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   1072篇
  免费   83篇
  国内免费   39篇
耳鼻咽喉   94篇
儿科学   14篇
妇产科学   20篇
基础医学   44篇
临床医学   201篇
内科学   279篇
皮肤病学   1篇
神经病学   67篇
特种医学   56篇
外科学   188篇
综合类   113篇
预防医学   26篇
眼科学   29篇
药学   32篇
中国医学   18篇
肿瘤学   12篇
  2023年   14篇
  2022年   30篇
  2021年   28篇
  2020年   41篇
  2019年   35篇
  2018年   33篇
  2017年   41篇
  2016年   45篇
  2015年   50篇
  2014年   88篇
  2013年   59篇
  2012年   59篇
  2011年   68篇
  2010年   50篇
  2009年   66篇
  2008年   46篇
  2007年   48篇
  2006年   52篇
  2005年   50篇
  2004年   36篇
  2003年   34篇
  2002年   29篇
  2001年   14篇
  2000年   27篇
  1999年   16篇
  1998年   15篇
  1997年   16篇
  1996年   12篇
  1995年   17篇
  1994年   8篇
  1993年   9篇
  1992年   7篇
  1991年   6篇
  1990年   9篇
  1989年   8篇
  1988年   4篇
  1987年   2篇
  1986年   1篇
  1985年   7篇
  1984年   3篇
  1983年   1篇
  1982年   2篇
  1981年   4篇
  1979年   2篇
  1977年   1篇
  1975年   1篇
排序方式: 共有1194条查询结果,搜索用时 203 毫秒
1.
Although an inverse relationship between body mass index (BMI) and baroreflex sensitivity (BRS) was found, the effect of waist circumference (WC) on BRS is still inconclusive. The contradictory results of previous studies may be related to the heterogeneity and relatively small sample size of the subjects examined. The aim of this population-based study was to investigate whether the influence of increased WC is more detrimental to BRS than BMI. A total of 760 community dwellers were recruited and they were classified into Q1 (n = 189), Q2 (n = 183), Q3 (n = 192) and Q4 (n = 196) groups, based on WC quartiles. Spontaneous BRS was determined by spectral α coefficient method. Valsalva ratio was the longest RR interval after release of Valsalva maneuver divided by the shortest RR interval during maneuver. Cardiac autonomic function was calculated by power spectrum of heart rate in low and high frequency (LF, 0.04–0.15 Hz; HF, 0.15–0.40 Hz), and LF/HF ratio in supine position for five minutes. There were significant differences in spontaneous BRS and Valsalva ratio among different WC groups. In multivariate analysis, obesity was inversely associated with spontaneous BRS and Valsalva ratio. However, these inverse relationships became insignificant after further adjustment for WC quartiles. In contrast, Q4 vs. Q1, Q3 vs. Q1 and Q2 vs. Q1 of WC were inversely related to spontaneous BRS. Q4 vs. Q1 and Q3 vs. Q1 of WC were negatively associated with the Valsalva ratio. In conclusion, increased and even high-normal WC had a stronger adverse effect on BRS than BMI, independent of cardio-metabolic risk factors.  相似文献   
2.
This article was designed to provide a pediatric cardiac computed tomography angiography (CCTA) expert panel consensus based on opinions of experts of the Société Française d’Imagerie Cardiaque et Vasculaire diagnostique et interventionnelle (SFICV) and of the Filiale de Cardiologie Pédiatrique Congénitale (FCPC). This expert panel consensus includes recommendations for indications, patient preparation, CTA radiation dose reduction techniques, and post-processing techniques. The consensus was based on data from available literature (original papers, reviews and guidelines) and on opinions of a group of specialists with extensive experience in the use of CT imaging in congenital heart disease. In order to reach high potential and avoid pitfalls, CCTA in children with congenital heart disease requires training and experience. Moreover, pediatric cardiac CCTA protocols should be standardized to acquire optimal images in this population with the lowest radiation dose possible to prevent unnecessary radiation exposure. We also provided a suggested structured report and a list of acquisition protocols and technical parameters in relation to specific vendors.  相似文献   
3.
4.
5.
1. The aim of the study was to ascertain whether the inhibition of the sympathetic nervous system by angiotensin-converting enzyme (ACE) inhibitors is mediated by endogenous opioids. Naloxone was used to evaluate the effects of the latter on systolic time intervals (STI) and Valsalva manoeuvre-induced blood pressure and heart rate changes. 2. Baseline recordings were done in 12 healthy male volunteers and repeated 2h after oral administration of 75 mg of captopril and again after naloxone 0.4 mg/kg was administered intravenously over 10 min. 3. After captopril there was a significant reduction in systolic (P<0.02) and mean blood pressure (P<0.04) without any changes in heart rate. Furthermore, captopril increased the Valsalva ratio (P<0.06) but did not influence inotropism as indicated by STI. Naloxone did not influence any of these findings. 4. The changes in the Valsalva ratio after captopril were mediated by an increase in the maximum bradycardia in nine of the 12 subjects. 5. The results indicate that endogenous opioids do not play a role in the putative sympatholytic effect of ACE inhibition.  相似文献   
6.
Ruptured sinus of Valsalva aneurysms are rare. We report a case in which the usual clinical manifestations were not present and the patient was initially treated as an acute pulmonary embolus. Despite three negative echocardiograms an intra-cardiac shunt was suspected because of a persistently elevated mixed venous oxygen saturation. Cardiac catheterisation confirmed the diagnosis. Surgical repair was performed and post operative recovery was uneventful.  相似文献   
7.
The purpose of this study was to evaluate the outcome of tension-free vaginal tape (TVT) procedure in women with urodynamic stress incontinence diagnosed as having intrinsic sphincteric deficiency (ISD). The combination of a maximal urethral closure pressure <20 cm H2O and a Valsalva leak point pressure <60 cm H2O was considered as diagnostic of ISD. Subjects with detrusor overactivity on preoperative urodynamics were excluded. A total of 35 patients with both low closure pressure and leak point pressure were enrolled. Bladder perforation occurred in three (8.6%) cases. Postoperative urinary voiding difficulties occurred in nine (25.7%) women. Two patients underwent surgical detension of the tape, with complete resolution of urinary retention and no relapse of incontinence. Women with postoperative voiding dysfunction had a significantly lower detrusorial pressure at the peak flow on preoperative urodynamics compared to those who voided efficiently after TVT. The mean (range) follow-up time was 12.5 months (3–36). The objective cure rate for stress incontinence was 91.4%. Two of the three (66%) patients in whom the TVT procedure failed had a fixed urethra. De novo urge incontinence was found in five (14.3%) patients.  相似文献   
8.
We assessed the relations of visual hallucinations (VH) to cardiovascular autonomic dysfunction in patients with Parkinson's disease (PD). The subjects were 37 patients without VH (VH(-)) and 31 with VH (VH(+)). Autonomic function was evaluated on the basis of cardiac 123-radioiodinated metaiodobenzylguanidine (123I-MIBG) uptake and hemodynamic testing with Valsalva maneuver. Systolic blood pressure (SBP) and plasma norepinephrine concentrations (NE) were measured by tilt-table testing. 123I-MIBG uptake was lower in VH(+) than VH(-). Hemodynamic studies showed that VH(-) had only cardiac sympathetic and parasympathetic dysfunction, while VH(+) additionally had reduced vasomotor sympathetic functions. The fall in SBP during tilt-table testing was greater in VH(+) than VH(-). NE and its difference in the supine and upright positions were decreased in VH(+). We conclude that cardiac and vasomotor sympathetic dysfunction is more severe in VH(+) than in VH(-). Severe dysfunction in PD with VH is probably attributed to Lewy-body lesions or neuronal loss in sympathetic ganglia, the central autonomic system, or both.  相似文献   
9.
同时性后半规管与水平半规管性良性位置性眩晕   总被引:6,自引:1,他引:5  
目的:探讨同时性后半规管与水平半规管性良性位置性眩晕(混合性良性位置性眩晕)的诊治方法。方法:联合应用Epley手法和Barbecue翻滚法对4例患者进行治疗,两次治疗间隔1d。结果:4例患者眩晕症状完全消失,随访至今无复发。结论:混合性良性位置性眩晕兼有后半规管与水平半规管性良性位置性眩晕的临床表现,联合采用Epley手法和Barbecue翻滚法治疗该病是可行的。  相似文献   
10.
军队官兵演习后期的心理变化   总被引:2,自引:1,他引:1  
为探讨军队官兵在演习后期的心理变化,本分析了军队官兵在演习后期存在放松心理,思乡情绪,自我肯定以及发泄心理等的原因,并提出了相关对策;为稳定演习官兵的思想情绪提供参考。  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