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   82743篇
  免费   6590篇
  国内免费   185篇
耳鼻咽喉   637篇
儿科学   3253篇
妇产科学   2430篇
基础医学   10662篇
口腔科学   1114篇
临床医学   12368篇
内科学   15267篇
皮肤病学   1239篇
神经病学   7960篇
特种医学   1730篇
外国民族医学   38篇
外科学   7508篇
综合类   992篇
一般理论   163篇
预防医学   11731篇
眼科学   1181篇
药学   4828篇
中国医学   116篇
肿瘤学   6301篇
  2023年   668篇
  2022年   962篇
  2021年   2111篇
  2020年   1388篇
  2019年   2222篇
  2018年   2493篇
  2017年   1821篇
  2016年   2013篇
  2015年   2192篇
  2014年   2946篇
  2013年   4410篇
  2012年   6154篇
  2011年   6256篇
  2010年   3395篇
  2009年   2996篇
  2008年   5497篇
  2007年   5626篇
  2006年   5332篇
  2005年   5171篇
  2004年   4782篇
  2003年   4390篇
  2002年   4131篇
  2001年   799篇
  2000年   634篇
  1999年   729篇
  1998年   932篇
  1997年   699篇
  1996年   634篇
  1995年   615篇
  1994年   532篇
  1993年   504篇
  1992年   421篇
  1991年   404篇
  1990年   356篇
  1989年   343篇
  1988年   325篇
  1987年   269篇
  1986年   300篇
  1985年   325篇
  1984年   301篇
  1983年   293篇
  1982年   313篇
  1981年   344篇
  1980年   276篇
  1979年   168篇
  1978年   166篇
  1977年   145篇
  1976年   160篇
  1975年   130篇
  1974年   138篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
OBJECTIVE: This article 1) provides an overview of formal Health Sciences Teaching Scholars Programs as presented in medical education literature and 2) presents information about an innovative multidiscipline Teaching Scholars Program. METHOD: Health Sciences Teaching Scholars Programs and similar programs were reviewed in the medical education literature to identify similar and dissimilar characteristics. The WVU Teaching Scholars Program highlighted in this article is presented with a discussion of goals, objectives, target audiences, course length, session frequency, program topics, learning methods, and assessments of the programs. A summary of the WVU Teaching Scholars Program and two Teaching Scholars Programs at McGill University and the University of Toronto were presented at the Association for American Medical Colleges (AAMC) annual meeting in 2006 for input from the general medical education audience. RESULTS: Comparisons of Health Sciences Teaching Scholars Programs reveal that successful programs are uniquely shaped by their educational environments. Scholars report that they value learning new teaching methods and improving their educational careers. CONCLUSION: Teaching Scholars Programs are valuable for the development of enhancing both teaching and scholarship in Health Sciences Programs and must adapt to the uniqueness of their respective educational environments and must continue to nurture scholars beyond graduation.  相似文献   
84.
PURPOSE: To provide a model for assessing occupational therapy workforce needs by using a demand-based approach to determine current workforce status in the Northwest region. Regional information may have implications for addressing national occupational therapy service needs. METHOD: A questionnaire was sent to a proportional random sample of 234 facilities that hire occupational therapy practitioners. Data were collected in July-August 2003 using structured mailing and follow-up procedures. RESULTS: Response rate was 79%. Twenty-four percent reported occupational therapy vacancies and 11% occupational therapy assistant vacancies; 48% predicted an increase in occupational therapy positions in the next 2 years and 41% an increase in occupational therapy assistant positions. Sixty-three percent of respondents reported difficulty in hiring. DISCUSSION: This study identifies an occupational therapy workforce shortage in the Northwest. Management of a shortage is critical, for even short-term adjustments could lead to permanent changes in service provision. This study demonstrates the importance of current information on the status of the national workforce and serves as a model for future studies.  相似文献   
85.
86.
Bay K 8644 potentiated and augmented 5-hydroxytryptamine (5-HT)-induced contractions in the rabbit, isolated aorta preparation, as manifested in leftward shift and increase in the asymptote of 5-HT E/[A] (effect vs concentration) curves. The operational model of agonism (Black & Leff, 1983) was used to analyse this interaction and the concomitant effects of irreversible receptor alkylation by phenoxybenzamine. The competitive effects of spiperone in the presence and absence of Bay K 8644 were also examined. From these analyses it is concluded that Bay K 8644 elicits its potentiating effects by increasing the efficacy of 5-HT at the 5-HT2 receptor with no alteration in affinity. This is consistent with the known effect of Bay K 8644 of causing an increase in the functional concentration of plasmalemmal calcium channels coupled to the 5-HT2 receptors in this preparation. The positively co-operative shape of the 5-HT E/[A] curves obtained in the aorta and the quantitative nature of their potentiation by Bay K 8644 indicated that the coupling of 5-HT2 receptor occupancy to intracellular calcium concentration is linear and that the co-operativity resides in the subsequent relation between intracellular calcium and pharmacological effect. Bay K 8644 may serve as a probe for differentiating between the types of calcium channels that transduce 5-HT receptor-mediated effects in different systems. Such information would be useful in the classification of agonist interactions with 5-HT receptors.  相似文献   
87.
88.
The PFA-100 is a relatively new laboratory instrument, first described in 1995. There have since been numerous studies assessing its utility as a screening tool for platelet dysfunction and/or von Willebrand's disease (VWD). The PFA-100 displays variable sensitivity to different types of platelet disorders, as well as to antiplatelet medication (e.g. aspirin), with similar caveats for monitoring of primary haemostasis-promoting therapies in platelet dysfunction. There is therefore considerable uncertainty regarding its utility within this context, and we have accordingly performed an audit of usage among participants of the Royal College of Pathologists of Australasia Quality Assurance Program. Of 105 laboratories surveyed, 40 responded that they performed platelet function testing, with 26 (65%) further indicating they utilized the PFA-100. We report a wide variety of laboratory usage among these users, including numbers of tests performed [annual median (range) = 270 (15-6000)], sources of requests (clinical sources and localities), testing criteria and follow-up action. Most tests were completed within 4 h of collection, as recommended by the manufacturer, and most tests were performed as a replacement, or as a preliminary screen of platelet function (i.e. classical aggregation). Most abnormal findings, however, were attributed to antiplatelet medication such as aspirin.  相似文献   
89.
Chemoprevention refers to suppression or reversal of the carcinogenic process using pharmacologic or nutritional agents. Colorectal carcinogenesis is a protracted, multistep process that offers opportunities for prevention. Aspirin and selective cyclooxygenase-2 inhibitors (coxibs) have been evaluated for the prevention of sporadic adenoma recurrence. Aspirin was shown to reduce adenoma recurrence rates in patients with prior colorectal neoplasms; however, the optimal dosage remains unclear. Recent studies of coxibs indicate that these agents are effective in reducing sporadic adenoma recurrence, but chronic use can result in serious cardiovascular toxicity. These data underscore the need for chemopreventive agents with acceptable risk-to-benefit ratios. In this regard, nitric-oxide-releasing aspirin shows chemopreventive efficacy in preclinical models and holds promise for reduced toxicity in humans. Furthermore, ongoing chemoprevention trials are evaluating nutritional supplements, such as folic acid and selenium, and results are eagerly awaited.  相似文献   
90.
BACKGROUND: Acute pain is common after cardiac surgery and can keep patients from participating in activities that prevent postoperative complications. Accurate assessment and understanding of pain are vital for providing satisfactory pain control and optimizing recovery. OBJECTIVES: To describe pain levels for 5 activities expected of patients after cardiac surgery on postoperative days 1 to 6 and changes in pain levels after chest tube removal and extubation. METHODS: Adults who underwent cardiac surgery were asked to rate the pain associated with various types of activities on postoperative days 1 to 6. Pain levels were compared by postoperative day, activity, and type of cardiac surgery. Pain scores before and after chest tube removal and extubation also were analyzed. RESULTS: Pain scores were higher on earlier postoperative days. The order of overall pain scores among activities (P < .01) from highest to lowest was coughing, moving or turning in bed, getting up, deep breathing or using the incentive spirometer, and resting. Changes in pain reported with coughing (P = .03) and deep breathing or using the incentive spirometer (P = .005) differed significantly over time between surgery groups. After chest tubes were discontinued, patients had lower pain levels at rest (P = .01), with coughing (P = .05), and when getting up (P = .03). CONCLUSIONS: Pain relief is an important outcome of care. A comprehensive, individualized assessment of pain that incorporates activity levels is necessary to promote satisfactory management of pain.  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