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   848篇
  免费   53篇
  国内免费   1篇
耳鼻咽喉   1篇
儿科学   23篇
妇产科学   15篇
基础医学   145篇
口腔科学   15篇
临床医学   58篇
内科学   161篇
皮肤病学   15篇
神经病学   71篇
特种医学   16篇
外科学   213篇
综合类   7篇
预防医学   46篇
眼科学   4篇
药学   49篇
中国医学   5篇
肿瘤学   58篇
  2023年   4篇
  2022年   23篇
  2021年   20篇
  2020年   9篇
  2019年   8篇
  2018年   25篇
  2017年   23篇
  2016年   20篇
  2015年   22篇
  2014年   23篇
  2013年   37篇
  2012年   50篇
  2011年   62篇
  2010年   30篇
  2009年   25篇
  2008年   50篇
  2007年   44篇
  2006年   43篇
  2005年   45篇
  2004年   31篇
  2003年   39篇
  2002年   28篇
  2001年   17篇
  2000年   19篇
  1999年   10篇
  1998年   6篇
  1997年   5篇
  1996年   4篇
  1995年   11篇
  1994年   5篇
  1992年   14篇
  1991年   11篇
  1990年   13篇
  1989年   7篇
  1988年   13篇
  1987年   10篇
  1986年   9篇
  1985年   9篇
  1984年   4篇
  1981年   3篇
  1979年   9篇
  1978年   4篇
  1976年   4篇
  1975年   3篇
  1974年   8篇
  1973年   8篇
  1971年   3篇
  1970年   5篇
  1967年   4篇
  1966年   4篇
排序方式: 共有902条查询结果,搜索用时 156 毫秒
1.
2.
One hundred thirty-nine cemented and 132 cementless Miller-Galante total knee prostheses were followed between three and six years (average, 43-44 months). The fixation technique was based on patient age, bone quality, and ability to delay full-weight bearing. Clinical follow-up studies were possible on 116 cemented knees. Fifteen knees were lost because of death before the three-year follow-up study, and eight knees required component removal. One hundred twenty-three cementless knees were available for clinical follow-up studies; there were three deaths, and six failures required component removal. No cemented failure was due to fixation, and three cementless failures were due to lack of tibial ingrowth in two and pain of undetermined etiology in one. Preoperative knee scores were slightly significant with cemented knees averaging 48 points and cementless knees averaging 52 points. A similar significant difference was maintained at the final follow-up study. No significant differences were noted for pain, limp, or support scores. Average range of motion was similar in the two groups. Radiolucent lines about the femoral component were rare. Cementless tibial radiolucencies were partial in up to 20% of examined zones, and complete tibial tray radiolucency was seen in only three patients. No correlation between radiolucency and knee scores was seen.  相似文献   
3.
In spite of previous reports on the relationship between ongoing EEG and ERPs, there remains a lack of agreement on the nature of their nexuses. The aim of the present study was to evaluate the relationship between resting EEG and the ERP components in two groups of healthy subjects with different levels of performance in a highly demanding selective visual attention task. Young adults were classified according to the amount of their correct responses in the task, into high (HP; averaged hits (AH): 86%) and low performance groups (LP; AH: 59%). EEG was recorded during rest, prior to task performance and absolute (AP) and relative power (RP), as well as inter- (rTER) and intrahemispheric (rTRA) correlation were calculated. ERPs during task performance were also obtained and their amplitude and latency measures were assessed. Results showed that individuals with better behavioral performance had a higher synchronization between both hemispheres during rest as well as higher amplitude and shorter latencies of N2 and P3. Principal Component Analysis revealed that alpha2 AP and RP were inversely related to P2 and N2 latency. Higher values of alpha1 and alpha2 rTER were clustered with higher P3 amplitude and shorter reaction time. In conclusion, the differences in the cortical organization of HP and LP at rest (EEG) seem to be associated to the way the brain reacts during information processing (ERPs).  相似文献   
4.
Autogenous cancellous bone and freeze-dried allogeneic cancellous bone were tested in a total of 41 adult male mongrel dogs. In each humerus, an implant with a commercially pure titanium fiber metal porous coating was placed in an overreamed cavity so that a uniform 3-mm gap was present between the implant and host cancellous bone. Graft material was placed in the gap of one humerus while the gap of the other humerus was left empty and served as a paired negative control. Histologically, both autograft and allograft appeared to aid repair of the defect, but quantitatively only autograft enhanced new bone formation within the defect. Treatment with autograft significantly increased the amount of bone ingrowth within the implants by nearly three-fold at 4 weeks and eight-fold at 8 weeks. The enhancing effect was recognizable as early as 2 weeks. The strength of fixation was increased by nearly seven-fold at 4 weeks and two-fold at 8 weeks in the autograft group, but this was only statistically significant at 4 weeks. Treatment with allograft did not enhance bone ingrowth at any time period, but had a small positive effect on strength of fixation at 4 weeks.  相似文献   
5.
Between 1982 and 1988, 111 elderly women with breast cancer but without clinical involvement of the axillary lymph nodes underwent wide lumpectomy in a Day Hospital regimen at the National Cancer Institute of Milan. The patients ranged in age from 70 to 92 years (median, 79). An adjuvant treatment was carried out in all but 9 cases: tamoxifen only in 84 cases, tamoxifen plus radiotherapy in 6 cases, radiotherapy alone in 12 cases. The median duration of follow-up was 44 months (range, 30-109 months). Four patients (3.6%) were lost to follow-up. In the remaining 107 patients, 10 local-regional relapses (9.1%) and 7 distant metastases (6.5%) occurred. Six patients died from the disease, 14 from unrelated conditions. This retrospective study showed that selected elderly patients with breast cancers can be treated successfully under local anesthesia on an outpatient basis. The treatment guarantees local control of the disease, meets the favor of elderly women and consequently improves their quality of life.  相似文献   
6.
A non-weight-bearing porous-coated rod was implanted bilaterally in the proximal part of the humerus in thirty-five adult male mongrel dogs. In all of the animals, one limb was treated with radiation and the opposite limb served as the control. In twenty-one animals, the dose was 1000 centigrays (rads) and in fourteen, it was 500 centigrays. The strength of fixation and the volume fraction of ingrowth of bone were determined two, four, and eight weeks after the operation in the group that received 1000 centigrays and two and four weeks after the operation in the group that received 500 centigrays. Treatment with 500 centigrays had no significant effect on the strength of fixation or the amount of ingrowth of bone. In contrast, at two weeks, treatment with 1000 centigrays had reduced the strength of fixation to 50 per cent of the control value (p less than 0.01), although, at four and eight weeks, the strength of fixation was not significantly different than that in the control limb. The amount of ingrowth of bone in the irradiated limb was significantly reduced at two weeks (30 per cent of the control value) (p less than 0.01), four weeks (70 per cent of the control value) (p less than 0.05), and eight weeks (56 per cent of the control value) (p less than 0.05).  相似文献   
7.
The clinical efficacy and the safety of ciprofloxacin was studied in 92 patients (aged 26 to 83 years; mean 57.5 years) affected by urinary tract infections (UTI) and respiratory tract infections (RTI) suffering also with various liver diseases. Ciprofloxacin was given orally at different dose regimens: 500 mg b.i.d. (22 cases), 250 mg b.i.d. (20 cases), 500 mg s.i.d. (20 cases) for the treatment of UTIs; 500 mg b.i.d. (ten cases) and 250 mg b.i.d. (20 cases) for the treatment of RTIs. The doses were not correlated to the severity of the infections. Patients were treated for five to 15 days. All the bacteria isolated from sputum or urine before treatment were sensitive to ciprofloxacin (MIC range 0.015 mg/1 to 8 mg/1). The clinical and bacteriological responses were favourable in a high percentage of patients both for RTIs and UTIs, irrespective of the dose. Side effects were infrequent (7%) and mild (nausea, gastralgia, oral candidosis), never requiring the interruption of the treatment. No change in the blood chemistry tests was observed at any dose.Die klinische Wirksamkeit und Sicherheit von Ciprofloxacin wurde bei 92 Patienten (Alter 26 bis 83 Jahre, im Mittel 57,5 Jahre), die an verschiedenen Leberkrankheiten litten, bei interkurrent aufgetretenen Harnwegs- und Atemwegsinfektionen geprüft. Ciprofloxacin wurde in verschiedenen Dosierungen oral verabreicht. Zur Behandlung von Harnwegsinfektionen wurden Dosierungen von 500 mg zweimal täglich (22 Fälle), 250 mg zweimal täglich (20 Fälle) oder 500 mg in einer täglichen Einzeldosis (20 Fälle) verabreicht. Atemwegsinfektionen wurden mit zweimal täglich 500 mg (10 Fälle) oder mit zweimal täglich 250 mg (20 Fälle) behandelt. Die Dosen wurden nicht nach dem Schweregrad der Erkrankung gewählt. Die Behandlungsdauer betrug fünf bis 15 Tage. Alle aus Sputum oder Urin vor der Therapie isolierten Bakterien waren für Ciprofloxacin empfindlich (MHK-Werte 0,015 mg/l bis 8 mg/l). Bei einem hohen Prozentsatz der Patienten mit Atemwegs- und Harnwegsinfektionen wurden unabhängig von der Dosierung günstige klinische und bakteriologische Ergebnisse erzielt. Nebenwirkungen traten selten auf (7%) und waren leicht (Übelkeit, Magenschmerzen, orale Candidiasis). Ein Therapieabbruch war in keinem Fall nötig. Bei keiner der angewandten Dosierungen waren Änderungen in den klinisch-chemischen Parametern festzustellen.  相似文献   
8.
Sonography detected a paraaortic pulsatile tubular mass in a patient 10 years after “stump” nephrectomy, which was subsequently confirmed as a renal artery-renal vein fistula by computed tomography, angiography, and laparotomy.  相似文献   
9.
Abnormally high wear rates of ultra high molecular weight polyethylene have been associated with sliding against freshly polished titanium. The wear rate can be brought to the level associated with stainless steel and cast Co-Cr-Mo alloy on polyethylene by the growth of a passive film on titanium. This can be accomplished either in air at elevated temperatures or in oxidizing aqueous solutions.  相似文献   
10.
The effects of tolerance to Escherichia coli endotoxin on the phagocytic and bactericidal activity of the hepatic reticuloendothelial system against viable E. coli were examined using ex vivo perfused rat livers. Livers were isolated from control and endotoxin-tolerant rats and perfused with a medium containing 5% homologous serum from either control or tolerant rats. After the addition of the E. coli (2 × 107 cells per ml) to the perfusate, the hepatic clearance of the bacteria was followed for 30 min. The highest activation of the hepatic reticuloendothelial system was observed when serum from tolerant animals was added to the perfusate. Under these conditions phagocytosis was 47% (12% in controls), and 37 to 38% of the bacteria were killed (5% in controls). This activation was less when livers obtained from tolerant rats were perfused with serum from controls or with saline only. The data suggests that, during endotoxin tolerance, humoral factors play an important role in the activation of the hepatic reticulendothelial system, although a direct stimulation of Kupffer cells also occurs. The enhancement of phagocytosis by tolerant serum did not require the presence of homologous antibodies and involved the activation of the alternative complement pathway, since it was lost after removal of factor B activity. On the other hand, stimulation of intracellular killing required both complement and specific antibodies. The data suggest a role of endotoxin in the activation of humoral and cellular mechanisms involved in the host resistance to gram-negative bacterial infection.  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