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   56058篇
  免费   4920篇
  国内免费   3314篇
耳鼻咽喉   542篇
儿科学   543篇
妇产科学   647篇
基础医学   7201篇
口腔科学   1146篇
临床医学   6894篇
内科学   8744篇
皮肤病学   760篇
神经病学   2998篇
特种医学   2500篇
外国民族医学   37篇
外科学   6251篇
综合类   7883篇
现状与发展   7篇
一般理论   2篇
预防医学   3472篇
眼科学   1560篇
药学   5553篇
  45篇
中国医学   2731篇
肿瘤学   4776篇
  2024年   150篇
  2023年   794篇
  2022年   2192篇
  2021年   2933篇
  2020年   1949篇
  2019年   1836篇
  2018年   1968篇
  2017年   1686篇
  2016年   1803篇
  2015年   2617篇
  2014年   3245篇
  2013年   2929篇
  2012年   4655篇
  2011年   4743篇
  2010年   3039篇
  2009年   2479篇
  2008年   3216篇
  2007年   3083篇
  2006年   2854篇
  2005年   2601篇
  2004年   1881篇
  2003年   1726篇
  2002年   1522篇
  2001年   1225篇
  2000年   1244篇
  1999年   1183篇
  1998年   652篇
  1997年   693篇
  1996年   547篇
  1995年   457篇
  1994年   367篇
  1993年   262篇
  1992年   342篇
  1991年   253篇
  1990年   219篇
  1989年   192篇
  1988年   150篇
  1987年   136篇
  1986年   107篇
  1985年   91篇
  1984年   51篇
  1983年   50篇
  1982年   22篇
  1981年   25篇
  1980年   13篇
  1979年   23篇
  1978年   11篇
  1973年   11篇
  1971年   9篇
  1969年   10篇
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
81.
BACKGROUND: Haptoglobin polymorphism is associated with the prevalence of infections, autoimmune diseases, cardiovascular diseases, and other disorders. Congenital haptoglobin deficiency is associated with anaphylactic transfusion reactions in anhaptoglobinaemic patients with antihaptoglobin antibody. AIMS: To investigate haptoglobin genotypic distribution (including the Hp(0) allele) and associated serum haptoglobin concentrations in Koreans. METHODS: Five hundred and nine healthy Korean adults were randomly selected. Two methods were used: haptoglobin genotyping based on a polymerase chain reaction (PCR) system that exploited the structural difference of the Hp(1) and Hp(2 )alleles, and another PCR method that detected haptoglobin gene deletion by amplification of the junctional region of the Hp(0) allele. Serum haptoglobin concentrations were measured by nephelometry. RESULTS: The haptoglobin genotypes of 509 subjects were as follows: Hp(1)Hp(1), 7.1%; Hp(2)Hp(1), 37.7%; Hp(2)Hp(2), 49.3%; Hp(0)Hp(1), 2.2%; Hp(0)Hp(2), 3.5%; Hp(0)Hp(0), 0.2%. The gene frequency of Hp(0) in Koreans was calculated to be 0.031. Significant differences were seen among the concentrations of each haptoglobin genotype (Kruskal-Wallis test). Hp(0)Hp(2), but not Hp(0)Hp(1), was associated with hypohaptoglobinaemia. CONCLUSIONS: PCR methods for differentiating between haptoglobin genotypes, including the Hp(0) allele, may be useful in a broad spectrum of basic studies and clinical examinations.  相似文献   
82.
Intraductal papillary mucinous tumor (IPMT) of the pancreas, a lesion consisting of mucin-producing cells with neoplastic potential, is characterized by duct ectasia, mucin hypersecretion, often extensive papillary intraductal growth, varying degrees of cytologic atypia, and relatively indolent growth. The clinical presentation of IPMT of the pancreas is characterized by chronic or recurrent attacks of abdominal discomfort often in association with low level pancreatic enzyme elevations. Less commonly these lesions may be detected as asymptomatic radiographic abnormalities. Interestingly, a case of a minute IPMT (2 mm in height and 7 mm in length, adenoma) in the main pancreatic duct presenting with acute pancreatitis in a 55 year-old man has been reported in the Japanese literature. Recently, we also experienced a case of a minute IPMT in a branch pancreatic duct causing repeated bouts of acute pancreatitis in a 75 year-old man. A filling defect at the neck of the main pancreatic duct seen on an endoscopic retrograde pancreatogram performed after recovery of the second attack of acute pancreatitis led the patient to undergo an exploratory laparotomy. After a near-total pancreatectomy was carried out, a minute (3 x 7 mm) IPMT of borderline malignancy was discovered in a branch duct at the head portion near the pancreatic neck without any lesions in the main pancreatic duct. Surprisingly, despite the resective surgery the patient died of carcinomatosis 8.5 months after the operation. We herein report a case of a minute but aggressive IPMT of the pancreas with a review of the literature.  相似文献   
83.
84.
PurposeDissection after plain balloon angioplasty is required to achieve adequate luminal area; however, it is associated with a high risk of vascular events. This study aimed to examine the relationship between non-flow limiting coronary dissections and subsequent lumen loss and long-term clinical outcomes following successful drug-coated balloon (DCB) treatment of de novo coronary lesions.Materials and MethodsA total of 227 patients with good distal flow (Thrombolysis in Myocardial Infarction flow grade 3) following DCB treatment were retrospectively enrolled and stratified according to the presence or absence of a non-flow limiting dissection. The primary endpoint was late lumen loss (LLL) at 6-month angiography, and the secondary endpoint was target vessel failure (TVF, a composite of cardiac death, target vessel myocardial infarction, target vessel revascularization, and target vessel thrombosis).ResultsThe cohort consisted of 95 patients with and 132 patients without a dissection. There were no between-group differences in LLL (90.8%) returning for angiography at 6 months (0.05±0.19 mm in non-dissection and 0.05±0.30 mm in dissection group, p=0.886) or in TVF (6.8% in non-dissection and 8.4% in dissection group, p=0.799) at a median follow-up of 3.4 years. In a multivariate analysis, the presence of dissection and its severity were not associated with LLL or TVF. Almost dissections (93.9%) were completely healed, and there was no newly developed dissection at 6-month angiography.ConclusionThe presence of a dissection following successful DCB treatment of a de novo coronary lesion may not be associated with an increased risk of LLL or TVF (Impact of Drug-coated Balloon Treatment in de Novo Coronary Lesion; NCT04619277).  相似文献   
85.
Metabolic syndrome is a worldwide health problem, and obesity is closely related to type 2 diabetes, cardiovascular disease, hypertension, and cancer. According to WHO in 2018, the prevalence of obesity in 2016 tripled compared to 1975. D. morbifera reduces bad cholesterol and triglycerides levels in the blood and provides various antioxidant nutrients and germicidal sub-stances, as well as selenium, which helps to remove active oxygen. Moreover, D. morbifera is useful for treating cardiovascular diseases, hypertension, hyperlipidemia, and diabetes. Therefore, we study in vivo efficacy of D. morbifera to investigate the prevention effect of obesity and cholesterol. The weight and body fat were effectively reduced by D. morbifera water (DLW) extract administration to high-fat diet-fed C57BL/6 mice compared to those of control mice. The group treated with DLW 500 mg∙kg−1∙d−1 had significantly lower body weights compared to the control group. In addition, High-density lipoprotein (HDL) cholesterol increased in the group treated with DLW 500 mg∙kg−1∙d−1. The effect of DLW on the serum lipid profile could be helpful to prevent obesity. DLW suppresses lipid formation in adipocytes and decreases body fat. In conclusion, DLW can be applied to develop anti-obesity functional foods and other products to reduce body fat.  相似文献   
86.
87.
88.
以硅酸钠、氯化铁为原料制备聚硅氯化铁(简称PFSC)混凝剂。重点考察Fe/SiO2摩尔比对PFSC混凝效果的影响。结果表明:PFSC的混凝效果优于聚硅酸(PS),且Fe/SiO2摩尔比对PFSC的混凝效果有较大的影响。确定Fe/SiO2摩尔比为1:1.5时,其混凝效果最佳,且用药量少而范围广。为制备高效的PFSC提供了优化条件。  相似文献   
89.
(1)目的 总结320例胆管术后,经T管窦道纤维胆管镜治疗残余结石的经验。(2)方法 对320例胆管术后残余结石病人行纤维胆管镜取石,分析其临床表现并予以随访。(3)结果 结石取净287例,失败33例,(4)结论 纤维胆管镜对于术后胆管残余结石的治疗起着重要作用。  相似文献   
90.
目的为探讨咽旁间隙肿瘤的诊断与治疗.方法报告28例咽旁间隙肿瘤的临床资料.结果良性肿瘤24例,其中神经源性肿瘤10例,涎腺混合瘤9例,其它5例;恶性肿瘤4例.全部病例均行手术治疗.结论颈侧切开为一较好的手术径路.  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