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   280篇
  免费   17篇
  国内免费   11篇
耳鼻咽喉   1篇
儿科学   16篇
妇产科学   7篇
基础医学   46篇
临床医学   27篇
内科学   53篇
神经病学   6篇
特种医学   3篇
外科学   34篇
综合类   16篇
预防医学   18篇
眼科学   26篇
药学   31篇
  1篇
中国医学   4篇
肿瘤学   19篇
  2024年   1篇
  2023年   4篇
  2022年   5篇
  2021年   8篇
  2020年   10篇
  2019年   6篇
  2018年   10篇
  2017年   7篇
  2016年   10篇
  2015年   15篇
  2014年   14篇
  2013年   24篇
  2012年   23篇
  2011年   14篇
  2010年   7篇
  2009年   6篇
  2008年   20篇
  2007年   14篇
  2006年   15篇
  2005年   15篇
  2004年   18篇
  2003年   10篇
  2002年   4篇
  2001年   7篇
  2000年   3篇
  1999年   4篇
  1998年   2篇
  1997年   2篇
  1995年   6篇
  1994年   3篇
  1993年   1篇
  1992年   5篇
  1991年   3篇
  1990年   3篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1974年   1篇
  1968年   1篇
  1965年   1篇
排序方式: 共有308条查询结果,搜索用时 0 毫秒
81.
Effects of procaine on dibutyryl adenosine 3',5'-cyclic monophosphate ((Bu)2cAMP)-, Ca2(+)- or forskolin-induced steroidogenesis were examined in isolated bovine adrenocortical cells. Procaine (less than 1.0 mM) caused a marked suppression of (Bu)2cAMP- or forskolin-induced steroidogenesis in the absence of extracellular Ca2+, but did not affect on Ca2(+)-induced steroidogenesis in the cells. (Bu)2cAMP decreased the cell associated 45Ca2+. However, procaine (300 microM) inhibited this effect of (Bu)2cAMP. These results suggest that procaine may abolish (Bu)2cAMP-induced Ca2+ release from intracellular calcium store(s) and inhibits steroidogenesis.  相似文献   
82.
PPARgamma is a dominant regulator of fat cell differentiation. However, this nuclear receptor also plays an important role in the differentiation of intestinal and other epithelial cell types. The mechanism by which PPARgamma can influence the differentiation of such diverse cell lineages is unknown. We show here that PPARgamma interacts with Hic-5, a coactivator protein expressed in gut epithelial cells. Hic-5 and PPARgamma colocalize to the villus epithelium of the small intestine, and their expression during embryonic gut development correlates with the transition from endoderm to a specialized epithelium; expression of both these factors is reduced in tumors. Forced expression of Hic-5 in colon cancer cells enhances the PPARgamma-mediated induction of several gut epithelial differentiation/maturation markers such as L-FABP, kruppel-like factor 4 (KLF4), and keratin 20. siRNA directed against Hic-5 specifically reduces PPARgamma-mediated induction of gut epithelial genes in colon cells and in an ex vivo model of embryonic gut differentiation. Finally, forced expression of Hic-5 during 3T3-L1 preadipocyte differentiation inhibits adipogenesis while inducing inappropriate expression of several mRNAs characteristic of gut epithelium in these mesenchymal cells. These results indicate that Hic5 is an important component in determining an epithelial differentiation program induced by PPARgamma.  相似文献   
83.
ONJECTIVES: A standard rodent diet for space flight must meet the unique conditions imposed by the space environment and must be nutritionally adequate because diet can influence the outcome of experiments. We evaluated the use of National Aeronautics and Space Administration (NASA) Foodbars as a standard space flight diet for rats. METHODS: The Foodbar's semi-purified formulation permitted criteria such as nutrient consistency, high nutrient bioavailability, and flexibility of formulation to be met. Extrusion of the semi-purified diet produced Foodbars with the proper texture and a non-crumbing solid form for use in space. Treatment of Foodbar with 0.1% potassium sorbate prevented mold growth. Irradiation (15 to 25 kGy) prevented bacterial growth and, in combination with sorbate treatment, added protection against mold for shelf stability. RESULTS: During the development process, nutrient analyses indicated that extrusion and irradiation produces nutrient losses. Nutrients were adjusted accordingly to compensate for processing losses. Nutrient analysis of Foodbars continues to be performed routinely to monitor nutrient levels. It is important that the standard rodent diet provide nutrients that will prevent deficiency but also avoid excess that may mask physiologic changes produced by space flight. All vitamin levels in the Foodbars, except for vitamin K, conformed to or exceeded the current National Research Council (NRC) 1995 recommendations. All indispensable amino acids in Foodbar conformed to or exceeded the NRC nutrient recommendation for mouse growth and rat maintenance. However, some indispensable amino acids were slightly below recommendations for rat reproduction and growth. Short-term (18 to 20 d) animal feeding studies indicated that Foodbars are palatable, support growth, and maintain health in rats. CONCLUSIONS: Results indicated that NASA Rodent Foodbars meet the physical and nutritional criteria required to support rodents in the space environment and thus may be used successfully as a standard diet for short-term space flight studies. However, the nutritional adequacy of NASA Rodent Foodbars as a standard diet on longer-duration (>20 d) space flight missions remains to be determined.  相似文献   
84.
Phlebosclerotic colitis coincident with carcinoma in adenoma   总被引:1,自引:0,他引:1  
Phlebosclerosis of the colon is a rare disease characterized by a thickening of the wall of the colon with fibrosis, hyalinization and calcification to the affected veins. These symptoms result in a type of ischemic colitis known as phlebosclerotic colitis. A case of phlebosclerotic colitis coincident with carcinoma in adenoma is reported. A 74-year-old Japanese woman was admitted to hospital because of a mass in her right lower abdomen. Abdominal computed tomography examination revealed linear calcifications in the wall of the cecum and the ascending colon. Colonoscopy revealed dark purple mucosa with multiple ulcers in the cecum and the ascending colon. Biopsy specimens showed a marked hyalinous thickening of the wall of small blood vessels in the mucosa. Phlebosclerotic colitis was suspected because of negative results with amyloid stain. Alternative ileocolic angiography showed the serpentine of the peripheral nature blood vessels and pooling at the late venous phase. Microscopic examination of the surgically resected colon revealed mucosal and submucosal fibrosis, and a thickening of the venous wall with fibrosis, hyalinization and calcification from the mucosa to the serosa, which caused a marked luminal narrowing. A small polypoid lesion was also found in the affected region and was diagnosed histologically as carcinoma in adenoma. To our knowledge, this is the first reported case of phlebosclerotic colitis complicated by carcinoma.  相似文献   
85.
Female Sprague–Dawley rats provide an animal model for studying the role of nutrition in renal health due to their sensitivity to diet-induced alterations in kidney function. Nephrocalcinosis, a common renal abnormality found in rats, has been implicated in subsequent renal failure. Simple dietary manipulations, such as changing the source of dietary protein, may influence nephrocalcinosis. This study evaluates the consumption of krill protein concentrate (KPC), a novel and high-quality protein, on renal and bone health. Young female Sprague–Dawley rats (n = 10/group) were individually housed in metabolic cages and fed ad libitum diets consisting of 10% crude protein supplied as KPC or casein for 4 weeks. Diets were isocaloric, isonitrogenous, and matched for calcium (Ca) and phosphorus (P). Urinary n-acetyl glucosaminidase (NAG) was measured and kidney histology performed to assess kidney damage. Biomarkers of kidney function were determined by calorimetric assays. Ca and P balance and bone concentrations were measured using inductively coupled plasma mass spectrometry. Femoral strength was determined by three-point bend testing. Rats fed KPC had lower (P = 0.005) urinary NAG levels and minimal microtubular Ca deposition compared to rats fed casein. There was a tendency (P < 0.06) for higher glomerular filtration rates and lower proteinuria, and higher (P = 0.03) urinary output in rats fed KPC compared to casein. There were no differences in Ca and P balance or bone measurements of total bone mineral content, Ca, P or strength between rats fed KPC and casein. Based on the study results, KPC prevented early renal injury leading to nephrocalcinosis and potential bone loss.  相似文献   
86.
Cancer testis (CT) antigens are attractive targets for cancer immunotherapy because their expression is restricted in normal germ line tissues but frequently detected in variety of tumors. OY-TES-1 is identified as a member of CT antigens. Current knowledge about OY-TES-1 expression in colorectal cancer (CRC) is solely based on mRNA analysis. None of previous researches has studied OY-TES-1 at protein level. In this study, OY-TES-1 polyclonal antibody was generated. The expression of OY-TES-1 mRNA and protein was detected by RT-PCR and immunohistochemistry in 60 CRC and paired adjacent non-tumor tissues, 24 colorectal adenoma and 3 normal colon tissues, respectively. Sera from 73 CRC patients were also tested for OY-TES-1 antibody by ELISA. Our results showed that the frequency of OY-TES-1 mRNA expression was statistically higher in CRC (73.3%, 44/60) than that in adjacent non-tumor tissue (55.0%, 33/60) and colorectal adenoma (45.8%, 11/24). For the first time, OY-TES-1 protein expression was found in (43.3%, 26/60) of CRC tissues, but absent in any of adjacent non-tumor and colorectal adenoma tissues. No OY-TES-1 expression was found in normal colon by either RT-PCR or immunohistochemistry. Furthermore, OY-TES-1 protein expression was correlated with tumor invasion stage (P=0.004) and histological grade (P=0.040). Anti-OY-TES-1 antibody was detected in (9.6%, 7/73) of CRC patients’ sera but not in 76 healthy donors. This finding demonstrates that OY-TES-1 is frequently expressed in CRC and is able to induce humoral immune response spontaneously in CRC patients, suggesting that it might be a promising immunotherapy target for CRC.  相似文献   
87.

Background

Congenital duodenal obstruction (CDO) is one of the most common anomalies in newborns, and accounting for nearly half of all cases of neonatal intestinal obstruction. This study aimed to review our single-center experience in managing congenital duodenal obstruction while evaluate the outcomes.

Methods

We conducted a retrospective analysis of the records of all neonates dianogsed with congenital duodenal obstruction admitted to our center between January 2003 and December 2012. We analyzed demographic criteria, clinical manifestations, associated anomalies, radiologic findings, surgical methods, postoperative complications, and final outcomes.

Results

The study comprised 287 newborns (193 boys and 94 girls). Birth weight ranged from 950 g to 4850 g. Fifty-three patients were born prematurely between 28 and 36 weeks’ gestation. Malrotation was diagnosed in 174 patients, annular pancreas in 66, duodenal web in 55, duodenal atresia or stenosis in 9, preduodenal portal vein in 2, and congenital band compression in 1. Twenty patients had various combinations of these conditions. Presenting symptoms included bilious vomiting, dehydration, and weight loss. X-rays of the upper abdomen demonstrated the presence of a typical double-bubble sign or air-fluid levels in 68.64% of patients, and confirmatory upper and/or lower gastrointestinal contrast studies were obtained in 64.11%. Multiple associated abnormalities were observed in 50.52% of the patients. Various surgical approaches were used, including Ladd’s procedure, duodenoplasty, duodenoduodenostomy, duodenojejunostomy, or a combination of these. Seventeen patients died postoperatively and 14 required re-operation.

Conclusions

Congenital duodenal obstruction is a complex entity with various etiologies and often includes multiple concomitant disorders. Timely diagnosis and aggressive surgery are key to improving prognosis. Care should be taken to address all of the causes of duodenal obstruction and/or associated alimentary tract anomalies during surgery.  相似文献   
88.
IntroductionThe authors carried out a retrospective assessment of the efficacy of CryoMaze procedure employed between early 2004 and June 2011 jointly with performing other cardiac surgeries in patients suffering permanent/persistent or paroxysmal Atrial Fibrillation (AF) and other supraventricular arrhythmias. Included in the set to be assessed were 383 patients. This paper aims to assess the effectiveness of the procedure in maintaining the Sinus Rhythm (SR).MethodsWithin one year following the discharge from the Center, the patients, then outpatients, underwent four follow-up checks – data obtained in the checks have been used to compile this assessment.ConclusionOne year after the CryoMaze therapy was given, 74% of the patients exhibited sinus rhythm. No complications attributable to the use of cryoenergy were observed. The best results in restoring and maintaining the sinus rhythm were achieved in the group of patients indicated for CryoMaze because of their paroxysmal atrial fibrillation.  相似文献   
89.
目的:探讨术前玻璃体腔注射曲安奈德对微创玻璃体切割术治疗脉络膜脱离型视网膜脱离的临床疗效.方法:选择我院2015-01/2016-06临床确诊的脉络膜脱离型视网膜脱离患者23例23眼,入院后先行玻璃体腔内注射曲安奈德4~5 d后行23 G玻璃体切割和硅油填充术.观察手术前后视力、眼压情况,以及术后视网膜复位率和并发症情况.随诊6~9 mo.结果:曲安奈德注射后前房反应均减轻,眼压升高,由入院眼压4.02±1.47mmHg升高到术前13.69±4.68mmHg,术后升高到17.72±5.88mmHg,入院时眼压与术前和术后比较,差异均有统计学意义(P<0.05).患者术后末次随访视力较术前均有所改善,视力术后≥0.3者9眼(39%),术后≥0.05者18眼(78%).术后1wk,1、3mo和末次随访矫正视力与术前比较,差异均有统计学意义(P<0.05).视网膜复位情况:手术后2 wk有23眼(100%)全视网膜在位,一次视网膜解剖复位率87%,二次视网膜解剖复位率100%.术后1 mo时3眼出现下方视网膜局限性脱离,经二次手术巩膜外垫压后视网膜复位.无眼内出血、医源性视网膜裂孔、眼内感染、晶状体损伤等并发症.术后一过性高眼压7眼,均出现在术后12~14d,减少局部激素滴眼液使用和点用降眼压滴眼液后,眼压控制在正常范围.结论:术前玻璃体腔注射曲安奈德进行预手术处理,能够提高微创玻璃体切割术治疗脉络膜脱离型视网膜脱离的疗效,降低手术难度,提高视力,避免了全身使用激素的副作用.  相似文献   
90.
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