全文获取类型
收费全文 | 2490篇 |
免费 | 238篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 108篇 |
妇产科学 | 52篇 |
基础医学 | 351篇 |
口腔科学 | 56篇 |
临床医学 | 324篇 |
内科学 | 522篇 |
皮肤病学 | 15篇 |
神经病学 | 231篇 |
特种医学 | 138篇 |
外科学 | 334篇 |
综合类 | 58篇 |
预防医学 | 202篇 |
眼科学 | 49篇 |
药学 | 166篇 |
中国医学 | 2篇 |
肿瘤学 | 126篇 |
出版年
2022年 | 17篇 |
2021年 | 38篇 |
2019年 | 28篇 |
2018年 | 25篇 |
2017年 | 30篇 |
2016年 | 22篇 |
2015年 | 41篇 |
2014年 | 50篇 |
2013年 | 89篇 |
2012年 | 89篇 |
2011年 | 87篇 |
2010年 | 91篇 |
2009年 | 80篇 |
2008年 | 88篇 |
2007年 | 106篇 |
2006年 | 96篇 |
2005年 | 96篇 |
2004年 | 85篇 |
2003年 | 90篇 |
2002年 | 90篇 |
2001年 | 85篇 |
2000年 | 63篇 |
1999年 | 69篇 |
1998年 | 50篇 |
1997年 | 55篇 |
1996年 | 50篇 |
1995年 | 45篇 |
1994年 | 37篇 |
1993年 | 40篇 |
1992年 | 59篇 |
1991年 | 49篇 |
1990年 | 59篇 |
1989年 | 54篇 |
1988年 | 63篇 |
1987年 | 56篇 |
1986年 | 54篇 |
1985年 | 53篇 |
1984年 | 28篇 |
1983年 | 32篇 |
1982年 | 38篇 |
1981年 | 29篇 |
1980年 | 24篇 |
1979年 | 32篇 |
1978年 | 22篇 |
1977年 | 18篇 |
1976年 | 30篇 |
1975年 | 24篇 |
1973年 | 18篇 |
1970年 | 22篇 |
1969年 | 17篇 |
排序方式: 共有2740条查询结果,搜索用时 15 毫秒
91.
Richard Pollard Matthew Wagner Katherine Grichnik Brittany C. Clyne 《Current medical research and opinion》2017,33(12):2167-2171
Objective: To describe the incidence of difficult and failed intubations in obstetric patients during a 6 year period monitored by a quality assurance program together with American Society of Anesthesiologists Physical Status (ASA PS) scores, and obesity (body mass index >30?kg/m2).Methods: Following Institutional Review Board approval, data about obstetric patients who experienced unanticipated difficult or failed intubations from 2010 to 2015 was obtained from the quality assurance database of a large, community-based anesthesiology group practice. The database employs standardized definitions for difficult intubation (>3 laryngoscopic attempts by experienced providers) and failed intubation (inability to intubate leading to surgical airway or waking up the patient). ASA PS scores and comorbidities were also identified for obstetric general anesthetics using an internally developed quality assurance program, Quantum Clinical Navigation System.Results: There were 2802 obstetric general anesthetics in the database of which 1085 (38.7%) were deemed as emergencies. There were no cases of failed intubation and seven cases of unanticipated difficult intubations (1:400 cases, 0.25% of all obstetric general anesthetics, 95% confidence interval 0.1–0.5%), six of which occurred during emergency surgery. There was an increase in obesity (p?=?.003) and ASA PS (p?=?.02) over the period of the study. The incidence of difficult intubation was not found to be significantly changed (p?=?.68).Conclusions: Despite an increase in ASA PS score and obesity, there was no increase in the incidence of difficult intubation in obstetric patients. Limitations of the study include its retrospective design, and the small number of difficult intubation cases identified. 相似文献
92.
93.
94.
95.
Rationale and Objectives
The purpose of this pilot study was to establish the ability of dynamic contrast enhanced computed tomography (DCE‐CT) to detect changes in tumor blood flow (BF) and oxygenation induced by vasoactive substances in rats.Materials and Methods
Under ultrasound guidance, a fiber‐optic probe was guided into thigh tumors in eight rats and attached to an oxygenation/blood flow‐sensing device. A DCE‐CT sequence was acquired at the oxygen‐sensing probe tip during injection of iodinated contrast media. Group 1 rats (n = 6) were administered a vasodilator (hydralazine, 5 mg/kg i.v.) and group 2 rats (n = 2) were given physiologic saline in a similar volume. DCE‐CT was repeated at the probe tip after 30 min. BF in the whole tumor and at the probe tip were estimated pre‐ and post‐drug administration and the percentage change was calculated.Results
DCE‐CT defined significant differences between pre‐ and post‐drug BF in the whole tumor (p = 0.007) and at the probe tip (p = 0.03). Estimates of percentage change in BF in the whole tumor agreed with fiber‐optic measure of percentage change perfusion (r2 = 0.60; p = 0.02) and pO2 (r2 = 0.65; p = 0.02). Estimates of percentage change in BF at the probe tip agreed with fiber‐optic measures of percentage change in perfusion (r2 = 0.83; p = 0.001) and pO2 (r2 = 0.62; p = 0.02).Conclusions
Preliminary results indicate that DCE‐CT is capable of identifying alterations in tumor BF in rats. The percentage change in BF agrees with a validated estimate of tumor perfusion and oxygenation. This research technique may prove useful for assessment of tumor BF during combined chemotherapeutic and radiation therapy to improve outcome. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献96.
Brian J. Pollard 《Trends in Anaesthesia and Critical Care》2011,1(5-6):225-226
97.
Pollard RB 《AIDS (London, England)》2000,14(16):2421-2428
98.
Lund SS Tamow L Stehouwer CD 《药品评价》2008,5(8):380-380
在2型糖尿病患者中,反映炎症和内皮功能障碍的生物标志已经与心血管疾病和代谢调节联系起来。二甲双胍和促胰岛素分泌剂被证明有相同的抗高血糖作用。此研究比较了二甲双胍和促胰岛素分泌剂瑞格列奈在非肥胖的2型糖尿病患者的心血管疾病生物标志上的效能。 相似文献
99.
A J Pollard N Sreeram J G Wright S V Beath I W Booth D A Kelly 《Archives of disease in childhood》1995,73(2):147-150
The aim was to establish the prevalence of pulmonary embolism in 21 children (median age 12 months; range 5-132 months) with central venous lines in situ > 3 months (median 10 months; range 3-47). Twelve-lead electrocardiograms (ECGs) and echocardiograms were analysed in a retrospective study using ECG and echocardiographic criteria for pulmonary embolism-previously established and validated in adult patients- and standard paediatric ECG values as control data. Patients were scored as having definite (n = 7), probable (n = 5), or no pulmonary embolism (n = 9). Overall 57% of ECGs showed abnormalities compatible with pulmonary embolism. In two patients, serial ECGs obtained during an acute cardiorespiratory illness showed cumulative changes diagnostic of pulmonary embolism. Eight of 12 patients with abnormal ECGs had echocardiography; in seven of these (88%) the right ventricular end diastolic diameter was > 2SD above the mean value for age. Twelve of the patients included in this study have died; two died following an acute respiratory illness. There was postmortem evidence of pulmonary thromboembolism in both of the two children for whom necropsy information was available. The data suggest that pulmonary embolism is common in children who have central venous lines in situ for > 3 months. Serial studies are of value in some patients. Pulmonary embolism may compromise the long term survival of children with small bowel failure and preclude consideration for liver and small bowel transplantation. 相似文献
100.
Peter L. Devine Maree A. Duroux Rachel J. Quin Michael A. McGuckin Gloria J. Joy Bruce G. Ward Clifford W. Pollard 《Breast cancer research and treatment》1995,34(3):245-251
Summary This is the first comparison of the three mucin based tests CA15-3, CASA, and MSA, and the cytokeratin-related TPS assay in breast cancer. The mucin markers were superior to TPS in receiver-operator analysis, though no marker was of use in the diagnosis of malignancy due to low sensitivity. Using cutpoints that gave 95% specificity in benign disease (n = 83), corresponding sensitivities in pre-treatment breast cancer (n = 123: 13in situ, 54 stage I, 45 stage II, 4 stage III, 7 stage IV) were 17% (CA15-3), 16% (CASA), 13% (MSA), and 8% (TPS), with a strong relationship between marker levels and disease stage. These assays did not always detect the same patients, and the use of CA15-3 combined with CASA gave the highest sensitivity (23%), though this was not significantly better than the use of CA15-3 alone. Despite detecting similar antigens, these assays can show markedly different responses in some patients, indicating that one mucin-based test cannot be sub-stituted for another. 相似文献