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   78篇
  免费   2篇
  国内免费   3篇
儿科学   1篇
基础医学   18篇
临床医学   5篇
内科学   24篇
特种医学   9篇
外科学   11篇
预防医学   2篇
眼科学   1篇
药学   3篇
肿瘤学   9篇
  2022年   1篇
  2021年   7篇
  2019年   3篇
  2018年   3篇
  2017年   1篇
  2014年   1篇
  2013年   2篇
  2012年   3篇
  2011年   1篇
  2010年   1篇
  2008年   3篇
  2007年   2篇
  2006年   1篇
  2005年   2篇
  2004年   3篇
  2003年   2篇
  2002年   3篇
  2001年   2篇
  2000年   1篇
  1999年   4篇
  1998年   2篇
  1997年   1篇
  1993年   2篇
  1992年   3篇
  1991年   1篇
  1990年   3篇
  1987年   1篇
  1986年   2篇
  1985年   4篇
  1984年   5篇
  1983年   2篇
  1982年   2篇
  1980年   2篇
  1979年   1篇
  1978年   4篇
  1977年   2篇
排序方式: 共有83条查询结果,搜索用时 31 毫秒
1.
The structure of hard tissue areas (with osteoid and calcified matrix) in 10 osteoblastic, chondroblastic, and fibroblastic osteogenic sarcomas was studied in the electron microscope. Neoplastic cells commonly associated with these areas and presumably actively involved in the production of hard tissue were osteo-blastlike cells types 1 and 3, chondroblastlike cells type 1, and fibroblastlike cells, as defined and characterized in previous studies. The cells differed from those in soft tissue areas of osteogenic sarcomas in but one respect: they usually showed presence of irregular extrusions at their surfaces. Other types of osteoblastlike and chondroblastlike cells occurred rarely or not at all. Two types of multinucleated giant cells were recognized in these areas, one showing a fine structure reminiscent of that in osteoclasts, the other probably being of a neoplastic nature and engaged in the production of the calcifying matrix. The evidence suggested that neoplastic osteoblastlike, chondroblastlike, and fibrolastlike cells as well as certain multincleated giant cells might all be involved in the mineralization process and/or the formation of osteoid in osteogenic sarcomas. Although phenotypically of highly variable appearance, all these different cells may thus functionally (and probably histogenetically) be closely related.

The mineralization process in the tumor tissue appeared to be a modification of what occurs in normal ossification, possibly with an alternative or complementary pathway involving the production of spherical bodies with layered contents.  相似文献   
2.
BackgroundObesity has been described as a protective factor in cardiovascular and other diseases being expressed as ‘obesity paradox’. However, the impact of obesity on clinical outcomes including mortality in COVID-19 has been poorly systematically investigated until now. We aimed to compare clinical outcomes among COVID-19 patients divided into three groups according to the body mass index (BMI).MethodsWe retrospectively collected data up to May 31st, 2020. 3635 patients were divided into three groups of BMI (<25 kg/m2; n = 1110, 25?30 kg/m2; n = 1464, and >30 kg/m2; n = 1061). Demographic, in-hospital complications, and predictors for mortality, respiratory insufficiency, and sepsis were analyzed.ResultsThe rate of respiratory insufficiency was more recorded in BMI 25?30 kg/m2 as compared to BMI < 25 kg/m2 (22.8% vs. 41.8%; p < 0.001), and in BMI > 30 kg/m2 than BMI < 25 kg/m2, respectively (22.8% vs. 35.4%; p < 0.001). Sepsis was more observed in BMI 25?30 kg/m2 and BMI > 30 kg/m2 as compared to BMI < 25 kg/m2, respectively (25.1% vs. 42.5%; p = 0.02) and (25.1% vs. 32.5%; p = 0.006). The mortality rate was higher in BMI 25?30 kg/m2 and BMI > 30 kg/m2 as compared to BMI < 25 kg/m2, respectively (27.2% vs. 39.2%; p = 0.31) (27.2% vs. 33.5%; p = 0.004). In the Cox multivariate analysis for mortality, BMI < 25 kg/m2 and BMI > 30 kg/m2 did not impact the mortality rate (HR 1.15, 95% CI: 0.889?1.508; p = 0.27) (HR 1.15, 95% CI: 0.893?1.479; p = 0.27). In multivariate logistic regression analyses for respiratory insufficiency and sepsis, BMI < 25 kg/m2 is determined as an independent predictor for reduction of respiratory insufficiency (OR 0.73, 95% CI: 0.538?1.004; p = 0.05).ConclusionsHOPE COVID-19-Registry revealed no evidence of obesity paradox in patients with COVID-19. However, Obesity was associated with a higher rate of respiratory insufficiency and sepsis but was not determined as an independent predictor for a high mortality.  相似文献   
3.
Purpose To identify clinical and biologic variables with significant impact on survival in patients with carcinomas of an unknown primary site (CUP) and to develop a simple prognostic model. Patients and methods In this retrospective study, univariate and multivariate prognostic factors analyses were conducted in a population of 100 patients with CUP. Patients with features requiring well defined treatments had previously been excluded. Results Overall survival (OS) was significantly related to the following pretreatment adverse prognostic clinical factors: a poor performance status (2 or 3), weight loss more than 10% in the last six months, the presence of liver metastases and more than two metastatic sites. Two biological parameters predicted a significantly shorter survival: elevated serum levels of alkaline phosphatase and of lactate dehydrogenase. In the multivariate analysis, only two independent adverse prognostic parameters were retained: a poor performance status and the presence of liver metastases. We developed a prognostic model for OS based on the following subgroups: good prognosis (PS 0 or 1 and absence of liver metastases), intermediate prognosis (PS≥2 or presence of liver metastases) and poor prognosis (PS≥2 or presence of liver metastases). Median OS for the three groups was 10.8, 4 and 1.9 months respectively, p<0.0001. Conclusion A simple prognostic model using performance status and presence of liver metastases was developed. It allowed the assignment of patients into three subgroups with different outcomes. Treatment strategies could be adapted for each subgroup. We think that this prognostic model could be useful and should be validated in other patient series.  相似文献   
4.
Introduction and objectivesCoronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2. Atrial fibrillation (AF) is common in acute situations, where it is associated with more complications and higher mortality.MethodsAnalysis of the international HOPE registry (NCT04334291). The objective was to assess the prognostic information of AF in COVID-19 patients. A multivariate analysis and propensity score matching were performed to assess the relationship between AF and mortality. We also evaluated the impact on mortality and embolic events of the CHA2DS2-VASc score in these patients.ResultsAmong 6217 patients enrolled in the HOPE registry, 250 had AF (4.5%). AF patients had a higher prevalence of cardiovascular risk factors and comorbidities. After propensity score matching, these differences were attenuated. Despite this, patients with AF had a higher incidence of in-hospital complications such as heart failure (19.3% vs 11.6%, P = .021) and respiratory insufficiency (75.9% vs 62.3%, P = .002), as well as a higher 60-day mortality rate (43.4% vs 30.9%, P = .005). On multivariate analysis, AF was independently associated with higher 60-day mortality (hazard ratio, 1.234; 95%CI, 1.003-1.519). CHA2DS2-VASc score acceptably predicts 60-day mortality in COVID-19 patients (area ROC, 0.748; 95%CI, 0.733-0.764), but not its embolic risk (area ROC, 0.411; 95%CI, 0.147-0.675).ConclusionsAF in COVID-19 patients is associated with a higher number of complications and 60-day mortality. The CHA2DS2-VASc score may be a good risk marker in COVID patients but does not predict their embolic risk.  相似文献   
5.
Responsiveness was assessed to a programme of vaccination of hepatitis B vaccine in a cohort of 197 intravenous drug addicts (mean age, 23.7 years) and their antibody response was compared with that of 271 healthy controls (mean age, 24.2 years). All participants were seronegative for hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs). The vaccination schedule consisted of three intramuscular injections (deltoid area) at months 0, 1 and 2. Although 70% of parenteral drug abusers received the three doses of vaccination, only 43.6% were evaluable for immune response. Fifty-eight per cent of heroin addicts and 80% of controls had evidence of anti-HBs seroconversion at 1 month after vaccination (chi 2 = 15.52, p less than 0.001). Geometric mean antibody titres were also significantly higher in controls (69.1 IU l-1; confidence interval 95%, 56.83 and 84.04) than in parenteral drug abusers (18.2 IU l-1; confidence interval 95%, 12.85 and 25.73) (F = 20.951, p less than 0.0001). The anti-HBs response was not influenced by coexistent anti-HBc, HCV antibody or HIV antibody seropositivity.  相似文献   
6.
Osteoid osteoma (OO) is a benign skeletal neoplasm. Twenty-eight patients with proven OO were studied with MRI regarding soft tissue involvement which was diagnosed when high proton-density and T2-weighted signal intensity and low signal intensity on T1-weighted images were found close to bone. Most tumors were located in the femur and tibia; 6 cases diaphyseal, 12 metaphyso-diaphyseal, and 10 epiphyseal. In relation to the cortex, 15 were located centrally or in its outer margin. Soft tissue involvement was found in 15 patients (53.6 %). A statistical relationship was found between soft tissue involvement and the tumor's location with regard to the cortex, being more frequent in peripherally located tumors. Therefore, soft tissue involvement is a frequent finding in peripherally located OO. Received 30 December 1996; Revision received 21 April 1997; Accepted 16 June 1997  相似文献   
7.
Summary The morphology of 26 cases of osteogenic sarcoma was studied using electron microscopic techniques, and the localization of acid and alkaline phosphatase activity at the ultrastructural level elucidated. Four different cells were present in the tumours: osteoblast-like, fibroblast-like, chondroblast-like, and multinucleated giant cells. The osteoblast-like cell was present in most of the tumours studied. Acid phosphatase activity was present in lysosome-like structures of almost all the cell-types studied. Alkaline phosphatase activity was noted in or on the plasma membranes and associated vesicles of osteoblast-like, fibroblast-like, and multinucleated giant cells. The abundant reaction product deposition of alkaline phosphatase as compared with the lower acid phosphatase activity is in agreement with the nature of this bone-forming tumour. The results of the histochemical studies have added to the understanding of the pathobiology of the different cells composing osteogenic sarcomas.
Résumé La morphologie de 26 sarcomes ostéogéniques a été étudiée par microscopie électronique et la localisation des phosphatases acide et alcaline a pu être précisée au niveau ultrastructural. Quatre différents types de cellules ont été mis en évidence dans les tumeurs: cellules d'aspect ostéoblastique, fibroblastique et chondroblastique, ainsi que des cellules géantes multinuclées. Les cellules d'aspect ostéoblastique étaient présentes dans presque toutes les tumeurs étudiées. Une activité phosphatasique acide a été trouvée dans les lysosomes de toutes les cellules étudiées. Une activité phosphatasique alcaline a été observée dans — ou sur — la membrane plasmatique et dans les vésicules associées des cellules d'aspect ostéoblastique et fibroblastique ainsi que des cellules géantes. L'abondance des produits de réaction de la phosphatase alcaline contrastant avec une faible activité phosphatasique acide est en accord avec la nature de cette tumeur ostéogénique. Les résultats de l'étude histochimique ont aidé à comprendre la pathobiologie des différentes cellules qui constituent les sarcomes ostéogéniques.
  相似文献   
8.
9.
10.
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