全文获取类型
收费全文 | 4390篇 |
免费 | 185篇 |
国内免费 | 3篇 |
出版年
2023年 | 6篇 |
2022年 | 29篇 |
2021年 | 46篇 |
2020年 | 25篇 |
2019年 | 48篇 |
2018年 | 75篇 |
2017年 | 43篇 |
2016年 | 81篇 |
2015年 | 122篇 |
2014年 | 164篇 |
2013年 | 305篇 |
2012年 | 303篇 |
2011年 | 274篇 |
2010年 | 185篇 |
2009年 | 185篇 |
2008年 | 296篇 |
2007年 | 278篇 |
2006年 | 293篇 |
2005年 | 278篇 |
2004年 | 305篇 |
2003年 | 275篇 |
2002年 | 259篇 |
2001年 | 33篇 |
2000年 | 37篇 |
1999年 | 33篇 |
1998年 | 63篇 |
1997年 | 50篇 |
1996年 | 39篇 |
1995年 | 38篇 |
1994年 | 33篇 |
1993年 | 31篇 |
1992年 | 32篇 |
1991年 | 33篇 |
1990年 | 27篇 |
1989年 | 35篇 |
1988年 | 25篇 |
1987年 | 13篇 |
1986年 | 19篇 |
1985年 | 16篇 |
1984年 | 20篇 |
1983年 | 21篇 |
1982年 | 18篇 |
1981年 | 12篇 |
1980年 | 14篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 13篇 |
1973年 | 6篇 |
排序方式: 共有4578条查询结果,搜索用时 15 毫秒
191.
192.
193.
Asadulghani Nitta K Kaneko Y Kojima K Fukuzawa H Kosaka H Nakamoto H 《Archives of microbiology》2004,182(6):487-497
194.
Nakajima Y Kobayashi K Yamagishi K Enomoto T Ohmiya Y 《Bioscience, biotechnology, and biochemistry》2004,68(3):565-570
A secreted luciferase from the marine ostracod, Vargula hilgendorfii, is a useful tool for gene expression assays in living mammalian cells. We have cloned the cDNA of a new secreted luciferase from the ostracod Cypridina noctiluca, which inhabits the coast of Japan. C. noctiluca luciferase consists of 553 amino acid residues with a molecular mass of 61,415 Da, as deduced from the nucleotide sequence. The homologies of nucleotide and amino acid sequences with V. hilgendorfii luciferase are 79.2% and 83.1%, respectively. C. noctiluca luciferase can expressed in and secreted from cultured mammalian cells. The characteristic properties of expressed C. noctiluca luciferase are similar to those of V. hilgendorfii luciferase. However, the activity of C. noctiluca luciferase in culture medium is much higher than that of V. hilgendorfii luciferase, suggesting that C. noctiluca luciferase is a highly potent reporter enzyme for real-time and continuous monitoring of gene expression in living cells. 相似文献
195.
Hattori S Kawaharada C Tazaki H Fujimori T Kimura K Ohnishi M Nabeta K 《Bioscience, biotechnology, and biochemistry》2004,68(12):2656-2659
Thermally decomposed products of (+/-)-linalyl beta-D-glucoside were analyzed by GC and GC/MS. 2,6-dimethyl-2,6-octadienes produced by mild pyrolysis of linalyl beta-D-glucopyranoside under a vacuum were detected and characterized by MS and NMR spectroscopy. This suggests that 2,6-dimethyl-2,6-octadienes are produced during thermal decomposition of the glucoside via proton transfer from the anomeric position to C-6 in the aglycon moiety. A stable isotope labeling experiment directly indicated the new reaction mechanism. 相似文献
196.
Yasuda S Wu PS Hattori E Tachibana H Yamada K 《Bioscience, biotechnology, and biochemistry》2004,68(1):51-58
A method for simultaneous detection and quantification is presented to determine the presence of isoflavones and bisphenol A in a biological sample. A coulometric array detector was used with reversed-phase high-performance liquid chromatography (HPLC). Daidzein (1), glycitein (2), genistein (3) and their glucoside conjugates, daidzin (4), glycitin (5) and genistin (6), were measured as phytochemicals. Also assayed here was equol (7), a metabolite from compound 1, and bisphenol A (8), an industrial chemical that acts as an endocrine disrupter. All chemicals were simultaneously detected by using a 600-mV single detection voltage with high efficacy. A mixture of 1, 3 and 8 was orally administered to rats, and the levels of these three chemicals in the serum were clearly increased after a 4 kU beta-glucuronidase treatment. The levels of compounds 1 and 3 in the serum were detected at 1665 and 2040 ng/ml, while 8 was at a low level of 417 ng/ml. Compound 7 in the serum was not detected until after enzymatic hydrolysis (72 ng/ml). These results suggest that this analytical method would be useful for metabolic and pharmacokinetic studies on isoflavones and bisphenol A. 相似文献
197.
Van Klink JW Baek SH Barlow AJ Ishii H Nakanishi K Berova N Perry NB Weavers RT 《Chirality》2004,16(8):549-558
Several Anisotome diterpene derivatives were synthesized in an attempt to obtain a crystalline compound for X-ray analysis. Although we were unable to obtain a suitable crystal, the absolute configuration of the irregular diterpene skeleton was determined using two other techniques: a circular dichroism (CD) protocol based on a tetraarylporphyrin molecular tweezer that allowed prediction of the absolute stereochemistry on a microscale level, and a method employing differences in NMR shifts from derivatization of the naturally occurring acid 1 with enantiomers of a phenylglycine methyl ester (PGME) chiral anisotropic reagent. The excellent agreement between the CD and NMR methods led to the assignment of a 2S-absolute configuration for anisotomenoic acid 1. 相似文献
198.
199.
Takahashi K Yamamoto H Yokote Y Hattori M 《Bioscience, biotechnology, and biochemistry》2004,68(9):1875-1881
Differential scanning calorimetry (DSC) was applied to elucidate the thermal behavior of fowl feather keratins (barbs, rachis, and calamus) with different morphological features. The DSC curves exhibited a clear and relatively large endothermic peak at about 110-160 degrees C in the wet condition. A considerable decrease in transition temperature with urea and its helical structure content estimated by Fourier transform infrared spectroscopy (FT-IR), and the disappearance of one of the diffraction peaks with heating at 160 degrees C for 30 min, indicated that DSC could be used to evaluate the thermal behavior of keratin. Barbs showed a lower denaturation temperature than rachis and calamus. The pulverized samples showed a slightly higher denaturation temperature than the native samples. In the dry condition, thermal transition occurred in a markedly higher temperature region close to 170-200 degrees C. It is hence concluded that fowl feather keratins have very high thermal stability, and that the elimination of water brings about even greater thermal stability. 相似文献
200.
Lim BO Yamada K Cho BG Jeon T Hwang SG Park T Kang SA Park DK 《Bioscience, biotechnology, and biochemistry》2004,68(11):2391-2394
We compared the immunomodulating activities in mice of extracts from Phellinus linteus grown on germinated brown rice (PB), Phellinus linteus (PL) alone, and germinated brown rice (BR) alone. The PL, BR and PB-treated mice were administered with the respective extract (2 mg/head/day) by oral gavage for 4 weeks. All extracts markedly decreased the IgE production and allergic responses in serum and splenocytes. PL and PB increased the proportion of CD4(+) but not CD8(+) T cells in splenocytes. Cytokine production was significantly augmented in all treated mice; the concentration of IFN-gamma was greater in the PL, BR and PB mice than in the control group. The concentration of IL-10 was lower in the BR group than in the other groups. These results may be related to the suppression of IgE production. We conclude that PB modulated the immune responses of IgE production and Th1/Th2 cytokine secretion in murine splenocytes. 相似文献