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   367篇
  免费   28篇
  国内免费   2篇
耳鼻咽喉   5篇
儿科学   25篇
妇产科学   13篇
基础医学   57篇
口腔科学   5篇
临床医学   31篇
内科学   70篇
皮肤病学   7篇
神经病学   28篇
特种医学   2篇
外科学   47篇
综合类   2篇
预防医学   28篇
眼科学   14篇
药学   28篇
中国医学   2篇
肿瘤学   33篇
  2023年   3篇
  2022年   15篇
  2021年   14篇
  2020年   17篇
  2019年   26篇
  2018年   22篇
  2017年   16篇
  2016年   18篇
  2015年   9篇
  2014年   22篇
  2013年   24篇
  2012年   23篇
  2011年   30篇
  2010年   22篇
  2009年   11篇
  2008年   29篇
  2007年   26篇
  2006年   13篇
  2005年   13篇
  2004年   14篇
  2003年   12篇
  2002年   11篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1998年   2篇
  1996年   2篇
排序方式: 共有397条查询结果,搜索用时 31 毫秒
21.
BACKGROUND: Needle localization breast biopsy (NLBB) is the standard for removal of breast lesions after vacuum assisted core biopsy (VACB). Disadvantages include a miss rate of 0% to 22%, a positive margin rate of approximately 50%, and vasovagal reactions (approximately 20%). We hypothesized that clip migration after VACB is clinically significant and may contribute to the positive margin rates seen after NLBB. METHODS: We performed a retrospective review of postbiopsy films in patients who had undergone VACB with stereotactic clip placement for abnormal mammograms. We measured the distance between the clip and the biopsy site in standard two view mammograms. The location of the biopsy air pocket was confirmed using the prebiopsy calcification site. The Pythagorean Theorem was used to calculate the distance the clip moved within the breast. Pathology reports on NLBB or intraoperative hematoma-directed ultrasound-guided breast biopsy (HUG, which localizes by US the VACB site) were reviewed to assess margin status. RESULTS: In all, 165 postbiopsy mammograms on patients who had VACB with clip placement were reviewed. In 93 evaluable cases, the mean distance the clip moved was 13.5 mm +/- 1.6 mm, SEM (95% CI = 10.3 mm to 16.7 mm). Range of migration was 0 to 78.3 mm. The median was 9.5 mm. In 21.5% of patients the clip was more than 20 mm from the targeted site. Migration of the clip did not change with the age of the patient, the size of the breast or location within the breast. In the subgroup of patients with cancer, margin positivity (including those with close margins) after NLBB was 60% versus 0% in the HUG group. CONCLUSIONS: Significant clip migration after VACB may contribute to the high positive margin status of standard NLBBs. Surgeons cannot rely on needle localization of the clip alone and must be cognizant of potential clip migration. HUG as an alternative biopsy technique after VACB eliminates operator dependency on clip location and may have superior results in margin status.  相似文献   
22.
BACKGROUND: Determining the extent of infiltrating lobular carcinoma (ILCA) in the breast is difficult. This study was designed to determine if the size of ILCA on magnetic resonance imaging (MRI) correlated with final pathology. METHODS: Retrospective study of patients between 1998 and 2004, who were evaluated for extent of ILCA prior to definitive treatment, was conducted. Demographic data and radiology and pathology results were obtained. Spearman correlation coefficient was used. RESULTS: Twenty-nine patients (median age 62 years) had MRI of breast. Fourteen patients (48%) had contralateral MRIs; 13 (45%) normal; 1 (8%) prompted core biopsy; 6 of 13 patients underwent contralateral mastectomies, which were benign. The distribution of tumor size was: T1 = 15 (52%); T2 = 7 (24%); T3 = 5 (17%); T4 = 2 (7%). Spearman correlation coefficient between tumor size on ultrasound and MRI with pathology was .19 (P = .5) and .88 (P < .001), respectively. CONCLUSION: MRI provided superior correlation between tumor size and pathology.  相似文献   
23.
Disseminated BCG infection is a rare complication of vaccination that occurs in patients with impaired immunity. In recent years, a series of inherited disorders of the IL-12-IFN- axis have been described that predispose affected individuals to disseminated disease caused by BCG, environmental Mycobacteria, and non-typhoidal Salmonella. The routine immunological work-up of these patients is normal and the diagnosis requires specific investigation of the IL-12-IFN- circuit. We report here the first two such patients originating from and living in Iran. The first child is two years old and suffers from complete IFN- receptor 2 deficiency and disseminated BCG infection. He is currently in clinical remission thanks to prolonged multiple antibiotic therapy. The other, a 28-year-old adult, suffers from IL-12p40 deficiency and presented with disseminated BCG infection followed by recurrent episodes of systemic salmonellosis. He is now doing well. A third patient of Iranian descent, living in North America, was reported elsewhere to suffer from IL-12R1 deficiency. These three patients thus indicate that various inherited defects of the IL-12-IFN- circuit can be found in Iranian people. In conclusion we recommend to consider the disorders of the IL-12-IFN- circuit in all patients with severe BCG infection, disseminated environmental mycobacterial disease, or systemic non-typhoidal salmonellosis, regardless of their ethnic origin and country of residence.  相似文献   
24.
25.
Rats fed a saturated fat diet are protected from experimentally induced alcoholic liver disease, but the molecular mechanisms underlying this phenomenon remain in dispute. We fed male Sprague-Dawley rats intragastrically by total enteral nutrition using diets with or without ethanol. In 1 control and 1 ethanol group, the dietary fat was corn oil at a level of 45% of total energy. In other groups, saturated fat [18:82 ratio of beef tallow:medium-chain triglyceride (MCT) oil] was substituted for corn oil at levels of 10, 20, and 30% of total energy, while keeping the total energy from fat at 45%. After 70 d, liver pathology, serum alanine aminotransferase (ALT), biochemical markers of oxidative stress, liver fatty acid composition, cytochrome P450 2E1 (CYP2E1) expression and activity and cytochrome P450 4A (CYP4A) expression were assessed. In rats fed the corn oil plus ethanol diet, hepatotoxicity was accompanied by oxidative stress. As dietary saturated fat content increased, all measures of hepatic pathology and oxidative stress were progressively reduced, including steatosis (P < 0.05). Thus, saturated fat protected rats from alcoholic liver disease in a dose-responsive fashion. Changes in dietary fat composition did not alter ethanol metabolism or CYP2E1 induction, but hepatic CYP4A levels increased markedly in rats fed the saturated fat diet. Dietary saturated fat also decreased liver triglyceride, PUFA, and total FFA concentrations (P < 0.05). Increases in dietary saturated fat increased liver membrane resistance to oxidative stress. In addition, reduced alcoholic steatosis was associated with reduced fatty acid synthesis in combination with increased CYP4A-catalyzed fatty acid oxidation and effects on lipid export. These findings may be important in the nutritional management and treatment of alcoholic liver disease.  相似文献   
26.
Membrane transport systems active in cellular inorganic phosphate (P(i)) acquisition play a key role in maintaining cellular P(i) homeostasis, independent of whether the cell is a unicellular microorganism or is contained in the tissue of a higher eukaryotic organism. Since unicellular eukaryotes such as yeast interact directly with the nutritious environment, regulation of P(i) transport is maintained solely by transduction of nutrient signals across the plasma membrane. The individual yeast cell thus recognizes nutrients that can act as both signals and sustenance. The present review provides an overview of P(i) acquisition via the plasma membrane P(i) transporters of Saccharomyces cerevisiae and the regulation of internal P(i) stores under the prevailing P(i) status.  相似文献   
27.
BACKGROUND: Sentinel lymph node biopsy (SLNB) is deemed suitable only for unifocal breast cancers since multiple foci of cancers may drain to different nodes. We hypothesized that subareolar injection (SI) could identify the sentinel lymph nodes (SLN) accurately in patients with multiple cancers (MC) in the breast. METHODS: We prospectively employed SI of lymphazurin or technetium sulfur colloid, or both, for the identification of SLN in patients with MC in the breast. All patients underwent axillary dissection to compute the accuracy of SLNB. RESULTS: Forty patients presented with MC in the same breast between January 1996 and July 2002. Fifty-two percent (21 of 40) of patients had involvement of more than 1 quadrant; 18% (7 of 40) had more than 1 histologic type of cancers. SLNs were successfully identified in 100% of patients. Axillary disease was present in 63% (25 of 40) of patients. Sensitivity of SLNB was 100% and false negative rate was 0%. The SLN was the only node involved in 45% (18 of 40) of patients. CONCLUSIONS: SLNB using the SI technique may be an alternative to complete axillary dissection in patients with multiple breast cancers.  相似文献   
28.

Background  

Different surgical techniques have been developed for the gastrojejunostomy (GJS) in laparoscopic Roux-en-Y gastric bypass (LRYGBP) with the anastomosis performed in a circular-stapled, linear-stapled, or totally hand-sewn way. No technique seems superior to the other as no consistent data on weight loss or complication rates were described.  相似文献   
29.
IntroductionHypovitaminosis D which is a frequent problem in overweight and obese individuals, seems to interfere with cells responsible for control of glycemic status. Therefore, the current research intended to study the impact of supplementation with vitamin D on insulin homeostasis among healthy obese and overweight individuals.MethodsThe current study was conducted among obese or overweight individuals who had hypovitaminosis D. After separation of participants into two groups, one group received vitamin D pearls (50,000 IU/weekly) for eight weeks, whereas another group received a placebo over the same period. Next, the level of vitamin D, fasting blood sugar (FBS), fasting insulin, Homeostasis Model Assessment 2 for Insulin Resistance (HOMA2-IR), Function of β-cell (HOMA2-β), and Insulin Sensitivity (HOMA2-S) and lipid profile of participants were evaluated.ResultsOverall, 67.2% of the participants were female. No considerable difference was observed concerning biochemical parameters among the study groups at baseline. After eight weeks, the mean (SD) level of vitamin D was significantly lower in the placebo group than those in the vitamin D group. (38.6 ± 8.1 vs. 14.9 ± 6.4; P < 0.001). The patients who received vitamin D had significant lower levels of FBS (P < 0.001), fasting insulin (P < 0.001), HOMA2-IR (P < 0.001), and HOMA2-β (P = 0.03), than the placebo group. The HOMA2-S was significantly enhanced in vitamin D group, while it reduced in another group (P < 0.001). However, no considerable decrease was found in triglyceride, cholesterol, high-density lipoprotein or low-density lipoprotein.ConclusionSupplementation with vitamin D improved sensitivity to insulin and pancreatic function of β cells of healthy overweight and obese adults.  相似文献   
30.
Comparing lymphocyte responses to allergenic and nonallergenic foods could reveal the differences between pathogenic and normal immune responses to foods. Defining the cytokine-producing phenotypes of peanut-specific lymphocytes from peanut-allergic children, children who outgrew peanut allergy, and children who have always tolerated peanuts may be useful for understanding the mechanisms of food tolerance. Investigating immune responses against foods is hindered, however, by the fact that circulating food antigen-specific lymphocytes are very rare. In a novel approach we used carboxyfluorescein succinimidyl ester to detect peanut-specific lymphocytes by flow cytometry. We confirmed that these cells are indeed peanut specific by cloning. Peanut-allergic donors show Th2 polarization of cytokine production by peanut-specific cells (IFN-gamma (low), TNF-alpha (low), IL-4 (high), IL-5 (high), IL-13 (high)). Conversely, nonallergic children and children who have outgrown their allergy show Th1 skewing to peanut antigens (IFN-gamma(high), TNF-alpha (high), IL-4 (low), IL-5 (low), IL-13(low)), similarly to nonallergenic food antigens (beta-lactoglobulin, OVA). This finding suggests that peanut antigens do not intrinsically induce Th2 skewing, but that the type of response depends upon the donor's allergic status. In conclusion, food allergic status is characterized by a Th2 response whereas Th1-skewed responses underlie oral tolerance.  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