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   579篇
  免费   20篇
  国内免费   14篇
耳鼻咽喉   9篇
儿科学   19篇
妇产科学   10篇
基础医学   41篇
口腔科学   35篇
临床医学   41篇
内科学   145篇
皮肤病学   26篇
神经病学   96篇
特种医学   14篇
外科学   86篇
综合类   12篇
预防医学   13篇
眼科学   27篇
药学   28篇
中国医学   1篇
肿瘤学   10篇
  2023年   4篇
  2022年   4篇
  2021年   8篇
  2020年   13篇
  2019年   12篇
  2018年   21篇
  2017年   22篇
  2016年   16篇
  2015年   30篇
  2014年   31篇
  2013年   27篇
  2012年   49篇
  2011年   36篇
  2010年   29篇
  2009年   24篇
  2008年   41篇
  2007年   42篇
  2006年   57篇
  2005年   35篇
  2004年   43篇
  2003年   19篇
  2002年   22篇
  2001年   5篇
  2000年   3篇
  1999年   3篇
  1997年   3篇
  1996年   1篇
  1994年   2篇
  1993年   1篇
  1991年   1篇
  1988年   1篇
  1977年   1篇
  1976年   2篇
  1970年   1篇
  1969年   1篇
  1967年   2篇
  1966年   1篇
排序方式: 共有613条查询结果,搜索用时 984 毫秒
11.
12.
Pituitary - Although it is well known that acromegaly causes enlargement in the extremities, studies investigating the effects of acromegaly on tendons, muscles and soft tissue are limited. The...  相似文献   
13.
Melatonin is synthesized and released by the pineal gland in a circadian rhythm, and many of its peripheral actions are mediated via membrane MT1 and MT2 receptors. Apart from its metabolic functions, melatonin is a potent neuroprotective molecule owing to its antioxidative actions. The roles of MT1 and MT2 in the neuroprotective effects of melatonin and cell signaling after cerebral ischemia remain unknown. With the use of MT1 and MT2 knockout (mt1/2(-/-) ) mice treated with melatonin, we evaluated brain injury, edema formation, inducible nitric oxide synthase (iNOS) activity, and signaling pathways, including CREB, ATF-1, p21, Jun kinase (JNK)1/2, p38 phosphorylation, resulting from ischemia/reperfusion injury. We show that the infarct volume and brain edema do not differ between mt1/2(-/-) and wild-type (WT) animals, but melatonin treatment decreases infarct volume in both groups and brain edema in WT animals after middle cerebral artery occlusion. Notably, melatonin's neuroprotective effect was even more pronounced in mt1/2(-/-) animals compared to that in WT animals. We also demonstrate that melatonin treatment decreased CREB, ATF-1, and p38 phosphorylation in both mt1/2(-/-) and WT mice, while p21 and JNK1/2 were reduced only in melatonin-treated WT animals in the ischemic hemisphere. Furthermore, melatonin treatment lowered iNOS activity only in WT animals. We provide evidence that the absence of MT1 and MT2 has no unfavorable effect on ischemic brain injury. In addition, the neuroprotective effects of melatonin appear to be mediated through a mechanism independent of its membrane receptors. The underlying mechanism(s) should be further studied using selective melatonin receptor agonists and antagonists.  相似文献   
14.

Introduction

Near-infrared diode lasers can be used for several applications, which range from disinfection to smear layer removal in endodontics. This study evaluated the efficacy of agitation of 15% EDTA with an 808-nm diode laser on removal of the smear layer.

Methods

Sixty extracted human maxillary central incisor teeth were instrumented up to ProTaper F4 (Dentsply Maillefer, Ballagues, Switzerland) and then randomly divided into 6 groups (n = 10 for each group) according to the different final irrigating protocols as follows: 5% sodium hypochlorite for 120 seconds performed with the NaviTip (Dentsply Maillefer, Ballaigues, Switzerland) (control group); 15% EDTA for 120 seconds performed with the NaviTip; and agitation of 15% EDTA with an 808-nm diode laser for 10, 20, 30, and 40 seconds. Specimens were observed under a scanning electron microscope, and open dentinal tubules were counted using Adobe Photoshop software (Adobe Systems, San Jose, CA). The data were analyzed with 1-way analysis of variance and Tukey post hoc tests (P = .05).

Results

The number of open dentinal tubules was higher in the middle thirds than in the apical thirds. The differences between the apical and middle thirds were statistically significant (P < .05). Statistically significant differences were also found between the control group and the other groups in both the middle and apical thirds of the root canals (P < .05).

Conclusions

The results indicated that agitation of 15% EDTA with an 808-nm diode laser for 20 seconds was effective in removing the smear layer in the apical thirds of root canals.  相似文献   
15.
Objectives Although development of new treatment modalities limited digoxin usage, digoxin intoxication is still an important issue which could be easily overlooked. In this report we analyzed a case series definitively diagnosed as digoxin intoxication in the modern era. Methods We analyzed 71 patients hospitalized with digoxin intoxication confirmed by history, complaints, clinical and electrocardiograph (ECG) findings, and serum digoxin levels > 2.0 ng/mL, during a five year period. The demographic and clinical data, indications for digoxin use, digoxin dosage, concurrent medications, laboratory data, hospital monitoring, and ECG findings were obtained from all patients. Results Thirty-eight of 71 patients (53.5%) had symptoms of heart failure during admission or later. Sixty-four percent of patients were older than 75 years. The percentage of females was 67%. Atrial fibrillation, hypertension and gastrointestinal complaints were more frequent in the females (64% in females, 30% in males, P = 0.007; 81% in female, 52% in males, P = 0.01; 50% in female, 17.3% in males, P = 0.008, respectively). The mortality rate during the hospital course was 7%. Conclusion This report demonstrated the reduced mortality rates in patients with digoxin intoxication over the study period. Gastrointestinal complaints are the most common symptoms in this population.  相似文献   
16.

Objective

To determine the prognostic value of pT3 bladder urothelial carcinoma substaging in patients without lymphatic involvement.

Patients and methods

Pathologic and clinical data were reviewed on patients who underwent radical cystectomy for urothelial carcinoma between 1991 and 2010. Of the 460 reviewed patients, 74 patients were diagnosed with pathologic T3No urothelial carcinoma of the bladder. The impact of pathologic substaging (pT3a vs. pT3b) was examined to determine the effect on overall and disease-specific survival.

Results

Five years disease-specific and overall survival rates were 46.9 % and 39.6 % for patients with pT3aNo tumor, whereas these ratios were 34.4 and 30.3 %, respectively, for patients with pT3bNo tumor (p > 0.05). Mean disease-specific survival time was 43.94 ± 6.50 months for pT3aNo, while it was 39.01 ± 7.19 months for pT3bNo (p = 0.539). In multivariate cox regression analysis, age (p = 0.459), gender (p = 0.710), urinary diversion type (p = 0.088), and pT3 substaging (p = 0.554) were not noticed as an independent predictive factor for survival.

Conclusion

Macroscopic extravesical extension (pT3b) is not associated with a worse outcome than pT3a disease in lymph node-negative cases of bladder urothelial carcinoma.  相似文献   
17.
18.
Objectives. Vitamin D regulates calcium and bone homeostasis, and parathyroid hormone (PTH) secretion. Cross-sectional associations between lower vitamin D levels and cardiovascular diseases have been reported, but the relationship between vitamin D levels and collateral arteries in stable coronary artery disease (CAD) has not been reported before. Design. Two hundred and fourteen patients with above 95% stenosis in at least one epicardial coronary artery were consecutively recruited after coronary angiography (CAG) during the winter season. The coronary collateral circulation (CCC) was graded using Rentrop classification. Poor CCC group included patients with Rentrop Grade 0–1 CCC and control group included patients with Rentrop Grade 2–3 CCC. Vitamin D and PTH levels were measured on the day of CAG. Results. In the poor CCC group, vitamin D levels were lower (34 ± 25 pmol/L vs. 49 ± 33 pmol/L; p = 0.01) and the prevalence of vitamin D deficiency (< 37 pmol/L) was higher (67% vs. 43%; p = 0.01) compared to the controls. PTH levels, calcium, and phosphate levels were not significantly different between the groups. Female gender, lower HDL cholesterol, and lower vitamin D levels were independently correlated with poor CCC in the study population. Conclusion. Lower vitamin D levels may be associated with poor collateral development in patients with stable CAD.  相似文献   
19.
20.
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