全文获取类型
收费全文 | 3936篇 |
免费 | 277篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 72篇 |
儿科学 | 75篇 |
妇产科学 | 74篇 |
基础医学 | 490篇 |
口腔科学 | 98篇 |
临床医学 | 393篇 |
内科学 | 671篇 |
皮肤病学 | 38篇 |
神经病学 | 465篇 |
特种医学 | 439篇 |
外科学 | 658篇 |
综合类 | 60篇 |
一般理论 | 4篇 |
预防医学 | 273篇 |
眼科学 | 84篇 |
药学 | 225篇 |
1篇 | |
中国医学 | 1篇 |
肿瘤学 | 101篇 |
出版年
2023年 | 18篇 |
2022年 | 49篇 |
2021年 | 78篇 |
2020年 | 52篇 |
2019年 | 88篇 |
2018年 | 106篇 |
2017年 | 76篇 |
2016年 | 81篇 |
2015年 | 90篇 |
2014年 | 98篇 |
2013年 | 173篇 |
2012年 | 244篇 |
2011年 | 219篇 |
2010年 | 130篇 |
2009年 | 116篇 |
2008年 | 207篇 |
2007年 | 249篇 |
2006年 | 234篇 |
2005年 | 205篇 |
2004年 | 198篇 |
2003年 | 192篇 |
2002年 | 194篇 |
2001年 | 50篇 |
2000年 | 60篇 |
1999年 | 55篇 |
1998年 | 42篇 |
1997年 | 47篇 |
1996年 | 29篇 |
1995年 | 33篇 |
1994年 | 36篇 |
1993年 | 28篇 |
1992年 | 35篇 |
1991年 | 49篇 |
1990年 | 27篇 |
1989年 | 34篇 |
1988年 | 34篇 |
1987年 | 36篇 |
1986年 | 28篇 |
1985年 | 33篇 |
1984年 | 48篇 |
1983年 | 28篇 |
1982年 | 30篇 |
1981年 | 34篇 |
1980年 | 27篇 |
1979年 | 19篇 |
1978年 | 23篇 |
1977年 | 17篇 |
1976年 | 17篇 |
1974年 | 18篇 |
1973年 | 13篇 |
排序方式: 共有4222条查询结果,搜索用时 46 毫秒
81.
Shemesh AA Rasooly I Horowitz P Lemberger J Ben-Moshe Y Kachal J Danziger J Clarfield AM Rosenberg E 《Archives of gerontology and geriatrics》2008,47(1):63-77
To assess factors that affect the adoption of healthy lifestyles among a variety of active Israeli seniors, a survey was conducted in 2002 at the Peiluyada, a physical activity-oriented health fair for seniors held annually in Israel from 1995 to 2002. A multi-language, self-administered questionnaire, assessing predisposing factors, barriers and health-protective behaviors, was fielded to potential participants. Response rate at the event was 51%. Hebrew and Arabic speakers generally characterized their health as good to very good, while Russian speakers' health was rated only poor to fair. Over 80% engaged in regular physical activity, were satisfied with their diet, and conformed to international nutritional recommendations. Vaccination coverage against influenza (81%) and pneumocccocus (58%) was highest among Arabic speakers, and lowest among Russian speakers (33.5% and 12%, respectively). Higher age (> or =75 years) was significantly associated with receiving a vaccination against influenza. Major barriers to exercise included low motivation and poor physical health or disability. Health-related dietary restrictions were the leading nutritional barrier. Prominent barriers to vaccination included concerns about vaccine effectiveness (39%) and side effects (29%). Leading cues to action were a recommendation from one's doctor (67%) and from a healthcare worker (51%). 相似文献
82.
Remzi FH Gorgun E Bast J Schroeder T Hammel J Philipson E Hull TL Church JM Fazio VW 《Diseases of the colon and rectum》2005,48(9):1691-1699
PURPOSE This study was designed to evaluate the impact of childbirth on anal sphincter integrity and function, functional outcome, and quality of life in females with restorative proctocolectomy and ileal pouch-anal anastomosis.METHODS The patients who had at least one live birth after ileal pouch-anal anastomosis were asked to return for a comprehensive assessment. They were asked to complete the following questionnaires: the Short Form-36, Cleveland Global Quality of Life scale, American Society of Colorectal Surgeons fecal incontinence severity index, and time trade-off method. Additionally, anal sphincter integrity (endosonography) and manometric pressures were measured by a medical physician blinded to the delivery technique. Anal sphincter physiology also was evaluated with electromyography and pudendal nerve function by nerve terminal motor latency technique.RESULTS Of 110 eligible females who had at least one live birth after ileal pouch-anal anastomosis, 57 participated in the study by returning for clinical evaluation to the clinic and 25 others by returning the quality of life and functional outcome questionnaires. Patients were classified into two groups: patients who had only cesarean section delivery after ileal pouch-anal anastomosis (n = 62) and patients who had at least one vaginal delivery after ileal pouch-anal anastomosis (n = 20). The mean follow-up from the date of the most recent delivery was 4.9 years. The vaginal delivery group had significantly higher incidence of an anterior sphincter defect by anal endosonography (50 percent) vs. cesarean section delivery group (13 percent; P = 0.012). The mean squeeze anal pressure was significantly higher in the patients who had only cesarean section delivery (150 mmHg) after restorative proctocolectomy than patients who had at least one vaginal delivery (120 mmHg) after restorative proctocolectomy (P = 0.049). Quality of life evaluated by time trade-off method also was significantly better in the cesarean section delivery group (1) vs. vaginal delivery group (0.9; P < 0.001).CONCLUSIONS The risk of the sphincter injury and quality of life measured by time trade-off method are significantly worse after vaginal delivery compared with cesarean section in patients with ileal pouch-anal anastomosis. In the short-term, this does not seem to substantially influence pouch function or quality of life; however, the long-term effects remain unknown, thus obstetric concern may not be the only factor dictating the type of delivery in this group of patients. A planned cesarean section may eliminate these potential and factual concerns in ileal pouch-anal anastomosis patients.Podium presentation at the meeting of The American Society of Colon and Rectal Surgeons, Dallas, Texas, May 8 to 13, 2004. 相似文献
83.
Inflammatory mediators are induced by dietary glycotoxins,a major risk factor for diabetic angiopathy 总被引:15,自引:0,他引:15
Vlassara H Cai W Crandall J Goldberg T Oberstein R Dardaine V Peppa M Rayfield EJ 《Proceedings of the National Academy of Sciences of the United States of America》2002,99(24):15596-15601
Diet is a major environmental source of proinflammatory AGEs (heat-generated advanced glycation end products); its impact in humans remains unclear. We explored the effects of two equivalent diets, one regular (high AGE, H-AGE) and the other with 5-fold lower AGE (L-AGE) content on inflammatory mediators of 24 diabetic subjects: 11 in a 2-week crossover and 13 in a 6-week study. After 2 weeks on H-AGE, serum AGEs increased by 64.5% (P = 0.02) and on L-AGE decreased by 30% (P = 0.02). The mononuclear cell tumor necrosis factor-alphabeta-actin mRNA ratio was 1.4 +/- 0.5 on H-AGE and 0.9 +/- 0.5 on L-AGE (P = 0.05), whereas serum vascular adhesion molecule-1 was 1,108 +/- 429 and 698 +/- 347 ngml (P = 0.01) on L- and H-AGE, respectively. After 6 weeks, peripheral blood mononuclear cell tumor necrosis factor-alpha rose by 86.3% (P = 0.006) and declined by 20% (P, not significant) on H- or L-AGE diet, respectively; C-reactive protein increased by 35% on H-AGE and decreased by 20% on L-AGE (P = 0.014), and vascular adhesion molecule-1 declined by 20% on L-AGE (P < 0.01) and increased by 4% on H-AGE. Serum AGEs were increased by 28.2% on H-AGE (P = 0.06) and reduced by 40% on L-AGE (P = 0.02), whereas AGE low density lipoprotein was increased by 32% on H-AGE and reduced by 33% on L-AGE diet (P < 0.05). Thus in diabetes, environmental (dietary) AGEs promote inflammatory mediators, leading to tissue injury. Restriction of dietary AGEs suppresses these effects. 相似文献
84.
85.
Laura C. Saunders Chris S. Johns Neil J. Stewart Charlotte J. E. Oram David A. Capener Valentina O. Puntmann Charlie A. Elliot Robin C. Condliffe David G. Kiely Martin J. Graves Jim M. Wild Andy J. Swift 《Journal of cardiovascular magnetic resonance》2018,20(1):78
Background
Native T1 may be a sensitive, contrast-free, non-invasive cardiovascular magnetic resonance (CMR) marker of myocardial tissue changes in patients with pulmonary artery hypertension. However, the diagnostic and prognostic value of native T1 mapping in this patient group has not been fully explored. The aim of this work was to determine whether elevation of native T1 in myocardial tissue in pulmonary hypertension: (a) varies according to pulmonary hypertension subtype; (b) has prognostic value and (c) is associated with ventricular function and interaction.Methods
Data were retrospectively collected from a total of 490 consecutive patients during their clinical 1.5 T CMR assessment at a pulmonary hypertension referral centre in 2015. Three hundred sixty-nine patients had pulmonary hypertension [58?±?15 years; 66% female], an additional 39 had pulmonary hypertension due to left heart disease [68?±?13 years; 60% female], 82 patients did not have pulmonary hypertension [55?±?18; 68% female]. Twenty five healthy subjects were also recruited [58 ±4 years); 51% female]. T1 mapping was performed with a MOdified Look-Locker Inversion Recovery (MOLLI) sequence. T1 prognostic value in patients with pulmonary arterial hypertension was assessed using multivariate Cox proportional hazards regression analysis.Results
Patients with pulmonary artery hypertension had elevated T1 in the right ventricular (RV) insertion point (pulmonary hypertension patients: T1?=?1060?±?90 ms; No pulmonary hypertension patients: T1?=?1020?±?80 ms p <?0.001; healthy subjects T1?=?940?±?50 ms p <?0.001) with no significant difference between the major pulmonary hypertension subtypes. The RV insertion point was the most successful T1 region for discriminating patients with pulmonary hypertension from healthy subjects (area under the curve?=?0.863) however it could not accurately discriminate between patients with and without pulmonary hypertension (area under the curve?=?0.654). T1 metrics did not contribute to prediction of overall mortality (septal: p =?0.552; RV insertion point: p =?0.688; left ventricular free wall: p =?0.258). Systolic interventricular septal angle was a significant predictor of T1 in patients with pulmonary hypertension (p <?0.001).Conclusions
Elevated myocardial native T1 was found to a similar extent in pulmonary hypertension patient subgroups and is independently associated with increased interventricular septal angle. Native T1 mapping may not be of additive value in the diagnostic or prognostic evaluation of patients with pulmonary artery hypertension.86.
A critical review of knowledge on nurses with problematic substance use: The need to move from individual blame to awareness of structural factors
下载免费PDF全文
![点击此处可从《Nursing inquiry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Problematic substance use (PSU) among nurses has wide‐ranging adverse implications. A critical integrative literature review was conducted with an emphasis on building knowledge regarding the influence of structural factors within nurses' professional environments on nurses with PSU. Five thematic categories emerged: (i) access, (ii) stress, and (iii) attitudes as contributory factors, (iv) treatment policies for nurses with PSU, and (v) the culture of the nursing profession. Conclusions were that an overemphasis on individual culpability and failing predominates in the literature and that crucial knowledge gaps exist regarding the influence of structural factors on driving and shaping nurses' substance use. 相似文献
87.
Aims
Cataract surgery is one of the most common surgeries performed, but its overuse has been reported. The threshold for cataract surgery has become increasingly lenient; therefore, the selection process and surgical need has been questioned. The aim of this study was to evaluate the changes associated with cataract surgery in patient-reported vision-related quality of life (VR-QoL).Methods
A prospective cohort study was conducted. Consecutive patients referred to cataract clinics in an NHS unit in Scotland were identified. Those listed for surgery were invited to complete a validated questionnaire (TyPE) to measure VR-QoL pre- and post-operatively. TyPE has five different domains (near vision, distance vision, daytime driving, night-time driving, and glare) and a global score of vision. The influence of pre-operative visual acuity (VA) levels, vision, and lens status of the fellow eye on changes in VR-QoL were explored.Results
A total of 320 listed patients were approached, of whom 36 were excluded. Among the 284 enrolled patients, 229 (81%) returned the questionnaire after surgery. Results revealed that the mean overall vision improved, as reported by patients. Improvements were also seen in all sub-domains of the questionnaire.Conclusion
The majority of patients appear to have improvement in patient-reported VR-QoL, including those with good pre-operative VA and previous surgery to the fellow eye. VA thresholds may not capture the effects of the quality of life on patients. This information can assist clinicians to make more informed decisions when debating over the benefits of listing a patient for cataract extraction. 相似文献88.
89.
Metabolic myopathies: evaluation by graded exercise testing 总被引:3,自引:0,他引:3
Exertional muscle pain and fatigue are common complaints; some patients with these symptoms have a metabolic myopathy. We have performed graded exercise testing with analysis of expired ventilation on 13 individuals with various kinds of metabolic myopathies. Their results differed from normal and reflected the underlying biochemical abnormality. Patients with disorders of the mitochondrial electron transport chain demonstrated marked limitations in aerobic metabolism and a greatly reduced maximum oxygen consumption. During intense exertion, normal individuals increase carbon dioxide generation due to buffering of lactic acid. This did not occur in patients with McArdle disease, in whom the respiratory exchange ratio (carbon dioxide production/oxygen consumption) did not rise above 1.0 at maximum exercise. These results indicated a deficit in anaerobic metabolism. Pyruvate dehydrogenase complex allows pyruvate produced from carbohydrate metabolism to enter the citric acid cycle. Patients with this enzyme deficiency showed an initially normal pattern followed by an abrupt cessation in carbohydrate dependent aerobic metabolism at higher work loads. During high-intensity exercise, progressive anaerobic metabolism was not accompanied by additional oxygen consumption. Finally, results from a patient with carnitine palmitoyl transferase deficiency revealed an early dependence on carbohydrate metabolism. The ventilatory threshold occurred at a low percentage of maximal oxygen consumption, reflecting the limited availability of lipid substrates for aerobic metabolism. Detection of some muscle metabolic abnormalities can be made on small biopsy specimens. However, definitive diagnosis of the defect nearly always requires studies on fresh or frozen muscle tissue obtained by an open biopsy. The decision on how the tissue should be processed and which metabolic studies should be performed frequently needs to be made before the biopsy is obtained. Thus, a noninvasive method to initially characterize patients with potential metabolic disorders is useful. Exercise testing with expired gas analysis can indicate the presence of a metabolic myopathy and results can then be used to direct the appropriate biochemical evaluations. 相似文献
90.
Lee Emerson E. Gong Anna J. Gawande Rakhee S. Fishman Elliot K. Vadvala Harshna V. 《Emergency radiology》2022,29(2):263-279
Emergency Radiology - The purpose of our review is to discuss the role of CT angiography (CTA) in evaluating a variety of vascular complications in critically ill COVID-19 patients. The COVID-19... 相似文献