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   223篇
  免费   11篇
  国内免费   1篇
耳鼻咽喉   3篇
儿科学   3篇
妇产科学   5篇
基础医学   49篇
口腔科学   6篇
临床医学   14篇
内科学   25篇
皮肤病学   10篇
神经病学   10篇
特种医学   5篇
外科学   41篇
综合类   1篇
预防医学   4篇
眼科学   1篇
药学   24篇
肿瘤学   34篇
  2022年   2篇
  2021年   1篇
  2019年   2篇
  2017年   4篇
  2016年   1篇
  2015年   2篇
  2014年   3篇
  2013年   6篇
  2012年   8篇
  2011年   13篇
  2010年   3篇
  2009年   8篇
  2008年   12篇
  2007年   14篇
  2006年   18篇
  2005年   23篇
  2004年   20篇
  2003年   18篇
  2002年   13篇
  2001年   3篇
  2000年   3篇
  1999年   2篇
  1997年   7篇
  1996年   5篇
  1995年   4篇
  1994年   3篇
  1992年   4篇
  1991年   5篇
  1990年   1篇
  1989年   3篇
  1986年   3篇
  1985年   4篇
  1983年   1篇
  1982年   1篇
  1981年   4篇
  1980年   1篇
  1979年   1篇
  1978年   4篇
  1977年   1篇
  1976年   2篇
  1971年   1篇
  1966年   1篇
排序方式: 共有235条查询结果,搜索用时 0 毫秒
1.
Prostaglandins are inflammatory mediators that are believed to play an important role in the pathophysiology of periodontal disease. Prostaglandin H synthase (PGHS, EC 1.14.99.1) is the rate-limiting enzyme in prostaglandin biosynthesis. The enzyme exists as two separately encoded isoforms. PGHS-1 which is constitutively expressed and PGHS-2 which is induced by inflammatory stimuli. This is the first report describing the expression of the isoenzymes in gingival tissue from patients diagnosed with adult periodontitis. Tissue was fixed in an alcohol-based fixative and embedded in paraffin. Methods were developed using immunohistochemical controls, such that embedded sections could be processed and stained using isoform-specific antibodies and a peroxidase-antiperoxidase immunohistochemistry technique. Along with populations of mononuclear inflammatory cells, endothelial cells and fibroblasts, the gingival epithelial cell layer appears to be a rich and important source of prostaglandin production within the periodontium of patients with periodontitis as detected by this newly developed immunohistochemical staining technique for PGHS-1 and PGHS-2.  相似文献   
2.
Archival material from 47 patients with primary squamous cell carcinoma of the head and neck (SCCHN) was studied immunohistochemically for the presence of nm23-H1 protein. Our data indicate that nm23-H1 protein expression is a common event in SCCHN and that there is a trend toward correlation of increased expression of nm23-H1 with increasing tumor size (p = 0.072). The results also show that when adjusting for age and cause of death, there tended to be an inverse relationship between overall survival and the expression of nm23-H1 gene in the primary tumor (p = 0.088).  相似文献   
3.
Fifty-three patients with T1 squamous cell cancer of the floor of mouth and ventral surface of the tongue with a known clinical outcome were retrospectively analyzed and arbitrarily divided into “aggressive” and “nonaggressive” groups based on their clinical behavior. Various host and tumor factors were then evaluated in an attempt to determine whether the tumor behavior could have been predicted. The paraffin-embedded tumor specimens were evaluated for tumor differentiation, tumor thickness and tumor invasion, microvessel density, and p53 expression. In addition, a composite morphologic grading score was obtained by combining cell differentiation, nuclear polymorphism, mitosis activity, depth of infiltration, type of infiltration, and lymphatic infiltration. No single technique appeared capable of identifying “aggressive” behavior, although possibly an evaluation of composite factors might show promise in the future.  相似文献   
4.
Over a year into the COVID-19 pandemic, there is growing evidence that SARS-CoV-2 infections among dogs are more common than previously thought. In this study, the prevalence of SARS-CoV-2 antibodies was investigated in two dog populations. The first group was comprised of 1069 dogs admitted to the Veterinary Teaching Hospital for any given reason. The second group included dogs that shared households with confirmed COVID-19 cases in humans. This study group numbered 78 dogs. In COVID-19 infected households, 43.9% tested ELISA positive, and neutralising antibodies were detected in 25.64% of dogs. Those data are comparable with the secondary attack rate in the human population. With 14.69% of dogs in the general population testing ELISA positive, there was a surge of SARS-CoV-2 infections within the dog population amid the second wave of the pandemic. Noticeably seroprevalence of SARS-CoV-2 in the dog and the human population did not differ at the end of the study period. Male sex, breed and age were identified as significant risk factors. This study gives strong evidence that while acute dog infections are mostly asymptomatic, they can pose a significant risk to dog health. Due to the retrospective nature of this study, samples for viral isolation and PCR were unavailable. Still, seropositive dogs had a 1.97 times greater risk for developing central nervous symptoms.  相似文献   
5.
OBJECTIVES: To present the prevalence of dental caries in postwar Bosnia and Herzegovina (BH). METHODS: A survey focused on dmft and DMFT indices was carried out in four cantons of the Federation of BH in 1997. The dental health of 6- and 12-year-olds was assessed in random samples (n = 238 and 318, respectively). DMFT index in adult population was assessed in clients coming to dental offices in the same area (35-44-year-olds; n = 401). All the subjects were clinically investigated. RESULTS: During the 1991-95 war, all four cantons were affected by the migration of population. The population per dentist ratio considerably increased in three cantons. In 6-year-olds, the average dmft (+/-SD) was 4.9 +/- 4.0, and 86% of the children were affected with dental caries. The average DMFT of 12-year-olds was 6.2 +/- 3.9. On the average, 94% of the 12-year-olds were affected with dental caries. Mean DMFT of adult clients was 15.1 +/- 7.0. Almost every adult (98%) was affected with dental caries. CONCLUSIONS: The dental status in postwar BH is rather poor and the mean DMFT in all investigated age groups may be considered high. The detrimental effect of 1991-95 war on social conditions and the health care system should be considered in explaining such poor dental health. Despite the limitations, the presented data may be used to assess the treatment needs, assure the visibility for dental issues in BH, and help the west European countries to plan dental services for refugees from BH.  相似文献   
6.
Correlation of tumor-cell growth in four semisolid systems   总被引:1,自引:0,他引:1  
The correlation of the colony growth of cells disaggregated from human melanoma, sarcoma, lung, and ovarian carcinomas were studied in four different semisolid tissue culture assays: (a) the soft agar assay of Pluznik and Sachs; (b) the soft agar assay of Hamburger and Salmon; (c) the soft agar-methyl cellulose assay of Buick et al.; and (d) the methyl cellulose assay of Ogawa et al. There was no colony growth of tumor cells achieved in 15 of 15 cases assayed in Ogawa's methyl cellulose assay. The plating efficiency of the above mentioned tumors was similar in the assays of Pluznik and Sachs, Hamburger and Salmon, and Buick et al. However, the tumor take rate differed among these three systems. The assay of Buick et al. appears potentially useful for analysis of the biology of human tumors.  相似文献   
7.
Summary The reactivity of D-14 monoclonal antibody (mAb) to a specific epitope of carcinoembryonic antigen (CEA) was evaluated on formalin-fixed, paraffin-embedded tissues. A total of 52 normal tissues, 90 colorectal carcinomas and 127 non-colorectal neoplasms were tested using the peroxidase/antiperoxidase technique. D-14 mAb did not react with normal tissues apart from producing a weak staining of normal colonic glands immediately adjacent to the neoplastic structures. All 61 primary and 29 metastatic colorectal carcinomas expressed the carcinoembryonic antigen. However, there was considerable heterogeneity in cellular antigen expression in both primary and metastatic colorectal carcinomas with 10%–99% of tumor cells staining. Of 22 stomach adenocarcinomas, 14 were also immunoreactive, as were 2 of 5 pancreatic carcinomas. Only 6 of 100 neoplasms of non-gastrointestinal origin expressed weak to moderate immunoreactivity. In 7 cases, colorectal micrometastases not recognized in conventional hematoxylin and eosin slides could be identified with D-14 mAb. The specificity of this antibody could be used in differentiating colorectal carcinomas from other types of tumors, including adenocarcinoma from other sites.This paper was presented at the 1989 Annual Meeting of the American Association for Cancer Research Inc., San Francisco, California  相似文献   
8.
Abstract

Background/Objectives: Heterotopic ossification (HO) is a frequent, irreversible complication afterspinal cord injury (SCI). The objective of this article is to explain the etiology of HO; present new advances in prevention, diagnosis, and management of this complication; and provide a suggested algorithm for clinical management.

Etiology: Although still hypothetical, trauma and overexpression of bone morphogenic protein(s) in traumatized soft tissue appear to play important roles as initiating factors of HO.

Prevention: Preventive use of nonsteroidal antiinflammatory agents (NSAIDs) reduces the incidence of HO by a magnitude of 2 to 3.

Management: Early determination of serum creatine phosphokinase may have a diagnostic value in predicting the onset and severity of HO, and an NSAID may be added to etidronate therapy in the initial inflammatory phase of HO formation until C-reactive protein Ieveis return to normal range. Surgery is indicated in a subset of patients, and a regimenthat includes radiation therapy may prevent postoperative recurrence.

Conclusion: Significant progress has been made in the early prevention and management of HO. Further studies are needed to elucidate the etiology.  相似文献   
9.
BACKGROUND/OBJECTIVE: Formation of heterotopic ossification (HO) in soft tissue after spinal cord injury (SCI) is associated with various degrees of inflammation. Recent studies have shown that inhibition of inflammatory reaction with nonsteroidal anti-inflammatory drugs is an effective prevention of HO after SCI. The goal of this study was to monitor the activity of the most widely used indicators of acute inflammation--namely, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)--in patients with HO. METHODS: In a retrospective study, the results of 37 patients with HO were evaluated. There were 25 patients with tetraplegia and 12 with paraplegia. The age (mean +/- SD) of the patients was 28 +/- 8 years (range = 19-46 years). The patients were admitted to the rehabilitation center 2 to 5 weeks after SCI. HO was confirmed by bone scintigraphy. Blood samples were obtained from the patients at the time of diagnosis of HO and during the therapy. ESR was measured with the Westergren method, and serum CRP was determined by enzyme-linked immunosorbent assay. RESULTS: In the acute stage of HO, both tests were elevated in all patients. In the later stages when clinical signs and symptoms of inflammation were resolving, both tests showed a gradual decline. When clinical signs and symptoms of inflammation (fever, acute soft tissue swelling, and erythema) were not present, the concentration of CRP was normal in 91.2% of patients, whereas only 17.6% of patients had normal ESR. Mean serum concentrations of CRP were 8.9 +/- 5.6 mg/L in the inflammatory phase and 0.9 +/- 0.6 mg/L in the noninflammatory phase. CONCLUSION: The data indicate that serum CRP is a useful and more specific test than is ESR for monitoring the inflammatory activity of HO after SCI. The normalization of CRP was seen during the first 3 to 4 weeks of etidronate therapy, indicating a resolution of acute-phase inflammatory reaction.  相似文献   
10.
Congenital sacrococcygeal teratoma SCT is the most common germ cell tumor of infancy and childhood with a female preponderance. Most SCTs are diagnosed at birth, are benign, and consist of fully differentiated, mature tissues. Tumorigenesis of SCTs remains poorly understood. Almost nothing is known about possible oncogene activation or tumor suppressor inactivation in these rare tumors. We describe the presence of various oncoproteins and tumor suppressor proteins in eight cases of congenital SCT. The following oncogenes were examined: ras family c-H-, c-N-, and c-K-ras , early genes fos, jun , and tumor suppressor genes p53 and nm23-H-1 . There was no relationship between the intensity of expression of these oncoproteins and tumor suppressor genes and the following parameters: tumor size, age, and survival of the patients. We did not observe any difference, however, between the expression of the examined oncogenes and tumor suppressor genes nm23 and p53 in immature and mature teratomas. Our findings suggest that the ras family of oncogenes, fos and jun oncogenes, and nm23 and p53 tumor suppressor genes are present in congenital SCT, indicating a possible role in genesis and development of these tumors.  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