全文获取类型
收费全文 | 14862篇 |
免费 | 922篇 |
国内免费 | 72篇 |
专业分类
耳鼻咽喉 | 71篇 |
儿科学 | 549篇 |
妇产科学 | 348篇 |
基础医学 | 2081篇 |
口腔科学 | 270篇 |
临床医学 | 1442篇 |
内科学 | 3171篇 |
皮肤病学 | 371篇 |
神经病学 | 1477篇 |
特种医学 | 314篇 |
外科学 | 1514篇 |
综合类 | 85篇 |
一般理论 | 16篇 |
预防医学 | 1269篇 |
眼科学 | 322篇 |
药学 | 1019篇 |
中国医学 | 25篇 |
肿瘤学 | 1512篇 |
出版年
2024年 | 20篇 |
2023年 | 165篇 |
2022年 | 292篇 |
2021年 | 517篇 |
2020年 | 323篇 |
2019年 | 439篇 |
2018年 | 487篇 |
2017年 | 389篇 |
2016年 | 388篇 |
2015年 | 483篇 |
2014年 | 627篇 |
2013年 | 804篇 |
2012年 | 1258篇 |
2011年 | 1197篇 |
2010年 | 702篇 |
2009年 | 592篇 |
2008年 | 997篇 |
2007年 | 1006篇 |
2006年 | 958篇 |
2005年 | 865篇 |
2004年 | 830篇 |
2003年 | 770篇 |
2002年 | 624篇 |
2001年 | 73篇 |
2000年 | 63篇 |
1999年 | 95篇 |
1998年 | 110篇 |
1997年 | 96篇 |
1996年 | 86篇 |
1995年 | 65篇 |
1994年 | 54篇 |
1993年 | 61篇 |
1992年 | 48篇 |
1991年 | 39篇 |
1990年 | 22篇 |
1989年 | 26篇 |
1988年 | 26篇 |
1987年 | 22篇 |
1986年 | 21篇 |
1985年 | 34篇 |
1984年 | 28篇 |
1983年 | 20篇 |
1982年 | 17篇 |
1981年 | 12篇 |
1980年 | 18篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1973年 | 7篇 |
1972年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 468 毫秒
991.
Holland R Murata SS Silva MN Dezan Junior E Souza Vd Bernabé PF 《Journal of applied oral science : revista FOB》2004,12(3):223-226
The subject of this paper was to conduct an in vitro study of the coronal leakage after root canal filling and post space preparation. One hundred single-rooted human teeth had their crowns removed and the canals prepared and filled by the lateral condensation technique with gutta-percha points and the sealers CRCS and Endofill (a Grossman cement). After post space preparation, the remainder of the filling was protected or not with 1mm of a plug of the following materials: Coltosol, Super Bonder (cyanoacrylate-ester), CRCS and Endofill. After 24 hours in saline, the specimens were immersed in a 2% methylene blue solution in a vacuum environment for 24 hours. The teeth were then sectioned longitudinally, leakage was evaluated linearly and the obtained data were submitted to the Kruskal-Wallis test. The results with the two sealers studied were similar between themselves and worse (p<0.01) than the groups with a protector plug. The statistical analysis ordered the experimental groups from the best to the worst in the following way: a - Endofill-Super Bonder, CRCS-Super Bonder, CRCS-CRCS; b - Endofill-Endofill; c - Endofill-Coltosol, CRCS-Coltosol; d - Endofill, CRCS. 相似文献
992.
Mitchell MJ Powers SW Byars KC Dickstein S Stark LJ 《Journal of developmental and behavioral pediatrics : JDBP》2004,25(5):335-346
This study examined family functioning at mealtime, a context relevant to the management of cystic fibrosis (CF). Thirty-three families of children with CF and a control sample of 33 families of children without a chronic illness were assessed. Family functioning was rated during a videotaped dinner using the McMaster Mealtime Interaction Coding System (MICS), and mealtime behavioral problems were assessed using the Behavioral Pediatrics Feeding Assessment Scale (BPFAS). Ratings for families of children with CF were lower than for control families on overall functioning and five of six MICS dimensions (Communication, Interpersonal Involvement, Behavior Control, Affect Management, Roles). In families of children with CF, better family functioning was related to less frequently occurring mealtime behavioral problems (BPFAS); however, family functioning was not related to the child's weight status or the child's caloric intake. Data support that nutritional intervention may be maximized if dietary adherence is promoted in the context of positive parent-child and family interactions. 相似文献
993.
Management and outcome of children with skin and soft tissue abscesses caused by community-acquired methicillin-resistant Staphylococcus aureus 总被引:7,自引:0,他引:7
Lee MC Rios AM Aten MF Mejias A Cavuoti D McCracken GH Hardy RD 《The Pediatric infectious disease journal》2004,23(2):123-127
BACKGROUND: Although the epidemiology of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has been explored in many investigations, management of this emerging infection has not been well-studied. For non-methicillin-resistant Staphylococcus aureus skin and soft tissue abscesses, incision and drainage is generally adequate therapy without the use of antibiotics, but this has not been established for CA-MRSA. METHODS: Children presenting to Children's Medical Center of Dallas for management of skin and soft tissue abscesses caused by culture-proved CA-MRSA were prospectively followed. We analyzed data from the initial evaluation and from two follow-up visits that focused on the management and outcome of CA-MRSA infection. Retrospective chart review was performed 2 to 6 months after the initial visit. RESULTS: Sixty-nine children were identified with culture-proved CA-MRSA skin and soft tissue abscess. Treatment consisted of drainage in 96% of patients and wound packing in 65%. All children were treated with antibiotics. Five patients (7%) were prescribed an antibiotic to which their CA-MRSA isolate was susceptible before culture results were known. Four patients (6%) required hospital admission on the first follow-up; none of these patients had received an antibiotic effective against CA-MRSA. A significant predictor of hospitalization was having a lesion initially >5 cm (P = 0.004). Initial ineffective antibiotic therapy was not a significant predictor of hospitalization (P = 1.0). Of the 58 patients initially given an ineffective antibiotic and managed as outpatients, an antibiotic active against CA-MRSA was given to 21 (36%) patients after results of cultures were known. No significant differences in response were observed in those who never received an effective antibiotic than in those who did. CONCLUSIONS: Incision and drainage without adjunctive antibiotic therapy was effective management of CA-MRSA skin and soft tissue abscesses with a diameter of <5 cm in immunocompetent children. 相似文献
994.
Miller KA Elkind-Hirsch K Benson M Bergh P Drews M Scott RT 《Fertility and sterility》2004,81(1):191-193
OBJECTIVE: To compare the effectiveness and tolerability of two different 17-gauge follicle aspiration needles used in a large in vitro fertilization (IVF) program. DESIGN: Prospective, randomized single blinded study. SETTING: Private IVF center. PATIENT(S): Three hundred women undergoing IVF were randomly allocated at the time of oocyte retrieval to either the study needle (n = 151; follicle aspiration set [FAS] set) or the standard needle (n = 149; Echotip) used in the practice. Patients were blinded to the needle used.INTERVENTION(S): Transvaginal ultrasound-guided oocyte aspiration. MAIN OUTCOME MEASURE(S): Number of eggs retrieved/follicles visualized, retrieval time, mean amount of blood in the aspirate, egg damage, patient tolerance, physician acceptability, implantation, and pregnancy rate. RESULT(S): No differences were found in the number of eggs retrieved normalized to follicles visualized. Egg damage (4% vs. 4.2%), average blood in the aspirate (2.2 vs. 2.2), and retrieval time per egg (38 vs. 36 seconds) were similar with both needles. There were also no differences in pain or cramping scores (at 30 minutes and 24 hours after retrieval) or in the physicians' ratings of the two needles. The percentage of patients receiving an embryo transfer (ET), the implantation rate per embryo transfer, and the clinical pregnancy rate per embryo transfer were comparable for both needles. CONCLUSION(S): The FASs are equivalent. 相似文献
995.
The prognostic virtue of inflammatory markers during late-onset sepsis in preterm infants 总被引:1,自引:0,他引:1
Arnon S Litmanovitz I Regev R Lis M Shainkin-Kestenbaum R Dolfin T 《Journal of perinatal medicine》2004,32(2):176-180
AIM: Late-onset sepsis (occurring after the first three days of life) is a serious complication in preterm infants. In order to assess the possible prognostic virtues of the acute phase inflammatory response in the disease, we compared the inflammatory response of preterm infants who died within 72 hours (h) (fulminant sepsis) to infants who recovered from the disease (non-fulminant sepsis). METHODS: Of 42 preterm infants that were evaluated: 10 had fulminant sepsis and 32 non-fulminant sepsis. Acute phase inflammatory response markers-C-reactive protein (CRP), serum amyloid A (SAA), interleukin (IL)-6 levels and white blood cell (WBC) counts were measured at the first suspicion of LOS and after 8, 24 and 48 h. RESULTS: Small for gestational age (SGA) infants who were treated with fewer days of antibiotics characterized the fulminant sepsis group. The initial high levels of inflammatory markers were similar in both groups, but as early as 8 h after onset significantly lower levels of SAA, CRP and WBC counts were documented in the fulminant sepsis group. The inflammatory response remained low at 24 and 48 h in the fulminant sepsis group, while in the survivors, significantly increased inflammatory markers were measured. Decreases in the levels of the inflammatory markers preceded episodes of metabolic acidosis and arterial hypotension that were more common in the fulminant sepsis group. Infant mortality correlated inversely with SAA levels at 8 h and with CRP and WBC counts at 24 h after onset. CONCLUSION: SAA, CRP and WBC counts can be used as prognostic markers in LOS in preterm infants, with SAA being the earliest prognostic marker. 相似文献
996.
Salihu HM Shumpert MN Aliyu MH Alexander MR Kirby RS Alexander GR 《American journal of perinatology》2004,21(3):121-129
We set out to estimate the association between smoking among pregnant women aged at least 40 years and pregnancy outcome by analyzing singleton live births in the United States between 1995 and 1997. The study group consisted of deliveries to mothers aged 40 years and older with two maternal age categories (20 to 29 and 30 to 39 years) as control. Although risks varied with maternal age, smoking was associated with a higher-than-expected risk for infant mortality in all maternal age categories. The highest rate of infant mortality associated with smoking after adjusting for confounding was among mothers aged 20 to 29 (hazard ratio [HR], 1.49; 95% confidence interval [CI], 1.28 to 1.75), while the lowest was among pregnant mothers in the 40 and above age category (HR, 1.03; 95% CI, 0.87 to 1.23). In utero fetal demise was highest among older smoking mothers (>/=40 years) and declined with decreasing age (p for trend <0.0001). In conclusion, the relationship between maternal smoking and pregnancy outcomes is modified by the age of the mother. 相似文献
997.
BACKGROUND: The use of protocols for patients with ST-elevation myocardial infarction (MI) is growing, but no definite conclusion regarding the value of critical pathways in Europe has been drawn. HYPOTHESIS: The aim of this study was to investigate the impact of critical pathway on processes of care and outcome for patients presenting to the emergency department (ED) of a large urban European hospital because of possible ST-elevation MI. METHODS: Critical pathways for management of acute chest pain at our ED were developed in 1998 and have been revised every year. Accordingly, the records of all patients referred in 1997 to the ED because of chest pain (before pathway implementation) and in 2001 (after last pathway revision) were reviewed. An ST-elevation MI was diagnosed at ED in 520 of 5,066 (10.3%) patients with chest pain in 1997, and in 452 of 4,843 (9.3%) patients with chest pain in 2001. Patients were managed according to the ED cardiologists' decisions in 1997, whereas they entered the pathways for ST-elevation MI in 2001, with predefined criteria for diagnosis, thrombolysis, percutaneous coronary intervention, and admission to the coronary care unit. RESULTS: Comparison of treatment modalities disclosed that more patients were given thrombolysis in 1997 (49 vs. 16%, p<0.05), whereas in 2001 more patients were sent to primary angioplasty (63 vs. 11%, p<0.05). Also in 2001, patients more often received aspirin (90 vs. 61%, p<0.05) and intravenous beta blockers (60 vs. 35%, p<0.05) soon after arrival at the ED. Comparison between 1997 and 2001 revealed that admission rates to the coronary care unit (69 vs. 78%, NS) and cardiac wards were similar (19 vs. 10%, NS). Conversely, compared with 1997, patients hospitalized in 2001 had a shorter length of stay (12 +/- 5 vs. 18 +/- 6 days, p<0.05), as well as fewer major adverse coronary events (21 vs. 30%, p<0.05) and lower all-cause in-hospital mortality (12 vs. 20%, p<0.05). The quality of care indicators improved with time, as door-to-electrocardiogram interval (10 +/- 6 vs. 19 +/- 9 min, p<0.05), door-to-needle time (25 +/- 10 vs. 35 +/- 10 min, p<0.05), and door-to-balloon interval (70 +/- 15 vs. 99 +/- 20 min, p<0.05) were shorter in 2001 than in 1997. CONCLUSIONS: A critical pathway for ST-elevation MI at the ED increases the use of evidence-based treatment strategies and improves outcome and quality of care of patients presenting to a European hospital because of acute chest pain. 相似文献
998.
Alban JP Hopson MM Ly V Whyte J 《American journal of physical medicine & rehabilitation / Association of Academic Physiatrists》2004,83(2):131-7; quiz 138-41, 167
OBJECTIVE: To study methylphenidate's adverse effects and impact on vital signs within the adult traumatic brain injury population. DESIGN: Thirty-five adults with traumatic brain injury enrolled in a double-blind, placebo-controlled, 6-wk crossover study of methylphenidate, given in a dose of 0.3 mg/kg/dose, twice a day. Vital signs were taken by trained clinicians and research assistants. Participants filled out weekly questionnaires pertaining to the adverse effects. RESULTS: Poor appetite was the only adverse effect related to methylphenidate. Other adverse effects commonly associated with methylphenidate, such as insomnia, rapid heart rate, and anxiety, were not found to be significantly related to the medication. The average rise in mean arterial pressure on methylphenidate was 2.5 mm. Methylphenidate showed a stronger impact on pulse, with an average increase of 7 beats/min. Baseline vital signs did not predict the degree of increase on methylphenidate. CONCLUSION: Methylphenidate appears to be safe for the adult population with traumatic brain injury. However, because a few individuals experienced significant changes in vital signs and adverse effects, all patients should be monitored. 相似文献
999.
Effects of methylphenidate on attention deficits after traumatic brain injury: a multidimensional, randomized, controlled trial 总被引:2,自引:0,他引:2
Whyte J Hart T Vaccaro M Grieb-Neff P Risser A Polansky M Coslett HB 《American journal of physical medicine & rehabilitation / Association of Academic Physiatrists》2004,83(6):401-420
OBJECTIVE: To evaluate the effects of methylphenidate on a variety of aspects of attention, ranging from laboratory-based impairment measures to caregiver ratings and work productivity, in individuals after traumatic brain injury. DESIGN: A total of 34 adults with moderate to severe traumatic brain injury and attention complaints in the postacute phase of recovery were enrolled in a 6-wk, double-blind, placebo-controlled, repeated crossover study of methylphenidate, administered in a dose of 0.3 mg/kg/dose, twice a day. A wide range of attentional measures was gathered weekly, including computerized and paper-and-pencil tests of attention, videotaped records of individual work in a distracting environment, real-time observational scoring of attentiveness in a classroom environment, and caregiver and clinician rating scales of attentiveness. Participants also attempted to guess their drug condition each week. Data from the first ten participants were used for pilot purposes, to develop attentional factors for composite scoring, and to identify attentional dimensions suggestive of a treatment effect for independent replication. The remaining 24 participants' results were used to confirm potential treatment effects seen in the pilot sample, using Wilcoxon's signed-ranks test on composite factor scores and individual variables. RESULTS: A total of 54 dependent variables were reduced to 13 composite factors and 13 remaining individual variables. Of the 13 attentional factors, five showed suggestive treatment effects in the pilot sample. Of these, three showed statistically significant treatment effects in the replication sample: speed of information processing (effect sizes, -0.06 to 0.48; P < 0.001), attentiveness during individual work tasks (effect sizes, 0.15-0.62; P = 0.01), and caregiver ratings of attention (effect sizes, 0.44-0.50; P = 0.01). Of the individual variables, four showed suggestive treatment effects in the pilot sample, but only one showed significant treatment effects in the replication sample: reaction time before errors in the Sustained Attention to Response Task (effect size, 0.20; P = 0.03). No treatment-related improvement was seen in divided attention, sustained attention, or susceptibility to distraction. None of the variables showed suggestive or definite negative treatment effects. Effect sizes for those performance measures positively affected by methylphenidate were in the small to medium range and included both impairment and activity level measures. Improvements in processing speed did not seem to come at the expense of accuracy. CONCLUSIONS: Methylphenidate, at 0.3 mg/kg/dose, given twice a day to individuals with attentional complaints after traumatic brain injury, seems to have clinically significant positive effects on speed of processing, caregiver ratings of attention, and some aspects of on-task behavior in naturalistic tasks. Further research is needed to identify the optimal dose and to extend these findings to less carefully selected individuals. 相似文献
1000.
Fletcher M 《Nursing times》2004,100(19):30-31
More than eight million people in the UK have respiratory conditions and one in four people die from them. We appear to be facing a major paradox with regard to the management of respiratory disease in the UK. Although we have a wide range of diagnostic tests and effective treatments at our disposal, we do not appear to be making any impact on the morbidity and mortality of respiratory disease. Respiratory disease needs to be moved onto the 'must do' agenda. 相似文献