全文获取类型
收费全文 | 3573篇 |
免费 | 404篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 100篇 |
妇产科学 | 103篇 |
基础医学 | 460篇 |
口腔科学 | 42篇 |
临床医学 | 622篇 |
内科学 | 717篇 |
皮肤病学 | 57篇 |
神经病学 | 268篇 |
特种医学 | 40篇 |
外科学 | 363篇 |
综合类 | 68篇 |
预防医学 | 493篇 |
眼科学 | 36篇 |
药学 | 266篇 |
中国医学 | 1篇 |
肿瘤学 | 344篇 |
出版年
2023年 | 23篇 |
2022年 | 17篇 |
2021年 | 52篇 |
2020年 | 23篇 |
2019年 | 58篇 |
2018年 | 73篇 |
2017年 | 71篇 |
2016年 | 74篇 |
2015年 | 86篇 |
2014年 | 112篇 |
2013年 | 159篇 |
2012年 | 225篇 |
2011年 | 240篇 |
2010年 | 142篇 |
2009年 | 132篇 |
2008年 | 227篇 |
2007年 | 234篇 |
2006年 | 226篇 |
2005年 | 242篇 |
2004年 | 247篇 |
2003年 | 225篇 |
2002年 | 213篇 |
2001年 | 74篇 |
2000年 | 71篇 |
1999年 | 59篇 |
1998年 | 42篇 |
1997年 | 46篇 |
1996年 | 33篇 |
1995年 | 37篇 |
1994年 | 16篇 |
1993年 | 22篇 |
1992年 | 31篇 |
1991年 | 33篇 |
1990年 | 32篇 |
1989年 | 32篇 |
1988年 | 28篇 |
1987年 | 17篇 |
1986年 | 29篇 |
1985年 | 24篇 |
1984年 | 20篇 |
1983年 | 25篇 |
1982年 | 23篇 |
1981年 | 12篇 |
1980年 | 16篇 |
1979年 | 14篇 |
1978年 | 18篇 |
1976年 | 10篇 |
1975年 | 15篇 |
1974年 | 14篇 |
1973年 | 10篇 |
排序方式: 共有3986条查询结果,搜索用时 31 毫秒
71.
Judy S. Smith Gwen Irwin Mary Viney Lynda Watkins Shonnie Pinno Morris Kenn M. Kirksey Adama Brown 《Journal of the Association for Vascular Access》2012,17(3):137-143
BackgroundElimination of catheter-related bloodstream infections is a major focus in health care. According to the Centers for Disease Control and Prevention and the Infusion Nurses Society, the optimal time for needleless connector disinfection has not yet been empirically established.MethodsUsing experimental design and established lab procedure, a 0.5 MacFarland suspension was used to inoculate 172 needleless connectors with bacteria (Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa) and allowed to dry for 18 hours. Five groups of connectors (n = 27 per group) were disinfected using 70% isopropyl alcohol with friction for 5, 8, 10, 12, and 15 seconds, and flushed with 0.5 mL nonbacteriostatic sterile normal saline onto sheep-blood agar plates for incubation at 35°C for 48 hours. Bacterial growth (1 colony) was noted on 2 negative controls; therefore, a second sample (n = 172) was tested as above using additional precautions of masking, gloving, and gowning. A third group of connectors was tested using a 0.5 MacFarland suspension containing yeast (Candida albicans).ResultsGroup 1 showed significant (χ24 = 37.93; P = .00) and strong (Cramér's V = 0.53; P = .00) associations between scrub time and growth status. Although not statistically significant, Groups 2 and 3 demonstrated clinically significant associations between these factors.ConclusionsAlthough additional research is warranted, our study showed that disinfection times of 5 and 8 seconds were inadequate for reducing bacterial transfer. However, disinfection times of 10, 12, and 15 seconds resulted in comparable, decreased rates of bacterial migration. 相似文献
72.
High pesticide exposure events and DNA methylation among pesticide applicators in the agricultural health study 下载免费PDF全文
73.
74.
75.
Melloni C Alexander KP Milford-Beland S Newby LK Szczech LA Pollack CV Kirk JD Christenson RH Harrington RA Gibler WB Ohman EM Peterson ED Roe MT;Crusade Investigators 《Clinical cardiology》2008,31(3):125-129
BACKGROUND: The prognostic value of cardiac troponins (cTn) in patients with non-ST-segment elevation acute coronary syndromes (NSTE ACS) and chronic kidney disease (CKD) is debated. HYPOTHESIS: We tested the performance of cTnI and cTnT for risk stratification in patients with CKD and evaluated the prognostic significance of cTnI and cTnT elevations by their magnitude across the range of CKD severity. METHODS: We examined correlations among cTn elevation, CKD, and in-hospital mortality in 31,586 high-risk patients with NSTE ACS included in the Can Rapid Risk Stratification of Unstable Angina Patients Suppress ADverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association Guidelines initiative (CRUSADE). Cardiac tropinins I and T levels were categorized as ratios of each site's upper limit of normal (ULN) for myocardial necrosis: normal (cTn ratio < or =1 x ULN), mild (cTn ratio > 1-3 x ULN), and major (cTn ratio > 3 x ULN) elevation. Estimated glomerular filtration rate (eGFR) was calculated using the abbreviated Modification of Diet in Renal Disease equation. Stages of CKD were categorized as normal to mild (eGFR > 60 mL/min), moderate (eGFR 30-60 mL/min), or severe (eGFR < 30 mL/min). RESULTS: Mortality increased more steeply across CKD stages (2.0%-12.9%) than across cTn ratio categories (2.7%-5.4%). In normal or mild CKD, mortality was low regardless of cTn elevations. In moderate CKD, mortality increased incrementally with cTnI (3.3% versus 5.4% versus 7.4%) and cTnT (3.7% versus 5.3% versus 7.3%) elevation. Among severe CKD patients, only major cTn elevations further distinguished risk (cTnI: 10.1% versus 9.7% versus 14.6%; cTnT: 7.0% versus 5.7% versus 14.0%). CONCLUSIONS: In patients with CKD, cTnI and cTnT perform equally in differentiating short-term prognosis following NSTE ACS; however, the prognostic impact of cTn is dependent upon the degree of CKD severity. 相似文献
76.
Almost every woman and some men will encounter hot flushes during their lifetime. Despite the prevalence of the symptoms, the pathophysiology of hot flushes remains unknown. A decline in hormone concentrations might lead to alterations in brain neurotransmitters and to instability in the hypothalamic thermoregulatory setpoint. The most effective treatments for hot flushes include oestrogens and progestagens. However, many women and their physicians are reluctant to accept hormonal treatments. Women want non-pharmacological treatments but unfortunately such treatments are not very effective, and non-hormonal drugs are often associated with adverse effects. Results from recent studies showed that selective serotonin reuptake inhibitors and other similar compounds can safely reduce hot flushes. Moreover, the efficacy of these drugs provides new insight into the pathophysiology of hot flushes. In this critical review, we assess knowledge of the epidemiology, pathophysiology, and treatment of hot flushes. 相似文献
77.
Stöllberger C Finsterer J Zlabinger GJ Weihsengruber F Redtenbacher S Bonner G Herkner K Deutsch M 《The Journal of heart valve disease》2003,12(4):530-534
Antiproteinase 3 antibodies (antiPR3) are assumed to be subtypes of antineutrophil cytoplasmic autoantibodies (ANCA), with a high specificity for active Wegener's granulomatosis and microscopic polyangiitis. Thus, antiPR3 positivity in ELISA, together with negativity in indirect immunofluorescence (IIF) is a rare finding. A 56-year-old man with Dupuytren's contracture and polyneuropathy was admitted for leukocytoclastic vasculitis. Echocardiography, performed because of fever and dyspnea, detected aortic valve endocarditis. Because of severe aortic insufficiency the valve was replaced. Blood cultures and bacteriologic investigations of the explanted valve were negative. AntiPR3 were elevated (123-163 U/ml; normal <6 U/ml), together with negativity in IIF. This case shows that antiPR3 elevation with negative ANCA may be associated with vasculitis, endocarditis, polyneuropathy and Dupuytren's contracture. A causal relationship between the clinical presentation and antiPR3 elevation is likely. In order not to miss such cases of vasculitis, combined screening by IIF and ELISA is recommended in selected cases. 相似文献
78.
M B Leon Y Almagor A L Bartorelli L G Prevosti P S Teirstein R Chang D L Miller P D Smith R F Bonner 《Circulation》1990,81(1):143-155
In 12 patients (aged 64 +/- 10 years) with femoropopliteal occlusions (1-27 cm; average, 8.4 cm length) that could not be recanalized by standard guidewire-balloon angioplasty techniques, percutaneous laser-assisted balloon angioplasty was performed by use of a new fluorescence-guided dual-laser system. Plaque detection by 325-nm laser-excited fluorescence spectroscopy provided real-time feedback control to a 480-nm pulsed dye laser (2-microseconds pulses) for atheroma ablation. By means of a common 200-microns optical fiber, after diagnostic fluorescence sensing, computer algorithms directed a fire or no-fire signal (5 Hz) to the treatment laser for selective plaque removal. Laser recanalization (15-50 mJ/pulse) was successful in 10 of 12 patients; this procedure was followed by definitive balloon angioplasty in seven of 12 patients with increased ankle/arm indexes (from 0.60 +/- 0.12 at baseline to 0.84 +/- 0.11 after treatment, p = 0.0043). In laser and balloon angioplasty failures, all femoropopliteal occlusions were heavily calcified, and there were two mechanical guidewire perforations without clinical sequelae. Ablation of calcified lesions required higher pulse energies and greater total energy per centimeter of recanalized tissue (1,837 +/- 1,251 mJ/cm vs. 90 +/- 39 mJ/cm, p = 0.0036). Fluorescence spectroscopy (n = 219 sites) was helpful in flush occlusions and correctly identified plaque, underlying media, and thrombus by changes in fluorescence intensity, shape, and peak position. Thus, when fluorescence-guided laser angioplasty was used in a subgroup of patients refractory to standard angioplasty techniques, primary recanalization and subsequent balloon angioplasty of femoropopliteal occlusions was successful in 83% and 58% of the patients, respectively. Importantly, treatment of heavily calcified lesions accounted for all of the failures and will require modified delivery systems to create larger primary channels and to increase catheter-tip control, which should improve clinical results in the future. 相似文献
79.
OBJECTIVES: To estimate the frequency of HIV/sexually transmitted disease (STD) counseling among patients tested for HIV or STD infection at physician offices and hospital outpatient departments and to describe the factors associated with HIV/STD counseling in private settings in the USA. DESIGN: Cross-sectional study of patients served by physicians in private settings in the USA. METHODS: We analyzed 1997-1998 data from two representative national surveys of ambulatory care visits in private settings by persons aged 18-64 years. RESULTS: During 1997-1998, 12.7 million ambulatory care visits included HIV or STD testing. HIV/STD counseling was documented in 35% of all visits and in 28% of visits by pregnant women at the time HIV or STD tests were done. Counseling was less common when only HIV tests (21%) or STD tests (37%) alone were carried out than when both HIV and STD tests (50%) were performed. Counseling was more common (65%) if the patient's reason for visit was related to HIV, STD, or genitourinary complaints than if the visit was for other reasons. CONCLUSIONS: Private physicians often counseled about HIV/STD when testing patients with symptoms. The proportion of other visits in which counseling accompanied HIV or STD tests was variable. This suggests the need for a better understanding of the reasons why clinicians in private settings decide whether to counsel patients about HIV and STD when they order testing, barriers to offering counseling, and interventions to increase counseling when appropriate. 相似文献
80.
Clint Douglas Diana Schmalkuche Debra Nizette Patsy Yates Ann Bonner 《Collegian (Royal College of Nursing, Australia)》2018,25(4):363-370