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   70832篇
  免费   5282篇
  国内免费   476篇
耳鼻咽喉   816篇
儿科学   1887篇
妇产科学   1547篇
基础医学   8940篇
口腔科学   1247篇
临床医学   7054篇
内科学   16046篇
皮肤病学   1388篇
神经病学   5591篇
特种医学   2327篇
外国民族医学   1篇
外科学   9843篇
综合类   1618篇
一般理论   48篇
预防医学   4829篇
眼科学   2325篇
药学   5276篇
  1篇
中国医学   365篇
肿瘤学   5441篇
  2023年   388篇
  2022年   629篇
  2021年   1566篇
  2020年   987篇
  2019年   1381篇
  2018年   1715篇
  2017年   1295篇
  2016年   1449篇
  2015年   1681篇
  2014年   2383篇
  2013年   3135篇
  2012年   4602篇
  2011年   4786篇
  2010年   2710篇
  2009年   2423篇
  2008年   4168篇
  2007年   4476篇
  2006年   4522篇
  2005年   4381篇
  2004年   4102篇
  2003年   3885篇
  2002年   3667篇
  2001年   1382篇
  2000年   1241篇
  1999年   1225篇
  1998年   845篇
  1997年   647篇
  1996年   608篇
  1995年   542篇
  1994年   502篇
  1993年   465篇
  1992年   667篇
  1991年   604篇
  1990年   579篇
  1989年   545篇
  1988年   499篇
  1987年   536篇
  1986年   461篇
  1985年   442篇
  1984年   474篇
  1983年   389篇
  1982年   428篇
  1981年   367篇
  1980年   345篇
  1979年   254篇
  1978年   251篇
  1977年   227篇
  1976年   222篇
  1975年   186篇
  1974年   155篇
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
51.
52.
53.
Objective: The study goal was to compare the laser spot size created using reflective and refractive micromanipulators with a CO2 laser and to determine the sensitivity of spot size to laser power. Study Design and Setting: A CO2 laser and operating microscope (400-mm focal length) was coupled to either a reflective (Cassegrain-like) or refractive micromanipulator. Laser spot size was determined by measuring the region of ablation created by laser irradiation of wood (dry tongue depressors), exposed photographic film, and agar gel using optical micrometry. Laser power varied from 0.5 to 20 W with pulse durations of 0.1 and 0.5 second. Results: The reflective micromanipulator demonstrated overall smaller spot sizes for a given laser power and lower incremental change in spot size with increasing power. The reflective design demonstrated less sensitivity to increases in laser power. Conclusions: Micromanipulator optical design can result in significant differences in laser spot size. The reflective device used in this study demonstrated less sensitivity to increasing laser power. (Otolaryngol Head Neck Surg 2002;126:593-597.)  相似文献   
54.
Reductions in substance use tend to coincide with marriage, as both may occur during emerging adulthood. During the transition to marriage, it is possible that one's spouse may be the influence that causes the reduction in substance use. Data on participants (N = 471 couples) for this report are taken from a longitudinal study of early marriage. The objective of the current analysis is to determine if having a spouse who uses marijuana is associated with a greater likelihood of one's own use. Additionally, we are interested in spousal influence and cessation. The findings support spousal influence. Husbands are more likely to start using marijuana if their wives use marijuana, but the reverse is not true. Husbands also are more likely to stop using if their spouses do not use. During the transition into marriage, the drug use of one spouse does affect the other. However, this influence appears to be unidirectional, with wives influencing their husbands more often.  相似文献   
55.
56.
Psoriasis is a chronic inflammatory condition that often requires life-long treatment. Conventional therapies have not fully met the needs of psoriatic patients, because of limited efficacy, adverse effects with cumulative use, and patient inconvenience. In the past decade, biologic immunotherapies have become accepted treatments for psoriasis as a result of perceived efficacy and safety on the part of patients and practitioners. However, most data on these medications come from relatively limited short-term trials. In this review, we will focus on the available long-term data on the efficacy of the biologic agents. We will emphasize the strengths and weakness of the available data of the biologic agents that are Food and Drug Administration (FDA)-approved for the treatment of moderate to severe psoriasis (alefacept, efalizumab, * etanercept, infliximab, and adalimumab), with the inclusion of a newer agent currently under FDA evaluation (ustekinumab).  相似文献   
57.
58.
59.
Background and objective  The purpose of this study is to assess whether Chinese children with high apnea–hypopnea index (AHI) are sleepier by a modified Epworth Sleepiness Scale (ESS). Materials and methods  Records were retrospectively reviewed. We included children who were between 3 and 12 years old, admitted for overnight polysomnogram because of suspected obstructive sleep apnea syndrome (OSAS). A modified ESS was used to assess excessive daytime sleepiness (EDS) of the children. Results  One hundred ninety-two Chinese children were included. Children with high AHI, defined as AHI > 5.0, were sleepier than children with AHI less than or equal to 5. After adjustment by age, gender, and obesity, children with high AHI remained significantly sleepier. Modified ESS was significantly correlated with AHI (rho = 0.124, 95% CI = 0.004–0.281). Modified ESS score of >8 was the best cutoff point with the sensitivity and specificity of 0.29 and 0.91, respectively. The odds ratio of children with modified ESS > 10 having high AHI was 4.231 (95%CI = 1.248 to 14.338) and children with modified ESS > 8 had the highest odds ratio, 4.295(95%CI = 1.66 to 11.1), of having high AHI. Conclusion   Chinese children with high AHI appear to be sleepier than children with low AHI. Children with suspected OSAS and high modified ESS, i.e., ESS > 8, had significantly higher odds ratio of having high AHI. Increased sleepiness is a specific but not a sensitive symptom in snoring children with high AHI. Screening for EDS in snoring children may help us identify those with high AHI and prioritize the management of those children. All authors worked and the study was carried out in Kwong Wah Hospital in Hong Kong. There was no conflict of interest and no specific source of funding for the study.  相似文献   
60.
Few cases in the history of epidemiology and public health are more famous than John Snow's investigation of a neighborhood cholera outbreak in the St. James, Westminster, area of London in 1854. In this study Snow is assumed to have proven that cholera was water rather than airborne through a methodology that became, and to a great extent remains, central to the science and social science of disease studies. And yet, Snow's work did not satisfy most of his contemporaries who considered his proof of a solely waterborne cholera interesting but unconvincing. Uniquely, this paper asks whether the caution of Snow's contemporaries was reasonable, and secondly, whether Snow might have been more convincing within the science of the day. The answers significantly alter our understanding of this paradigmatic case. It does so in a manner offering insights both into the origins of nineteenth century disease analysis and more generally, the relation of mapping in the investigation of an outbreak of uncertain origin. The result has general relevance—pedagogically and practically—in epidemiology, medical geography, and public 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