全文获取类型
收费全文 | 1116篇 |
免费 | 44篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 15篇 |
妇产科学 | 19篇 |
基础医学 | 107篇 |
口腔科学 | 16篇 |
临床医学 | 72篇 |
内科学 | 301篇 |
皮肤病学 | 33篇 |
神经病学 | 50篇 |
特种医学 | 19篇 |
外科学 | 142篇 |
综合类 | 131篇 |
一般理论 | 1篇 |
预防医学 | 143篇 |
眼科学 | 12篇 |
药学 | 56篇 |
肿瘤学 | 37篇 |
出版年
2023年 | 5篇 |
2021年 | 15篇 |
2020年 | 5篇 |
2019年 | 13篇 |
2018年 | 26篇 |
2017年 | 22篇 |
2016年 | 17篇 |
2015年 | 19篇 |
2014年 | 34篇 |
2013年 | 52篇 |
2012年 | 57篇 |
2011年 | 64篇 |
2010年 | 43篇 |
2009年 | 34篇 |
2008年 | 62篇 |
2007年 | 66篇 |
2006年 | 57篇 |
2005年 | 59篇 |
2004年 | 36篇 |
2003年 | 48篇 |
2002年 | 33篇 |
2001年 | 25篇 |
2000年 | 23篇 |
1999年 | 29篇 |
1998年 | 5篇 |
1997年 | 11篇 |
1996年 | 10篇 |
1995年 | 8篇 |
1992年 | 24篇 |
1991年 | 17篇 |
1990年 | 20篇 |
1989年 | 17篇 |
1988年 | 15篇 |
1987年 | 10篇 |
1986年 | 17篇 |
1985年 | 19篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 11篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1973年 | 6篇 |
1972年 | 4篇 |
1971年 | 13篇 |
1970年 | 5篇 |
1966年 | 4篇 |
1965年 | 5篇 |
1918年 | 5篇 |
排序方式: 共有1162条查询结果,搜索用时 15 毫秒
31.
Joseph A. Volpe M.D. Maj. M.C. Robert J. Lull M.D. Maj. M.C. Martin L. Nusynowitz M.D. Lt. Col. M.C. 《Journal of surgical oncology》1971,3(6):649-655
Liver scans, biopsies, and function studies were reviewed in 63 cancer patients and correlated with autopsy material to determine the value of the liver scan in such patients. The scan is abnormal in 96% of patients with autopsy-confirmed hepatic disease, but the scan pattern is of little assistance in differentiating tumor from nontumor pathology. Liver function studies are equally nonspecific and even less sensitive than the scan. Percutaneous biopsy, while diagnostic when positive, is insensitive, showing false-negative results in up to 40% of cases. The liver scan, as the most sensitive indicator of liver disease, may be most valuable when normal, reflecting a better prognosis and aiding in the determination of treatment. When the liver scan is abnormal, more specific tests must be employed. A method of approach is suggested. 相似文献
32.
Pérez CM Suárez E Torres EA Román K Colón V 《International journal of epidemiology》2005,34(3):593-599
BACKGROUND: Limited information about the epidemiology of hepatitis C virus (HCV) infection is available in Puerto Rico, one of the areas hardest hit by the human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) epidemic. We estimated the prevalence of HCV infection and identified correlates of seropositivity in the municipality of San Juan, Puerto Rico. METHODS: A probability cluster design was employed to select a sample of households representative of the population aged 21-64 years in San Juan during 2001-2002. All 964 subjects completed a face-to-face interview to gather data on demographics and self-reported risk behaviours followed by venipuncture for HCV antibody testing. Variables that were at least marginally associated with HCV seroprevalence (P < 0.10) in the bivariate analyses were considered for inclusion into the multiple logistic regression model to estimate the adjusted prevalence odds ratio (POR). RESULTS: Overall weighted prevalence of HCV infection was 6.3% (95% CI 3.6-10.9%). A significant (P < 0.05) higher prevalence was observed among subjects with the following characteristics: age 30-49 (9.5%), male sex (10.6%), < or =12 years of education (9.6%), no health coverage (12.6%), lifetime heroin use (39.2%), lifetime cocaine use (39.6%), tattooing practices (34.2%), history of imprisonment (32.8%), and self-reported histories of hepatitis B virus infection (30.4%) and HIV/AIDS (92.1%). Multivariate logistic regression revealed that tattooing practices (POR = 8.9; 95% CI 1.7-44.7), lifetime cocaine use (POR = 5.5; 95% CI 2.2-13.5), blood transfusions prior to 1992 (POR = 4.0; 95% CI 1.6-10.1), lifetime heroin use (POR = 3.3; 95% CI 1.4-7.8), and history of imprisonment (POR = 2.3; 95% CI 1.1-4.9) remained significantly associated with HCV seropositivity. CONCLUSIONS: The large prevalence of HCV infection observed in Puerto Rican adults residing in San Juan suggest that HCV infection is an emerging public health concern and merits further investigation. 相似文献
33.
34.
Helical computed tomographic angiography for the diagnosis of traumatic arterial injuries of the extremities 总被引:6,自引:0,他引:6
BACKGROUND: The radiologic study of choice for evaluation of traumatic arterial injuries is conventional arteriography, but it poses the risks of an invasive procedure. Computed tomographic arteriography (CTA) is emerging as a new way to study arterial anatomy, with the additional advantages of being noninvasive and a technique that allows evaluation of different body areas simultaneously. Our experience using CTA for evaluation of traumatic arterial injuries is provided in this study. METHODS: A retrospective review over a 22-month period of all adult patients undergoing CTA for evaluation of traumatic injuries to the extremities was performed. RESULTS: A total of 97 CTA studies were performed in the 95 patients. CTA adequately demonstrated the nature and location of all the arterial injuries when compared with conventional arteriography or surgical exploration. Abnormal CTA results included 21 arterial occlusions, 2 intimal flap defects, and 2 pseudoaneurysms. Nine of these 25 injuries were confirmed by surgery only, 10 by surgery and arteriography, and 6 by arteriography only. Normal CTA results were confirmed with arteriography in 10 cases. No missed injuries were encountered in patients with normal CTA results. CONCLUSION: CTA is a reliable technique for the detection and characterization of traumatic extremity arterial injuries. These results suggest CTA may be an alternative to conventional arteriography for the diagnosis of traumatic arterial injuries. 相似文献
35.
Subclinical thyroid disease: scientific review and guidelines for diagnosis and management 总被引:64,自引:2,他引:62
Surks MI Ortiz E Daniels GH Sawin CT Col NF Cobin RH Franklyn JA Hershman JM Burman KD Denke MA Gorman C Cooper RS Weissman NJ 《JAMA》2004,291(2):228-238
Context Patients with serum thyroid-stimulating hormone (TSH) levels outside the reference range and levels of free thyroxine (FT4) and triiodothyronine (T3) within the reference range are common in clinical practice. The necessity for further evaluation, possible treatment, and the urgency of treatment have not been clearly established. Objectives To define subclinical thyroid disease, review its epidemiology, recommend an appropriate evaluation, explore the risks and benefits of treatment and consequences of nontreatment, and determine whether population-based screening is warranted. Data Sources MEDLINE, EMBASE, Biosis, the Agency for Healthcare Research and Quality, National Guideline Clearing House, the Cochrane Database of Systematic Reviews and Controlled Trials Register, and several National Health Services (UK) databases were searched for articles on subclinical thyroid disease published between 1995 and 2002. Articles published before 1995 were recommended by expert consultants. Study Selection and Data Extraction A total of 195 English-language or translated papers were reviewed. Editorials, individual case studies, studies enrolling fewer than 10 patients, and nonsystematic reviews were excluded. Information related to authorship, year of publication, number of subjects, study design, and results were extracted and formed the basis for an evidence report, consisting of tables and summaries of each subject area. Data Synthesis The strength of the evidence that untreated subclinical thyroid disease is associated with clinical symptoms and adverse clinical outcomes was assessed and recommendations for clinical practice developed. Data relating the progression of subclinical to overt hypothyroidism were rated as good, but data relating treatment to prevention of progression were inadequate to determine a treatment benefit. Data relating a serum TSH level higher than 10 mIU/L to elevations in serum cholesterol were rated as fair but data relating to benefits of treatment were rated as insufficient. All other associations of symptoms and benefit of treatment were rated as insufficient or absent. Data relating a serum TSH concentration lower than 0.1 mIU/L to the presence of atrial fibrillation and progression to overt hyperthyroidism were rated as good, but no data supported treatment to prevent these outcomes. Data relating restoration of the TSH level to within the reference range with improvements in bone mineral density were rated as fair. Data addressing all other associations of subclinical hyperthyroid disease and adverse clinical outcomes or treatment benefits were rated as insufficient or absent. Subclinical hypothyroid disease in pregnancy is a special case and aggressive case finding and treatment in pregnant women can be justified. Conclusions Data supporting associations of subclinical thyroid disease with symptoms or adverse clinical outcomes or benefits of treatment are few. The consequences of subclinical thyroid disease (serum TSH 0.1-0.45 mIU/L or 4.5-10.0 mIU/L) are minimal and we recommend against routine treatment of patients with TSH levels in these ranges. There is insufficient evidence to support population-based screening. Aggressive case finding is appropriate in pregnant women, women older than 60 years, and others at high risk for thyroid dysfunction. 相似文献
36.
Colón-Emeric CS Caminis J Suh TT Pieper CF Janning C Magaziner J Adachi J Rosario-Jansen T Mesenbrink P Horowitz ZD Lyles KW;HORIZON Recurrent Fracture Trial 《Current medical research and opinion》2004,20(6):903-910
OBJECTIVE: To present the novel design of a trial testing the safety and efficacy of a yearly bisphosponate, zoledronic acid, in preventing new clinical fractures in patients with recent low trauma hip fracture repair. Research design and methods: Randomized, placebo-controlled, triple-blind study. One hundred and fifteen clinical centers worldwide are recruiting approximately 1714 subjects aged 50 years and over (no upper age limit, median age of enrolled subjects to date 79 years) who have undergone surgical repair of a low trauma hip fracture in the preceding 90 days. Patients will be assigned at random to an intervention group (5 mg zoledronic acid intravenously yearly) or a control group (placebo infusion yearly). Both groups receive a loading dose of Vitamin D2 or D3 IM or orally, followed by 800-1200 IU Vitamin D and 1000-1500 mg elemental calcium orally on a daily basis. Concomitant therapy with calcitonin, hormone replacement therapy, selective estrogen receptor modulators, tibolone, and external hip protectors are allowed. MAIN OUTCOME MEASURES: The primary endpoint is subsequent skeletal fractures as adjudicated by a clinical endpoints committee blinded to intervention status. Secondary outcomes include delayed hip fracture healing, changes in bone mineral density, and health resource utilization. Subjects will be recruited over a 3-4 year period and will be followed until 211 primary endpoints are accrued and adjudicated. CONCLUSIONS: This randomized clinical trial is novel among osteoporosis therapies as it (1). targets hip fracture patients, a previously understudied group, and (2). uses only clinically evident fractures as the primary outcome. Ethical and practical considerations in studying this frail population are discussed. 相似文献
37.
This study examined the impact of changes in self-efficacy over time on HIV-related injection and sex risk behaviors among Puerto Rican drug injectors and crack smokers. Baseline (T1) and 6-month follow-up (T2) data were collected between 1998 and 2000 in New York and Puerto Rico (follow-up rate=79%, 952/1199). Differences in scores on self-efficacy (for risk behaviors) between T1 and T2 were first computed and dichotomized (negative change vs. no/positive change). Those with negative change in self-efficacy were more likely than those with no/positive change to engage in HIV injection and sex risk behaviors at T2. The relationships were significant in multiple logistic regressions after controlling for the effects of potential confounding variables. The findings indicate that improving perceived self-efficacy for risk reduction can help reduce HIV transmission behaviors in high-risk drug users. HIV/AIDS prevention programs should include a focus on enhancing self-efficacy for reducing risk behaviors. 相似文献
38.
Vázquez GJ Robledo IE Arroyo A Nadal E Rodríguez R Bermúdez M Colón M 《Puerto Rico health sciences journal》2003,22(3):265-271
Few studies have been performed in Puerto Rico concerning the antimicrobial resistance pattern of clinically significant Gram-negative bacilli. The antimicrobial resistance patterns of 5,590 Gram-negative bacteria obtained from three Community-Private Hospitals (CPH) and three University-Affiliated Hospitals (UAH) were evaluated utilizing the institutions' antimicrobial susceptibility reports for the year 2000. The objectives of this study were: to retrospectively evaluate the reported in vitro resistance of clinical isolates of E. coli, K. pneumoniae, E. cloacae, S. marcescens, P. aeruginosa and A. baumannii to selected standard antibiotics and to compare the antimicrobial resistance patterns between Community-Private (CPH) and University Affiliated hospitals (UAH). E. coli was the most common Gram-negative enteric bacilli in both CPH and UAH. In UAH, E. coli demonstrated a statistically significant higher resistance to the selected beta lactams and amikacin antibiotics but not to ciprofloxacin or gentamicin. For K. pneumoniae, the antimicrobial resistant pattern showed that UAH isolates were significantly more resistant to the tested antibiotics with the exception of ceftriaxone. In CPH, E. cloacae isolates were significantly more resistant to piperacillin-tazobactam, ciprofloxacin and gentamicin, while in UAH this organism was more resistant to amikacin. In UAH, S. marcescens isolates demonstrated a statistically significant higher resistance to all tested antibiotics with the exception of imipenem, which was similar in both hospitals group. Pseudomonas aeruginosa demonstrated a statistically significant higher resistance in UAH to all selected antibiotics with the exception of ciprofloxacin and gentamicin, which was similar in both hospitals group. Acinetobacter baumannii was the most resistant organisms in both hospitals group. UAH isolates were significantly more resistant than CPH isolates for all tested antibiotics. When compare with other large-scale antimicrobial resistance studies, the present study results suggest an apparent higher resistance in the Puerto Rican isolates. The high numbers of antimicrobial resistant Gram-negative bacilli in our study strongly suggest multiple mechanisms of antimicrobial resistance including the presence of extended spectrum and chromosomally derepressed beta-lactamases. 相似文献
39.
Vázquez GJ Robledo IE Arroyo A Nadal E Rodríguez R Bermudez M Colón M 《Puerto Rico health sciences journal》2003,22(2):131-136
The antimicrobial resistance patterns of 2,462 selected Gram-positive cocci obtained from three Community-Private Hospitals (CPH) and three University-Affiliated Hospitals (UAH) were evaluated utilizing the institutions' antimicrobial susceptibility reports for the year 2000. The objectives of this study were: 1) to evaluate the in vitro resistance to selected standard antibiotics of Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium and Streptococcus pneumoniae clinical isolates, and 2) to compare the antimicrobial resistance patterns between community-private (CPH) and university-affiliated hospitals (UAH). Staphylococcus aureus was the most common Gram-positive isolated organism in CPH (63.3%) followed by E. faecalis (31.0%). In UAH, the most prevalent cocci were E. faecalis (51.7%) followed by S. aureus (43.9%). Enterococcus faecium represented 2.3% and 4.4% of CPH and UAH isolates, respectively. Streptococcus pneumoniae represented 3.4% of the total Gram-positive isolates from CPH, no S. pneumoniae was reported in UAH. The antimicrobial susceptibility results showed that for Staphylococcus aureus there was a statistically significant higher resistance to methicillin and thrimethoprim sulfamethoxazole in UAH, while resistance to erythromycin was significantly higher in CPH. There was no difference in the resistance of S. aureus to other antimicrobial agents between hospitals groups. A statistically significant resistant to vancomycin was found between enterococcal isolates from UAH (43%) and CPH (12.7%). High-level aminoglycoside resistance (HLAR) was observed among UAH enterococcal isolates with E. faecium showing a higher resistance than E. faecalis, no data for HLAR in CPH could be obtained. For pneumococci 46% of CPH isolates were resistant to penicillin. In summary, there are important differences in the prevalence and antimicrobial resistance between the Gram-positive bacteria isolated from community and teaching hospitals. 相似文献
40.
Robles RR Matos TD Colón HM Sahai H Reyes JC Marrero CA Calderón JM 《Puerto Rico health sciences journal》2003,22(4):369-376
This paper assesses mortality rate for a cohort of drug users in Puerto Rico compared with that of the Island's general population, examining causes of death and estimating relative risk of death. Date and cause of death were obtained from death certificates during 1998. Vital status was confirmed through contact with subjects, family, and friends. HIV/AIDS was the major cause of death (47.7%), followed by homicide (14.6%), and accidental poisoning (6.3%). Females had higher relative risk of death than males in all age categories. Not living with a sex partner and not receiving drug treatment were related to higher mortality due to HIV/AIDS. Drug injection was the only variable explaining relative risk of death due to overdose. Puerto Rico needs to continue developing programs to prevent HIV/AIDS among drug users. Special attention should be given to young women, who appear to be in greatest need of programs to prevent early mortality. 相似文献