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   4646篇
  免费   487篇
  国内免费   25篇
耳鼻咽喉   29篇
儿科学   223篇
妇产科学   76篇
基础医学   537篇
口腔科学   108篇
临床医学   562篇
内科学   881篇
皮肤病学   103篇
神经病学   405篇
特种医学   421篇
外科学   536篇
综合类   122篇
一般理论   1篇
预防医学   408篇
眼科学   111篇
药学   342篇
  1篇
中国医学   2篇
肿瘤学   290篇
  2021年   57篇
  2020年   42篇
  2019年   66篇
  2018年   85篇
  2017年   57篇
  2016年   68篇
  2015年   90篇
  2014年   101篇
  2013年   139篇
  2012年   211篇
  2011年   211篇
  2010年   148篇
  2009年   152篇
  2008年   156篇
  2007年   183篇
  2006年   188篇
  2005年   167篇
  2004年   167篇
  2003年   141篇
  2002年   139篇
  2001年   156篇
  2000年   144篇
  1999年   156篇
  1998年   140篇
  1997年   146篇
  1996年   141篇
  1995年   105篇
  1994年   114篇
  1993年   127篇
  1992年   79篇
  1991年   80篇
  1990年   63篇
  1989年   92篇
  1988年   85篇
  1987年   96篇
  1986年   89篇
  1985年   85篇
  1984年   54篇
  1983年   48篇
  1982年   41篇
  1981年   60篇
  1980年   40篇
  1979年   37篇
  1978年   33篇
  1977年   40篇
  1976年   47篇
  1974年   23篇
  1973年   25篇
  1971年   31篇
  1970年   21篇
排序方式: 共有5158条查询结果,搜索用时 109 毫秒
1.
Smoking cessation reduces the risk of death, improves recovery, and reduces the risk of hospital readmission. Evidence and policy support hospital admission as an ideal time to deliver smoking-cessation interventions. However, this is not well implemented in practice. In this systematic review, the authors summarize the literature on smoking-cessation implementation strategies and evaluate their success to guide the implementation of best-practice smoking interventions into hospital settings. The CINAHL Complete, Embase, MEDLINE Complete, and PsycInfo databases were searched using terms associated with the following topics: smoking cessation, hospitals, and implementation. In total, 14,287 original records were identified and screened, resulting in 63 eligible articles from 56 studies. Data were extracted on the study characteristics, implementation strategies, and implementation outcomes. Implementation outcomes were guided by Proctor and colleagues' framework and included acceptability, adoption, appropriateness, cost, feasibility, fidelity, penetration, and sustainability. The findings demonstrate that studies predominantly focused on the training of staff to achieve implementation. Brief implementation approaches using a small number of implementation strategies were less successful and poorly sustained compared with well resourced and multicomponent approaches. Although brief implementation approaches may be viewed as advantageous because they are less resource-intensive, their capacity to change practice in a sustained way lacks evidence. Attempts to change clinician behavior or introduce new models of care are challenging in a short time frame, and implementation efforts should be designed for long-term success. There is a need to embrace strategic, well planned implementation approaches to embed smoking-cessation interventions into hospitals and to reap and sustain the benefits for people who smoke.  相似文献   
2.
3.
4.
ABSTRACT

In many sexual assault cases, the most common evidence gathered comes in the form of intimate swabs. These swabs contain cells from both the female and male. In these cases the most common cell present is epithelial cells from the female with relatively few spermatozoa from the male. To produce an STR DNA profile suitable for an investigation, separation of the cell types is required to prevent a mixed profile that may complicate interpretation. While there are methods that can achieve this separation, they are labour intensive and have no guarantee of complete separation of the spermatozoa. Immunomagnetic bead separation techniques are being adapted from other scientific fields to be used in forensic biology to separate spermatozoa from mixed substrates. This study tested the binding of a Hyaluronidase PH-20 (SPAM1) antibody to spermatozoa in mixed cell samples that have been dried and stored for a short period of time. Fluorescently tagged antibodies were incubated with cellular mixtures and visualized using fluorescent microscopy. Successful binding of the antibodies to spermatozoa was observed in all samples. The SPAM1 antibody appears to be suitable for selection of spermatozoa and creates opportunities for linking with magnetic beads facilitate cell separation and DNA profiling.  相似文献   
5.
6.
Evidence suggests that despite high knowledge of family planning (FP), unwanted pregnancies and birth rates remain high among young Nigerians. There is a critical gap in understanding the nexus between exposure to FP information and contraception practices among this population. This study aimed to fill this gap and tested a pathway of the impact of media exposure to FP messages on modern contraceptive use. Data came from a 2018 cross-sectional baseline survey of young people aged 15–24 in three urban centers in Nigeria – Lagos, Kaduna, and Kano. This was part of an impact evaluation of a television-based drama designed to improve contraceptive use among young individuals. The study was limited to 777 young men and women who were sexually active. We found evidence of the mediation effect of media exposure to FP messages on partner discussion about FP, which in turn was associated with an increased likelihood of modern contraceptive use. Contraceptive self-efficacy also had positive associations with contraception. Our study elucidated a potential pathway through which media communication programs can significantly contribute to increased modern contraceptive use and underlined the importance of providing young people in Nigeria with opportunities to learn and practice obtaining and using contraception.  相似文献   
7.
8.
Australia provides abundant examples of continental-scale evolutionary radiations. The collision of two continental shelves around 30 Ma facilitated an influx of squamates and the subsequent squamate radiations resulted in high taxonomic diversity. The morphological disparity seen in these major squamate groups, however, remains underexplored. Here, we examine the major cranial proportions of over 1,000 specimens using 2D linear measurements to explicitly quantify the morphological disparity of Australian agamid lizards (Amphibolurinae) and compare it to that of agamid, acrodont, and iguanian clades from other parts of the world. Our results indicate the Australian Amphibolurinae have exceptionally high cranial disparity, and we suggest that this is linked to the relaxed selective environment that greeted the founders of Amphibolurinae when they first arrived in Australia. Anat Rec, 302:1536–1543, 2019. © 2019 American Association for Anatomy  相似文献   
9.
10.
BACKGROUND: The aim of this study was to investigate the influence of current hormonal contraceptive medication on periodontal health in young females. METHODS: Fifty women aged 20 to 35 years (mean +/- SD: 29.7 +/- 4.7 years) had a comprehensive periodontal examination. Current and previous contraceptive pill use was assessed by a questionnaire. Periodontal assessment included plaque index, gingival index, probing depth, and attachment level at six sites per tooth. The periodontal health of current pill users was compared to that of women not taking the pill. RESULTS: Forty-two percent of subjects were taking the contraceptive pill at the time of periodontal examination. Current pill users had deeper mean probing depths compared to non-users (3.3 mm versus 2.7 mm; P = 0.006) and more severe attachment loss (2.6 mm versus 1.7 mm; P = 0.015). Pill users had more sites with bleeding on probing (44.0% versus 31.1%; P = 0.017). CONCLUSION: Current users of oral contraceptives had poorer periodontal health.  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