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   6334篇
  免费   648篇
  国内免费   23篇
耳鼻咽喉   82篇
儿科学   270篇
妇产科学   189篇
基础医学   1140篇
口腔科学   147篇
临床医学   663篇
内科学   1084篇
皮肤病学   107篇
神经病学   375篇
特种医学   363篇
外科学   891篇
综合类   209篇
一般理论   6篇
预防医学   573篇
眼科学   96篇
药学   342篇
  1篇
中国医学   74篇
肿瘤学   393篇
  2021年   83篇
  2020年   65篇
  2019年   56篇
  2018年   72篇
  2017年   74篇
  2016年   82篇
  2015年   116篇
  2014年   119篇
  2013年   207篇
  2012年   267篇
  2011年   280篇
  2010年   198篇
  2009年   139篇
  2008年   227篇
  2007年   234篇
  2006年   218篇
  2005年   221篇
  2004年   198篇
  2003年   187篇
  2002年   175篇
  2001年   157篇
  2000年   191篇
  1999年   180篇
  1998年   106篇
  1997年   103篇
  1996年   108篇
  1995年   104篇
  1994年   108篇
  1993年   69篇
  1992年   137篇
  1991年   128篇
  1990年   146篇
  1989年   144篇
  1988年   130篇
  1987年   128篇
  1986年   122篇
  1985年   97篇
  1984年   95篇
  1983年   75篇
  1982年   57篇
  1981年   85篇
  1980年   58篇
  1979年   63篇
  1977年   56篇
  1973年   51篇
  1972年   51篇
  1958年   61篇
  1957年   89篇
  1955年   76篇
  1954年   68篇
排序方式: 共有7005条查询结果,搜索用时 15 毫秒
1.
2.
3.
宫腹腔镜联合手术诊治不孕症150例分析   总被引:14,自引:0,他引:14  
目的:探讨宫腹腔镜联合手术在诊治不孕症中的应用。方法:对150例不孕症患者行宫腹腔镜联合手术,对不孕症病因进行诊断,同时行治疗。结果:盆腔粘连和输卵管阻塞是不孕症的主要原因。子宫内膜息肉和正常盆腔占次要比例。子宫内膜异位症和多囊卵巢也是主要病因。150例同时行宫腹腔镜输卵管通液和各种疾病的治疗。联合手术后妊娠率为48.8%。结论:腹腔镜联合手术,在一次麻醉下,可以对不孕的原因全面评价和明确诊断,在诊断同时进行治疗,对不孕症的诊断和治疗有重大的意义,值得推广。  相似文献   
4.
Summary Five different isolates of influenza C virus which were isolated over a period of 32 years and from four different continents were compared by RNA genome oligonucleotide fingerprinting analyses. The earliest isolate of influenza C virus was reported in 1949 byTaylor (19) and served as a reference strain for this study.The results obtained using this technique of comparing relatedness between viruses clearly showed that all strains are distinct. However, the similarities in the pattern of the oligonucleotide fingerprints are marked for the more recent virus isolates (1966–1979), whereas the reference strain C/Taylor shows more pronounced differences.The results are consistant with the high degree of serological crossreaction amongst influenza C viruses isolated over a long period of time, a property which sets this group of viruses apart from type A and B members of the orthomyxoviridae.With 3 Figures  相似文献   
5.
6.
7.
The skeletal effects from intensive exercise throughout puberty are undefined. Forty-five female gymnasts and 52 controls were studied over 3 years, including a heredity aspect. The effects of size, maturity, exercise, and diet were identified using a multilevel regression model. Results demonstrated sustained skeletal benefits resulting from exercise throughout all stages of pubertal development. INTRODUCTION: Weight-bearing exercise is beneficial for peak bone mass development. However, whether skeletal benefits achieved with exercise are maintained if training remains intensive throughout the pubertal years is not entirely clear. The influence of familial resemblance for bone mass remains undefined in physically active versus inactive children. The aim of this study was to investigate the long-term influences of impact-loading exercise on bone quantity and quality in young females after controlling for growth, maturation, and hereditary factors. MATERIALS AND METHODS: At baseline, 45 gymnasts (G) and 52 normally active controls (C) 8-17 years of age were recruited. Anthropometry, diet, physical activity, and quantitative ultrasound (QUS) were measured annually for 3 consecutive years. DXA scans of total body (TB) and lumbar spine (LS) bone mineral content (BMC) and density (BMD) were taken three times at 1-year intervals. A multilevel regression model was fitted, and the independent effects of body size, maturity, physical activity, and diet were identified over time. To assess heredity influences, 27 G mothers and 26 C mothers volunteered for cross-sectional measurements of anthropometry, QUS, and BMC/BMD. RESULTS AND CONCLUSIONS: Gymnasts were smaller and lighter (as were their mothers) than controls, but they had significantly higher QUS and axial and appendicular BMC and BMD, with > 170 g more bone mineral in TB across puberty (after adjustment for maturity [years from peak height velocity], height, weight, energy, and protein intake). Gymnasts had up to 24-51% higher BMC and 13-28% higher BMD, depending on skeletal site. These results provide evidence of sustained skeletal benefits from impact-loading exercise, which are unlikely to result entirely from heredity, throughout pubertal years.  相似文献   
8.
Personal microenvironmental cooling has been used to enhance safety and extend the work capacity of laborers wearing protective clothing. Previous studies of air and liquid cooling have used either very low work rates or high environmental temperatures. Emergency work tasks frequently require high work rates and occur in moderate ambient temperatures. The purpose of this research was to examine the efficacy of intermittent personal cooling during rest and to compare liquid and air cooling systems in subjects engaged in hard work. Fourteen volunteers wearing chemical protective clothing performed treadmill walking at a metabolic rate of 430 W for 45 min followed by a 15-min rest at a wet-bulb globe temperature of 25 degrees C. During rest, volunteers received either no cooling, air cooling, or liquid cooling. Both cooling systems partially alleviated heat strain and increased work time with the air system offering slightly more effective cooling.  相似文献   
9.

Background  

The underlying causes of spinal manipulation hypoalgesia are largely unknown. The beneficial clinical effects were originally theorized to be due to biomechanical changes, but recent research has suggested spinal manipulation may have a direct neurophysiological effect on pain perception through dorsal horn inhibition. This study added to this literature by investigating whether spinal manipulation hypoalgesia was: a) local to anatomical areas innervated by the lumbar spine; b) correlated with psychological variables; c) greater than hypoalgesia from physical activity; and d) different for A-delta and C-fiber mediated pain perception.  相似文献   
10.
A case of life-threatening respiratory distress during a Caesarean section under spinal anaesthesia is reported. Possible causes of the event including anaphylactoid reactions and the methods of their diagnosis are discussed. The most likely cause of the episode was felt to be an anaphylactoid reaction to Syntocinon.  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