全文获取类型
收费全文 | 671篇 |
免费 | 57篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 18篇 |
妇产科学 | 28篇 |
基础医学 | 130篇 |
口腔科学 | 9篇 |
临床医学 | 69篇 |
内科学 | 130篇 |
皮肤病学 | 6篇 |
神经病学 | 60篇 |
特种医学 | 15篇 |
外科学 | 48篇 |
综合类 | 9篇 |
预防医学 | 49篇 |
眼科学 | 10篇 |
药学 | 110篇 |
1篇 | |
中国医学 | 14篇 |
肿瘤学 | 23篇 |
出版年
2023年 | 2篇 |
2022年 | 13篇 |
2021年 | 17篇 |
2020年 | 15篇 |
2019年 | 19篇 |
2018年 | 16篇 |
2017年 | 14篇 |
2016年 | 20篇 |
2015年 | 26篇 |
2014年 | 37篇 |
2013年 | 32篇 |
2012年 | 61篇 |
2011年 | 62篇 |
2010年 | 30篇 |
2009年 | 32篇 |
2008年 | 56篇 |
2007年 | 41篇 |
2006年 | 39篇 |
2005年 | 38篇 |
2004年 | 29篇 |
2003年 | 18篇 |
2002年 | 13篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 11篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1969年 | 1篇 |
1927年 | 1篇 |
排序方式: 共有730条查询结果,搜索用时 31 毫秒
21.
V.K. Malhotra Navreet Singh R.S. Bishnoi D.S. Chadha P. Bhardwaj H. Madan R. Dutta A.K. Ghosh S. Sengupta P. Perumal 《Medical Journal Armed Forces India》2015,71(4):324-329
Background
Competitive sports training causes structural and conductive system changes manifesting by various electrocardiographic alterations. We undertook this study to assess the prevalence of abnormal ECG in trained Indian athletes and correlate it with the nature of sports training, that is endurance or strength training.Methods
We evaluated a standard resting, lying 12 lead Electrocardiogram (ECG) in 66 actively training Indian athletes. Standard diagnostic criteria were used to define various morphological ECG abnormalities.Results
33/66 (50%) of the athletes were undertaking endurance training while the other 33 (50%) were involved in a strength-training regimen. Overall 54/66 (81%) sportsmen had significant ECG changes. 68% of these changes were considered as normal training related features, while the remaining 32% were considered abnormal. There were seven common training related ECG changes–Sinus Bradycardia (21%), Sinus Arrhythmia (16%), 1st degree Atrioventricular Heart Block (6%), Type 1 2nd-degree Atrioventicular Heart Block (3%), Incomplete Right bundle branch block (RBBB) (24%), Early Repolarization (42%), Left Ventricular Hypertrophy (LVH) (14%); while three abnormal ECG changes--T-wave inversion (13%), RBBB(4%), Right ventricular hypertrophy (RVH) with strain (29%) were noted. Early repolarization (commonest change), sinus bradycardia, and incomplete RBBB were the commoner features noticed, with a significantly higher presence in the endurance trained athletes.Conclusion
A high proportion of athletes undergoing competitive level sports training are likely to have abnormal ECG recordings. Majority of these are benign, and related to the physiological adaptation to the extreme levels of exertion. These changes are commoner during endurance training (running) than strength training (weightlifting). 相似文献22.
Ahmed S. BaHammam Khalid Almushailhi Seithikurippu R. Pandi‐Perumal Munir M. Sharif 《Journal of sleep research》2014,23(1):35-43
Islamic intermittent fasting is distinct from regular voluntary or experimental fasting. We hypothesised that if a regimen of a fixed sleep–wake schedule and a fixed caloric intake is followed during intermittent fasting, the effects of fasting on sleep architecture and daytime sleepiness will be minimal. Therefore, we designed this study to objectively assess the effects of Islamic intermittent fasting on sleep architecture and daytime sleepiness. Eight healthy volunteers reported to the Sleep Disorders Centre on five occasions for polysomnography and multiple sleep latency tests: (1) during adaptation; (2) 3 weeks before Ramadan, after having performed Islamic fasting for 1 week (baseline fasting); (3) 1 week before Ramadan (non‐fasting baseline); (4) 2 weeks into Ramadan (Ramadan); and (5) 2 weeks after Ramadan (non‐fasting; Recovery). Daytime sleepiness was assessed using the Epworth Sleepiness Scale and the multiple sleep latency test. The participants had a mean age of 26.6 ± 4.9 years, a body mass index of 23.7 ± 3.5 kg m?2 and an Epworth Sleepiness Scale score of 7.3 ± 2.7. There was no change in weight or the Epworth Sleepiness Scale in the four study periods. The rapid eye movement sleep percentage was significantly lower during fasting. There was no difference in sleep latency, non‐rapid eye movement sleep percentage, arousal index and sleep efficiency. The multiple sleep latency test analysis revealed no difference in the sleep latency between the ‘non‐fasting baseline’, ‘baseline fasting’, ‘Ramadan’ and ‘Recovery’ time points. Under conditions of a fixed sleep–wake schedule and a fixed caloric intake, Islamic intermittent fasting results in decreased rapid eye movement sleep with no impact on other sleep stages, the arousal index or daytime sleepiness. 相似文献
23.
M. Judith Percino Margarita Cern Perumal Venkatesan Enrique Prez-Gutirrez Pilar Santos Paulina Ceballos Armando E. Castillo Paola Gordillo-Guerra Karnambaram Anandhan Oracio Barbosa-García Wilson Bernal Subbiah Thamotharan 《RSC advances》2019,9(49):28704
2-(4-((2-Hydroxyethyl)(methyl)amino)benzylidene)malononitrile (HEMABM) was synthesized from 4-[hydroxymethyl(methyl)amino]benzaldehyde and propanedinitrile to obtain a low molecular weight fluorescent material with an efficient solid-state emission and electroluminescence properties comparable to the well-known poly(2-methoxy-5(2′-ethyl)hexoxyphenylenevinylene) (MEH-PPV). The HEMABM was used to prepare an organic light-emitting diode by a solution process. Despite the title compound being a small molecule, it showed optical properties and notable capacity to form a film with smooth morphology (10.81 nm) closer to that of polymer MEH-PPV (10.63 nm). The preparation of the device was by spin coating, the electrical properties such as threshold voltage were about 1.0 V for both HEMABM and MEH-PPV, and the luminance 1300 cd m−2 for HEMABM and 2600 cd m−2 for MEH-PPV. This low molecular weight compound was characterized by SCXRD, IR, NMR, and EI. Besides a quantitative analysis of the intermolecular interactions by PIXEL, density functional theory (DFT) calculations are reported.A low molecular weight fluorescent malononitrile derivative showed an efficient solid-state emission and electroluminescence properties. 相似文献
24.
Thirunavukkarasu Santhoshkumar Abdul Abdul Rahuman Chidambaram Jayaseelan Govindasamy Rajakumar Sampath Marimuthu Arivarasan Vishnu Kirthi Kanayairam Velayutham John Thomas Jayachandran Venkatesan Se-Kwon Kim 《Asian Pacific journal of tropical medicine》2014,7(12):968-976
Objective:To determine the efficacies of antibacterial and antioxidant activities of aqueous leaf extract of Psidium guajava mediated biosynthesis of titanium dioxide nanoparticles(TiO_2,NPs).Methods:Synthesized TiO_2 NPs were tested by disc diffusion method against against human pathogenic bacteria.The total antioxidant activity and phenolic content(Folin—Ciocalteau method) of synthesized TiO_2 NTs and aqueous plant extract were determined.The scavenging radicals were estimated hv DPPH method.The synthesized TiO_2 NPs were characterized by XRD,FTIR.FESEM and EDX,Results:FTIR spectra of synthesized TiO_2 NPs exhibited prominent peaks at 3410 cm~(-1)(alkynes),1 578 cm~(-1).1 451 cm~(-1)(alkanes),and 1 123 cm~(-1)(C-O absorption).The morphological characterization of synthesized TiO_2 NPs was analysed by FESEM which showed spherical shape and clusters with an average size of 32.58 nm.The maximum zone of inhibition was observed in the synthesized TiO_2 NPs(20 μg/mL) against Staphylococcus aureus(25 mm) and Escherichia coli(23 mm).The synthesized TiO_2 NPs showed more antibacterial activity than the standard antibiotic disk,tetracycline which drastically reduces the chances for the development of antibiotics resistance of bacterial species.The plant aqueous extract and synthesized TiO_2NPs were found to possess maximum antioxidant activity when compared with ascorbic acid.The content of phenolic compounds(mg/g) in Leaf aqueous extract and synthesized TiO_2 NPs were found to be 85.4 and 18.3 mgTA/g,respectively.Conclusions:Green synthesized TiO_2 NPs provides a promising approach can satisfy the requirement of large-scale industrial production hearing the advantage of low—cost,eco—friendly and reproducible. 相似文献
25.
Imayavaramban Lakshmanan Sanjib Chaudhary Raghupathy Vengoji Parthasarathy Seshacharyulu Satyanarayana Rachagani Joseph Carmicheal Rahat Jahan Pranita Atri Ramakanth ChirravuriVenkata Rohitesh Gupta Saravanakumar Marimuthu Naveenkumar Perumal Sanchita Rauth Sukhwinder Kaur Kavita Mallya Lynette M. Smith Subodh M. Lele Moorthy P. Ponnusamy Mohd W. Nasser Ravi Salgia Surinder K. Batra Apar Kishor Ganti 《Molecular oncology》2021,15(7):1866
26.
D. Santhanaraj N. Ricky Joseph V. Ramkumar A. Selvamani I. P. Bincy K. Rajakumar 《RSC advances》2020,10(64):39146
In this study, 8, 25 and 50 wt% Fe3O4@activated carbon (AC) catalysts were prepared by simple coprecipitation method. The efficiency of the catalysts for the advanced Fenton''s oxidation process using methylene blue (MB) as a model substrate was tested. Both modified and unmodified activated carbon catalysts exhibited similar activity towards the Fenton''s oxidation process. Therefore, it is difficult to identify the role of the catalyst in this dye removal process. Hence, we proposed a new methodology to remove the MB by adopting the adsorption process initially, followed by the Fenton''s oxidation process. The proposed process significantly improved the methylene blue decomposition reaction over the 25 wt% Fe3O4@AC catalyst. However, this trend was not seen in pure activated carbon and Fe3O4@AC (8 and 50 wt%) catalysts due to the instability of the material in the oxidizing medium. The possible reason for the deactivation of the catalysts was evaluated from lattice strain calculations, as derived from the modified W–H models (Uniform Deformational Model (UDM), Uniform Stress Deformation Model (USDM) and Uniform Deformation Energy Density Model (UDEDM)). These results provided a quantitative relationship between the experimentally calculated lattice strain values and Fenton''s catalytic activity. Furthermore, the optimized strain value and crystalite size of Fe3O4 on the activated carbon matrix are responsible for the high catalytic activity.The activity of the catalyst was directly correlated using lattice strain calculations, as derived from the W–H model. 相似文献
27.
Nandita Perumal Daniel E. Roth Johnna Perdrizet Aluísio J. D. Barros Iná S. Santos Alicia Matijasevich Diego G. Bassani 《Emerging themes in epidemiology》2018,15(1):3
Background
Postmenstrual and/or gestational age-corrected age (CA) is required to apply child growth standards to children born preterm (< 37 weeks gestational age). Yet, CA is rarely used in epidemiologic studies in low- and middle-income countries (LMICs), which may bias population estimates of childhood undernutrition. To evaluate the effect of accounting for GA in the application of growth standards, we used GA-specific standards at birth (INTERGROWTH-21st newborn size standards) in conjunction with CA for preterm-born children in the application of World Health Organization Child Growth Standards postnatally (referred to as ‘CA’ strategy) versus postnatal age for all children, to estimate mean length-for-age (LAZ) and weight-for-age (WAZ) z scores at 0, 3, 12, 24, and 48-months of age in the 2004 Pelotas (Brazil) Birth Cohort.Results
At birth (n = 4066), mean LAZ was higher and the prevalence of stunting (LAZ < ?2) was lower using CA versus postnatal age (mean ± SD): ? 0.36 ± 1.19 versus ? 0.67 ± 1.32; and 8.3 versus 11.6%, respectively. Odds ratio (OR) and population attributable risk (PAR) of stunting due to preterm birth were attenuated and changed inferences using CA versus postnatal age at birth [OR, 95% confidence interval (CI): 1.32 (95% CI 0.95, 1.82) vs 14.7 (95% CI 11.7, 18.4); PAR 3.1 vs 42.9%]; differences in inferences persisted at 3-months. At 12, 24, and 48-months, preterm birth was associated with stunting, but ORs/PARs remained attenuated using CA compared to postnatal age. Findings were similar for weight-for-age z scores.Conclusions
Population-based epidemiologic studies in LMICs in which GA is unused or unavailable may overestimate the prevalence of early childhood undernutrition and inflate the fraction of undernutrition attributable to preterm birth.28.
Sriramoju Bharath Kumar Mettu Ravinder Golla Kishore Vaidya Jayathirtha Rao Perumal Yogeeswari Darmarajan Sriram 《Medicinal chemistry research》2014,23(4):1934-1940
Baylis–Hillman adduct-derived N-cinnamyl-substituted isatin derivatives were synthesized and evaluated for their antitubercular activity on Mycobacterium tuberculosis H37Rv strain ATCC 27294 by agar dilution method. Anticancer activity for the same compounds was also screened on four different cell lines: Chinese hamster ovary (CHO cells), Colo 205 (human colon cancer), Sup-T1 (human lymphoma) and C6 glioma (rat glioma) by MTT assay method. The compounds (3j–l) have shown significant activity against Mycobacterium strain and the compound 3l has shown specific cytotoxic activity. 相似文献
29.
Mishra Sumit Ranjan Yadav Pavan Kumar Nandhakumar Perumal Saini Mohini Kumar Ajay Kataria Meena 《Proceedings of the National Academy of Sciences, India. Section B.》2019,89(2):511-515
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - The anti-metastatic activity of bacosine (Bacopa monnieri plant) was studied using 4T1 murine breast cancer... 相似文献
30.
Objective:To assess the accuracy of the clinically estimated blood loss (EBL) when compared with the actual blood loss (ABL) in replacement surgeries.Methods:This prospective study was done in Sri Ramachandra Medical Centre from April 2011 to April 2013.Altogether 140 patients undergoing total hip replacement or total knee replacement were included with the inclusion criteria being patients with haemoglobin higher than 100 g/ml and coagulation profile within normal limits.Exclusion criteria were intake of antiplatelet drug or anti-coagulant,bleeding disorders,thrombotic episode,and haematological disorders.There were 65 men and 75 women.In this study,the consultants were free to use any clinical method to estimate the blood loss,including counting the blood-soaked mops and gauze pieces (estimating the volume of blood carded in all the mops and gauzes),measuring blood lost to suction bottles and blood in and around the operative field.The ABL was calculated based on a modification of the Gross's formula using haematocrit values.Results:In 42 of the 140 cases,the EBL exceeded the ABL.These cases had a negative difference in blood loss (or DIFF-BL<0) and were included in the overestimation group,which accounted for 30% of the study population.Of the remaining 98 cases (70%),the ABL exceeded the EBL.Therefore they were put into the underestimation group who had a positive difference in blood loss (DIFF-BL>0).We found that when the average blood loss was small,the accuracy of estimation was high.But when the average blood loss exceeded 500 ml,the accuracy rate decreased significantly.This suggested that clinical estimation is inaccurate with the increase of blood loss.Conclusion:This study has shown that using clinical estimation alone to guide blood transfusion is inadequate.In this study,70% of patients had their blood loss underestimated,proving that surgeons often underestimate blood loss in replacement surgeries. 相似文献