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   269264篇
  免费   24978篇
  国内免费   7481篇
耳鼻咽喉   2209篇
儿科学   9862篇
妇产科学   5467篇
基础医学   45267篇
口腔科学   4817篇
临床医学   23593篇
内科学   43614篇
皮肤病学   5276篇
神经病学   23367篇
特种医学   8014篇
外国民族医学   36篇
外科学   23159篇
综合类   32785篇
现状与发展   40篇
预防医学   13903篇
眼科学   3689篇
药学   25798篇
  105篇
中国医学   16170篇
肿瘤学   14552篇
  2024年   745篇
  2023年   4642篇
  2022年   9810篇
  2021年   12363篇
  2020年   10899篇
  2019年   10198篇
  2018年   10160篇
  2017年   10109篇
  2016年   9925篇
  2015年   10368篇
  2014年   17395篇
  2013年   18221篇
  2012年   14952篇
  2011年   17564篇
  2010年   13864篇
  2009年   13562篇
  2008年   13370篇
  2007年   12567篇
  2006年   11085篇
  2005年   9645篇
  2004年   8302篇
  2003年   7365篇
  2002年   5416篇
  2001年   4830篇
  2000年   4074篇
  1999年   3785篇
  1998年   3493篇
  1997年   3276篇
  1996年   3023篇
  1995年   2880篇
  1994年   2601篇
  1993年   2360篇
  1992年   1889篇
  1991年   1567篇
  1990年   1432篇
  1989年   1199篇
  1988年   1110篇
  1987年   1028篇
  1986年   1065篇
  1985年   1516篇
  1984年   1460篇
  1983年   1023篇
  1982年   1157篇
  1981年   963篇
  1980年   824篇
  1979年   707篇
  1978年   449篇
  1977年   371篇
  1976年   373篇
  1975年   220篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
目的比较山莨菪碱联合无创正压面罩通气(654-2+NIPPV)和传统机械通气(CMV)治疗急性呼吸窘迫综合征(ARDS)的临床效果,评估山莨菪碱联合无创正压通气在ARDS治疗中的作用。方法将各种原因所致ARDS患者42例随机分为654-2+NIPPV组(21例)和CMV组(21例),在给予病因治疗同时分别实施654-2+NIPPV和CMV。观察分析两组患者在治疗过程中动脉血气变化、并发症的发生率及治疗效果。结果654-2+NIPPV组有8例(38.1%)治疗失败转为气管插管实行CMV,其中6例(28.6%)死亡。CMV组死亡7例(33.3%),两组病死率无显著差异(P〉0.05)。两组治疗有效的患者在分别接受654-2+NIPPV和CMV治疗后1h和6h动脉血气有相似的显著改善。654-2+NIPPV组患者机械通气时间和住院时间短于CMV组(P〈0.05)。654-2+NIPPV组的并发症发生率低于CMV组(P〈0.05)。结论在经过选择的ARDS患者中,应用654-2+NIPPV治疗的临床效果与CMV相似。实施654-2+NIPPV可缩短机械通气和住院时间,减少并发症。654-2+NIPPV可作为经过选择的ARDS患者首选的通气支持治疗手段。  相似文献   
992.
This article highlights positive outcomes for a convenience sample of six women (49-64 years of age) with fibromyalgia syndrome (FMS) who participated in an exercise program over 5 years. This group showed improvement with various FMS symptoms,fitness, and psychosocial factors early in the program, then showed further improvement as a result of adding new exercises to the protocol during the fourth and fifth years. Data suggest that certain people with FMS can improve their functional capacity with exercise over time, and move to even higher levels of physical function while aging and coping with FMS. Practical advice is provided for rehabilitation nurses regarding exercise and FMS.  相似文献   
993.
The neurosteroid allopregnanolone (ALLO) or 3α-OH-5α-pregnane-20-one interacts with the GABA type A receptor chloride ion channel complex and enhances the effect of GABA. Animal and human studies suggest that ALLO plays an important role in several disorders including premenstrual syndrome, anxiety, and memory impairment. In contrast to ALLO, steroids with a hydroxy group in the 3β position usually exert a reducing effect and have recently attracted interest due to their suggested role in counteracting the negative action of ALLO. In this study, five different 3β-steroids were tested for their ability to modulate GABA-mediated chloride ion uptake in the absence and presence of ALLO in rat brain microsacs preparations. In addition, the effects of the 3β-steroids and their interaction with ALLO were investigated by patch-clamp recordings of spontaneous inhibitory postsynaptic currents (sIPSCs) in rat hypothalamic neurons from the medial preoptic nucleus (MPN). All tested 3β-steroids reduced the ALLO-enhanced GABA response in cerebral cortex, in hippocampus and in MPN. In cerebellum, only one had this effect. However, in the absence of ALLO, two of the 3β-steroids potentiated GABA-evoked chloride ion uptake and prolonged the sIPSCs decay time, whereas the others had little or no effect. Therefore, it is possible that at least some 3β-steroids can act as positive GABAA receptor modulators as well as negative modulators depending on whether or not ALLO is present. Finally, these results suggest that the 3β-steroids could be of interest as pharmacological agents that could counteract the negative effects of ALLO.  相似文献   
994.
995.
The pulmonary effects of closure of a patent ductus arteriosus (PDA) were investigated in 11 premature infants with severe respiratory distress syndrome. Successful closure of a PDA did not improve the short-term severity of pulmonary disease (24 and 48 h after treatment) as judged by the arterial/alveolar oxygen tension ratio or the amount of ventilatory support. Also, pulmonary mechanics measured 24 h before, 24 and 48 h after treatment, were not statistically different.Conclusion Infants with severe respiratory disease requiring high ventilation pressure and high oxygen concentration, where structural changes in the lungs are already established, will rarely show short-term improvement in pulmonary disease as a result of closure of a PDA. The overall clinical condition may, however, improve as a result of reduced cardiovascular strain. Earlier treatment of a PDA could reduce the ventilation period and the possible risk of developing chronic lung disease.  相似文献   
996.
目的:回顾分析75例严重急性呼吸综合症(SARS)病例,探讨该病影像学表现及其与临床治疗有关的问题。方法:全部75例患者均行胸片检查,一般隔日行影像追踪复查。结果:胸部X线表现为肺实质渗出病灶为主,肺内网状改变及肺门片块影较少。影像表现与临床病程有一定关系。结论:胸部影像表现以肺实质渗出病灶较常见。胸片检查是进行本病诊断和评估病程及疗效的重要方法。  相似文献   
997.
The accurate assessment of body composition is of importance in the Prader-Willi syndrome. Many techniques are not applicable due to ethical or practical reasons. However, the bioelectrical impedance technique is a rapid, painless, noninvasive method of estimating total body water and hence, fat-free mass in obese children and adolescents. We have compared estimates of total body water derived from bioelectrical impedance with actual measurements taken, using H218O dilution, in 14 children with Prader-Willi syndrome. Existing equations for predicting total body water from impedance showed a bias to underestimate actual measures of body water. There were positive correlations between the degree of underestimation with age and body fatness. It is possible that changes in body shapes influence bioelectrical impedance measurements in obese individuals, and that a prediction equation based upon a normal population will not be applicable to obese individuals. © 1992 Wiley-Liss, Inc.  相似文献   
998.
磁场对电解铝作业工人免疫功能影响的研究   总被引:2,自引:0,他引:2       下载免费PDF全文
章孟本  朱继周  宋世震 《中国工业医学杂志》1992,5(4):197-198,255-256
对某铝厂电解车间采用CT_3-A型交直流特斯拉计测定了电解槽近场区不同高度、不同距离及人体表面不同部位的磁场强度。结果表明作业场所及人体体表的磁场强度为自然界磁场强度的数倍至数十倍。对接触磁场、工龄在20年以上的工人,进行了免疫功能的测定。结果表明该场所的磁场强度对工人免疫功能有抑制作用。由于该作业场所除磁场外,还有其他化学、物理因素的危害,因此,这种免疫功能的改变,可能是磁场等综合因素所造成的。  相似文献   
999.
The objective of this blinded, randomized, prospective study was to assess whether supplementation of normal diet with omega-3 polyunsaturated fatty acids can reduce angiographically defined restenosis following coronary angioplasty. The study included all patients undergoing coronary angioplasty in this institution between January 1988 and January 1989. One hundred and twenty patients enrolled, 60 in each treatment group. All were randomized to either supplementation of normal diet with 3 g of omega-3 polyunsaturated fatty acids per day started 1-2 days prior to angioplasty and continued for 6 months (treatment group), or to receive standard therapy only (control group). Quantitative angiographically defined restenosis was assessed at 6 months post angioplasty. Restenosis occurred in 27.8% (95% CI 18.0-37.7%) of lesions in the treatment group and in 28.3% (CI 16.9-39.7%) of lesions in the control group, but the difference was not statistically significant. The study showed that diet supplemented with 3 g of omega-3 polyunsaturated fatty acids started 1-2 days preceding angioplasty does not reduce angiographically defined restenosis rate.  相似文献   
1000.
This article describes plastic surgery patients who sought symmetrical recontouring of the width of the face and skull. The basic demographic and personality characteristics of these facial width deformity (FWD) patients and the surgical procedures performed on them are discussed. Details of the surgical and psychological management of three representative cases are given. Speculative conclusions regarding the general characteristics of the FWD population are offered. Suggestions are proposed for a combined surgical-medical psychotherapeutic collaboration in managing these patients.  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