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   1311篇
  免费   83篇
  国内免费   3篇
耳鼻咽喉   96篇
儿科学   59篇
妇产科学   32篇
基础医学   186篇
口腔科学   24篇
临床医学   109篇
内科学   192篇
皮肤病学   9篇
神经病学   109篇
特种医学   53篇
外科学   323篇
综合类   3篇
预防医学   60篇
眼科学   18篇
药学   46篇
中国医学   1篇
肿瘤学   77篇
  2023年   12篇
  2022年   11篇
  2021年   36篇
  2020年   23篇
  2019年   40篇
  2018年   41篇
  2017年   45篇
  2016年   54篇
  2015年   40篇
  2014年   48篇
  2013年   56篇
  2012年   74篇
  2011年   71篇
  2010年   50篇
  2009年   55篇
  2008年   61篇
  2007年   71篇
  2006年   58篇
  2005年   48篇
  2004年   55篇
  2003年   53篇
  2002年   41篇
  2001年   32篇
  2000年   24篇
  1999年   24篇
  1998年   16篇
  1997年   18篇
  1996年   19篇
  1995年   13篇
  1994年   12篇
  1993年   14篇
  1992年   19篇
  1991年   17篇
  1990年   12篇
  1989年   14篇
  1988年   8篇
  1987年   8篇
  1986年   6篇
  1984年   4篇
  1983年   7篇
  1981年   4篇
  1967年   4篇
  1966年   4篇
  1960年   4篇
  1956年   4篇
  1942年   3篇
  1941年   4篇
  1936年   4篇
  1932年   6篇
  1930年   3篇
排序方式: 共有1397条查询结果,搜索用时 125 毫秒
81.
82.
BACKGROUND: Coenzyme Q10 (CoQ10) protects myocardium from ischemia-reperfusion (IR) injury as evidenced by improved recovery of mechanical function, ATP, and phosphocreatine during reperfusion. This protection may result from CoQ10's bioenergetic effects on the mitochondria, from its antioxidant properties, or both. The purpose of this study was to elucidate the effects of CoQ10 supplementation on mitochondrial function during myocardial ischemia-reperfusion using an isolated mitochondrial preparation. METHODS: Isolated hearts (n = 6/group) from rats pretreated with liposomal CoQ10 (10 mg/kg iv, CoQ10), vehicle (liposomal only, Vehicle), or saline (Saline) 30 min before the experiments were subjected to 15 min of equilibration (EQ), 25 min of ischemia (I), and 40 min of reperfusion (RP). Left ventricular-developed pressure (DP) was measured. Mitochondria were isolated at end-equilibration (end-EQ), at end-ischemia (end-I), and at end-reperfusion (end-RP). Mitochondrial respiratory function (State 2, 3, and 4, respiratory control index (RCI, ratio of State 3 to 4), and ADP:O ratio) was measured by polarography using NADH (alpha-ketoglutarate, alpha-KG)- or FADH (succinate, SA)-dependent substrates. RESULTS: CoQ10 improved recovery of DP at end-RP (67 +/- 11% in CoQ10 vs 47 +/- 5% in Vehicle and 50 +/- 11% in Saline, P < 0.05 vs Vehicle and Saline). CoQ10 did not change preischemic mitochondrial function. IR decreased State 3 and RCI in all groups using either substrate. CoQ10 had no effect in the mitochondrial oxidation of alpha-KG at end-I. CoQ10 improved State 3 at end-I when SA was used (167 +/- 21 in CoQ10 vs 120 +/- 10 in Saline and 111 +/- 10 ng-atoms O/min/mg protein in Vehicle, P < 0.05). Using alpha-KG as a substrate, CoQ10 improved RCI at end-RP (4.2 +/- 0.2 in CoQ10 vs 3.2 +/- 0.2 in Saline and 3.0 +/- 0.3 in Vehicle, P < 0.05). Using SA, CoQ10 improved State 3 (181 +/- 10 in CoQ10 vs 142 +/- 9 in Saline and 140 +/- 12 ng-atoms O/min/mg protein in Vehicle, P < 0.05) and RCI (2.21 +/- 0.06 in CoQ10 vs 1.85 +/- 0.11 in Saline and 1.72 +/- 0.08 in Vehicle, P < 0.05) at end-RP. CONCLUSIONS: The cardioprotective effects of CoQ10 can be attributed to the preservation of mitochondrial function during reperfusion as evidenced by improved FADH-dependent oxidation.  相似文献   
83.
In spite of anatomical preservation of the internal jugular vein (IJV), an occlusion rate of the vessel of up to 30% has been documented after selective or modified radical neck dissections. The aim of the present prospective study was to evaluate the patency of the IJV following selective lateral neck dissection (LND) in 34 patients affected by squamous cell carcinoma of the upper aerodigestive tract who underwent surgery concomitantly on the primary site and the neck. Eighteen patients received unilateral and 16 bilateral LND, for a total of 50 IJVs. Postoperative radiotherapy on the neck was delivered in four patients with histologic evidence of micro-extracapsular spread; the impact of this variable on IJV patency was assessed by the Fisher test. A preoperative baseline study of vein patency and flow by ultrasonography (US) was obtained. Postoperative controls were scheduled at 1 week, 1 month and 3 months following surgery. No patient developed either wound infection or a pharyngocutaneous fistula, and no signs or symptoms of IJV occlusion were observed during the postoperative course. At the first US control, 25 IJVs (50%) did not present any alteration in patency, and 23 (46%) and 2 (4%) had a reduced or absent flow, respectively. At the second and third controls, 33 (66%) and 45 (90%) of the IJVs presented with normal flow, respectively. At the end of the study, none of the patients showed evidence of occlusion. Postoperative radiotherapy did not have a statistically significant impact on IJV patency ( P=0.09). In conclusion, long-term IJV occlusion after LND has to be considered an exceedingly rare event with negligible morbidity. However, alterations of IJV flow frequently occur in the immediate postoperative course.  相似文献   
84.
85.
In 2 patients, a man aged 30 and a woman aged 31, a hyperextension trauma of the proximal interphalangeal joint of the right index finger and the left middle finger respectively was diagnosed. The man underwent surgery for volar plate rupture in the acute phase. The woman presented 7 weeks after the trauma with a chronic flexion contracture; she had an avulsion fracture of the second phalanx and was treated conservatively with splints and exercise therapy. The hyperextension trauma of the proximal interphalangeal joint of a finger is one of the most frequently occurring hand traumas. In the more severe cases, there can be substantial damage to the structures ofthe joint capsule, such as a volar plate rupture. In the acute phase, a ruptured volar plate results in pain and dorsal dislocation. In the long term however, two significant late complications can arise: the chronic post-traumatic hyperextension deformity and the flexion contracture. These complications are difficult to treat, but can be prevented by adequate initial treatment. The diagnosis of volar plate rupture is essential to this and can be formulated after a carefully conducted history taking and physical examination usually with simple radiological studies ofthe affected digit. Treatment of a volar plate rupture can be either conservative or surgical and is directed at regaining finger function and preventing complications. For the treatment to be successful, intensive physiotherapy during follow-up is essential.  相似文献   
86.
Morbid obesity is associated with and increased risk of serious comorbidities, including type 2 diabetes, sleep apnoea, cardiovascular diseases, and orthopedic disabilities. Not operative treatments for superobese patients have not been shown to produce reliable long-term benefits, therefore surgical therapy has became the treatment of choice. The number of surgical procedures increased in the last year confirm these data. However, before recommended a specific surgical procedures to a superobese patients it is necessary to consider some variables, such as: patient, health structure, and multidisciplinary equipe. Since there are not recommended or condemned surgical procedures, in this paper the Authors tried to evaluate the effectiveness and limits of the most performed surgical procedures for the treatment of pathologic obesity: gastric by-pass, biliopancreatic diversion (duodenal switch), vertical gastroplasty, banding gastric. The Authors used some pointer of outcome to measure effectiveness and limits: five year post-operative percentage excess weight loss >/< 50, peri-operative >/< 1%, early and late complications >/< 15%, reoperation >/< 3%, improvement of quality of life. Thanks to new surgical technique, restrictive options are losing ground, while malabsorbitive bariatric procedures are collecting successful.  相似文献   
87.
OBJECTIVE: To assess benign prostatic hyperplasia (BPH) and erectile dysfunction (ED), both considered to be associated with urogenital ageing, in ageing men in a cross-sectional population study, comparing them with healthy controls by using symptom scores and contrast-enhanced colour Doppler ultrasonography (CDUS). PATIENTS, SUBJECTS AND METHODS: Transrectal CDUS and quantitative measurement of colour pixel intensity (CPI) are excellent minimally invasive techniques for assessing normal and pathological blood flow. CDUS was performed using the microbubble-based ultrasound enhancer for evaluating prostate, bladder neck and corpus cavernosum vascularity in young healthy men, men with BPH, and men with severe vascular damage (diabetes mellitus type 2). Resistive index measurements and computer-assisted quantification of CPI were used to objectively evaluate perfusion. The International Prostate Symptom Score (IPSS) and the International Index of Erectile Function (IIEF) were applied to quantify the symptoms. RESULTS: In patients with BPH, perfusion of the transition zone (TZ) of the prostate was significantly lower and the resistive index of the TZ significantly higher (both P < 0.001) than in healthy controls. The perfusion patterns of men with BPH and those who also had severe vascular damage (diabetes mellitus type 2) showed that vascularity in the latter group was lower in the prostatic TZ and the corpora cavernosa. In patients with BPH the IPSS, quality-of-life and IIEF scores were significantly worse than in the control group. Men with concomitant atherosclerosis had even worse symptom scores. CONCLUSION: These results strongly support the hypothesis that age-related impairment of blood supply to the lower urinary tract is important in the development of BPH and ED. Vascular damage may cause chronic ischaemia and thus be a contributing factor in the pathogenesis of BPH and ED.  相似文献   
88.
89.
Fibrous dysplasia (FD) is a non-neoplastic, expansile lesion of unknown origin. In about one-fourth of cases this disorder affects the head and neck area, where the mandible and maxilla are the most frequently involved sites. Its localization to the ethmoid is a rare event. Since the disease slowly progresses, its management is delayed until significant clinical symptoms or non-well-tolerated aesthetic deformities are present. When required, surgery is the treatment of choice. Several external procedures have been used to manage the lesion, but recently, more conservative transnasal approaches have been proposed. We report the history of a 6-year-old boy with fibrous dysplasia of the ethmoid labyrinth that underwent successful transnasal endoscopic removal. Furthermore, an analysis of the literature is presented with particular emphasis on clinical picture, diagnosis, and treatment of this rare illness.  相似文献   
90.
Bindl L  Nicolai T 《Klinische P?diatrie》2005,217(Z1):S130-S142
Septic shock occurs in 6 % of paediatric cancer patients with neutropenia and fever. The mortality of the septic shock is 40 % in BMT patients and 5 % in others. One third of paediatric ARDS cases affect immunocompromised individuals with a total mortality of 45 % and 80 % after BMT. Septic shock is caused by gram-negative bacteria in more than 75 %. ARDS is due to pneumonia in more than 50 %, sepsis in about 25 %. This article provides the recommendations of the Infectious Diseases Working Party of the German Society for Pediatric Infectious Diseases (DGPI) and the German Society for Pediatric Hematology/Oncology (GPOH) for treatment of septic shock and ARDS. Therapy of septic shock includes early antibiotic therapy and volume expansion (> or = 40 ml/kg initially). Refractory shock requires vasopressors (noradrenaline), followed by a judicious circulatory management. Hydrocortisone is indicated in patients with high probability of adrenal insufficiency. Mainstay of ARDS therapy is ventilation with sufficient end-expiratory pressure (PEEP) to prevent loss of functional residual capacity and with limited tidal volumes (< or = 6 ml/kg) and limited inspiratory pressure (< 35 cm H(2)O) respectively, to minimize ventilator induced lung injury. Volume therapy consists of maintenance of sufficient preload to counteract the impaired venous return, induced by positive pressure ventilation. Diuretics and eventually veno-venous haemofiltration are used to reduce free lung water. Surfactant application may be considered in severe cases. Steroids are indicated in pneumocystis carinii pneumonia and in engraftment pneumonitis.  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