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   389篇
  免费   18篇
  2023年   10篇
  2022年   7篇
  2021年   18篇
  2020年   18篇
  2019年   14篇
  2018年   15篇
  2017年   19篇
  2016年   16篇
  2015年   16篇
  2014年   21篇
  2013年   32篇
  2012年   25篇
  2011年   26篇
  2010年   29篇
  2009年   14篇
  2008年   16篇
  2007年   28篇
  2006年   19篇
  2005年   16篇
  2004年   10篇
  2003年   13篇
  2002年   11篇
  2001年   2篇
  1999年   2篇
  1998年   2篇
  1997年   2篇
  1992年   1篇
  1991年   2篇
  1987年   1篇
  1981年   1篇
  1975年   1篇
排序方式: 共有407条查询结果,搜索用时 15 毫秒
91.
92.
High recurrence and metastatic behavior patterns are the most important reasons for the failure of treatment strategies in patients with colon cancer. Cancer stem cells (CSCs), which are considered root of cancer, are thought to be associated with therapy resistance, relapse, and metastasis, and, therefore, targeting CSCs rather than the bulk population may be an effective approach. In cancer studies, there is an increasing interest in close friendship between epithelial-mesenchymal transition (EMT) and CSCs. Triptolide (TPL) isolated from Chinese herb Tripterygium wilfordii has important effects on the prevention of migration and metastasis as well as cytotoxic effect against cancer cells. The potential lethal efficacy of TPL on CSCs that is highly resistant to the drug is an unsolved mystery. Fundamentally, the present study basically aims to find answers to two questions: (a) is it possible to target colon CSCs with TPL? and (b) what are the mechanisms underlying TPL's potential to eliminate CSCs? Cytotoxic effects of TPL on CSCs were evaluated by WST-1 and Muse count and viability assays. Apoptosis assay and cell-cycle analysis were performed to investigate the inhibitory effect of TPL. Moreover, the effects of TPL on spheroid formation capacity, migration, and EMT processes, which are associated with CSC phenotype, were also investigated. The results revealed that TPL triggered cell death and apoptosis and altered cell cycle distribution. Moreover, TPL significantly reduced the snail slug and twist expressions associated with EMT. TPL has been shown to be effective in colon CSCs by in vitro experiments, and it might be a highly effective agent against colon cancer has been implicated in need of supporting in vivo and clinical studies.  相似文献   
93.
The aim of this study was to develop chitosan film containing fucoidan and to investigate its suitability for the treatment of dermal burns on rabbits. Porous films, thickness between 29.7 and 269.0 μm, were obtained by the solvent dropping method. Water vapor permeability (3.3–16.6/0.1 g), the swelling (0.67–1.77 g/g), tensile strength (7.1–45.8 N), and bioadhesion (0.076–1.771 mJ/cm2) of the films were determined. The thinnest films were obtained with the lowest chitosan concentration (P<.05). The water absorption capacity of the films sharply increased with the freeze-drying technique. The film having the thickness of 29.7 μm showed the highest amount of moisture permeability (16.6 g/0.1 g). Higher chitosan concentration significantly increased tensile strength of the films (P<.05). Using higher concentration of lactic acid made films more elastic and applicable, and these films were selected for in vivo studies. Seven adult male New Zealand white rabbits were used for the evaluation of the films on superficial dermal burns. Biopsy samples were taken at 7, 14, and 21 days after wounding, and each wound site was examined macroscopically and histopathologically. After 7 days treatment, fibroplasia and scar were observed on wounds treated with fucoidan-chitosan film. The best regenerated dermal papillary formation, best reepithelization, and the fastest closure of wounds were found in the fucoidan-chitosan film treatment group after 14 days compared with other treatment and control groups. It can be concluded that fucoidan-chitosan films might be a potential treatment system for dermal burns and that changing formulation variables can modulate the characterizations of the films. Published: May 24, 2007  相似文献   
94.
Methotrexate (MTX), a folic acid antagonist, is widely used as a cytotoxic chemotherapeutic agent. MTX-associated neurotoxicity is an important clinical problem. The aim of this study was to investigate the role of caffeic acid phenethyl ester (CAPE) on cerebellar oxidative stress induced by MTX in rats. A total of 19 adult male rats were divided into three experimental groups as follows: MTX group (MTX treated), MTX+CAPE group (MTX+CAPE treated), and control group. MTX was administered intraperitoneally (i.p.) with a single dose of 20 mg kg−1 on the second day of experiment. CAPE was administered i.p. with a dose of 10 μmol kg−1 day−1 for 7 days. Malondialdehyde (MDA) levels and activities of superoxide dismutase (SOD) and catalase (CAT) were determined in cerebellar tissue of rats. MTX caused to significant increase in MDA levels (an important marker of lipid peroxidation) in the MTX group compared with the controls (p = 0.006). CAPE significantly reduced the MTX induced lipid peroxidation in the MTX+CAPE group compared to the MTX (p = 0.007). The activities of SOD and CAT were significantly increased in the MTX group when compared with the control group (p = 0.0001, p = 0.004, respectively). The increased activities of these enzymes were significantly reduced by CAPE treatment (p = 0.004, p = 0.034, respectively). As a result, CAPE may protect from oxidative damage caused by MTX treatment in rat cerebellum.  相似文献   
95.
Surgery induces release of neuroendocrine hormones (cortisol), cytokines (interleukin-6: IL-6, tumour necrosis factor-alpha: TNF-alpha), acute phase proteins (C-reactive protein: CRP, leptin). We studied the effects of general and spinal anaesthesia on stress response to haemorrhoidectomy. Patients were assigned to general and spinal anaesthesia groups (n = 7). Blood samples were drawn before induction and 24 hours after surgery. Perioperative levels of IL-6, TNF-alpha, CRP, cortisol, and leptin were comparable among the groups. Twenty four hours after surgery, TNF-alpha and cortisol did not change; IL-6 and CRP increased significantly in all patients. Significant increase in leptin levels was found in patients undergoing spinal anaesthesia. Except for the increase in leptin levels, there was no significant difference related to the effects of general and spinal anaesthesia.  相似文献   
96.

Background

We have previously described a RAF oncogene driven transgenic mouse model for non small cell lung cancer (NSCLC). Here we examine whether tumor initiation and growth requires the stem cell self-renewal factor Bmi1.

Principal Findings

In order to evaluate Bmi1 function in NSCLC two founder lines that differ in incidence and latency of tumor formation were compared. Ablation of Bmi1 expression in both lines had a dramatically decreased tumor growth. As the line with shorter latency matched the life span of Bmi1 knock out mice, these mice were chosen for further study. The absence of Bmi1 did not decrease the number of tumor initiation in these mice as only the size and not the number of tumors decreased. Reduction in tumor growth resulted from an increase in cell death and decrease in cell cycle progression that corresponded with up-regulation of the p16INK4a and p19ARF.

Significance

The data identifies Bmi1 as an important factor for expansion but not initiation of RAF driven NSCLC.  相似文献   
97.
Aim: This study aims to assess the antioxidant property of vitamins E and C in Helicobacter pylori infection, and to determine if adding them to standard triple therapy plus bismuth subcitrate increases the H. pylori eradication rate. Methods: This study included 160 patients infected with H. pylori, who were randomized into one of two groups. Patients in group A (n = 80) received lansoprazole (30 mg, b.i.d.), amoxicillin (1000 mg, b.i.d.), clarithromycin (500 mg, b.i.d.), and bismuth subcitrate (300 mg, q.i.d.) for 14 days, while patients in group B (n = 80) received vitamin C (500 mg, b.i.d.) and vitamin E (200 IU, b.i.d.) for 30 days, in addition to lansoprazole (30 mg, b.i.d.), amoxicillin (1000 mg, b.i.d.), clarithromycin (500 mg, b.i.d.), and bismuth subcitrate (300 mg, q.i.d.) for 14 days. Total antioxidant capacity (TAC) was evaluated with a Randox kit. Success rate was calculated using both intention‐to‐treat (ITT) and per‐protocol (PP) analyses. Results: One hundred and sixty patients were analyzed using ITT analysis. One hundred and fifty‐three patients completed the study. In group A, H. pylori eradication was achieved in 48 (60%) of the 80 patients included in the ITT analysis, and in 48 (64%) of the 75 patients included in the PP analysis. In group B, H. pylori eradication was achieved in 73 (91.25%) of the 80 included in the ITT analysis and in 73 (93.5%) of the 78 patients included in the PP analysis. The eradication rate was significantly higher in group B than in group A (p < .005). TAC was at the lower limit of normal in both groups and the difference between them was not statistically significant (p > .05). Conclusion: In group B, H. pylori eradication rate was 91.25%, which is higher than the ideal 80% eradication rate. The results of the present study show that adding the prescribed doses of vitamins E and C to antimicrobial therapy is effective in eradicating H. pylori infection.  相似文献   
98.
Tricholoma matsutake produces commercially valuable, yet uncultivable, mushrooms (matsutake) in association with pines in the Far East and Scandinavia and with both pines and oaks in the foothills of Tibet. Other matsutake mushrooms, such as Tricholoma anatolicum from the Mediterranean regions and Tricholoma magnivelare and Tricholoma sp. from the North Pacific Coast area of Canada and North America as well as Mexico, respectively, are associated with pines or oaks in their natural habitats. Tricholoma bakamatsutake and Tricholoma fulvocastaneum from Asia produce moderately valuable matsutake mushrooms and are solely associated with Fagaceae in nature. In this study, we demonstrate for the first time that matsutake mushrooms from Scandinavia, Mediterranean regions, North America, and Tibet form ectomycorrhizae with Pinus densiflora similar to the Far East T. matsutake. In general, worldwide T. matsutake and the symbionts of Pinaceae colonize the rhizospheres of P. densiflora as well as T. matsutake isolated from the host plant. However, T. fulvocastaneum and T. bakamatsutake formed a discontinuous Hartig net and no Hartig net, respectively, and colonized to a lesser extent as compared to T. matsutake. The data suggest that conifer-associated matsutake mushrooms in their native habitat will associate symbiotically with the Asian red pine.  相似文献   
99.
The therapeutic effects of poly(adenosine diphosphate-ribose) polymerase inhibition by 3-aminobenzamide (3-AB) were investigated in testicular ischemia-reperfusion (I/R) injury, using sperm analysis and histopathological and biochemical examinations, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities and reduced glutathione (GSH) levels. Male rats were divided into 3 groups: sham (n = 12), I/R (n = 12), and I/R with 3-AB (I/R-3-AB) (n = 12). The left testicular artery was occluded for 1 h, followed by 24 h (for biochemical and histopathological examinations) and 30 days (for sperm analysis) of reperfusion. 3-AB treatment intraperitoneally 10 min prior to and 1 h after reperfusion increased the I/R-induced decrease in sperm motility in both testes and reduced the increased abnormal sperm rates in the ipsilateral testis. However, 3-AB treatment failed to prevent the I/R-induced decrease in sperm concentration in both testes. SOD and CAT activities did not change in any group. GSH-Px activity and GSH levels were increased by I/R. 3-AB treatment reversed the I/R-induced increase in GSH-Px activity, similar to the level in sham rats, but did not alter GSH levels. 3-AB treatment significantly increased the I/R-induced decrease in histopathologic score. In conclusion, 3-AB treatment has potential biochemical and histopathological benefits beyond improving sperm quality and may have the potential to decrease damage from testicular torsion.  相似文献   
100.
Aim: To compare the efficacy of 14‐day and 5‐day amoxicillin treatment on the eradication rate during tetracycline containing sequential H. pylori therapy, and also to compare the eradication rate of this regimen with those used in similar studies performed in Turkey. Method: This study included 112 patients infected with H. pylori that were randomized into 2 groups. In group A, patients (n = 56) received pantoprazole (40 mg BID) and amoxicillin (1 g BID) for 5 days, followed by pantoprazole (40 mg BID), tetracycline (500 mg QID), and metronidazole (500 mg TID) for the remaining 9 days. In group B, patients (n = 56) received pantoprazole (40 mg BID) and amoxicillin (1 g BID) for 5 days, followed by pantoprazole (40 mg BID), tetracycline (500 mg QID), metronidazole (500 mg TID), and amoxicillin (1 g BID) for the remaining 9 days. Eradication rates were calculated using both intention‐to‐treat (ITT) and per‐protocol (PP) analyses. Results: In all, 112 patients were subjected to ITT analysis and 109 patients completed the study. In group A, H. pylori eradication was achieved in 46 (82.1%) of the 56 patients included in the ITT analysis and in 46 (83.6%) of the 55 patients included in the PP analysis. In group B, H. pylori eradication was achieved in 44 (78.57%) of the 56 patients included in the ITT analysis and in 44 (81.48%) of the 54 patients included in the PP analysis ( Table 2 ). The eradication rates were not statistically significant between the 2 groups (p > .005).
Table 2. Eradication rates in the two study groups
Group A Group B p
n ITT/PP n ITT/PP
Eradication
Female 21 70%/72.4% 34 79.06%/82.9% NS
Male 25 6.1%/96.1% 10 76.9%/76.9% NS
Total 46 82.1%/83.6% 44 78.57%/81.48% NS
  • NS, not significant; PP, per‐protocol; ITT, intention‐to‐treat.
Conclusion: Extended duration of amoxicillin treatment during the entire tetracycline containing sequential therapy period did not improve the H. pylori eradication rate. As a consequence, sequential therapy using 5‐day amoxicillin is an acceptable first‐line therapy option for the eradication of H. pylori in Turkey.  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