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   777篇
  免费   55篇
  国内免费   2篇
耳鼻咽喉   5篇
儿科学   63篇
妇产科学   42篇
基础医学   52篇
口腔科学   36篇
临床医学   80篇
内科学   130篇
皮肤病学   18篇
神经病学   63篇
特种医学   30篇
外科学   223篇
综合类   12篇
预防医学   9篇
眼科学   15篇
药学   35篇
中国医学   2篇
肿瘤学   19篇
  2023年   9篇
  2022年   7篇
  2021年   30篇
  2020年   12篇
  2019年   16篇
  2018年   25篇
  2017年   25篇
  2016年   38篇
  2015年   33篇
  2014年   37篇
  2013年   55篇
  2012年   67篇
  2011年   83篇
  2010年   28篇
  2009年   26篇
  2008年   49篇
  2007年   65篇
  2006年   62篇
  2005年   49篇
  2004年   42篇
  2003年   18篇
  2002年   20篇
  2001年   13篇
  2000年   4篇
  1999年   6篇
  1998年   1篇
  1997年   3篇
  1996年   5篇
  1995年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1987年   1篇
  1985年   1篇
排序方式: 共有834条查询结果,搜索用时 78 毫秒
1.
OBJECTIVE: To evaluate the possible effects of sex and age on strength-duration time constant (SDTC). METHODS: The SDTC of 126 healthy volunteers was measured following stimulation of right median nerve at the wrist. Variations in values were evaluated according to sex and age. RESULTS: The SDTC was 438.6+/-114.5 micros in women and 396.2+/-90.3 in men (P=.023). In men, as age increased, so did SDTC. However, this was not true in women. Comparing the values of women and men, aged below 40, demonstrated a difference in excitability, confined to younger patients. CONCLUSIONS: As SDTC depends on the biophysical properties of the axonal membrane and can provide some information about Na(+) channel function, these data raise the possibility of a difference in Na(+) channel function between men and women and a difference in the conductance with age. SIGNIFICANCE: The age- and sex-related differences shown in this study suggest a possible biochemical or hormonal influence on axonal excitability.  相似文献   
2.
OBJECTIVE: Hyperventilation and ischaemia increase axonal excitability by changing Na+ conductance in healthy subjects. However, the changes in excitability during and after ischaemia in diabetic patients are less than in healthy controls. This is known as ischaemic resistance. In this study, we investigated the effects of hyperventilation for 20 min on strength-duration time constant (SDTC) of motor axons of the median nerve of diabetic patients with polyneuropathy to determine whether diabetics are less affected by hyperventilation, a form of resistance similar to the ischaemic resistance of diabetics. METHODS: The SDTC of 14 diabetic patients with polyneuropathy and 10 healthy volunteers were measured following stimulation of right median nerve at the wrist prior to and after hyperventilation for 20 min. RESULTS: There was a significant increase in the SDTC in control subjects, but no significant change in the SDTC for patients with diabetic polyneuropathy. The score of the clinical response (paraesthesiae and carpopedal spasm) to hyperventilation of controls was also significantly greater in the controls than the patients. CONCLUSION: Hyperventilation for 20 min has little influence on SDTC in patients with diabetic polyneuropathy. SIGNIFICANCE: The 'resistance' of diabetic nerve is not confined to ischaemia but involves other manoeuvres that can alter axonal excitability.  相似文献   
3.
Metastatic carcinoma to the testis is very rare. Metastasis of prostate adenocarcinoma to testis was detected incidentally after bilateral orchiectomy for hormonal management of metastatic prostate carcinoma. The metastatic lesion was not identified in physical examination or in macroscopic dissection of the testis after surgery. Microscopy revealed an adenocarcinoma which, given the history of the patient and a positive immunohistochemical stain for PSA, was identified as metastatic prostatic adenocarcinoma.  相似文献   
4.
Spinal osteochondromas are very rare, and they present with nonspecific localized pain owing to bone involvement. Diagnosis is made based on direct X-ray and computed tomography (CT) imaging of the exophytic bone lesion with pedunculated or sessile structure. Although asymptomatic patients can be observed, surgical excision is the main treatment modality. We present the case of a 34-year-old man with solitary thoracic osteochondroma. The patient presented with complaints of pain in the legs, numbness, and inability to walk. The diagnosis was confirmed with CT imaging showing calcified heterogeneous bone lesion originating from the left side of T1-2 facet joint. After total excision, histopathological examination revealed the diagnosis of osteochondroma. No new clinical or radiological findings were detected in the 10-month follow-up.  相似文献   
5.
Stress and sulfite can stimulate numerous pathways leading to an increased production of free radicals which generate a peroxidation cascade producing lipid peroxidation, protein oxidation, DNA damage and cell death, and contribute to the occurrence of pathologic conditions. The purpose of our study was to investigate the effects of stress and sulfite on visual evoked potentials (VEPs) and to examine the relationship between lipid peroxidation and VEP changes. Forty male wistar rats, aged three months were used. They were equally divided into four groups: control (C), the group exposed to restraint stress (R), the group treated with sulfite (S) and the group exposed to stress and treated with sulfite (RS). Chronic restraint stress was applied for 21 days (1h/day) and sodium metabisulfite (520 mg/kg/day) was given by gavage for the same period. All latencies of VEP components were prolonged in the R, S and RS groups with respect to the C group. Brain and retina TBARS levels were found to be increased in those groups compared to the C group. Our results strongly suggest that the latency prolongations of all VEP components may have resulted from the enhancement of lipid peroxidation. Correlation analysis between brain and retina TBARS levels and VEP latencies also support this conclusion. Our data in regard to latency prolongations of all VEP components in the stress group exposed to sulfite, reflected an additive effect of sulfite toxicity on VEP components. Therefore it could be suggested that chronic exposure to stress and sulfite together is associated with a considerable health risk.  相似文献   
6.
There have been few reports about skeletal changes beneath a tissue expander in breast reconstruction. We present one, and surgeons should be cautious about the possibility of skeletal deformities in patients who are osteoporotic and postmenopausal who require prolonged tissue expansion.  相似文献   
7.
Alopecia areata (AA) and vitiligo (V) are diseases that are correlated with psychiatric disorders before, during and after diagnosis. The Temperament and Character Inventory (TCI) is a well‐established approach for investigating personality traits in various psychosomatic diseases. The aim of this study is to compare and investigate the differences in the TCI between patients with first onset AA, patients with V and healthy controls (HC). Participants in the study included 42 patients with first onset AA, 50 adult patients with V and 60 HC who had no history or diagnoses of psychiatric or dermatological disorders. All participants were assessed with the TCI and the Dermatology Life Quality Index (DLQI). Among the temperament traits, the extravagance, disorderliness and total novelty‐seeking scores were lower, and the worry and pessimism scores were higher in patients with V compared with patients with AA and the HC. The mean score of the enlightened second nature and the total self‐directedness score of the character traits were higher in patients with V compared with patients with AA and the HC group. In the AA group, there was a negative correlation only between the reward dependence total score and the DLQI score. This study suggests that patients with first onset V have a distinct temperament, such as being unenthusiastic and unemotional, and character profiles, such as worry and pessimism, independent of their psychiatric comorbidities, and patients with AA do not have a different personality from the non‐affected population.  相似文献   
8.
The objective of this study was to evaluate the safety and efficacy of flexible ureteroscopy (FURS) and holmium:YAG laser lithotripsy for the treatment of upper urinary tract stones in patients on active oral anticoagulants. The records of 1081 patients who underwent flexible ureteroscopic holmium:YAG (Ho:YAG) laser lithotripsy for upper ureteral and renal calculi from 1999 to 2015 were retrospectively reviewed. A total of 84 patients on continuous oral anticoagulation or antiplatelet therapy (warfarin, aspirin, or clopidogrel) were identified. Of these patients, 40 were on warfarin, 25 on aspirin, 11 on clopidogrel, and 8 on both aspirin and clopidogrel. The drugs were not discontinued. The baseline characteristics, indications for anticoagulation therapy, perioperative data, stone-free rate, and complications were documented. Evaluation of outcomes was assessed at 1-, 3-, and 6-month follow-up postoperatively. Mean stone size was 19.7 ± 9.4 (range 8 to 31 mm). Twenty patients had upper ureteral and 64 patients had intrarenal calculi. Two patients had bilateral renal calculi. Mean operation time was 78.2 ± 23.8 min (range 17 to 144 min). Two procedures (2.3%) in warfarin group were terminated due to persistent bleeding causing visual impairment. No transfusions were required. The mean serum hemoglobin levels did not change significantly (12.9 ± 3.7 to 12.2 ± 3.3 g/dL). No thromboembolic or cardiac adverse events were observed perioperatively. The double-j (DJ) ureteral catheterization time was 29.6 ± 9.3 days (range 14 to 68 days) and the hospital stay was 1.6 ± 0.6 days (range 1 to 4). The stone-free rate was 95.2% (80 patients) at 6 months. Flexible ureteroscopic Ho:YAG laser lithotripsy in patients requiring long-term anticoagulation therapy seems to be a safe and effective procedure and should be considered as a first-line treatment option in such patients for the surgical management of upper urinary tract stones.  相似文献   
9.
OBJECTIVES: The purpose of our study was to evaluate the significance of polymorphisms in HLA class II genes in coronary artery ectasia (CAE) patients. METHODS AND RESULTS: Twenty-six patients with CAE without associated cardiac defects were enrolled in the study. CAE was defined as luminal dilation of 1.5- to 2.0-fold of normal limits. Ninety-five healthy subjects who were donors for different organ transplantations, were chosen as control group. Physical examination, electrocardiography and chest X-ray were completely normal in these cases. Both the patients and the control group were screened and compared for their HLA class II genotypes. HLA-DR B1*13, DR16, DQ2 and DQ5 genotypes were significantly more frequent in the patient group.When the known risk factors of coronary heart disease were compared in the patients carrying these genotypes with the non-carrying group, no significant differences were encountered. CONCLUSIONS: HLA-DR B1*13, DR16, DQ2 and DQ5 may be associated with the pathogenesis and increase the risk of CAE.  相似文献   
10.
Hemophilia is a hereditary disease with impaired blood coagulation due to a genetic deficiency of blood coagulation factors. The development of inhibitors further complicates the course of the disease and management. The case is here reported of a haemophilia patient who presented with coexisting development of high titer inhibitor with Gastrointestinal Stromal Tumor (GIST) diagnosis and was admitted with upper gastrointestinal system bleeding. The patient had no prior history of inhibitor presence. During all procedures including surgery, excellent hemostasis was achieved with rFVIIa treatment and no hemorrhagic complication was observed. To the best of our knowledge, this constitutes the first reported case of GIST associated with inhibitor development in a hemophilia A patient.  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