全文获取类型
收费全文 | 15487篇 |
免费 | 1450篇 |
国内免费 | 1719篇 |
专业分类
18656篇 |
出版年
2024年 | 48篇 |
2023年 | 210篇 |
2022年 | 468篇 |
2021年 | 677篇 |
2020年 | 521篇 |
2019年 | 696篇 |
2018年 | 681篇 |
2017年 | 495篇 |
2016年 | 686篇 |
2015年 | 1018篇 |
2014年 | 1230篇 |
2013年 | 1211篇 |
2012年 | 1525篇 |
2011年 | 1429篇 |
2010年 | 894篇 |
2009年 | 790篇 |
2008年 | 993篇 |
2007年 | 905篇 |
2006年 | 737篇 |
2005年 | 661篇 |
2004年 | 547篇 |
2003年 | 490篇 |
2002年 | 472篇 |
2001年 | 221篇 |
2000年 | 189篇 |
1999年 | 186篇 |
1998年 | 134篇 |
1997年 | 95篇 |
1996年 | 61篇 |
1995年 | 52篇 |
1994年 | 54篇 |
1993年 | 32篇 |
1992年 | 43篇 |
1991年 | 31篇 |
1990年 | 32篇 |
1989年 | 21篇 |
1988年 | 16篇 |
1987年 | 12篇 |
1986年 | 14篇 |
1985年 | 11篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1979年 | 5篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1970年 | 3篇 |
1966年 | 3篇 |
1965年 | 3篇 |
1964年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
941.
Jae-Won Hyun Su-Hyun Kim In Hye Jeong Suk-Won Ahn So-Young Huh Min Su Park Young In Eom In Soo Joo Joong-Yang Cho Eun Bin Cho Ju-Hong Min Byoung Joon Kim Nam-Hee Kim Jeeyoung Oh Kee Duk Park Ho Jin Kim 《PloS one》2015,10(5)
Objectives
Early identification of suboptimal responders to multiple sclerosis (MS) treatment is critical for optimizing therapeutic decisions. The Rio score (RS) and modified Rio score (MRS) were developed to discriminate the responses to interferon-beta (IFNB) treatment in MS patients. This study was performed to evaluate the utility of RS and MRS in daily clinical practice in Korea.Methods
This was a real-world setting, multicenter, retrospective study of MS patients treated with IFNB from 10 hospitals in Korea. We investigated whether the RS and MRS at the early stage of IFNB therapy could predict treatment responses over 3 years. Suboptimal treatment responses at 3 years were defined as the presence of clinical relapse and/or EDSS progression and/or patients who had been treated with INFB for at least for 1 year and therapy was switched due to perceived treatment failure during the 2 years of follow-up.Results
Seventy patients (50 females and 20 males) were enrolled; 92% (12/13) of patients with high RS and 86% (12/14) of patients with high MRS (score 2 or 3) were suboptimal responders, whereas 93% (53/57) of patients with low RS and 93% (52/56) patients with low MRS (score 0 or 1) showed optimal responses. New active lesions on MRI with clinical relapse in high RS and MRS were the most common combination in suboptimal responders.Conclusions
We confirmed that RS and MRS at 6–15 months of IFNB therapy were useful for predicting poor responders over 3 years. 相似文献942.
Geon Ha Kim Seun Jeon Kiho Im Hunki Kwon Byung Hwa Lee Ga Young Kim Hana Jeong Noh Eul Han Sang Won Seo Hanna Cho Young Noh Sang Eon Park Hojeong Kim Jung Won Hwang Cindy W. Yoon Hee Jin Kim Byoung Seok Ye Ju Hee Chin Jung-Hyun Kim Mee Kyung Suh Jong Min Lee Sung Tae Kim Mun-Taek Choi Mun Sang Kim Kenneth M Heilman Jee Hyang Jeong Duk L. Na 《PloS one》2015,10(4)
The purpose of this study was to investigate if multi-domain cognitive training, especially robot-assisted training, alters cortical thickness in the brains of elderly participants. A controlled trial was conducted with 85 volunteers without cognitive impairment who were 60 years old or older. Participants were first randomized into two groups. One group consisted of 48 participants who would receive cognitive training and 37 who would not receive training. The cognitive training group was randomly divided into two groups, 24 who received traditional cognitive training and 24 who received robot-assisted cognitive training. The training for both groups consisted of daily 90-min-session, five days a week for a total of 12 weeks. The primary outcome was the changes in cortical thickness. When compared to the control group, both groups who underwent cognitive training demonstrated attenuation of age related cortical thinning in the frontotemporal association cortices. When the robot and the traditional interventions were directly compared, the robot group showed less cortical thinning in the anterior cingulate cortices. Our results suggest that cognitive training can mitigate age-associated structural brain changes in the elderly.
Trial Registration
ClnicalTrials.gov NCT01596205 相似文献943.
944.
Jaewon Shim Hee Jin Son Yiseul Kim Ki Hwa Kim Jung Tae Kim Hana Moon Min Jung Kim Takumi Misaka Mee-Ra Rhyu 《PloS one》2015,10(4)
Although the five basic taste qualities—sweet, sour, bitter, salty and umami—can be recognized by the respective gustatory system, interactions between these taste qualities are often experienced when food is consumed. Specifically, the umami taste has been investigated in terms of whether it enhances or reduces the other taste modalities. These studies, however, are based on individual perception and not on a molecular level. In this study we investigated umami-sweet taste interactions using umami compounds including monosodium glutamate (MSG), 5’-mononucleotides and glutamyl-dipeptides, glutamate-glutamate (Glu-Glu) and glutamate-aspartic acid (Glu-Asp), in human sweet taste receptor hT1R2/hT1R3-expressing cells. The sensitivity of sucrose to hT1R2/hT1R3 was significantly attenuated by MSG and umami active peptides but not by umami active nucleotides. Inhibition of sweet receptor activation by MSG and glutamyl peptides is obvious when sweet receptors are activated by sweeteners that target the extracellular domain (ECD) of T1R2, such as sucrose and acesulfame K, but not by cyclamate, which interact with the T1R3 transmembrane domain (TMD). Application of umami compounds with lactisole, inhibitory drugs that target T1R3, exerted a more severe inhibitory effect. The inhibition was also observed with F778A sweet receptor mutant, which have the defect in function of T1R3 TMD. These results suggest that umami peptides affect sweet taste receptors and this interaction prevents sweet receptor agonists from binding to the T1R2 ECD in an allosteric manner, not to the T1R3. This is the first report to define the interaction between umami and sweet taste receptors. 相似文献
945.
946.
947.
Nami Kim Hong Min Kim Eun Soo Lee Jung Ok Lee Hye Jeong Lee Soo Kyung Lee Ji Wook Moon Ji Hae Kim Joong Kwan Kim Su Jin Kim Sun Hwa Park Choon Hee Chung Hyeon Soo Kim 《PloS one》2015,10(3)
Dibenzoylmethane (DBM) has been shown to exert a variety of beneficial effects on human health. However, the mechanism of action is poorly understood. In this study, DBM increased phosphorylation of AMP-activated protein kinase (AMPK) and stimulated glucose uptake in a skeletal muscle cell line. Both knockdown of AMPK with siRNA and inhibition with AMPK inhibitor blocked DBM-induced glucose uptake. DBM increased the concentration of intracellular calcium and glucose uptake due to DBM was abolished by STO-609 (a calcium/calmodulin-dependent protein kinase inhibitor). DBM stimulated phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK), which was blocked by pretreatment with compound C, an AMPK inhibitor. The expression of glucose transporter type 4 (GLUT4) was increased by DBM. The translocation of GLUT4 to the plasma membrane was also increased by DBM in AMPK dependently. In addition, DBM suppressed weight gain and prevented fat accumulation in the liver and abdomen in mice fed a high-fat diet. In pre-adipocyte cells, DBM decreased the activity of acetyl-CoA carboxylase (ACC), the rate-limiting enzyme of fatty acid synthesis. Expression of the adipogenic gene, fatty acid synthase (FAS), was suppressed by DBM in an AMPK-dependent manner. These results showed that the beneficial metabolic effects of DBM might be due to regulation of glucose uptake via AMPK in skeletal muscle and inhibition of adipogenesis in pre-adipocytes. 相似文献
948.
Hanxiang Nie Qiaoyu Yang Guqin Zhang Ailing Wang Qing He Min Liu Ping Li Jiong Yang Yi Huang Xuhong Ding Hongying Yu Suping Hu 《PloS one》2015,10(4)
Background
Invariant natural killer T cells (iNKT cells) are a unique subset of T lymphocytes and are considered to play an important role in the development of allergic bronchial asthma. Recently, iNKT cells were shown to play an immunoregulatory role in CD4+ and CD8+ T cell-mediated adaptive immune response. Allergen-specific Th2 inflammatory responses are an important part of the adaptive immune response in asthma. However, the regulatory functions of the Th2 inflammatory response in asthma have not been studied in detail.Method
In this study, we have investigated the regulatory functions of iNKT cells on the Th2 inflammatory response in an ovalbumin (OVA)-induced murine model of asthma.Results
Our results demonstrate that α-Galactosylceramide (α-GalCer) administration activated iNKT cells but could not induce the Th2 inflammatory response in wild-type (WT) mice. In the OVA-induced asthma model, α-GalCer administration and adoptive transfer of iNKT cells significantly augmented the Th2 inflammatory responses, including elevated inflammatory cell infiltration in the lung and bronchoalveolar lavage fluid (BALF); increased levels of IL-4, IL-5, and IL-13 in the BALF and splenocyte culture supernatant; and increased serum levels of OVA-specific IgE and IgG1. In addition, the Th2 inflammatory response was reduced, but not completely abrogated in CD1d-/- mice immunized and challenged with OVA, compared with WT mice.Conclusion
These results suggest that iNKT cells may serve as an adjuvant to enhance Th2 inflammatory response in an OVA-induced murine model of asthma. 相似文献949.
Many species of Schisandraceae are used in traditional Chinese medicine and are faced with contamination and substitution risks due to inaccurate identification. Here, we investigated the discriminatory power of four commonly used DNA barcoding loci (ITS, trnH-psbA, matK, and rbcL) and corresponding multi-locus combinations for 135 individuals from 33 species of Schisandraceae, using distance-, tree-, similarity-, and character-based methods, at both the family level and the genus level. Our results showed that the two spacer regions (ITS and trnH-psbA) possess higher species-resolving power than the two coding regions (matK and rbcL). The degree of species resolution increased with most of the multi-locus combinations. Furthermore, our results implied that the best DNA barcode for the species discrimination at the family level might not always be the most suitable one at the genus level. Here we propose the combination of ITS+trnH-psbA+matK+rbcL as the most ideal DNA barcode for discriminating the medicinal plants of Schisandra and Kadsura, and the combination of ITS+trnH-psbA as the most suitable barcode for Illicium species. In addition, the closely related species Schisandra rubriflora Rehder & E. H. Wilson and Schisandra grandiflora Hook.f. & Thomson, were paraphyletic with each other on phylogenetic trees, suggesting that they should not be distinct species. Furthermore, the samples of these two species from the southern Hengduan Mountains region formed a distinct cluster that was separated from the samples of other regions, implying the presence of cryptic diversity. The feasibility of DNA barcodes for identification of geographical authenticity was also verified here. The database and paradigm that we provide in this study could be used as reference for the authentication of traditional Chinese medicinal plants utilizing DNA barcoding. 相似文献
950.
Jiandong Hu Ruipeng Chen Shun Wang Tingting Wang Yuanyuan Zhao Jianwei Li Xinran Hu Hao Liang Juanhua Zhu Xiaohui Sun Liuzheng Ma Min Jiang 《PloS one》2015,10(3)
A surface plasmon resonance (SPR) immunoassay with an immobilization of self-assembled molecular identification membrane for the detection of residual Clenbuterol Hydrochloride (CLB) in pork liver was systematically investigated and experimentally validated for its high performance. SPR immunoassay with a regular competitive inhibition assay cannot be directly verified to detect CLB residuals. In this study, the binding of Au film with mercaptopropionic acid was investigated using the known form of the strong S-Au covalent bonds formed by the chemical radical of the mercaptopropionic acid and the Au film. After that, the immunoglobulin IgG of swine (SwIgG-CLB) was bonded with the mercaptopropionic acid by covalent -CO-NH- amide bonding. The modified comprehensive analysis of how the membrane structure works was introduced together with the customized SPR bioanalyzer. In order to evaluate the performance of this biomembrane structure, the concentrations of CLB-contained solutions of 0 ng•mL-1, 10 ng•mL-1, 20 ng•mL-1, 33.3 ng•mL-1, and 40 ng•mL-1 were prepared by adding CLB reagents into the solutions of CLB antibody (Clenbuterol Hydrochloride Antibody, CLB-Ab), successively and then the response unit (RU) was measured individually. Using the data collected from the linear CCD array, the fitting curve was established with the R-Square value of 0.9929. Correspondingly, the recovery rate ranged from 88.48% to 103.21% was experimented and the limit of detection of CLB in 1.26 ng•mL-1 was obtained efficiently. It was concluded that the detection method associated with biomembrane properties is expected to contribute much to the determination of residual CLB in pork liver quantitatively by using the customized SPR bioanalyzer. 相似文献