全文获取类型
收费全文 | 5102篇 |
免费 | 314篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 288篇 |
妇产科学 | 84篇 |
基础医学 | 647篇 |
口腔科学 | 132篇 |
临床医学 | 381篇 |
内科学 | 992篇 |
皮肤病学 | 87篇 |
神经病学 | 342篇 |
特种医学 | 224篇 |
外科学 | 575篇 |
综合类 | 89篇 |
一般理论 | 3篇 |
预防医学 | 304篇 |
眼科学 | 474篇 |
药学 | 403篇 |
1篇 | |
中国医学 | 21篇 |
肿瘤学 | 333篇 |
出版年
2023年 | 48篇 |
2022年 | 89篇 |
2021年 | 232篇 |
2020年 | 128篇 |
2019年 | 144篇 |
2018年 | 164篇 |
2017年 | 121篇 |
2016年 | 140篇 |
2015年 | 156篇 |
2014年 | 221篇 |
2013年 | 250篇 |
2012年 | 409篇 |
2011年 | 382篇 |
2010年 | 216篇 |
2009年 | 180篇 |
2008年 | 285篇 |
2007年 | 295篇 |
2006年 | 273篇 |
2005年 | 244篇 |
2004年 | 220篇 |
2003年 | 145篇 |
2002年 | 130篇 |
2001年 | 102篇 |
2000年 | 90篇 |
1999年 | 83篇 |
1998年 | 28篇 |
1997年 | 23篇 |
1996年 | 17篇 |
1995年 | 23篇 |
1994年 | 14篇 |
1993年 | 16篇 |
1992年 | 34篇 |
1991年 | 38篇 |
1990年 | 43篇 |
1989年 | 45篇 |
1988年 | 28篇 |
1987年 | 33篇 |
1986年 | 32篇 |
1985年 | 27篇 |
1984年 | 21篇 |
1983年 | 19篇 |
1982年 | 14篇 |
1981年 | 22篇 |
1980年 | 13篇 |
1979年 | 32篇 |
1977年 | 16篇 |
1975年 | 17篇 |
1973年 | 13篇 |
1972年 | 13篇 |
1970年 | 13篇 |
排序方式: 共有5428条查询结果,搜索用时 31 毫秒
1.
2.
Fayiqa Ahamed Bahkir Srinivasan Subramanian Grandee 《Indian journal of ophthalmology》2020,68(11):2378
Purpose:Since the declaration of the lockdown due to COVID-19, the usage of digital devices has gone up across the globe, resulting in a challenge for the visual systems of all ages. The purpose of this study is to assess the impact of the lockdown on digital device usage, and consequently, the ocular surface health implications and circadian rhythm abnormalities related to digital eye strain.Methods:An open online survey was sent through various social media platforms and was open for a period of 2 weeks.Results:A total of 407 usable responses were obtained; the average age of respondents was 27.4 years. Typically, 93.6% of respondents reported an increase in their screen time since the lockdown was declared. The average increase in digital device usage was calculated at about 4.8 ± 2.8 h per day. The total usage per day was found to be 8.65 ± 3.74 hours. Sleep disturbances have been reported by 62.4% of people. Typically, 95.8% of respondents had experienced at least one symptom related to digital device usage, and 56.5% said that the frequency and intensity of these symptoms increased since the lockdown was declared.Conclusion:The study highlighted the drastic increase in use of digital devices after the initiation of the COVID-19 lockdown, and along with it, the slow deterioration of ocular health across all age groups. Awareness about prevention of digital eye strain should be stressed, and going forward, measures to bring these adverse effects to a minimum should be explored. 相似文献
3.
Alexander Real Chierika Ukogu Divya Krishnamoorthy Nicole Zubizarreta Samuel K. Cho Andrew C. Hecht James C. Iatridis 《The spine journal》2019,19(2):225-231
Background Context
Low back pain (LBP) is a common complaint in clinical practice of multifactorial origin. Although obesity has been thought to contribute to LBP primarily by altering the distribution of mechanical loads on the spine, the additional contribution of obesity-related conditions such as diabetes mellitus (DM) to LBP has not been thoroughly examined.Purpose
To determine if there is a relationship between DM and LBP that is independent of body mass index (BMI) in a large cohort of adult survey participants.Study Design
Retrospective analysis of prospectively collected National Health and Nutrition Examination Survey (NHANES) data to characterize associations between LBP, DM, and BMI in adults subdivided into 6 subpopulations: normal weight (BMI 18.5–25), overweight (BMI 25–30), and obese (BMI >30) diabetics and nondiabetics. Diabetes was defined with glycohemoglobin A1c (HbA1c) ≥6.5%.Patient Sample
11,756 participants from NHANES cohort.Outcome Measures
Percentage of LBP reported.Methods
LBP reported in the 1999-2004 miscellaneous pain NHANES questionnaire was the dependent variable examined. Covariates included HbA1c, BMI, age, and family income ratio to poverty as continuous variables as well as race, gender, and smoking as binary variables. Individuals were further subdivided by weight class and diabetes status. Regression and graphical analyses were performed on the study population as a whole and also on subpopulations.Results
Increasing HbA1c did not increase the odds of reporting LBP in the full cohort. However, multivariate logistic regression of the 6 subpopulations revealed that the odds of LBP significantly increased with increasing HbA1c levels in normal weight diabetics. No other subpopulations reported significant relationships between LBP and HbA1c. LBP was also significantly associated with BMI for normal weight diabetics and also for obese subjects regardless of their DM status.Conclusions
LBP is significantly related to DM status, but this relationship is complex and may interact with BMI. These results support the concept that LBP may be improved in normal weight diabetic subjects with improved glycemic control and weight loss, and that all obese LBP subjects may benefit from improved weight loss alone. 相似文献4.
5.
BackgroundExcessive consumption of ethanol is known to activate the mTORC1 pathway and to enhance the Collapsin Response Mediator Protein-2 (CRMP-2) levels in the limbic region of brain. The latter helps in forming microtubule assembly that is linked to drug taking or addiction-like behavior in rodents. Therefore, in this study, we investigated the effect of lacosamide, an antiepileptic drug and a known CRMP-2 inhibitor, which binds to CRMP-2 and inhibits the formation of microtubule assembly, on ethanol-induced conditioned place preference (CPP) in mice.MethodsThe behavior of mice following ethanol addiction and withdrawal was assessed by performing different behavioral paradigms. Mice underwent ethanol-induced CPP training with alternate dose of ethanol (2 g/kg, po) and saline (10 ml/kg, po). The effect of lacosamide on the expression of ethanol-induced CPP and on ethanol withdrawal associated anxiety and depression-like behavior was evaluated. The effect of drug on locomotor activity was also assessed and hippocampal CRMP-2 levels were measured.ResultsEthanol-induced CPP was associated with enhanced CRMP-2 levels in the hippocampus. Lacosamide significantly reduced the expression of ethanol-induced CPP and alleviated the levels of hippocampal CRMP-2 but aggravated withdrawal-associated anxiety and depression in mice.ConclusionThe present study demonstrated the beneficial effect of lacosamide in attenuation of expression of ethanol induced conditioned place preference via reduction of hippocampal CRMP-2 level. These findings suggest that lacosamide may be investigated further for ethanol addiction but not for managing withdrawal. 相似文献
6.
V Aerra M Kuduvalli AN Moloto AK Srinivasan AD Grayson BM Fabri AY Oo 《Journal of cardiothoracic surgery》2006,1(1):6-5
Background
Atrial fibrillation can occur in up to 40% of patients undergoing coronary surgery. 相似文献7.
8.
The goals of this report are: 1) to review the number needed to treat (NNT) concept, which, although well established in many sectors of medicine, is still relatively new to the radiotherapy community; 2) to discuss several clinical radiotherapy examples illustrating the inherent advantages of the NNT approach; and 3) to discuss potential future roles of the NNT concept within radiotherapy. 相似文献
9.
D K Srinivasa A Sahai S B Rotti M B Soudarssanane M Danabalan R N Sahoo K A Narayan G Ramalingam S Srinivasan S Mahadevan B V Bhat P Nalini 《Journal of epidemiology and community health》1997,51(4):443-448
STUDY OBJECTIVES: To assess the poliomyelitis trend, including study of the epidemiological features, and to correlate this with the immunisation coverage of infants. DESIGN: Three annual lameness surveys in children aged 0-60 months employing cluster sampling methods and a series of five cross sectional surveys of immunisation coverage in children aged 12-23 months of age were undertaken. SETTING: Pondicherry, India, 1988-92. SUBJECTS: More than 10,000 children in the age group of 0-60 months took part in the three annual lameness surveys and samples of 210 children aged 12-23 months were covered each year in immunisation coverage surveys. MEASUREMENTS AND MAIN RESULTS: Altogether 50 of 11,461, 24 of 10,093, and 17 of 11,218 children surveyed during 1989, 1990, and 1991 respectively had become lame as a result of poliomyelitis, giving prevalences of 4.4, 2.4, and 1.5 per 1000 children for the three surveys. The corrected prevalences of poliomyelitis were 5.9, 3.2, and 2.0 per 1000 children during 1989, 1990, and 1991 respectively. The proportion of cases aged up to 36 months fell from 48% in 1989 to 12.5% in 1990 and 6% in 1991. The age at onset was less than 1 year in most. The median age at onset was 10.7 months. About 54% of the affected children had received three doses of oral poliomyelitis vaccine (OPV) before the onset of paralysis. In 1988 immunisation coverage for the third dose of OPV was 91% and in 1992 it was 97.6%. The drop out rate for the first versus the third dose of OPV fell from 6.3 in 1988 to 1.9% in 1992. CONCLUSION: Three successive annual lameness surveys showed that poliomyelitis was declining between 1989 and 1991. Five immunisation coverage surveys conducted from 1988 to 1992 showed high initial coverage followed by an improvement in the form of almost universal coverage for OPV. 相似文献
10.
Ramanathan Sundar Varma Shashi Kumar Rao Kolli Madhusudana Muralidharan Srinivasan 《Indian Journal of Thoracic and Cardiovascular Surgery》2004,20(4):164-166
Background Extended trans septal (ETS) approach for mitral valve surgery often divides the artery to the Sino-Atrial node. The clinical
implication of this is contentious. We analyzed our early results with ETS approach.
Methods Between June 1998 and September 2003 eleven patients underwent mitral valve surgery by ETS approach. Six were females. Age
ranged from 19 years to 67 years (median 40 years). Six underwent mitral valve replacement (MVR). Four underwent aortic and
mitral (double) valve replacement (DVR). One had mitral valve repair. Three had additional procedures (tricuspid valve repair=1,
Coronary artery bypass=1, Aorto bifemoral graft=1). Cardiopulmonary bypass ranged from 64 minutes to 77 minutes (median 72
minutes) for MVR and 112 minutes to 178 minutes (median 140 minutes) for DVR. Aortic cross clamp times ranged from 39 minutes
to 52 minutes (median 47 minutes) for MVR and 74 minutes to 120 minutes (median 95 minutes) for DVR.
Results There was no mortality or morbidity attributed to the ETS approach. One early death in emergency DVR was due to heart failure.
Three patients needed seqeuntial pacing in the immediate post-operative period. Nine out of ten survivors were back to their
preoperative rhythms on hospital discharge (6 sinus rhythm; 3 atrial fibrillation). One patient with preoperative trifascicular
block who underwent reoperation to fix a paravalvular mitral leak needed a permanent pacemaker (VVI). The follow-up ranged
from 1 month to 64 months (median 6 months) and is 100% complete. There was no late death or new arrhythmia.
Conclusions Extended trans septal approach is safe. It gives excellent exposure of the mitral valve. division of the sinus node artery
is not deleterious in the short to intermediate term.
Presented at the 50th Annual Meeting of IACTS. New Delhi, Feb. 2004. 相似文献