全文获取类型
收费全文 | 27053篇 |
免费 | 1384篇 |
国内免费 | 930篇 |
专业分类
耳鼻咽喉 | 252篇 |
儿科学 | 583篇 |
妇产科学 | 348篇 |
基础医学 | 4015篇 |
口腔科学 | 562篇 |
临床医学 | 1782篇 |
内科学 | 4252篇 |
皮肤病学 | 414篇 |
神经病学 | 2946篇 |
特种医学 | 498篇 |
外国民族医学 | 3篇 |
外科学 | 1772篇 |
综合类 | 3485篇 |
预防医学 | 1097篇 |
眼科学 | 251篇 |
药学 | 4764篇 |
3篇 | |
中国医学 | 1012篇 |
肿瘤学 | 1328篇 |
出版年
2023年 | 178篇 |
2022年 | 297篇 |
2021年 | 460篇 |
2020年 | 486篇 |
2019年 | 1057篇 |
2018年 | 978篇 |
2017年 | 644篇 |
2016年 | 538篇 |
2015年 | 589篇 |
2014年 | 1075篇 |
2013年 | 1377篇 |
2012年 | 1142篇 |
2011年 | 1330篇 |
2010年 | 1266篇 |
2009年 | 1257篇 |
2008年 | 1323篇 |
2007年 | 1260篇 |
2006年 | 1129篇 |
2005年 | 934篇 |
2004年 | 968篇 |
2003年 | 937篇 |
2002年 | 746篇 |
2001年 | 729篇 |
2000年 | 614篇 |
1999年 | 629篇 |
1998年 | 512篇 |
1997年 | 439篇 |
1996年 | 353篇 |
1995年 | 297篇 |
1994年 | 274篇 |
1993年 | 227篇 |
1992年 | 172篇 |
1991年 | 171篇 |
1990年 | 137篇 |
1989年 | 152篇 |
1988年 | 102篇 |
1986年 | 107篇 |
1985年 | 465篇 |
1984年 | 637篇 |
1983年 | 504篇 |
1982年 | 479篇 |
1981年 | 458篇 |
1980年 | 364篇 |
1979年 | 340篇 |
1978年 | 234篇 |
1977年 | 177篇 |
1976年 | 198篇 |
1975年 | 191篇 |
1974年 | 154篇 |
1973年 | 148篇 |
排序方式: 共有10000条查询结果,搜索用时 918 毫秒
1.
目的 探讨TRIM23基因对骨肉瘤细胞增殖能力的影响.方法 应用Western blot实验检测TRIM23基因在骨肉瘤细胞中的表达;应用shRNA质粒转染骨肉瘤细胞系U2OS,通过MTT与平板克隆形成实验评估细胞增殖能力;应用Westernblot实验检测U2OS细胞Akt/P53/P21通路的表达改变.结果 TRIM23蛋白在骨肉瘤细胞中的表达高于成骨细胞;沉默TRIM23基因可以抑制骨肉瘤细胞的增殖能力;沉默TRIM23基因下调P-Akt表达,但总Akt的表达无明显改变,上调P53与P21的表达.结论 TRIM23在骨肉瘤细胞中表达升高,TRIM23能通过调节Akt/P53/P21通路影响骨肉瘤细胞的增殖. 相似文献
2.
《Clinical neurophysiology》2021,132(9):2003-2011
ObjectiveA large N20 and P25 of the median nerve somatosensory evoked potential (SEP) predicts short survival in amyotrophic lateral sclerosis (ALS). We investigated whether high frequency oscillations (HFOs) over N20 are enlarged and associated with survival in ALS.MethodsA total of 145 patients with ALS and 57 healthy subjects were studied. We recorded the median nerve SEP and measured the onset-to-peak amplitude of N20 (N20o-p), and peak-to-peak amplitude between N20 and P25 (N20p-P25p). We obtained early and late HFO potentials by filtering SEP between 500 and 1 kHz, and measured the peak-to-peak amplitude. We followed up patients until endpoints (death or tracheostomy) and analyzed the relationship between SEP or HFO amplitudes and survival using a Cox analysis.ResultsPatients showed larger N20o-p, N20p-P25p, and early and late HFO amplitudes than the control values. N20p-P25p was associated with survival periods (p = 0.0004), while early and late HFO amplitudes showed no significant association with survival (p = 0.4307, and p = 0.6858, respectively).ConclusionsThe HFO amplitude in ALS is increased, but does not predict survival.SignificanceThe enlarged HFOs in ALS might be a compensatory phenomenon to the hyperexcitability of the sensory cortex pyramidal neurons. 相似文献
3.
目的:探索嘌呤能受体X1(purinergic receptor,P2RX1)与肺腺癌(LUAD)患者预后及免疫细胞浸润的相关性。方法:利用生物信息学技术分析非小细胞肺癌中P2RX1的表达及其甲基化与患者预后的关系,对P2RX1共表达基因进行富集分析并筛选核心基因。利用TIMER 2.0数据库、R软件等分析P2RX1与免疫细胞、免疫检查点、免疫基质评分等的相关性。结果:P2RX1在LUAD中表达下调,低表达P2RX1的患者预后较差(P<0.05),且P2RX1与肿瘤纯度、分期等临床病理因素有关(P<0.05)。P2RX1的表达与肺鳞癌患者预后无明显相关。Cg06475633等P2RX1 CpG位点甲基化与患者预后相关。P2RX1共表达基因主要富集于免疫细胞活化、分化等通路和生物学进程,核心基因主要包括BTK、IKZF1等。P2RX1的表达与B细胞浸润、免疫/基质评分、PD-1、CTLA-4等多个免疫检查点显著相关(P<0.05)。结论:P2RX1有望成为LUAD诊断和免疫治疗的新靶点。 相似文献
4.
《Gaceta sanitaria / S.E.S.P.A.S》2016,30(5):389-392
Life expectancy for people with severe mental disorders is up to 25 years less in comparison to the general population, mainly due to diseases caused or worsened by smoking. However, smoking is usually a neglected issue in mental healthcare settings. The aim of this article is to describe a strategy to improve tobacco control in the hospital mental healthcare services of Catalonia (Spain). To bridge this gap, the Catalan Network of Smoke-free Hospitals launched a nationwide bottom-up strategy in Catalonia in 2007. The strategy relied on the creation of a working group of key professionals from various hospitals —the early adopters— based on Rogers’ theory of the Diffusion of Innovations. In 2016, the working group is composed of professionals from 17 hospitals (70.8% of all hospitals in the region with mental health inpatient units). Since 2007, tobacco control has improved in different areas such as increasing mental health professionals’ awareness of smoking, training professionals on smoking cessation interventions and achieving good compliance with the national smoking ban. The working group has produced and disseminated various materials, including clinical practice and best practice guidelines, implemented smoking cessation programmes and organised seminars and training sessions on smoking cessation measures in patients with mental illnesses. The next challenge is to ensure effective follow-up for smoking cessation after discharge. While some areas of tobacco control within these services still require significant improvement, the aforementioned initiative promotes successful tobacco control in these settings. 相似文献
5.
A major advance was made to reduce the side effects of cancer therapy via the elucidation of the tumor-specific lytic path “hyperploid progression-mediated death” targeting retinoblastoma (Rb) or p53-mutants defective in G1 DNA damage checkpoint. The genetic basis of human cancers was uncovered through the cloning of the tumor suppressor Rb gene. It encodes a nuclear DNA-binding protein whose self-interaction is regulated by cyclin-dependent kinases. A 3D-structure of Rb dimer is shown, confirming its multimeric status. Rb assumes a central role in cell cycle regulation and the “Rb pathway” is universally inactivated in human cancers. Hyperploidy refers to a state in which cells contain one or more extra chromosomes. Hyperploid progression occurs due to continued cell-cycling without cytokinesis in G1 checkpoint-defective cancer cells. The evidence for the triggering of hyperploid progression-mediated death in RB-mutant human retinoblastoma cells is shown. Hence, the very genetic mutation that predisposes to cancer can be exploited to induce lethality. The discovery helped to establish the principle of targeted cytotoxic cancer therapy at the mechanistic level. By triggering the lytic path, targeted therapy with tumor specificity at the genetic level can be developed. It sets the stage for systematically eliminating side effects for cytotoxic cancer therapy. 相似文献
6.
7.
8.
9.
10.