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   22409篇
  免费   2119篇
  国内免费   679篇
耳鼻咽喉   108篇
儿科学   601篇
妇产科学   334篇
基础医学   3093篇
口腔科学   429篇
临床医学   3320篇
内科学   2757篇
皮肤病学   231篇
神经病学   1862篇
特种医学   364篇
外国民族医学   8篇
外科学   1091篇
综合类   2504篇
现状与发展   5篇
一般理论   4篇
预防医学   3262篇
眼科学   338篇
药学   2478篇
  19篇
中国医学   582篇
肿瘤学   1817篇
  2024年   59篇
  2023年   348篇
  2022年   540篇
  2021年   810篇
  2020年   895篇
  2019年   853篇
  2018年   784篇
  2017年   803篇
  2016年   770篇
  2015年   897篇
  2014年   1360篇
  2013年   1932篇
  2012年   1242篇
  2011年   1315篇
  2010年   1013篇
  2009年   1077篇
  2008年   1143篇
  2007年   1155篇
  2006年   996篇
  2005年   936篇
  2004年   799篇
  2003年   738篇
  2002年   664篇
  2001年   558篇
  2000年   440篇
  1999年   401篇
  1998年   376篇
  1997年   309篇
  1996年   269篇
  1995年   244篇
  1994年   198篇
  1993年   202篇
  1992年   156篇
  1991年   145篇
  1990年   110篇
  1989年   89篇
  1988年   90篇
  1987年   72篇
  1986年   60篇
  1985年   59篇
  1984年   59篇
  1983年   45篇
  1982年   43篇
  1981年   34篇
  1980年   32篇
  1979年   27篇
  1978年   16篇
  1977年   10篇
  1976年   10篇
  1975年   9篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
81.
核酸原位杂交程序中探针和靶基因的加热变性和杂交为整个程序中最重要的环节,目前国内外最常用的方法是在切片上滴加DNA探针溶液后用盖玻片复盖组织,并加胶泥或其他封固剂封闭玻片四周,变性杂交后需拆除盖玻片,这一操作过程易损坏组织切片或出现干片、脱片。作者针对上述情况,对传统的核酸原位杂交方法中的部分程序加以改良,采用不加盖玻片直接在蒸汽中变性方法,经多次实验证明此方法稳定、可靠、简便,结果满意。  相似文献   
82.
Every child despite his individual differences and uniqueness is to be considered of equal worth. He should therefore be entitled to equal social, economic, civil and political rights, so that he may fully realise his inherent potential and share equally in life (Gill, 1979).

Obviously, these values are rooted in the humanistic philosophy of any nation's declaration of independence. In accordance with these value premises therefore “any act of commission or ommission by individuals, institutions or the society as a whole, and any conditions which deprive children of equal rights and liberties and interfere with their optimal development, constitutes by definition abuse or neglectful acts or conditions” (Gill, 1979).

Child abuse is a significant contemporary community problem. Although children have been maltreated throughout history, our community has been silent in defence of abused children. Child abuse is not a phenomenon of the 20th Century nor is it unique to our society and culture alone. It has occurred throughout the recorded history of man. The future of any nation depends on its children and their capabilities. For this reason, they must be given a full chance.  相似文献   
83.
胃癌组织COX-2的表达及其与细胞增殖和凋亡的关系   总被引:8,自引:1,他引:7  
目的 :探讨环氧化酶 - 2 (cyclooxygenase - 2 ,COX - 2 )在胃癌组织中的表达与癌细胞增殖和凋亡的关系。 方法 :采用免疫组织化学的方法检测 4 3例胃癌患者COX - 2和增殖细胞核抗原 (PCNA)的表达 ,用TUNEL法检测原位细胞凋亡的情况。分别计算细胞增殖指数 (MI)和凋亡指数 (AI)。结果 :胃癌组织COX - 2表达的阳性率为 6 0 .4 7% ,明显高于对照组 (P <0 .0 1)。COX - 2的高表达与胃癌淋巴结的转移和临床分期有关 ,与肿瘤大小、浸润深度、分化程度均无关。COX - 2阳性胃癌组中MI高于COX - 2阴性胃癌组 ,而AI却低于COX - 2阴性胃癌组 (P均 <0 .0 1)。结论 :COX - 2的过度表达可促进胃癌细胞增殖、抑制细胞凋亡 ,在胃癌的发生、发展过程中起着重要的作用。  相似文献   
84.
This paper reports a test of the efficacy of Familias Unidas, a Hispanic-specific, ecologically focused, parent-centered preventive intervention, in promoting protection against and reducing risk for adolescent behavior problems. Specifically, the intervention was designed to foster parental investment, reduce adolescent behavior problems, and promote adolescent school bonding/academic achievement, all protective factors against drug abuse and delinquency. One-hundred sixty seven Hispanic families of 6th and 7th grade students from three South Florida public schools were stratified by grade within school and randomly assigned to intervention and no-intervention control conditions. Results indicated that Familias Unidas was efficacious in increasing parental investment and decreasing adolescent behavior problems, but that it did not significantly impact adolescent school bonding/academic achievement. Summer-vacation rates of adolescent behavior problems were six times higher in the control condition than in the intervention condition. Furthermore, change in parental investment during the intervention was predictive of subsequent levels of adolescent behavior problems. The findings suggest that Familias Unidas is efficacious in promoting protection and reducing risk for adolescent problem behaviors in poor immigrant Hispanic families.  相似文献   
85.
Background :
In an attempt to determine the biological significance of nuclear morphometric findings, measurements of mean nuclear volume (MNV) and nuclear roundness factor (NRF) were compared to the immunoreactivityof p53 expression and proliferating cell nuclear antigen (PCNA) in human bladder cancer.
Methods :
MNV and NRF were measured using stereological methods. Expression of p53 and PCNA were determined by immunohistochemical staining. Specimens from 111 patients with previously untreated bladder cancer were analyzed.
Results :
The mean MNV was 235.8 ± 1 33.6 μm3 for the 81 patients with p53-labeling index (LI) less than 10% and 337.2 ± 141.0 μn3 for the 30 patients with p53 LI greater than 10% (P = 0.008). There was Resign if icant correlation between NRF and expression of p53. The mean MNV was 220.1 ± 1 20.5 μm3 for the 67 patients with PCNA LI less than 28% (the mean value of PCNA LI) and 328.9 ± 149.2 μm3 in 44 patients with PCNA LI greater than 28% (P= 0.0001). The mean NRF was 80.7 ± 4.2 for the 67 patients with PCNA LI less than 28%, and 82.3 ± 3.4 for the 44 patients with PCNA LI more than 28% (P= 0.04). Conclusion: Nuclear morphometric findings may reflect the proliferative potential of cancer eel Is of the bladder, as indicated by findings of immunostaining for p53 and PCNA.  相似文献   
86.
87.
目的 探讨慢性阻塞性肺疾病(慢阻肺)患者的家庭支持与自我概念的关系。方法 用方便抽样法选取108位慢阻肺患者,应用修订的个人资源问卷、自我概念量表和一般资料问卷分别测定其家庭支持、自我概念水平和一般资料。结果 该组患者家庭支持程度为中到高度,自我概念中度积极;家庭支持与总的自我概念呈中度正相关,与自我概念中的体感、自我一致性、理想自我及道德一伦理一精神自我有显著相关.与体象无关。结论 慢阻肺患者的家庭支持水平越高,其自我概念越积极。  相似文献   
88.
Forty-two cases of haemangiopericytoma were studied retrospectively using immunohistochemical staining with PC10, a monoclonal antibody to PCNA. The percentage of tumour cells with positive staining for PCNA was found to correlate well with histological grading. Clinical follow-up data were available in 25 adults and showed no known deaths in 11 cases with a low proportion (less than 14%) of positive cells. Out of 14 cases with a high number (greater than or equal to 14%) of positive cells, seven patients are known to have died, two had metastases, and in a further two there have been multiple recurrences of tumour. DNA flow cytometry was performed on 26 cases but this showed no correlation with PC10 staining or clinical outcome. Staining with PC10 may be of particular value in the identification of patients at greatest risk of rapid tumour metastasis and early death.  相似文献   
89.
Summary When a baby is born with a visible disfigurement, then parents need to adjust to the loss of the anticipated 'perfect' child and thus accept their baby. The impact of the birth on the parents is described in the context of a measure which identifies areas of potential difficulty. The two groups studied were parents of children with cleft palates and parents of children with congenital hand deficit. A wide range of adjustment was found. There was no significant difference between the two groups in terms of their overall adjustment, but there were individual differences in adjustment which did not relate to the severity or type of anomaly. The only significant variable found to relate to parental adjustment was perceived family support.  相似文献   
90.
本文对14例HBV-DNA阳性患儿的家庭成员23人进行血清学检测,并收集22例正常人血清为对照组。23例家庭成员中HBV-DNA阳性率为34.8%(8/23),明显高于对照组4.5%(1/22),P<0.01。HBV-DNA阳性率在患儿的双亲为40%(4/10),而在其祖父母辈为33.33%(3/9),二者无显著差异(P>0.05)。提示乙肝病毒感染的家庭聚集性存在双亲或祖父母辈与患儿间的易感性相似。  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