全文获取类型
收费全文 | 1045篇 |
免费 | 144篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 73篇 |
妇产科学 | 12篇 |
基础医学 | 156篇 |
口腔科学 | 47篇 |
临床医学 | 123篇 |
内科学 | 194篇 |
皮肤病学 | 20篇 |
神经病学 | 62篇 |
特种医学 | 149篇 |
外科学 | 101篇 |
综合类 | 46篇 |
预防医学 | 73篇 |
眼科学 | 38篇 |
药学 | 54篇 |
肿瘤学 | 50篇 |
出版年
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 9篇 |
2018年 | 25篇 |
2017年 | 12篇 |
2016年 | 27篇 |
2015年 | 29篇 |
2014年 | 37篇 |
2013年 | 53篇 |
2012年 | 36篇 |
2011年 | 28篇 |
2010年 | 55篇 |
2009年 | 56篇 |
2008年 | 30篇 |
2007年 | 56篇 |
2006年 | 30篇 |
2005年 | 31篇 |
2004年 | 21篇 |
2003年 | 22篇 |
2002年 | 24篇 |
2001年 | 23篇 |
2000年 | 21篇 |
1999年 | 17篇 |
1998年 | 45篇 |
1997年 | 46篇 |
1996年 | 46篇 |
1995年 | 38篇 |
1994年 | 28篇 |
1993年 | 34篇 |
1992年 | 8篇 |
1991年 | 17篇 |
1990年 | 10篇 |
1989年 | 27篇 |
1988年 | 19篇 |
1987年 | 16篇 |
1986年 | 23篇 |
1985年 | 22篇 |
1984年 | 9篇 |
1983年 | 16篇 |
1982年 | 7篇 |
1981年 | 13篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 14篇 |
1976年 | 18篇 |
1973年 | 8篇 |
1971年 | 5篇 |
1969年 | 6篇 |
1966年 | 6篇 |
排序方式: 共有1201条查询结果,搜索用时 15 毫秒
1.
2.
3.
Impact of Early Initiation of Enteral Nutrition on Survival During Pediatric Extracorporeal Membrane Oxygenation 下载免费PDF全文
Kristin C. Greathouse MS CPNP‐AC Kelly T. Sakellaris MS RD Dmitry Tumin PhD Jacob Katsnelson MD Joseph D. Tobias MD Don Hayes MD Jr. Andrew R. Yates MD 《JPEN. Journal of parenteral and enteral nutrition》2018,42(1):205-211
Introduction: Pediatric data related to safety, tolerance, and outcomes of enteral nutrition (EN) for patients requiring extracorporeal membrane oxygenation (ECMO) are lacking. The objectives of this study were to evaluate early nutrition status and timing of EN initiation on survival during pediatric ECMO. Methods: A single center institutional review board–approved retrospective chart review was performed on all pediatric patients requiring ECMO from October 2008 through December 2013. Demographics, ECMO variables, laboratory values, vasoactive inotropic score (VIS), and nutrition data on day 5 (d5) were collected. Patients receiving parenteral nutrition (PN) were compared with those receiving any EN on d5. Analyses were conducted to identify factors influencing survival to completion of ECMO and to discharge. Results: Forty‐nine patients aged 53 ± 76 months met inclusion criteria. Kaplan‐Meier curves demonstrated greater survival to discharge in patients receiving any EN, compared with only receiving PN (P = .031). EN on d5 of ECMO support (P = .040) and a higher percentage of daily energy intake achieved (P = .013) were protective, whereas a higher VIS was associated with increased mortality (P = .010). Multivariable analysis demonstrated EN was no longer associated with survival to discharge (P = .139), whereas energy intake (P = .021) and VIS (P = .013) remained significant. Conclusions: Pediatric patients who received nutrition that was closer to goal energy intake, as well as those who received any EN early during ECMO, had improved survival to hospital discharge. 相似文献
4.
Ashley C. Newell MD Kelly Davis CPNP‐PC/AC Li Wang MS David Bichell MD Mark A. Clay MD 《JPEN. Journal of parenteral and enteral nutrition》2018,42(1):49-55
Background
Underweight infants with single‐ventricle cardiac physiology have been shown to have increased morbidity, mortality, and resource utilization. The purpose of this study was to determine whether patients who were overweight, as defined by weight‐for‐length z score >90th percentile, were similarly at risk for increased resource utilization, as defined by mechanical ventilation hours (VHs) and intensive care unit length of stay (ICU LOS).Methods
We evaluated resource utilization for 109 patients from our institution who underwent bidirectional Glenn surgery from January 2010 to June 2015 and met prespecified inclusion criteria. Patients were divided into 3 groups: underweight (z score, <5th percentile), normal weight (z score, 5th–90th percentile), and overweight (z score, >90th percentile).Results
ICU LOS was longer in the overweight group (median, 18.5 days) when compared with the under‐ and normal‐weight groups (median LOS, 11 and 9 days, respectively) but did not reach statistical significance. VHs were also increased in the overweight group (median, 72 hours) when compared with the underweight (median, 27 hours) and normal weight (median, 25 hours) groups. This increase in VHs was statistically significant (P = .03).Conclusions
This study suggests that patients with single‐ventricle physiology who are overweight at the time of their bidirectional Glenn surgery may be at risk for increased resource utilization as compared with those who meet or fail to meet their caloric recommendations. These findings represent an underappreciated risk factor in this already‐vulnerable patient population, providing potential opportunity for intervention and improved outcomes. 相似文献5.
Validated numerical modeling of the effects of combined orthodontic and orthognathic surgical treatment on TMJ loads and muscle forces. 总被引:2,自引:0,他引:2
Jeffrey C Nickel Ping Yao Peter M Spalding Laura R Iwasaki 《American journal of orthodontics and dentofacial orthopedics》2002,121(1):73-83
Investigations of the changes in the mechanics of the craniomandibular system as a result of treatment have been limited by the lack of validated models of this system. The aims of this project were to (1) validate numerical model predictions of temporomandibular joint (TMJ) eminence morphology and muscle forces produced during molar biting and (2) use the validated models to calculate the changes in TMJ and muscle forces as a consequence of treatment involving orthognathic surgery. Ten volunteers participated; their combined orthodontic and orthognathic surgical treatments were completed. Three-dimensional anatomical data from each subject were used in computer models to predict the sagittal TMJ eminence morphology and joint and muscle forces for each subject, consistent with the neuromuscular objectives of minimizing joint loads and muscle effort. The actual shape of the eminence in each subject was measured with jaw tracking. Surface electromyographic recordings were a measure of the muscle forces involved in static molar biting. Model predictions were compared with measured data from the subjects for eminence shape (R(2) = 0.96) and for muscle activity ratios (R(2) = 0.98). The strength of these relationships validated the models for use in calculating changes in joint loads and muscle forces after treatment. The results suggested that the mechanics of the masticatory system are affected by the combined treatments. The TMJ loads increased in 8 subjects. The average increases in condylar and muscle forces were 4% relative to the applied bite force, but in 1 case the increases were up to 20%. Therefore, although average increases in the forces were small, some persons may experience biologically significant increases in joint and muscle forces as a result of treatment. 相似文献
6.
The purpose of this study was to determine the respective oral and nasal contributions to total respiration in patients scheduled for surgical corrections of nasal obstruction. The effect of anterior nares expansion and/or nasal decongestant administration on the nasal component of breathing was also examined in these patients. Although variability among subjects was demonstrated in the ratio of nasal respiration to total respiration, 25% of the "nasally-obstructed" patients were 100% nasal breathers and no patient had a nasal component less than 18% of total respiration. Great variability existed among the patients in their response to nares expansion and/or decongestant administration. Collectively, they demonstrated no significant mean increase in nasal respiration with nares expansion alone. The patients demonstrated an increase with administration of the decongestant and with decongestant combined with nares expansion. The latter condition resulted in an increase that was greater than with decongestant alone. The implication of this study is that the traditional diagnostic terms "mouth breathing" or "nasal obstruction" are not useful. They do not describe the type, location, or severity of an obstruction or the relative contribution of the nose and mouth to respiration. Many patients who experience symptoms or have signs of nasal obstruction can functionally compensate to maintain 100% nasal breathing. 相似文献
7.
Microbiological culture analysis of the tongue anaerobic microflora in subjects with and without halitosis 总被引:1,自引:0,他引:1
AC Donaldson D McKenzie MP Riggio PJ Hodge H Rolph A Flanagan J Bagg 《Oral diseases》2005,11(S1):61-63
Objective: Determination of the microflora present on the tongue dorsum of subjects with and without halitosis using conventional microbiological culture methods.
Methods: Twenty-one halitosis and 20 control patients were recruited using a strict clinical protocol. Samples were collected from the posterior dorsum of the tongue using a sterile brush. Each sample was vortex mixed for 30 s and serial 10-fold dilutions to 10−7 were carried out. Samples were plated onto fastidious anaerobe agar (FAA) and FAA enriched with vancomycin. These were incubated under anaerobic conditions for 10 days at 37°C. Strict anaerobes were identified by metronidazole sensitivity and bacteria were identified to genus level by a combination of colony morphology, Gram staining and biochemical and enzymatic tests (rapid ID 32 A).
Results: The predominant species in test and control groups were Veillonella sp. and Prevotella sp. Greater species diversity was found in the halitosis samples compared with controls. The halitosis samples contained an increased incidence of unidentifiable Gram-negative rods, Gram-positive rods and Gram-negative coccobacilli.
Conclusions: There was no obvious association between halitosis and any specific bacterial genus. The increased species diversity found in halitosis samples suggests that halitosis may be the result of complex interactions between several bacterial species. The role of uncultivable bacteria may also be important in contributing to this process. 相似文献
Methods: Twenty-one halitosis and 20 control patients were recruited using a strict clinical protocol. Samples were collected from the posterior dorsum of the tongue using a sterile brush. Each sample was vortex mixed for 30 s and serial 10-fold dilutions to 10
Results: The predominant species in test and control groups were Veillonella sp. and Prevotella sp. Greater species diversity was found in the halitosis samples compared with controls. The halitosis samples contained an increased incidence of unidentifiable Gram-negative rods, Gram-positive rods and Gram-negative coccobacilli.
Conclusions: There was no obvious association between halitosis and any specific bacterial genus. The increased species diversity found in halitosis samples suggests that halitosis may be the result of complex interactions between several bacterial species. The role of uncultivable bacteria may also be important in contributing to this process. 相似文献
8.
9.
10.