全文获取类型
收费全文 | 1979篇 |
免费 | 130篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 68篇 |
儿科学 | 51篇 |
妇产科学 | 93篇 |
基础医学 | 196篇 |
口腔科学 | 67篇 |
临床医学 | 207篇 |
内科学 | 344篇 |
皮肤病学 | 36篇 |
神经病学 | 115篇 |
特种医学 | 68篇 |
外科学 | 266篇 |
综合类 | 48篇 |
预防医学 | 152篇 |
眼科学 | 66篇 |
药学 | 199篇 |
中国医学 | 40篇 |
肿瘤学 | 109篇 |
出版年
2024年 | 4篇 |
2023年 | 31篇 |
2022年 | 83篇 |
2021年 | 107篇 |
2020年 | 78篇 |
2019年 | 92篇 |
2018年 | 103篇 |
2017年 | 88篇 |
2016年 | 73篇 |
2015年 | 80篇 |
2014年 | 96篇 |
2013年 | 110篇 |
2012年 | 155篇 |
2011年 | 143篇 |
2010年 | 78篇 |
2009年 | 62篇 |
2008年 | 122篇 |
2007年 | 88篇 |
2006年 | 93篇 |
2005年 | 68篇 |
2004年 | 61篇 |
2003年 | 58篇 |
2002年 | 53篇 |
2001年 | 21篇 |
2000年 | 16篇 |
1999年 | 18篇 |
1998年 | 12篇 |
1997年 | 12篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 13篇 |
1989年 | 10篇 |
1988年 | 11篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1969年 | 2篇 |
1928年 | 1篇 |
排序方式: 共有2125条查询结果,搜索用时 15 毫秒
81.
Rokni-Yazdi H Azmoudeh Ardalan F Asadzandi Z Sotoudeh H Shakiba M Adibi A Ayatollahi H Rahmani M 《European journal of radiology》2009,70(1):10-16
Objective
The exact nature of the “dural tail sign” (thickening of the dura adjacent to the tumour in contrast enhanced T1-MRI imaging) is still not clearly established. In this study we tried to verify the histological appearance of the “dural tail sign” and probable correlation between different MRI findings and dural tail histology.Material and methods
In this study, 129 patients with intracranial lesions underwent MRI imaging with 1.5 T scanner. The “dural tail sign” was defined using Goldsher et al. criteria. Size and pattern of enhancement of the tumour and adjacent dura was noted in MRI and in the pathologic samples, dural tail and the dura beneath the tumour was assessed.Results
In 30 cases, “dural tail sign” was evident on MRI, dural tail noted in 17 of these cases in histological samples (12 meningiomas, 3 pituitary adenomas and 2 schwannomas). All of them had vessel dilatation, 6 showed tumoural invasion, 4 demonstrated intravascular growth of the lesion and 1 showed inflammation of the dura.Conclusion
In our study MRI findings failed to predict tumoural invasion of the dural tail in histologic samples and because of frequent presence of tumour nests in it, the dura matter should be resected as widely as possible. 相似文献82.
Dr. M. Gubina Prof. J. Zajc-Satler Prof. J. Mehle Prof. B. Drinovec Dr. F. Pikelj Prof. A. Radšel-Medvešček Dr. M. Suhač 《Infection》1976,4(2):115-118
Summary Two cases of infection with Campylobacter fetus subspecies intestinalis are reported. In a 46-year-old farmer the development of septicaemic campylobacteriosis with acute gastroenterocolitis was favoured by malnutrition due to chronic alcoholism. After treatment with erythromycin the patient recovered completely. The second patient, a 40-year-old worker with meningitis, recovered after combined streptomycin-erytromycin therapy. In both patients antibiodies against homologous and reference strains of Campylobycter fetus subspecies intestinalis, serotype 1 (Mitscherlich) were demonstrated in titres ranging from 1 : 16 to 1 : 64 by type the complement-fixation test.
Sepsis und Meningitis durch Campylobacter fetus Subspezies intestinalis
Zusammenfassung Zwei Fälle von Campylobacter fetus-Infektion mit Sepsis und Meningitis wurden beobachtet. Bei einem 46jährigen Bauern wurde eine septische Campylobacteriosis durch extreme Mangelernährung infolge von chronischem Alkoholismus begünstigt. Die Therapie mit Erythromycin war erfolgreich. Der andere Patient war ein 40jähriger Arbeiter mit Meningitis; auch dieser hat nach einer kombinierten Erythromycin- und Streptomycinkur das Krankenhaus gesund verlassen. Das Serumantikörpertiter war 1 : 16 bis 1 :64 in der Komplementbindungsreaktion gegen Homologe und Referenzstämme der Campylobacter fetus subspecies intestinalis serotype I (Mitscherlich).相似文献
83.
Mahmoud Torabinejad Hadi FarasRobert Corr DDS MSD Kenneth R. WrightShahrokh Shabahang DDS MS PhD 《Journal of endodontics》2014
Introduction
A growing body of evidence is building a case for the possibility of tissue regeneration within the root canal of necrotic teeth, allowing for continued root development. However, it remains unknown what type of tissue is produced after regenerative endodontics. The purpose of this study was to use blood clots and platelet-rich plasma (PRP) as scaffolds in regenerative endodontics under ideal conditions in a ferret model to examine the tissues generated within the root canals.Methods
The pulps of 21 canine teeth from 7 young ferrets were extirpated using broaches without filing the canal walls. Bleeding was stimulated from the periapical tissues, and a blood clot was induced in the canal space to the level of the cementoenamel junction in 12 teeth. PRP was prepared and placed in the canals to the level of the cementoenamel junction in 9 teeth. The coronal access was sealed with mineral trioxide aggregate. Seven canines were not operated on and served as controls. Three months later, block sections including each canine and its surrounding tissues were removed for histologic evaluation. The tissues found in the canals of experimental teeth were compared with those in the control teeth.Results
Almost all of the experimental teeth showed the presence of intracanal bonelike tissue. No evidence of dentinal wall thickening or apical narrowing was noted in the experimental teeth.Conclusions
In this experimental model, the use of either PRP or blood clots during regenerative endodontics leads to the formation of intracanal bonelike tissue without continual root maturation. 相似文献84.
The role of reactive oxygen species and apoptosis in the pathogenesis of varicocele in a rat model and efficiency of vitamin E treatment 总被引:4,自引:0,他引:4
Cam K Simsek F Yuksel M Turkeri L Turker L Haklar G Yalcin S Akdas A 《International journal of andrology》2004,27(4):228-233
We investigated role of reactive oxygen species (ROS) and apoptosis in the pathogenesis of infertility in experimental model of varicocele. The protective effect of vitamin E was also examined. Three groups of rats were constructed as the first group had sham operation, experimental varicoceles were established by partial ligation of the left renal vein in later two groups. Third group had received vitamin E. Production of ROS was determined by chemiluminescence assay (CL). The in situ end labelling technique was utilized to investigate apoptosis. Tissue vitamin E levels were measured by high performance liquid chromatography. The differences between luminol enhanced CL levels of groups were not statistically significant. However, the difference between CL levels of lucigenin probe in left testicles of sham and varicocele groups were statistically significant ( p = 0.0007). Similarly, the results of the third group receiving vitamin E significantly differed from the varicocele group ( p = 0.0025). The difference of apoptotic index was also statistically significant between sham and varicocele groups ( p = 0.0038). Although the values of apoptotic index detected in the vitamin E group were lower compared with the varicocele group, the difference was not significant. This study proposes that ROS production and apoptosis in the testicles were induced with experimental varicocele. Vitamin E had a protective role. An increased rate of apoptosis with experimental varicocele suggests a molecular alteration, which may involve ROS overproduction as the triggering mechanism. Consequently, this study indicates an association between varicocele and infertility at molecular level through stimulation of ROS and apoptosis. 相似文献
85.
Total versus subtotal thyroidectomy for the management of benign multinodular goiter in an endemic region 总被引:4,自引:0,他引:4
BACKGROUND: Because controversy still continuous to surround use of total thyroidectomy for the management of benign multinodular goiter, the present study aims to prospectively compare the safety and efficacy of total thyroidectomy with subtotal thyroidectomy. METHODS: A total of 200 consecutive patients with benign multinodular goiter were assigned to have either total thyroidectomy (n = 105) or subtotal thyroidectomy (n = 95) based on preoperative evaluation, intraoperative macroscopic findings and nodular dissemination. The patients with no healthy tissue or nodules localized in the dorsal part of the gland, which are usually left during normal subtotal resection, were assigned to the total thyroidectomy group. Demographic details, biochemical findings, indications for operation, operating time, specimen weight, complications and hospital stay were noted. RESULTS: There was no significant difference in the sex, hormonal status or duration of goiter between the two groups (P = 0.74, P = 0.59 and P = 0.59, respectively). The mean operating time was longer (148.52 min +/- 51.10 vs 135.10 min +/- 32.47, P = 0.03), and the mean weight of the specimens was greater (228.40 g +/- 229.91 vs 157.01 g +/- 151.23, P = 0.01) for total rather than subtotal thyroidectomy. Either temporary recurrent laryngeal nerve (RLN) palsy or hypoparathyroidism occurred in 10 (9.3%) or 12 (11.4%) of the patients undergoing total compared with six (6.3%) or nine (9.5%) of the patients undergoing subtotal thyroidectomy (P = 0.40 and P = 0.65, respectively). Either permanent RLN palsy or hypoparathyroidism was observed in one patient undergoing total thyroidectomy (P = 0.34 for each comparison). The mean hospital stay was longer in the total thyroidectomy group (2.24 days +/- 1.18 vs 1.89 days +/- 0.72 for subtotal thyroidectomy, P = 0.01). CONCLUSIONS: The present study shows that total thyroidectomy can be performed without increasing risk of complication, and it is an acceptable alternative for benign multinodular goiter, especially in endemic regions, where patients present with a huge multinodular goiter. 相似文献
86.
Mohammad Mazloum-Ardakani Hadi Beitollahi Mohammad Kazem Amini Bibi-Fatemeh Mirjalili Fakhradin Mirkhalaf 《Journal of electroanalytical chemistry (Lausanne, Switzerland)》2011,651(2):243-249
In the present paper, the use of a gold electrode modified by 2-(2,3-dihydroxy phenyl)-1,3-dithiane self-assembled monolayer (DPDSAM) for the determination of epinephrine (EP) and uric acid (UA) was described. Initially, cyclic voltammetry was used to investigate the redox properties of this modified electrode at various scan rates. The apparent charge transfer rate constant, ks, and transfer coefficient, α, were calculated. Next, the mediated oxidation of EP at the modified electrode was described. At the optimum pH of 8.0, the oxidation of EP occurs at a potential about 155 mV less positive than that of an unmodified gold electrode. The values of electron transfer coefficients (α = 0.356), catalytic rate constant (k = 1.624 × 104 M−1 s−1) and diffusion coefficient (D = 1.04 × 10−6 cm2 s−1) were calculated for EP, using electrochemical approaches. Based on differential pulse voltammetry, the oxidation of EP exhibited a dynamic range between 0.7 and 500.0 μM and a detection limit (3σ) of 0.51 μM. Furthermore, simultaneous determination of EP and UA at the modified electrode was described. Finally, this method was used for the determination of EP in EP ampoule. 相似文献
87.
Khodamorad Jamshidi Abolfazl Bagherifard Hamadalla Hadi Al-Baseesee Alireza Mirzaei 《Clinical orthopaedics and related research》2021,479(5):1134
BackgroundHeterotopic ossification (HO) is common after total joint arthroplasty and usually does not cause diagnostic problems. However, the occurrence of HO after oncologic prostheses implantation can be troublesome as it may mimic a locally recurrent tumor. Because this distinction could have a profound impact on the surgeon and patient, it is important to distinguish the two entities; to our knowledge, no study has evaluated this after oncologic endoprosthetic reconstruction around the knee after tumor resection.Questions/purposes(1) How common is the occurrence of HO compared with local recurrence (LR) after resection of bone sarcoma and the use of an oncologic knee prosthesis? (2) Are there any factors associated with the development of HO after limb salvage procedures with an endoprosthesis? (3) What features allow the surgeon to differentiate HO from a locally recurrent tumor in this setting?MethodsBetween 2002 and 2018, we performed 409 resections of primary bone tumors followed by reconstructions with oncologic endoprostheses. Of these, 17% (71 of 409) died before 2 years and did not have HO at that time, 2% (8 of 409) were lost to follow-up before 2 years, and another 2% (10 of 409) did not have radiographs available at a minimum of 2 years after surgery (and had not developed HO before then), and so could not be analyzed, leaving 320 patients for analysis in this retrospective study. Forty-two patients were excluded; 2% (5 of 320) for a history of failed allograft reconstruction, 3% (8 of 320) for pathologic fracture at presentation, 2% (6 of 320) for inadequate or complicated biopsy, 1% (2 of 320) for stem fractures, 2% (7 of 320) for stem loosening, and 4% (14 of 320) for extracortical bone bridging, leaving 278 patients for final evaluation. Two observers analyzed AP and lateral radiographs for signs of HO at a mean follow-up of 63 ± 33 months after surgery. We defined HO as extraskeletal bone formation in soft tissues. The primary study endpoint was survivorship free from HO, as ascertained by a competing-risks estimator. To identify factors associated with HO appearance, the demographic, radiographic, clinical, pathologic, and surgical characteristics were compared between patients with HO and those who had no lesion. Characteristic features were also compared between patients with HO and those with LR to help their differentiation. Univariate analysis was used for all statistical evaluations.ResultsHO developed in 8% (21 of 278) of patients in whom oncologic knee prosthesis was implanted. LR developed in 10% (28 of 278) of the patients. According to survivorship estimates, the HO-free survival rate was not different from the LR-free survival rate at 2 years after oncologic knee reconstruction (76 ± 5% [95% CI 63 to 87] versus 74 ± 5% [95% CI 62 to 88]; p = 0.19). History of infection was more common in patients with HO than in patients with no lesion (19% [4 of 21] versus 5% [12 of 229], Odds ratio [OR] 6 [95% CI 2 to 17]; p < 0.001). The male sex was more common in the HO group as well (76% [16 of 21] versus 55% [128 of 229], OR 2 [95% CI 1 to 5]; p = 0.03). The Modular Universal Tumor and Revision System prosthesis was more frequently used in patients with HO (67% [14 of 21]) compared to those with no lesions (40% [92 of 229]; OR 2 [95% CI 1 to 5]; p = 0.02). The lesion border in radiographs was ill-defined in 19% (4 of 21) of patients with HO and 100% (28 of 28) of patients with LR (OR 8 [95% CI 3 to 20]; p < 0.001). The median time to the appearance of HO was shorter than the time to LR (8 months [3 to 13] versus 16 months [11 to 21], [95% CI 10 to 13]; p < 0.001). Pain at presentation was more frequent in patients with LR than in those with HO (86% [24 of 28] versus 14% [3 of 21], OR 36 [95% CI 7 to 181]; p < 0.001).ConclusionHO may occur after the use of oncologic knee prostheses for reconstruction after tumor resection. In most patients, HO could be differentiated from local recurrence through identifying a well-defined border on radiographs. Otherwise, factors such as an earlier time of presentation and absence of pain could suggest an HO, rather than an LR.Level of EvidenceLevel III, therapeutic study. 相似文献
88.
Lauren SY Wood Hadi S Hosseini Modupeola Diyaolu Anne-Laure Thomas Jordan S Taylor James CY Dunn 《Journal of pediatric surgery》2021,56(7):1192-1198
Introductionshort bowel syndrome is marked by inadequate intestinal surface area to absorb nutrients. Current treatments are focused on medical management and surgical reconfiguration of the dilated intestine. We propose the use of spring-mediated distraction enterogenesis as a novel intervention to increase intestinal length. Given our previous success lengthening intestinal segments using springs with spring constant ~7 N/m that exerts 0.46 N or higher, we sought to determine the minimal force needed to lengthen porcine small intestinal segments, and to explore effects on intestine over time.MethodsJuvenile Yucatan pigs underwent laparotomy with enterotomy to introduce nitinol springs intraluminally (n = 21 springs). Bowel segments (control, spring-distracted) were retrieved on post-operative day (POD) 7 and 14, and lengths measured. Thickness of cross-sectional intestinal layers were measured using H&E, and submucosal collagen fiber orientation measured using trichrome stained sections.Resultsall pigs survived to POD7 and 14. Spring constants of at least 2 N/m exerting a minimum force of 0.10 N significantly lengthened intestinal segments (p <0.0001). The stronger the spring force, the greater the induced thickness of various intestinal layers at POD7 and 14. Collagen fiber orientation was also more disordered because of stronger springs.Conclusiona spring constant of approximately 2 N/m exerting 0.10 N and greater significantly lengthens intestinal segments and stimulates intestinal structural changes at POD7 and 14. This suggests a decreased force is capable of inducing spring-mediated distraction enterogenesis. 相似文献
89.
Hadi Tabibi Atefeh As’habi Mitra Mahdavi-Mazdeh Mehdi Hedayati Behnaz Nozary-Heshmati 《International urology and nephrology》2014,46(10):2015-2020