全文获取类型
收费全文 | 742篇 |
免费 | 48篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 23篇 |
妇产科学 | 10篇 |
基础医学 | 66篇 |
口腔科学 | 16篇 |
临床医学 | 56篇 |
内科学 | 147篇 |
皮肤病学 | 21篇 |
神经病学 | 9篇 |
特种医学 | 63篇 |
外科学 | 207篇 |
综合类 | 6篇 |
预防医学 | 43篇 |
眼科学 | 37篇 |
药学 | 38篇 |
中国医学 | 1篇 |
肿瘤学 | 41篇 |
出版年
2023年 | 17篇 |
2022年 | 33篇 |
2021年 | 47篇 |
2020年 | 16篇 |
2019年 | 29篇 |
2018年 | 67篇 |
2017年 | 36篇 |
2016年 | 28篇 |
2015年 | 27篇 |
2014年 | 39篇 |
2013年 | 46篇 |
2012年 | 84篇 |
2011年 | 68篇 |
2010年 | 35篇 |
2009年 | 18篇 |
2008年 | 30篇 |
2007年 | 37篇 |
2006年 | 28篇 |
2005年 | 34篇 |
2004年 | 24篇 |
2003年 | 22篇 |
2002年 | 18篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有796条查询结果,搜索用时 15 毫秒
41.
OBJECTIVE: To conduct a meta-analysis of randomized controlled studies to evaluate abdominal ultrasound-guided embryo transfer compared to the clinical touch method. DESIGN: Meta-analysis. SETTING: Four studies performed in academic research centers in Barcelona, Vizcaya, Hong Kong, and Madrid. PATIENT(S): A total of 2,051 patients: 1,024 received ultrasound-guided embryo transfers and 1,027 received clinical touch method transfers. INTERVENTION(S): Fourteen studies were retrieved from the literature, but only four of them fitted our selection criteria. The meta-analysis was conducted using the RevMan software with the Peto-modified Mantel-Haenszel method and the fixed effect model. MAIN OUTCOME MEASURE(S): The primary outcome measures were the clinical pregnancy and ongoing pregnancy rates. The secondary outcome measures were the incidences of ectopic pregnancies, miscarriage rate, multiple pregnancies, and difficult transfers. RESULT(S): Compared to the clinical touch method, abdominal ultrasound-guided transfer significantly increased the clinical pregnancy rate and the ongoing pregnancy rate. There was no effect on the incidence of ectopic pregnancy, multiple pregnancy, or miscarriage rate. CONCLSUION(S): Ultrasound-guided embryo transfer increases the clinical pregnancy and ongoing pregnancy rates significantly compared to the clinical touch method. 相似文献
42.
OBJECTIVE: To assess the relative genetic and environmental contribution to carpal tunnel syndrome (CTS) using a classic twin study of monozygotic (MZ) and dizygotic (DZ) twins.METHODS:The study group comprised unselected female twin pairs, between 20 and 80 years of age, from the St Thomas' UK Adult Twin Registry. Individuals completed a questionnaire that included details on potential risk factors for CTS. The diagnosis of CTS was made using a standardized hand pain diagram and validated criteria. The genetic contribution to CTS was assessed using variance component and regression methods, the heritability was adjusted for environmental confounders. The role of individual risk factors was assessed by a nested case-control study.RESULTS: An overall prevalence of 14.2% for CTS was found in a population of 4,488 females, comprising 867 MZ and 970 DZ twin pairs, and 814 singletons. The concordance for CTS was significantly higher in MZ compared with DZ twins (case-wise concordance values of 0.35 and 0.24 respectively, with a significantly increased MZ:DZ ratio of 1.48; P = 0.03). Modeling produced a heritability estimate of 0.46 (95% CI 0.34-0.58) that was essentially unchanged after adjustment for environmental risk factors including age, body mass index, physical activities, and hormonal/reproductive factors. No major influence of any individual risk factor was seen in the case-control analysis of 520 cases and 3,154 controls, apart from a modest association with menopausal status with an increased risk of 1.53 and 1.43 in the peri and postmenopausal groups. There was no overall effect of age or body mass index.CONCLUSION: This is the first study to explore the genetic component of CTS. Our data show that up to half of the liability to CTS in women is genetically determined, and this appears to be the single strongest risk factor, with only minor contributions from known environmental factors. Further studies should focus on genetic mechanisms that may lead to tests for susceptibility and detection of those at risk of developing CTS. 相似文献
43.
Late adverse reactions to intravascular iodinated contrast media 总被引:1,自引:0,他引:1
Webb JA Stacul F Thomsen HS Morcos SK;Members Of The Contrast Media Safety Committee Of The European Society Of Urogenital Radiology 《European radiology》2003,13(1):181-184
Late adverse reactions to intravascular iodinated contrast media are defined as reactions occurring 1 h to 1 week after contrast
medium injection. They have received increasing interest over the past decade, but their prevalence remains uncertain and
their pathophysiology is not fully understood. The Contrast Media Safety Committee of the European Society of Urogenital Radiology
decided to review the literature and to issue guidelines. An extensive literature search was carried out and summarized in
a report. Based on the available information, simple guidelines have been drawn up. The report and guidelines were discussed
at the 8th European Symposium on Urogenital Radiology in Genoa. Late adverse reactions after intravascular iodinated contrast
medium include symptoms such as nausea, vomiting, headache, itching, skin rash, musculoskeletal pain, and fever. A significant
proportion of these reactions is unrelated to the contrast medium; however, allergy-like skin reactions are well-documented
side effects of contrast media with an incidence of approximately 2%. Late reactions appear to be commoner after non-ionic
dimers. The majority of late skin reactions after contrast medium exposure are probably T-cell-mediated allergic reactions.
Patients at increased risk of late skin reactions are those with a history of previous contrast medium reaction and those
on interleukin-2 treatment. Most skin reactions are self-limiting and resolve within a week. Management is symptomatic and
similar to the management of other drug-induced skin reactions.
Electronic Publication 相似文献
44.
Torella F de Cossart L Dimitri SK Edwards PR 《Cardiovascular surgery (London, England)》2003,11(6):459-463
We have evaluated the safety and efficacy of routine beta-blockade for the prevention of cardiac complications in a comprehensive series of patients undergoing major vascular surgery and amputation for atherosclerotic arterial disease. From 1 December 2001 to 31 May 2002, patients received perioperative beta-blockade by atenolol. Outcomes in this period were compared to the immediately antecedent 6 months. The main outcome measure was the occurrence of cardiac complications. Fifty-three patients underwent surgery in the first period and 54 in the second. After introduction of routine beta-blockade, only one patient suffered cardiac complications compared to 10 in the first period (P=0.01). There were eight deaths in the first and two in the second period (P=0.052). On multivariate analysis, treatment with beta-blockers was the only variable significantly associated with a decrease in cardiac morbidity (OR=0.12; 95% CI=0.002-0.66; P=0.014). Two patients suffered bronchospasm leading to discontinuation of atenolol. Routine perioperative beta-blockade was safe and reduced the occurrence of cardiac complications after vascular surgery. 相似文献
45.
Sameh IS Gewaeli NN Hamza UA Awadalla MM 《Interactive Cardiovascular and Thoracic Surgery》2003,2(3):364-366
A 33-year-old female had a left sided chest pain for the last 3 months. Chest X-ray showed a left basal opacity. Computed tomography chest suggested a left sided subpulmonic effusion (17.5x12.2x13 cm) with thick enhanced walls with marked collapse of the left lower lobe and displacement of the heart and mediastinum to the right side. Trial of thoracocentesis was done and it was positive. Trial of intercostal tube insertion was done with a sense of very thick pleura and the patient developed a vasovagal attack. Accordingly, exploratory thoracotomy was decided. Intraoperative assessment showed a huge anterosuperior mediastinal cyst attached to the pericardium and was successfully resected. The pathological findings were compatible with epidermoid cyst. 相似文献
46.
47.
Gamal Esmat Aisha Elsharkawy Wafaa El Akel Ahmed Fouad Karem Helal Mostafa Kamal Mohamed Dina Attia Hany Khattab Wahid Doss Sameh Labib 《Arab Journal Of Gastroenterology》2013,14(3):109-112
Background and study aimsBoth hepatitis C virus (HCV) and schistosomiasis are highly endemic in Egypt and coinfection is frequently encountered. Such coinfection is responsible for leading to a more severe liver disease. Hence, the aim of the study was to assess the fibroscan in chronic HCV patients coinfected with Schistosoma.Patients and methodsThis study included 231 chronic HCV patients. Routine pre-treatment work-up was done including anti-schistosomal antibodies. Liver stiffness measurements using fibroscan and reference needle-liver biopsy were done. Patients were categorised into two groups: HCV patients with positive schistosomal serology and HCV patients with negative schistosomal serology.ResultsAnti-schistosomal antibody was positive in 29% of the studied population. Positive schistosomal serology status was significantly associated with the disagreement between the results of liver biopsy (Metavir) and the fibroscan results (p value = 0.02), which was more obvious in F2 and F3 fibrosis stages. The sensitivity of fibroscan for the detection of the F2 stage decreased from 64% among negative schistosomal serology patients to 30.8% among positive schistosomal serology patients, and for the F3 stage it decreased from 43.8% to 21.4%, respectively. Multivariate logistic regression showed that fibrosis stages (F0–F1 and F4) were the most independent factors that were associated with the agreement between fibroscan and liver biopsy (odds ratio (OR) 3.4, 7.12 and p value <0.001, <0.001, respectively).ConclusionAlthough the sensitivity of fibroscan for the detection of fibrosis stages (F2 and F3) was impaired in patients with positive schistosomal serology, fibrosis stages (F0–F1 and F4) were the most independent factors associated with the agreement between fibroscan and liver biopsy. 相似文献
48.
Sameh Abdelkhalik Ahmed Mohamad Gamal Elmawy Mohammed Awd 《Egyptian Journal of Anaesthesia》2018,34(1):21-25
Background
The use of an adjuvant to local anesthetics in the peribulbar block may improve the block characteristics. This study aimed to evaluate the effect of the addition of either ketamine or fentanyl to local anesthetics in single injection peribulbar block on the quality of the block.Methods
The study included ninety adult patients presented for vitreoretinal surgeries. Patients were randomly allocated into three groups. All patients received peribulbar block with a local anesthetic mixture composed of 4?ml lidocaine 2% containing hyaluronidase, and 5?ml of plain bupivacaine 0.5% with an addition of either 1?ml of normal saline, 30?μg fentanyl, or 25?mg ketamine in Control group, Fentanyl group, and Ketamine group respectively. The measurements included the onset and duration of both anesthesia and akinesia with evaluation of intraocular pressure, postoperative pain score and need of analgesics.Results
As compared to control group, the use of either fentanyl or ketamine as local anesthetic adjuvant significantly fastened the onset of anesthesia (1.67?±?1.21?min) (1.93?±?1.36?min), prolonged the duration of lid akinesia (127.50?±?22.20?min) (127.00?±?22.19?min), increased the duration of globe akinesia (156.00?±?28.02?min) (158.00?±?31.18?min), minimized the time required to start surgery (6.57?±?1.99?min) (6.57?±?1.85?min), and increased the time for first request of postoperative analgesia (189.50?±?34.92?min) (184.67?±?35.37?min) (P?<?.05). However, neither fentanyl nor ketamine had a significant effect on the onset of lid or globe akinesia or the intraocular pressure (P?>?.05).Conclusion
Fentanyl or ketamine can be used as a local anesthetic adjuvant in the peribulbar block in patients presented for vitreoretinal surgeries as both of them improved the quality of the block without increasing intraocular pressure. 相似文献49.
Souhir Chaabane Meriam Messedi Rim Akrout Mariem Ben Hamad Mouna Turki Sameh Marzouk Leila Keskes Zouheir Bahloul Ahmed Rebai Fatma Ayedi Abdellatif Maalej 《Inflammation research》2018,67(8):703-710
Objectives
The study investigated the association between plasma homocysteine, folate and vitamin B12 with 5,10 methylenetetrahydrofolate reductase (MTHFR C677T and A1298C), thymidylate synthase (TYMS 2R → 3R) and methionine synthase (MTR A2756G) polymorphisms and methotrexate (MTX) treatment and toxicity in Tunisian Rheumatoid arthritis (RA) patients.Methods
A total of 185 patients with RA were included. Homocysteine (Hcy) was assessed by fluorescence polarization immunoassay, and folate and vitamin B12 were measured by chemiluminescence immunoassays. The genetic polymorphisms were analyzed by PCR or PCR-RFLP. Hyperhomocysteinemia (HHC) was considered for Hcy?>?15 µmol/L.Results
MTHFR C677T polymorphism was associated with HHC in RA patients (multi-adjusted OR, 95% CI 2.18, [1.07–4.57]; p?=?0.031). No association was detected with the remaining polymorphisms. Plasma Hcy, folate, and vitamin B12 did not differ according to each polymorphism, or with MTX treatment or toxicity. However, HHC was more prevalent in patients with than those without MTX toxicity (32.7 vs. 16.7%; p?=?0.035).Conclusions
The MTHFR 677TT genotype is an independent risk factor for HHC in Tunisians RA patients. HHC could be a useful marker of MTX toxicity in RA patients.50.
Michael M. Shenouda Shady ElGhazaly Harb Sameh A. A. Mikhail Sherif M. Mokhtar Ayman M. A. Osman Arsany T. S. Wassef Nayer N. H. Rizkallah Nader M. Milad Shady E. Anis Tamer Mohamed Nabil Nader Sh. Zaki Antoine Halepian 《Obesity surgery》2018,28(2):389-395