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   860篇
  免费   25篇
  国内免费   11篇
耳鼻咽喉   1篇
儿科学   38篇
妇产科学   7篇
基础医学   63篇
口腔科学   10篇
临床医学   60篇
内科学   109篇
皮肤病学   29篇
神经病学   5篇
特种医学   98篇
外科学   105篇
综合类   260篇
预防医学   29篇
眼科学   4篇
药学   32篇
肿瘤学   46篇
  2024年   1篇
  2023年   3篇
  2022年   4篇
  2021年   8篇
  2020年   3篇
  2019年   5篇
  2018年   7篇
  2017年   7篇
  2016年   6篇
  2015年   28篇
  2014年   14篇
  2013年   18篇
  2012年   20篇
  2011年   14篇
  2010年   46篇
  2009年   45篇
  2008年   35篇
  2007年   44篇
  2006年   58篇
  2005年   41篇
  2004年   53篇
  2003年   23篇
  2002年   25篇
  2001年   17篇
  2000年   19篇
  1999年   27篇
  1998年   40篇
  1997年   49篇
  1996年   52篇
  1995年   32篇
  1994年   29篇
  1993年   9篇
  1992年   8篇
  1991年   5篇
  1990年   7篇
  1989年   7篇
  1988年   15篇
  1987年   9篇
  1986年   10篇
  1985年   8篇
  1984年   11篇
  1983年   4篇
  1982年   7篇
  1981年   7篇
  1980年   4篇
  1978年   3篇
  1977年   4篇
  1976年   2篇
  1975年   2篇
  1970年   1篇
排序方式: 共有896条查询结果,搜索用时 0 毫秒
61.
62.
A hospital-based case-control study was carried out to clarify the characteristics of mucoid presentation of acute enterocolitis in children. One hundred sixty-eight cases of acute mucoid enterocolitis (study population) were compared with 200 cases of watery diarrhoea and 118 cases of blood dysentery (control groups) on the basis of clinical characteristics and findings on stool examination. Study and control groups were comparable with respect to age, body weight and nutritional status. There was no significant difference in clinical characteristics (duration of diarrhoea, stool frequency, presence of vomiting, fever and dehydration) between patients suffering from mucoid enterocolitis and blood dysentery. However, watery diarrhoea patients had significantly high frequencies of vomiting (p = 0.00001) and dehydration (p  相似文献   
63.
64.
In a prospective survey of infants born in a single maternity unit, asymptomatic faecal colonisation by Clostridium difficile occurred in 31 (47%) of 66 babies who provided a faecal sample during week one of life and at age 14 and 28 days, and in 46 (30.7%) of the total of 150 babies for whom at least one faecal sample was obtained during the month of study. There was no evidence for acquisition of the organism from the mother during delivery and colonisation was unrelated to the means of delivery, infant sex, means of feeding, duration of hospital stay, or antibiotic treatment. New colonisation occurred throughout the month of the study and further evidence for environmental acquisition was obtained by the finding of a similar strain of C difficile in 7 babies from one ward together with positive environmental cultures. Colonisation was frequently transient and occasionally intermittent; most infants kept the same strain during their period of carriage. Twenty two (47.8%) babies colonised by C difficile had low titres of cytopathic faecal toxin but none had symptomatic diarrhoea or features of necrotizing enterocolitis. The in vitro toxigenic potential of 57 toxigenic isolates from 36 babies was low and 12 babies carried non-toxigenic strains. Transient colonisation by C difficile in early life is almost certainly more common than is generally recognized and the neonate provides an important reservoir of potential infection.  相似文献   
65.
A modified Western blot (WB) that includes both shared (r21e) and unique recombinant envelope proteins from human T-lymphotropic virus (HTLV) type I (rgp46I) and type II (rgp46II) was compared to conventional HTLV serologic tests in 379 United States blood donors and individuals residing in diverse geographic regions, and the specimens were categorized as positive (n = 158), indeterminate (n = 158), or negative (n = 63) for HTLV infection. Of the 158 HTLV-I/II-positive specimens (66 requiring radioimmunoprecipitation assay [RIPA] for confirmation), 156 reacted concordantly with r21e, gag, and either rgp46I or rgp46II, thus eliminating the need for RIPA in all but two specimens and yielding a test sensitivity of 98.7 percent. Of the 158 indeterminate and 63 negative specimens, none reacted with r21e and rgp46I or rgp46II, yielding a test specificity of 100 percent. Furthermore, analysis of an additional 184 consecutive specimens from a retrovirology reference laboratory demonstrated that the modified WB correctly identified 27 of 28 HTLV-I specimens and all 13 HTLV-II specimens, with a test sensitivity of 97.6 percent. None of specimens that were indeterminate or nonreactive in conventional WB and/or RIPA and none of the screening enzyme immunoassay-negative specimens reacted with r21e and either rgp46I or rgp46II, for a test specificity of 100 percent. Thus, the modified WB appears to be highly sensitive and specific for simultaneous detection and discrimination of HTLV-I from HTLV-II and has the advantage of being a one-step assay that is easily performed in all types of laboratory settings and allows rapid, reliable, and standardized testing for HTLV-I/II infection.  相似文献   
66.
目的 建立早产儿三元整合式教育方案,并探讨其培训效果。方法 组建三元整合教育团队,按照早产儿的发育发展特点构建教育课程,搭建教育平台,包括开办家长学校、开展家长微课堂、视频引导、家长床旁照护操作培训等。采用NICU家长满意度调查表调查并比较培训前后家长满意度。结果 培训后早产儿家长的满意度总分为(191.90±0.20)分,培训前满意度总分为(176.00±4.40)分,差异有统计学意义(t=-41.68,P<0.001);培训前后家长的知识和信息维度、家长参与照护维度、医护人员专业态度维度得分的比较,差异有统计学意义(t1=-20.83,P1<0.001;t2=-27.30,P2<0.001;t3=-27.10,P3<0.001)。结论 早产儿三元整合式教育方案能提升家长的照护知识和参与照护能力,提高家长对医护人员专业态度的满意度。  相似文献   
67.
目的:目前临床进行隧道法舌根射频治疗时,其作用参数的设置仍缺乏统一的标准,故通过计算机三维重建射频损伤区域,分析猪舌根射频损伤体积与射频能量、时间的关系,从中得出应用舌根隧道法射频治疗的最佳作用能级和作用时间。 方法:实验于2006-06/2007-05在上海交通大学耳鼻喉科研究所完成。将36只实验用猪以射频作用能级1,2,3,4,5,6随机分成6组,每组6头猪,各个猪舌的作用时间分别设置为2,5,10,15,20,25s。用Coblation射频发生仪及Reflex55刀头进行猪舌根射频操作。射频作用后的舌根组织行连续冰冻切片,苏木精-伊红染色后,进行序列组织切片的全貌二维图像采集,对拟重建的结构进行边界提取和图像分割。将提取分割图像导入Image-Pro Solution图像处理软件,利用3D Constructor插件进行三维重建,并根据设定参数进行体积计算。用SPSS10.0统计学软件对所测数据进行统计学分析。 结果:①作用能级固定时,舌根组织射频损伤体积随时间延长而增大,符合Logarithmic回归曲线。②作用时间固定时,舌根组织射频损伤体积随能级增大而增大,符合直线回归。③射频损伤体积随能量增大而增加亦符合Logarithmic回归曲线。④Coblation射频治疗系统在能级6时,在作用10s之前,损伤体积随作用时间增加而迅速增加,其后变化趋势平缓,超过20s后损伤体积无显著增加。 结论:①舌根区域射频治疗时,舌根组织射频损伤体积与时间或能量呈Logarithmic曲线相关,与能级呈直线相关。②Coblation射频治疗系统在能级6时,最佳作用时间范围为10-20s。  相似文献   
68.
Gellan gum (GG)‐based hydrogels are advantageous in tissue engineering not only due to their ability to retain large quantities of water and provide a similar environment to that of natural extracellular matrix (ECM), but also because they can gelify in situ in seconds. Their mechanical properties can be fine‐tuned to mimic natural tissues such as the nucleus pulposus (NP). This study produced different formulations of GG hydrogels by mixing varying amounts of methacrylated (GG‐MA) and high‐acyl gellan gums (HA‐GG) for applications as acellular and cellular NP substitutes. The hydrogels were physicochemically characterized by dynamic mechanical analysis. Degradation and swelling abilities were assessed by soaking in a phosphate buffered saline solution for up to 170 h. Results showed that as HA‐GG content increased, the modulus of the hydrogels decreased. Moreover, increases in HA‐GG content induced greater weight loss in the GG‐MA/HA‐GG formulation compared to GG‐MA hydrogel. Potential cytotoxicity of the hydrogel was assessed by culturing rabbit NP cells up to 7 days. An MTS assay was performed by seeding rabbit NP cells onto the surface of 3D hydrogel disc formulations. Viability of rabbit NP cells encapsulated within the different hydrogel formulations was also evaluated by Calcein‐AM and ATP assays. Results showed that tunable GG‐MA/HA‐GG hydrogels were non‐cytotoxic and supported viability of rabbit NP cells. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
69.
70.
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