全文获取类型
收费全文 | 10103篇 |
免费 | 721篇 |
国内免费 | 963篇 |
专业分类
11787篇 |
出版年
2024年 | 21篇 |
2023年 | 151篇 |
2022年 | 375篇 |
2021年 | 639篇 |
2020年 | 374篇 |
2019年 | 480篇 |
2018年 | 472篇 |
2017年 | 323篇 |
2016年 | 455篇 |
2015年 | 704篇 |
2014年 | 822篇 |
2013年 | 802篇 |
2012年 | 943篇 |
2011年 | 879篇 |
2010年 | 519篇 |
2009年 | 474篇 |
2008年 | 515篇 |
2007年 | 447篇 |
2006年 | 360篇 |
2005年 | 293篇 |
2004年 | 250篇 |
2003年 | 253篇 |
2002年 | 232篇 |
2001年 | 163篇 |
2000年 | 124篇 |
1999年 | 139篇 |
1998年 | 83篇 |
1997年 | 72篇 |
1996年 | 69篇 |
1995年 | 54篇 |
1994年 | 41篇 |
1993年 | 31篇 |
1992年 | 48篇 |
1991年 | 27篇 |
1990年 | 27篇 |
1989年 | 40篇 |
1988年 | 16篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 25篇 |
1984年 | 8篇 |
1983年 | 11篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1974年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
122.
Biological functions of microRNAs: a review 总被引:1,自引:0,他引:1
123.
Xin Liu Zhi Jing Wen-Qing Jia Shu-Qing Wang Wei-Ren Xu 《Journal of biomolecular structure & dynamics》2018,36(11):2988-3002
PPARα and PPARγ have been the most widely studied Peroxisome proliferator-activated receptor (PPAR) subtypes due to their important roles in regulating glucose, lipids, and cholesterol metabolism. By combining the lowering serum triglyceride levels benefit of PPARα agonists (such as fibrates) with the glycemic advantages of the PPARγ agonists (such as TZD), the dual PPAR agonists approach can both improve the metabolic effects and minimize the side effects caused by either agent alone, and hence, has become a promising strategy for designing effective drugs against type-2 diabetes. In this study, by means of virtual screening, ADMET prediction and molecular dynamics (MD) simulations techniques, one compound-ASN15761007 with high binding score, low toxicity were gained. It was observed by MD simulations that ASN15761007 not only possessed the same function as AZ242 did in activating PPARα and BRL did in activating PPARγ, but also had more favorable conformation for binding to the two receptors. Our results provided an approach to rapidly produce novel PPARα/γ dual agonists which might be a potential lead compound to develop against insulin resistance and hyperlipidemia. 相似文献
124.
本实验用胆固醇粉喂家兔,造成实验性高脂血症,活体观察球结膜微循环的形态、流态及血管周围状态等15项指标,并用球结膜微循环综合定量评价方法计算了综合积分值。处死后取球结膜进行组织学检查。结果表明:高脂血症家兔球结膜微循环有明显改变,主要为微血管形态异常、血流减慢、红细胞聚集、白微栓、静脉壁上有白色斑块等改变。球结膜微循环综合积分值明显增加,高于实验前。球结膜组织学检查发现上皮层下有泡沫细胞、血管壁增厚、有空泡、静脉内有血栓。虹膜睫状体内除有多数泡沫细胞外,还有胆固醇的菱形结晶。上述改变表明,高脂血症兔球结膜微循环有明显改变。血液有高凝、高聚倾向。黑茶中的茶色素有抗凝、抑制血小板聚集、促进纤溶等作用,口服黑茶可改善高脂血症兔球结膜微循环障碍。 相似文献
125.
Makawi Ahmed Abdalhamid Osman Yu‐Jing Sun Rui‐Jia Li Hui Lin Dong‐Mei Zeng Xin‐Yu Chen Dongfang He Hui‐Wei Feng Zhao Yang Jin Wang Chaodong Wu Min Cui Jin‐Peng Sun Yuqing Huo Xiao Yu 《Journal of cellular and molecular medicine》2019,23(7):4653-4665
Severe reduction in the β‐cell number (collectively known as the β‐cell mass) contributes to the development of both type 1 and type 2 diabetes. Recent pharmacological studies have suggested that increased pancreatic β‐cell proliferation could be due to specific inhibition of adenosine kinase (ADK). However, genetic evidence for the function of pancreatic β‐cell ADK under physiological conditions or in a pathological context is still lacking. In this study, we crossed mice carrying LoxP‐flanked Adk gene with Ins2‐Cre mice to acquire pancreatic β ‐cell ADK deficiency (Ins2‐Cre±Adkfl/fl) mice. Our results revealed that Ins2‐Cre+/‐Adkfl/fl mice showed improved glucose metabolism and β‐cell mass in younger mice, but showed normal activity in adult mice. Moreover, Ins2‐Cre±Adkfl/fl mice were more resistant to streptozotocin (STZ) induced hyperglycaemia and pancreatic β‐cell damage in adult mice. In conclusion, we found that ADK negatively regulates β‐cell replication in young mice as well as under pathological conditions, such as STZ induced pancreatic β‐cell damage. Our study provided genetic evidence that specific inhibition of pancreatic β‐cell ADK has potential for anti‐diabetic therapy. 相似文献
126.
127.
Cancer occurs when cells acquire genomic instability and inflammation, produce abnormal levels of epigenetic factors/proteins and tumor suppressors, reprogram the energy metabolism and evade immune destruction, leading to the disruption of cell cycle/normal growth. An early event in carcinogenesis is loss of polarity and detachment from the natural basement membrane, allowing cells to form distinct three-dimensional (3D) structures that interact with each other and with the surrounding microenvironment. Although valuable information has been accumulated from traditional in vitro studies in which cells are grown on flat and hard plastic surfaces (2D culture), this culture condition does not reflect the essential features of tumor tissues. Further, fundamental understanding of cancer metastasis cannot be obtained readily from 2D studies because they lack the complex and dynamic cell–cell communications and cell–matrix interactions that occur during cancer metastasis. These shortcomings, along with lack of spatial depth and cell connectivity, limit the applicability of 2D cultures to accurate testing of pharmacologically active compounds, free or sequestered in nanoparticles. To recapitulate features of native tumor microenvironments, various biomimetic 3D tumor models have been developed to incorporate cancer and stromal cells, relevant matrix components, and biochemical and biophysical cues, into one spatially and temporally integrated system. In this article, we review recent advances in creating 3D tumor models employing tissue engineering principles. We then evaluate the utilities of these novel models for the testing of anticancer drugs and their delivery systems. We highlight the profound differences in responses from 3D in vitro tumors and conventional monolayer cultures. Overall, strategic integration of biological principles and engineering approaches will both improve understanding of tumor progression and invasion and support discovery of more personalized first line treatments for cancer patients. 相似文献
128.
129.
Zhaowei Meng Shanshan Lou Jian Tan Qiang Jia Rongxiu Zheng Geli Liu Mei Zhu Qing He Dong Li 《PloS one》2014,9(4)
Purpose
To assess scintigraphic pattern, clinical indication and relevance of dual ectopic thyroid tissue (ETT). Literature is reviewed for such cases.Methods
In this 5-year retrospective study, we reviewed all thyroid scintigraphies in our data base. Patients diagnosed with suspected ETT were identified. Literature is reviewed. Statistics were done by one-way analysis of variance and least significant difference test.Results
From 11905 thyroid scintigraphies during the 5-year period, we retrieved 121 patients eligible for analysis. The top two indications were assessing a palpable front neck mass to determine whether it was an ETT, and primary hypothyroidism. Patients were divided into 3 groups. Group 1 with single ETT (83 cases); group 2 with dual ETT (6 cases) and group 3 with athyroid (32 cases). Age and thyroid hormones were highest in group 2, and lowest in group 3. Thyrotropin was highest in group 3, and lowest in group 2. Thyroxine was given to hypothyroid patients, while no surgery was performed. There were 42 published cases with dual ETT, most of whom were under 30 years old. 38.10% of them were euthyroid, 33.33% hypothyroid, and 21.43% subclinical hypothyroid. Most frequent ectopic positions included lingual (33.73%), sublingual (27.71%) and subhyoid (22.89%).Conclusions
In our cohort, incidence of dual ETT was 0.05% if the denominator was total number of thyroid scintigraphies. The incidence was 4.96% if the denominator was the number of patients with suspected ETT. Important clinical indication is a front neck palpable mass suggestive of an ETT. Important clinical relevance of recognizing the dual ETT pattern is to avoid inappropriate surgery. After reviewing all published cases, we find dual ETT is often seen in young patients. Most of such patients are euthyroid or mildly hypothyroid. Thyroid ectopia often resides in lingual, sublingual and subhyoid areas. 相似文献130.
Biological Trace Element Research - Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus, presented as a major teratogenic cause worldwide. This study discussed... 相似文献