全文获取类型
收费全文 | 20499篇 |
免费 | 2344篇 |
国内免费 | 564篇 |
专业分类
耳鼻咽喉 | 259篇 |
儿科学 | 298篇 |
妇产科学 | 266篇 |
基础医学 | 1727篇 |
口腔科学 | 301篇 |
临床医学 | 5259篇 |
内科学 | 1686篇 |
皮肤病学 | 108篇 |
神经病学 | 1417篇 |
特种医学 | 1309篇 |
外科学 | 1983篇 |
综合类 | 3554篇 |
现状与发展 | 1篇 |
一般理论 | 3篇 |
预防医学 | 2567篇 |
眼科学 | 244篇 |
药学 | 1060篇 |
257篇 | |
中国医学 | 871篇 |
肿瘤学 | 237篇 |
出版年
2024年 | 133篇 |
2023年 | 548篇 |
2022年 | 1015篇 |
2021年 | 1302篇 |
2020年 | 1346篇 |
2019年 | 959篇 |
2018年 | 882篇 |
2017年 | 1000篇 |
2016年 | 871篇 |
2015年 | 835篇 |
2014年 | 1767篇 |
2013年 | 1996篇 |
2012年 | 1374篇 |
2011年 | 1323篇 |
2010年 | 1088篇 |
2009年 | 947篇 |
2008年 | 895篇 |
2007年 | 798篇 |
2006年 | 670篇 |
2005年 | 554篇 |
2004年 | 447篇 |
2003年 | 389篇 |
2002年 | 320篇 |
2001年 | 254篇 |
2000年 | 207篇 |
1999年 | 151篇 |
1998年 | 143篇 |
1997年 | 128篇 |
1996年 | 130篇 |
1995年 | 101篇 |
1994年 | 86篇 |
1993年 | 78篇 |
1992年 | 100篇 |
1991年 | 58篇 |
1990年 | 54篇 |
1989年 | 41篇 |
1988年 | 45篇 |
1987年 | 43篇 |
1986年 | 30篇 |
1985年 | 35篇 |
1984年 | 47篇 |
1983年 | 32篇 |
1982年 | 25篇 |
1981年 | 27篇 |
1980年 | 23篇 |
1979年 | 17篇 |
1978年 | 17篇 |
1977年 | 19篇 |
1975年 | 13篇 |
1971年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Donald B. Penzien PhD ; Frank Andrasik PhD ; Brian M. Freidenberg PhD ; Timothy T. Houle PhD ; Alvin E. Lake III PhD; Gay L. Lipchik PhD ; Kenneth A. Holroyd PhD ; Richard B. Lipton MD ; Douglas C. McCrory MD ; Justin M. Nash PhD ; Robert A. Nicholson PhD ; Scott W. Powers PhD ABPP ; Jeanetta C. Rains PhD ; David A. Wittrock PhD 《Headache》2005,45(S2):S110-S132
Guidelines for design of clinical trials evaluating behavioral headache treatments were developed to facilitate production of quality research evaluating behavioral therapies for management of primary headache disorders. These guidelines were produced by a Workgroup of headache researchers under auspices of the American Headache Society. The guidelines are complementary to and modeled after guidelines for pharmacological trials published by the International Headache Society, but they address methodologic considerations unique to behavioral and other nonpharmacological treatments. Explicit guidelines for evaluating behavioral headache therapies are needed as the optimal methodology for behavioral (and other nonpharmacologic) trials necessarily differs from the preferred methodology for drug trials. In addition, trials comparing and integrating drug and behavioral therapies present methodological challenges not addressed by guidelines for pharmacologic research. These guidelines address patient selection, trial design for behavioral treatments and for comparisons across multiple treatment modalities (eg, behavioral vs pharmacologic), evaluation of results, and research ethics. Although developed specifically for behavioral therapies, the guidelines may apply to the design of clinical trials evaluating many forms of nonpharmacologic therapies for headache. 相似文献
32.
Objective: This pilot study was intended to test whether a training protocol improved validity of odor judges (OJs), with or without experience, and whether odorant types differed in error proneness.
Methods: The OJs (four experienced, two inexperienced) completed a 4-phase training protocol based on the American Society of Testing and Materials standards (ASTM): (i) introduction to sensory scales, n-butanol reference, sniffing techniques; (ii) pretraining measurements; 20 samples of varying intensities of four unpleasant and three pleasant odorants; (iii) exercises assessing quality, intensity, ranking, and matching; and (iv) post-training measurements.
Main outcome measures: Subjects' intensity scores were analyzed as the absolute difference from the 'true' intensity (ASTM n-butanol standard) using repeated measures ANOVA.
Results: Training significantly ( P = 0.02) reduced OJ errors. Experienced and novice judges did not differ in average errors ( P = 0.99), or in improvement in error from pre- to post-training ( P = 0.94). Improvement was consistent from pre- to post-training for all odorants except dimethylsulfide for which errors worsened ( P = 0.01). Unpleasant and pleasant odorants differed ( P = 0.006) in error. After removing water the effects of water control scores from the pleasant odorants, the difference was not significant ( P = 0.26).
Conclusions: The OJs improved in their ability to assess odor intensity irrespective of previous experience. Training is recommended for all OJs prior to research trials. 相似文献
Methods: The OJs (four experienced, two inexperienced) completed a 4-phase training protocol based on the American Society of Testing and Materials standards (ASTM): (i) introduction to sensory scales, n-butanol reference, sniffing techniques; (ii) pretraining measurements; 20 samples of varying intensities of four unpleasant and three pleasant odorants; (iii) exercises assessing quality, intensity, ranking, and matching; and (iv) post-training measurements.
Main outcome measures: Subjects' intensity scores were analyzed as the absolute difference from the 'true' intensity (ASTM n-butanol standard) using repeated measures ANOVA.
Results: Training significantly ( P = 0.02) reduced OJ errors. Experienced and novice judges did not differ in average errors ( P = 0.99), or in improvement in error from pre- to post-training ( P = 0.94). Improvement was consistent from pre- to post-training for all odorants except dimethylsulfide for which errors worsened ( P = 0.01). Unpleasant and pleasant odorants differed ( P = 0.006) in error. After removing water the effects of water control scores from the pleasant odorants, the difference was not significant ( P = 0.26).
Conclusions: The OJs improved in their ability to assess odor intensity irrespective of previous experience. Training is recommended for all OJs prior to research trials. 相似文献
33.
34.
护理本科生双导师制带教模式的实践 总被引:4,自引:2,他引:2
目的 探索适合护理本科生的临床带教模式.方法 将2001级和2000级护理本科生分为实验组(n=24)和对照组(n=38),对照组给予传统带教模式带教,实验组采用双导师制带教模式,即每名学生在临床实习期间,由1名临床专科导师负责其本科室专科知识方面的指导,1名全程导师负责其实习全过程的督导及检查工作,护理部在学生实习结束前进行带教满意率测评及实习效果评价,并与对照组进行比较.结果 两组对医院带教很满意率、学生护理理论、操作技能考核成绩、论文书写优良率比较,差异有显著性意义(均P<0.01).结论 双导师制可提高带教质量,是受学生好评和欢迎的带教模式. 相似文献
35.
耐热锻炼对人体热暴露时血浆丙二醛和中分子物质含量的影响 总被引:1,自引:0,他引:1
本文报告热习服对血浆丙二醛和中分子物质含量的影响。15名健康男子,平均年龄21.8±0.7岁,于平均气温27.3±1.2℃负重行军90min,2周内共锻炼11次(天)。标准热暴露试验对比表明获得了热习服,肛温和心率增值大大降低(P<0.01和P<0.05)。锻炼期前、后标准试验时血浆丙二醛含量降幅分别为29.4%(P<0.01)和30.1%(P<0.01),而中分子物质含量增幅分别为6.3%(P<0.05)和9.2%(P<0.01)。热前、后血浆丙二醛含量较锻炼期前仅分别降低5.5和6.5%(P>0.05),而中分子物质含量分别降低18.3和16.1%(P<0.01),可见,热习服后血浆丙二醛和中分子物质含量没有同步降低。 相似文献
36.
Summary Eight men (20–23 years) weight trained 3 days week–1 for 19 weeks. Training sessions consisted of six sets of a leg press exercise (simultaneous hip and knee extension and ankle plantar flexion) on a weight machine, the last three sets with the heaviest weight that could be used for 7–20 repetitions. In comparison to a control group (n = 6) only the trained group increased (P<0.01) weight lifting performance (heaviest weight lifted for one repetition, 29%), and left and right knee extensor cross-sectional area (CAT scanning and computerized planimetry, 11%, P<0.05). In contrast, training caused no increase in maximal voluntary isometric knee extension strength, electrically evoked knee extensor peak twitch torque, and knee extensor motor unit activation (interpolated twitch method). These data indicate that a moderate but significant amount of hypertrophy induced by weight training does not necessarily increase performance in an isometric strength task different from the training task but involving the same muscle group. The failure of evoked twitch torque to increase despite hypertrophy may further indicate that moderate hypertrophy in the early stage of strength training may not necessarily cause an increase in intrinsic muscle force generating capacity. 相似文献
37.
The effects of training, immobilization and remobilization on musculoskeletal tissue 总被引:2,自引:0,他引:2
P. Kannus L. Jozsa P. Renström M. Järvinen M. Kvist M. Lehto P. Oja I. Vuort 《Scandinavian journal of medicine & science in sports》1992,2(4):164-176
Compared with the knowledge on immobilization, the effects of remobilization on musculoskeletal tissues have not been well established. What is sure is that remobilization and rehabilitation of any component of the musculoskeletal tissues require much more time than the time needed to cause the immobilization atrophy. With intensive rehabilitation, the functional properties of skeletal muscles can be improved significantly even years after the injury and following immobilization, but no study has shown whether full recovery is possible and whether these rehabilitated muscles are able to respond normally to further training. Experimental studies have given evidence that slow-twitch muscle fibres have better capacity for recovery than fast-twitch fibres, most likely due to better circulation and higher protein turnover. Also evidence has been given that fibre regeneration is possible through satellite cell activation and myotube formation. Very little is known, however, about the effects of age, gender or the level of preimmobilization muscle performance on the restoration capacity. Also the fate of the marked structural changes (for example, connective tissue accumulation) induced by immobilization is unknown. Tendon and ligament tissues are likely to respond appropriately to remobilization, resulting in acceleration of collagen synthesis and fibril neoformation. However, there is a strong suspicion that remobilized tendons and ligaments will not achieve all the biochemical and biomechanical properties of their healthy counterparts. Specifically, the amount of weak type III collagen has been shown to be overrepresented in these tissues instead of mature, strong type I collagen. It is not known whether this is an important risk factor for ruptures during later activity. The effects of remobilization on muscle-tendon junction and proprioceptive organs are not known. It would not be surprising if the serious structural changes induced by immobilization were unrestorable. In the literature dealing with immobilization and remobilization, cartilage degeneration is always a major concern, because not only too strenuous training or immobilization, but also unskilful remobilization may activate this process leading finally to osteoarthrosis. Bone may be one of the best components of musculoskeletal tissues to respond to remobilization, probably because the immobilization atrophy of bone is largely quantitative (osteoporosis) only. The prerequisites for bony recovery are that the follow-up time is long enough (months) and that immobilization has not exceeded about 6 months, the time limit between active and inactive (irreversible) osteoporosis. Prevention of the atrophying effects of immobilization can be very successful if performed properly. According to present knowledge, there are many methods for the purpose, including preimmobilization training early, controlled mobilization; optimal positioning of the immobilized joint; muscular training during immobilization; early weightbearing; exercise with the nonimmobilized extremity; and electrical stimulation. Lots of education and information will be needed, however, before these methods are deeply rooted in the daily routines of the attending physicians, physical therapists, athletic trainers and other persons involved in the treatment of musculoskeletal problems. 相似文献
38.
心绞痛PTCA术后患者以步行为主的康复训练 总被引:4,自引:0,他引:4
14例不稳定性心绞痛患者,男性12例,女性2例,平均年龄55岁,均因药物治疗无效而进行PTCA治疗。总计16个血管段、前降支9段,回旋支4段,右冠状动脉3段。术后执行以步行为主要内容的一周康复训练程度,全部病例均顺利完成,表明以步为主的非监护康复训练对不稳定性心绞痛PTCA术后和是安全可行的。 相似文献
39.
40.