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   892篇
  免费   62篇
  国内免费   2篇
耳鼻咽喉   6篇
儿科学   23篇
妇产科学   7篇
基础医学   68篇
口腔科学   49篇
临床医学   79篇
内科学   220篇
皮肤病学   25篇
神经病学   64篇
特种医学   31篇
外科学   128篇
综合类   59篇
预防医学   57篇
眼科学   24篇
药学   82篇
中国医学   3篇
肿瘤学   31篇
  2024年   4篇
  2023年   24篇
  2022年   63篇
  2021年   101篇
  2020年   60篇
  2019年   60篇
  2018年   72篇
  2017年   41篇
  2016年   34篇
  2015年   43篇
  2014年   40篇
  2013年   47篇
  2012年   66篇
  2011年   59篇
  2010年   51篇
  2009年   25篇
  2008年   43篇
  2007年   21篇
  2006年   21篇
  2005年   18篇
  2004年   22篇
  2003年   13篇
  2002年   14篇
  2001年   1篇
  2000年   1篇
  1998年   3篇
  1997年   3篇
  1995年   2篇
  1993年   1篇
  1991年   1篇
  1988年   1篇
  1985年   1篇
排序方式: 共有956条查询结果,搜索用时 15 毫秒
1.
The present investigation was aimed at studying the possible role of curcumin against N-nitrosodiethylamine (NDEA)-induced toxicity in albino rats. Administration of NDEA to rats at a concentration of 0.1 mg/ml in drinking water ad libitum for 21 days produced toxicity in them, which was evident from histopathological changes in the rat livers, and increased levels of blood serum enzyme markers, i.e. aspartate transaminase, alanine transaminase, alkaline phosphatase, and lactate dehydrogenase. In addition, the levels of oxidative stress markers like lipid peroxidation (LPO), protein carbonyl (PCC), and glutathione-S-transferase (GST) activity were elevated and the total glutathione (GSH) content was reduced in the livers. The administration of curcumin to rats at concentrations of 10, 20, and 40 mg/ml in drinking water along with 0.1 mg/ml of NDEA for 21 days effectively suppressed NDEA-induced toxicity and also resulted in a dose-dependent reduction in the levels of blood serum enzyme markers (AST, ALT, ALP, and LDH). Moreover, LPO, PCC, and GST activity were reduced and the GSH level was increased upon the administration of curcumin along with NDEA. The results obtained for the comet assay in rat hepatocytes and blood lymphocytes showed a significant dose-dependent decrease in the mean tail length. The micronucleus assay performed on rat hepatocytes also showed a dose-dependent reduction in the frequency of micronucleated cells along with curcumin administration. These results suggest that curcumin has a protective role against NDEA-induced toxicity in albino rats.  相似文献   
2.
Bacteria or their products may cause chronic inflammation and subsequent bone loss. This inflammation and bone loss may be associated with significant morbidity in chronic otitis media, periodontitis, endodontic lesions, and loosening of orthopedic implants caused by lipopolysaccharide (LPS)-contaminated implant particles. Currently, it is not clear how bacteria or endotoxin-induced bone resorption occurs and what cell types are involved. Here we report that Porphyromonas gingivalis, a periodontal pathogen, and Escherichia coli LPS induce osteoclastic cell formation from murine leukocytes in the absence of osteoblasts. In contrast, stimulation with parathyroid hormone had no effect. These multinucleated, tartrate-resistant acid phosphatase-positive cells were positive for receptor activator of NF-kappaB (RANK), the receptor for osteoprotegerin ligand (OPGL), also known as RANK ligand (RANKL). Blocking antibodies demonstrated that their formation was dependent upon expression of OPGL and, to a lesser extent, on tumor necrosis factor alpha. Mononuclear cells represented a significant source of OPGL production. In vivo, P. gingivalis injection stimulated OPGL expression in both mononuclear leukocytes and osteoblastic cells. Thus, these findings describe a pathway by which bacteria could enhance osteolysis independently of osteoblasts and suggest that the mix of cells that participate in inflammatory and physiologic bone resorption may be different. This may give insight into new targets of therapeutic intervention.  相似文献   
3.
In the past several decades, marine organisms have generouslygifted to the pharmaceutical industries numerous naturallybioactive compounds with antiviral, antibacterial,antimalarial, anti-inflammatory, antioxidant, and anticancerpotentials. But till date only few anticancer drugs (cytarabine,vidarabine) have been commercially developed from marinecompounds while several others are currently in differentclinical trials. Majority of these compounds were tested in thetumor xenograft models, however, lack of anticancer potentialdata in the chemical- and/or oncogene-induced pre-initiationanimal carcinogenesis models might have cost some of the marineanticancer compounds an early exit from the clinical trials. Thisreview critically discusses importance of preclinicalevaluation, failure of human clinical trials with certainpotential anticancer agents, the screening tests used, and choiceof biomarkers.  相似文献   
4.
In the present study, two of the probable an umor marine compounds, manzamine A and sarcophine, were screened using benzo[a]pyrene (BP)-derived DNA adduct formation in MCF-7 cells as intermediary biomarker. Briefly, MCF-7 cells were treated with the compounds for 24 h followed by treatment with BP (0.5 μM). After 24h incubation, cellular DNA was isolated and analyzed for BP-derived DNA adducts by 32P-postlabeling technique. Manzamine A and sarcophine increased the BP-DNA adducts by 2 to 4-folds. Further, manzamine A (50 μM) substantially down regulated the expression of p53 while sarcophine (50 μM) slightly induced the level of p21. The residual DNA repair ability was almost completely abolished by manzamine A while sarcophine was ineffective. Based on our preliminary results, these compounds may be classified as potential genotoxic.  相似文献   
5.
6.
7.
Background: The Vulnerable Elders Survey (VES-13) is commonly used to identify older patients who may benefit from Comprehensive Geriatric Assessment (CGA) prior to cancer treatment. The optimal cut point of the VES-13 to identify those whose final oncologic treatment plan would change after CGA is unclear. We hypothesized that patients with high positive VES-13 scores (7–10)have a higher likelihood of a change in treatment compared to low positive scores (3–6).Methods: Retrospective review of a customized database of all patients seen for pre-treatment assessment in an academic geriatric oncology clinic from June 2015 to June 2019. Various VES-13 cut points were analyzed to identify those individuals whose treatment was modified after CGA. Area under the curve (AUC) was calculated and subgroups of patients treated locally or systemically were also examined to determine if performance varied by treatment modality.Results: We included 386 patients with mean age 81, 58% males. Gastrointestinal cancer was the most common site (31%) and 60% were planned to receive curative treatment. The final treatment plan was modified in 59% overall, with 52.7% modified with VES-13 scores 7–10, 50.8% with scores 3–6 and 28.1% with scores <3 (P = 0.002). VES-13 performance in predicting treatment modification was similar for cut points 3 (AUC 0.58), 4 (0.59), 5 (0.59), and 6 (0.59) and in those considering local treatment vs. chemotherapy.Conclusions: A positive VES-13 score was associated with final oncologic treatment plan modification. A high positive score was not superior to the conventional cut point of ≥3.  相似文献   
8.
9.
10.
Hypertension is the most common cardiovascular disease worldwide. Moreover, management of hypertension requires long-term treatment that may result in poor patient compliance with conventional dosage forms due to greater frequency of drug administration. Although there is availability of a plethora of therapeutically effective antihypertensive molecules, inadequate patient welfare is observed; this arguably presents an opportunity to deliver antihypertensive agents through a different route. Ever since the transdermal drug delivery came into existence, it has offered great advantages including non-invasiveness, prolonged therapeutic effect, reduced side effects, improved bioavailability, better patient compliance and easy termination of drug therapy. Attempts were made to develop the transdermal therapeutic system for various antihypertensive agents, including β-blockers, an important antihypertensive class. β-blockers are potent, highly effective in the management of hypertension and other heart ailments by blocking the effects of normal amounts of adrenaline in the heart and blood vessels. The shortcomings associated with β-blockers such as more frequent dose administration, extensive first pass metabolism and variable bioavailability, make them an ideal candidate for transdermal therapeutic systems. The present article gives a brief view of different β-blockers formulated as transdermal therapeutic system in detail to enhance the bioavailability as well as to improve patient compliance. Constant improvement in this field holds promise for the long-term success in technologically advanced transdermal dosage forms being commercialized sooner rather than later.  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