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   51篇
  免费   10篇
耳鼻咽喉   3篇
儿科学   3篇
基础医学   8篇
临床医学   7篇
内科学   12篇
神经病学   7篇
特种医学   1篇
外科学   12篇
眼科学   1篇
药学   1篇
肿瘤学   6篇
  2022年   2篇
  2021年   4篇
  2020年   1篇
  2019年   2篇
  2018年   1篇
  2017年   3篇
  2016年   2篇
  2015年   1篇
  2014年   2篇
  2013年   2篇
  2012年   4篇
  2011年   3篇
  2010年   1篇
  2009年   2篇
  2008年   4篇
  2007年   2篇
  2006年   3篇
  2005年   2篇
  2004年   5篇
  2003年   4篇
  2002年   3篇
  2000年   2篇
  1998年   3篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
排序方式: 共有61条查询结果,搜索用时 0 毫秒
51.
The restriction fragment length polymorphism of c-Ha-ras-1 and L-myc genes and expression of cell surface effector molecules were studied to determine their potential utility as markers for assessing risk of metastasis in 84 lung cancer patients. We performed a comparative study of primary lung carcinomas, metastases, adjacent tissues and blood samples in a group of patients with lung cancer of different histological types, grade of differentiation and presence of regional and distant metastasis. No differences in the frequency of c-Ha-ras-1 rare alleles were found between lung cancer patients and unaffected controls. The detection of common a4-allele seems to be associated with metastasis and low differentiation of lung carcinomas. S-allele of L-myc was observed in 82.6% of patients with metastatic lesions. Homozygosity of L-allele patients was not evidence for distant metastasis and only 17.4% of these patients have metastatic lesions of the lymph nodes. The expression of HLA class I and receptor of transferrin (TrRec) were tested immunohistochemically in the same patients. In the group of squamous cell carcinomas with regional metastases the expression of HLA class I antigens was decreased [7/21 (33.3%) positive staining tumors versus 13/20 (65.0%) in the group without metastases]. The opposite situation was observed for TrRec. The data of restriction fragment length polymorphism of oncogenes and expression of two cell surface effector molecules, identified in the same patients, were combined. The registration of more than one poor marker, tested in individuals with squamous cell carcinoma, closely correlated with dissemination and advanced stage of the disease. Nearly 90% (20/22) of patients with well and moderately differentiated tumor revealed metastatic lesions versus 6.6% (1/15) of patients with manifestation of a single poor marker. Finally, proposals could be made for the development of a risk group that incorporates both clinical and molecular biology features in the prediction of metastasis.  相似文献   
52.
Despite numerous attractive intracellular targets, protein therapeutics have been principally confined to the extracellular space due to the lack of a straightforward way to deliver functional polypeptides to the cell interior. Peptide sequences facilitating intracellular protein delivery have been identified; however, current strategies to apply them require problematic steps, such as generation of new in-frame fusion proteins, covalent chemical conjugation, and denaturation. We have developed a new approach to protein transfer into cells and tissues that relies on single-step decoration by cysteine-flanked, arginine-rich transporter peptides. This approach facilitated cell and tissue delivery of a variety of functional proteins, including antibodies and enzymes. Decoration with transporter peptides thus provides an attractive general means of intracellular delivery of functional proteins in vitro and in tissue.  相似文献   
53.
Muir-Torre-like syndrome in Fhit-deficient mice   总被引:17,自引:0,他引:17       下载免费PDF全文
To investigate the role of the Fhit gene in carcinogen induction of neoplasia, we have inactivated one Fhit allele in mouse embryonic stem cells and produced (129/SvJ x C57BL/6J) F(1) mice with a Fhit allele inactivated (+/-). Fhit +/+ and +/- mice were treated intragastrically with nitrosomethylbenzylamine and observed for 10 wk posttreatment. A total of 25% of the +/+ mice developed adenoma or papilloma of the forestomach, whereas 100% of the +/- mice developed multiple tumors that were a mixture of adenomas, squamous papillomas, invasive carcinomas of the forestomach, as well as tumors of sebaceous glands. The visceral and sebaceous tumors, which lacked Fhit protein, were similar to those characteristic of Muir-Torre familial cancer syndrome.  相似文献   
54.
The tumor suppressor gene FHIT encompasses the common human chromosomal fragile site at 3p14.2 and numerous cancer cell biallelic deletions. To study Fhit function we cloned and characterized FHIT genes from Drosophila melanogaster and Caenorhabditis elegans. Both genes code for fusion proteins in which the Fhit domain is fused with a novel domain showing homology to bacterial and plant nitrilases; the D. melanogaster fusion protein exhibited diadenosine triphosphate (ApppA) hydrolase activity expected of an authentic Fhit homolog. In human and mouse, the nitrilase homologs and Fhit are encoded by two different genes: FHIT and NIT1, localized on chromosomes 3 and 1 in human, and 14 and 1 in mouse, respectively. We cloned and characterized human and murine NIT1 genes and determined their exon-intron structure, patterns of expression, and alternative processing of their mRNAs. The tissue specificity of expression of murine Fhit and Nit1 genes was nearly identical. Because fusion proteins with dual or triple enzymatic activities have been found to carry out specific steps in a given biochemical or biosynthetic pathway, we postulate that Fhit and Nit1 likewise collaborate in a biochemical or cellular pathway in mammalian cells.  相似文献   
55.
The present study describes a local drug delivery system with two functions, which can suppress tumor growth and accelerate wound healing. Thе system consists of a two-layer multicomponent fibrin-based gel (MCPFTG). The internal layer of MCPFTG, which is in direct contact with the wound surface, contains cisplatin placed on a CultiSpher-S collagen microcarrier. The external layer of MCPFTG consists of a CultiSpher-S microcarrier with lyophilized bone marrow stem cells (BMSCs). The efficacy of MCPFTG was evaluated in a rat model of squamous cell carcinoma of the tongue created with 4-nitroquinoline 1-oxide. The results of the study showed that, within 20–25 days, a non-healing wound of the tongue was formed in animals that underwent only 85% resection of squamous cell carcinoma, while rapid progression of the residual tumor was concomitantly observed. Immunohistochemical methods revealed high expression of cyclin D1 and low expression of E-cadherin in these animals. Additionally, high expression of p63 and Ki-67 was noted. In 80% of animals with squamous cell carcinoma of the tongue that were treated with MCPFTG after 85% tumor resection, a noticeable suppression of tumor growth was evident throughout 150 days, and tumor recurrence was not detected. Immunohistochemistry revealed low or moderate expression of cyclin D1, and high expression of E-cadherin throughout the whole observation period. The MCPFTG-based local drug delivery system was shown to be effective in suppressing tumor growth and preventing recurrence. MCPFTG decreased the toxicity of cisplatin and enhanced its antitumor activity. In addition, lyophilized paracrine BMSC factors present in MCPFTG accelerated wound healing after tumor removal. Thus, the present study suggests novel opportunities for the development of a multifunctional drug delivery system for the treatment of squamous cell carcinoma.  相似文献   
56.
57.
58.

BACKGROUND AND PURPOSE

Blood–brain barrier (BBB) disruption detected on magnetic resonance imaging (MRI) in acute ischemic stroke as a hyperintense acute reperfusion marker (HARM) is associated with upregulation of matrix metalloproteinase‐9 (MMP‐9). Although activated leukocytes, including monocytes, are the main source of MMPs, limited data exist to support relationship between leukocyte activation and BBB disruption in patients with acute ischemic stroke. The goal of this study is to investigate the relationship between neutrophils, lymphocytes, and monocytes with BBB disruption detected as HARM (+) in patients with acute ischemic stroke.

METHODS

We conducted a retrospective analysis of prospectively collected data in patients who did not receive any reperfusion therapy with acute (<12 hours) ischemic stroke. MRI scans were obtained at baseline, 24 hours, and 5 days. HARM was evaluated on the 24‐hour follow‐up scan.

RESULTS

Thirty‐three patients were studied. HARM was detected in 27% of patients. Median volumes of baseline perfusion (mean transit time [MTT]) deficit (219.4 mL vs. 158.4 mL, P = .029) and DWI infarct growth at 24 hours (18.50 mL vs. .14 mL, P = .017), as well as the median absolute numbers (1 × 103/mm3) of monocytes, were significantly higher in HARM (+) versus HARM (?) patients (0.9 vs. 0.6, p = 0.011).

CONCLUSION

Increased monocyte count associated with HARM supports importance of systemic inflammation in BBB disruption in acute ischemic stroke.  相似文献   
59.
BACKGROUND: Dedicated minimally invasive surgery suites are available that contain specialized equipment to facilitate endoscopic surgery. Laparoscopy performed in a general operating room is hampered by the multitude of additional equipment that must be transported into the room. The objective of this study was to compare the preparation times between procedures performed in traditional operating rooms versus dedicated minimally invasive surgery suites to see whether operating room efficiency is improved in the specialized room. METHODS: The records of 50 patients who underwent laparoscopic procedures between September 2000 and April 2002 were retrospectively reviewed. Twenty-three patients underwent surgery in a general operating room and 18 patients in an minimally invasive surgery suite. Nine patients were excluded because of cystoscopic procedures undergone prior to laparoscopy. Various time points were recorded from which various time intervals were derived, such as preanesthesia time, anesthesia induction time, and total preparation time. A 2-tailed, unpaired Student t test was used for statistical analysis. RESULTS: The mean preanesthesia time was significantly faster in the minimally invasive surgery suite (12.2 minutes) compared with that in the traditional operating room (17.8 minutes) (P=0.013). Mean anesthesia induction time in the minimally invasive surgery suite (47.5 minutes) was similar to time in the traditional operating room (45.7 minutes) (P=0.734). The average total preparation time for the minimally invasive surgery suite (59.6 minutes) was not significantly faster than that in the general operating room (63.5 minutes) (P=0.481). CONCLUSION: The amount of time that elapses between the patient entering the room and anesthesia induction is statically shorter in a dedicated minimally invasive surgery suite. Laparoscopic surgery is performed more efficiently in a dedicated minimally invasive surgery suite versus a traditional operating room.  相似文献   
60.
PURPOSE: To evaluate anterior segment retinoblastoma with high-frequency ultrasound. DESIGN: Interventional case report. METHODS: An 11-year-old boy with a total retinal detachment and multiple white anterior chamber nodules was examined with high-frequency ultrasound before enucleation of the globe. RESULTS: Multiple solid and cystic nodular tumors were found in the anterior chamber angle. With high-frequency ultrasound, tumor was discovered posterior to the iris, over the ciliary processes, and on the lens capsule. No calcifications were noted. Other findings included angle closure related to iris neovascularization and uveal thickening. CONCLUSION: High-frequency ultrasound can be used to evaluate retinoblastoma extension into the anterior segment. These images may be used for comparison in future cases of retinoblastoma with anterior chamber invasion.  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