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   295篇
  免费   23篇
  国内免费   7篇
儿科学   20篇
妇产科学   2篇
基础医学   64篇
口腔科学   8篇
临床医学   38篇
内科学   41篇
皮肤病学   13篇
神经病学   4篇
特种医学   31篇
外科学   35篇
综合类   17篇
一般理论   1篇
预防医学   14篇
眼科学   4篇
药学   18篇
中国医学   4篇
肿瘤学   11篇
  2023年   4篇
  2022年   4篇
  2021年   8篇
  2020年   7篇
  2019年   6篇
  2018年   11篇
  2017年   11篇
  2016年   12篇
  2015年   10篇
  2014年   23篇
  2013年   19篇
  2012年   13篇
  2011年   12篇
  2010年   10篇
  2009年   7篇
  2008年   7篇
  2007年   13篇
  2006年   6篇
  2005年   7篇
  2004年   3篇
  2003年   4篇
  2002年   12篇
  2001年   8篇
  2000年   4篇
  1999年   4篇
  1998年   6篇
  1996年   8篇
  1995年   6篇
  1994年   6篇
  1993年   8篇
  1992年   2篇
  1991年   3篇
  1990年   5篇
  1989年   8篇
  1988年   11篇
  1987年   7篇
  1986年   7篇
  1985年   8篇
  1984年   1篇
  1983年   3篇
  1982年   3篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
  1977年   2篇
  1975年   2篇
  1966年   1篇
排序方式: 共有325条查询结果,搜索用时 0 毫秒
1.
A unique case of a malignant oncocytoma of the maxillary sinus is reviewed in detail. The ultrastructural findings are presented. The histologic and ultrastructural criteria that characterize onco-cytes and the clinicopathologic features of benign and malignant oncocytomas are discussed. This case represents the eleventh reported case that would truly qualify as a malignant oncocytoma of the paranasal sinuses.  相似文献   
2.
HLA polymorphisms in Nigerians   总被引:2,自引:0,他引:2  
The HLA class I and class II phenotypes of a panel of 114 unrelated Nigerians have been determined. The panel was tested for all the known class I antigens and comparisons of the HLA-A and -B frequencies with those of other African Negroid populations revealed some differences. Only limited comparisons could be made for the HLA-DR and -D frequencies as these are not available for any well-defined African Negroid population. The data concerning the class II antigens of this panel are the most interesting. Half of the DRw11-positive panel members are DQw3 negative and DQw1 positive. In addition, there is dissociation of some HLA-D and -DR specificities, a number of panel members are positive for an HLA-D specificity and are negative for the corresponding HLA-DR specificity. Our results show the value of population studies in the investigation of the relationship between the different HLA class II antigens.  相似文献   
3.
Embryonally bursectomised and nonbursectomised chickens were infected with infectious bursal disease virus (IBDV) at 36 days of age. Neither clinical signs nor gross lesions were observed in the infected, bursectomised (IB) chickens. No significant changes were observed in carcass, thymus or spleen weights of IB and noninfected bursectomised chickens. A mild lymphocytic necrosis and depletion were found in the spleen, thymus and caecal tonsil of the IB chickens. Neither precipitating nor serum neutralising antibodies were detected in the sera but IBDV was reisolated from the spleen and thymus. Infected, nonbursectomised (IN) chickens developed severe depression with diarrhoea and high mortalities. Haemorrhages were found in the muscles of the breast and thigh, proventriculus and intestines. Significant changes were observed between the carcass, thymus and bursa weights of the IN and noninfected, nonbursectomised chickens. There was severe lymphatic necrosis of the bursa, thymus, spleen and caecal tonsil. Both precipitating and neutralising antibodies were detected in the sera and the virus was reisolated from the bursa, thymus and spleen. It is concluded that the bursa of Fabricius is not essential for the establishment of an IBDV infection but is required for the clinical infection.  相似文献   
4.
BackgroundDisseminated intravascular coagulation (DIC) is one of the commonest causes of abnormal bleeding during pregnancy and puerperium. Its successful management is a challenging feat in resource limited settings (RLS).AimTo determine Obstetricians'' approach in diagnosing and treating obstetrics DIC in a RLSMethodA semi-structured pre-tested 4-sectioned questionnaire was used to collect demographic data of Nigerian obstetricians and data on their practice in the diagnosis and treatment of obstetrics DIC.ResultsA total of 171 obstetricians responded. Preeclampsia was the most frequent cause identified (70.2%) followed by postpartum haemorrahge (58.3%). Platelet count determination was the test mostly used (95.9%) to make a diagnosis of DIC whereas, antithrombin assay was the least (20.6%) requested investigation. While about two-third would monitor the evolution of DIC, a little less than half of the obstetricians would not repeat laboratory testing more than every 2 days, reason mainly (61.8%) due to patient''s financial constraint. Almost three-quarter of them preferred fresh whole blood as the first line of treatment of DIC.ConclusionDIC remains a challenge in the obstetrics practice in RLS especially in investigations, monitoring and index of suspicion for non-overt DIC.  相似文献   
5.
6.
McGee  MP; Wallin  R; Wheeler  FB; Rothberger  H 《Blood》1989,74(5):1583-1590
We examined assembly and expression of the factor X activating complex on human and rabbit alveolar macrophages. Kinetic parameters of the factor X activating reaction were determined by functional titrations of factors VII and X with macrophage tissue factor (TF) added. We found rapid activation of factor X to Xa on alveolar macrophage surfaces. Detection of rapid factor Xa formation on macrophages required addition of exogenous factors VII and X. At plasma concentrations of the purified factors, factor Xa was formed on freshly isolated macrophages at approximately 5.4 pmol/min/10(6) cells. After macrophage maturation in culture for 20 hours with LPS (endotoxin) added, the factor X activation rate was increased two- to sixfold. The km' (apparent km) of TF-factor VII enzymatic complexes assembled on alveolar macrophages for factor X were (258 +/- 55 and 475 +/- 264 nmol/L for human and rabbit cells, respectively). The km' did not change during macrophage maturation in culture, but V'max (apparent Vmax) was consistently increased. The K1/2 of human factor VII (concentrations giving half maximal rates of factor X activation) for the interaction with human and rabbit alveolar macrophage TF were 0.191 +/- 0.096 and 1.7 +/- 0.7 etamol/L, respectively. The K1/2 were not significantly changed after maturation, whereas rates of Xa formation at saturation with factor VII were increased. The fast rates of factor X activation observed at physiologic concentrations of plasma-derived factors VII and X indicate that TF on alveolar macrophages is likely to provide sites for binding of factor VII and activation of factor X in vivo during clotting reactions associated with alveolar edema and inflammation.  相似文献   
7.
Introduction:Human Immunodeficiency Virus (HIV) infection remains prevalent co-morbidity, and among fracture patients. Few studies have investigated the role of exercise interventions in preventing bone demineralization in people who have fractures and HIV. If exercise exposed, HIV-infected individuals may experience improved bone health outcomes (BMD), function, quality of life (QoL). The study will aim to assess the impact of home based exercises on bone mineral density, functional capacity, QoL, and some serological markers of health in HIV infection among Nigerians and South Africans.Methods and design:The study is an assessor-blinded randomized controlled trial. Patients managed with internal and external fixation for femoral shaft fracture at the study sites will be recruited to participate in the study. The participants will be recruited 2 weeks post-discharge at the follow-up clinic with the orthopaedic surgeon. The study population will consist of all persons with femoral fracture and HIV-positive and negative (HIV-positive medically confirmed) aged 18 to 60 years attending the above-named health facilities. For the HIV-positive participants, a documented positive HIV result, as well as a history of being followed-up at the HIV treatment and care center. A developed home based exercise programme will be implemented in the experimental group while the control group continues with the usual rehabilitation programme. The primary outcome measures will be function, gait, bone mineral density, physical activity, and QoL.Discussion:The proposed trial will compare the effect of a home-based physical exercise-training programme in the management of femoral fracture to the usual physiotherapy management programmes with specific outcomes of bone mineral density, function, and inflammatory markers.Trial registration:The study was prospectively registered with the Pan African Clinical Trials Registry (Reference number – PACTR201910562118957) on October 21, 2019. (https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=9425).  相似文献   
8.
9.
10.

Background

Transmediastinal gunshot wounds are associated with a high mortality and frequently require operative intervention. The purpose of this study was to identify the diagnostic and therapeutic challenges of these injuries in a mature trauma system with decreasing prehospital time intervals.

Methods

Patients admitted to a large urban Level 1 trauma centre between 1/2006 and 12/2010 sustaining a firearm injury to the torso were identified. Transmediastinal gunshot wounds were defined as missile tracts traversing the mediastinum identified on CT images, operative notes or autopsy reports.

Results

Overall, 133 patients met study criteria. A total of 116 patients (87.2%) were haemodynamically unstable or had no vital signs on arrival to the Emergency Department. Ninety-seven (83.6%) of these patients required a resuscitative thoracotomy resulting in 8 survivors (6.0%). There were 17 haemodynamically stable patients (12.8%) identified, 14 of whom underwent CT scan evaluation. Six patients subsequently required operative intervention. Only 11 patients (8.3%) in the study population were successfully managed nonoperatively. The overall mortality was 78.9%, and for those who reached the hospital with vital signs, the mortality was 24.3%.

Conclusions

Transmediastinal gunshot wounds encountered in a mature trauma centre are highly lethal injuries requiring resuscitative thoracotomy in most instances. Changing perspectives in these injuries may reflect the effects of an evolving prehospital care.  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