全文获取类型
收费全文 | 13652篇 |
免费 | 799篇 |
国内免费 | 96篇 |
专业分类
耳鼻咽喉 | 153篇 |
儿科学 | 342篇 |
妇产科学 | 405篇 |
基础医学 | 1600篇 |
口腔科学 | 395篇 |
临床医学 | 1108篇 |
内科学 | 3044篇 |
皮肤病学 | 292篇 |
神经病学 | 529篇 |
特种医学 | 489篇 |
外国民族医学 | 5篇 |
外科学 | 2188篇 |
综合类 | 384篇 |
一般理论 | 9篇 |
预防医学 | 991篇 |
眼科学 | 422篇 |
药学 | 1252篇 |
中国医学 | 119篇 |
肿瘤学 | 820篇 |
出版年
2023年 | 170篇 |
2022年 | 469篇 |
2021年 | 664篇 |
2020年 | 402篇 |
2019年 | 530篇 |
2018年 | 581篇 |
2017年 | 403篇 |
2016年 | 416篇 |
2015年 | 411篇 |
2014年 | 596篇 |
2013年 | 730篇 |
2012年 | 1020篇 |
2011年 | 1086篇 |
2010年 | 638篇 |
2009年 | 507篇 |
2008年 | 773篇 |
2007年 | 784篇 |
2006年 | 653篇 |
2005年 | 589篇 |
2004年 | 515篇 |
2003年 | 462篇 |
2002年 | 397篇 |
2001年 | 170篇 |
2000年 | 158篇 |
1999年 | 160篇 |
1998年 | 74篇 |
1997年 | 46篇 |
1996年 | 58篇 |
1995年 | 52篇 |
1994年 | 51篇 |
1993年 | 34篇 |
1992年 | 75篇 |
1991年 | 69篇 |
1990年 | 83篇 |
1989年 | 65篇 |
1988年 | 69篇 |
1987年 | 65篇 |
1986年 | 64篇 |
1985年 | 46篇 |
1984年 | 44篇 |
1983年 | 24篇 |
1982年 | 24篇 |
1980年 | 25篇 |
1979年 | 31篇 |
1977年 | 27篇 |
1976年 | 30篇 |
1974年 | 16篇 |
1973年 | 20篇 |
1970年 | 19篇 |
1969年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 25 毫秒
91.
Abeer Ahmed Rushdy Mona Ibrahim Mabrouk Ferialla Abdel-Hamid Abu-Sef Zeinab Hassan Kheiralla Said Mohamed Abdel -All Neveen Mohamed Saleh 《The Brazilian journal of infectious diseases》2013,17(4):431-437
ObjectivesTo study the potential factors include gene mutation, efflux pump and alteration of permeability associated with quinolone-resistance of Salmonella enterica strains isolated from patients with acute gastroenteritis and to evaluate the degree of synergistic activity of efflux pump inhibitors when combined with ciprofloxacin against resistant isolates.MethodsAntimicrobial resistance patterns of fifty-eight Salmonella isolates were tested. Five isolates were selected to study the mechanism of resistance associated with quinolone group, including mutation in topoisomerase-encoding gene, altered cell permeability, and expression of an active efflux system. In addition, the combination between antibiotics and efflux pump inhibitors to overcome the microbial resistance was evaluated.ResultsFive Salmonella isolates totally resistant to all quinolones were studied. All isolates showed alterations in outer membrane proteins including disappearance of some or all of these proteins (Omp-A, Omp-C, Omp-D and Omp-F). Minimum inhibitory concentration values of ciprofloxacin were determined in the presence/absence of the efflux pump inhibitors: carbonyl cyanide m-chlorophenylhydrazone, norepinephrin and trimethoprim. Minimum inhibitory concentration values for two of the isolates were 2–4 fold lower with the addition of efflux pump inhibitors. All five Salmonella isolates were amplified for gyrA and parC genes and only two isolates were sequenced. S. Enteritidis 22 had double mutations at codon 83 and 87 in addition to three mutations at parC at codons 67, 76 and 80 whereas S. Typhimurium 57 had three mutations at codons 83, 87 and 119, but no mutations at parC.ConclusionsEfflux pump inhibitors may inhibit the major AcrAB-TolC in Salmonella efflux systems which are the major efflux pumps responsible for multidrug resistance in Gram-negative clinical isolates. 相似文献
92.
93.
94.
Ahmed Mousa Altaf A. Kondkar Saleh A. Al-Obeidan Taif A. Azad Tahira Sultan Essam Osman Khaled K. Abu-Amero 《Saudi medical journal》2015,36(6):671-677
Objectives:
To compare the mean total antioxidant status (TAS) among 3 glaucoma types, namely: pseudoexfoliation glaucoma (PEG), primary open angle glaucoma (POAG), and primary angle closure glaucoma (PACG), and study its potential association with various clinical glaucoma-parameters.Methods:
In this case-control study, plasma samples were obtained between September 2013 and October 2014 from 340 glaucoma patients (PEG [n=54]; POAG [n=147]; PACG [n=139]), and 351 controls of matching age, gender, ethnicity, and 5 different systemic co-morbidities from King Abdulaziz University Hospital, Riyadh, Saudi Arabia. The TAS in all samples was determined by a colorimetric-based assay.Results:
The mean±standard deviation of TAS was significantly lower among cases: 0.77±0.32 than controls: 1.1±0.22, p<0.0001. Moreover, the TAS levels were significantly different across the 3 types of glaucoma: 0.86±0.24 in PEG, 0.47±0.32 in POAG, and 0.98±0.41 in PACG (all p<0.0001). In addition, there was a significant correlation between TAS and age at onset (Pearson correlation coefficient [R] 0.17, p<0.0001), cup/disc ratio (R: -0.13, p=0.004), and number of anti-glaucoma medications (R: -0.16, p=0.001).Conclusion:
Our findings provide evidence that plasma TAS levels are decreased in patients with glaucoma, more so in POAG and PEG than PACG, supporting the hypothesis that decreased antioxidative defense and/or increased oxidative stress may have a critical role in the pathogenesis of glaucoma.Glaucoma is a progressive optic neuropathy associated with optic nerve damage, and is one of the most leading cause of blindness worldwide.1 Elevated intraocular pressure (IOP) as a result of reduction in normal aqueous outflow is a major causal risk factor that is well supported by animal studies.2-4 Although IOP is considered a major risk factor for glaucoma,2,3 other concomitant factors affecting the pathophysiology of glaucomatous retinal ganglion cell (RGC) death include retinal ischemia,5 nutritional status,6 and oxidative stress.7 There is evidence of oxidative damage in ocular diseases, such as cataract and age-related macular degeneration.8 In addition, significant oxidative damage has been demonstrated in human trabecular meshwork (TM) cells of patients with glaucoma,7 causing elevated IOP and visual field damage.9 Furthermore, our previous studies have documented mitochondrial abnormalities10-12 (oxidative stress marker), and glutathione-S-transferase (antioxidant) gene (GST) polymorphisms to be associated with various types of glaucoma.13 It is clearly evident from the literature, and our own studies, that oxidative stress mechanisms play a critical role in the pathogenesis of glaucoma. Previous studies had demonstrated reduced total antioxidant capacity in aqueous humor and blood samples from patients with glaucoma.14-17 To evaluate the role of oxidative stress in different types of glaucoma we had previously investigated total antioxidants status (TAS) in the plasma of pseudoexfoliation glaucoma (PEG) patients,18 primary angle closure glaucoma (PACG) patients,19 and in the plasma of primary open angle glaucoma (POAG) patients.20 As an extension to these studies, here, we compare the mean TAS level among these 3 glaucoma types, and study the potential association between the TAS level and various clinical parameters important to each type of glaucoma.18-20 相似文献95.
St Rammos K Koullias GJ Hassan MO Argyrakis NP Voucharas CG Scarupa SJ Cowte TG 《Cardiovascular surgery (London, England)》2002,10(3):228-232
PURPOSE OF THE STUDY: Atrial fibrillation after cardiac surgery is still a frequent encountered complication and has been associated with increased hospital length of stay and numerous postoperative complications. The pathogenesis of atrial fibrillation involves an overall sequence of perioperative events, collectively termed as ischemia-reperfusion injury. Heat-shock proteins have been found to provide increased protection during ischemia-reperfusion as well as increased postischemic cardiac functional recovery. We sought to determine whether preoperative atrial heat shock levels were correlated with the appearance of postoperative atrial fibrillation. BASIC METHODS: Preoperative atrial myocardial samples obtained just before cannulation from 101 patients were used to detect immunohistochemically the expression of heat-shock proteins. The derived results were compared statistically with the incidence of postoperative atrial fibrillation, its time of appearance, duration and resistance to administered antiarrhythmics. PRINCIPAL FINDINGS: The overall incidence of postoperative atrial fibrillation was 22.3%. Of these patients, 58.3% had no detectable heat shock proteins in their cytoplasm, in sharp contrast with 100% of the patients with no atrial fibrillation who were positive for heat shock proteins (p<0.01). Four percent of our patient group had prolonged atrial fibrillation (defined as duration >48 h). These patients had significantly less (p<0.01) nuclear heat shock protein expression compared with the non-atrial fibrillation group. However, the difference of the heat shock protein expression between the prolonged atrial fibrillation and the rest of the atrial fibrillation patients was not significant (p=0.891). CONCLUSIONS: Our results indicate that patients with low preoperative atrial heat shock protein expression have a significantly greater incidence of postoperative atrial fibrillation. Heat shock protein expression did not, however, correlate with the onset of atrial fibrillation and the resistance to administered medications. Heat shock protein preoperative induction as a measure of myocardial preconditioning may potentially decrease the incidence of postoperative atrial fibrillation. 相似文献
96.
Yip CH Cazap E Anderson BO Bright KL Caleffi M Cardoso F Elzawawy AM Harford JB Krygier GD Masood S Murillo R Muse IM Otero IV Passman LJ Santini LA da Silva RC Thomas DB Torres S Zheng Y Khaled HM 《Breast (Edinburgh, Scotland)》2011,20(Z2):S12-S19
In middle resource countries (MRCs), cancer control programs are becoming a priority as the pattern of disease shifts from infectious diseases to non-communicable diseases such as breast cancer, the most common cancer among women in MRCs. The Middle Resource Scenarios Working Group of the BHGI 2010 Global Summit met to identify common issues and obstacles to breast cancer detection, diagnosis and treatment in MRCs. They concluded that breast cancer early detection programs continue to be important, should include clinical breast examination (CBE) with or without mammography, and should be coupled with active awareness programs. Mammographic screening is usually opportunistic and early detection programs are often hampered by logistical and financial problems, as well as socio-cultural barriers, despite improved public educational efforts. Although multidisciplinary services for treatment are available, geographical and economic limitations to these services can lead to an inequity in health care access. Without adequate health insurance coverage, limited personal finances can be a significant barrier to care for many patients. Despite the improved availability of services (surgery, pathology, radiology and radiotherapy), quality assurance programs remain a challenge. Better access to anticancer drugs is needed to improve outcomes, as are rehabilitation programs for survivors. Focused and sustained government health care financing in MRCs is needed to improve early detection and treatment of breast cancer. 相似文献
97.
Elsherbiny OE Salem MA El-Sabbagh AH Elhadidy MR Eldeen SM 《Burns : journal of the International Society for Burn Injuries》2011,37(5):776-789
Background
Burns are one of the most significant health problems throughout the world, leading to prolonged hospitalisation and hence increased expense for the patients, their families and society. Today, the prognosis of patients with burns is dependent, apart from adequate treatment, upon the health-care system and health-care professionals, regarding not only survival, but also lifelong quality of life. This study aims to assess quality of life of adult patients with severe burns.Patients and methods
This study was conducted on 100 adult patients with severe burns in the burn outpatient clinic (male and female) at Mansoura University Hospital. Parameters of burn and Burn Specific Health Scale (BSHS-B) were used to assess quality of life following burns.Results
The study revealed that burns has negative impact on most dimensions of the quality of life of patients with burns.Conclusions
The quality of life for people who have sustained a burns should be recognised and valued by the burn team in all phases of burn care. 相似文献98.
Hassan Sadri Richard Stern Michael Singh Berend Linke Pierre Hoffmeyer Karsten Schwieger 《Archives of orthopaedic and trauma surgery》2011,131(1):131-138
Introduction
The gold standard for treating transverse olecranon fractures is tension band fixation. A problem with this technique is migration of the K-wires leading to premature hardware removal. The aim of this study is to compare stability provided by two new techniques designed to eliminate the problem with backing out of K-wires, with that of the recommended tension band technique, performed with a biomechanical in vitro investigation. Our hypothesis was that the two new techniques would provide at least equal stability as the traditional tension band fixation. 相似文献99.
Rodriguez MA Cass DL Lazar DA Cassady CI Moise KJ Johnson A Mushin OP Hassan SF Belleza-Bascon B Olutoye OO 《Journal of pediatric surgery》2011,46(6):1182-1185
Purpose
This study was designed to develop a prognostic factor for fetuses with sacrococcygeal teratoma (SCT) that may be useful to predict outcome and guide counseling early in pregnancy. We hypothesize that, in fetuses with SCT, the ratio of tumor size to estimated fetal weight in the second trimester predicts outcome.Methods
We retrospectively reviewed charts of all patients evaluated at our Fetal Center for SCT between 2004 and 2009. Estimated fetal weight and tumor volume were calculated based on prenatal ultrasound or fetal magnetic resonance imaging. Patients were stratified based on tumor volume to fetal weight ratio (TFR), and their outcomes were analyzed by Fisher's Exact test.Results
Tumor volume to fetal weight ratio before 24 weeks' gestation was predictive of outcome. Those with a TFR less than or equal to 0.12 (n = 5) had a significantly better outcome than patients with a TFR greater than 0.12 (n = 5, P < .05). All patients with poor outcomes had a TFR greater than 0.12 by 24 weeks' gestation. A TFR greater than 0.12 predicted poor outcome with 100% sensitivity and 83% specificity. All 4 patients who developed hydrops had a TFR greater than 0.12.Conclusion
In our series of fetuses with SCT, TFR before 24 weeks' gestation correlates with outcome. This novel, prenatal diagnostic tool may be useful in prenatal counseling and for early identification of high-risk fetuses. 相似文献100.
El-Sabbagh AH 《Journal of reconstructive microsurgery》2011,27(9):511-523
The local fasciocutaneous flap has the advantage of low donor site morbidity when used for the coverage of lower limb defects. However, flap reliability remains a major problem with its use. Perforator flaps are indicated for several clinical problems. The versatility of the perforator flap makes it ideal for the reconstruction of extremities. Between September 2007 and November 2010, 34 skin perforator flaps were raised in 33 cases. Flaps which were executed as peroneal artery flaps were 13, 0.16 flaps were raised as posterior tibial artery perforator flaps, and 5 flaps as medial sural medial gastrocnemius muscle perforator skin flap. A segmental perforator was dissected and retained. Thirty-two flaps survived completely and none exhibited venous compromise. In one patient, flap was lost completely and the other showed partial tip necrosis. Complicated flaps were responded to conservative treatment. Skin perforator flap represents a technical advancement over conventional lower limb skin flaps because of its improved vascularity. It provides the surgeon with additional reconstructive options in reconstruction of difficult areas and injuries of leg. Clinical judgment is essential to assess the potential vascular territory of the flap. 相似文献