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   1068篇
  免费   56篇
  国内免费   8篇
耳鼻咽喉   5篇
儿科学   17篇
妇产科学   20篇
基础医学   106篇
口腔科学   20篇
临床医学   101篇
内科学   280篇
皮肤病学   29篇
神经病学   63篇
特种医学   38篇
外科学   187篇
综合类   20篇
预防医学   39篇
眼科学   6篇
药学   69篇
中国医学   14篇
肿瘤学   118篇
  2023年   8篇
  2022年   20篇
  2021年   27篇
  2020年   31篇
  2019年   24篇
  2018年   33篇
  2017年   22篇
  2016年   26篇
  2015年   20篇
  2014年   35篇
  2013年   39篇
  2012年   69篇
  2011年   74篇
  2010年   42篇
  2009年   47篇
  2008年   67篇
  2007年   62篇
  2006年   65篇
  2005年   55篇
  2004年   63篇
  2003年   53篇
  2002年   43篇
  2001年   12篇
  2000年   22篇
  1999年   23篇
  1998年   14篇
  1997年   6篇
  1996年   6篇
  1995年   13篇
  1994年   7篇
  1993年   16篇
  1992年   10篇
  1991年   8篇
  1990年   8篇
  1989年   8篇
  1988年   6篇
  1987年   5篇
  1986年   5篇
  1985年   5篇
  1984年   5篇
  1982年   4篇
  1981年   4篇
  1977年   3篇
  1974年   2篇
  1972年   2篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1966年   3篇
排序方式: 共有1132条查询结果,搜索用时 31 毫秒
991.
Published reports have indicated that prodromal angina before acute myocardial infarction (AMI) is associated with better outcomes and that nicorandil has cardioprotective effects on ischemic hearts. We compared cardioprotective effects of intravenous nicorandil with preconditioning effects by prodromal angina in patients with AMI who underwent percutaneous coronary intervention (PCI). In total, 368 patients with first ST-elevation AMI who underwent PCI were randomly assigned to receive nicorandil 12 mg or a placebo intravenously just before PCI. Subjects were assigned to 1 of 4 groups: 52 patients with prodromal angina were given placebo, 129 patients without prodromal angina were given nicorandil, 56 patients with prodromal angina were given nicorandil, and 131 patients without prodromal angina were given placebo. Coronary microvascular impairment after PCI was prevented at similar frequencies in groups with prodromal angina and groups on nicorandil. Five-year rates for freedom from major cardiac events were similar across groups with prodromal angina given placebo, without prodromal angina given nicorandil, and with prodromal angina given nicorandil (92.3%, 93.8%, and 92.9%, respectively) but were significantly lower in the group without prodromal angina given placebo (80.2%, p = 0.0019, 0.044, and 0.042, respectively). In conclusion, intravenous administration of nicorandil before PCI exerts pharmacologic cardioprotective effects similar to ischemic preconditioning in patients with AMI.  相似文献   
992.
993.
Objective Hepatitis C virus (HCV) eradication is associated with decreased serum ferritin and increased serum low-density lipoprotein-cholesterol (LDL-C) levels, although the mechanisms underlying these changes remain unclear. This study aimed to identify the mechanisms underlying the changes in iron and lipid metabolism after HCV eradication. Methods We retrospectively investigated iron and lipid metabolism changes in 22 patients with chronic hepatitis or compensated liver cirrhosis with HCV genotype 1b infection after HCV eradication. We measured the serum erythroferrone (ERFE) levels to assess the association with these metabolic changes. Patients were administered ledipasvir 90 mg and sofosbuvir 400 mg once daily for 12 weeks and were observed for 12 more weeks to evaluate the sustained virological response. Results Half of the patients were men. At baseline, the serum ferritin and ERFE levels were elevated, while the serum LDL-C levels were within the normal range. All patients achieved a sustained virological response at 24 weeks; furthermore, the serum ferritin and ERFE levels were significantly decreased, and the serum LDL-C levels were significantly increased at 24 weeks from baseline (p<0.001, all). In men, a decrease in serum ERFE levels was correlated with changes in the serum ferritin and LDL-C levels (r=0.78, p<0.01; r=-0.76, p<0.01, respectively). In addition, a decrease in the serum ferritin levels was correlated with an increase in the serum LDL-C levels (r=-0.89, p<0.001). These correlations were not observed in women. Conclusion Our results suggest a possible association between iron and lipid metabolism changes and the involvement of ERFE after HCV eradication in men as well as potential sex-related differences.  相似文献   
994.
995.
ObjectiveCancer cells have characteristics, such as high telomerase activity and high levels of migration activity and proliferation, which are very similar to those of germ cell lineages. In this study, we examined the expression of VASA, a germ cell lineage specific marker and evaluated its clinical significance in epithelial ovarian cancer (EOC).MethodsWe investigated VASA expression in 75 EOC tissues by immunohistochemistry, correlating results with clinicopathological factors. To clarify the effects of VASA on cellular phenotypes, we compared the protein expression profiles between SKOV-3 cells stably expressing VASA (SKOV-3-VASA) and vector-control cell lines by coupling 2D fingerprinting and identification of proteins by mass spectrometry.ResultsVASA expression in tumor cells was found in 21of 75 cases and was positively correlated with high age and serous histology. Significant down-regulation of 14-3-3σ was observed in SKOV-3-VASA versus control cells. Over-expression of VASA abrogates the G2 checkpoint, induced by DNA damage, by down-regulating the expression of 14-3-3σ.ConclusionsThese results suggest that VASA may either play a direct role in the progression of EOC or serve as a valuable marker of tumorigenesis.  相似文献   
996.
Objective Real-world data of adalimumab (ADA) in the treatment of ulcerative colitis (UC) are scarce. We aimed to study the ADA response rates and predictors of response in UC treatment. Methods This observational, prospective and multi-center study assessed the clinical outcome of refractory UC patients treated with ADA who previously had an inadequate response to either conventional therapies or other anti-TNF antibodies or tacrolimus. The primary endpoint was the proportion of UC patients achieving a clinical response and remission at 8 and 52 weeks. We also evaluated the parameters which were associated with a clinical response at 8 and 52 weeks. Results A total of 35 patients were enrolled from 11 centers. The clinical responses at 8 and 52 weeks were 60.0% and 51.4%, respectively. The clinical remission rates at 8 and 52 weeks were 45.7% and 48.6%, respectively. Positive predictors for week 52 response were combination of ADA with immunomodulator (IM) (OR: 27.229; 95% CI; 1.897-390.76; p=0.015) and a week 8 lower partial Mayo score (OR: 0.406; 95% CI; 0.204-0.809; p=0.010). A receiver operation characteristic curve analysis revealed the optimal week 8 partial Mayo score to be 2.5, therefore a partial Mayo score of ≤2 was a positive predictor for the continuation of ADA. No malignancy or death occurred during this study. Conclusion ADA was effective for inducing and maintaining both a clinical response and remission in patients with refractory UC. It remains possible that the concomitant use of IM and a week 8 partial Mayo score of ≤2 may predict the long-term response of ADA.  相似文献   
997.
Partially hydrolyzed formula (pHF) containing low lactose and probiotics may benefit the gastrointestinal health of infants. We aimed to assess the effects of pHF on mild gastrointestinal disorders (MGDs) of infants. In this single-armed trial, 80 full-term infants with MGDs were enrolled and fed a pHF for 14 consecutive days. The primary outcome resulted from the scores of gastrointestinal symptoms reported by parents using a validated Infant Gastrointestinal Symptom Questionnaire (IGSQ) at Day 0 (baseline), Day 7, and Day 14. The total IGSQ scores ranged from 13 to 65. Higher scores indicated worse gastrointestinal symptoms. The IGSQ scores (mean ± SD) decreased from Day 0 (36.0 ± 5.7) to Day 7 (28.7 ± 7.4) and Day 14 (26.5 ± 8.1 (p < 0.001), with corresponding digestive distress prevalence (IGSQ score > 30) decreasing from 87.5% to 35.0% and 28.8% (p < 0.001). In the first three days, vomiting and flatulence scores decreased at Day 1 versus Day 0, and the crying score decreased at Day 2, but no significant changes were observed for fussy and stool characteristics. All growth parameters increased and no parents reported adverse events. In conclusion, feeding with a pHF containing low lactose and probiotics may comfort infants with MGDs, and the comforting effect likely manifests early in the first three days of the feeding interventions. Trial registration: ClinicalTrials.gov NCT04112056  相似文献   
998.
目的探讨用可吸收缝线结扎胆囊管和胆囊血管行免钛夹腹腔镜胆囊切除术(laparoscopic cholecystectomy,LC)治疗胆囊颈部结石嵌顿无或伴急性胆囊炎的安全性及可行性。方法 2008年12月~2010年7月53例胆囊颈部结石嵌顿无或伴急性胆囊炎全麻下行三孔法LC,采用分离钳、电凝钩、吸引器显露胆囊,对胆囊肿大、张力高的病人采用胆囊底、体部穿刺、打孔减压,保持胆囊颈部完整,根据胆囊三角情况采用顺行或逆行方式切除胆囊。解剖出胆囊管和胆囊动脉,用分离钳将长约10 cm的可吸收线(强生公司Vicryl 31 mm 1/2c)送入腹腔,腹腔内打结结扎胆囊管及胆囊血管的近端,远端不结扎用电凝钩电凝直接离断。根据术中情况术后放置或不放腹腔引流管。结果 53例手术全部成功,无中转开腹,未使用超声刀、钛夹及其他种类夹子。49例顺行胆囊切除,4例逆行胆囊切除,所有病例均未行胆囊颈部切开取石。手术时间30~70min,平均42 min;术中出血量15~200 ml,平均24 ml。18例放置腹腔引流1,~6 d拔出腹腔引流管,平均1.8 d。术后住院3~7 d,平均3.5 d。53例随访1~18个月,平均7.6月,无胆管损伤、出血、胆漏和腹腔感染等并发症。结论 LC中用可吸收缝线代替钛夹或其他夹子及超声刀处理胆囊管及胆囊血管治疗胆囊颈部结石嵌顿安全、可行。  相似文献   
999.
We report the case of a 41-year-old woman with ovarian mixed germ cell tumor which was composed of polyembryoma and immature teratoma and who had high serum levels of α-fetoprotein (AFP) and human chorionic gonadotropin (hCG). By immunohistochemical methods, AFP was found in yolk sac cells of the embryoid bodies and immature hepatoid tissues, and hCG was found in giant syncytiotrophoblastic cells. She was treated with surgery followed by cisplatin-based combination chemotherapy. She is well, and her serum levels of AFP and hCG have not been elevated for more than 4 years after the treatment.  相似文献   
1000.
Cell-mediated immune response (CMIR) to both serum and purified hepatitis B antigen (HBAg) was measured in 151 subjects using the leukocyte MIF test. Ninety-five percent of patients with HBAg-positive acute viral hepatitis (AVH) and 64% of patients with HBAg-negative AVH had positive MIF tests. Positive MIF tests were rarely present in asymptomatic HBAg carriers and were not found in patients with alcoholic liver disease or in normal controls. The data suggest that many patients with AVH in whom HBAg is undetectable may have hepatitis B and that measurement ofin vitro MIF to HBAg is a sensitive index for establishing the etiological role of the antigen in the liver disease.Presented in part before the American Association for the Study of Liver Disease, Chicago, November 1, 1972.Supported in part by NIH contract NIH-NIHLI72-2951-B  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