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   49959篇
  免费   3508篇
  国内免费   1424篇
耳鼻咽喉   385篇
儿科学   1656篇
妇产科学   1685篇
基础医学   5263篇
口腔科学   1546篇
临床医学   7561篇
内科学   5862篇
皮肤病学   608篇
神经病学   2199篇
特种医学   2350篇
外国民族医学   20篇
外科学   3473篇
综合类   10886篇
现状与发展   11篇
一般理论   2篇
预防医学   3157篇
眼科学   1069篇
药学   2251篇
  79篇
中国医学   1375篇
肿瘤学   3453篇
  2024年   72篇
  2023年   627篇
  2022年   1044篇
  2021年   1903篇
  2020年   2052篇
  2019年   1470篇
  2018年   1427篇
  2017年   1497篇
  2016年   1879篇
  2015年   1648篇
  2014年   3116篇
  2013年   3234篇
  2012年   2854篇
  2011年   3075篇
  2010年   2493篇
  2009年   2445篇
  2008年   2351篇
  2007年   2628篇
  2006年   2467篇
  2005年   2175篇
  2004年   1937篇
  2003年   1703篇
  2002年   1401篇
  2001年   1287篇
  2000年   956篇
  1999年   821篇
  1998年   708篇
  1997年   690篇
  1996年   619篇
  1995年   553篇
  1994年   500篇
  1993年   448篇
  1992年   370篇
  1991年   352篇
  1990年   299篇
  1989年   243篇
  1988年   281篇
  1987年   236篇
  1986年   184篇
  1985年   184篇
  1984年   115篇
  1983年   78篇
  1982年   92篇
  1981年   81篇
  1980年   75篇
  1979年   62篇
  1978年   41篇
  1977年   24篇
  1976年   27篇
  1975年   29篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
本文报告用间接免疫荧光法检测特异性IgG抗体对流行性出血热的诊断意义。53例不同病期的出血热患者的血清,其间接荧光抗体的阳性率为49/53(占92.45%)。有77.36%的患者血清,检出IgG抗体的时间是在发病后的1~2周。血清中IgG的滴度与疾病的严重性无密切相关。另25例非EHF患者,其血清特异性IgG抗体均为阴性。可见检测特异性IgG抗体对EHF的诊断颇为有用。  相似文献   
102.
Objective: To study the diagnostic value of T2^*-weighted first-pass perfusion imaging in breast tumors. Methods: We analyzed the magnetic resonance imaging (MRI) information along with the pathological and immunohistochemistry results. Magnetic resonance imaging was performed in 28 patients with breast tumor. The time to signal intensity curves were generated according to the T2^*-weighted first-pass perfusion imaging. The curve's maximal signal intensity drop rate and maximal signal intensity decrease time were analyzed and compared with the pathological diagnoses after surgery. Results: Malignant breast lesions showed higher maximal signal intensity drop rate (44.69% ± 17.07 vs. 17.22% ±7.49, P 〈 0.001) than benign lesions, but there was no significant difference of maximal signal decrease time between those two lesions (23.94 s ± 4.92 vs. 20.02 s ± 6.83, P 〉 0.05). Conclusion: The T2^*-weighted first-pass perfusion imaging has enough sensitivity and specificity in breast tumor diagnosis.  相似文献   
103.
心血管疾病并发焦虑抑郁症状2050例心理干预治疗分析   总被引:13,自引:1,他引:12  
目的:了解心血管疾病并发焦虑抑郁症状的情况并探讨心理干预等对焦虑抑郁症状的影响。方法:对住院的2050例心血管疾病并发焦虑抑郁症状的患者进行回顾性分析。结果:心血管疾病患者中并发有焦虑抑郁症状者占56%;其常表现为类似心绞痛、左心衰竭症状,可并发有心律失常;高血压病并发有焦虑抑郁患者对血压升高的耐受性差,动态血压检查以非勺型改变者居多;单纯使用心血管药物治疗效果欠佳,心理干预,焦虑抑郁症状严重者结合抗焦虑抑郁药物疗效显著。结论:心血管疾病患者常并发焦虑抑郁症状,心理干预治疗等可有效改善患者的症状。  相似文献   
104.
本文报道用二维超声心动图对主动脉瓣关闭不全124例进行病变鉴别诊断。就其图象特征结合X线所见,心音图等进行了鉴别诊断的探讨。其中,有风湿性心脏病111例;感染性心内膜炎4例;冠状动脉粥样硬化性心脏病5例;马凡氏综合征2例;左室假腱索2例。认为此项检查对主动脉瓣关闭不全病变鉴别诊断有一定的价值。  相似文献   
105.
The clinical and ultrasonographic (US) features of 15 cases of mesenteric or omental cyst are herein described. This series included seven male and eight female patients, whose age ranged from 2–89 years. Correct clinical diagnosis was made in two children only, but preoperative US examination accurately demonstrated the lesion in 11 of 13 patients (85%). These cystic lesions usually had a thin wall, internal septations, and fluid content with sedimentation. Enteric duplication cysts had a relatively thick wall merging with the muscle layer of bowel loop, and multiloculation was noted mainly with cystic lymphangiomas or pseudocysts. The diagnostic and surgical management of these lesions are briefly reviewed and their US appearance is illustrated.  相似文献   
106.
AIM: To undertake a systematic review of the diagnostic performance of clinical examination, sample acquisition and sample analysis in infected foot ulcers in diabetes. METHODS: Nineteen electronic databases plus other sources were searched. To be included, studies had to fulfil the following criteria: (i) compare a method of clinical assessment, sample collection or sample analysis with a reference standard; (ii) recruit diabetic individuals with foot ulcers; (ii) present 2 x 2 diagnostic data. Studies were critically appraised using a 12-item checklist. RESULTS: Three eligible studies were identified, one each on clinical examination, sample collection and sample analysis. For all three, study groups were heterogeneous with respect to wound type and a small proportion of participants had foot ulcers due to diabetes. No studies identified an optimum reference standard. Other methodological problems included non-blind interpretation of tests and the time lag between index and reference tests. Individual signs or symptoms of infection did not prove to be useful tests when assessed against punch biopsy as the reference standard. The wound swab did not perform well when assessed against tissue biopsy. Semiquantitative analysis of wound swab might be a useful alternative to quantitative analysis. The limitations of these findings and their impact on recommendations from relevant clinical guidelines are discussed. CONCLUSION: Given the importance of this topic, it is surprising that only three eligible studies were identified. It was not possible to describe the optimal methods of diagnosing infection in diabetic patients with foot ulceration from the evidence identified in this systematic review.  相似文献   
107.
瘤性体液中肿瘤血管生长因子的提取和检测   总被引:1,自引:0,他引:1  
《肿瘤防治杂志》2005,12(17):1289-1291
  相似文献   
108.
The objective of this study is to determine whether a normal fetal morphology ultrasound scan in women older than 35 years reduces the risk of aneuploidy. We reviewed the results of amniocentesis and second trimester sonogram in all women older than 35 years from 1991 to 1995. None had prior screening. We excluded fetuses with structural anomalies. We determined the sensitivity and specificity of minor markers in detecting Down syndrome and also determined the reduction in risk of a normal sonogram. Among the 2060 women older than 35 years giving birth during the study period, 16 (0.78%) delivered an infant with Down syndrome. Of the 16 fetuses, two had no prenatal testing or ultrasound, two had invasive testing but no second trimester sonogram, five had a normal sonogram and seven had one or more sonographic markers of Down syndrome. At least 17% of women older than 35 years did not participate in prenatal testing or ultrasound. Ultrasound detected Down syndrome with a sensitivity of 59% (95% confidence interval: 45–72%), a false‐positive rate of 10.6% (9.4–11.8%) and a positive predictor value of 1 in 9. The likelihood of having normal karyotype if the sonogram was normal was 0.46 (0.31–0.61). In women older than 35 years, a normal second trimester sonogram reduces the risk of Down syndrome by more than 50%. At least 17% of women older than 35 years do not participate in prenatal testing or ultrasound.  相似文献   
109.
目的探讨HBeAg阳性与阴性慢性乙型肝炎(慢乙肝)患者中医辨证及其相关指标的相关性。方法对226例慢乙肝患者进行中医辨证分型,检测乙肝两对半、乙肝病毒DNA定量和肝功能、肝纤维化指标。结果各证型的乙型肝炎病毒(HBV)水平呈一定规律性,肝郁脾虚型>肝肾阴虚型>湿热中阻型>脾肾阳虚型>瘀血阻络型,随着病情的活动、病程的推延,HBV水平逐渐下降。无论HBeAg阳性与阴性,慢乙肝患者肝郁脾虚、肝肾阴虚、脾肾阳虚、瘀血阻络各型与湿热中阻型相比肝功能和肝纤维化指标均存在显著性差异。结论各证型的HBV水平呈一定规律性,提示病毒滴度与中医病因病机的转化有一定关系。湿热中阻和瘀血阻络是肝纤维化的关键。  相似文献   
110.
目的 评价诊断中老年男子部分雄激素缺乏综合征(PADAM)的游离睾酮指数(FTI).方法 对129例45岁以上健康男性的FTI进行年龄相关分析.以推算的游离睾酮(CFT)值为依据,对FTI进行有效性检验.结果 男子在中老年期FTI与增龄呈明显的负相关.FTI敏感性97.78%,特异性58.33%.结论 计算简单的FTI可用于PADAM病人的筛选和随访,尤其对70岁以上男子是血清FT较为有效的参数.  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