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   3480篇
  免费   209篇
  国内免费   88篇
耳鼻咽喉   35篇
儿科学   70篇
妇产科学   53篇
基础医学   371篇
口腔科学   42篇
临床医学   345篇
内科学   628篇
皮肤病学   95篇
神经病学   263篇
特种医学   42篇
外科学   409篇
综合类   341篇
预防医学   502篇
眼科学   24篇
药学   221篇
中国医学   235篇
肿瘤学   101篇
  2024年   5篇
  2023年   42篇
  2022年   72篇
  2021年   107篇
  2020年   89篇
  2019年   138篇
  2018年   153篇
  2017年   121篇
  2016年   95篇
  2015年   110篇
  2014年   216篇
  2013年   253篇
  2012年   165篇
  2011年   220篇
  2010年   181篇
  2009年   202篇
  2008年   183篇
  2007年   177篇
  2006年   145篇
  2005年   172篇
  2004年   114篇
  2003年   84篇
  2002年   74篇
  2001年   81篇
  2000年   49篇
  1999年   54篇
  1998年   36篇
  1997年   22篇
  1996年   25篇
  1995年   34篇
  1994年   18篇
  1993年   10篇
  1992年   10篇
  1991年   6篇
  1990年   4篇
  1989年   5篇
  1986年   3篇
  1985年   36篇
  1984年   50篇
  1983年   30篇
  1982年   38篇
  1981年   36篇
  1980年   21篇
  1979年   22篇
  1978年   19篇
  1977年   16篇
  1976年   9篇
  1975年   5篇
  1974年   10篇
  1973年   6篇
排序方式: 共有3777条查询结果,搜索用时 125 毫秒
21.
Chromosome 1p36 deletion syndrome is characterized by hypotonia, moderate to severe developmental and growth retardation, and characteristic craniofacial dysmorphism. Muscle hypotonia and delayed motor development are almost constant features of the syndrome. We report a 4-year-old Japanese girl with 1p36 deletion syndrome whose muscle pathology showed congenital fiber type disproportion (CFTD) myopathy. This is the first case report of 1p36 deletion associated with CFTD. This association may indicate that one of the CFTD loci is located at 1p36. Ski proto-oncogene −/− mice have phenotypes that resemble some of the features observed in patients with 1p36 deletion syndrome. Because fluorescent in situ hybridization analysis revealed that the human SKI gene is deleted in our patient, some genes in 1p36, including SKI proto-oncogene, may be involved in muscle hypotonia and delayed motor development in this syndrome. Received: March 4, 2002 / Accepted: July 7, 2002  相似文献   
22.
In order to delineate parameters that might discriminate between allergic subjects who develop R or R-P symptoms during natural antigen exposure, 26 subjects allergic to grass or ragweed pollen were classified into R or R-P groups, and then the antigen sensitivity and degree of in vivo mediator release were compared. Antigen-skin sensitivity was quantitated by dilutional skin-test titration, and bronchial sensitivity was quantitated by the amount of inhaled antigen required to receive the FEV1 by 20%. Mediator release was determined by measuring the amount of histamine that was released into skin chambers during antigen incubation and the rise in plasma histamine and serum NCA during antigen-induced bronchospasm. Compared to the 13 R subjects, the 13 R-P subjects were: (1) more sensitive to antigen by both skin-test and inhalation challenge, (2) responded to inhalation of antigen with a greater fall in FEV1 and a greater rise in serum NCA and plasma histamine, and (3) released more histamine into skin chambers after antigen incubation. Even when R and R-P subjects were matched by comparing only subjects with equal skin sensitivity to antigen, greater increases in serum NCA and plasma histamine occurred after inhalation of antigen in the R-P subjects. These data are consistent with the hypothesis that allergic rhinitis subjects who develop pulmonary symptoms during natural pollen exposure are more sensitive to antigen and release more mediators in response to antigen administration. It is therefore possible that the degree of mediator release may be an important factor in determining the pattern of clinical responses to antigen exposure.  相似文献   
23.
本文采用MTT微量酶反应比色法,研究了溴氰菊酯对白纹伊蚊C6/36细胞的杀伤作用、形态影响以及受损细胞的恢复。结果发现用溴氰菊酯处理24h后,对C6/36细胞的半数毒性浓度(IC50)为7488μg/ml,且毒性作用强度随着药物浓度增加而增强。溴氰菊酯浓度在20μg/ml以上时可以诱发C6/36细胞形态学改变,表现为细胞呈多形性、细胞间有间隙、胞质内充满颗粒,以后随药物浓度的升高,胞质出现空泡、染色质凝成粗大颗粒或无结构大块、大片细胞脱落、崩解、死亡。高浓度溴氰菊酯(160μg/ml)作用于C6/36细胞,其受损细胞的恢复与作用时间有关,作用24h的细胞,在经历一段生长停滞后,可缓慢恢复,而作用48h的细胞,则不可逆转的死亡  相似文献   
24.
高脂高胆固醇饮食小型猪CD36表达的变化   总被引:1,自引:0,他引:1       下载免费PDF全文
目的:用高脂高胆固醇饮食喂养贵州小香猪,探讨高脂高胆固醇饮食小香猪清道夫受体CD36表达的变化。方法:采用高脂高胆固醇饲料喂养贵州小香猪,每2个月末称体重并从禁食过夜的小香猪眶静脉窦采集血样,检测血脂浓度。血浆总胆固醇、甘油三酯、高密度脂蛋白胆固醇的浓度均用酶法测定;采用逆转录-聚合酶链反应、蛋白质印迹和免疫组织化学分别检测CD36 mRNA和蛋白质的表达。 结果:喂养2个月后,实验组血浆总胆固醇、高密度脂蛋白胆固醇含量明显高于正常对照组;血浆甘油三酯水平从第4个月末开始升高, 在第7个月末明显增加;肝组织、胸主动脉和肾脏组织CD36表达上调,同时观察到高脂高胆固醇小型猪胸主动脉PPARγ的表达上调。 结论:提示高脂高胆固醇饲料可引起贵州小型猪的脂质代谢紊乱,并导致肝组织、胸主动脉和肾脏组织的CD36表达上调以及胸主动脉PPARγ的表达上调。  相似文献   
25.
26.
BACKGROUND: Environmental control has been put forward as an integral part of the management of house dust mite (HDM) allergy in sensitized patients. To validate this statement allergic disorders involved in HDM allergy--allergic asthma, rhinitis and atopic eczema/dermatitis syndrome (AEDS)--should be taken together and studied in terms of the efficacy of environmental control. Because a generic quality of life questionnaire exceeds the border of disease, this may be used as major outcome parameter. RESEARCH OBJECTIVE: To study the effects of bedding encasings in HDM allergic patients with asthma, rhinitis and AEDS. MATERIAL AND METHODS: A total of 224 adult HDM allergic patients with rhinitis and/or asthma and/or dermatitis were randomly allocated impermeable or nonimpermeable encasings for mattress, pillow and duvet. Short form 36 (SF-36) was filled in at baseline and after 12 months. Results: Lower physical (P = 0.01) and emotional (P < 0.001) sumscores were seen in females. Also, the presence of asthma resulted in lower physical sumscore (P = 0.01). However, no effect was seen of encasings on either sumscore. CONCLUSION: Bedding encasings do not improve quality of life in a mixed population of subjects with combinations with rhinitis, asthma and atopic dermatitis and sensitized to HDMs.  相似文献   
27.
Summary The effects of the-carboline ZK 93426, a putative benzodiazepine receptor antagonist, were investigated in the social interaction test of anxiety and in the holeboard. Like the receptor antagonist Ro 15-1788, ZK 93426 (2.5–10 mg/kg) caused a specific reduction in social interaction (interpreted as an anxiogenic effect) and caused a significant elevation in exploratory head-dipping (5 mg/kg). When low (ineffective) doses of both compounds (1 mg/kg ZK 93426; 4 mg/kg Ro 15-1788) were administered together they significantly reduced social interaction. No further reductions in social interaction were observed when effective doses of both compounds (5 mg/kg ZK 93426; 10 mg/kg Ro 15-1788) were tested in combination; it is likely that this is due to almost total benzodiazepine receptor occupancy at effective doses of either compound. When doses of each compound (5 mg/kg ZK 93426; 10 mg/kg Ro 15-1788) that resulted in stimulation of head-dipping were examined in combination, the elevation in exploration was no longer observed. Since at higher doses of both compounds there is an attenuation of the elevation in head-dipping, it is again likely that the effects of the two compounds are additive.  相似文献   
28.
ObjectivesA number of studies have shown an association between smoking habit and quality of life, but these have mainly involved cross-sectional data. This study takes advantage of longitudinal panel data to estimate the effect of the transition from “smoker” to “ex-smoker” status (smoking cessation) on health-related quality of life (HRQoL), measured by SF-36, in an Australian general population sample.MethodsPanel data from 13 waves (2001-2013) of a nationally representative longitudinal survey of Household Income and Labour Dynamics of Australia (HILDA) were used; 1858 respondents (5% of total HILDA sample) who experienced only 1 cessation event in their HILDA life were selected. HRQoL trajectories elicited by SF-36 (0-100 scale, worst to best health) were modeled before and after cessation events using a piecewise (segmented) 2-way fixed-effect linear regression, adopted to capture within-person differences. This enabled measurement of changes of regression slopes and intercept while controlling time-invariant characteristics (eg, country of birth, gender) and time-varying changes in health status.ResultsAnnual pre-post intervention improvements were estimated for the following dimensions: role physical 0.65 (95% CI 0.62-1.24), bodily pain 0.48 (95% CI 0.10-0.86), general health 0.55 (95% CI 0.2-0.9), and the physical component summary score 0.22 (95% CI 0.01-0.04). Immediate effects (discontinuity at the time of cessation) of smoking cessation existed for bodily pain –1.5 (95% CI –2.52 to –0.40) and general health 1.82 (95% CI 1.01-2.62). The effects for mental health domains were not significant.ConclusionsAdjusting for all unmeasured time-invariant confounders and controlling the effect of time, this study revealed the varied effects of smoking cessation on HRQoL; it has positive effect on physical and general health but nonsignificant effect on mental aspects. Preference-based utility measures based on SF-6D capture changes that can be measured in several of the domains of the SF-36.  相似文献   
29.
目的:探讨SF-36量表用于农村居民健康状况测定的可能性。方法:用中文版SF-36量表测定富阳2-7名14岁以上的农村居民,分析其信度,效度。结果:除了SF,RE维度,其余6维度内部一致性信度系数大于0.50,7维度内部一致性信度大于与其他维度的相关,因子分析产生3个主成分,累计方差贡献为64.6%,65岁以上者无应答,青年组与中年组各维度平均分数差异不显著,不同性别只在RP维度上判别显著,吸烟者与不吸烟者,饮酒者与不饮酒者的得分差异不显著,不同文化程度人群的得分差异不显著。结论:尚需更多证据支持SF-36量表适用于农村居民健康状况测定。  相似文献   
30.
四川省城乡居民SF-36评价参考值   总被引:8,自引:0,他引:8  
目的 制定 36条目简明量表 ( SF- 36 )参考值用于国内生命质量评价。方法 采用美国的评分标准及中国评分标准分别对四川省 16 0 3名农村居民和 6 46名城市居民的生命质量进行评价 ,并与香港及美国常模比较。结果 中国评分标准与美国评分标准所得结果高度相关 ,8个领域的相关系数均在 0 .98以上 ,但两种评分标准所得结果的差异有显著性 ;四川省城乡居民 SF- 36评价结果与香港及美国常模比较 ,更接近香港评价值 ;不同年龄、性别及城乡人群之间的评分结果有显著性差异。结论 制定了四川省城乡不同性别及年龄居民的 SF- 36评价参考值 ,为在国内使用 SF- 36作为生命质量评价工具奠定了基础  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