全文获取类型
收费全文 | 40315篇 |
免费 | 1854篇 |
国内免费 | 941篇 |
专业分类
耳鼻咽喉 | 183篇 |
儿科学 | 768篇 |
妇产科学 | 638篇 |
基础医学 | 5418篇 |
口腔科学 | 1044篇 |
临床医学 | 2990篇 |
内科学 | 6434篇 |
皮肤病学 | 525篇 |
神经病学 | 3188篇 |
特种医学 | 692篇 |
外国民族医学 | 11篇 |
外科学 | 3215篇 |
综合类 | 4419篇 |
现状与发展 | 3篇 |
一般理论 | 4篇 |
预防医学 | 2285篇 |
眼科学 | 628篇 |
药学 | 6644篇 |
10篇 | |
中国医学 | 2074篇 |
肿瘤学 | 1937篇 |
出版年
2023年 | 440篇 |
2022年 | 684篇 |
2021年 | 1128篇 |
2020年 | 1246篇 |
2019年 | 1780篇 |
2018年 | 1706篇 |
2017年 | 1378篇 |
2016年 | 1192篇 |
2015年 | 1081篇 |
2014年 | 2440篇 |
2013年 | 3523篇 |
2012年 | 2764篇 |
2011年 | 2667篇 |
2010年 | 2031篇 |
2009年 | 1898篇 |
2008年 | 1638篇 |
2007年 | 1326篇 |
2006年 | 994篇 |
2005年 | 918篇 |
2004年 | 739篇 |
2003年 | 633篇 |
2002年 | 497篇 |
2001年 | 434篇 |
2000年 | 317篇 |
1999年 | 312篇 |
1998年 | 260篇 |
1997年 | 226篇 |
1996年 | 197篇 |
1995年 | 192篇 |
1994年 | 171篇 |
1993年 | 121篇 |
1992年 | 137篇 |
1991年 | 128篇 |
1990年 | 102篇 |
1989年 | 101篇 |
1988年 | 85篇 |
1987年 | 89篇 |
1985年 | 702篇 |
1984年 | 888篇 |
1983年 | 697篇 |
1982年 | 841篇 |
1981年 | 803篇 |
1980年 | 646篇 |
1979年 | 648篇 |
1978年 | 409篇 |
1977年 | 394篇 |
1976年 | 437篇 |
1975年 | 386篇 |
1974年 | 275篇 |
1973年 | 288篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
目的分析同型半胱氨酸(Hcy)、溶血磷脂酸(LPA)及转化生长因子-β1(TGF-β1)在创伤性骨折下肢静脉栓塞中的预测价值。方法选取2019年3月至2020年2月商丘市第一人民医院收治的104例创伤性骨折者(观察组),根据有无DVT:有DVT组33例,无DVT组71例;根据创伤严重程度:轻度组61例,重度组43例。另选取本院同期92例健康体检者设为对照组。比较不同人群、不同病情程度以及有无DVT者血浆Hcy、LPA及血清TGF-β1水平,分析Hcy、LPA及TGF-β1对DVT的预测价值。结果观察组Hcy、LPA及TGF-β1表达水平均明显高于对照组,差异均有统计学意义(P<0.05)。重度组Hcy、LPA及TGF-β1表达水平明显高于轻度组,差异均有统计学意义(P<0.05)。有DVT组者Hcy、LPA及TGF-β1表达水平明显高于无DVT组,差异均有统计学意义(P<0.05)。依据ROC曲线分析可知,Hcy+LPA+TGF-β1三者联合预测创伤性骨折后发生DVT敏感度和特异度分别为88.90%、8130%,明显高于三者单独检测(P<0.05)。结论Hcy、LPA及TGF-β1在创伤性骨折发生下肢静脉栓塞时水平均明显升高,三者联合检测对下肢静脉栓塞早期诊断有重要的临床价值。 相似文献
2.
3.
《中医科学杂志(英文)》2022,9(2):166-180
ObjectiveTo observe the relationship between the different stages of type 2 diabetes mellitus (T2DM) and the intestinal flora and verify its underlying mechanism.MethodsT2DM rats were generated by high-fat diet (HFD) combined with intraperitoneal streptozotocin (STZ) injection. The rats were divided into four groups: the control group (fed with normal feed for 1 month), the HFD group (fed with HFD for 1 month), the T2DM group (HFD combined with STZ and blood glucose ≥11.1 mM), and the unformed T2DM model (Un-mod) group (HFD combined with STZ and blood glucose <11.1 mM). Feces were collected, and bacterial communities in the fecal samples were analyzed by 16S rRNA gene sequencing. The content of short-chain fatty acids (SCFAs) in feces was measured by gas chromatography. Western blot and quantitative real-time polymerase chain reaction were used to detect the expression of G protein-coupled receptor 41 (GPR41) and GPR43.ResultsAt different stages of T2DM, the intestinal flora and SCFAs content of rats were significantly decreased (all P < .05). Our results indicated that g__Prevotella had a significant negative correlation, and g__Ruminococcus_torques_group and g__lachnoclastic had a significant positive correlation with blood glucose. The content of SCFAs, in particular acetate and butyrate, in rat feces of different stages of T2DM were significantly reduced, as well as GPR41 and GPR43 expression. The results in the Un-mod group were similar to the T2DM group, and the expression of GPR41 and GPR43 proteins were significantly higher than those in the T2DM group (both P < .001).ConclusionThe intestinal flora–SCFAs–GPR41/GPR43 network may be important in the development of T2DM. Decreasing blood glucose levels by regulating the intestinal flora may become a new therapeutic strategy for T2DM, which has very important clinical and social values. 相似文献
4.
《Journal of vascular and interventional radiology : JVIR》2022,33(10):1143-1150
PurposeTo report the 5-year results from the Pivotal Multicenter Trial of Ultrasound-Guided Percutaneous Arteriovenous Fistula (pAVF) Creation for Hemodialysis Access.Materials and MethodsThe retrospective review of 107 intent-to-treat (ITT) patients from the pivotal trial provided a long-term follow-up population (LTP) of 85 patients with a median follow-up duration of 50 months (range, 12–60 months). Data evaluated in the LTP group were fistula maturation and usage, secondary procedures, and complications. The Kaplan-Meier analysis of primary patency, assisted primary patency, cumulative patency, and functional patency (time from 2-needle cannulation to abandonment) were performed for the ITT population.ResultsIn the LTP, 99% (84 of 85) of fistulae were mature, with 99% (78 of 79) of patients requiring hemodialysis using their pAVF. Sustained fistula use (2-needle cannulation at the prescribed rate, 2 of 3 sessions) was achieved in 92% (78 of 85) of patients, with 7 patients not using their pAVF because they were not on dialysis (n = 4), were on peritoneal dialysis (n = 2), and refused to use fistula (n = 1). Fistula maintenance was required in 31.8% (27 of 85) of patients and included fistula dysfunction (21.2%), thrombosis (5.9%), cannulation injury (12.9%), and arm swelling (4.7%). The number of procedures performed per patient per year to maintain function and patency was 0.32 (91 of 288) for years 2–5. The cumulative patency rates were 89.5%, 88.4%, 88.4%, 85.6%, and 82.0% for years 1, 2, 3, 4, and 5, respectively. The functional patency was 91.8% at the end of the study. There were no major complications related to pAVF during the long-term follow-up.ConclusionsPercutaneous fistulae have provided clinically effective and durable access for hemodialysis with low complications. The continued use and evaluation of pAVF are warranted. 相似文献
5.
《Clinical breast cancer》2022,22(6):507-514
Breast cancer (BC) is a highly metastatic, pathological cancer that significantly affects women worldwide. The mortality rate of BC is related to its heterogeneity, aggressive phenotype, and metastasis. Recent studies have highlighted that the tumor microenvironment (TME) is critical for the interplay between metastasis mediators in BC. BC stem cells, tumor-derived exosomes, circulatory tumor cells (CTCs), and signaling pathways dynamically remodel the TME and promote metastasis. This review examines the cellular and molecular mechanisms governing the epithelial to mesenchymal transition (EMT) that facilitate metastasis. This review also discusses the role of cancer stem cells (CSCs), tumor-derived exosomes, and CTs in promoting BC metastasis. Furthermore, the review emphasizes major signaling pathways that mediate metastasis in BC. Finally, the interplay among CSCs, exosomes, and CTCs in mediating metastasis have been highlighted. Therefore, understanding the molecular cues that mediate the association of CSCs, exosomes, and CTCs in TME helps to optimize systemic therapy to target metastatic BC. 相似文献
6.
This commentary focuses on the emerging intersection between BMP/TGF-β signaling roles in nervous system function and the amyotrophic lateral sclerosis (ALS) disease state. Future research is critical to elucidate the molecular underpinnings of this intersection of the cellular processes disrupted in ALS and those influenced by BMP/TGF-β signaling, including synapse structure, neurotransmission, plasticity, and neuroinflammation. Such knowledge promises to inform us of ideal entry points for the targeted modulation of dysfunctional cellular processes in an effort to abrogate ALS pathologies. It is likely that different interventions are required, either at discrete points in disease progression, or across multiple dysfunctional processes which together lead to motor neuron degeneration and death. We discuss the challenging, but intriguing idea that modulation of the pleiotropic nature of BMP/TGF-β signaling could be advantageous, as a way to simultaneously treat defects in more than one cell process across different forms of ALS. 相似文献
7.
8.
The present study aims to shed new light on anti-aging effect of DL-β-hydroxybutyrate (βOHB) against hepatic cellular senescence induced by d-galactose or γ-irradiation. The rats divided into 6 groups. Group 1, control, group 2, exposed to γ-ray (5 GY), group 3, injected by d-galactose (150 mg/kg) daily for consecutive 6 weeks, which regarded to induce the aging, group 4, injected intraperitoneal by β-hydroxybutyrate (βOHB) (72.8 mg/kg) daily for consecutive 14 days, group 5, exposed to γ-ray then treated with βOHB daily for consecutive 14 days, group 6, injected daily with d-galactose for consecutive 6 weeks, then treated with βOHB daily at the last two weeks of d-galactose. Aspartate amino transferase (AST), alanine amino transferase (ALT), Insulin, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were estimated in serum. Moreover, protein expression of Microtubule-associated proteins 1A/1B light chain 3B (LC3-II/LC3-I) ratio, mechanistic target of rapamycin (mTOR), pAMPK, mRNA gene expression of 5′ AMP-activated protein kinase (AMPK), Nucleoporin p62 (p62), cyclin-dependent kinase inhibitor 1(P21CIP1), cyclin-dependent kinase inhibitor 2A (p16INK4a) and DNA fragmentation percentage were measured in liver tissue as a biomarker of cellular senescence. The results confirmed that βOHB modulated serum level of AST, ALT, insulin, IL-6 and TNF-α, protein expression of mTOR and LC3-II/LC3-I ratio, pAMPK and p62 in liver aging model induced by d-galactose or γ-irradiation. Histopathological examination results of liver tissue indicated coincidence with those recorded by molecular biochemical inspection. Taken together, these findings suggest that βOHB may be useful in combating hepatic cellular senescence induced by d-galactose or γ-irradiation via autophagy dependent mechanisms. 相似文献
9.
β-紫罗兰酮(β-Ionone,BI)是一类环化异戊二烯,广泛分布于水果和蔬菜中。BI具有多种生物活性,其抗癌活性是当前研究的热点,并可成为一种潜在的癌症化学预防剂。为更好地理解其抑制肿瘤方面的作用及其机制,本文对BI近年来研究进展进行简要地综述。 相似文献
10.