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   939篇
  免费   55篇
  国内免费   3篇
耳鼻咽喉   7篇
儿科学   24篇
妇产科学   24篇
基础医学   76篇
口腔科学   32篇
临床医学   137篇
内科学   232篇
皮肤病学   83篇
神经病学   16篇
特种医学   3篇
外科学   172篇
综合类   30篇
一般理论   1篇
预防医学   46篇
眼科学   8篇
药学   68篇
中国医学   23篇
肿瘤学   15篇
  2021年   4篇
  2020年   2篇
  2019年   6篇
  2018年   7篇
  2017年   16篇
  2016年   14篇
  2015年   30篇
  2014年   45篇
  2013年   48篇
  2012年   32篇
  2011年   23篇
  2010年   101篇
  2009年   123篇
  2008年   43篇
  2007年   34篇
  2006年   58篇
  2005年   22篇
  2004年   5篇
  2003年   13篇
  2002年   7篇
  2001年   3篇
  2000年   3篇
  1999年   9篇
  1998年   23篇
  1997年   46篇
  1996年   41篇
  1995年   28篇
  1994年   19篇
  1993年   19篇
  1992年   15篇
  1991年   16篇
  1990年   11篇
  1989年   10篇
  1988年   6篇
  1987年   13篇
  1986年   8篇
  1985年   2篇
  1984年   10篇
  1983年   7篇
  1981年   4篇
  1980年   2篇
  1979年   2篇
  1978年   2篇
  1975年   2篇
  1959年   9篇
  1958年   17篇
  1957年   9篇
  1956年   9篇
  1955年   2篇
  1954年   9篇
排序方式: 共有997条查询结果,搜索用时 31 毫秒
1.
2.
Percutaneous left atrial appendage (LAA) occlusion is a promising treatment option in patients with atrial fibrillation who have a high risk of embolic stroke and are not eligible for chronic oral anticoagulation therapy. This procedure, however, can induce several complications. Device embolization can result in a serious situation, requiring immediate and safe device removal. We report two cases in which dislodged LAA occlusion devices were flitting in the left atrium or entrapped in the mitral valve leaflets and were successfully retrieved through a transseptal approach without complications.  相似文献   
3.
Dual sensor ventricular demand rate responsive (VVIR mode) pacing was compared with single sensor rate responsive pacing to assess whether this new development should be more widely incorporated in modern pacemaker devices. A within patient randomized, double-blind crossover study involving ten patients, mean age 67.4 years (70% male), had Medtronic Legend Plus dual sensor VVIR pacemakers implanted for high grade A V block and chronic or persistent paroxysmal atrial fibrillation. Performance values were compared to 20 healthy control subjects of a similar age and gender. Patients were both subjectively and objectively assessed after 2 weeks of out-of-hospital activity in VVIR mode (minute ventilation sensing), VVIR mode (activity sensing), VVIR mode (dual sensor), and VVI mode (no rate response). All patients were assessed for subjective preference for, and objective improvement in, any pacing modality as assessed by standardized daily activity protocols and graded exercise treadmill testing. Subjective perception of exercise capacity and functional status was significantly lower in VVI mode (P < 0.05) compared to any of the VVIR modes, which did not differ. After completion of the study 70% of patients chose VVIR as their preferred mode, with 30% expressing no preference. Forty percent preferred activity sensor WIR mode pacing, 30% preferred dual sensor VVIR mode pacing, and 70% found either dual sensor WIR mode, minute ventilation sensor WIR mode, or both modalities least acceptable. No patient found activity sensing WIR mode least acceptable. Graded treadmill testing revealed significantly lower exercise tolerance during WI mode pacing (P < 0.01) compared to the VVIR modalities, which did not differ. Overall, chronotropic response was best with dual sensor pacing during standardized daily activity protocols and during the standard car journey. The data from this study suggest that there is no marked clinical advantage obtained from the use of dual sensor devices over current activity sensing ventricular demand rate responsive pacemakers, but with the probable added disadvantages of increased size, complexity, cost, and decreased longevity.  相似文献   
4.
The purpose of this study was to determine the feasibility and efficacy of bilateral decompression procedure via microscopic tubular crossing laminotomy (MTCL) for treating lumbar spinal stenosis (LSS). Seventeen patients with LSS underwent bilateral decompression via an MTCL procedure in which tubular retractor was placed. The mean age was 72 (range 59–84) years and there were 10 men and 7 women. All patients underwent pre- and postoperative dynamic lumbar x-ray, magnetic resonance (MR) image, and computed tomography. To verify the efficacy of this technique, pre- and postoperative cross-sectional area (CSA) of thecal sac, facet resection, and fatty infiltration (FI) of multifidus were measured. Clinical results were evaluated using Oswestry Disability Index (ODI), back and leg visual analog scale (VAS). The mean follow-up period was 17.5 months (range 12.1–21.2). 70.5% of MTCL was performed at the level of L4–5 and one case of dural violation (5.8%) was noted at the level of L5–S1. The mean preoperative CSA was 70.5 mm2 (range 25.1–87.6) and it increased to 198.8 mm2 (range 177.3–219.2) postoperatively (p = 0.00). The mean facet resection rate was 18.4% (range 9.9–26.9) and no radiological instability was noted postoperatively. MR image showed no increase in FI of the multifidus after 12 months of follow-up (p = 0.53). Preoperative clinical symptoms improved significantly at postoperative 6 months and 12 months of follow-up. These results indicate that an MTCL with use of tubular retractor system can be an effective procedure to achieve neural decompression for the treatment of LSS and it may be beneficial in preserving both facet joint and multifidus muscle.  相似文献   
5.
6.
7.
8.
Objectives: The aim of the present study was to determine whether administration of zolpidem, a nonbenzodiazepine sedative‐hypnotic agent, at night would improve the nocturia unresponsive to alpha‐blocker monotherapy in men with lower urinary tract symptoms (LUTS). Methods: This was a prospective observational study comprised of 39 men aged 50 years and older. The study inclusion criteria were age more than 50 years, and nocturia twice or more per night after taking alpha‐blockers for more than 8 weeks. A total of 39 patients met the criteria and constituted the study cohort. Pittsburgh Sleep Quality Index (PSQI), International Prostate Symptom Score (IPSS), frequency volume chart (FVCs) and uroflowmetry were recorded. Patients were given 10 mg alfuzosin and 10 mg zolpidem once at night for the 8 weeks. Results: There were no serious side‐effects in any patient. Nocturia decreased from a baseline (3.1 ± 0.1) to 8 weeks (1.6 ± 0.2) (P = 0.001). After treatment, global PSQI scores and severe sleep disorders improved. Storage and voiding symptoms including total IPSS scores and quality of life index improved. Nocturnal urine volume and functional bladder capacity improved. Maximum flow rate, voided volume increased and residual urine volume decreased. Conclusion: Combined zolpidem and alpha‐blocker therapy resulted in a subjective and objective reduction in nocturia episodes when given to men with nocturia unresponsive to alpha‐blocker monotherapy.  相似文献   
9.
1. The in vitro metabolism of the new insecticide flupyrazofos was studied using rat liver microsomes. Two metabolites were produced and identified as O, O -diethyl O -(1- phenyl-3-trifluoromethyl-5-pyrazoyl) phosphoric acid ester (flupyrazofos oxon) and 1- phenyl-3-trifluoromethyl-5-hydroxypyrazole (PTMHP) based on UV and mass spectral analysis. 2. Cytochrome P450 oxidatively converted flupyrazofos to flupyrazofos oxon, a major metabolite and phenobarbital-induced microsomes increased this desulphuration by 8- fold. 3. Flupyrazofos oxon was converted to PTMHP with a half-life of 47 8?min by chemical hydrolysis and this conversion also proceeded non-enzymatically under our microsomal incubation conditions.  相似文献   
10.
Aim: This study aimed to evaluate the immediate and long‐term effects of a 12 week problem‐solving (PS) counseling program to facilitate intensified walking with machinery monitoring on persons with type 2 diabetes mellitus in Korea. Methods: The study used a quasi‐experimental design. The participants were 57 patients with diabetes from three endocrinology or internal medicine clinics in an urban city of South Korea. Moderate‐intensity walking and PS counseling were recommended to both groups. The difference between the two groups was whether the intensity of the exercise was monitored by an ambulatory heart rate monitor (experimental group) or was self‐regulated (comparison group). Those programs were evaluated in relation to BMI, glycemic control (blood glucose level, glycosylated hemoglobin [HbA1c]), a vascular complication index (total cholesterol, high‐density lipoprotein cholesterol, low‐density lipoprotein cholesterol, triglycerides, tissue plasminogen activator [t‐PA], plasminogen activator inhibitor‐1 [PAI‐1], Parma Cardiovascular Risk Index), and coping strategies at 3 and 6 months. Results: The experimental group members showed dramatic decreases in their glucose and HbA1c levels at 3 months. The values of t‐PA decreased significantly at baseline, compared to at 3 months. The levels of PAI‐1 continuously declined and the Parma Cardiovascular Risk Index score did not change significantly from baseline to at 3 months, but showed significant effects at 6 months. Conclusion: A combined program of intensified walking, using a heart rate monitor, with PS counseling is more helpful to prevent complications than self‐regulated exercise for persons with type 2 diabetes in Korea.  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