全文获取类型
收费全文 | 9457篇 |
免费 | 734篇 |
国内免费 | 854篇 |
出版年
2024年 | 14篇 |
2023年 | 115篇 |
2022年 | 270篇 |
2021年 | 523篇 |
2020年 | 317篇 |
2019年 | 444篇 |
2018年 | 409篇 |
2017年 | 257篇 |
2016年 | 437篇 |
2015年 | 615篇 |
2014年 | 722篇 |
2013年 | 810篇 |
2012年 | 925篇 |
2011年 | 803篇 |
2010年 | 465篇 |
2009年 | 468篇 |
2008年 | 493篇 |
2007年 | 426篇 |
2006年 | 379篇 |
2005年 | 274篇 |
2004年 | 265篇 |
2003年 | 222篇 |
2002年 | 156篇 |
2001年 | 137篇 |
2000年 | 128篇 |
1999年 | 109篇 |
1998年 | 107篇 |
1997年 | 95篇 |
1996年 | 85篇 |
1995年 | 74篇 |
1994年 | 68篇 |
1993年 | 46篇 |
1992年 | 78篇 |
1991年 | 48篇 |
1990年 | 33篇 |
1989年 | 37篇 |
1988年 | 23篇 |
1987年 | 26篇 |
1986年 | 26篇 |
1985年 | 24篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 9篇 |
1976年 | 4篇 |
1973年 | 5篇 |
1971年 | 4篇 |
1968年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
Jianli Liu Siqi Tian Mingyang Fu Yin He Hui Yu Xiangyu Cao Yiyang Cao Hanyuan Xu 《化学与生物多样性》2020,17(2)
Anthocyanins (AC) from Coreopsis tinctoria possesses strong antioxidant properties, while the effects of AC on cells damage induced by reactive oxygen species (ROS) in diabetes mellitus diseases progression have not been reported. The present study was carried out to evaluate the protective property of AC against cellular oxidative stress with an experimental model, H2O2‐exposed MIN6 cells. AC could reverse the decrease of cell viability induced by H2O2 and efficiently suppressed cellular ROS production and cell apoptosis. In addition, Real‐time PCR and Western blot analyses indicated that AC could protect MIN6 cells against oxidative injury through increasing the translocation of Nrf2 into nuclear, decreasing the phosphorylation level of p38 and up‐regulating the protein expression of antioxidant enzyme (SOD1, SOD2 and CAT). Thus, this study provides evidence to support the beneficial effect of AC in inhibiting MIN6 cells from H2O2‐induced oxidative injury. 相似文献
102.
Xi Jin Tianhai Lin Guang Yang Huawei Cai Bo Tang Xinyang Liao Huifang Li Xiaoting Chen Lina Gong Hang Xu Yi Sun Ping Tan Jianqiong Yin Hongwen Ma Jianzhong Ai Kunjie Wang Qiang Wei Lu Yang Hong Li 《Journal of cellular and molecular medicine》2020,24(9):5082-5096
Benign prostatic hyperplasia (BPH) occurs most commonly among older men, often accompanied by chronic tissue inflammation. Although its aetiology remains unclear, autoimmune dysregulation may contribute to BPH. Regulatory T cells (Tregs) prevent autoimmune responses and maintain immune homeostasis. In this study, we aimed to investigate Tregs frequency, phenotype, and function in BPH patients and to evaluate adoptive transfer Tregs for immunotherapy in mice with BPH via CD39. Prostate specimens and peripheral blood from BPH patients were used to investigate Treg subsets, phenotype and Treg‐associated cytokine production. Sorted CD39+/? Tregs from healthy mice were adoptively transferred into mice before or after testosterone propionate administration. The Tregs percentage in peripheral blood from BPH patients was attenuated, exhibiting low Foxp3 and CD39 expression with low levels of serum IL‐10, IL‐35 and TGF‐β. Immunohistochemistry revealed Foxp3+ cells were significantly diminished in BPH prostate with severe inflammatory. Although the Tregs subset was comprised of more effector/memory Tregs, CD39 was still down‐regulated on effector/memory Tregs in BPH patients. Before or after testosterone propionate administration, no alterations of BPH symptoms were observed due to CD39‐ Tregs in mice, however, CD39+Tregs existed more potency than Tregs to regulate prostatic hyperplasia and inhibit inflammation by decreasing IL‐1β and PSA secretion, and increasing IL‐10 and TGF‐β secretion. Furthermore, adoptive transfer with functional Tregs not only improved prostate hyperplasia but also regulated muscle cell proliferation in bladder. Adoptive transfer with Tregs may provide a novel method for the prevention and treatment of BPH clinically. 相似文献
103.
Lei Zhang Yuan Zhang Sheng Xue Han Ding Yu Wang Hongzhao Qi Yin Wang Wenjie Zhu Peifeng Li 《Journal of cellular and molecular medicine》2020,24(1):1146-1150
Coronary artery disease (CAD) is one of the biggest threats to human life. Circulating microRNAs (miRNAs) have been reported to be linked to the pathogenesis of CAD, indicating the possible role in CAD diagnosis. The present study aimed to explore the expression profile of plasma miRNAs and estimate their value in diagnosis for CAD. 67 Non‐CAD control subjects and 88 CAD patients were enrolled. We conducted careful evaluation by RT‐PCR analysis, Spearman rank correlation coefficients analysis, Receiver Operating Characteristic (ROC) curves analysis and so on. The plasma levels of six miRNAs known to be related to CAD were measured and three of them showed obvious expression change. Circulating miR‐29a‐3p, miR‐574‐3p and miR‐574‐5p were all significantly increased. ROC analysis revealed the probability of the three miRNAs as biomarkers with AUCs (areas under the ROC curve) of 0.830, 0.792 and 0.789, respectively. They were significantly correlated with each other in CAD patients, suggesting the possibility of joint diagnosis. The combined AUC was 0.915, much higher than each single miRNA. Therefore, our study revealed three promising biomarkers for early diagnosis of CAD. The combination of these miRNAs may act more effectively than individual ones for CAD diagnosis. 相似文献
104.
105.
106.
Zhongkai Hao Qi Chen Wenrui Dai Yinjuan Ren Yin Zhou Jinlin Yang Sijie Xie Yanbin Shen Jihong Wu Wei Chen Guo Qin Xu 《Liver Transplantation》2020,10(10)
Developing a titanium dioxide (TiO2)‐based anode with superior high‐rate capability and long‐term cycling stability is important for efficient energy storage. Herein, a simple one‐step approach for fabricating blue TiO2 nanoparticles with oxygen vacancies is reported. Oxygen vacancies can enlarge lattice spaces, lower charge transfer resistance, and provide more active sites in TiO2 lattices. As a result, this blue TiO2 electrode exhibits a highly reversible capacity of 50 mAh g?1 at 100 C (16 800 mA g?1) even after 10 000 cycles, which is attributable to the combination of surface capacitive process and remarkable diffusion‐controlled insertion revealed by the kinetic analysis. The strategy of employing oxygen‐deficient nanoparticles may be extended to the design of other robust semiconductor materials as electrodes for energy storage. 相似文献
107.
108.
Wang Lixia Zhu Fan Yang Huansheng Li Jianzhong Li Yali Ding Xueqin Xiong Xia Ji Fengjie Zhou Hanlin Yin Yulong 《中国科学:生命科学英文版》2020,63(2):259-268
Epidermal growth factor(EGF) has been shown to improve piglet intestinal morphology and epithelial recovery. In an attempt to further understand the mechanisms behind these improvements, this study tested the hypothesis that dietary EGF may affect intestinal morphology by stimulating the proliferation and differentiation of enterocytes in weaning piglets. In piglets receiving200 μg kg–1 EGF, crypt depth and villus height increased(P0.05). Adding 400 μg kg–1 EGF increased villus height-to-crypt depth ratio(P0.05), but reduced crypt depth(P0.05). Dietary supplementation with 200 μg kg–1 EGF significantly increased the number of Ki67-positive cells(P0.01) and tended to increase the mRNA level of proliferating cell nuclear antigen(P0.10).However, this supplementation decreased the expression level of intestinal fatty acid-binding protein(P0.05). Piglets fed with400 μg kg–1 EGF had an increased mRNA level of intestinal alkaline phosphatase(P0.05). The phosphorylation of m TOR(mammalian target of rapamycin) was observed in the 200 μg kg–1 EGF group. These results suggest that dietary supplementation with a low level of EGF improved piglet intestinal morphology through stimulating the proliferation and differentiation of enterocytes, and the mTOR signaling pathway may partly be involved in this process. 相似文献
109.
110.
植物的无机元素分布特征对植物生理过程具有重要的指标作用, 可揭示营养物质分布、代谢途径及毒理耐受性等多种生命过程。用微区XRF技术测试样品中无机元素的分布, 具有原位无损、可进行较大面积样品连续成像分析以及前处理过程简单等诸多优势。将微区XRF技术应用于植物样品不同器官的无机元素分布检测, 旨在探讨该技术在植物样品测试中的仪器参数选择、样品前处理方法和数据后处理手段等对测试结果的影响。为得到可靠的实验结果, 对不同含水量的器官进行不同的前处理, 并比较不同驻留时间、测试腔体真空与否等仪器条件对测试结果的影响, 同时对数据处理方法进行探索, 包括对获得的数据进行图像叠加及对不同元素浓度比例进行半定量分析。研究结果表明, 微区XRF技术测试植物样品中无机元素分布具有一定的技术优势。 相似文献