全文获取类型
收费全文 | 4281篇 |
免费 | 257篇 |
国内免费 | 1篇 |
出版年
2022年 | 23篇 |
2021年 | 42篇 |
2020年 | 17篇 |
2019年 | 36篇 |
2018年 | 51篇 |
2017年 | 48篇 |
2016年 | 80篇 |
2015年 | 128篇 |
2014年 | 136篇 |
2013年 | 263篇 |
2012年 | 285篇 |
2011年 | 282篇 |
2010年 | 173篇 |
2009年 | 172篇 |
2008年 | 245篇 |
2007年 | 259篇 |
2006年 | 271篇 |
2005年 | 248篇 |
2004年 | 246篇 |
2003年 | 228篇 |
2002年 | 237篇 |
2001年 | 90篇 |
2000年 | 71篇 |
1999年 | 84篇 |
1998年 | 59篇 |
1997年 | 53篇 |
1996年 | 55篇 |
1995年 | 53篇 |
1994年 | 37篇 |
1993年 | 42篇 |
1992年 | 49篇 |
1991年 | 35篇 |
1990年 | 38篇 |
1989年 | 48篇 |
1988年 | 34篇 |
1987年 | 25篇 |
1986年 | 29篇 |
1985年 | 15篇 |
1984年 | 24篇 |
1983年 | 16篇 |
1982年 | 17篇 |
1981年 | 36篇 |
1980年 | 19篇 |
1979年 | 13篇 |
1977年 | 14篇 |
1975年 | 15篇 |
1974年 | 9篇 |
1973年 | 11篇 |
1972年 | 11篇 |
1969年 | 9篇 |
排序方式: 共有4539条查询结果,搜索用时 15 毫秒
181.
Transitory perturbations in the level of cytosolic Ca2+ are well known to be involved in numerous cell signaling pathways in both plant and animal systems. However, not much is known at present about the molecular identity of plant plasma membrane Ca2+ conducting ion channels or their specific roles in signal transduction cascades. A recent study employing genetic approaches as well as patch clamp electrophysiological analysis of channel currents has provided the first such direct evidence linking a specific gene product with inward Ca2+ currents across the plant cell membrane. This work identified Ca2+ permeation through (Arabidopsis) cyclic nucleotide gated channel isoform 2 (CNGC2) as contributing to the plant innate immunity signaling cascade initiated upon perception of a pathogen. Here, we expand on the implications of CNGC2 mediated cytosolic Ca2+ elevations associated with plant cell response to pathogen recognition, and propose some additional steps that may be involved in the innate immunity signal cascade.Key Words: calcium, CNGC, hypersensitive response, nitric oxide, plant innate immunity, plant ion channel, reactive oxygen species 相似文献
182.
Marko-Varga G Ogiwara A Nishimura T Kawamura T Fujii K Kawakami T Kyono Y Tu HK Anyoji H Kanazawa M Akimoto S Hirano T Tsuboi M Nishio K Hada S Jiang H Fukuoka M Nakata K Nishiwaki Y Kunito H Peers IS Harbron CG South MC Higenbottam T Nyberg F Kudoh S Kato H 《Journal of proteome research》2007,6(8):2925-2935
Personalized medicine allows the selection of treatments best suited to an individual patient and disease phenotype. To implement personalized medicine, effective tests predictive of response to treatment or susceptibility to adverse events are needed, and to develop a personalized medicine test, both high quality samples and reliable data are required. We review key features of state-of-the-art proteomic profiling and introduce further analytic developments to build a proteomic toolkit for use in personalized medicine approaches. The combination of novel analytical approaches in proteomic data generation, alignment and comparison permit translation of identified biomarkers into practical assays. We further propose an expanded statistical analysis to understand the sources of variability between individuals in terms of both protein expression and clinical variables and utilize this understanding in a predictive test. 相似文献
183.
Enoki N Kiyoshima T Sakai T Kobayashi I Takahashi K Terada Y Sakai H 《Journal of molecular histology》2007,38(4):321-332
This study investigated the age-dependent changes in the number of BrdU- and TUNEL-positive cells in murine gingival tissue
and submandibular gland, and compared the findings with those in other tissues and organs. The cell proliferative activity
was decreased after 20 weeks of age in epithelial cells of the gingiva, tongue, buccal mucosa and skin. A decreased cell proliferative
activity was also associated with aging in the liver and kidney parenchymal cells. Meanwhile, cell death showed peculiar changes
in gingival subepithelial tissue, and mucous and serous acini of the submandibular gland. An increase of TUNEL-positive cells
was demonstrated in gingival subepithelial tissue after 20-week-old of age. A significant increase of TUNEL-positive cells
was also found in the mucous acinar cells in the 20-week-old mice and in the serous acini after 20 weeks. The fluctuation
in the number of TUNEL-positive cells in the subepithelial tissue of the skin, and BrdU- and TUNEL-positive staining ratios
in the liver was smaller than that in other tissue and organs throughout life. This study may provide useful information for
better understanding the influence of aging on the functional alteration that occurs in the gingival tissue and submandibular
gland of the elderly. 相似文献
184.
Kiyosaki T Matsumoto I Asakura T Funaki J Kuroda M Misaka T Arai S Abe K 《The FEBS journal》2007,274(8):1908-1917
We cloned a new cysteine proteinase of wheat seed origin, which hydrolyzed the storage protein gliadin almost specifically, and was named gliadain. Gliadain mRNA was expressed 1 day after the start of seed imbibition, and showed a gradual increase thereafter. Gliadain expression was suppressed when uniconazol, a gibberellin synthesis inhibitor, was added to germinating seeds. Histochemical detection with anti-gliadain serum indicated that gliadain was present in the aleurone layer and also that its expression intensity increased in sites nearer the embryo. The enzymological characteristics of gliadain were investigated using recombinant glutathione S-transferase (GST)-progliadain fusion protein produced in Escherichia coli. The GST-progliadain almost specifically digested gliadin into low molecular mass peptides. These results indicate that gliadain is produced via gibberellin-mediated gene activation in aleurone cells and secreted into the endosperm to digest its storage proteins. Enzymologically, the GST-progliadain hydrolyzed benzyloxycarbonyl-Phe-Arg-7-amino-4-methylcoumarin (Z-Phe-Arg-NH(2)-Mec) at K(m) = 9.5 microm, which is equivalent to the K(m) value for hydrolysis of this substrate by cathepsin L. Hydrolysis was inhibited by two wheat cystatins, WC1 and WC4, with IC(50) values of 1.7 x 10(-8) and 5.0 x 10(-8) m, respectively. These values are comparable with those found for GST-progliadain inhibition by E-64 and egg-white cystatin, and are consistent with the possibility that, in germinating wheat seeds, gliadain is under the control of intrinsic cystatins. 相似文献
185.
Kawakami Keisuke Tokutsu Ryutaro Kim Eunchul Minagawa Jun 《Photosynthesis research》2019,141(2):195-207
Photosynthesis Research - Crassulacean acid metabolism (CAM) is a specialized photosynthetic pathway present in a variety of genera including many epiphytic orchids. CAM is under circadian control... 相似文献
186.
Hiroko Kawakami Chihiro Suzuki Haruka Yamaguchi Kojiro Hara Masashi Komine Yoshikazu Yamamoto 《Bioscience, biotechnology, and biochemistry》2019,83(6):996-999
Endolichenic fungi, nonobligate microfungi that live in lichen, are promising as new bioresources of pharmacological compounds. We found that norlichexanthone isolated from the endolichenic fungus in Pertusaria laeviganda exhibited high antioxidant activity. Norlichexanthone produced by endolichenic fungus had the antioxidant activity with same level of ascorbic acid. This is the first report of high antioxidant activity of norlichexanthone.
Abbreviations: AAPH: 2,2?-azobis (2-methylpropionamidine) dihydrochloride; DPPH: 2,2-diphenyl-1-picrylhydrazyl; FL: fluorescein sodium salt; HPLC-PDA: high-performance liquid chromatography with photodiode array; LC-ESI-MS: liquid chromatography with electrospray ionization mass spectrometry; ORAC: oxygen radical absorbance capacity; PB: phosphate buffer; ROS: reactive oxygen species; TLC: thin-layer chromatography 相似文献
187.
188.
189.
Adrienne H K Roeder Marisa S Otegui Ram Dixit Charles T Anderson Christine Faulkner Yan Zhang Maria J Harrison Charlotte Kirchhelle Gohta Goshima Jeremy E Coate Jeff J Doyle Olivier Hamant Keiko Sugimoto Liam Dolan Heather Meyer David W Ehrhardt Arezki Boudaoud Carlos Messina 《The Plant cell》2022,34(1):72
As scientists, we are at least as excited about the open questions—the things we do not know—as the discoveries. Here, we asked 15 experts to describe the most compelling open questions in plant cell biology. These are their questions: How are organelle identity, domains, and boundaries maintained under the continuous flux of vesicle trafficking and membrane remodeling? Is the plant cortical microtubule cytoskeleton a mechanosensory apparatus? How are the cellular pathways of cell wall synthesis, assembly, modification, and integrity sensing linked in plants? Why do plasmodesmata open and close? Is there retrograde signaling from vacuoles to the nucleus? How do root cells accommodate fungal endosymbionts? What is the role of cell edges in plant morphogenesis? How is the cell division site determined? What are the emergent effects of polyploidy on the biology of the cell, and how are any such “rules” conditioned by cell type? Can mechanical forces trigger new cell fates in plants? How does a single differentiated somatic cell reprogram and gain pluripotency? How does polarity develop de-novo in isolated plant cells? What is the spectrum of cellular functions for membraneless organelles and intrinsically disordered proteins? How do plants deal with internal noise? How does order emerge in cells and propagate to organs and organisms from complex dynamical processes? We hope you find the discussions of these questions thought provoking and inspiring.We asked 15 experts to address what they consider to be the most compelling open questions in plant cell biology and these are their questions. 相似文献
190.
Shimamoto T Shimamoto T Xu XJ Okazaki N Kawakami H Tsuchiya T 《Journal of biochemistry》2001,129(4):607-613
Wild-type Citrobacter freundii cannot grow on melibiose as a sole source of carbon. The melibiose transporter gene melB was cloned from a C. freundii mutant M4 that could utilize melibiose as a sole carbon source. Although the cloned melB gene is closely similar to the melB genes of other bacteria, it is cryptic because of a frameshift mutation. Site-directed mutagenesis was used to construct a functional melB gene by deleting one nucleotide, resulting in the production of an active melibiose transporter. The active MelB transporter could utilize Na(+) and H(+) as coupling cations to melibiose transport. The amino acid sequence of the C. freundii MelB was found to be most similar to those of Salmonella typhimurium and Escherichia coli MelB. These facts are consistent with the phylogenetic relationship of bacteria and the cation coupling properties of the melibiose transporters. 相似文献