全文获取类型
收费全文 | 6915篇 |
免费 | 338篇 |
国内免费 | 5篇 |
专业分类
7258篇 |
出版年
2023年 | 13篇 |
2022年 | 50篇 |
2021年 | 70篇 |
2020年 | 56篇 |
2019年 | 53篇 |
2018年 | 81篇 |
2017年 | 68篇 |
2016年 | 158篇 |
2015年 | 229篇 |
2014年 | 236篇 |
2013年 | 505篇 |
2012年 | 449篇 |
2011年 | 485篇 |
2010年 | 293篇 |
2009年 | 273篇 |
2008年 | 467篇 |
2007年 | 498篇 |
2006年 | 451篇 |
2005年 | 440篇 |
2004年 | 505篇 |
2003年 | 383篇 |
2002年 | 398篇 |
2001年 | 65篇 |
2000年 | 55篇 |
1999年 | 65篇 |
1998年 | 96篇 |
1997年 | 72篇 |
1996年 | 69篇 |
1995年 | 69篇 |
1994年 | 59篇 |
1993年 | 51篇 |
1992年 | 41篇 |
1991年 | 48篇 |
1990年 | 38篇 |
1989年 | 36篇 |
1988年 | 40篇 |
1987年 | 26篇 |
1986年 | 24篇 |
1985年 | 20篇 |
1984年 | 23篇 |
1983年 | 17篇 |
1982年 | 20篇 |
1981年 | 24篇 |
1980年 | 29篇 |
1979年 | 13篇 |
1978年 | 11篇 |
1977年 | 19篇 |
1976年 | 11篇 |
1975年 | 9篇 |
1973年 | 10篇 |
排序方式: 共有7258条查询结果,搜索用时 0 毫秒
21.
Takeshi Kikuchi 《Journal of Protein Chemistry》1996,15(6):539-545
In a previous paper we demonstrated that the short-range compact regions in atrial natriuretic factor (-hANF) predicted by the average distance map (ADM) correspond to its active sites [Kikuchi,J. Protein Chem.11, 579–581 (1992)]. In the present paper we apply the same method to other bioactive peptides and peptidic enzyme inhibitors. We again observe that active sites in each peptide are contained in short-range compact regions predicted by the ADM for the peptide. This demonstrates that the ADM method predicts the possible location of active sites in biologically active peptides in general. The possibility of practical application of the present method to rational drug design is also discussed. 相似文献
22.
Satoshi Iuchi Kazuko Yamaguchi-Shinozaki Takeshi Urao Kazuo Shinozaki 《Journal of plant research》1996,109(4):415-424
Ten cDNAs for drought-inducible genes were isolated using differential screening of a cDNA library prepared from 10-hr dehydrated
cowpea plants,Vigna unguiculata (S. Iuchi, K. Yamaguchi-Shinozaki, T. Urao, T. Terao, K. Shinozaki; Plant Cell Physiology, 1996 in press). Two of the cDNA
clones, designated CPRD12 and CPRD46, were sequenced and characterized. The CPRD12 and CPRD46 cDNAs encode putative proteins
related to nonmetallo-short-chain alcohol dehydrogenase (CPRD12) and chloroplastic lipoxygenase (CPRD46). Northern blot analysis
revealed that these genes are induced by high-salinity stress and exogenous abscisic acid, but not by cold stress. The CPRD46
gene is also responsive to heat stress and methyl jasmonate and salicylic acid. Genomic Southern blot analysis suggested that
CPRD12 constitutes a small gene family, but that CPRD46 is a single copy gene. We discuss the possible functions of these
two CPRD gene products under drought stress. 相似文献
23.
24.
By means of an in vivo brain microdialysis, the effect of different concentrations of physostigmine on the acetylcholine level in the dialysate of rat frontal cortex was studied. Perfusion of the various degrees of physostigmine (eserine) concentration (10 nM−10 μM) into the cortex through the dialysis membrane increased the basal acetylcholine level in a dose-dependent manner. In the presence of 10 nM, 0.1 μM and 10 μM physostigmine in the perfusate, systemic treatment with scopolamine (0.5 mg/kg, i.p.) increased 200, 270 and 510%, respectively, the relative acetylcholine level in the dialysates in comparison with the corresponding basal levels, while in the absence of physostigmine the treatment increased it only 40%. From these results, it appears that perfusion of physostigmine at a variety of concentrations, changes not only the basal level of acetylcholine induced by the inhibition of acetylcholinesterase but also the relative acetylcholine output induced by systemic treatment with scopolamine. 相似文献
25.
Takeshi Tabira Jun-ichi Inobe Keiichi Nakahara Mitsuhiro Osame Takashi Yamamura 《Neurochemical research》1994,19(8):1067-1071
To understand the immune mechanism suggested in HTLV-I-associated myelopathy (HAM/TSP), we investigated T cell response to proteolipid protein (PLP). Because of high autologous proliferative response (APR) of peripheral blood mononuclear cells (PBMC) in culture, the lymphocyte proliferation assay was not useful in this disease. Unexpectedly, however, APR was profoundly (70–98%) suppressed in 6 of 9 cases when PLP peptide 105-124 was added in the culture. PLP peptide 85-104 or 145-159 also suppressed APR in a few cases. Time course study showed that the peptide-mediated suppression became apparent after day 4 in culture. The results can be interpreted as that suppressor cells recognizing the PLP peptides were present in the PBMC of HAM/TSP patients and suppressed the APR as the consequence of antigen specific response. This may indicate that a T cell response to certain PLP determinants is involved in the pathomechanism of HAM/TSP at least in part. Molecular mimicry between PLP and HTLV-I mayaccount for the T cell sensitization to PLP in HAM/TSP.Special issue dedicated to Dr. Marjorie B. Lees. 相似文献
26.
Hideaki Sato Hideki Hirayama Takeshi Yamamoto Yoshimasa Lchio Fumiaki Ishizawa Michinao Mizugaki 《Luminescence》1994,9(2):73-77
The purpose of the study was to evaluate the quality of Toki-shakuyaku-san extract granules (TJ-23) using chemiluminescence (CL). A linear relationship was obtained between the log value of the CL of TJ-23 and the reaction temperature. An excellent correlation (r= 0.999) was found between the slope of this curve (ΔA) and the colour intensity due to the browning reaction occurring at the early stage of the Maillard reaction. 相似文献
27.
Takeshi Kikuchi 《Journal of Protein Chemistry》1993,12(5):515-523
It has been shown that probable portions which form contacts in a protein can be predicted by means of an average distance map (ADM) as well as regular structures (-helices and -turns) defined as short-range compact regions (Kikuchiet al., 1988a,c). In this paper, we analyze the occurrence of those portions and short-range compact regions on ADMs for various proteins regarding their folding types. We have found out that each folding type of proteins shows characteristic distribution of such parts on ADMS. We also discuss the possibility of the prediction of folding types of proteins by ADMs. 相似文献
28.
Leptocephalus eel larvae will feed in aquaria 总被引:1,自引:0,他引:1
Synopsis Premetamorphosing larvae of Muraenesox cinereus (Muraenesocidae) and Conger myriaster (Congridae), caught and kept alive in aquaria, repeatedly bit pieces out of a lump of squid paste. By coloring the paste with Brilliant Red, ingestion and defecation were clearly seen through the transparent gut. The paste is not their natural food, but nevertheless a possible food item for rearing eels from eggs; most previous efforts have failed inasmuch as the larvae have starved. 相似文献
29.
Shuhei Takatsuka Takeshi Kubota Yuta Kurashina Sho Kurihara Motoki Hirabayashi Masato Fujioka Hirotaka James Okano Hiroaki Onoe 《Biotechnology and bioengineering》2023,120(8):2371-2377
Adeno-associated virus (AAV)-based gene therapy holds promise as a fundamental treatment for genetic disorders. For clinical applications, it is necessary to control AAV release timing to avoid an immune response to AAV. Here we propose an ultrasound (US)-triggered on-demand AAV release system using alginate hydrogel microbeads (AHMs) with a release enhancer. By using a centrifuge-based microdroplet shooting device, the AHMs encapsulating AAV with tungsten microparticles (W-MPs) are fabricated. Since W-MPs work as release enhancers, the AHMs have high sensitivity to the US with localized variation in acoustic impedance for improving the release of AAV. Furthermore, AHMs were coated with poly-l -lysine (PLL) to adjust the release of AAV. By applying US to the AAV encapsulating AHMs with W-MPs, the AAV was released on demand, and gene transfection to cells by AAV was confirmed without loss of AAV activity. This proposed US-triggered AAV release system expands methodological possibilities in gene therapy. 相似文献
30.
Ota Yoko; Ario Takeshi; Hayashi Koji; Nakagawa Tsuyoshi; Hattori Tsukaho; Maeshima Masayoshi; Asahi Tadashi 《Plant & cell physiology》1992,33(3):225-232
Catalases purified from endosperm glyoxysomes and non-specializedmicrobodies from hypocotyls of castor bean seedlings differedin their specific activity [90164 and 0.894.9kunits (mg protein)1, respectively] and in their constituentsubunits [two subunits of 54 and 56 kDa for the endosperm enzymeand only one of 56 kDa for the hypocotyl enzyme]. Immunoblotanalysis also showed that particulate fractions from the endospermsand from etiolated and green cotyledons contained two catalasesubunits of 54 and 56 kDa, whereas such fractions from the hypocotylsand roots contained only the 56-kDa subunit. Leaf peroxisomesfrom green leaves had two catalase subunits of around 55 kDaeach. Results of translation in vitro indicated that the 54-and 56-kDa subunits were translated from distinct mRNAs andlevels of both mRNAs increased in the endosperms during germination,prior to increases in levels of catalase proteins. In the hypocotyls,the 56-kDa subunit seemed to be synthesized constitutively.
1Present addresses: YO, Toyota Central Institute, 31-9 Musashizuka,Nagabuchi, Nagakute, Aichi 480-11, Japan 相似文献