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   10906篇
  免费   704篇
  国内免费   50篇
耳鼻咽喉   302篇
儿科学   273篇
妇产科学   299篇
基础医学   1541篇
口腔科学   418篇
临床医学   904篇
内科学   2546篇
皮肤病学   201篇
神经病学   1247篇
特种医学   219篇
外科学   1004篇
综合类   20篇
一般理论   5篇
预防医学   618篇
眼科学   132篇
药学   687篇
中国医学   36篇
肿瘤学   1208篇
  2024年   12篇
  2023年   109篇
  2022年   186篇
  2021年   420篇
  2020年   267篇
  2019年   316篇
  2018年   349篇
  2017年   288篇
  2016年   347篇
  2015年   369篇
  2014年   494篇
  2013年   601篇
  2012年   924篇
  2011年   1036篇
  2010年   513篇
  2009年   448篇
  2008年   782篇
  2007年   712篇
  2006年   639篇
  2005年   666篇
  2004年   599篇
  2003年   545篇
  2002年   479篇
  2001年   58篇
  2000年   35篇
  1999年   51篇
  1998年   86篇
  1997年   60篇
  1996年   45篇
  1995年   46篇
  1994年   33篇
  1993年   32篇
  1992年   23篇
  1991年   11篇
  1990年   7篇
  1989年   12篇
  1988年   8篇
  1987年   2篇
  1986年   14篇
  1985年   3篇
  1984年   5篇
  1983年   4篇
  1982年   5篇
  1980年   4篇
  1979年   2篇
  1978年   2篇
  1976年   3篇
  1974年   2篇
  1973年   2篇
  1968年   1篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
71.
A human recombinant monoclonal Fab fragment that specifically recognizes all the influenza A virus strains tested was produced in transformed Escherichia coli using the phage display technique. No strain of influenza B virus reacted with it. It was purified after four cycles of panning and by a single passage through an immunoaffinity column. About 1 mg of pure monoclonal antibody was obtained from 1 liter of culture medium in 3 working days. The Fab fragment reacted with a viral 27-kDa protein, which could reasonably be a matrix protein. Indirect immunofluorescence tests performed on virus-infected MDCK cells showed that this Fab fragment was at least equally efficient as other commercial monoclonal antibody-based systems in detecting influenza A viral infections. The potential advantages of human recombinant Fabs on murine monoclonal antibodies are discussed.  相似文献   
72.
Although B-cell chronic lymphocytic leukemia (B-CLL) is the most common form of leukemia in Western countries, little is known about its underlying molecular abnormalities and their prognostic significance, particularly for use in early therapeutic interventions in young patients. As TP53 tumor suppressor gene abnormalities and 11q23 deletions are reported to be prognostically adverse in hematologic malignancies, we used interphase fluorescence in situ hybridization to analyze their incidence and prognostic significance in young B-CLL patients. Bone marrow samples from 40 untreated B-CLL patients at diagnosis were studied using five yeast artificial chromosome clones from the 11q23.1 approximately q23.3 chromosomal region and a probe specific for the 17p13.1 locus. Twenty-three patients (58%) carried 11q deletions. Interestingly, 16 of 17 patients (94%) who showed early disease progression exhibited this chromosomal abnormality, suggesting that 11q deletions may help to identify more aggressive disease in early stage patients. In contrast, monoallelic TP53 deletions were found in all of the patients. The TP53 and 11q deletions were only present in a proportion of the clonal B-cells, which suggests that they are secondary events in B-CLL.  相似文献   
73.
74.
Journal of Public Health - Offshore wind energy is a fast growing market. Accordingly, a correspondingly large number of employees are working at the wind farms. Owing to the harsh operating...  相似文献   
75.
It is now well known how the microbiota can positively or negatively influence humans health, depending on its composition. The microbiota’s countless beneficial effects have allowed it to be defined as a genuine symbiont for our species. In an attempt to positively influence the microbiota, research has focused on probiotics and prebiotics. Probiotics are viable beneficial bacteria of various strains. Prebiotics are specific substances able to favor the development of advantageous bacteria strains. Postbiotics are a new category of compounds capable of affecting the microbiota. According to the different definitions, postbiotics include both nonviable bacteria and substances deriving from bacterial metabolism. Postbiotics are particularly promising in pediatric settings, as they offer some advantages over probiotics, including the absence of the risk of intestinal translocation or worsening of local inflammation. For these reasons, their use in fragile population categories such as newborns, and even more prematures, seems to be the best solution for improving microbiota’s health in this population. This narrative review aims to collect the research conducted so far on postbiotics’ potential in the first stages of life.  相似文献   
76.
The use of olive pomace could represent an innovative and low-cost strategy to formulate healthier and value-added foods, and bakery products are good candidates for enrichment. In this work, we explored the prebiotic potential of bread enriched with Polyphenol Rich Fiber (PRF), a defatted olive pomace byproduct previously studied in the European Project H2020 EcoProlive. To this aim, after in vitro digestion, the PRF-enriched bread, its standard control, and fructo-oligosaccharides (FOS) underwent distal colonic fermentation using the in vitro colon model MICODE (multi-unit colon gut model). Sampling was done prior, over and after 24 h of fermentation, then metabolomic analysis by Solid Phase Micro Extraction Gas Chromatography Mass Spectrometry (SPME GCMS), 16S-rDNA genomic sequencing of colonic microbiota by MiSeq, and absolute quantification of main bacterial species by qPCR were performed. The results indicated that PRF-enriched bread generated positive effects on the host gut model: (i) surge in eubiosis; (ii) increased abundance of beneficial bacterial groups, such as Bifidobacteriaceae and Lactobacillales; (iii) production of certain bioactive metabolites, such as low organic fatty acids; (iv) reduction in detrimental compounds, such as skatole. Our study not only evidenced the prebiotic role of PRF-enriched bread, thereby paving the road for further use of olive by-products, but also highlighted the potential of the in vitro gut model MICODE in the critical evaluation of functionality of food prototypes as modulators of the gut microbiota.  相似文献   
77.
ObjectiveSensory deficits are important risk factors for delirium but have been investigated in single-center studies and single clinical settings. This multicenter study aims to evaluate the association between hearing and visual impairment or bi-sensory impairment (visual and hearing impairment) and delirium.DesignCross-sectional study nested in the 2017 “Delirium Day” project.Setting and ParticipantsPatients 65 years and older admitted to acute hospital medical wards, emergency departments, rehabilitation wards, nursing homes, and hospices in Italy.MethodsDelirium was assessed with the 4AT (a short tool for delirium assessment) and sensory deficits with a clinical evaluation. We assessed the association between delirium, hearing and visual impairment in multivariable logistic regression models, adjusting for: Model 1, we included predisposing factors for delirium (ie, dementia, weight loss and autonomy in the activities of daily living); Model 2, we added to Model 1 variables, which could be considered precipitating factors for delirium (ie, psychoactive drugs and urinary catheters).ResultsA total of 3038 patients were included; delirium prevalence was 25%. Patients with delirium had a higher prevalence of hearing impairment (30.5% vs 18%; P < .001), visual impairment (24.2% vs 15.7%; P < .01) and bi-sensory impairment (16.2% vs 7.5%) compared with those without delirium. In the multivariable logistic regression analysis, the presence of bi-sensory impairment was associated with delirium in Model 1 [odds ratio (OR) 1.5, confidence interval (CI) 1.2–2.1; P = .00] and in Model 2 (OR 1.4; CI 1.1–1.9; P = .02), whereas the presence of visual and hearing impairment alone was not associated with delirium either in Model 1 (OR 0.8; CI 0.6–1.2, P = .36; OR 1.1; CI 0.8–1.4; P = .42) or in Model 2 (OR 0.8, CI 0.6–1.2, P = .27; OR 1.1, CI 0.8–1.4, P = .63).Conclusions and implicationsOur findings support the importance of routine screening and specific interventions by a multidisciplinary team to implement optimal management of sensory impairments and hence prevention and the management of the patients with delirium.  相似文献   
78.
Liver transplantation (LT) for colorectal liver metastasis (CRLM) may provide excellent survival rates in patients with unresectable disease. High tumor load is a risk factor for recurrence and low overall survival (OS) after liver resection (LR). We tested the hypothesis that LT could offer better survival than LR in patients with high tumor load. LR performed at Padua University Hospital for CRLM was compared with LT for unresectable CRLM performed both at Oslo and Padua. High tumor load was defined as tumor burden score (TBS) ≥ 9, and inclusion criteria were as in the SECA-I transplant study. 184 patients were eligible: 128 LRs and 56 LTs. 5-year OS after LR and LT was 40.5% and 54.7% (= 0.102). In the high TBS cohort, 5-year OS after LR and LT was 22.7% and 52.2% (P = 0.055). In patients with Oslo score ≤ 2 and TBS ≥ 9 (13 LR; 24 LT) the 5-year OS after LR and LT was 14.6% and 69.1% (P = 0.002). The corresponding disease-free survival (DFS) was 0% and 22.9% (P = 0.005). Selected CRLM patients with low Oslo score and high TBS could benefit from LT with survival outcomes that are far better than what is achieved by LR.  相似文献   
79.
IntroductionAdenocarcinoma of the esophagogastric junction (AEGJ) represents a poor prognostic tumor. We evaluated the recurrence pattern and risk factors associated with recurrence in patients undergoing surgical resection by AEJG.MethodsRecurrences were categorized as locoregional, peritoneal, or distant. These three recurrence groups and a non-recurrence group were compared, and overall survival (OS) and disease-free survival (DFS) for each one was obtained.ResultsWe analyzed 188 patients with curative surgical treatment. Recurrence was observed in 72 (38.3%) patients. Locoregional recurrence was observed in 17 (23.6%); 20 (27.8%) peritoneal recurrence and 35 (48.6%) distant metastasis. DFS was 9, 5, and 8 months, and OS was 21.8, 13.2, and 20.8, respectively. Tumors larger than 5 cm are risk factors for peritoneal recurrence (OR:2.88, p = 0.012). Positive lymph nodes were related to distant metastasis (OR:9.15, p = 0.040), and lymphatic invasion for locoregional recurrence (OR:3.81, p = 0.028).ConclusionAEGJ is associated with high rates of early recurrence.  相似文献   
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