the regulation of energy metabolism and are influenced by the nutritional state and its metabolic consequences. Medium-chain triglycerides (MCT) are currently used in paediatric units during the first weeks of because they are considered to be a rapid source of energy, easy to assimilate for growing premature infants, whose digestive function is immature. However, no study has described the thermic effect of these nutrients on body temperature regulation and sleep. The present study aimed at analysing the influence of three feeding formulas with different content of MCT on sleep processes and on thermoregulation of neonates fed until desired intake was reached. Whatever the thermal conditions (thermal equilibrium or cool environment), the MCT-fed groups had higher body temperatures and than groups fed without MCT, for whom total sleep time was reduced at thermal equilibrium. In this group, the large amount of quiet sleep seems to favour a strategy of conserving energy . Higher energy expenditure in MCT-fed groups is not harmful to growth rate since nutritional efficiency is even better reflected by a larger body mass gain. The thermic effect of MCT contributes to lessening the vulnerability of neonates exposed to low incubator temperatures.  相似文献   
80.
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