收费全文 | 5006篇 |
免费 | 264篇 |
国内免费 | 10篇 |
耳鼻咽喉 | 18篇 |
儿科学 | 164篇 |
妇产科学 | 170篇 |
基础医学 | 815篇 |
口腔科学 | 76篇 |
临床医学 | 422篇 |
内科学 | 867篇 |
皮肤病学 | 96篇 |
神经病学 | 546篇 |
特种医学 | 155篇 |
外科学 | 389篇 |
综合类 | 58篇 |
预防医学 | 480篇 |
眼科学 | 285篇 |
药学 | 402篇 |
中国医学 | 8篇 |
肿瘤学 | 329篇 |
2023年 | 19篇 |
2022年 | 58篇 |
2021年 | 81篇 |
2020年 | 45篇 |
2019年 | 70篇 |
2018年 | 94篇 |
2017年 | 53篇 |
2016年 | 108篇 |
2015年 | 120篇 |
2014年 | 147篇 |
2013年 | 196篇 |
2012年 | 325篇 |
2011年 | 389篇 |
2010年 | 194篇 |
2009年 | 184篇 |
2008年 | 340篇 |
2007年 | 316篇 |
2006年 | 333篇 |
2005年 | 330篇 |
2004年 | 293篇 |
2003年 | 257篇 |
2002年 | 284篇 |
2001年 | 48篇 |
2000年 | 30篇 |
1999年 | 66篇 |
1998年 | 89篇 |
1997年 | 77篇 |
1996年 | 57篇 |
1995年 | 48篇 |
1994年 | 45篇 |
1993年 | 42篇 |
1992年 | 35篇 |
1991年 | 24篇 |
1990年 | 19篇 |
1989年 | 14篇 |
1988年 | 36篇 |
1987年 | 19篇 |
1986年 | 22篇 |
1985年 | 24篇 |
1984年 | 19篇 |
1983年 | 19篇 |
1982年 | 17篇 |
1981年 | 15篇 |
1980年 | 18篇 |
1979年 | 14篇 |
1978年 | 15篇 |
1977年 | 14篇 |
1974年 | 14篇 |
1964年 | 13篇 |
1962年 | 13篇 |
Many interventions targeting executive function (EF) development in the preschool period, where malleability might be particularly high, have been created and evaluated. We conducted a meta-analysis of randomized controlled trials (RCTs) on the effects of these interventions on (a) EFs in preschool children from the general population as well as preschool children with (symptoms of) attention-deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD), and (b) ADHD and ODD symptoms in preschool children with ADHD/ODD (symptoms). Literature search yielded 35 RCTs. Risk of bias of the individual studies was assessed. A random-effects model was used. Moderator effects were tested using mixed model analyses. The overall effects on EFs were: d = 0.46 (95% CI 0.30–0.61) for working memory (WM), d = 0.30 (95% CI 0.21–0.38) for inhibitory control (IC), d = 0.33 (95% CI − 0.04 to 0.71) for reward-related IC, and d = 0.47 (95% CI 0.28–0.66) for flexibility. In children with ADHD/ODD, mean effects were d = 0.64 (95% CI 0.31–0.96) for WM and d = 0.46 (95% CI 0.07–0.84) for IC. Studies on reward-related IC and FL were lacking. Effects on ODD and ADHD symptoms were d = 0.40 (95% CI − 0.23 to 1.03) and d = 0.28 (95% CI − 0.08 to 0.64), respectively. Interventions targeting multiple EFs and using interpersonal cognitive scaffolding approaches showed large and statistically significant effects on ADHD and ODD symptoms. In preschool children of the general population and in those with ADHD/ODD (symptoms), interventions led to an improvement of EF performance. In children with ADHD and ODD, cognitive scaffolding interventions were most effective in terms of reducing ADHD and ODD symptoms. However, more well-controlled studies need to be conducted before any firm conclusions can be drawn.
相似文献The pentose phosphate pathway (PPP) has been shown to play an important role in the metabolism of cancer cells. The transketolase-like 1 gene (TKTL1) encodes an enzyme representing an essential component of this pathway. Its expression has been demonstrated to correlate with stage and outcome in various tumors. The aim of the present study was to assess expression patterns and the prognostic role of TKTL1 in muscle-invasive bladder cancer (MIBC).
Patients and methodsThe expression of TKTL1 was assessed in a tissue microarray consisting of histopathologically benign and malign tissue of 112 patients who underwent radical cystectomy due to MIBC. Cytoplasmatic and nuclear expression were assessed by immunohistochemistry and compared separately with clinicopathologic parameters and outcome.
ResultsCytoplasmatic expression of TKTL1 was exclusively present in tumor tissue. In contrast, the proportion of nuclei positive for TKTL1 was higher in histopathologically benign tissue compared with malign tissue. No correlation was observed between cytoplasmatic or nuclear TKTL1 expression and tumor stage, grade or the presence of metastases. Patients with lymph node involvement showed a decreased frequency of cytoplasmatic expression compared with node-negative patients (p = 0.01). However, no further correlation was observed between the expression of TKTL1 and clinical outcome of patients.
ConclusionsThe present study shows that the cytoplasmatic expression of TKTL1 is specific for MIBC tissue compared with histopathologically benign urothelium. This specific expression is present in a subgroup of MIBC potentially identifying patients with activated PPP suitable for a targeted inhibition of sugar metabolism. In contrast to other malignancies, TKTL1 shows no prognostic significance in MIBC.
相似文献