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   838篇
  免费   23篇
耳鼻咽喉   5篇
儿科学   33篇
妇产科学   18篇
基础医学   105篇
口腔科学   27篇
临床医学   78篇
内科学   133篇
皮肤病学   20篇
神经病学   67篇
特种医学   26篇
外国民族医学   1篇
外科学   82篇
综合类   13篇
一般理论   1篇
预防医学   99篇
眼科学   9篇
药学   45篇
中国医学   3篇
肿瘤学   96篇
  2024年   21篇
  2023年   24篇
  2022年   48篇
  2021年   74篇
  2020年   44篇
  2019年   43篇
  2018年   46篇
  2017年   29篇
  2016年   21篇
  2015年   34篇
  2014年   39篇
  2013年   43篇
  2012年   65篇
  2011年   71篇
  2010年   31篇
  2009年   27篇
  2008年   40篇
  2007年   40篇
  2006年   28篇
  2005年   26篇
  2004年   18篇
  2003年   11篇
  2002年   22篇
  2001年   2篇
  2000年   1篇
  1998年   5篇
  1997年   1篇
  1995年   1篇
  1993年   1篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1987年   1篇
排序方式: 共有861条查询结果,搜索用时 46 毫秒
81.
Successful endodontic treatment requires advanced materials to eliminate biofilm This study aims to assess the penetration depth and the effectiveness of Boswellia sacra as a novel intracanal medicament compared with calcium hydroxide against Enterococcus faecalis biofilm. 60 single-rooted teeth were decoronated, prepared and sterilised. Fifty teeth were contaminated with a culture of E. faecalis (ATCC 19433) for 21 days. Two teeth were used to confirm the biofilm using scanning electron microscope. For colony-forming unit (CFU), 40 samples were divided into one control group (calcium hydroxide) and the other experimental group (B. sacra). Each group was divided into two subgroups to be tested at 3 and 7 days. The minimum inhibitory concentration (MIC) of B. sacra was determined, and the B. sacra's ethanolic extract medicament was prepared. Eight discs divided into groups similar to CFU were used to evaluate live/dead bacteria using confocal laser scanning microscopy (CLSM). Ten teeth were selected for penetration depth using CLSM. The intracanal medicaments were mixed with 0.1% rhodamine B. were inserted into the root canals 0.2 slices were dissected and viewed under CLSM. The MIC of B. sacra was 1.25 mg/ml. The CFU evaluation proved that B. sacra are more effective than calcium hydroxide in the 3 days groups. However, it was statistically insignificant compared with calcium hydroxide after 7 days. The depth of penetration of B. sacra exceeds that of calcium hydroxide. B. sacra is an effective intracanal medicament.  相似文献   
82.
83.
Purpose: Unresolved controversy exists concerning the optimum restorative material to reinforce the thin‐walled roots of endodontically treated teeth to improve their fracture resistance under occlusal load. This study evaluated the effectiveness of irrigant, dowel type, and root‐reinforcing material on the fracture resistance of thin‐walled endodontically treated teeth. Materials and Methods: The root canals of 140 maxillary central incisors were enlarged and equally divided into seven groups according to the canal irrigant: no irrigant (control), 5% hydrogen peroxide, 5% sodium hypochlorite, a combination of 5% hydrogen peroxide and sodium hypochlorite, 15% ethylenediaminotetraacetic acid (EDTA), 10% lactic acid, or 20% lactic acid. Within each group, root canals were lined with composite resin (PermaFlo) or glass ionomer cement (Fuji II LC). A light‐transmitting plastic dowel (Luminex) was used to create space for a quartz fiber‐reinforced dowel (Aestheti Post) or a titanium alloy dowel (ParaPost XH) and to cure the restorative materials. Following dowel cementation and restoration of the roots with composite core, the teeth were submitted to fracture resistance testing, and data were analyzed with 3‐way ANOVA followed by Ryan‐Einot‐Gabriel‐Welsch Multiple Range Test (α= 0.05). Results: Fracture resistance values were significantly different among irrigants, restorative materials, and their interaction (p < 0.001); however, the dowel type was not significantly different (p= 0.51). Conclusions: Thin‐walled roots that had the smear layer removed with lactic acid and that were then lined with composite resin had a higher fracture resistance.  相似文献   
84.
85.
Objectives  To evaluate the mortality experience of workers at a major chemical manufacturing site and to examine brain and liver cancers excesses reported at this site in previous studies. Methods  This study included 9,730 employees at the Texas City location who worked between 1940 and 2001. Standardized mortality ratios and confidence intervals were calculated. Results  There was less than expected deaths due to all cause mortality and no increase in all cancer mortality. Brain tumor mortality, which did exceed expected rates in past years, was at expected levels in recent years. Liver cancer mortality was greater than expected. Conclusion  Brain tumor mortality was either due to chance in the early years or the cause of the brain tumors has been eliminated. Mortality due to liver cancer is higher than expected but only among men hired before 1950. Eugenio Salazar is deceased.  相似文献   
86.
Adrenal insufficiency is a life-threatening disorder which must be treated with glucocorticoid replacement and needs permanent dose adjustment during patient's different somatic situations. Insufficient glucocorticoid doses result in adrenal crisis and must be treated with intravenous hydrocortisone. The patient was known with Adrenal insufficiency and was treated optimally with fludrocortisone and prednisolone since seven years with no history of adrenal crisis. The patient was admitted with abdominal pain, weakness, fatigue and nausea developed 3-4 days after taking psyllium, a bulking agent, prescribed by a surgeon to diagnose anal fissure. Detailed medical history, physical examinations, laboratory and imaging examinations did not approve any other cause of adrenal crisis. Psyllium may interfere with gastrointestinal absorption of prednisolone and/or fludrocortisone and trigger acute adrenal crisis in patients with adrenal insufficiency.  相似文献   
87.
88.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency may cause severe hyperbilirubinemia with bilirubin encephalopathy unless intervention is initiated. The aim of this study was to assess the efficacy of clofibrate in full term G6PD deficient neonates with jaundice. A randomized clinical trial study was performed in two groups of full-term G6PD deficient jaundiced neonates (clofibrate treated group, n = 21; control group, n = 19). Infants in the clofibrate group received a single oral dose of 100 mg/kg clofibrate, whereas control group received nothing. Both groups were treated with phototherapy. Serum total and direct bilirubin levels were measured at the onset of treatments, 16, 24 and 48 hours later. On enrollment, the mean total serum bilirubin (TSB) level in the clofibrate treated group was 18.40 +/- 2.41 and in the control group was 17.49 +/- 1.03 (p = 0.401). At 16, 24 and 48 hours of treatment, the mean TSB in the clofibrate group were 15.2 +/- 1.9, 12.6 +/- 2.4, and 10.1 +/- 2.4 and in the control group were 16.5 +/- 1.2, 13.3 +/- 2.2 and 11.4 +/- 2.4, respectively (p = 0.047). At 48 hours, 7 (33%) cases in the clofibrate group and one (5%) case in the control group were discharged with a TSB < 10 mg/dl (p = 0.031). No side effects were observed on serial examinations during hospitalization, or on the 1st and 7th days after discharge. The results show that clofibrate induces a faster decline in serum total bilirubin level, a shorter duration of phototherapy, and hospitalization with no side effects in full-term G6PD deficient neonates with jaundice.  相似文献   
89.

Background

Stage IV non-small cell lung cancer (NSCLC) is thought to uniformly carry a poor prognosis with a median survival of less than 1 year and 5-year survival of less than 5%. In patients with a low volume (i.e. single site) of distant disease, the prognosis is slightly more favorable than that of more advanced (i.e. multiple sites of metastases) disease. For those with limited metastases, we developed a paradigm of adding concurrent chemotherapy and radiotherapy to the primary tumor once the tumor demonstrated chemotherapy sensitivity.

Methods

Charts of patients from 1999-2006 with non-small cell lung cancer were reviewed to find those with a single extra-thoracic site of disease treated with combined modality therapy. We found nine patients of 640 who met these criteria. Initial treatment consisted of induction chemotherapy, except for brain metastases which were managed first (n=1). If patients experienced a response to chemotherapy without new metastases, the extra-thoracic site was treated for total control with curative dose chemoradiotherapy to the primary site. Survival, time to progression, and sites of progression were assessed.

Results

Median survival was 28 months (95% CI 18-50 mo) with median time to progression of 15 months (95% CI 8-24 mo). All except one patient progressed in the CNS, either with brain metastases (n=7) or leptomeningeal disease (n=1).

Conclusions

Such an approach offers the potential for enhanced quality and quantity of survival by incorporating aggressive RT for select patients without disease progression after induction chemotherapy. Patients tended to fail in the CNS, suggesting the importance of continued surveillance of the neuraxis or possibly prophylactic cranial irradiation. Future plans will correlate outcomes with molecular markers.  相似文献   
90.
Genomic rearrangements are common, occur by largely unknown mechanisms, and can lead to human diseases. We previously demonstrated that some genome rearrangements occur in budding yeast through the fusion of two DNA sequences that contain limited sequence homology, lie in inverted orientation, and are within 5 kb of one another. This inverted repeat fusion reaction forms dicentric chromosomes, which are well-known intermediates to additional rearrangements. We have previously provided evidence indicating that an error of stalled or disrupted DNA replication forks can cause inverted repeat fusion. Here we analyze how checkpoint protein regulatory pathways known to stabilize stalled forks affect this form of instability. We find that two checkpoint pathways suppress inverted repeat fusion, and that their activities are distinguishable by their interactions with exonuclease 1 (Exo1). The checkpoint kinase Rad53 (Chk2) and recombination protein complex MRX(MRN) inhibit Exo1 in one pathway, whereas in a second pathway the ATR-like kinases Mec1 and Tel1, adaptor protein Rad9, and effector kinases Chk1 and Dun1 act independently of Exo1 to prevent inverted repeat fusion. We provide a model that indicates how in Rad53 or MRX mutants, an inappropriately active Exo1 may facilitate faulty template switching between nearby inverted repeats to form dicentric chromosomes. We further investigate the role of Rad53, using hypomorphic alleles of Rad53 and null mutations in Rad9 and Mrc1, and provide evidence that only local, as opposed to global, activity of Rad53 is sufficient to prevent inverted repeat fusion.  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