全文获取类型
收费全文 | 1901篇 |
免费 | 108篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 47篇 |
儿科学 | 107篇 |
妇产科学 | 94篇 |
基础医学 | 187篇 |
口腔科学 | 152篇 |
临床医学 | 172篇 |
内科学 | 443篇 |
皮肤病学 | 25篇 |
神经病学 | 140篇 |
特种医学 | 114篇 |
外科学 | 213篇 |
综合类 | 38篇 |
一般理论 | 1篇 |
预防医学 | 55篇 |
眼科学 | 56篇 |
药学 | 107篇 |
中国医学 | 3篇 |
肿瘤学 | 64篇 |
出版年
2024年 | 4篇 |
2023年 | 36篇 |
2022年 | 60篇 |
2021年 | 109篇 |
2020年 | 57篇 |
2019年 | 73篇 |
2018年 | 85篇 |
2017年 | 73篇 |
2016年 | 85篇 |
2015年 | 90篇 |
2014年 | 108篇 |
2013年 | 119篇 |
2012年 | 143篇 |
2011年 | 169篇 |
2010年 | 74篇 |
2009年 | 65篇 |
2008年 | 130篇 |
2007年 | 118篇 |
2006年 | 91篇 |
2005年 | 104篇 |
2004年 | 88篇 |
2003年 | 58篇 |
2002年 | 49篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1990年 | 1篇 |
排序方式: 共有2018条查询结果,搜索用时 15 毫秒
71.
Elif Sargin Altunok Celal Satici Veysel Dinc Sadettin Kamat Mustafa Alkan Mustafa Asim Demirkol Ilkim Deniz Toprak Muhammed Emin Kostek Semih Yazla Sinem Nihal Esatoglu 《Journal of medical virology》2022,94(1):291-297
Due to current advances and growing experience in the management of coronavirus Disease 2019 (COVID-19), the outcome of COVID-19 patients with severe/critical illness would be expected to be better in the second wave compared with the first wave. As our hospitalization criteria changed in the second wave, we aimed to investigate whether a favorable outcome occurred in hospitalized COVID-19 patients with only severe/critical illness. Among 642 laboratory-confirmed hospitalized COVID-19 patients in the first wave and 1121 in the second wave, those who met World Health Organization (WHO) definitions for severe or critical illness on admission or during follow-up were surveyed. Data on demographics, comorbidities, C-reactive protein (CRP) levels on admission, and outcomes were obtained from an electronic hospital database. Univariate analysis was performed to compare the characteristics of patients in the first and second waves. There were 228 (35.5%) patients with severe/critical illness in the first wave and 681 (60.7%) in the second wave. Both groups were similar in terms of age, gender, and comorbidities, other than chronic kidney disease. Median serum CRP levels were significantly higher in patients in the second wave compared with those in the first wave [109 mg/L (interquartile range [IQR]: 65–157) vs. 87 mg/L (IQR: 39–140); p < 0.001]. However, intensive care unit admission and mortality rates were similar among the waves. Even though a lower mortality rate in the second wave has been reported in previous studies, including all hospitalized COVID-19 patients, we found similar demographics and outcomes among hospitalized COVID-19 patients with severe/critical illness in the first and second wave. 相似文献
72.
In this study, Doppler signals recorded from ophthalmic artery of 75 subjects were processed by PC-computer using classical and model-based methods. The classical method (fast Fourier transform) and three model-based methods (Burg autoregressive, moving average, least-squares modified Yule–Walker autoregressive moving average methods) were selected for processing ophthalmic arterial Doppler signals with uveitis disease. Doppler power spectra of ophthalmic arterial Doppler signals were obtained by using these spectrum analysis techniques. The variations in the shape of the Doppler spectra as a function of time were presented in the form of sonograms in order to obtain medical information. These Doppler spectra and sonograms were then used to compare the applied methods in terms of their frequency resolution and the effects in determination of uveitis disease. 相似文献
73.
Altas E Ertekin MV Gundogdu C Demirci E 《Annals of clinical and laboratory science》2006,36(3):312-318
L-carnitine (LC) protects cells from peroxidative damage. In this study, we tested whether L-carnitine (LC) prevents radiation-induced cochlear damage after total cranial irradiation (radiotherapy; RT). Male albino guinea pigs were randomly distributed in 3 groups. The Control group (n = 11) received neither LC nor irradiation, but saline solution ip and sham irradiation for 5 days. The RT group (n = 32) received saline solution ip as placebo therapy and exposure to total cranial irradiation of 33 Gy in 5 fractions of 6.6 Gy/day on 5 successive days, with a calculated (alpha/beta = 3.5) biological effective dose of fractionated irradiation equal to 60 Gy conventional fractionation. The LC + RT group (n = 36) received total cranial irradiation, plus LC (100 mg/kg/day, ip) for 5 days. The guinea pigs were killed at 4, 24, or 96 hr after the last dose of RT and the cochleas were enucleated for histopathologic examination. There was no cochlear degeneration in the control group. In the RT group, total cranial irradiation caused degeneration in stria vascularis (SV), spiral ganglion (SG), outer hair cells (OHC), and inner hair cells (IHC) of cochleas at 4, 24, and 96 hr. In the LC + RT group, LC administration reduced radiation-induced cochlear degeneration in SV and SG at 4, 24, and 96 hr, and in OHC and IHC at 24 and 96 hr (p <0.05). Thus, this study shows that L-carnitine can ameliorate radiation-induced cochlear damage in guinea pigs. 相似文献
74.
Natalia Kriuchkova Tilman Breiderhoff Dominik Müller Duygu Elif Yilmaz Hasan Demirci Hoora Drewell Dorothee Günzel Nina Himmerkus Markus Bleich Pontus B. Persson Kerim Mutig 《Acta physiologica (Oxford, England)》2023,237(3):e13927
Aim
Perturbed calcium homeostasis limits life expectancy in familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC). This rare disease occurs by loss-of-function mutations in CLDN16 or CLDN19 genes, causing impaired paracellular reabsorption of divalent cations along the cortical thick ascending limb (cTAL). Only partial compensation takes place in the ensuing late distal convoluted tubule, connecting tubule, and collecting duct, where the luminal transient receptor potential channel V5 (TRPV5), as well as basolateral plasma membrane calcium ATPase (PMCA) and sodium-potassium exchanger (NCX1) mediate transcellular Ca2+ reabsorption. The loop diuretic furosemide induces compensatory activation in these distal segments. Normally, furosemide enhances urinary calcium excretion via inhibition of the aforementioned cTAL. As Ca2+ reabsorption in the cTAL is already severely impaired in FHHNC patients, furosemide may alleviate hypercalciuria in this disease by activation of the distal transcellular Ca2+ transport proteins.Methods
Cldn16-deficient mice (Cldn16−/−) served as a FHHNC model. Wild-type (WT) and Cldn16−/− mice were treated with furosemide (7 days of 40 mg/kg bw) or vehicle. We assessed renal electrolyte handling (metabolic cages) and key divalent transport proteins.Results
Cldn16−/− mice show higher Ca2+ excretion than WT and compensatory stimulation of Cldn2, TRPV5, and NCX1 at baseline. Furosemide reduced hypercalciuria in Cldn16−/− mice and enhanced TRPV5 and PMCA levels in Cldn16−/− but not in WT mice.Conclusions
Furosemide significantly reduces hypercalciuria, likely via upregulation of luminal and basolateral Ca2+ transport systems in the distal nephron and collecting duct in this model for FHHNC. 相似文献75.
Yavuz Simsek Mehmet Gul Ercan Yilmaz Ibrahim Halil Ozerol Elif Ozerol Hakan Parlakpinar 《Archives of gynecology and obstetrics》2014,290(5):999-1006
Purpose
The purpose of this study was to examine the effects of atorvastatin in the treatment of experimental endometriosis.Methods
Endometriosis was induced in 24 female rats. 4 weeks after the procedure dimensions of the foci were recorded. Rats were divided into three groups: in Group 1 (n = 8), a daily dose of 10 mg/kg atorvastatin was given for 14 days. In the second group (n = 8), a single dose of 1 mg/kg leuprolide acetate was injected intraperitoneally. The rats in Group 3 (n = 8) were received 1 mg/kg i.p. 0.9 % NaCl. At the end of the treatment, laparotomy was performed, and the dimensions of the endometriotic foci were recorded. Biochemical, histopathological and immunohistochemical studies were performed and nociception was compared in groups.Results
Atorvastatin treatment exhibited significant analgesic activity in hot plate model (P = 0.022). The serum hs-CRP and tumor necrosis TNF-α levels were similar between the Group 2 and Group 3 (P > 0.05); however atorvastatin caused significant decrease in both serum markers. The histological and immunohistochemical scores were also found to be markedly lower in Group 1 and Group 2 (P < 0.05).Conclusion
Atorvastatin treatment may have a therapeutic potential in the treatment of endometriosis through its anti-inflammatory and anti-nociceptive properties. 相似文献76.
Elif Aydogan Ayaz Rukiye Durkan Bora Bagis 《The journal of advanced prosthodontics》2013,5(2):110-117
PURPOSE
Polymethyl methacrylate (PMMA) is the most commonly used denture base material despite typically low in strength. The purpose of this study was to improve the physical properties of the PMMA based denture base resins (QC-20, Dentsply Ltd., Addlestone, UK; Stellon, AD International Ltd, Dentsply, Switzerland; Acron MC; GC Lab Technologies Inc., Alsip, Japan) by copolymerization mechanism.MATERIALS AND METHODS
Control group specimens were prepared according to the manufacturer recommendations. In the copolymer groups; resins were prepared with 5%, 10%, 15% and 20% acrylamide (AAm) (Merck, Hohenbrunn, Germany) content according to the moleculer weight ratio, respectively. Chemical structure was characterized by a Bruker Vertex-70 Fourier transform infrared spectroscopy (FTIR) (Bruker Optics Inc., Ettlingen, Germany). Hardness was determined using an universal hardness tester (Struers Duramin, Struers A/S, Ballerup, Denmark) equipped with a Vickers diamond penetrator. The glass transition temperature (Tg) of control and copolymers were evaluated by Perkin Elmer Diamond DSC (Perkin Elmer, Massachusetts,USA). Statistical analyses were carried out using the statistical package SPSS for Windows, version 15.0 (SPSS, Chicago, IL, USA). The results were tested regarding the normality of distribution with the Shapiro Wilk test. Data were analyzed using ANOVA with post-hoc Tukey test (P<.01).RESULTS
The copolymer synthesis was confirmed by FTIR spectroscopy. Glass transition temperature of the copolymer groups were higher than the control groups of the resins. The 10%, 15% and 20% copolymer groups of Stellon presented significantly higher than the control group in terms of hardness. 15% and 20% copolymer groups of Acron MC showed significantly higher hardness values when compared to the control group of the resin. Acrylamide addition did not affect the hardness of the QC-20 resin significantly.CONCLUSION
Within the limitation of this study, it can be concluded that copolymerization of PMMA with AAm increased the hardness value and glass transition temperature of PMMA denture base resins. 相似文献77.
Hikmet Aydemir G?zlem Ceylan Tamer Tasdemir Elif Kalyoncuoglu Ibrahim Isildak 《Journal of applied oral science : revista FOB》2009,17(6):605-610
During mechanical preparation of the post space, the root canal filling may be twisted or vibrated, depending on several factors associated with the preparation technique and quality of filling.
Objective:
The purpose of this study was to investigate the effect of immediate and delayed post space preparation on the integrity of the apical seal.Material and Methods:
Sixty-four extracted human incisors were biomechanically prepared using the step-back technique. Sixty roots were randomly assigned to 6 experimental groups of 10 teeth each and the remaining 4 roots served as positive and negative controls (n=2). The root canals in the different groups were obturated with cold lateral and warm vertical condensation of gutta-percha and one of two sealers (Sealapex and Diaket). Post space was prepared either individually or simultaneously. An insulated copper wire was cut into 10-cm-long pieces. In each canal, one piece was inserted to maintain contact with gutta-percha and extended to the outside as one of two working electrodes. A stainless steel wire with the same dimensions of those of the copper wire, used as the other working electrode, was immersed into the background electrolyte from the center of the bottle. The electrical current between standard and experimental electrodes in canals was measured over a period of 10 days applying a conductivity meter. The Kruskal-Wallis test (p=0.05) determined whether there was a significant difference in microleakage among the groups and the Mann-Whitney U test (p=0.01) was used for multiple comparison grouping variables.Results:
The results suggest that only the differences between the root canal filling techniques were statistically significant (p<0.01). There were no statistically significant difference in the sealers and the times of filling removal for post space preparation (p>0.01).Conclusion:
The quality of the root canal filling is important for the integrity of the apical seal. 相似文献78.
Elif Figen Koçak Yurdanur Uçar Cem Kurtoğlu William M. Johnston 《The Journal of prosthetic dentistry》2019,121(3):510-516
Statement of problem
A good color match combined with a proper translucency match results in excellent esthetics for a metal-free restoration, yet basic color and translucency comparisons between available zirconia systems are not well described.Purpose
The purpose of this in vitro study was to compare the color and translucency of commercially available zirconia materials.Material and methods
Eight specimen disks were formed in each of the single-layer (0.5-mm thick) groups and double-layer (0.5-mm zirconia with 1.0-mm porcelain) groups for each of 5 zirconia-based substructure systems. Colors on black, gray, and white backings were used to obtain CIEDE2000 color differences between the zirconia systems in the layering groups and to obtain relative translucency parameter (RTP) values. Color differences were compared with perceptibility and acceptability thresholds, and comparisons in RTP were made using analyses of variance and the Bonferroni corrected Student t tests (α=.05).Results
The Shrout-Fleiss random set reliability for the duplicate L* determinations was 0.9992, 0.9756 for a*, and 0.9959 for b*. Although some mean color differences were below or at the perceptibility threshold, most differences were at or above the acceptability threshold. For the single-layer configuration, 1 material system had higher RTP values than every other material (P<.001), and another material had lower RTP values than every other material (P<.001).Conclusions
The results of this study present significant differences in both color and translucency among 5 ceramic substrate systems when studied in single layers. Perceivable and often unacceptable differences in color were also found among these materials when layered with porcelain. It is concluded that the esthetics of restorations which use a ceramic substrate is notably affected by the ceramic system used. 相似文献79.
Ulu EM Tarhan NC Hocaoglu E Akman B Basaran C Donmez FY Niron EA 《European journal of radiology》2009,72(2):306-313
As a consequence of the expanded use of long term hemodialysis and continuous ambulatory peritoneal dialysis (CAPD) treatments and extended life spans, complications of end-stage renal disease and dialysis treatments are being encountered with increasing frequency in these patients. Computed tomography can accurately depict many of the potential complications of end-stage renal disease on dialysis. This article presents the abdominal CT findings of 429 end-stage renal disease patients who are on either hemodialysis or continuous ambulatory peritoneal dialysis treatment. 相似文献
80.
Elif Özalkaya Sevilay Topcuoglu Hande Karatepe Abdülhamit Tüten Tulin Gokmen Guner Karatekin 《The journal of maternal-fetal & neonatal medicine》2013,26(24):4093-4096
AbstractObjective: To evaluate levetiracetam (LEV) efficacy in preterm infants admitted in NICU.Study design: Clinical characteristics of 26 preterm infants treated with LEV were evaluated retrospectively. The results were compared with those of 44 preterm infants from the literature who were given LEV.Result: The mean gestational week of the infants receiving LEV was found as 26.7?±?3.3 weeks, mean birth weight as 938?±?561?g and mean dose of LEV as 17?±?9.23?mg/kg. Overall seizure control rate with LEV was found as 65%, while seizure control was achieved by 11.5% when it was used as the first drug, 35% as the second drug and 15.3% as the third drug. The incidence of sepsis and intraventricular hemorrhage in seizure etiology was 73% in infants who received LEV. There was no side effect observed during LEV treatment.Conclusions: Seizure control was better achieved with LEV given as the 2nd antiepileptic in premature infants. Further studies with randomization of LEV and other antiepileptics in seizure control are needed. 相似文献