全文获取类型
收费全文 | 222632篇 |
免费 | 4549篇 |
国内免费 | 213篇 |
专业分类
耳鼻咽喉 | 1871篇 |
儿科学 | 7727篇 |
妇产科学 | 3733篇 |
基础医学 | 22302篇 |
口腔科学 | 2344篇 |
临床医学 | 17800篇 |
内科学 | 39825篇 |
皮肤病学 | 1278篇 |
神经病学 | 20482篇 |
特种医学 | 10866篇 |
外国民族医学 | 3篇 |
外科学 | 37009篇 |
综合类 | 3143篇 |
现状与发展 | 1篇 |
一般理论 | 34篇 |
预防医学 | 21985篇 |
眼科学 | 3754篇 |
药学 | 13067篇 |
1篇 | |
中国医学 | 701篇 |
肿瘤学 | 19468篇 |
出版年
2023年 | 327篇 |
2022年 | 484篇 |
2021年 | 1253篇 |
2020年 | 665篇 |
2019年 | 1250篇 |
2018年 | 23192篇 |
2017年 | 18251篇 |
2016年 | 20425篇 |
2015年 | 2187篇 |
2014年 | 2687篇 |
2013年 | 3181篇 |
2012年 | 10553篇 |
2011年 | 24743篇 |
2010年 | 20850篇 |
2009年 | 13284篇 |
2008年 | 22472篇 |
2007年 | 25004篇 |
2006年 | 3818篇 |
2005年 | 5275篇 |
2004年 | 6128篇 |
2003年 | 7044篇 |
2002年 | 4906篇 |
2001年 | 693篇 |
2000年 | 704篇 |
1999年 | 568篇 |
1998年 | 742篇 |
1997年 | 594篇 |
1996年 | 442篇 |
1995年 | 433篇 |
1994年 | 376篇 |
1993年 | 297篇 |
1992年 | 263篇 |
1991年 | 281篇 |
1990年 | 318篇 |
1989年 | 286篇 |
1988年 | 260篇 |
1987年 | 218篇 |
1986年 | 191篇 |
1985年 | 206篇 |
1984年 | 210篇 |
1983年 | 180篇 |
1982年 | 222篇 |
1981年 | 164篇 |
1980年 | 231篇 |
1979年 | 119篇 |
1978年 | 117篇 |
1977年 | 87篇 |
1976年 | 86篇 |
1975年 | 87篇 |
1974年 | 95篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
We have previously reported the time trends, design and interventions in randomised controlled trials (RCTs) in cystic fibrosis (CF) from 1961 through 1997 [Cheng K, Smyth RL, Motley J, O'Hea U, Ashby D, Randomised controlled trials in cystic fibrosis (1966-1997) categorized by time, design, and intervention. Pediatr Pulmonol 2000, 29:1-7.]. We maintain an ongoing register of all RCTs and controlled clinical trials (CCTs) in CF and have noted that in the five years since 1997 there has been a 48% increase in published trials. We aimed to assess whether this increase has been associated with an improvement in design quality. All RCTs and CCTs from 1961-2002 were assessed. Two epochs were then compared, 1961-1997 and 1998-2002. For each trial we recorded the design, participant numbers and the intervention studied. 261 trials in 1998-2002 were compared with 544 trials in 1961-1997. Comparing the two epochs a similar proportion of trials were parallel, double-blind and placebo controlled; also the median number of participants was similar. In the later epoch 25% of trials were multicentre, compared with 11% previously. Whilst this recent increase in clinical trials in CF is welcome, this has not been associated with improvements in quality. The trend for an increasing proportion of trials to be multicentre is encouraging. There are however, still deficiencies in the design of clinical trials in CF. 相似文献
43.
44.
45.
Rènée du Toit Katherine Soong Garry Brian Jacqueline Ramke 《Optometry and vision science》2006,83(8):582-588
PURPOSE: The advantages of a focometer (FOCOMETER) over other methods of refraction for use in developing countries are that it is lightweight, compact, relatively inexpensive, fairly quick, and easy to use with minimal training. This clinical trial compared the repeatability, validity, and ease of use of the focometer with an autorefractor. METHODS: The refractive status of the right eye of 80 participants was determined with an autorefractor (Canon RK3). Three measurements were also taken with the focometer. RESULTS: The spherical equivalent (M) of the focometer was 0.25 D more positive than the autorefractor (p < 0.001) and 84% of measurements were within 0.75 D of the autorefractor. The autorefractor detected astigmatism in 91% (73) of the eyes, whereas the focometer identified only 32% (26). The design of the clock target restricts cylinder axis accuracy to the nearest 15 degrees . There was evidence of a learning effect for the focometer: the second and third measurements were more repeatable in the untrained group. There were no differences between the mean (1.03 +/- 2.28) and third focometer (-1.05 +/- 2.32) measurements (p = 0.34). However, using the third focometer measurement, 94% of participants had visual acuities of at least 6/12(-2). CONCLUSIONS: This study highlighted the focometer's restricted power range, inaccuracy of astigmatism and axis determination, and dependence on subject understanding and compliance. Therefore, in most clinical settings, the focometer would not be adequate for quantifying refractive error, but the focometer spherical equivalent was within acceptable limits of the autorefractor, and the visual acuity with lenses determined by the focometer indicates its potential usefulness in public health settings, especially where only spherical ready-made spectacles are dispensed. There may be more cost-effective ways to determine refractive error in these circumstances. A potentially important enhancement in focometer methodology that improves its ease of use was identified: use only the third measurement for each eye. 相似文献
46.
Susanne Ramsauer 《Zeitschrift für Psychodrama und Soziometrie》2007,6(2):293-302
Anliegen dieses Artikels ist, die besondere Qualit?t und Chance von Psychodramatischer Supervision zu beschreiben, und gleichzeitig
die Kompatibilit?t und fruchtbare Erg?nzung des Moreno’schen Ansatzes innerhalb des Formats Supervision innerhalb der Sozialen
Arbeit auf zuzeigen. Dies wird anhand von 2 ausgew?hlten Praxisbeispielen dargestellt. Die Handlungskompetenz von Supervisandinnen
und Supervisanden kann durch einfache psychodramatische Interventionen erweitert werden. Handlungshemmung wird überwunden,
Spontaneit?t und Kreativit?t kommen ins Laufen und er?ffnen Perspektiven. 相似文献
47.
48.
Debra L. Roter Richard M. Frankel Judith A. Hall David Sluyter 《Journal of general internal medicine》2006,21(1):28-34
Relationship-centered care reflects both knowing and feeling: the knowledge that physician and patient bring from their respective domains of expertise, and the physician’s and patient’s experience, expression, and perception of emotions during the medical encounter. These processes are conveyed and reciprocated in the care process through verbal and nonverbal communication. We suggest that the emotional context of care is especially related to nonverbal communication and that emotion-related communication skills, including sending and receiving nonverbal messages and emotional self-awareness, are critical elements of high-quality care. Although nonverbal behavior has received far less study than other care processes, the current review argues that it holds significance for the therapeutic relationship and influences important outcomes including satisfaction, adherence, and clinical outcomes of care. 相似文献
49.
Colin W. BINNS Dawn GILCHRIST Beth WOODS Michael GRACEY Jane SCOTT Hannah SMITH 《Nutrition & Dietetics》2006,63(1):8-14
Objective: To document the breastfeeding practices of Aboriginal mothers delivering in Perth. Design and methods: A cohort of mothers was followed from the time of delivery for six months to obtain details of infant feeding practices. Subjects: A total of 455 mothers delivered during the study period and were asked to participate. A total of 425 mothers completed the initial questionnaire. Setting: The study was undertaken in six public hospitals in Perth, Western Australia. Data analyses: The data were analysed using spss . Breastfeeding duration was calculated using Kaplan–Meier survival analysis. Main outcome measures: Breastfeeding initiation and duration. Results: The mean age of the Aboriginal mothers was 21.8 years (range 14–39 years, SD 5.32) and the average gestational age was 38.3 weeks. Almost 50% of the mothers in the study delivered by Caesarean section. At discharge from hospital 89.4% (CI 86.6–92.1) of mothers were breastfeeding, declining to 58.8% (CI 53.5–64.1) at six months. When compared with non‐Aboriginal mothers, the Aboriginal breastfeeding rates were higher than the non‐Aboriginal average breastfeeding rates, but lower than the highest socioeconomic group. Conclusions: The breastfeeding rates of Aboriginal mothers are higher than for other Australians. This is despite the low maternal age and level of education and the high rates of low‐birth‐weight infants and Caesarean section among this population. The World Health Organization recommendation for infant feeding is exclusive breastfeeding until six months, but less than one‐third of Aboriginal mothers achieved this recommendation. 相似文献
50.
杨娅 Thomas Bartel Loredana Latina Guido Caspari 王新房 Raimund Erbel 《华中科技大学学报(医学英德文版)》2002,22(2):158-163
Coronary flow reserve (CFR) has been used toassess coronary microcirculation and epicardial coro-nary stenoses[1— 3 ] . CFR is defined as the ratio ofcoronary flow under maximal coronary vasodilatationto coronary flow under resting conditions[4 ] .Whenthe cross- sectional area of epicardial coronary arteriesis constant,coronary flow velocity (CFV) ratios areequal to volume flow ratios.The most common method used clinically formeasuring CFVR is intracoronary Doppler flow(ICD) analysis re… 相似文献