全文获取类型
收费全文 | 558篇 |
免费 | 21篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 25篇 |
妇产科学 | 1篇 |
基础医学 | 54篇 |
口腔科学 | 4篇 |
临床医学 | 71篇 |
内科学 | 100篇 |
皮肤病学 | 9篇 |
神经病学 | 29篇 |
特种医学 | 113篇 |
外科学 | 71篇 |
综合类 | 15篇 |
预防医学 | 30篇 |
眼科学 | 23篇 |
药学 | 21篇 |
中国医学 | 4篇 |
肿瘤学 | 23篇 |
出版年
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 8篇 |
2019年 | 2篇 |
2018年 | 8篇 |
2017年 | 1篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 13篇 |
2013年 | 19篇 |
2012年 | 8篇 |
2011年 | 19篇 |
2010年 | 26篇 |
2009年 | 14篇 |
2008年 | 26篇 |
2007年 | 27篇 |
2006年 | 33篇 |
2005年 | 27篇 |
2004年 | 22篇 |
2003年 | 28篇 |
2002年 | 15篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 12篇 |
1998年 | 21篇 |
1997年 | 20篇 |
1996年 | 27篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 15篇 |
1988年 | 22篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 13篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 3篇 |
排序方式: 共有594条查询结果,搜索用时 15 毫秒
31.
Tarasów E Wiercińska-Drapało A Jaroszewicz J Siergiejczyk L Orzechowska-Bobkiewicz A Prokopowicz D Walecki J 《Acta radiologica (Stockholm, Sweden : 1987)》2004,45(8):803-809
Purpose: To evaluate proton magnetic resonance spectroscopy (1H MRS) features in order to assess hepatocellular activation in chronic hepatitis C and human immunodeficiency virus/hepatitis C (HIV/HCV) co-infected patients. Material and Methods: Liver in vivo 1H MR spectra were obtained in 14 patients with hepatitis C virus infection (HCV), 20 HIV/HCV co-infected individuals, and 24 healthy volunteers. Resonances of lipids, glutamine/glutamate (Glx), phosphomonoesters (PME), glycogen/glucose (Glc) were assessed and metabolite ratios to total lipids (TL) were calculated. Results: A significant increase in Glx/TL and PME/TL was observed in the HCV group as compared to healthy individuals. Patients with HIV and HCV co-infection had a further increase of all metabolite ratios. Changes in metabolite ratios were due to both the increase in particular metabolite contents and to the decrease in lipid levels. HIV/HCV-infected patients treated with highly active anti-retroviral therapy (HAART) showed elevated PME and Glx levels and significantly decreased TL compared to patients not undergoing anti-retroviral treatment. Conclusions: Our findings suggest clinical usefulness of liver 1H MR spectroscopy in detecting even slight disturbances in liver metabolism. 相似文献
32.
33.
34.
Measurement of renal anatomy for prediction of lower-pole caliceal stone clearance: reproducibility of different parameters 总被引:3,自引:0,他引:3
Knoll T Musial A Trojan L Ptashnyk T Michel MS Alken P Köhrmann KU 《Journal of endourology / Endourological Society》2003,17(7):447-451
BACKGROUND AND PURPOSE: The architecture of the lower renal pole seems to have a considerable influence on caliceal stone clearance after different therapeutic modalities. The published data are partially inconsistent, and publications on reproducibility are completely lacking. The aim of this study was to evaluate the intraobserver and interobserver reproducibility of different measures of lower-calix anatomy. MATERIALS AND METHODS: We studied the intraobserver and interobserver reproducibility of parameters describing the lower-pole anatomy that are significant for treatment outcome. Forty renal units without urologic disease were analyzed by five independent urologists. Infundibular length (IL), infundibular width (IW), and lower infundibulopelvic angles (LIP) were measured by the Elbahnasy (LIP I), Keeley (LIP II), and Gupta (LIP III and LIP IV) methods. Statistical analysis of each parameter and investigator was performed. RESULTS: All LIP angles showed low interobserver correspondence: correlation coefficients (CC) did not exceed 0.44 (P < 0.05). Even the relatively clearly defined parameters IW and IL achieved CCs of only 0.63 and 0.49, respectively. The intraobserver correlation achieved better results: 0.73 (LIP I), 0.84 (LIP II), 0.73 (LIP III), 0.65 (LIP IV), 0.88 (IL), and 0.82 (IW). With the Elbahnasy method, almost all renal units were classified as favorable for stone persistence after shockwave lithotripsy. With the Keeley and Gupta methods, more than 50% of the kidneys were defined as having low clearance probability. CONCLUSIONS: Assessment of the chosen parameters is difficult and shows high interobserver variation. Inexperience in measuring the specific angles and low imaging quality can limit correct evaluation. The large number of kidneys with anatomy inappropriate for clearance of lower-pole stones may explain the poor outcome of shockwave treatment for stones in a lower calix. Prospective studies will determine the clinical value of anatomic assessments. 相似文献
35.
Hydrogen-1 MR spectroscopy of the peritumoral zone in patients with cerebral glioma: assessment of the value of the method 总被引:7,自引:0,他引:7
Walecki J Tarasów E Kubas B Czemicki Z Lewko J Podgórski J Sokól M Grieb P 《Academic radiology》2003,10(2):145-153
RATIONALE AND OBJECTIVES: The determination of tumor boundaries, especially in high-grade glioma, is critically important for the proper planning of treatment, but the standard diagnostic imaging methods do not enable precise delimitation of the extent of tumor cell infiltration into the surrounding tissue. The objective of this study was to assess the usefulness of hydrogen-1 (H-1) magnetic resonance (MR) spectroscopy for determining the extent of gliomatous infiltrate in the "uncertain zone'--the peritumoral area that appears unchanged on standard diagnostic MR images. MATERIALS AND METHODS: The study group consisted of 64 patients with cerebral glioma scheduled for tumor resection and subsequent radiation therapy. All patients were examined prior to resection with MR imaging and MR spectroscopy. MR spectra were obtained from examination of the solid part of the tumor and from two peritumoral volumes of interest located approximately along the axis of surgical access to the tumor. MR spectra obtained from a group of 32 healthy volunteers were used as control data. RESULTS: Analysis of the consequent voxels in the peritumoral zone revealed statistically significant differences in lipid/creatine and lactate/creatine metabolite ratios between patient subgroups with recurrent malignant lesions and without recurrent lesions. Significant differences also were found between the patient group and the control group in most metabolite ratios assessed. CONCLUSION: H-1 MR spectroscopic demonstration of metabolic changes in the peritumoral zone can guide treatment for cerebral glioma, enabling the physician to identify patients who have a high risk of recurrence. 相似文献
36.
37.
OBJECTIVE: To determine if sexually transmitted diseases (STDs), including human immunodeficiency virus (HIV) infection, risk assessment, and education tools provided as part of office-based primary care reduce adolescent risky sexual behaviors. DESIGN: A randomized intervention trial with 3- and 9-month follow-up. SETTING: Five staff-model managed care sites in Washington, DC (n = 19 pediatricians). PATIENTS: Consecutive 12- to 15-year-olds receiving a general health examination; 81% minority. Participation rate = 215/432 (50%). Nine-month follow-up rate = 197/215 (92%). INTERVENTION: Audiotaped STD risk assessment and education about staying safe (safer = condoms, safest = abstinence). MAIN OUTCOME MEASURES: Adolescent-reported sexual intercourse and condom use. RESULTS: More intervention adolescents reported pediatrician discussion on 11/13 sexual topics. Although more vaginal intercourse (odds ratio [OR] = 2.46, 95% confidence interval [CI] = 1.04-5.84) was reported in the intervention group at 3 months, this was not true of overall sexual intercourse (OR = 1.55, 95% CI =.73-3.32). More sexually active adolescents reported condom use in the intervention group at 3 months (OR = 18.05, 95% CI = 1.27-256.03). At 9 months, there were no group differences in sexual behaviors; however, more signs of STD were reported by the control (7/103) than the intervention group (0/94). CONCLUSIONS: STD risk assessment and education tools administered in a single office visit facilitated STD/HIV prevention education. Any impact on sexual activity and condom use was short-lived. Further research is needed to develop brief, office-based sexual risk reduction for young adolescents. 相似文献
38.
39.
Soliciting views of various communities on health research: a prelude to engagement in specific research projects 下载免费PDF全文
Howard L. Taras MD Michael W. Kalichman PhD Gery Schulteis PhD Jill Dumbauld MPH Yvonne Bell MBA Fe Fidelis Seligman MA Kathy D. West MBA 《Health expectations》2015,18(6):2753-2763
BackgroundMembers of the public are increasingly engaged in health‐service and biomedical research and provide input into the content of research, design and data sharing. As there is variation among different communities on how research is perceived, to engage all sectors of the general public research institutions need to customize their approach.ObjectiveThis paper explores how research institutions and community leaders can partner to determine the best ways to engage different sectors of the public in research.DesignFollowing a literature review, a research institution engaged with four different sectors of the public through their respective representative community‐based organizations (CBOs) by interviews with leaders, community member focus groups and a joint project.SettingSan Diego and Imperial Counties, California, United States of America (USA).ConclusionBefore embarking on more specific research projects, investigators can gain valuable insights about different communities'' attitudes to, and understanding of, health services and biomedical research by interacting directly with members of the community, collaborating with community leaders, and jointly identifying steps of engagement tailored to the community. 相似文献
40.
Smoking is a high-risk behavior that affects the health and economic welfare of society. Thus, it is important to quantify the economic burden smoking places on social institutions in the United States.
OBJECTIVE: The purpose of this review paper is to analyze smoking cost studies and to provide estimates that represent the economic costs of smoking from different perspectives of society, and as a whole.
METHODS: Current Contents (1996–), Health Star (1970–), and Medline (1966–) databases were searched through the use of pertinent subject headings and key words: tobacco use, smoking, cost, and economics. The internet was utilized to identify potential sources of epidemiological and cost information on smoking. Recent cost-of-illness studies using different methodologies: human capital, incidence, and prevalence were chosen for review based on their relevance.
RESULTS: Preliminary results indicate that the published cost studies available underestimate the "true" costs of smoking. The most current articles approximate annual direct medical costs to health care payers of $50 billion (1993); inflating to 1997 equals $59 billion or $1,200 per smoker. Although the latest cost studies do not attempt to estimate indirect costs, past studies have found indirect costs to be 1.5–2 times the direct costs. Therefore, using direct and indirect costs we estimate total smoking costs to be $150 billion (1993); inflating to 1997 equals $176 billion or $3,500 per smoker.
CONCLUSION: Quantifying the cost of smoking is a difficult task due to tobacco use infiltrating many aspects of life and the dependency of cost on perspective. Cost-of-illness studies provide cost estimation data which can be useful in aiding decision-makers who are allocating health care resources. 相似文献
OBJECTIVE: The purpose of this review paper is to analyze smoking cost studies and to provide estimates that represent the economic costs of smoking from different perspectives of society, and as a whole.
METHODS: Current Contents (1996–), Health Star (1970–), and Medline (1966–) databases were searched through the use of pertinent subject headings and key words: tobacco use, smoking, cost, and economics. The internet was utilized to identify potential sources of epidemiological and cost information on smoking. Recent cost-of-illness studies using different methodologies: human capital, incidence, and prevalence were chosen for review based on their relevance.
RESULTS: Preliminary results indicate that the published cost studies available underestimate the "true" costs of smoking. The most current articles approximate annual direct medical costs to health care payers of $50 billion (1993); inflating to 1997 equals $59 billion or $1,200 per smoker. Although the latest cost studies do not attempt to estimate indirect costs, past studies have found indirect costs to be 1.5–2 times the direct costs. Therefore, using direct and indirect costs we estimate total smoking costs to be $150 billion (1993); inflating to 1997 equals $176 billion or $3,500 per smoker.
CONCLUSION: Quantifying the cost of smoking is a difficult task due to tobacco use infiltrating many aspects of life and the dependency of cost on perspective. Cost-of-illness studies provide cost estimation data which can be useful in aiding decision-makers who are allocating health care resources. 相似文献