全文获取类型
收费全文 | 13500篇 |
免费 | 1093篇 |
国内免费 | 2篇 |
专业分类
14595篇 |
出版年
2023年 | 70篇 |
2022年 | 158篇 |
2021年 | 274篇 |
2020年 | 161篇 |
2019年 | 192篇 |
2018年 | 261篇 |
2017年 | 255篇 |
2016年 | 416篇 |
2015年 | 667篇 |
2014年 | 770篇 |
2013年 | 927篇 |
2012年 | 1263篇 |
2011年 | 1166篇 |
2010年 | 702篇 |
2009年 | 626篇 |
2008年 | 898篇 |
2007年 | 932篇 |
2006年 | 784篇 |
2005年 | 767篇 |
2004年 | 672篇 |
2003年 | 648篇 |
2002年 | 641篇 |
2001年 | 118篇 |
2000年 | 85篇 |
1999年 | 105篇 |
1998年 | 149篇 |
1997年 | 89篇 |
1996年 | 77篇 |
1995年 | 72篇 |
1994年 | 73篇 |
1993年 | 76篇 |
1992年 | 53篇 |
1991年 | 56篇 |
1990年 | 45篇 |
1989年 | 30篇 |
1988年 | 26篇 |
1987年 | 25篇 |
1986年 | 26篇 |
1985年 | 17篇 |
1984年 | 22篇 |
1983年 | 19篇 |
1982年 | 9篇 |
1981年 | 21篇 |
1980年 | 16篇 |
1979年 | 13篇 |
1978年 | 16篇 |
1975年 | 9篇 |
1973年 | 9篇 |
1971年 | 13篇 |
1966年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Elisabeth J. Leehr Kathrin Schag Amelie Brinkmann Ann-Christine Ehlis Andreas J. Fallgatter Stephan Zipfel Katrin E. Giel Thomas Dresler 《PloS one》2016,11(4)
ObjectiveFood stimuli are omnipresent and naturally primary reinforcing stimuli. One explanation for the intake of high amounts of food in binge eating disorder (BED) is a deviant valuation process. Valuation of food stimuli is supposed to influence approach or avoidance behaviour towards food. Focusing on self-reported and indirect (facial electromyography) valuation process, motivational aspects in the processing of food stimuli were investigated.MethodsWe compared an overweight sample with BED (BED+) with an overweight sample without BED (BED-) and with normal weight controls (NWC) regarding their self-reported and indirect (via facial electromyography) valuation of food versus non-food stimuli.ResultsRegarding the self-reported valuation, the BED+ sample showed a significantly stronger food-bias compared to the BED- sample, as food stimuli were rated as significantly more positive than the non-food stimuli in the BED+ sample. This self-reported valuation pattern could not be displayed in the indirect valuation. Food stimuli evoked negative indirect valuation in all groups. The BED+ sample showed the plainest approach-avoidance conflict marked by a diverging self-reported (positive) and indirect (negative) valuation of food stimuli.ConclusionsBED+ showed a deviant self-reported valuation of food as compared to BED-. The valuation process of the BED+ sample seems to be characterized by a motivational ambivalence. This ambivalence should be subject of further studies and may be of potential use for therapeutic interventions. 相似文献
942.
Marion Rother Erik Gonzalez Ana Rita Teixeira da Costa Lea Wask Isabella Gravenstein Matteo Pardo Matthias Pietzke Rajendra Kumar Gurumurthy Jörg Angermann Robert Laudeley Silke Glage Michael Meyer Cindrilla Chumduri Stefan Kempa Klaus Dinkel Anke Unger Bert Klebl Andreas Klos Thomas F. Meyer 《Cell host & microbe》2018,23(5):661-671.e8
943.
944.
McAndrews Ryan S. Eich Andreas Ford Amanda K. Bejarano Sonia Lal Ronal R. Ferse Sebastian C. A. 《Coral reefs (Online)》2019,38(3):431-441
Coral Reefs - Epilithic algae are a ubiquitous component of coral reefs. Components of the epilithic algal matrix (EAM) can have a significant influence on coral settlement and benthic feeding by... 相似文献
945.
Marg A Shan Y Meyer T Meissner T Brandenburg M Vinkemeier U 《The Journal of cell biology》2004,165(6):823-833
Interferon stimulation of cells leads to the tyrosine phosphorylation of latent Stat1 and subsequent transient accumulation in the nucleus that requires canonical transport factors. However, the mechanisms that control the predominantly cytoplasmic localization in unstimulated cells have not been resolved. We uncovered that constitutive energy- and transport factor-independent nucleocytoplasmic shuttling is a property of unphosphorylated Stat1, Stat3, and Stat5. The NH(2)- and COOH-terminal Stat domains are generally dispensable, whereas alkylation of a single cysteine residue blocked cytokine-independent nuclear translocation and thus implicated the linker domain into the cycling of Stat1. It is revealed that constitutive nucleocytoplasmic shuttling of Stat1 is mediated by direct interactions with the FG repeat regions of nucleoporin 153 and nucleoporin 214 of the nuclear pore. Concurrent active nuclear export by CRM1 created a nucleocytoplasmic Stat1 concentration gradient that is significantly reduced by the blocking of energy-requiring translocation mechanisms or the specific inactivation of CRM1. Thus, we propose that two independent translocation pathways cooperate to determine the steady-state distribution of Stat1. 相似文献
946.
Tanja Lucas Karim Benihoud Frédéric Vigant Christoph Q. Andreas Schmidt Max G. Bachem Thomas Simmet Stefan Kochanek 《PloS one》2015,10(2)
Primary pancreatic carcinoma has an unfavourable prognosis and standard treatment strategies mostly fail in advanced cases. Virotherapy might overcome this resistance to current treatment modalities. However, data from clinical studies with oncolytic viruses, including replicating adenoviral (Ad) vectors, have shown only limited activity against pancreatic cancer and other carcinomas. Since pancreatic carcinomas have a complex tumor architecture and frequently a strong stromal compartment consisting of non-neoplastic cell types (mainly pancreatic stellate cells = hPSCs) and extracellular matrix, it is not surprising that Ad vectors replicating in neoplastic cells will likely fail to eradicate this aggressive tumor type. Because the TGFβ receptor (TGFBR) is expressed on both neoplastic cells and hPSCs we inserted the TGFBR targeting peptide CKS17 into the hypervariable region 5 (HVR5) of the capsid protein hexon with the aim to generate a replicating Ad vector with improved activity in complex tumors. We demonstrated increased transduction of both pancreatic cancer cell lines and of hPSCs and enhanced cytotoxicity in co-cultures of both cell types. Surface plasmon resonance analysis demonstrated decreased binding of coagulation factor X to CKS17-modified Ad particles and in vivo biodistribution studies performed in mice indicated decreased transduction of hepatocytes. Thus, to increase activity of replicating Ad vectors we propose to relax tumor cell selectivity by genetic hexon-mediated targeting to the TGFBR (or other receptors present on both neoplastic and non-neoplastic cells within the tumor) to enable replication also in the stromal cell compartment of tumors, while abolishing hepatocyte transduction, and thereby increasing safety. 相似文献
947.
948.
Haubold M Weise A Stephan H Dünker N 《International journal of biological sciences》2010,6(7):700-715
Bone morphogenetic proteins (BMPs) - expressed in the developing retina - are known to be involved in the regulation of cell proliferation and apoptosis in several tumor entities. The objective of this study was to determine the role of the BMP4 pathway in retinoblastoma cells, which are absent in a functional retinoblastoma (RB1) gene. BMP receptors were detected in all retinoblastoma cell lines investigated. A correct transmission of BMP signaling via the Smad1/5/8 pathway could be demonstrated in WERI-Rb1 retinoblastoma cells and application of recombinant human BMP4 resulted in an increase in apoptosis, which to a large extend is caspase independent. Cell proliferation was not affected by BMP4 signaling, although the pRb-related proteins p107 and p130, contributing to the regulation of the same genes, are still expressed. WERI-Rb1 cells exhibit elevated endogenous levels of p21(CIP1) and p53, but we did not detect any increase in p53, p21(CIP1)or p27(KIP1) expression levels. Id proteins became, however, strongly up-regulated upon exogenous BMP4 treatment. Thus, RB1 loss in WERI-Rb1 cells is obviously not compensated for by pRb-independent (e.g. p53-dependent) cell cycle control mechanisms, preventing an anti-proliferative response to BMP4, which normally induces cell cycle arrest. 相似文献
949.
éva Borbély Zsófia Hajna Katalin Sándor László Kereskai István Tóth Erika Pintér Péter Nagy János Szolcsányi John Quinn Andreas Zimmer James Stewart Christopher Paige Alexandra Berger Zsuzsanna Helyes 《PloS one》2013,8(4)
Objective
Substance P, encoded by the Tac1 gene, is involved in neurogenic inflammation and hyperalgesia via neurokinin 1 (NK1) receptor activation. Its non-neuronal counterpart, hemokinin-1, which is derived from the Tac4 gene, is also a potent NK1 agonist. Although hemokinin-1 has been described as a tachykinin of distinct origin and function compared to SP, its role in inflammatory and pain processes has not yet been elucidated in such detail. In this study, we analysed the involvement of tachykinins derived from the Tac1 and Tac4 genes, as well as the NK1 receptor in chronic arthritis of the mouse.Methods
Complete Freund’s Adjuvant was injected intraplantarly and into the tail of Tac1−/−, Tac4−/−, Tacr1−/− (NK1 receptor deficient) and Tac1−/−/Tac4−/− mice. Paw volume was measured by plethysmometry and mechanosensitivity using dynamic plantar aesthesiometry over a time period of 21 days. Semiquantitative histopathological scoring and ELISA measurement of IL-1β concentrations of the tibiotarsal joints were performed.Results
Mechanical hyperalgesia was significantly reduced from day 11 in Tac4−/− and Tacr1−/− animals, while paw swelling was not altered in any strain. Inflammatory histopathological alterations (synovial swelling, leukocyte infiltration, cartilage destruction, bone damage) and IL-1β concentration in the joint homogenates were significantly smaller in Tac4−/− and Tac1−/−/Tac4−/− mice.Conclusions
Hemokinin-1, but not substance P increases inflammation and hyperalgesia in the late phase of adjuvant-induced arthritis. While NK1 receptors mediate its antihyperalgesic actions, the involvement of another receptor in histopathological changes and IL-1β production is suggested. 相似文献950.
Konstantin Schneider Jens Olaf Krömer Christoph Wittmann Isabel Alves-Rodrigues Andreas Meyerhans Juana Diez Elmar Heinzle 《Microbial cell factories》2009,8(1):12-14