全文获取类型
收费全文 | 3067篇 |
免费 | 191篇 |
专业分类
3258篇 |
出版年
2023年 | 8篇 |
2022年 | 21篇 |
2021年 | 32篇 |
2020年 | 20篇 |
2019年 | 35篇 |
2018年 | 48篇 |
2017年 | 49篇 |
2016年 | 71篇 |
2015年 | 108篇 |
2014年 | 143篇 |
2013年 | 168篇 |
2012年 | 213篇 |
2011年 | 214篇 |
2010年 | 147篇 |
2009年 | 144篇 |
2008年 | 234篇 |
2007年 | 195篇 |
2006年 | 207篇 |
2005年 | 209篇 |
2004年 | 207篇 |
2003年 | 157篇 |
2002年 | 186篇 |
2001年 | 26篇 |
2000年 | 25篇 |
1999年 | 31篇 |
1998年 | 39篇 |
1997年 | 30篇 |
1996年 | 32篇 |
1995年 | 15篇 |
1994年 | 20篇 |
1993年 | 20篇 |
1992年 | 16篇 |
1991年 | 10篇 |
1990年 | 13篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 12篇 |
1984年 | 17篇 |
1983年 | 19篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 11篇 |
1978年 | 5篇 |
1977年 | 11篇 |
1975年 | 6篇 |
1974年 | 8篇 |
1973年 | 6篇 |
排序方式: 共有3258条查询结果,搜索用时 10 毫秒
51.
Yuko Ishizaki Mitsue Maru Hirohiko Higashino Shoko Katsumoto Kyoko Egawa Yoshitoki Yanagimoto Teruyo Nagahama 《BioPsychoSocial medicine》2012,6(1):1-4
Background
Advances in medical science have enabled many children with chronic diseases to survive to adulthood. The transition of adult patients with childhood-onset chronic diseases from pediatric to adult healthcare systems has received attention in Europe and the United States. We conducted a questionnaire survey among 41 pediatricians at pediatric hospitals and 24 nurses specializing in adolescent care to compare the perception of transition of care from pediatric to adult healthcare services for such patients.Findings
Three-fourths of the pediatricians and all of the nurses reported that transition programs were necessary. A higher proportion of the nurses realized the necessity of transition and had already developed such programs. Both pediatricians and nurses reported that a network covering the transition from pediatric to adult healthcare services has not been established to date.Conclusions
It has been suggested that spreading the importance of a transition program among pediatricians and developing a pediatric-adult healthcare network would contribute to the biopsychosocial well-being of adult patients with childhood-onset chronic disease. 相似文献52.
Yoichiro Fujioka Shinya Nishide Toyoyuki Ose Tadaki Suzuki Izumi Kato Hideo Fukuhara Mari Fujioka Kosui Horiuchi Aya O. Satoh Prabha Nepal Sayaka Kashiwagi Jing Wang Mika Horiguchi Yuko Sato Sarad Paudel Asuka Nanbo Tadaaki Miyazaki Hideki Hasegawa Yusuke Ohba 《Cell host & microbe》2018,23(6):809-818.e5
53.
Po-sung Chu Hirotoshi Ebinuma Nobuhiro Nakamoto Kazuo Sugiyama Shingo Usui Yuko Wakayama Nobuhito Taniki Akihiro Yamaguchi Shunsuke Shiba Yoshiyuki Yamagishi Takaji Wakita Toshifumi Hibi Hidetsugu Saito Takanori Kanai 《PloS one》2015,10(5)
Hepatitis C virus (HCV) genotype 1 infections are significantly more difficult to eradicate with PEG-IFN/ribavirin therapy, compared to HCV genotype 2. The aim of this work is to investigate the difference of immunological impairments underlying this phenomenon. Pre-treatment NKG2D expression on peripheral CD56+CD3+ lymphocytes and CD56+CD3− NK cells from cases of chronic hepatitis C were analyzed and assessed by treatment effect. Two strains of HCV were used to co-incubate with immune cells in vitro. NKG2D expression on peripheral CD56+CD3+ lymphocytes, but not NK cells, was significantly impaired in genotype 1 infection, compared to genotype 2. When peripheral blood mononuclear cells from healthy donors were co-incubated with TNS2J1, a genotype 1b/2a chimera strain, or with JFH1, a genotype 2a strain, genotype-specific decrease of NKG2D on CD56+CD3+ lymphocytes, but not NK cells, was observed. Pre-treatment NKG2D expression on peripheral CD56+CD3+ lymphocytes significantly correlated with reduction in serum HCV RNA levels from week 0 to week 4, and predicted treatment response. Ex vivo stimulation of peripheral CD56+CD3+ lymphocytes showed NKG2D expression-correlated IFN-γ production. In conclusion, Decreased NKG2D expression on CD56+CD3+ lymphocytes in chronic HCV genotype 1 infection predicts inferior treatment response to PEG-IFN/ribavirin therapy compared to genotype 2. 相似文献
54.
Kyosuke Yamanishi Nobutaka Doe Miho Sumida Yuko Watanabe Momoko Yoshida Hideyuki Yamamoto Yunfeng Xu Wen Li Hiromichi Yamanishi Haruki Okamura Hisato Matsunaga 《PloS one》2015,10(3)
Major depressive disorder (MDD) is a common psychiatric disorder that involves marked disabilities in global functioning, anorexia, and severe medical comorbidities. MDD is associated with not only psychological and sociocultural problems, but also pervasive physical dysfunctions such as metabolic, neurobiological and immunological abnormalities. Nevertheless, the mechanisms underlying the interactions between these factors have yet to be determined in detail. The aim of the present study was to identify the molecular mechanisms responsible for the interactions between MDD and dysregulation of physiological homeostasis, including immunological function as well as lipid metabolism, coagulation, and hormonal activity in the brain. We generated depression-like behavior in mice using chronic mild stress (CMS) as a model of depression. We compared the gene expression profiles in the prefrontal cortex (PFC) of CMS and control mice using microarrays. We subsequently categorized genes using two web-based bioinformatics applications: Ingenuity Pathway Analysis and The Database for Annotation, Visualization, and Integrated Discovery. We then confirmed significant group-differences by analyzing mRNA and protein expression levels not only in the PFC, but also in the thalamus and hippocampus. These web tools revealed that hepatocyte nuclear factor 4 alpha (Hnf4a) may exert direct effects on various genes specifically associated with amine synthesis, such as genes involved in serotonin metabolism and related immunological functions. Moreover, these genes may influence lipid metabolism, coagulation, and hormonal activity. We also confirmed the significant effects of Hnf4a on both mRNA and protein expression levels in the brain. These results suggest that Hnf4a may have a critical influence on physiological homeostasis under depressive states, and may be associated with the mechanisms responsible for the interactions between MDD and the dysregulation of physiological homeostasis in humans. 相似文献
55.
56.
Two flavonoid glucosyltransferases from Petunia hybrida: molecular cloning,biochemical properties and developmentally regulated expression 总被引:4,自引:0,他引:4
Yamazaki M Yamagishi E Gong Z Fukuchi-Mizutani M Fukui Y Tanaka Y Kusumi T Yamaguchi M Saito K 《Plant molecular biology》2002,48(4):401-411
Two flavonoid glucosyltransferases, UDP-glucose:flavonoid 3-O-glucosyltransferase (3-GT) and UDP-glucose: anthocyanin 5-O-glucosyltransferase (5-GT), are responsible for the glucosylation of anthocyani(di)ns to produce stable molecules in the anthocyanin biosynthetic pathway. The cDNAs encoding 3-GT and 5-GT were isolated from Petunia hybrida by hybridization screening with heterologous probes. The cDNA clones of 3-GT, PGT8, and 5-GT, PH1, encode putative polypeptides of 448 and 468 amino acids, respectively. A phylogenetic tree based on amino acid sequences of the family of glycosyltransferases from various plants shows that PGT8 belongs to the 3-GT subfamily and PH1 belongs to the 5-GT subfamily. The function of isolated cDNAs was identified by the catalytic activities for 3-GT and 5-GT exhibited by the recombinant proteins produced in yeast. The recombinant PGT8 protein could convert not only anthocyanidins but also flavonols into the corresponding 3-O-glucosides. In contrast, the recombinant PH1 protein exhibited a strict substrate specificity towards anthocyanidin 3-acylrutinoside, comparing with other 5-GTs from Perilla frutescens and Verbena hybrida, which showed broad substrate specificities towards several anthocyanidin 3-glucosides. The mRNA expression of both 3-GT and 5-GT increased in the early developmental stages of P. hybrida flower, reaching the maximum at the stage before flower opening. Southern blotting analysis of genomic DNA indicates that both 3-GT and 5-GT genes exist in two copies in P. hybrida, respectively. The results are discussed in relation to the molecular evolution of flavonoid glycosyltransferases. 相似文献
57.
58.
Maeda S Sahara N Saito Y Murayama M Yoshiike Y Kim H Miyasaka T Murayama S Ikai A Takashima A 《Biochemistry》2007,46(12):3856-3861
Neurofibrillary tangles (NFTs) are pathological hallmarks of several neurodegenerative disorders, including Alzheimer's disease (AD). NFTs are composed of microtubule-binding protein tau, which assembles to form paired helical filaments (PHFs) and straight filaments. Here we show by atomic force microscopy that AD brain tissue and in vitro tau form granular and fibrillar tau aggregates. CD spectral analysis and immunostaining with conformation-dependent antibodies indicated that tau may undergo conformational changes during fibril formation. Enriched granules generated filaments, suggesting that granular tau aggregates may be an intermediate form of tau fibrils. The amount of granular tau aggregates was elevated in prefrontal cortex of Braak stage I cases compared to that of Braak stage 0 cases, suggesting that granular tau aggregation precedes PHF formation. Thus, granular tau aggregates may be a relevant marker for the early diagnosis of tauopathy. Reducing the level of these aggregates may be a promising therapy for tauopathies and for promoting healthy brain aging. 相似文献
59.
Suzuki Y Unno T Kobayashi M Nozawa A Sagesaka Y Kakuda T 《Bioscience, biotechnology, and biochemistry》2005,69(7):1288-1291
Tea has long been believed to be a healthy beverage, and its beneficial effects are almost all attributed to catechins. The effect of catechins on postprandial hypertriglyceridemia in rats was investigated in this study. A lipid emulsion administered orally to rats with (-)-epigallocatechin gallate at a dose of 100 mg/kg resulted in the increase in plasma triacylglycerol being significantly inhibited after 1 and 2 h compared to the case without (-)-epigallocatechin gallate. The effect of (-)-epigallocatechin was weaker than that of (-)-epigallocatechin gallate. A tea extract (THEA-FLAN 90S), mainly composed of catechins with a galloyl moiety, dose-dependently suppressed postprandial triacylglycerol after the administration of a lipid emulsion at doses of 50-200 mg/kg. The administration of the tea extract alone at a dose of 200 mg/kg had no effect on the plasma triacylglycerol level. These results strongly suggest that catechins with a galloyl moiety would be promising agents for suppressing dietary fat absorption through the small intestine. 相似文献
60.
Hashida S Yuzawa S Suzuki NN Fujioka Y Takikawa T Sumimoto H Inagaki F Fujii H 《The Journal of biological chemistry》2004,279(25):26378-26386
The superoxide-producing phagocyte NADPH oxidase can be reconstituted in a cell-free system. The activity of NADPH oxidase is dependent on FAD, but the physiological status of FAD in the oxidase is not fully elucidated. To clarify the role of FAD in NADPH oxidase, FAD-free full-length recombinant p47(phox), p67(phox), p40(phox), and Rac were prepared, and the activity was reconstituted with these proteins and purified cytochrome b(558) (cyt b(558)) with different amounts of FAD. A remarkably high activity, over 100 micromol/s/micromol heme, was obtained in the oxidase with purified cyt b(558), ternary complex (p47-p67-p40(phox)), and Rac. From titration with FAD of the activity of NADPH oxidase reconstituted with purified FAD-devoid cyt b, the dissociation constant K(d) of FAD in cyt b(558) of reconstituted oxidase was estimated as nearly 1 nm. We also examined addition of FAD on the assembly process in reconstituted oxidase. The activity was remarkably enhanced when FAD was present during assembly process, and the efficacy of incorporating FAD into the vacant FAD site in purified cyt b(558) increased, compared when FAD was added after assembly processes. The absorption spectra of reconstituted oxidase under anaerobiosis showed that incorporation of FAD into cyt b(558) recovered electron flow from NADPH to heme. From both K(d) values of FAD and the amount of incorporated FAD in cyt b(558) of reconstituted oxidase, in combination with spectra, we propose the model in which the K(d) values of FAD in cyt b(558) is changeable after activation and FAD binding works as a switch to regulate electron transfer in NADPH oxidase. 相似文献