首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   769篇
  免费   48篇
  国内免费   4篇
耳鼻咽喉   2篇
儿科学   40篇
妇产科学   46篇
基础医学   109篇
口腔科学   24篇
临床医学   72篇
内科学   224篇
皮肤病学   24篇
神经病学   44篇
特种医学   14篇
外科学   70篇
综合类   5篇
预防医学   39篇
眼科学   6篇
药学   44篇
中国医学   1篇
肿瘤学   57篇
  2023年   6篇
  2022年   9篇
  2021年   23篇
  2020年   22篇
  2019年   28篇
  2018年   26篇
  2017年   20篇
  2016年   23篇
  2015年   23篇
  2014年   26篇
  2013年   46篇
  2012年   67篇
  2011年   63篇
  2010年   35篇
  2009年   32篇
  2008年   54篇
  2007年   68篇
  2006年   50篇
  2005年   61篇
  2004年   44篇
  2003年   39篇
  2002年   25篇
  2001年   1篇
  2000年   5篇
  1999年   2篇
  1998年   6篇
  1997年   2篇
  1995年   4篇
  1994年   3篇
  1991年   1篇
  1990年   1篇
  1967年   2篇
  1966年   2篇
  1965年   1篇
  1963年   1篇
排序方式: 共有821条查询结果,搜索用时 15 毫秒
51.
Psychotropic medication-induced hyponatraemia is an uncommon but important clinical problem with potential serious consequences if not recognised and treated early. Several risk factors have been associated with the development of hyponatraemia. This article reviews reported cases of hyponatraemia associated with the use of psychotropic medications and evaluates possible risk factors and causes. The data were sourced by a search of Medline for reports of hyponatraemia associated with the use of psychotropic medication between January 1966 and December 2000 and a search of US Food and Drug Administration (FDA) spontaneous reporting system database between January 1966 and December 1999. All the reports were included in this review. In the case reports the following data were assessed: age, gender, daily dosage, days to onset, days to recovery, medical condition, concurrent medications. Several risk factors were identified: advanced age, female gender, use of other medications, medical comorbidity. The risk of hyponatraemia was found to be higher during the first 2 weeks of treatment. Administration of the dosage of the drug was not found to be related to the development of hyponatraemia. Hyponatraemia can cause confusion, agitation and lethargy. Any change in the course of illness should alert the physician to the possibility of hyponatraemia.  相似文献   
52.
A recently developed immunocytochemical technique in HbF-cell counting was assessed by an objective evaluation method. The basic principle of this method is the preparation of aliquots with predetermined HbF-cell (target) values. These aliquots serve as control samples to standardize the HbF-cell measurements by the new immunocytochemical technique, which uses the StreptABComplex/AP staining procedure (SAP) and visualization under white light. Immunofluorescence optical counts (IF) were performed in parallel with the new technique. A trend of inaccuracy was observed in low target values for both methods. As the level of target values increased, deviations became insignificant (relative accuracy < 8%) with SAP having slightly better results. Linear regression data of the estimated %HbF-cell rates by the two methods versus the target values were very satisfactory for both methods with SAP being slightly better. SAP seems to provide an accurate and reliable alternative for HbF-cell estimation comparable with the classical IF optical count.  相似文献   
53.
OBJECTIVE: Quality of life in a treatment-seeking cohort of patients with social anxiety disorder was compared with that of patients with panic disorder who were matched for age, comorbid illnesses, and gender and with population-based norms. METHODS: The study participants were 33 patients with social anxiety disorder and 33 patients with panic disorder who had participated in clinical trials and who had completed the Medical Outcomes Study Short-Form-36 (SF-36) as part of a baseline evaluation. The patients did not have significant comorbid psychiatric disorders. Paired t tests were used to compare baseline scores on subscales of the SF-36 between the two cohorts. One-sample t tests were used to compare scores on subscales of the SF-36 with expectation scores based on 2,474 persons from the general population. RESULTS: Compared with the general population, the patients with social anxiety disorder had significantly greater impairment as measured by the SF-36 social functioning and mental health subscales. Subscale scores also indicated poorer emotional role functioning, but the difference was not significant. However, they were significantly less impaired than the patients with panic disorder in terms of physical functioning, physical role, and mental health. CONCLUSIONS: Patients with social anxiety disorder who do not have significant comorbid depression or anxiety are substantially impaired in quality of life, but to a lesser extent than patients with panic disorder, who suffer from both mental and physical impairments in quality of life.  相似文献   
54.
BACKGROUND AND AIM: Induced sputum (IS) has been proposed as a useful non-invasive method mainly for the assessment of airway diseases. The aim of this study was to evaluate IS cellular composition and T-lymphocyte subpopulations and to compare them with those of bronchoalveolar lavage fluid (BALF) in patients with sarcoidosis. METHODS: We studied prospectively 20 patients (12 female, 8 male) of median age 46 yr (range 25-65) with sarcoidosis and 10 normal subjects (5 female, 5 male) of median age 39 yr (range 26-60). IS was performed with hypertonic saline solution using an ultrasonic nebulizer (De Vilbis 2000). BALF was performed by conventional procedure using fiberoptic bronchoscopy. May-Giemsa-Grunewald stained preps were differentially counted and T-lymphocyte subsets were analyzed by flow activated cell sorter (FACS). RESULTS: The percentage of macrophages was significantly lower in IS than in BALF (p < 0.0001), the percentage of neutrophils was significantly lower in BALF than in IS (p < 0.0001), while there was no difference in the percentage of lymphocytes (p = 0.693) and eosinophils (p = 0.25) in IS vs BALF in patients with sarcoidosis. A significant correlation was found between BALF and IS lymphocyte counts (r = 0.61, p = 0.004), macrophages (r = 0.51, p = 0.02), and CD4+/CD8+ ratio (r = 0.700, p = 0.001). CONCLUSIONS: These results suggest that the inflammation in sarcoidosis could be effectively and non-invasively determined by the analysis of cell differential counts and T-lymphocyte subsets in IS. Further studies are needed to explore the role of IS vs BALF in the follow-up of these patients.  相似文献   
55.
This study was designed to assess human bone marrow cell response and particularly cell adhesion, proliferation, and differentiation, when cultured in vitro on titanium alloy and hydroxyapatite with different values of surface roughness. A further aim was to compare the cell response on the two materials, currently used in spinal surgery. Cell adhesion was determined after 0.5, 2, 4, and 18 hours of incubation; proliferation after 8, 11, 14, and 16 days of culture; and differentiation was evaluated with the expression of alkaline phosphatase activity after 8 and 16 days of culture. This study showed that bone marrow cells grew faster on titanium alloy than on hydroxyapatite, although fewer cells attached to titanium, compared to those attached to hydroxyapatite. No statistically significant difference was observed as the expression of alkaline phosphatase activity on hydroxyapatite and titanium alloy of the same roughness. Cell adhesion, proliferation, and differentiation are dependent on surface roughness of the biomaterial, and all three increased as the roughness of titanium alloy increased. Conclusively, surface roughness of titanium and hydroxyapatite significantly influences bone marrow cell response, and therefore these biomaterials should be used with rough outer surface, if a significant cell response on them is desired. These advantages of titanium and hydroxyapatite theoretically seem to be of particular importance in the following situations: long fusions, lumbosacral fusion, revision surgery with poor bone bank, neuropathic scoliosis associated with few bone graft reserves, and adult patients with severe osteoporosis.  相似文献   
56.
. Oblique midshaft fractures of long bones can be stabilized using either plates and screws, lag screws, wires, cerclages, or a combination of these methods. Fractures at the distal tip of a well-fixed femoral prosthesis are difficult to stabilize with plates and screws because of the underlying intramedullary stem, polymethylmetacrylate (PMMA) cement, and thin periprosthetic femoral cortex. In this study we compared in vitro the mechanical performance of five different osteosynthesis techniques applied on an oak femoral model obliquely oscillated to mimic a short oblique fracture: (a) Double stainless steel wiring; (b) two 4.5 mm lag screws; (c) combination of one 4.5 mm cortical screw and one stainless steel wire; (d) one titanium compression cerclage Gundolf (CCG) combined with one 4.5 mm screw; and (e) double CCG. The five fixation constructs were subjected to a noncyclic destructive axial compression and torsional loading. The highest torque stiffness proved to be the double CCG and the double screw constructs, followed by and combination of CCG-screw and double screw constructs. The mode of failure in torque was a longitudinal crack close to the screw tip and loosening of the CCG and wire. The double screw, double CCG, and screw-CCG constructs provided the highest stiffness in axial compressive forces. The mode of failure in compression was loosening of the CCG and wire and bending of the screw. This comparative study showed that double CCG can theoretically replace the conventional methods of "minimal" osteosynthesis in the midshaft of long bones, and thus shows promise in the treatment of difficult short-oblique type femoral fracture at the distal tip of a well-fixed femoral prosthesis. The advantages of using the CCG is simplicity of technique, biocompatibility of titanium, no interference in modern imaging techniques, and avoidance of stripping of muscles and degloving of bone surfaces, as often happens in platting. Résumé. Etude comparative de la robustesse de cinq systèmes d'ostéosynthèse diaphysaire appliqués à un modèle in vitro d'ostéotomie fémorale. Les fractures diaphysaires obliques peuvent être stabilisées grace à des systèmes vis plaques, vis décalées, fils métalliques ou cerclages, ou encore grace à une combinaison de ces différents systèmes. Les fractures diaphysaires survenant au niveau de l'extrémité distale d'une tige fémorale bien fixée sont difficile à stabiliser par le biais de plaques vissées, en raison de la présence de la tige fémorale, du ciment, et du fin cortex fémoral périprothétique. Nous avons comparé dans cette étude le comportement mécanique "in vitro" de cinq techniques d'ostéosynthèse diaphysaires appliquées à un modèle fémoral en bois de chêne, coupé en son milieu par un plan oblique simulant une fracture courte oblique. Les cinq systèmes testés sont: (a) double ligature inox; (b) 2 vis décalées 4,5 mm; (c) combinaison d'une vis corticale de 4,5 mm et d'une ligature inox (d) un cerclage titane CCG (cerclage de compression de Gundolf) combiné à une vis de 4,5 mm; (e) un double cerclage CCG. Les cinq montages d'ostéosynthèse sont soumis à des chargements non-cycliques jusqu'à rupture, en compression, et en Torsion. La rigidité en Torsion la plus élevée est mesurée pour le double CCG et les deux vis décalées. Les modes de ruptures observés en torsion sont une brèche longitudinale près de l'extrémité des vis, et un desserrage des cerclages et ligatures. Les deux vis, le double CCG et la combinaison Vis-CCG sont les plus rigides en compression. Les modes de rupture observés en compression sont un desserrage des CCG et des ligatures, et un pliage des vis. Cette étude comparative montre que le CCG peut remplacer en théorie les méthodes conventionnelles d'ostéosynthèse diaphysaires "A minima", et est à ce titre très prometteur dans le cadre de fractures diaphysaires courtes obliques en extrémité de tiges fémorales bien fixées.  相似文献   
57.
In the 5-years period, 1996-2000, 1045 children under 13 years old were examined for suspected dermatomycosis. In 611 cases fungi were isolated. Male children were mainly affected on the scalp and body area. Girls were more affected in the location of the arms and legs. There was a greater proportion of cases in the age range 2-12 years. The most prominent fungus was Microsporum canis (515 cases) followed by Trichophyton rubrum (34) and Candida albicans (20). Tinea capitis (280 cases) mainly caused by M. canis (276 cases) was the most common clinical form. Tinea corporis (109 cases) mainly caused by M. canis (88 cases), C. albicans (10 cases) and T. rubrum (seven cases) was the second most frequent clinical form.  相似文献   
58.
PURPOSE: Previous studies have shown that serum levels of the degradation products of cytokeratins could be used as surrogate markers in the diagnosis and followup of patients with solid tumors, including tumors of the bladder. MATERIALS AND METHODS: The soluble cytokeratin 19 fragment CYFRA 21-1 was measured by solid phase radioimmunoassay in the serum of 142 patients with invasive transitional cell cancer of the bladder. Of the patients 56 had clinical stage I to III locally confined disease (T1-4aN0M0) and 86 had stage IV metastatic disease with lymph node and/or distant metastases. A control group consisted of 33 healthy volunteers. In a subgroup of 49 patients with metastatic disease receiving combined platinum based chemotherapy serum CYFRA 21-1 was determined prior to the initiation of therapy and after the documentation of response. RESULTS: Abnormal CYFRA 21-1 was observed in 7% of patients with locally invasive disease and in 66% of those with metastatic disease (p < 0.0001). There was no correlation of CYFRA 21-1 with tumor differentiation. Patients with abnormal CYFRA 21-1 showed statistically significant worse median overall survival. Moreover, in the subgroup of patients with metastatic disease receiving chemotherapy CYFRA 21-1 levels correlated with the response to treatment. CONCLUSIONS: Patients with transitional cell cancer of the bladder with evidence of distant metastases showed a significant increase in serum CYFRA 21-1. During chemotherapy CYFRA 21-1 appears to be a potentially sensitive and useful indicator for monitoring treatment response.  相似文献   
59.
OBJECTIVE: The aim of this study was to investigate the contribution of fibronectin (FN) preadsorption to enhance osteoblast adhesion and strength on hydroxyapatite (HA) used either as osteoconductive bone substitute or precoating of pedicle screws and cages in spine surgery. METHODS: HA substrata with two different surface roughness values (rough HA180 and smooth HA1200) were produced, and human osteoblasts were seeded after culturing on them. Prior to osteoblast seeding, the HA substrata were immersed in FN solution. Osteoblast attachment on each of the two HA substrata was evaluated by recording the number of cells, whereas osteoblast adhesion strength was determined by measuring the shear stress required to detach the cells from the HA substrates. RESULTS: FN preadsorption increased the number of attached osteoblasts on smooth and rough HA substratum at 40% and 62%, respectively, whereas it increased osteoblast attachment strength on the smooth and rough substratum at 165% and 73%, respectively. CONCLUSIONS: This study showed that FN preadsorption and rough HA surface texture synergistically increased "in vitro" both the number and the adhesion strength of human osteoblasts. Further studies in primates and humans should be carried out to disclose the clinical relevance (increase implant's stability and longevity) of the above-mentioned observations.  相似文献   
60.
STUDY OBJECTIVES: Even in high-risk population groups, not all patients have the same risk of sudden cardiac death (SCD). Given the emerging data about the amino-terminal fragment of the brain natriuretic peptide prohormone (NT-proBNP) value in heart failure, we planned to evaluate the importance of NT-proBNP levels in predicting the occurrence of malignant arrhythmias in patients with ischemic cardiomyopathy and implantable cardioverter-defibrillators (ICDs). DESIGN: Prospective study. SETTING: Tertiary referral center. PATIENTS: Thirty five ambulatory patients with previous myocardial infarction, left ventricular ejection fraction < 35%, and ICDs for primary prevention of SCD according to Multicenter Automatic Defibrillator Implantation Trial I criteria. INTERVENTIONS: Venous blood samples for plasma NT-proBNP measurement were obtained after 30 min of supine rest from all patients at the beginning of the study. Patients were evaluated every 2 months, or sooner in cases of device discharges, during a 1-year follow-up period. Data concerning arrhythmias and device therapy were stored at the time of device interrogation on each follow-up visit. MEASUREMENTS AND RESULTS: During 1-year follow-up, 11 of 35 patients (31.4%) received 18 antiarrhythmic device therapies for ventricular tachyarrhythmia (VT). Patients who experienced such arrhythmias had NT-proBNP levels of 997.27 +/- 335.14 pmol/L (mean +/- SD), whereas those without VT had NT-proBNP levels of 654.87 +/- 237.87 pmol/L (p = 0.001). An NT-proBNP cutoff value of 880 pmol/L had a sensitivity of 73%, a specificity of 88%, a positive predictive value of 80%, and a negative predictive value of 88% for the prediction of occurrence-sustained VT events. CONCLUSION: To achieve the maximum benefit by ICD therapy, more precise risk stratification is required, even in high-risk, post-myocardial infarction patients. Plasma NT-proBNP levels comprise a promising method that could help in the better identification of a patient group with an even higher risk of sudden death.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号