全文获取类型
收费全文 | 636篇 |
免费 | 33篇 |
出版年
2023年 | 5篇 |
2022年 | 18篇 |
2021年 | 24篇 |
2020年 | 15篇 |
2019年 | 16篇 |
2018年 | 24篇 |
2017年 | 24篇 |
2016年 | 34篇 |
2015年 | 40篇 |
2014年 | 49篇 |
2013年 | 54篇 |
2012年 | 74篇 |
2011年 | 67篇 |
2010年 | 27篇 |
2009年 | 28篇 |
2008年 | 33篇 |
2007年 | 26篇 |
2006年 | 35篇 |
2005年 | 16篇 |
2004年 | 18篇 |
2003年 | 17篇 |
2002年 | 12篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1978年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有669条查询结果,搜索用时 15 毫秒
111.
Justyna Olszewska Eugenia Tęgowska 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2011,197(10):1021-1026
Transient receptor potential channels are implicated in thermosensation both in mammals and insects. The aim of our study
was to assess the effect of mammalian vanilloid receptor subtype 1 (TRPV1) agonist (capsaicin) and antagonist (capsazepine)
on insect behavioral thermoregulation. We tested behavioral thermoregulation of mealworms larvae intoxicated with capsaicin
and capsazepine in two concentrations (10−7 and 10−4 M) in a thermal gradient system for 3 days. Our results revealed that in low concentration, capsaicin induces seeking lower
temperatures than the ones selected by the insects that were not intoxicated. After application of capsazepine in the same
concentration, the mealworms prefer higher temperatures than the control group. The observed opposite effect of TRPV1 agonist
and antagonist on insect behavioral thermoregulation, which is similar to the effect of these substances on thermoregulation
in mammals, indicates indirectly that capsaicin may act on receptors in insects that are functionally similar to TRPV1. 相似文献
112.
113.
Justyna Lema-Rumińska 《Plant Cell, Tissue and Organ Culture》2011,106(3):531-535
Flow cytometry was used for analyzing DNA contents of nuclei isolated from in vitro grown somatic embryos, shoots and calli,
as well as mammillae of in vivo grown shoots of cactus, Copiapoa tenuissima Ritt. forma
monstruosa. Endoreduplication was detected in both in vitro grown somatic embryos, shoots and calli and in mammillae derived from in
vivo grown shoots. However, the lowest ploidy levels ranged from 2C to 4C in somatic embryos, and reaching up to 32C for in vitro grown shoots
and calli from mammillae. Whereas, ploidy levels of in vivo-derived mammillae ranged from 2C to 16C. The presence of 2,4-dichlorophenoxyacetic
acid (2,4-D) in the culture medium had no influence on levels of ploidy of regenerated tissues. The mean genome size of cactus
was calculated as 2C = 2.87 ± 0.05 picogram (pg). 相似文献
114.
Staniszewska M Słuczanowska-Głąbowska S Drukała J 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》2011,49(3):375-380
Stem cells represent a great hope for regenerative medicine. In adult life, stem cell deposits are kept in organ niches; the need for tissue or organ regeneration mobilizes stem cells via the SDF-1-CXCR4 regulation axis. Constant regeneration of the skin is achieved due to stem cell differentiation within the epidermis and the hair follicle; thus, skin may serve as an excellent source of stem cells. This is of paramount importance in the treatment of chronic skin wounds and burns. 相似文献
115.
Niderla-Bielińska J Moskalewski S 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》2011,49(2):335-343
The hair follicle consists of several distinctive epidermal cell layers. The hair root, which undergoes keratinization, is surrounded by two sheaths: the inner root sheath (IRS) and the outer root sheath (ORS). The ORS is continuous with the basal layer of the epidermis. Its cells do not keratinize in situ, unlike IRS. We have previously demonstrated that keratinization of the ORS was prevented by contact with the IRS in hair follicle mid-segments (i.e. fragments dissected from skin at the level above the hair bulb and below the opening of the sebaceous gland duct) cultured on agarose layer. The purpose of this study was to determine whether the same applies to the hair bulb. After isolation, intact bulbs or hair bulb-derived cells were incubated in suspension in a low or high calcium medium. The level of mRNA for differentiation markers: involucrin, filaggrin, keratinocyte differentiation associated protein and trichohyalin, was studied by RealTime PCR. We observed increased Ca(2+) upregulated expression of involucrin, filaggrin, trichohyalin and Kdap in cultures of bulb-derived cells, but in hair bulbs downregulation of involucrin and trichohyalin was observed. We concluded that the inner root sheath exerts an inhibitory effect on the expression of involucrin and trichohyalin already in the hair bulbs. The observation that downregulation of involucrin expression under Ca(2+) influence occurs both in hair bulb and midsegments could simplify future experiments, since their separation does not seem to be necessary. 相似文献
116.
117.
Swiatek-Kozlowska J Brasuń J Dobosz A Sochacka E Glowacka A 《Journal of inorganic biochemistry》2003,93(3-4):119-124
Potentiometric and spectroscopic data obtained for the complexes of two thio-substituted uridine-monophosphates with Cu(2+), Ni(2+) and Cd(2+) ions have shown that both thionucleotide are more effective ligands than their nucleoside analogues. The basic binding site for all metal ions is the sulfur atom. The chelation by adjacent N(3) donor is also likely, although unfavorable four-membered chelate ring is formed. 相似文献
118.
Micha? Mi?tus El?bieta Nowak Marcin Jaciuk Pawe? Kustosz Justyna Studnicka Marcin Nowotny 《Nucleic acids research》2014,42(16):10762-10775
Rad2/XPG belongs to the flap nuclease family and is responsible for a key step of the eukaryotic nucleotide excision DNA repair (NER) pathway. To elucidate the mechanism of DNA binding by Rad2/XPG, we solved crystal structures of the catalytic core of Rad2 in complex with a substrate. Rad2 utilizes three structural modules for recognition of the double-stranded portion of DNA substrate, particularly a Rad2-specific α-helix for binding the cleaved strand. The protein does not specifically recognize the single-stranded portion of the nucleic acid. Our data suggest that in contrast to related enzymes (FEN1 and EXO1), the Rad2 active site may be more accessible, which would create an exit route for substrates without a free 5′ end. 相似文献
119.
120.
Aleksandra Zuber Julia Borowczyk Eliza Zimolag Malgorzata Krok Zbigniew Madeja Elzbieta Pamula Justyna Drukala 《Cellular & molecular biology letters》2014,19(2):297-314
Degradable aliphatic polyesters such as polylactides, polyglycolides and their copolymers are used in several biomedical and pharmaceutical applications. We analyzed the influence of poly(L-lactide-co-glycolide) (PLGA) thin films on the adhesion, proliferation, motility and differentiation of primary human skin keratinocytes and fibroblasts in the context of their potential use as cell carriers for skin tissue engineering. We did not observe visible differences in the morphology, focal contact appearance, or actin cytoskeleton organization of skin cells cultured on PLGA films compared to those cultured under control conditions. Moreover, we did not detect biologically significant differences in proliferative activity, migration parameters, level of differentiation, or expression of vinculin when the cells were cultured on PLGA films and tissue culture polystyrene. Our results indicate that PLGA films do not affect the basic functions of primary human skin keratinocytes and fibroblasts and thus show acceptable biocompatibility in vitro, paving the way for their use as biomaterials for skin tissue engineering. 相似文献