全文获取类型
收费全文 | 4195篇 |
免费 | 410篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 142篇 |
妇产科学 | 187篇 |
基础医学 | 474篇 |
口腔科学 | 137篇 |
临床医学 | 312篇 |
内科学 | 885篇 |
皮肤病学 | 232篇 |
神经病学 | 192篇 |
特种医学 | 220篇 |
外国民族医学 | 8篇 |
外科学 | 590篇 |
综合类 | 90篇 |
预防医学 | 270篇 |
眼科学 | 68篇 |
药学 | 472篇 |
中国医学 | 21篇 |
肿瘤学 | 290篇 |
出版年
2023年 | 51篇 |
2022年 | 150篇 |
2021年 | 228篇 |
2020年 | 159篇 |
2019年 | 239篇 |
2018年 | 262篇 |
2017年 | 205篇 |
2016年 | 195篇 |
2015年 | 215篇 |
2014年 | 226篇 |
2013年 | 292篇 |
2012年 | 322篇 |
2011年 | 312篇 |
2010年 | 209篇 |
2009年 | 166篇 |
2008年 | 149篇 |
2007年 | 160篇 |
2006年 | 150篇 |
2005年 | 143篇 |
2004年 | 111篇 |
2003年 | 99篇 |
2002年 | 98篇 |
2001年 | 18篇 |
2000年 | 17篇 |
1999年 | 27篇 |
1998年 | 17篇 |
1997年 | 20篇 |
1996年 | 19篇 |
1995年 | 14篇 |
1994年 | 11篇 |
1993年 | 12篇 |
1992年 | 30篇 |
1991年 | 14篇 |
1990年 | 18篇 |
1988年 | 21篇 |
1987年 | 20篇 |
1986年 | 14篇 |
1985年 | 22篇 |
1984年 | 11篇 |
1982年 | 11篇 |
1980年 | 11篇 |
1979年 | 16篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 10篇 |
1971年 | 11篇 |
1970年 | 10篇 |
1969年 | 9篇 |
1968年 | 7篇 |
1967年 | 12篇 |
排序方式: 共有4634条查询结果,搜索用时 14 毫秒
41.
Rebecca L. Johnson Matthew P. Abdel Ryan D. Frank Alanna M. Chamberlain Elizabeth B. Habermann Carlos B. Mantilla 《The Journal of arthroplasty》2019,34(1):56-64.e5
Background
Frailty and disability from arthritis are closely intertwined and little is known about the impact of frailty on total hip arthroplasty (THA) outcomes. We hypothesized that higher preoperative frailty is associated with more adverse events following THA.Methods
All patients (≥50 years) undergoing unilateral primary or revision THA at a single institution from 2005 through 2016 were included. We analyzed the association of frailty (measured by a frailty deficit index) with postoperative outcomes in hospital, within 90 days, and within 1 year using multivariable logistic and Cox regression, adjusting for age.Results
Among 8640 patients undergoing THA (6502 primary and 2138 revisions; median age 68 years), 22.7%, 32.9%, and 44.4% were classified as frail, vulnerable, and nonfrail, respectively. Frail patients tended to be female, older, sicker (American Society of Anesthesiologists ≥3), and received general anesthesia more frequently. Relative to nonfrail patients, frail patients had significantly increased odds of wound complications/hematoma (odds ratio 2.01) and reoperation (odds ratio 2.74) while in hospital, and increased risks for mortality (1-year hazards ratio [HR] 5.65), infection (1-year HR 3.63), dislocation (1-year HR 2.10), wound complications/hematoma (1-year HR 2.61), and reoperation (1-year HR 2.22) within 90 days and 1 year. Frailty was also associated with >5.5-fold increased mortality risk 1 year following THA. No significant associations with aseptic loosening, periprosthetic fracture, or heterotopic ossification were observed.Conclusion
A higher preoperative frailty index is associated with increased mortality and perioperative complications following primary and revision THA. The proposed frailty deficit index provides clinically important information for healthcare providers to use when counseling patients prior to decision for surgery. 相似文献42.
Florian Stengel Andrew J. Baldwin Alexander J. Painter Nomalie Jaya Eman Basha Lewis E. Kay Elizabeth Vierling Carol V. Robinson Justin L. P. Benesch 《Proceedings of the National Academy of Sciences of the United States of America》2010,107(5):2007-2012
Small Heat Shock Proteins (sHSPs) are a diverse family of molecular chaperones that prevent protein aggregation by binding clients destabilized during cellular stress. Here we probe the architecture and dynamics of complexes formed between an oligomeric sHSP and client by employing unique mass spectrometry strategies. We observe over 300 different stoichiometries of interaction, demonstrating that an ensemble of structures underlies the protection these chaperones confer to unfolding clients. This astonishing heterogeneity not only makes the system quite distinct in behavior to ATP-dependent chaperones, but also renders it intractable by conventional structural biology approaches. We find that thermally regulated quaternary dynamics of the sHSP establish and maintain the plasticity of the system. This extends the paradigm that intrinsic dynamics are crucial to protein function to include equilibrium fluctuations in quaternary structure, and suggests they are integral to the sHSPs’ role in the cellular protein homeostasis network. 相似文献
43.
Objectives
To evaluate the safety of using the stiff end of a coronary wire to perforate an atretic pulmonary valve (PV) in patients with pulmonary atresia with intact ventricular septum (PAIVS).Background
Radiofrequency perforation is an accepted modality to perforate the PV in patients PAIVS. However, the high cost precludes its widespread use.Patients and methods
This is a single-center experience that spanned from March 2013 to January 2016 and involved 13 neonates who were severely cyanotic with PAIVS and with ductal-dependent pulmonary circulation. The stiff end of a coronary wire was used to perforate the atretic PV anterogradely, followed by balloon pulmonary valvuloplasty.Results
The mean age of patients was 3.9?±?2.7?days and their mean weight was 2.8?±?0.19?kg. The mean oxygen saturation was 77.1?±?3.2%. All had membranous pulmonary atresia, with patent infundibulum and tripartite right ventricle. The valve was successfully perforated in 11 out of 13 patients. Death occurred in two patients (15.4%) owing to heart failure and sepsis. Patent ductus arteriosus stenting was performed 2?days after the procedure in one patient because of cyanosis followed by one and half ventricle repair at of age 5?months. Two patients (15.4%) had one and a half ventricle repair at age of 5?months and 6?months owing to insufficient anterograde pulmonary flow. Two patients (15.4%) underwent second intervention with balloon dilatation of the valve. The remaining seven patients (53.8%) had no further intervention. Two cases (15.4%) had femoral artery thrombosis treated with streptokinase. The mean duration of follow-up was 13.17?±?7?months. There was significant improvement in the degree of tricuspid incompetence. There was a significant growth in the tricuspid valve annulus during the follow-up (the mean Z score increased from ?0.8?±?0.9 to 0.1?±?0.9) (p?=?0.003). There was also a significant increase in the tricuspid valve annulus/mitral valve annulus ratio as its mean increased from 0.73?±?0.10 to 0.86?±?0.11 during follow-up (p?<?0.001).Conclusion
Perforation of the atretic PV in selected cases with membranous atresia and patent infundibulum using the stiff end of a coronary wire is an effective alternative to using radiofrequency perforation. 相似文献44.
Nihal Fathi Samar H. Goma Nadia M. Ismail Abeer M. Ghandour Sally S. Youssef Nisreen A. Mohammed Eman Mosad 《The Egyptian Rheumatologist》2018,40(1):45-49
Background
Systemic sclerosis (SSc) is an autoimmune connective tissue disease with vascular, fibrotic and immune changes of skin and some internal organs. Anti-heterogeneous nuclear ribonucleoproteins (anti-hnRNP) were found in SSc patients.Aim of the work
To assess anti-hnRNP A1 and A2 autoantibodies in limited SSc patients and to find their relation to clinical and hand radiographic characteristics.Patients and methods
26 limited SSc patients and 16 matched control were studied. Skin thickness was scored according to the modified Rodnan skin score method (mRss) and radiologic examination by plain X-ray of the hand and wrist was performed anti-hnRNP A1 and A2 were measured in patients and control.Results
All patients were females with a mean age of 37.5 ± 11.24 years and mean disease duration of 7.84 ± 1.19 years. 96.2% of cases showed juxta-articular osteoporosis, 38.5% with marginal erosions, 73.1% with surface erosions, 42.3% with subchondral cyst, 42.3% with metacarpophalangeal subluxation, 11.5% with marginal sclerosis, 80.8% with resorption of distal phalanges, 38.5% with resorption of distal ulna and 34.6% with calcinosis. Anti-hnRNPA1 was positive in all the patients but the anti-hnRNPA2 was positive in 21 (80.8%). Anti-hnRNP A1 and A2 showed significant difference between patients and control (5.66 ± 4.18 ng/ml vs 2.88 ± 0.82; p < 0.01 and 1.82 ± 0.36 vs 0.73 ± 0.08; p < 0.02, respectively). There was no significant correlation between the markers with the mRss or radiographic changes.Conclusion
Joint affection in SSc is more frequent than expected. Anti-hnRNP A1 and anti hnRNP A2 antigens may be useful markers for SSc patient although no significant relation was found with radiologic findings. 相似文献45.
Naiema K. Ali Ragaa R. Mohamed Bothina E. Saleh Manal M. Alkady Eman S. Farag 《Arab Journal Of Gastroenterology》2018,19(3):101-105
Background and study aims
Hepatitis C virus (HCV) infection is a severe problem among patients on maintenance haemodialysis who are at particular risk for blood-borne infections because of prolonged vascular access and potential for exposure to contaminated equipment. Occult hepatitis C virus infection (OCI) is defined as the presence of HCV RNA in liver or peripheral blood mononuclear cells (PBMCs) in the absence of detectable HCV antibody or HCV RNA in the serum. In this study, we aimed to investigate the existence of occult hepatitis C virus infection in PBMCs of haemodialysis (HD) patients in one center. Moreover, we tried to link the condition to risk factors associated with HCV infection in those patients.Patients and methods
We included 40 patients with renal diseases undergoing regular haemodialysis who were repeatedly anti-HCV negative. HCV RNA detection was tested by Quantitative Real time PCR in serum and PBMCs.Results
The results of this study revealed that 23% of our haemodialysis patients have occult hepatitis C virus infection. There was a highly significant increase in ALT levels in patients with OCI versus the negative group. Also, there is a significant increase of history of blood transfusion in patients with occult HCV (p?=?0.03) while the duration of haemodialysis showed no statistical significant difference between both groups. The viral load of the occult hepatitis C virus infection subjects ranged from 581to 74,307 copies/ml.Conclusion
These results highlight the potential risk of hepatitis C virus transmission from patients within haemodialysis units in Egypt. Isolation of patients on dialysis machines depending on the results of hepatitis serological markers is not enough. Testing for hepatitis C virus -RNA in peripheral blood mononuclear cells is more reliable in identifying patients with an OCI when a liver biopsy is not available. 相似文献46.
47.
Hamed NA Hano AF Raouf HA Gamal M Eissa M 《The Egyptian journal of immunology / Egyptian Association of Immunologists》2003,10(1):17-26
The immune system can effectively eliminate hepatitis C virus (HCV) in 15 % of acute hepatitis cases. It is assumed that certain HLA-DR alleles present HCV epitopes more effectively to CD4 helper T cells than do others resulting in vigorous proliferative response to these epitopes and probably HCV recovery. So, we aimed at investigating the frequency of HLA-DRB1*0101 and DRB1*0301 alleles in child and adult haemophilics and in HCV positive hepatocellular carcinoma (HCC) patients in a trial to predict patients who require early therapeutic intervention. We also evaluated interleukin (IL)-12 levels in these patients since IL-12 induces interferon (IFN)-gamma production. This study was conducted on 50 antiHIV negative male patients subdivided into: 25 HCV negative haemophilics (group I), 10 HCV positive haemophilics (group II) and 15 HCV positive HCC (group III). Fifteen healthy persons of matched age and free of HCV and HIV infections were chosen as controls (group IV). All patients and controls were subjected to thorough history taking and clinical examination, routine and diagnostic investigations, viral markers, DRB1*0101 and DRB1*0301 amplification by polymerase chain reaction and plasma IL-12 quantitation by enzyme linked immunosorbent assay (ELISA). The frequencies of DRB1*0101 and DRB1*0301 were 20% and 30% respectively in HCV positive haemophilics and 13.3% and 40%, respectively in HCC. IL-12 levels were significantly lower in HCC cases than in HCV positive haemophilics. Among the haemophilics, IL-12 levels were non-significantly higher in children than in adults and were associated with the given number of blood product bags. DRB1*0101 and DRB1*0301 may have a role in HCV clearance and persistence in Egyptian patients with haemophilia and HCC. Low IL-12 levels encountered in HCV positive haemophilics suggest its relation to immunopathogenesis and outcome of HCV infection. 相似文献
48.
Virological and immunological effects of short-course antiretroviral therapy in primary HIV infection 总被引:4,自引:0,他引:4
Fidler S Oxenius A Brady M Clarke J Cropley I Babiker A Zhang HT Price D Phillips R Weber J 《AIDS (London, England)》2002,16(15):2049-2054
BACKGROUND: National and international guidelines call for the treatment of primary HIV infection (PHI) with combination antiretroviral therapy, although the ideal timing and duration of this intervention is unknown. Recent immunological studies of antiretroviral therapy on small numbers of patients with PHI have reported preservation of HIV-specific CD4 T-helper responses, ordinarily lost in the absence of intervention. We sought to investigate whether a short course of antiretroviral therapy (SCART) at PHI was sufficient to preserve HIV-specific cellular immunity. METHODS: Forty-five subjects with confirmed PHI were offered SCART at diagnosis. HIV specific cellular immune responses and virological parameters were assessed at monthly intervals. RESULTS: Thirty-seven of the subjects chose SCART at PHI, and achieved a plasma viral load < 50 RNA copies/ml by a median of 10 weeks (range, 4-32 weeks). Two of the 45 individuals had evidence of genotypic HIV drug resistance at baseline, and none developed new mutations following therapy. All patients who received SCART at PHI showed preservation of HIV-specific CD4 T-helper responses up to 64 weeks off SCART. CONCLUSION: SCART at PHI was safe, did not induce the development of drug resistance, and appeared sufficient to preserve HIV-specific CD4 T-helper responses. However, PHI is highly heterogeneous, and a large-scale randomized trial of SCART at PHI is now needed. 相似文献
49.
50.
Tawfiq M. Al Antary Hussein Estityah Nizar Haddad Eman T. Al-Antary 《Toxin reviews》2015,34(4):190-194
Chlorinated pesticide residues in human breast milk from five southern Jordan districts were analyzed in 2012/2013. The total number of samples from all districts was 100. The number of samples gathered from each district was collected according to their population densities. The present study shows that 59% of the samples which contained pesticides’ residues were p,p’-DDE, 30% contained β-HCH, 10% contained p,p′-DDT, 6% contained α-HCH, 2% contained heptachlor and 1% contained endrin. These human milk samples were free of aldrin, dieldrin, α-endosulfan, β-endosulfan, HCB, γ-HCH, o,p′-DDD, o,p′-DDT and o,p′-DDE. The levels of the six mentioned compounds detected in all mother’s milk samples were higher in Ghor El-Safi district compared with the other four districts. In this study, it is recommended to continue the pesticides residues monitoring in all parts of Jordan, particularly in Ghor El-Safi district and other regions in the cultivated Jordan Valley. 相似文献