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   1211篇
  免费   70篇
  国内免费   16篇
耳鼻咽喉   2篇
儿科学   4篇
妇产科学   3篇
基础医学   108篇
口腔科学   7篇
临床医学   32篇
内科学   406篇
皮肤病学   1篇
神经病学   85篇
特种医学   29篇
外科学   11篇
综合类   162篇
一般理论   1篇
预防医学   250篇
眼科学   9篇
药学   73篇
中国医学   19篇
肿瘤学   95篇
  2024年   1篇
  2023年   5篇
  2022年   13篇
  2021年   23篇
  2020年   41篇
  2019年   20篇
  2018年   16篇
  2017年   15篇
  2016年   22篇
  2015年   25篇
  2014年   60篇
  2013年   79篇
  2012年   69篇
  2011年   100篇
  2010年   75篇
  2009年   91篇
  2008年   84篇
  2007年   76篇
  2006年   58篇
  2005年   43篇
  2004年   52篇
  2003年   31篇
  2002年   31篇
  2001年   23篇
  2000年   24篇
  1999年   22篇
  1998年   16篇
  1997年   17篇
  1996年   26篇
  1995年   17篇
  1994年   17篇
  1993年   9篇
  1992年   13篇
  1991年   9篇
  1990年   16篇
  1989年   5篇
  1988年   13篇
  1987年   4篇
  1986年   1篇
  1983年   3篇
  1982年   2篇
  1981年   5篇
  1980年   6篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   5篇
  1973年   2篇
  1972年   7篇
排序方式: 共有1297条查询结果,搜索用时 16 毫秒
1.
马旭  张涛 《现代预防医学》2022,(13):2465-2469
目的 分析2005—2020年宁夏阿拉善黄鼠鼠疫自然疫源地监测数据,了解该疫源地宿主动物及其寄生媒介生物种群特征,为准确制订预防控制措施提供科学依据。方法 运用描述性流行病学方法,用构成比、率和相对比等指标,对宁夏阿拉善黄鼠鼠疫自然疫源地2005—2020年间的监测数据进行统计分析;率的比较用卡方检验,检验水准α=0.05。结果 2005—2020年,宁夏阿拉善黄鼠鼠疫自然疫源地各监测点共鉴定啮齿动物18种10403只。其中,阿拉善黄鼠6511只,占鉴定总数的62.59%,为该地区绝对优势种群,平均鼠密度为0.51只/公顷;小型啮齿动物平均捕获率为1.39%,不同年度间捕获率比较差异具有统计学意义(x2=1198.982,P<0.05);鉴定蚤类14种45497只,其中方形黄鼠蚤蒙古亚种37181只,占鉴定总数的81.72%,为该地区绝对优势种群;鼠体平均染蚤率为60.41%,不同年份间鼠体染蚤率比较差异具有统计学意义(x2=1251.907,P<0.05),平均蚤指数为1.34;鼠疫病原学、血清学检测结果均为阴性。结论 宁夏阿拉善黄鼠鼠疫自然疫源地疫源性持续存在,发生动物间鼠疫流行的风险较低,但不能排除动物间鼠疫局部散发的可能性,需继续加强动物间鼠疫监测力度,适时开展监测预警及灭鼠工作,严防鼠疫疫情的发生。  相似文献   
2.
3.
4.
《Vaccine》2021,39(27):3641-3643
In the spring of 1656, an epidemic of bubonic plague suddenly fell on Naples, the capital of the Kingdom of the Two Sicilies. The epidemic had put a strain on the government authorities, forcing them to take sometimes drastic measures but, in most cases, scarcely decisive. The current health emergency caused by Covid-19 disease has many similarities with the epidemics of the past. Here we report the parallelism among plague and Covid-19 in several respects. Taking as a paradigm the plague epidemic of Naples of 1656, we can easily understand how history, showing us how past epidemics were managed and overcome, even with the intrinsic differences due to the limits of time and scientific progress, can still give us a useful lesson to face the present.  相似文献   
5.
内蒙古面临着多种类型疫源地鼠疫流行和复燃的风险。蒙古旱獭疫源地虽然暂未在国内发现动物间鼠疫流行,但过去检出过阳性血清,同时蒙古旱獭种群数量持续增加且分布范围不断扩大,毗邻的蒙古国和俄罗斯联邦的蒙古旱獭疫源地动物间鼠疫持续流行;达乌尔黄鼠疫源地动物间鼠疫时隐时现;长爪沙鼠疫源地动物间鼠疫流行猛烈,并频频波及人间。由于蒙古旱獭和达乌尔黄鼠鼠疫耶尔森菌菌株毒力明显高于长爪沙鼠鼠疫耶尔森菌菌株,且在历史上曾给当地带来深重灾难,因此内蒙古自治区鼠疫防控重点应在常规鼠疫监测的基础上,进一步加强蒙古旱獭和达乌尔黄鼠疫源地流行动态的监测,警惕该两个疫源地复燃并波及人间。  相似文献   
6.
目的 通过对以往青海地区链霉素治疗鼠疫病例单独和联合使用抗生素疗效的比较和分析,探索合理使用新型抗生素治疗鼠疫病例的新方法.方法 回顾性调查分析以往鼠疫病例,以年龄、病型、链霉素总用量、链霉素治疗时间为指标,对链霉素单独和联合应用治疗鼠疫病例的疗效进行比较和分析.采用SPSS 10.0软件进行有关统计学分析.结果 链霉素单独和联合应用治疗腺鼠疫,在链霉素总用量和治疗时间上有差别,经统计学检验差异有统计学意义;治疗肺鼠疫差异无统计学意义.结论 链霉素与环丙沙星联合应用治疗腺鼠疫时,可以降低链霉素的用量和缩短治疗时间;但治疗肺鼠疫时,链霉素的用量和缩短治疗时间无明显差异.  相似文献   
7.
PIRC rats (F344/NTac‐Apc am1137) mutated in the Apc gene spontaneously develop colon tumors thus mimicking familial adenomatous polyposis (FAP) and sporadic colorectal cancer (CRC) more closely than Apc‐based rodent models developing tumors mostly in the small intestine. To understand whether microscopic dysplastic lesions precede the development of macroscopic tumors, PIRC rat colon was examined for the presence of mucin depleted foci (MDF), microadenomas of the rodent and human colon. Few MDF (about 4/animal) were already present in 1‐month‐old rats and their number rapidly increases to about 250 in 8‐month‐old rats. These lesions showed Wnt signaling activation (nuclear β‐catenin accumulation) and were dramatically decreased by sulindac (320 ppm), a drug with chemopreventive activity (MDF/rat at 4 months: 156 ± 8 and 38 ± 6 in controls and sulindac‐treated rats, respectively, means ± SE, p < 0.001). Since altered proliferation and apoptosis could underlie the early phases of carcinogenesis, we studied these processes in the apparently normal colon mucosa (NM) of 1‐month‐old PIRC and wt rats. Colon proliferation (PCNA expression) was significantly higher in PIRC rats. Notably, PIRC rat NM showed resistance to apoptosis since it sustained proliferation and had lower apoptosis after a cytotoxic insult with 1,2 dimethylhydrazine. Gene expression of Myc, p21, Birc5, Ogg1, Apex1 and Sod2 were significantly up‐regulated in the NM of PIRC rat. The overall results put forward PIRC rat as useful model of colon carcinogenesis, either to study the process itself or to test in vivo chemopreventive agents in both short‐ and long‐term studies.  相似文献   
8.
9.
Purpose: Ionizing radiation-induced foci (IRIF) known also as DNA repair foci represent the most sensitive and specific assay for assessing DNA double-strand break (DSB). IRIF are usually visualized and enumerated with the aid of fluorescence microscopy using antibodies to phosphorylated γH2AX and 53BP1. Although several approaches and software packages were developed for quantification of IRIF, not one of them was commonly accepted and inter-laboratory variability in the outputs was reported. In this study, JCountPro software was validated for IRIF enumeration in two independent laboratories.

Materials and methods: Human lymphocytes were γ-irradiated at doses of 0, 2, 5, 10 and 50 cGy. The cells were fixed, permeabilized and IRIF were immunostained using appropriate antibodies. Cell images were acquired with automatic Metafer system. Endogenous and radiation-induced γH2AX and 53BP1 foci were enumerated using JCountPro. This analysis was performed from the same cell galleries by the researchers from two laboratories. Yield of foci was analyzed by either arithmetic mean (AM) value (foci/cell) or principal average (PA) derived from the approximation of foci distribution with Poisson statistics. Statistical analysis was performed using factorial ANOVA.

Results: Enumeration of 53BP1, γH2AX and co-localized 53BP1/γH2AX foci by JCountPro was essentially the same between laboratories. IRIF were detected at all doses and linear dose response was obtained in the studied dose range. PA values from Poisson distribution fitted the data better as compared to AM values and were more powerful and sensitive for IRIF analysis than the AM values. All JCountPro data were confirmed by visual focus enumeration.

Conclusions: We concluded that the JCountPro software was efficient in objectively enumerating IRIF regardless of an individual researcher’s bias and has a potential for usage in clinics and molecular epidemiology.  相似文献   

10.
《Indian heart journal》2016,68(2):192-193
Coronary artery fistula is an abnormal connection between a coronary artery and a cardiac chamber, a great artery or the vena cava. Although coronary artery fistulas are known to be congenital malformations they might occur due to infection, trauma or may be iatrogenic. We present a case with acquired coronary microfistula, without any history of interventional procedure.  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