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   12325篇
  免费   1604篇
  国内免费   265篇
耳鼻咽喉   45篇
儿科学   140篇
妇产科学   110篇
基础医学   1013篇
口腔科学   169篇
临床医学   1046篇
内科学   1067篇
皮肤病学   67篇
神经病学   627篇
特种医学   454篇
外科学   846篇
综合类   2161篇
现状与发展   1篇
一般理论   8篇
预防医学   3673篇
眼科学   103篇
药学   1440篇
  8篇
中国医学   727篇
肿瘤学   489篇
  2024年   83篇
  2023年   391篇
  2022年   625篇
  2021年   907篇
  2020年   817篇
  2019年   677篇
  2018年   569篇
  2017年   639篇
  2016年   582篇
  2015年   531篇
  2014年   877篇
  2013年   1008篇
  2012年   580篇
  2011年   675篇
  2010年   512篇
  2009年   470篇
  2008年   526篇
  2007年   515篇
  2006年   484篇
  2005年   414篇
  2004年   368篇
  2003年   307篇
  2002年   251篇
  2001年   175篇
  2000年   128篇
  1999年   102篇
  1998年   108篇
  1997年   101篇
  1996年   73篇
  1995年   56篇
  1994年   71篇
  1993年   61篇
  1992年   54篇
  1991年   50篇
  1990年   43篇
  1989年   49篇
  1988年   37篇
  1987年   48篇
  1986年   34篇
  1985年   29篇
  1984年   30篇
  1983年   18篇
  1982年   25篇
  1981年   11篇
  1980年   23篇
  1979年   8篇
  1978年   8篇
  1977年   8篇
  1976年   11篇
  1974年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
目的分别构建人乙型肝炎病毒(HBV)X蛋白、羧基端截断的中分子表面蛋白MHBst78、MHBst155编码基因的真核重组表达载体,以便进一步研究其转录激活功能及对宿主细胞信号传导通路的影响。方法设计合成3对寡核苷酸引物,以adr亚型HBV质粒pHBVDNA为模板,采用PCR法分别扩增HBVX基因、MHBst78与MHBst155编码基因片段;用HindⅢ,KpnⅠ双酶切HBVⅩ基因;用HindⅢ和BamHⅠ双酶切MHBst78与MHBst155编码基因片段后,分别定向插入到真核表达载体pcDNA3.1相应酶切位点,转化宿主菌JM109,提取质粒,分别用上述内切酶酶切及DNA测序鉴定重组质粒。结果酶切重组体显示所切下的片段大小均与预计相符,测序结果与文献报道序列及预计结果一致。结论成功构建了HBVX基因、羧基端截断的HBV中分子表面蛋白MHBst78、MHBst155编码基因的真核重组表达载体,为进一步研究HBV转录激活蛋白HBx、MHBst78MHBst155对宿主细胞信号转导通路的影响奠定基础。  相似文献   
32.
护理本科生关爱能力调查分析   总被引:3,自引:0,他引:3  
马芳  朱丹 《护理学杂志》2007,22(2):9-11
目的了解护理本科生关爱能力现状,为护理本科生关爱能力的培养提供依据。方法采用关爱能力评价表,对四川省4所医学院校579名护理本科生关爱能力进行问卷调查。结果护理本科生关爱能力评分为189.72±19.57,在各维度中耐心维度得分最高,勇气维度得分最低;不同性别、民族、是否独生子女关爱能力比较,差异无显著性意义(均P〉0.05);四年级护理本科生关爱能力评分显著高于二、三年级(均P〈0.05)。结论护理本科生关爱能力仍需提高,建议从实践关爱和课程设置等方面提高护理本科生的关爱能力。  相似文献   
33.
Two thousand nine hundred and ninety-four reports of OSHA-reportable occupational injury or illness cases in 1984 from member companies of a national trade association of semiconductor manufacturing firms were analyzed. The 37 participating manufacturing facilities represented 16 companies employing over 95,000 persons, or approximately one-third of the U.S. work force for this industry in 1984. The annual incidence rate for all reportable injuries and illnesses was 2.7 per 100 full-time employees (FTE) for men and 3.7 per 100 FTE for women. Strains, sprains, or dislocations were the most frequently reported incidents (N = 956 [31.9%]), followed by cuts, lacerations, punctures, scratches, and abrasions (N = 445 [14.9%]), and chemical burns (N = 401 [13.4%]). Increased work-loss days per case were associated with manufacturing sites that did not have an employee health clinic on the premises, with custodial occupations, and with female gender.  相似文献   
34.
BACKGROUND: Randomized studies demonstrate that laparoscopic appendectomy yields better results compared with open techniques. We sought to identify factors that determine an extended hospital stay among patients undergoing laparoscopic appendectomy. METHODS: This was a prospective study including 669 patients undergoing laparoscopic appendectomy. We analyzed variables that can predict the length of hospital stay. RESULTS: Of 669 patients undergoing laparoscopic appendectomy, 141 stayed in the hospital for > or = 5 days (Group 1), and 97 stayed in the hospital for < or = 1 day after surgery (Group 2). The univariate analysis demonstrated that fever (P<0.0001), nausea and vomiting (P=0.060), leukocytosis (P<0.0001), gangrened or perforated intraoperative appearance of the appendix (P<0.0001), and appendix position behind the ileocecal junction (P<0.001) were related to a longer hospital stay. The multivariate analysis through logistical regression showed that the factors independently and significantly associated with an extended hospital stay were presurgical fever, appendix position behind the ileocecal junction, and intraoperative gangrened or perforated appearance of the appendix. CONCLUSION: Fever, appearance, and position of the appendix are factors related to an extended hospital stay.  相似文献   
35.
A total of 103 fragments in the STR D12S391 locus were sequenced. 24 different alleles were found which can be grouped into 12 allelic classes based on the total number of repeats. The structure of this compund STR consists of blocks of (AGAT) and (AGAC) repeats with a consensus structure (AGAT)8–l7 (AGAC)6–10 (AGAT)0–1. Whereas shorter alleles only have (AGAT) repeats, > 225 bp alleles are more complex, having two motifs (AGAT) and (AGAC). Population data showed that this to be a highly polymorphic STR with a heterozygosity of 0.9. This fact together with its simple structure make this STR very suitable for forensic and genetic purposes.  相似文献   
36.
37.
目的 近年来产生了一些用于分析基因表达数据的聚类算法,却很少有关于评价聚类算法方法的研究。本研究的目的是尝试建立一个定量的评价基因表达数据聚类结果的方法。方法 本研究提供了一个系统的评价聚类结果的方法,利用我们提出的实验均方误差F值对几个常见的聚类算法进行比较。结果 利用F值对类质量的评价和利用已有的生物学知识对类进行分析的结果一致。结论 实验均方误差F值可以定量地评判用于基因表达数据的聚类算法。  相似文献   
38.
    
A knowledge-based alarm system for intensive care monitoring was designed, built, tested on-line, and evaluated. The system is a functional prototype of a highly specific patient monitor providing alarms on hypovolemia, hyperdynamic state, left ventricular failure and hypoventilation. These intelligent alarm functions aim to maintain the quality of patient monitoring even if nurses' attention is temporarily reduced or focused elsewhere. The alarm system has an electronic access to data available in a multichannel patient monitor and the patient data management system of the intensive care unit. Median filtering, trend estimation, and rule-based reasoning are applied when processing the measured variables and estimating the patient's state.  相似文献   
39.
Two programs have been developed to manage linkage analysis data. The first program, LABMAN, is a comprehensive laboratory data management system organizing pedigrees, blood DNA samples, DNA markers, Southern blot or polyacrylamide gels, autoradiographs, and marker-allele typings generated from these samples. Output includes mendelization checks for genetic incompatibilities in typings and formatted files ready for linkage analysis. LABMAN can also compress highly polymorphic allele systems into smaller allele systems facilitating analysis of large systems. The second program, LINKMAN, provides data management for lod score output from linkage analyses. It reads linkage analysis output files, calculates lod scores by family, associates lod scores with specific marker and family identifiers, and stores these data in a database where they can be combined with lod scores from previous analyses. LINKMAN easily incorporates any of a wide variety of genetic models. It produces formatted output of lod scores by user-specified criteria for reports or as ASCII files for input to other programs. If desired, tests of homogeneity of linkage across families can be run via the HOMOG program [Ott, 1991] and their output included in reports. The programs include features critical for conducting genome searches of complex diseases: They are easy-to-use, well-tested, and reliable. Data from multi-center investigations can be easily combined for analysis. Moreover, they include extensive error-checking capabilities, and they are specifically set up to protect blindness between laboratory workers and data analysts. LABMAN and LINKMAN are currently available free of charge under DOS. © 1994 Wiley-Liss, Inc.  相似文献   
40.
The F.I.P. (Financial Information Project) dietetic package allows the collection of basic patient data, which then can be processed to give valuable clinical and management information for use by all dietitians in a dietetic department. The advent of the Korner Reports (DHSS, 1984a) and their implementation highlighted the need to computerize certain aspects of data collection in dietetic departments. Within the West Midlands Regional Health Authority a group of dietitians worked with the Regional Management Services Department to adapt a community nursing system, F.I.P., for use by dietitians. The system was piloted for all paramedical services in 1987 with one health district (North Warwickshire) piloting the dietetic package. It is now used by a range of dietetic and paramedical departments. This paper outlines the system and its uses.  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