全文获取类型
收费全文 | 10032篇 |
免费 | 746篇 |
国内免费 | 6篇 |
出版年
2021年 | 99篇 |
2020年 | 73篇 |
2019年 | 87篇 |
2018年 | 119篇 |
2017年 | 98篇 |
2016年 | 170篇 |
2015年 | 342篇 |
2014年 | 380篇 |
2013年 | 539篇 |
2012年 | 638篇 |
2011年 | 633篇 |
2010年 | 463篇 |
2009年 | 380篇 |
2008年 | 571篇 |
2007年 | 553篇 |
2006年 | 515篇 |
2005年 | 523篇 |
2004年 | 520篇 |
2003年 | 521篇 |
2002年 | 450篇 |
2001年 | 117篇 |
2000年 | 106篇 |
1999年 | 128篇 |
1998年 | 158篇 |
1997年 | 96篇 |
1996年 | 117篇 |
1995年 | 112篇 |
1994年 | 94篇 |
1993年 | 112篇 |
1992年 | 110篇 |
1991年 | 90篇 |
1990年 | 84篇 |
1989年 | 71篇 |
1988年 | 95篇 |
1987年 | 75篇 |
1986年 | 55篇 |
1985年 | 80篇 |
1984年 | 112篇 |
1983年 | 94篇 |
1982年 | 108篇 |
1981年 | 93篇 |
1980年 | 95篇 |
1979年 | 73篇 |
1978年 | 85篇 |
1977年 | 83篇 |
1976年 | 71篇 |
1975年 | 65篇 |
1974年 | 75篇 |
1973年 | 66篇 |
1972年 | 49篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
1.
Michael Fayon Annick Andrieux Imane Bara Muriel Rebola André Labbé Roger Marthan Patrick Berger 《PloS one》2015,10(3)
We compared the proliferation of neonatal and adult airway smooth muscle cells (ASMC) with no/moderate lung disease, in glucose- (energy production by glycolysis) or glucose-free medium (ATP production from mitochondrial oxidative phosphorylations only), in response to 10% fetal calf serum (FCS) and PDGF-AA. In the presence of glucose, cell counts were significantly greater in neonatal vs. adult ASMC. Similarly, neonatal ASMC DNA synthesis in 10% FCS and PDGF-AA, and [Ca2+]i responses in the presence of histamine were significantly enhanced vs. adults. In glucose-free medium, cell proliferation was preserved in neonatal cells, unlike in adult cells, with concomitant increased porin (an indicator of mitochondrial activity) protein expression. Compared to adults, stimulated neonatal human ASMC are in a rapid and robust proliferative phase and have the capacity to respond disproportionately under abnormal environmental conditions, through increased mitochondrial biogenesis and altered calcium homeostasis. 相似文献
2.
Keith M. Harris Jia-Jia Syu Owen D. Lello Y. L. Eileen Chew Christopher H. Willcox Roger H. M. Ho 《PloS one》2015,10(6)
There is considerable need for accurate suicide risk assessment for clinical, screening, and research purposes. This study applied the tripartite affect-behavior-cognition theory, the suicidal barometer model, classical test theory, and item response theory (IRT), to develop a brief self-report measure of suicide risk that is theoretically-grounded, reliable and valid. An initial survey (n = 359) employed an iterative process to an item pool, resulting in the six-item Suicidal Affect-Behavior-Cognition Scale (SABCS). Three additional studies tested the SABCS and a highly endorsed comparison measure. Studies included two online surveys (Ns = 1007, and 713), and one prospective clinical survey (n = 72; Time 2, n = 54). Factor analyses demonstrated SABCS construct validity through unidimensionality. Internal reliability was high (α = .86-.93, split-half = .90-.94)). The scale was predictive of future suicidal behaviors and suicidality (r = .68, .73, respectively), showed convergent validity, and the SABCS-4 demonstrated clinically relevant sensitivity to change. IRT analyses revealed the SABCS captured more information than the comparison measure, and better defined participants at low, moderate, and high risk. The SABCS is the first suicide risk measure to demonstrate no differential item functioning by sex, age, or ethnicity. In all comparisons, the SABCS showed incremental improvements over a highly endorsed scale through stronger predictive ability, reliability, and other properties. The SABCS is in the public domain, with this publication, and is suitable for clinical evaluations, public screening, and research. 相似文献
3.
4.
5.
Janne Alahuhta Sarian Kosten Munemitsu Akasaka Dominique Auderset Mattia M. Azzella Rossano Bolpagni Claudia P. Bove Patricia A. Chambers Eglantine Chappuis John Clayton Mary de Winton Frauke Ecke Esperança Gacia Gana Gecheva Patrick Grillas Jennifer Hauxwell Seppo Hellsten Jan Hjort Mark V. Hoyer Christiane Ilg Agnieszka Kolada Minna Kuoppala Torben Lauridsen En Hua Li Balázs A. Lukács Marit Mjelde Alison Mikulyuk Roger P. Mormul Jun Nishihiro Beat Oertli Laila Rhazi Mouhssine Rhazi Laura Sass Christine Schranz Martin Søndergaard Takashi Yamanouchi Qing Yu Haijun Wang Nigel Willby Xiao Ke Zhang Jani Heino 《Journal of Biogeography》2017,44(8):1758-1769
6.
7.
Justyna McIntyre Mary P. McLenigan Ekaterina G. Frank Xiaoxia Dai Wei Yang Yinsheng Wang Roger Woodgate 《The Journal of biological chemistry》2015,290(45):27332-27344
Human DNA polymerases (pols) η and ι are Y-family DNA polymerase paralogs that facilitate translesion synthesis past damaged DNA. Both polη and polι can be monoubiquitinated in vivo. Polη has been shown to be ubiquitinated at one primary site. When this site is unavailable, three nearby lysines may become ubiquitinated. In contrast, mass spectrometry analysis of monoubiquitinated polι revealed that it is ubiquitinated at over 27 unique sites. Many of these sites are localized in different functional domains of the protein, including the catalytic polymerase domain, the proliferating cell nuclear antigen-interacting region, the Rev1-interacting region, and its ubiquitin binding motifs UBM1 and UBM2. Polι monoubiquitination remains unchanged after cells are exposed to DNA-damaging agents such as UV light (generating UV photoproducts), ethyl methanesulfonate (generating alkylation damage), mitomycin C (generating interstrand cross-links), or potassium bromate (generating direct oxidative DNA damage). However, when exposed to naphthoquinones, such as menadione and plumbagin, which cause indirect oxidative damage through mitochondrial dysfunction, polι becomes transiently polyubiquitinated via Lys11- and Lys48-linked chains of ubiquitin and subsequently targeted for degradation. Polyubiquitination does not occur as a direct result of the perturbation of the redox cycle as no polyubiquitination was observed after treatment with rotenone or antimycin A, which both inhibit mitochondrial electron transport. Interestingly, polyubiquitination was observed after the inhibition of the lysine acetyltransferase KATB3/p300. We hypothesize that the formation of polyubiquitination chains attached to polι occurs via the interplay between lysine acetylation and ubiquitination of ubiquitin itself at Lys11 and Lys48 rather than oxidative damage per se. 相似文献
8.
9.
Activation of the cyclic AMP cascade as an oncogenic mechanism: the thyroid example. 总被引:2,自引:0,他引:2
Three cascades activate thyroid cell proliferation: the EGF-protein tyrosine kinase pathway, the phorbol ester-protein kinase C pathway and the thyrotropin-cyclic AMP pathway. While the first 2 cascades converge early, they remain distinct from the cyclic AMP cascade until very late in G1. The cyclic AMP cascade is characterized by an early and transient expression of c-myc, which may explain why it induces proliferation and differentiation expression. Constitutive activation of this cascade causes growth and hyperfunction, ie, hyperfunctioning adenomas. The various possible defects that could lead to such a constitutive activation are discussed. 相似文献
10.