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   211篇
  免费   15篇
  国内免费   2篇
儿科学   6篇
妇产科学   2篇
基础医学   32篇
口腔科学   3篇
临床医学   11篇
内科学   65篇
皮肤病学   2篇
神经病学   5篇
特种医学   29篇
外科学   35篇
综合类   3篇
预防医学   5篇
眼科学   3篇
药学   14篇
肿瘤学   13篇
  2021年   4篇
  2018年   2篇
  2017年   4篇
  2016年   1篇
  2015年   5篇
  2014年   1篇
  2013年   2篇
  2012年   5篇
  2011年   4篇
  2010年   4篇
  2009年   7篇
  2008年   6篇
  2007年   2篇
  2006年   5篇
  2005年   5篇
  2004年   4篇
  2003年   4篇
  2002年   3篇
  2000年   2篇
  1999年   5篇
  1998年   14篇
  1997年   15篇
  1996年   11篇
  1995年   5篇
  1994年   1篇
  1993年   1篇
  1992年   7篇
  1991年   3篇
  1990年   8篇
  1989年   12篇
  1988年   5篇
  1987年   8篇
  1986年   4篇
  1985年   8篇
  1984年   3篇
  1983年   5篇
  1981年   4篇
  1980年   2篇
  1977年   2篇
  1976年   4篇
  1975年   3篇
  1974年   3篇
  1973年   2篇
  1972年   1篇
  1971年   3篇
  1970年   6篇
  1969年   3篇
  1968年   4篇
  1967年   2篇
  1966年   2篇
排序方式: 共有228条查询结果,搜索用时 0 毫秒
1.
Forty-three solitary hyperplastic polyps removed from the colon or the rectum (HPC) were examined under light microscopy. A histochemical and immunohistochemical study was undertaken in order to evaluate semiquantitatively the nature and the distribution of epithelial mucins and the secretion of carcinoembryonic antigen (CEA). Ten HPC had a peculiar morphologic pattern (four with regenerative dysplasia and six with adenomatous foci). CEA secretion was always increased (37 per cent of cases) or highly increased (63 per cent of cases) with respect to the normal colonic mucosa. The nature and distribution of the secreted acid mucins were modified: sulfomucin was equal (25 per cent of cases) or higher (75 per cent of cases) than that in normal rectal or sigmoid colonic mucosae; sialomucin was strongly decreased in 91 per cent of cases. Some of these functional changes (CEA) are also observed in neoplastic lesions. These findings are not in accord with the hypothesis that hyperplastic polyp is a simple hyperplasia of the mucosal epithelium and suggest a disorder in cellular differentiation, particularly for the larger polyps.  相似文献   
2.
A comprehensive mutational scanning test for the p53 coding region based on multiplex PCR and two-dimensional DNA electrophoresis was designed and evaluated. In a 2-step multiplex PCR, the p53 coding region (exons 2-11) was amplified as a single 8646-bp fragment by long- distance PCR in step one. This fragment served as a template for the subsequent co-amplification of the individual exons in two multiplex groups in step two. The multiplex products were then separated, first on the basis of size in non-denaturant polyacrylamide gels and then on the basis of sequence by denaturing gradient gel electrophoresis (DGGE). Primers for optimal PCR, melting behavior and 2-D gel distribution were designed using a recently developed computer program. The resulting two-dimensional gene scanning (TDGS) test was evaluated by screening, in a blinded fashion, 29 coded DNA samples from Li- Fraumeni syndrome patients with previously identified germline mutations. All mutations were correctly detected. This assay provides an accurate, cost-effective and non-radioactive method for simultaneous mutational scanning of all p53 coding exons.   相似文献   
3.
4.
5.
6.
Diaphragmatic lesions are usually congenital bronchogenic cysts. A patient with a known diaphragmatic cyst presented with new onset right upper quadrant pain. Repeat imaging showed enlargement of the cyst, the CA19–9 cancer marker was raised at 312iu/ml (normal: <27iu/ml) and positron emission tomography combined with computed tomography showed focally increased uptake in the cystic wall. In view of symptoms and risk of neoplasia, the lesion was excised. Histology showed a benign epidermoid cyst. Features falsely suggesting neoplasia have been reported previously with benign splenic cysts but not with a benign diaphragmatic epidermoid cyst.  相似文献   
7.
8.
Cystemustine is a new nitrosourea with high anti-tumor activity and a short plasma half-life in mice. The influence of circadian dosing time upon its toxicities was first investigated in a total of 368 synchronized male B6D2F1 mice. Late survival rate varied from 4% in mice receiving a single dose of cystemustine (conventional lethal dose 50%) at 7 hours after 1ight onset (HALO) up to 88% in mice treated at 15 or at 19 HALO. Target organ toxicities (bone marrow, circulating blood cells, spleen, colon and duodenum) were studied following a single slightly lower dose of cystemustine. Leukopenia was the major hematologic effect encountered. Leukocyte count nadir occurred 7 days after injection and was lowest following cystemustine at 7 HALO as compared to 13 or 19 HALO. Recovery was faster after cystemustine at 19 HALO as compared to other dosing times. Bone-marrow necrotic lesions were more pronounced I day after cystemustine at 7 HALO than after cystemustine at 19 HALO. Thus, a large-amplitude circadian rhythm characterized the toxicity of this nitrosourea in mice. The lowest cystemustine toxicity was found near the middle of the active span of the rest-activity circadian cycle of mice. © 1996 Wiley-Liss, Inc.  相似文献   
9.
The aims of the study were to measure the collagen content in pancreas using a colorimetric method and to compare the amount of collagen in normal pancreas (11 cases), diffuse fibrosing pancreatitis (17 cases), and chronic calcifying pancreatitis (11 cases). The procedure of fibrosis measurement was based on the selective capacity of two dyes, Sirius red and fast green, to set on collagen and noncollagenous proteins, respectively. After staining of sections, colors were eluted from the sections and the specific absorbance of each eluted dye was read on a spectrophotometer. The collagen content in normal pancreata was 26.5 +/- 7.2 micrograms collagen/mg protein. The amount of collagen increased with the age of patients: the mean value of the patients under the age of 50 was 18.2 +/- 4 micrograms collagen/mg protein whereas the mean value in older patients was 31.9 +/- 8 micrograms collagen/mg protein (p less than 0.01). The value of collagen in pancreas with a diffuse fibrosing pancreatitis was 44.7 +/- 7.5 micrograms collagen/mg protein. This value was significantly different from the collagen content in normal pancreas (p less than 0.001) and in pancreas with a chronic calcifying pancreatitis (77.9 +/- 8 micrograms collagen/mg protein, p less than 0.001). This method permits discrimination between different chronic diseases that can also be differentiated on a histopathologic basis.  相似文献   
10.

Chronic granulomatous disease (CGD) is an inherited immunodeficiency due to defective leukocyte NADPH responsible for recurrent infections and aberrant inflammation. Mutations in the CYBB gene are responsible for the X-linked CGD and account for approximately 70% of the cases. CGD is diagnosed during childhood in males. Female carriers may have biased X-inactivation and may present with clinical manifestations depending on the level of residual NADPH oxidase activity. We report the case of a previously asymptomatic female carrier who was diagnosed at age 67 with a skin infection with the rare fungus Paecilomyces lilacinus as the first manifestation of CGD. Dihydrorhodamine 123 (DHR) activity was below 10%. Next-generation sequencing (NGS) revealed mutations in DNMT3A, ASXL1, and STAG2 suggesting that clonal hematopoiesis could be responsible for a progressive loss of NADPH oxidase activity and the late onset of X-linked CGD in this patient. Long-term follow-up of asymptomatic carrier women seems to be essential after 50 years old.

  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