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   4629篇
  免费   410篇
  国内免费   21篇
耳鼻咽喉   56篇
儿科学   142篇
妇产科学   66篇
基础医学   614篇
口腔科学   136篇
临床医学   448篇
内科学   816篇
皮肤病学   81篇
神经病学   443篇
特种医学   283篇
外科学   695篇
综合类   260篇
一般理论   1篇
预防医学   453篇
眼科学   76篇
药学   223篇
中国医学   40篇
肿瘤学   227篇
  2022年   45篇
  2021年   102篇
  2020年   54篇
  2019年   81篇
  2018年   82篇
  2017年   76篇
  2016年   81篇
  2015年   90篇
  2014年   130篇
  2013年   174篇
  2012年   232篇
  2011年   227篇
  2010年   162篇
  2009年   154篇
  2008年   166篇
  2007年   197篇
  2006年   218篇
  2005年   191篇
  2004年   166篇
  2003年   155篇
  2002年   135篇
  2001年   124篇
  2000年   138篇
  1999年   139篇
  1998年   92篇
  1997年   101篇
  1996年   83篇
  1995年   74篇
  1994年   58篇
  1993年   58篇
  1992年   77篇
  1991年   79篇
  1990年   81篇
  1989年   98篇
  1988年   96篇
  1987年   81篇
  1986年   79篇
  1985年   60篇
  1984年   47篇
  1983年   32篇
  1982年   36篇
  1981年   25篇
  1980年   32篇
  1979年   31篇
  1978年   34篇
  1977年   29篇
  1976年   26篇
  1974年   27篇
  1972年   24篇
  1969年   24篇
排序方式: 共有5060条查询结果,搜索用时 15 毫秒
31.
Long-chain polyunsaturated fatty acids (LCP) are thought to be required for optimal nervous system development in the newborn. A commercial milk formula containing LCP (Aptamil-LCP) with a fatty acid profile closely resembling breast milk, has recently been introduced for term infants. The absorption of fatty acids in term infants was examined in a double-blind randomized controlled trial comparing Aptamil-LCP ( n = 20) and standard Aptamil ( n = 20). Formula-fed newborn infants were studied from birth for 14 d. Fat balances (3 d) were performed from d 10. A 3-d stool collection was performed from d 10 in a parallel breastfed group ( n = 21). Plasma samples were taken on d 6. Median fat excretion (mg kg−1) was 897.1, 615.0 and 355.2 with Aptamil, Aptamil-LCP and breastfeeding, respectively. The median total fat absorption coefficient in Aptamil-LCP-fed infants was higher than in those fed standard Aptamil ( p < 0:01). These findings were accounted for by differences in the excretion and absorption of long-chain saturated fatty acids (C14:0, C16:0 and C18:0). Higher fat excretion was associated with bulkier and firmer stools. Only trace amounts of LCP were detected in the stools of all groups. This accounted for less than 4% of dietary intake in Aptamil-LCP-fed infants. No differences in the utilization of LCP from Aptamil-LCP and breast milk feeding were apparent. Plasma phospholipid fatty acid composition data reflected differences in dietary LCP intake. Thus, PL LCP levels were highest in the breastfed infants and lowest in the Aptamil-fed infants, with values for the Aptamil-LCP-fed group falling in between.  相似文献   
32.
33.
BACKGROUND: Disturbances in both attention and language are central to the phenomenology of the schizophrenia spectrum disorders. The purpose of this study was to investigate the relative contributions of two factors, family status and schizotypy, on electrophysiologic measures of attention and semantic processing in family members of individuals with schizophrenia. METHODS: Fifteen first-degree relatives of individuals with schizophrenia and 15 comparison subject controls participated in diagnostic evaluations, an assessment of schizotypy, and two event-related potential (ERP) paradigms. The first paradigm was an auditory P300 "oddball" task designed to assess attentional functioning. The second was an N400 sentence paradigm particularly sensitive to language processing. RESULTS: Both relatives and individuals higher in schizotypy, but not their respective comparison groups, showed reductions in P300 amplitude. In the N400 paradigm, individuals higher in schizotypy, but not relatives, showed a reduced N400 effect. There were no differences in latency for either group on either component. CONCLUSIONS: The results suggest that both family status and schizotypal presentation independently contribute to disturbances in electrophysiologic measures sensitive to attention and language. Whereas higher levels of schizotypy appear to be associated with disturbances in both attention and language processing, family membership appears to place individuals at risk for attentional deficits alone.  相似文献   
34.
35.
目的了解安徽省志贺氏菌的流行菌型,并建立脉冲场凝胶电泳(PFGE)分子分型方法,为菌痢防控提供理论基础。方法对22株志贺氏菌进行血清分型、药物敏感试验和PFGE试验。结果22株志贺氏菌血清分型:B群19株,占总数86.5%;C群1株,占总数的4.5%;D群2株,占总数的9.0%。成功建立了菌痢的PFGE分子分型方法,并将我省22株流行株分为若干带型。试验结果进一步作聚类分析。结论安徽省菌痢流行株以福氏为主;安徽省PFGE分子分型方法和初步带型数据库对提高细菌检测水平有一定意义。  相似文献   
36.
37.
A great deal of controversy surrounds the question of the effectiveness of treatment of breast carcinoma, particularly radical surgical procedures in early cases.

The results of simple mastectomy followed by radiotherapy are compared with those of radical surgery in two series of cases, in Edinburgh and at the Mayo Clinic, respectively; despite the many variables involved in such a comparison, the figures are of interest because of their similarity.

Endocrine therapy in metastasizing breast cancer has profoundly altered malignant growth in some cases. Hypophysectomy is gaining favor and appears to be superseding adrenalectomy.  相似文献   
38.
39.
甲状腺术后瘢痕组织是甲状腺局部分切除术后由于手术方式及缝线填充而形成的组织,甲状腺术后瘢痕组织形成及其发生发展过程同一般的组织损伤修复病理过程一样,为渐进老化阶段的结缔组织,其内小血管稀少,胶原纤维增多[1]。由于甲状腺术后瘢痕组织其质地较硬,活动性差,超声声像图上表现缺乏典型特征,与癌灶极其相似,因此鉴别较困难。本文将介绍超声对于甲状腺术后的随诊应用,分析甲状腺术后瘢痕组织的超声检查特点并着重介绍超声动态观察甲状腺术后瘢痕组织的应用及其发展前景。  相似文献   
40.
目的 评价吡柔比星(THP)膀胱灌注预防腺性膀胱炎术后复发的疗效。方法 对30例腺性膀胱炎患者行经尿道汽化电切术,术后定期应用THP(40mg/50ml)膀胱内灌注化疗。结果 30例患者随访5~20个月,平均14.5个月,3例复发(10%)。未见有全身性药物不良反应,仅2例血白细胞降至3000个/ml。结论THP膀胱灌注预防腺性膀胱炎术后复发疗效满意,病人耐受性好,副作用小。  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