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   989篇
  免费   54篇
  国内免费   9篇
耳鼻咽喉   20篇
儿科学   42篇
妇产科学   45篇
基础医学   74篇
口腔科学   96篇
临床医学   74篇
内科学   223篇
皮肤病学   4篇
神经病学   50篇
特种医学   47篇
外科学   269篇
综合类   15篇
预防医学   14篇
眼科学   12篇
药学   45篇
中国医学   3篇
肿瘤学   19篇
  2024年   3篇
  2023年   10篇
  2022年   25篇
  2021年   36篇
  2020年   22篇
  2019年   25篇
  2018年   27篇
  2017年   32篇
  2016年   40篇
  2015年   55篇
  2014年   60篇
  2013年   60篇
  2012年   119篇
  2011年   92篇
  2010年   42篇
  2009年   45篇
  2008年   85篇
  2007年   75篇
  2006年   60篇
  2005年   53篇
  2004年   37篇
  2003年   26篇
  2002年   18篇
  2001年   2篇
  1999年   2篇
  1996年   1篇
排序方式: 共有1052条查询结果,搜索用时 15 毫秒
21.
The discovery of functional organic–inorganic hybrid nanoflowers (FNFs) consisting of proteins/enzymes as the organic components and Cu(ii) ion as the inorganic component has made an enormous impact on enzyme immobilization studies. The FNFs synthesized by an encouraging and novel approach not only showed high stabilities but also much enhanced catalytic activities as compared to free and conventionally immobilized enzymes. A recent development demonstrated that FNF formation has moved beyond the initial discovery in which enzymes and Cu2+ ions used as the organic and inorganic parts, respectively, are replaced with new organic (chitosan, amino acid and plant extracts) and inorganic (Cu2+ and Fe2+) materials. The new organic materials incorporated into FNFs act as Fenton-like agents and then show peroxidase-like activity owing to the metal ions and the porous structure of FNFs in the presence of hydrogen peroxide (H2O2). All FNFs have been widely utilized in many different scientific and industrial fields due to their greatly enhanced activities and stabilities. This review focuses primarily on the preparation, characterization, and bioanalytical applications of FNFs and explains the mechanisms of their formation and enhanced activities and stabilities.

The discovery of functional organic–inorganic hybrid nanoflowers (FNFs) consisting of proteins/enzymes as the organic components and Cu(ii) ion as the inorganic component has made an enormous impact on enzyme immobilization studies.  相似文献   
22.
To verify whether low-dose aprotinin reduces blood loss and blood product usage in patients with clopidogrel exposure within 5 days before off-pump coronary artery bypass, 51 patients with clopidogrel exposure were randomized in a double-blind fashion to receive low-dose aprotinin (25 patients), or placebo (26 patients). The baseline characteristics and number of distal anastomoses in the patients in each group were comparable. Time between the last dose of clopidogrel and start of the operation was similar in both groups, as was mean left ventricular ejection fraction. Chest tube drainage, blood product usage, and reoperation rate were significantly higher in the placebo group. In patients with unstable angina and recent clopidogrel exposure who are undergoing off-pump coronary artery bypass, intraoperative administration of low-dose aprotinin is recommended to reduce blood loss and transfusion requirements.  相似文献   
23.
IntroductionStudies have shown that sarcopenia is associated with poor outcomes in patients with gastrointestinal cancer undergoing surgery. We aimed to investigate the relationship between postoperative complications of sarcopenic patients who had been operated on for colon cancer and the effects on short-term mortality.Material and methodsIn this study, patients who had undergone colon cancer surgery between January 2013 and December 2018 were collected retrospectively. Sarcopenia was diagnosed by the skeletal muscle index (SMI) derived from a preoperative computed tomography scan. Multiple logistic regression analysis was performed to determine whether sarcopenia is associated with postoperative major complications (POMC).ResultsThe study included 160 patients with a mean age of 62.4 ±12.6 years. Clavien-Dindo grade 1–2 (minor) complications were not significantly different between the groups (p = 0.896). However, grade ≥ 3 (major) complications were detected in 13 (17.8%) patients in the sarcopenic group (SG) and in 5 patients in the non-sarcopenic group (NSG) (5.7%) (p = 0.016). Length of intensive care unit (ICU) stay was longer in SG (p = 0.002) and there was no difference between 1-month and 6-month mortality rates (p = 0.273 and p = 0.402, respectively). According to univariate analyses, sarcopenia and age over 65 years were related to POMC. In multivariate analyses, sarcopenia (odds ratio = 3.039; 95% confidence interval 1.008–9.174; p = 0.048) and advanced age (odds ratio = 3.246; 95% confidence interval 1.078–9.803; p = 0.036) were found to be independent risk factors for POMC.ConclusionsThis study showed that while sarcopenia is a risk factor for POMC, sarcopenia also prolongs the duration of ICU stay. Also sarcopenia has no effect on short-term mortality.  相似文献   
24.

OBJECTIVE

In the post-sternotomy mediastinitis patients, Staphylococcus aureus is the pathogenic microorganism encountered most often. In our study, we aimed to determine the efficacy of antibiotic treatment with vancomycin and tigecycline, alone or in combination with hyperbaric oxygen treatment, on bacterial elimination in experimental S. aureus mediastinitis.

METHODS

Forty-nine adult female Wistar rats were used. They were randomly divided into seven groups, as follows: non-contaminated, contaminated control, vancomycin, tigecycline, hyperbaric oxygen, hyperbaric oxygen + vancomycin and hyperbaric oxygen + tigecycline. The vancomycin rat group received 10 mg/kg/day of vancomycin twice a day through intramuscular injection. The tigecycline group rats received 7 mg/kg/day of tigecycline twice a day through intraperitoneal injection. The hyperbaric oxygen group underwent 90 min sessions of 100% oxygen at 2.5 atm pressure. Treatment continued for 7 days. Twelve hours after the end of treatment, tissue samples were obtained from the upper part of the sternum for bacterial count assessment.

RESULTS

When the quantitative bacterial counts of the untreated contaminated group were compared with those of the treated groups, a significant decrease was observed. However, comparing the antibiotic groups with the same antibiotic combined with hyperbaric oxygen, there was a significant reduction in microorganisms identified (P<0.05). Comparing hyperbaric oxygen used alone with the vancomycin and tigecycline groups, it was seen that the effect was not significant (P<0.05).

CONCLUSION

We believe that the combination of hyperbaric oxygen with antibiotics had a significant effect on mediastinitis resulting from methicillin-resistant Staphylococcus aureus. Methicillin-resistant Staphylococcus aureus mediastinitis can be treated without requiring a multidrug combination, thereby reducing the medication dose and concomitantly decreasing the side effects.  相似文献   
25.
26.
The supraclavicular fasciocutaneous flap is a well‐recognized flap in head and neck reconstruction. In this report, we describe for the first time a variation of this flap, the osteocutaneous supraclavicular (SOC) free flap, which was used to reconstruct a composite nasal defect. The defect arose after resection of a recurrent squamous cell carcinoma and involved dorsal nasal skin, cartilage, and the entire nasal bone. A 6 cm × 4 cm size flap including skin, subcutaneous tissue, and a vascularized cortico‐periosteal segment of the clavicle was raised based on the transverse cervical artery. The flap survived with no complications. A satisfactory aesthetic outcome was achieved following two revision procedures. We believe that the incorporation of bone to the supraclavicular flap may expand its applications in reconstruction of composite nasal and facial defects. © 2015 Wiley Periodicals, Inc. Microsurgery 35:328–332, 2015.  相似文献   
27.
28.
29.

Objectives

The present study aims to specify the role of l-carnitine in the pathogenesis of endometrial cancer by comparing the serum total l-carnitine levels of endometrial cancer patients with those of healthy women.

Methods

Serum total l-carnitine concentrations were measured in patients with endometrioid-type endometrial cancer (n = 20) and healthy controls (n = 20) who were matched with respect to age and body mass index (BMI).

Results

Stage I endometrial cancer was diagnosed in 12 women (60.0 %) whereas three women (15.0 %) had stage II disease, three women (15.0 %) had stage III disease and two women (10.0 %) had stage IV disease. The healthy controls and endometrial cancer patients were statistically similar in aspect of age, gravidity, parity, BMI, waist-to-thigh ratio, waist-to-hip ratio, menopause, complete blood count parameters, and serum biochemistry. Serum total l-carnitine levels of women with endometrial cancer were significantly lower than those of healthy women (respectively, 5,519.4 ± 2,712.5 vs 7,940.8 ± 3,566.6 ng/dl, p = 0.021). Moreover, serum total l-carnitine levels decreased significantly and progressively with advancing stage (stage I vs II vs III vs IV; 6,294.0 ± 2,885.1 vs 5,800.0 ± 441.2 vs 4,016.0 ± 2,833.3 vs 2,560.0 ± 67.9 ng/dl; p = 0.021).

Conclusions

This is the first study to hypothesize that l-carnitine deficiency participates in the pathogenesis of endometrial cancer by means of a mechanism which is unrelated with obesity and increased amount of fat in human body.
  相似文献   
30.
AIM: To investigate the roles of the adipocytokines, ghrelin and leptin in gastric cancer cachexia.
METHODS: Resistin, ghrelin, leptin, adiponectin, insulin and insulin-like growth factor (IGF-Ⅰ), were measured in 30 healthy subjects, and 60 gastric cancer patients of which 30 suffered from cancerinduced cachexia and 30 served as a control group. The relationships between hormones, body mass index (BMI) loss ratio, age, gender, and Glasgow Prognostic Score (GPS) were investigated.
RESULTS: Cachexia patients had higher tumor stage and GPS when compared with non-cachexia patients (P 〈 0.05). Ghrelin, resistin, leptin, adiponectin and IGF- Ⅰ, showed a significant correlation with BMI loss ratio and GPS (P 〈 0.05). A strong correlation was seen between GPS and BMI loss (R = -0.570, P 〈 0.0001). Multivariate analysis indicated that BMI loss was significantly independent as a predictor of ghrelin, resistin, leptin and IGF-Ⅰ (P 〈 0.05). Existence of an important significant relationship between resistin and insulin resistance was also noted.
CONCLUSION: These results showed that serum ghrelin, leptin, adiponectin, and IGF-Ⅰ play important roles in cachexia-related gastric cancers. No relationship was found between resistin and cancer cachexia. Also, because of the correlation between these parameters and GPS, these parameters might be used as a predictor factor.  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