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   193篇
  免费   4篇
儿科学   7篇
基础医学   11篇
口腔科学   1篇
临床医学   38篇
内科学   58篇
皮肤病学   9篇
神经病学   11篇
外科学   27篇
综合类   1篇
眼科学   2篇
药学   14篇
肿瘤学   18篇
  2021年   1篇
  2015年   3篇
  2014年   3篇
  2013年   1篇
  2010年   5篇
  2009年   3篇
  2007年   1篇
  2006年   9篇
  2005年   1篇
  2004年   5篇
  2003年   4篇
  2002年   2篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1998年   9篇
  1997年   13篇
  1996年   7篇
  1995年   8篇
  1994年   4篇
  1993年   7篇
  1992年   2篇
  1991年   3篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1986年   1篇
  1985年   6篇
  1984年   1篇
  1983年   2篇
  1982年   5篇
  1981年   2篇
  1980年   3篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1974年   1篇
  1971年   1篇
  1968年   2篇
  1967年   1篇
  1966年   1篇
  1959年   2篇
  1958年   3篇
  1957年   21篇
  1956年   15篇
  1955年   13篇
  1954年   12篇
排序方式: 共有197条查询结果,搜索用时 31 毫秒
41.
42.
In a series of 2,013 gastric polyps in 1,201 patients, morphological and histopathological studies have been performed. Ninety-three hyperplastic polyps in 56 patients have been followed-up endoscopically and histopathologically for five to 12 years. The incidence of detection of gastric polyps has increased: 1.4% in 1967 to 8.7% in 1979 year by year. Thirty patients (54%) among the 56 showed changes in number, size or shape of polyps during follow-up. Twenty patients (37%) revealed numerical changes (increase in 16 patients, reversion in three patients and vanishing in two patients).
Twenty-eight polyps (30%) showed morphological changes, six of them showed continuous enlargement, 18 lesions repeated enlargement, stationary or reduction stages, three lesions were reversed and two polyps disappeared.
Histopathologically, three lesions showed transformation from the hyperplastic type to adenoma while demonstrating morphological enlargement. Two of these showed increase in cellular atypia, from the hyperplastic type through adenoma with severe atypia and finally to carcinoma in the polypectomy specimens. From this study, it was concluded that although hyperplastic polyps show changes in size, shape or number with passage of time, malignant changes occur in only a few cases.  相似文献   
43.
Abstract Tonsillectomy was performed on 10 adult sleep apnea patients (five males, five females; average age, 39 years old; average body mass index, 24.8 kg/m2). Tonsillectomy alone was indicated if tonsillar hypertrophy was moderate to severe and the length of the soft palate was less than 35 mm according to cephalometry. Remarkable improvements were observed in all cases following surgery. The average weight of the resected tonsils was 11 g. The patients demonstrated a preoperative apnea + hypopnea index (AHI) of 14.4/h. This decreased to 2.9/h postoperatively. The intraesophageal pressure change improved from -36.6 to -15.7 cmH2O following surgery. A significant correlation between preoperative AHI and the degree of obesity ( r = 0.684, P < 0.05) was found. Although uvulopalatopharyngoplasty has been used extensively to treat sleep apnea, the present results suggests that certain subjects can be effectively treated through only tonsillectomy.  相似文献   
44.
Gut-associated lymphoid tissue is the major inductive site of the mucosal immune system, which is functionally independent of the systemic immune system. Both the amount and type of dietary fat modulate intestinal immune function. Absorption of long-chain fatty acids stimulates lymphocyte flux and lymphocyte blastogenesis in intestinal lymphatics. Long-chain fatty acid absorption also significantly enhances migration of T lymphocytes to Peyer's patches, possibly due to up-regulation of adhesion molecules, such as α4-integrin and L-selectin. Lipoproteins are involved in stimulation of lymphocyte function by both receptor-dependent and independent mechanisms. However, unsaturated fatty acids at higher concentrations have a suppressive effect on cell-mediated immunity via eicosanoid release, receptor affinity changes or interactions with intracellular signal transduction. Fat absorption also influences various other cells in the intestinal mucosa: increased cytokine release from intestinal epithelial cells follows long-chain fatty acid absorption. In Crohn's disease, elemental diets and total parenteral nutrition often induce remission, possibly by reducing antigenic load on activated immune cells in the intestine and, thus, down-regulating hyperreactive CD4 cells. Dietary oleic acid supplements caused an immunological reversal effect in the intestinal immune system of animals fed an elemental diet. An excess of long-chain fatty acids in an elemental diet, therefore, may negate its beneficial effect on gut-associated lymphoid tissues in Crohn's disease. In contrast, supplemental dietary fish oil apparently tends to prevent relapse of Crohn's disease. Because dietary fat intake is closely associated with immunological function of the intestinal mucosa, careful manipulation of dietary fat can be important in management of this disease.  相似文献   
45.
A novel fat absorption test to clarify the malabsorption syndrome was developed using a micronephelometric technique and compared with the classic conventional technique using 131I-triolein. An integrity of time-sequential light scattered from chylomicron-related turbidity in serum was determined between 0 and 300 min after butter fat load, being expressed in terms of the light scattering intensity (LSI). A good correlation was obtained between LSI and the serum level of chylomicron-triglyceride determined by an ultracentrifugation technique (r=0.819, P < 0.001). The maximal LSI was consistently observed at 180 min after administration of a test meal in the normal group (n= 39), whereas the malabsorption syndrome group (n= 35) was distinctly different and could be further classified according to four patterns of LSI changes. In addition, an inverse correlation was found between this fat absorption test and the 131I-triolein absorption test. It was concluded that the micronephelometric technique which does not use a radionuclide is advantageous in its simple and safe evaluation of fat malabsorption syndrome.  相似文献   
46.
Cystic hamartoma of the renal pelvis is a rare benign tumor in the same category as mixed epithelial and stromal tumors. We present a 33-year-old woman with a solid and cystic intrarenal tumor extending into the renal pelvis. She underwent radical nephrectomy and ureterectomy under the diagnosis of renal tumor or renal pelvic tumor. Histopathologically, the tumor was composed of a biphasic proliferation of epithelial and mesenchymal elements. We believe the present case is best classified as a cystic hamartoma of the renal pelvis in the category of mixed epithelial and stromal tumors because of the coexistence of hamartomatous lesions, such as the proliferation of adipose cells and well to poorly differentiated fibromuscular lesions.  相似文献   
47.
We evaluated the clinical usefulness of a protein induced by vitamin K absence, antagonist-prothrombin (PIVKA-II), in detecting hepatocellular carcinoma (HCC) specifically in patients with liver cirrhosis, and the possible correlation between levels of PIVKA-II and pathological features of HCC. Plasma levels of PIVKA-II and alpha-fetoprotein (AFP) were measured in 628 patients with various diseases, including 253 with liver cirrhosis and 116 with HCC. PIVKA-II was detected (greater than or equal to 0.1 arbitrary unit/mL) in 54.3% of HCC and the concentration showed a positive correlation with the tumour size. As a screening test for the detection of HCC, PIVKA-II produced values comparable with those of AFP with a sensitivity, specificity and validity of 52.8, 98.8 and 51.6% respectively. Sixteen of 45 patients (37%) with HCC who had low AFP (less than 100 ng/mL) levels were positive for PIVKA-II. No apparent relationship, however, could be found between the levels of PIVKA-II and the aetiology or pathological findings of HCC. These results suggest that PIVKA-II can be a reliable marker for detecting HCC in patients with liver cirrhosis.  相似文献   
48.
Twenty-four community residing elderly people in need of care, who were registered with the municipal welfare center in Miyagi Prefecture, Japan, and their principal caregivers participated in the study. The principal caregivers completed a self-administered questionnaire involving their demographic status, provided data on their utilization of formal services and completed the Center for Epidemiologic Studies Depression Scale (CES-D). The health visitors examined the activities of daily living (ADL) and mental status of these 24 elderly individuals. More than half the caregivers appeared to be depressed. The non-depressed caregivers used significantly more services than the depressed caregivers even after the caregivers' age was statistically controlled.  相似文献   
49.
叉头框c2在中轴骨骼发育过程中的作用   总被引:1,自引:1,他引:1  
目的:研究叉头框-c2(Foxc2)基因在中轴骨骼发育过程中的作用。方法:通过制作Foxc2基因无效突变小鼠,分析Foxc2基因缺损鼠中轴骨骼的发育异常。结果:在骨成形蛋白-2(BMP-2)处理的肌胚细胞C2C12中Foxc2蛋白显著增高,以及碱性磷酸酶和骨钙蛋白也显著地增高。15只敲除Foxc2基因的纯合子仔鼠均表现出正中腭裂,听骨和脊椎发育不良以及面部前后距发育不良。结论:这些结果表明,Foxc2在由衍生于中胚层和神经嵴细胞形成骨骼的过程中有不可代替的作用。  相似文献   
50.
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