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   1267篇
  免费   94篇
  国内免费   2篇
耳鼻咽喉   66篇
儿科学   15篇
妇产科学   9篇
基础医学   90篇
口腔科学   32篇
临床医学   99篇
内科学   363篇
皮肤病学   4篇
神经病学   62篇
特种医学   19篇
外科学   318篇
综合类   12篇
一般理论   1篇
预防医学   58篇
眼科学   9篇
药学   21篇
肿瘤学   185篇
  2023年   7篇
  2021年   7篇
  2019年   20篇
  2018年   11篇
  2017年   11篇
  2016年   8篇
  2015年   23篇
  2014年   25篇
  2013年   54篇
  2012年   62篇
  2011年   63篇
  2010年   40篇
  2009年   39篇
  2008年   53篇
  2007年   50篇
  2006年   52篇
  2005年   64篇
  2004年   59篇
  2003年   54篇
  2002年   68篇
  2001年   58篇
  2000年   57篇
  1999年   40篇
  1998年   14篇
  1997年   11篇
  1996年   5篇
  1994年   7篇
  1993年   7篇
  1992年   30篇
  1991年   33篇
  1990年   35篇
  1989年   28篇
  1988年   22篇
  1987年   25篇
  1986年   23篇
  1985年   24篇
  1984年   19篇
  1983年   11篇
  1981年   6篇
  1979年   14篇
  1978年   5篇
  1977年   8篇
  1976年   6篇
  1975年   7篇
  1974年   9篇
  1973年   14篇
  1972年   15篇
  1971年   5篇
  1970年   8篇
  1968年   7篇
排序方式: 共有1363条查询结果,搜索用时 15 毫秒
1.
IntroductionMisophonia is characterized by the aversion to very selective sounds, which evoke a strong emotional reaction. It has been inferred that misophonia, as well as tinnitus, is associated with hyperconnectivity between auditory and limbic systems. Individuals with bothersome tinnitus may have selective attention impairment, but it has not been demonstrated in case of misophonia yet.ObjectiveTo characterize a sample of misophonic subjects and compare it with two control groups, one with tinnitus individuals (without misophonia) and the other with asymptomatic individuals (without misophonia and without tinnitus), regarding the selective attention.MethodsWe evaluated 40 normal-hearing participants: 10 with misophonia, 10 with tinnitus (without misophonia) and 20 without tinnitus and without misophonia. In order to evaluate the selective attention, the dichotic sentence identification test was applied in three situations: firstly, the Brazilian Portuguese test was applied. Then, the same test was applied, combined with two competitive sounds: chewing sound (representing a sound that commonly triggers misophonia), and white noise (representing a common type of tinnitus which causes discomfort to patients).ResultsThe dichotic sentence identification test with chewing sound, showed that the average of correct responses differed between misophonia and without tinnitus and without misophonia (p = 0.027) and between misophonia and tinnitus (without misophonia) (p = 0.002), in both cases lower in misophonia. Both, the dichotic sentence identification test alone, and with white noise, failed to show differences in the average of correct responses among the three groups (p ≥ 0.452).ConclusionThe misophonia participants presented a lower percentage of correct responses in the dichotic sentence identification test with chewing sound; suggesting that individuals with misophonia may have selective attention impairment when they are exposed to sounds that trigger this condition.  相似文献   
2.
An emerging technology that encompasses computed tomography, cone-beam computed tomography, and interactive software applications has slowly progressed and evolved into a necessary tool for diagnosis, treatment planning, and delivery of dental implant and associated restorative and surgical procedures. The integration of these innovative tools is helping to define new methods for appreciating anatomy, improving accuracy, and enhancing presurgical prosthetic planning to achieve true restorative-driven implant dentistry. This article will demonstrate how computed tomography combined with interactive virtual treatment-planning software applications can empower clinicians with enhanced diagnostic capabilities for implant receptor-site assessment, generating new paradigms that eventually may supersede older methods of presurgical planning for dental implant reconstruction.  相似文献   
3.
We tested the in vitro susceptibility of Candida albicans to three defensins from human neutrophilic granulocytes (HNP-1, 2, and 3), a homologous defensin from rabbit leukocytes (NP-1), and four unrelated cationic peptides. Although the primary amino acid sequences of HNP-1, 2, and 3 are identical except for a single amino-terminal amino acid alteration, HNP-1 and HNP-2 killed C. albicans but HNP-3 did not. C. albicans blastoconidia were protected from HNP-1 when incubations were performed in the absence of oxygen or in the presence of inhibitors that blocked both of its mitochondrial respiratory pathways. Neither anaerobiosis nor mitochondrial inhibitors substantially protected C. albicans exposed to NP-1, poly-L-arginine, poly-L-lysine, or mellitin. Human neutrophilic granulocyte defensin-mediated candidacidal activity was inhibited by both Mg2+ and Ca2+, and was unaffected by Fe2+. In contrast, Fe2+ inhibited the candidacidal activity of NP-1 and all of the model cationic peptides, whereas Mg2+ inhibited none of them. These data demonstrate that susceptibility of C. albicans to human defensins depends both on the ionic environment and on the metabolic state of the target cell. The latter finding suggests that leukocyte-mediated microbicidal mechanisms may manifest oxygen dependence for reasons unrelated to the production of reactive oxygen intermediates by the leukocyte.  相似文献   
4.
Endothelium-dependent vasodilation is impaired in humans with diabetes mellitus. Inactivation of endothelium-derived nitric oxide by oxygen-derived free radicals contributes to abnormal vascular reactivity in experimental models of diabetes. To determine whether this observation is relevant to humans, we tested the hypothesis that the antioxidant, vitamin C, could improve endothelium-dependent vasodilation in forearm resistance vessels of patients with non-insulin-dependent diabetes mellitus. We studied 10 diabetic subjects and 10 age-matched, nondiabetic control subjects. Forearm blood flow was determined by venous occlusion plethysmography. Endothelium-dependent vasodilation was assessed by intraarterial infusion of methacholine (0.3-10 micrograms/min). Endothelium-independent vasodilation was measured by intraarterial infusion of nitroprusside (0.3-10 micrograms/min) and verapamil (10-300 micrograms/min). Forearm blood flow dose-response curves were determined for each drug before and during concomitant intraarterial administration of vitamin C (24 mg/min). In diabetic subjects, endothelium-dependent vasodilation to methacholine was augmented by simultaneous infusion of vitamin C (P = 0.002); in contrast, endothelium-independent vasodilation to nitroprusside and to verapamil were not affected by concomitant infusion of vitamin C (P = 0.9 and P = 0.4, respectively). In nondiabetic subjects, vitamin C administration did not alter endothelium-dependent vasodilation (P = 0.8). We conclude that endothelial dysfunction in forearm resistance vessels of patients with non-insulin-dependent diabetes mellitus can be improved by administration of the antioxidant, vitamin C. These findings support the hypothesis that nitric oxide inactivation by oxygen-derived free radicals contributes to abnormal vascular reactivity in diabetes.  相似文献   
5.
Canady J  Hargrove M  Ganz A 《AANA journal》2001,69(5):399-404
The present study was conducted to compare the incidence of transient radicular irritation (TRI) after spinal anesthesia with 5% lidocaine or 0.75% bupivacaine in the supine, prone, and lithotomy surgical positions. A non-rAndomized survey approach was used. The convenience sample consisted of 243 adults receiving spinal anesthesia for elective surgery at 1 of 3 hospitals. Patients were questioned by telephone postoperatively to determine whether they had experienced TRI. Statistical analysis using the Fisher exact test revealed no significant difference in TRI incidence between local anesthetics in the supine or prone position groups. In the lithotomy position group, the incidence of TRI was significantly higher in patients receiving 5% lidocaine. Further, chi 2 testing revealed no significant difference in TRI incidence between surgical position groups when position alone was considered. The findings suggest that TRI after spinal anesthesia occurs more frequently with 5% lidocaine than with 0.75% bupivacaine only when patients undergo surgery in the lithotomy position. Providers need to consider the risks and benefits of 5% lidocaine when selecting an agent for spinal anesthesia, especially with patients undergoing surgery in the lithotomy position. When lidocaine is used, providers should discuss TRI as a risk of spinal anesthesia with patients during preanesthetic counseling.  相似文献   
6.
7.
8.
9.
OBJECTIVES: We sought to characterize re-entry circuits causing intra-atrial re-entrant tachycardias (IARTs) late after the repair of congenital heart disease (CHD) and to define an approach for mapping and ablation, combining anatomy, activation sequence data and entrainment mapping. BACKGROUND: The development of IARTs after repair of CHD is difficult to manage and ablate due to complex anatomy, variable re-entry circuit locations and the frequent co-existence of multiple circuits. METHODS: Forty-seven re-entry circuits were mapped in 20 patients with recurrent IARTs refractory to medical therapy. In the first group (n = 7), ablation was guided by entrainment mapping. In the second group (n = 13), entrainment mapping was combined with a three-dimensional electroanatomic mapping system to precisely localize the scar-related boundaries of re-entry circuits and to reconstruct the activation pattern. RESULTS: Three types of right atrial macro-re-entrant circuits were identified: those related to a lateral right atriotomy scar (19 IARTs), the Eustachian isthmus (18 IARTs) or an atrial septal patch (8 IARTs). Two IARTs originated in the left atrium. Radiofrequency (RF) lesions were applied to transect critical isthmuses in the right atrium. In three patients, the combined mapping approach identified a narrow isthmuses in the lateral atrium, where the first RF lesion interrupted the circuit; the remaining circuits were interrupted by a series of RF lesions across a broader path. Overall, 38 (81%) of 47 IARTs were successfully ablated. During follow-up ranging from 3 to 46 months, 16 (80%) of 20 patients remained free of recurrence. Success was similar in the first 7 (group 1) and last 13 patients (group 2), but fluoroscopy time decreased from 60 +/- 30 to 24 +/- 9 min/procedure, probably related to the increasing experience and ability to monitor catheter position non-fluoroscopically. CONCLUSIONS: Entrainment mapping combined with three-dimensional electroanatomic mapping allows delineation of complex re-entry circuits and critical isthmuses as targets for ablation. Radiofrequency catheter ablation is a reasonable option for treatment of IARTs related to repair of CHD.  相似文献   
10.
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