全文获取类型
收费全文 | 28375篇 |
免费 | 1867篇 |
国内免费 | 120篇 |
专业分类
耳鼻咽喉 | 429篇 |
儿科学 | 688篇 |
妇产科学 | 579篇 |
基础医学 | 4120篇 |
口腔科学 | 2164篇 |
临床医学 | 2226篇 |
内科学 | 5968篇 |
皮肤病学 | 742篇 |
神经病学 | 2544篇 |
特种医学 | 608篇 |
外科学 | 3250篇 |
综合类 | 96篇 |
一般理论 | 6篇 |
预防医学 | 2820篇 |
眼科学 | 469篇 |
药学 | 2135篇 |
中国医学 | 223篇 |
肿瘤学 | 1295篇 |
出版年
2023年 | 222篇 |
2022年 | 304篇 |
2021年 | 1132篇 |
2020年 | 719篇 |
2019年 | 967篇 |
2018年 | 1151篇 |
2017年 | 850篇 |
2016年 | 868篇 |
2015年 | 1078篇 |
2014年 | 1330篇 |
2013年 | 1570篇 |
2012年 | 2395篇 |
2011年 | 2505篇 |
2010年 | 1361篇 |
2009年 | 1042篇 |
2008年 | 1662篇 |
2007年 | 1720篇 |
2006年 | 1460篇 |
2005年 | 1270篇 |
2004年 | 1123篇 |
2003年 | 966篇 |
2002年 | 794篇 |
2001年 | 475篇 |
2000年 | 483篇 |
1999年 | 396篇 |
1998年 | 159篇 |
1997年 | 120篇 |
1996年 | 85篇 |
1995年 | 73篇 |
1994年 | 97篇 |
1993年 | 66篇 |
1992年 | 220篇 |
1991年 | 195篇 |
1990年 | 156篇 |
1989年 | 135篇 |
1988年 | 124篇 |
1987年 | 87篇 |
1986年 | 106篇 |
1985年 | 101篇 |
1984年 | 69篇 |
1983年 | 65篇 |
1982年 | 34篇 |
1981年 | 34篇 |
1980年 | 45篇 |
1979年 | 64篇 |
1978年 | 47篇 |
1973年 | 34篇 |
1969年 | 33篇 |
1968年 | 43篇 |
1966年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 26 毫秒
41.
42.
43.
Edwin D. Boudreaux PhD Brian L. Cruz MD Brigitte M. Baumann MD 《Academic emergency medicine》2006,13(7):795-802
Objectives: The authors reviewed the evidence on performance improvement methods for increasing emergency department (ED) patient satisfaction to provide evidence-based suggestions for clinical practice.
Methods: Data sources consisted of searches through MEDLINE, CINAHL, PSYCHINFO, Cochrane Library, and Emergency Medicine Abstracts and a manual search of references. Articles were included if they reported a performance improvement intervention targeting patient satisfaction in the ED setting. Articles on studies not conducted in the United States or that failed to provide enough details to allow critical evaluation of the study were excluded. Two authors used structured evaluation criteria to independently review each retained study.
Results: Nineteen articles met all selection criteria. Three studies found varying levels of support for multicomponent interventions, predominantly focused on implementation of clinical practice guidelines for specific presenting complaints and process redesign. Sixteen studies evaluated single-component interventions, with the following having at least one supportive study: using alternating patient assignment to provider teams rather than "zone"-based assignment, enhancing provider communication and customer service skills, incorporating information delivery interventions (e.g., pamphlets, video) that target patient expectations, using preformatted charts, and establishing ED-based observation units for specific conditions such as asthma and chest pain.
Conclusions: There is modest evidence supporting a range of performance improvement interventions for improving ED patient satisfaction. Further work is needed before specific, evidence-based recommendations can be made regarding which process changes are most effective. Recommendations are made for improving the quality of performance improvement efforts in the ED setting. 相似文献
Methods: Data sources consisted of searches through MEDLINE, CINAHL, PSYCHINFO, Cochrane Library, and Emergency Medicine Abstracts and a manual search of references. Articles were included if they reported a performance improvement intervention targeting patient satisfaction in the ED setting. Articles on studies not conducted in the United States or that failed to provide enough details to allow critical evaluation of the study were excluded. Two authors used structured evaluation criteria to independently review each retained study.
Results: Nineteen articles met all selection criteria. Three studies found varying levels of support for multicomponent interventions, predominantly focused on implementation of clinical practice guidelines for specific presenting complaints and process redesign. Sixteen studies evaluated single-component interventions, with the following having at least one supportive study: using alternating patient assignment to provider teams rather than "zone"-based assignment, enhancing provider communication and customer service skills, incorporating information delivery interventions (e.g., pamphlets, video) that target patient expectations, using preformatted charts, and establishing ED-based observation units for specific conditions such as asthma and chest pain.
Conclusions: There is modest evidence supporting a range of performance improvement interventions for improving ED patient satisfaction. Further work is needed before specific, evidence-based recommendations can be made regarding which process changes are most effective. Recommendations are made for improving the quality of performance improvement efforts in the ED setting. 相似文献
44.
Alfredo Marzano Silvia Gaia Valeria Ghisetti Silvia Carenzi Alberto Premoli Wilma Debernardi-Venon Carlo Alessandria Alessandro Franchello Mauro Salizzoni Mario Rizzetto 《Liver transplantation》2005,11(4):402-409
Hepatitis B virus (HBV) recurrence after liver transplantation is significantly reduced by prophylaxis with hepatitis B immune globulins (HBIG) or antiviral drugs in nonreplicating patients and by the combination of both drugs in replicating patients. However, the load of HBV DNA, which defines replicating status in patients undergoing liver transplantation, remains unclear. This study analyzes the correlation between the viral load, tested with a single amplified assay, at the time of liver transplantation, and the risk of hepatitis B recurrence in 177 HBV carriers who underwent transplantation in a single center from 1990 to 2002. Overall, HBV relapsed after surgery in 15 patients (8.5%) with a 5- and 8-year actuarial rate of recurrence of 8% and 21%, respectively. After liver transplantation hepatitis B recurred in 9% of 98 selected subjects treated only with immune globulins and in 8% of 79 viremic patients who received immune globulins and lamivudine (P = NS). A linear correlation was observed between recurrence and viral load at the time of surgery. In transplant patients with HBV DNA higher than 100,000 copies/mL, 200-99,999 copies/mL, and DNA undetectable by amplified assay, hepatitis B recurred in 50%, 7.5%, and 0% of patients, respectively. Overall, a viral load higher than 100,000 copies/mL at the time of liver transplantation was significantly associated with hepatitis B recurrence (P = .0003). In conclusion, spontaneous or antiviral-induced HBV DNA viral load at the time of surgery classifies the risk of HBV recurrence after liver transplantation and indicates the best prophylaxis strategy. 相似文献
45.
46.
Baruffi RL Mauri AL Petersen CG Felipe V Martins AM Cornicelli J Cavagna M Oliveira JB Franco JG 《Reproductive biomedicine online》2007,14(1):14-25
This study aims to compare the efficacy of recombinant LH (rLH) supplementation for ovarian stimulation in gonadotrophin-releasing hormone-antagonist protocol for IVF/intracytoplasmic sperm injection cycles. Search strategies included online surveys of databases. The fixed effects model was used for odds ratio (OR) and effect size (weighted mean difference, WMD). Five trials fulfilled the inclusion criteria. When the meta-analysis was carried out, advantages were observed for the LH supplementation protocol with respect to higher serum oestradiol concentrations on the day of human chorionic gonadotrophin administration P < 0.0001; WMD: 514, 95% CI 368, 660) and higher number of mature oocytes (P = 0.0098; WMD: 0.88, 95% CI 0.21, 1.54). However, these differences were not observed in the total amount of recombinant FSH (rFSH) administered, days of stimulation, number of oocyets retrieved, the clinical pregnancy rate per oocyte retrieval, the implantation rate and miscarriage rate. This result demonstrates that the association of rLH with rFSH may prevent any decrease in oestradiol after antagonist administration and that a significantly higher number of mature oocytes was available for laboratory work. Nevertheless, it failed to show any statistically significant difference in clinically significant end-points in IVF (implantation and pregnancy rates). Additional randomized controlled trials are needed to confirm these results further. 相似文献
47.
G T Keusch J R Cruz B Torun J J Urrutia H Smith A L Goldstein 《Journal of pediatric gastroenterology and nutrition》1987,6(2):265-270
The percentage of peripheral blood lymphocytes forming rosettes with sheep erythrocytes (E-rosettes) was determined in 33 severely malnourished Guatemalan children, and in two groups of clinically well but mildly growth retarded children from the same environment. Mean E-rosettes in the acutely ill patients was lower than the value observed in the mildly malnourished children, although there was considerable overlap between groups. These data differ from previously published studies of severely malnourished children from other parts of the world in that not all patients had decreased values for E-rosettes, in contrast to the uniform depression reported by others. As all patients were clinically similar, the results suggest that there may be specific nutrient defects associated with protein-energy malnutrition that particularly affect immune function. In addition, in vitro incubation of lymphocytes from the acutely malnourished children with the thymic factor, thymosin fraction 5, increased the percentage of E-rosettes in a dose-dependent fashion. These data suggest that immature, thymosin-responsive T cells are present in circulation. It is possible that in vivo thymosin administration may be beneficial for malnourished individuals. 相似文献
48.
R I Cruz D M Anderson E G Armstrong W R Moyle 《The Journal of clinical endocrinology and metabolism》1987,64(3):433-440
When hCG adsorbs to surfaces, including membranes from tissues that lack specific hCG receptors, it adsorbs with a particular orientation. Some sites on the alpha- and beta-subunits project away from the surface and can be detected with radiolabeled monoclonal antibodies. Other epitopes, which are located on a region on the hormone that presumably contacts the surface, lose their ability to bind antibody. Using antibodies specific for epitopes on hCG which remain exposed and can be detected when the hormone is adsorbed to rat brain homogenates, we found hCG or closely related substances bound to progestational decidual tissues. Immunologically reactive material adsorbed to the decidual tissue increased and decreased in parallel with the serum levels of hCG throughout pregnancy. Binding of labeled monoclonal antibody to substances similar or identical to hCG in other tissues, including placenta and fetal lung, but not red cells, also was identified. Unlike material adsorbed to decidual tissues, receptor-bound hCG was not recognized by any of our alpha-subunit-specific antibodies. This finding suggests either that the adsorbed hormone has a different orientation than receptor-bound hormone or that the adsorbed hormone has dissociated into subunits. These studies represent the first detection of nonreceptor binding of hCG or related molecules to tissues lacking receptors or presumed not to synthesize the hormone. The role of nonreceptor-bound hCG, if any, is unknown. Other than its effects on stimulation of luteal steroidogenesis during early pregnancy, the role of hCG during most of pregnancy has not been determined. Conceivably, the nonreceptor binding we identified is related to a role for hCG in pregnancy that is not associated with an action on the ovarian LH receptor. 相似文献
49.
Mário Martins Oliveira Nogueira da Silva Ana Teresa Timóteo Joana Feliciano Lídia de Sousa Sofia Santos Fernando Marques Rui Ferreira 《Revista portuguesa de cardiologia》2007,26(7-8):691-702
Atrial electrical remodeling plays a part in recurrence of atrial fibrillation (AF). It has been related to an increase in heterogeneity of atrial refractoriness that facilitates the occurrence of multiple reentry wavelets and vulnerability to AF. AIM: To examine the relationship between dispersion of atrial refractoriness (Disp_A) and vulnerability to AF induction (A_Vuln) in patients with clinical paroxysmal AF (PAF). METHODS: Thirty-six patients (22 male; age 55+/-13 years) with > or =1 year of history of PAF (no underlying structural heart disease--n=20, systemic hypertension--n=14, mitral valve prolapse--n=1, surgically corrected pulmonary stenosis--n=1), underwent electrophysiological study (EPS) while off medication. The atrial effective refractory period (AERP) was assessed at five different sites--high (HRA) and low (LRA) lateral right atrium, high interatrial septum (IAS), proximal (pCS) and distal (dCS) coronary sinus--during a cycle length of 600 ms. AERP was taken as the longest S1-S2 interval that failed to initiate a propagation response. Disp_A was calculated as the difference between the longest and shortest AERP. A_Vuln was defined as the ability to induce AF with 1-2 extrastimuli or with incremental atrial pacing (600-300 ms) from the HRA or dCS. The EPS included analysis of focal electrical activity based on the presence of supraventricular ectopic beats (spontaneous or with provocative maneuvers). The patients were divided into group A--AF inducible (n=25) and group B--AF not inducible (n=11). Disp_A was analyzed to determine any association with A_Vuln. Disp_A and A_Vuln were also examined in those patients with documented repetitive focal activity. Logistic regression was used to determine any association of the following variables with A_Vuln: age, systemic hypertension, left ventricular hypertrophy, left atrial size, left ventricular function, duration of PAF, documented atrial flutter/tachycardia and Disp_A. RESULTS: There were no significant differences between the groups with regard to clinical characteristics and echocardiographic data. AF was inducible in 71% of the patients and noninducible in 29%. Group A had greater Disp_A compared to group B (105+/-78 ms vs. 49+/-20 ms; p=0.01). Disp_A was >40 ms in 50% of the patients without A_Vuln and in 91% of those with A_Vuln (p=0.05). Focal activity was demonstrated in 14 cases (39%), 57% of them with A_Vuln. Disp_A was 56+/-23 ms in this group and 92+/-78 ms in the others (p=0.07). Using logistic regression, the only predictor of A_Vuln was Disp_A (p=0.05). CONCLUSION: In patients with paroxysmal AF, Disp_A is a major determinant of A_Vuln. Nevertheless, the degree of nonuniformity of AERP appears to be less important as an electrophysiological substrate for AF due to focal activation. 相似文献
50.
Marcelo Biscegli Jatene Estela Azeka Edmar Atik Arlindo Riso Carla Tanamati Miguel Barbero Marcial Sergio Almeida de Oliveira 《The Journal of heart and lung transplantation》2005,24(5):638-641
A 28-month-old boy, weighing 11 kg, with severe dilated cardiomyopathy, was transplanted on December 1995. Hypertension and supraventricular tachycardia were detected in the immediate post-operative period, with favorable outcome. After 5 months of clinically asymptomatic follow-up, a dilation in the ascending aorta was observed on routine echocardiogram. Nuclear magnetic resonance imaging (NMRI) confirmed an ascending aortic aneurysm, with a diameter of 38 mm. An operation was performed, a bovine pericardium patch was sutured with reconstruction of the aortic wall, excluding the aneurysm. Good recovery was obtained and the child was discharged on Day 7 postoperatively. A post-operative echocardiogram showed absence of the aortic aneurysm and good surgical results. Another NMRI was done 5 months later, showing an intact ascending aorta. After 64 months, the patients clinical condition was confirmed as normal by echocardiogram. Surgical treatment was successful and the positive results have been maintained. 相似文献