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   2234篇
  免费   112篇
  国内免费   4篇
耳鼻咽喉   13篇
儿科学   40篇
妇产科学   71篇
基础医学   258篇
口腔科学   118篇
临床医学   218篇
内科学   531篇
皮肤病学   49篇
神经病学   172篇
特种医学   58篇
外科学   275篇
综合类   5篇
预防医学   90篇
眼科学   23篇
药学   162篇
中国医学   4篇
肿瘤学   263篇
  2023年   14篇
  2022年   19篇
  2021年   40篇
  2020年   34篇
  2019年   43篇
  2018年   51篇
  2017年   39篇
  2016年   40篇
  2015年   52篇
  2014年   74篇
  2013年   91篇
  2012年   130篇
  2011年   141篇
  2010年   59篇
  2009年   89篇
  2008年   81篇
  2007年   86篇
  2006年   110篇
  2005年   138篇
  2004年   141篇
  2003年   83篇
  2002年   67篇
  2001年   75篇
  2000年   77篇
  1999年   50篇
  1998年   25篇
  1997年   19篇
  1996年   21篇
  1995年   32篇
  1994年   11篇
  1993年   10篇
  1992年   35篇
  1991年   33篇
  1990年   50篇
  1989年   41篇
  1988年   35篇
  1987年   29篇
  1986年   26篇
  1985年   17篇
  1984年   18篇
  1983年   8篇
  1982年   8篇
  1979年   10篇
  1977年   8篇
  1974年   7篇
  1973年   8篇
  1971年   11篇
  1969年   8篇
  1968年   6篇
  1967年   6篇
排序方式: 共有2350条查询结果,搜索用时 187 毫秒
71.

Background/Aims

The prognosis of pancreatic adenocarcinoma (PAC) is poor. The serum carbohydrate antigen 19-9 (CA 19-9) level has been identified as a prognostic indicator of recurrence and reduced overall survival. The aim of this study was to identify preoperative prognostic factors and to create a prognostic model able to assess the early recurrence risk for patients with resectable PAC.

Methods

A series of 177 patients with PAC treated surgically at the St. Andrea Hospital of Rome between January 2003 and December 2011 were reviewed retrospectively. Univariate and multivariate analyses were utilized to identify preoperative prognostic indicators.

Results

A preoperative CA 19-9 level >228 U/mL, tumor size >3.1 cm, and the presence of pathological preoperative lymph nodes statistically correlated with early recurrence. Together, these three factors predicted the possibility of an early recurrence with 90.4% accuracy. The combination of these three preoperative conditions was identified as an independent parameter for early recurrence based on multivariate analysis (p=0.0314; hazard ratio, 3.9811; 95% confidence interval, 1.1745 to 15.3245).

Conclusions

PAC patient candidates for surgical resection should undergo an assessment of early recurrence risk to avoid unnecessary and ineffective resection and to identify patients for whom palliative or alternative treatment may be the treatment of choice.  相似文献   
72.
73.
Memory for visual objects, although typically highly accurate, can be distorted, especially in older adults. Here we asked whether also erroneous identifications of visual objects subsequently corrected and replaced by a correct identification might induce false recognitions, and whether this is more likely to occur in older people. For this aim a new paradigm was developed. In the first phase, participants performed a visual object identification task with degraded pictures of objects and produced correct and false but subsequently corrected identifications. In the second phase, participants performed a surprise recognition task in which also false identifications were presented. False identifications elicited false recognitions, with a stronger and more reliable effect in elderly participants, suggesting that correcting the initial visual error is not sufficient to correct the memory for the experience. Moreover, misidentification-related false recognitions coexisted in memory along with correct recognitions of correct identifications. These findings are discussed in relation with age-related deficits in memory updating and strategic retrieval.  相似文献   
74.
The calcifiyng epithelial odontogenic tumor (CEOT) and the squamous odontogenic tumor (SOT) are rare and benign odontogenic tumors that affect the jaw. This article describes the diagnostic and surgical management of a multifocal CEOT in the mandible and maxilla associated with an SOT. This case is the first to demonstrate that there may be a multifocal variant of CEOT associated with an SOT that has not been previously recognized. Clinical, radiographic, and histologic signs are reported. Treatment modality, oral rehabilitation, and long-term follow-up are shown. Because of the rarity of this kind of simultaneous pathologic association, it is of paramount, and indeed obvious, importance to prospective reviewers that published reports are produced meticulously, including all clinically, radiographically, and histologically relevant data.  相似文献   
75.
Metabolomic fingerprint of breast cancer cells treated with the antidiabetic drug metformin revealed a significant accumulation of 5-formimino-tetrahydrofolate, one of the tetrahydrofolate forms carrying activated one-carbon units that are essential for the de novo synthesis of purines and pyrimidines. De novo synthesis of glutathione, a folate-dependent pathway interconnected with one-carbon metabolism was concomitantly depleted in response to metformin. End-product reversal studies demonstrated that thymidine alone leads to a significant but incomplete protection from metformin's cytostatic effects. The addition of the substrate hypoxanthine for the purine salvage pathway produces major rightward shifts in metformin's growth inhibition curves. Metformin treatment failed to activate the DNA repair protein ATM kinase and the metabolic tumor suppressor AMPK when thymidine and hypoxanthine were present in the extracellular milieu. Our current findings suggest for the first time that metformin can function as an antifolate chemotherapeutic agent that induces the ATM/AMPK tumor suppressor axis secondarily following the alteration of the carbon flow through the folate-related one-carbon metabolic pathways.  相似文献   
76.
The objective of this study was to analyze the impact of family history of suicidal behaviour on psychopathlogical features of inmates. A sample of 1,179 prisoners had a psychiatric interview including the Brown-Goodwin Assessment for Lifetime History of Aggression (BGLHA). Prisoners completed the Barratt Impulsivity Scale (BIS), Buss-Durkee Hostility Inventory (BDHI), and Eysenck Personality Questionnaire (EPQ). Prisoners with a family history of suicide were compared with prisoners without a family history of suicide on clinical and personality variables. Seventy of the 1,179 prisoners (5.9%) had a family history of suicide. Significantly more FHS positive prisoners had attempted suicide compared with FHS negative prisoners (36% vs. 12%, P < 0.0001). Significantly more FHS positive prisoners had a previous history of convictions, a history of juvenile convictions, and had exhibited aggressive behavior in jail. FHS positive prisoners had significantly higher aggression scores on the BGLHA, higher hostility scores on the BDHI, higher impulsivity scores on the BIS, and higher neuroticism scores on the EPQ. A family history of suicide may be a useful clinical indicator that a prisoner is at increased risk for suicidal behaviour and may have problems with impulsive-aggression.  相似文献   
77.
The aim of this study was to evaluate the quantity and quality of bony regeneration after we had used recombinant human bone morphogenetic protein-7 (rhBMP-7 to augment the floor of the maxillary sinus. Nine consecutive patients with bilateral posterior maxillary atrophy who required augmentation of the sinus for interposition of implants were treated simultaneously with rhBMP-7 (Osigraft) with deproteinised bone substitute (0.5 g on the test side) and with deproteinised bone alone (2.0 g on the control side). Computed tomographic images preoperatively, immediately postoperatively, and at 4 months postoperatively showed a mean (SD) postoperative gain of 10.8 (3.0) mm on the test side and of 10.2 (1.8) mm on the control side. Histological and histomorphometric analyses of biopsy specimens showed that there was significantly more new bone on the control side (19.9 (6.8)%) than on the test side (6.6 (4.8)%). In this pilot controlled trial of the use of rhBMP-7, histological analyses showed that it resulted in the formation of less bone than treatment with inorganic bovine hydroxyapatite.  相似文献   
78.
The aim of this review is to evaluate the use of chemotherapy (CT) in the treatment of squamous vulvar cancer. Since the 90s there was a continuous evolution in the therapeutic approach to this tumour. Although primary surgery is now considered the most effective approach, there are advanced diseases in which surgery may compromise anatomical structures causing severe mutilation. These are the reasons why CHT, with or without concomitant radiotherapy RT, started to be strongly recommended as neoadjuvant strategy. Chemotherapeutic agents have also been used alone as adjuvant treatment or in association with RT, by exploiting the radiosensitizing effect of these drugs. There are few data about the use of CHT as palliative treatment but recent studies point to the use of target therapy. In conclusion, clinical data and the evidence of chemo-sensitivity in vulvar squamous cell carcinoma open new possibilities to future research in this field.  相似文献   
79.
80.
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