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   1256篇
  免费   56篇
  国内免费   11篇
耳鼻咽喉   47篇
儿科学   80篇
妇产科学   69篇
基础医学   95篇
口腔科学   33篇
临床医学   106篇
内科学   266篇
皮肤病学   36篇
神经病学   57篇
特种医学   41篇
外科学   265篇
综合类   18篇
一般理论   1篇
预防医学   33篇
眼科学   73篇
药学   55篇
中国医学   3篇
肿瘤学   45篇
  2023年   4篇
  2022年   19篇
  2021年   25篇
  2020年   21篇
  2019年   29篇
  2018年   35篇
  2017年   27篇
  2016年   40篇
  2015年   47篇
  2014年   74篇
  2013年   75篇
  2012年   115篇
  2011年   95篇
  2010年   56篇
  2009年   38篇
  2008年   62篇
  2007年   83篇
  2006年   71篇
  2005年   100篇
  2004年   87篇
  2003年   89篇
  2002年   50篇
  2001年   13篇
  2000年   13篇
  1999年   10篇
  1998年   7篇
  1997年   6篇
  1996年   5篇
  1995年   3篇
  1994年   3篇
  1993年   4篇
  1992年   2篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1972年   2篇
  1971年   1篇
  1970年   1篇
  1967年   1篇
  1966年   1篇
  1959年   1篇
排序方式: 共有1323条查询结果,搜索用时 15 毫秒
991.

Background  

Several modifications to an esophageal replacement approach have been described, using the left, the right, or the transverse colon as an interposition flap. Interposition of the left colon has become the most popular procedure. Intraoperative clamping of the arterial blood supply and venous drainage of the flap is a possible reason for ischemic flap failure. Thus, we designed a novel model to investigate whether erythropoietin (EPO), which has a tissue-protective effect in ischemia, would have any protective effect on prepared colon flaps in rats.  相似文献   
992.
We determined serum levels of ascorbic acid, betacarotene, retinol and alpha tocopherol and lipid peroxidation (as estimated by thiobarbituric acid reacting substances (TBARS) generation) in 24 multiple sclerosis (MS) patients and 24 healthy sex- and age-matched person as control. The levels of four antioxidant vitamins were significantly lower in MS patients compared to controls (p < 0.05). TBARS levels were significantly higher in the patients of MS compared to the controls (p = 0.001). In MS patients, the levels of beta-carotene, alpha tocopherol and ascorbic acid correlated significantly with each other (r2 = 0.689 - 0.779). It appeared that there was inverse correlation between the serum levels of ascorbic acid or beta-carotene, but not of alpha tocopherol or retinol, and TBARS levels in MS. The present study indicates that antioxidant vitamins (alpha tocopherol, beta-carotene, retinol and ascorbic acid) are decreased in sera of MS patients during an attack, and that this decrease may well be dependent on the increased oxidative burden as reflected by lipid peroxidation products. The role of antioxidant vitamin supplementation in prevention and/or treatment of MS remains to be explored.  相似文献   
993.
BackgroundLaparoscopic sleeve gastrectomy (LSG) is a frequently performed operation. Leaks are formidable complications; however, the optimal management of these leaks is controversial.MethodsWe retrospectively reviewed the medical records of 15 patients referred to our tertiary center between 2012 and 2016 with leaks after LSG.ResultsIn 12 patients with whom ongoing leaks were identified, stents were inserted with the intent of definitive therapy. In addition to attempts at source control, percutaneous drainage was carried out for intraabdominal collection in 9 patients and pleural effusion in 4 patients. The length of stay in the intensive care unit was significantly shorter in patients referred earlier or in those without any intervention.ConclusionLSG leaks can be treated nonoperatively in well-organized centers under meticulously designed protocols, depending on the clinical condition of the patient.  相似文献   
994.
995.
996.
997.
Polycystic ovary syndrome (PCOS) is a heterogeneous disorder, which is considered not only a reproductive disease but also a metabolic disorder associated with long-term health risks. The aim of this study was to assess the effects of metformin on insulin resistance, oxidant–antioxidant status, endothelial dysfunction, lipid metabolism and their contribution to the risks of cardiovascular disease in women with PCOS. Fifteen women with PCOS and 17 healthy women were included in this case–control study. Nitric oxide (NO), endothelin-1 (ET-1), malondialdehyde (MDA), Apo A1, Apo B, small, dense LDL cholesterol (sdLDL-C), lipid levels and paraoxonase 1 (PON1) activity were measured in serum/plasma obtained from study groups. Insulin resistance (HOMA index – Homeostasis Model Assessment) and serum sex hormone profiles were also evaluated. Significantly decreased NO levels and PON1 activities, but increased MDA, ET-1 and sdLDL-C were found in PCOS patients compared to those of controls. Serum MDA, ET-1, HOMA and sdLDL-C levels decreased and PON1 activity and NO levels increased significantly after the metformin treatment. There was a positive correlation between MDA and free testosterone (fT), ET-1 and fT; and a negative correlation between PON1 activity and fT. Insulin resistance, dyslipidemia, endothelial dysfunction and oxidative stress might contribute to the excess risk of cardiovascular disease reported in PCOS. Metformin seemed to decrease oxidative stress and improve insulin resistance, dyslipidemia and endothelial dysfunction in PCOS patients.  相似文献   
998.
999.
PURPOSE: When standard aortofemoral surgical procedure is combined with lower extremity vascular surgery, problems related with the hospital stay, morbidity, mortality and the cost of treatment will exist. The number of reports relating to combined iliac artery PTA and distal bypass surgery is limited. After the development of stenting procedures, the results of arterial system plasty have much more improved. This report reviews our preliminary experience with iliac artery angioplasty with distal bypass procedures. PATIENTS AND METHODS: A total of 41 patients have undergone combined iliac artery dilatation and distal arterial revascularization. Angioplastic procedures were performed in the angiography suite and distal surgery was carried out at the same day or the day after. Of all patients, 29 underwent percutaneous transluminal angioplasty (PTA) and 12 underwent combined PTA and stent placement. Ipsilateral femoropopliteal bypass was performed as a distal revascularization procedure in all patients. RESULTS: Mean systolic iliac artery pressure gradients improved from 34.7+/-8.6 mmHg to 3.9+/-3.2 mmHg after angioplastic procedures (P < 0.0001). Six patients needed reangioplasty because of restenosis in the follow-up period. Thrombectomy was performed on 1 patient in the early postoperative period and re-do femoropopliteal bypass was performed on two patients in the 2nd and 23rd months. Three minor wound infections were successfully treated with antibiotics and local care. Mean follow-up was 21.4 months (range 1-48 months).By life-table analyses, the overall 4-year cumulative primary patency of combined procedures was 78.1%. CONCLUSION: The results show that the combined procedure is a suitable method for the treatment of patients with multiple stenotic lesions at the iliac and distal arterial levels. We believe that the combined use of PTA and distal vascular surgery by an experienced surgical team will give beneficial results and a highly satisfactory outcome in this group of patients.  相似文献   
1000.

Background

Recently, we demonstrated better perioperative outcomes with robotic versus laparoscopic adrenalectomy (LA) with the posterior retroperitoneal approach in general, and for removal of large adrenal tumors. It is unknown if robotic adrenalectomy (RA) is equivalent to LA in obese patients. The aim of this study is to compare perioperative outcomes of RA versus LA in obese patients.

Methods

Between 2003 and 2012, 99 obese (BMI ≥ 30 kg/m2) patients underwent adrenalectomy at a tertiary academic center. Of these, 42 patients had RA and 57 had LA. The perioperative outcomes of these patients were compared between the RA and LA groups. Data were collected from a prospectively maintained, institutional review board approved database. Clinical and perioperative parameters were analyzed using Student t and χ2 tests. All data are expressed as mean ± standard error of the mean.

Results

The groups were similar in terms of age, gender, and tumor side. Body mass index was lower in the robotic versus laparoscopic group (35.4 ± 1.0 vs. 38.8 ± 0.8 kg/m2, respectively, p = 0.01). Tumor size (4.0 ± 0.4 vs. 4.3 ± 0.3 cm, respectively, p = 0.56), skin-to-skin operative time (186.1 ± 12.1 vs. 187.3 ± 11 min, respectively, p = 0.94), estimated blood loss (50.3 ± 24.3 vs. 76.6 ± 21.3 ml, respectively, p = 0.42), and hospital stay (1.3 ± 0.1 vs. 1.6 ± 0.1 days, respectively, p = 0.06) were similar in both groups. The conversion to open rate was zero in the robotic and 5.2 % in the laparoscopic group (p = 0.06). The 30-day morbidity was 4.8 % in the robotic and 7 % in the laparoscopic group (p = 0.63).

Conclusions

Our study did not show any difference in perioperative outcomes between RA and LA in obese patients. These results suggest that the difficulties in maintaining exposure and dissection in obese patients nullify the advantages of robotic articulating versus rigid laparoscopic instruments in adrenal surgery.  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