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61.
Hacer Esen Saadet Alpdağtaş Mehmet Mervan Çakar 《Preparative biochemistry & biotechnology》2019,49(5):529-534
AbstractSeveral protein expression systems can be used to get enzymes in required quantities and study their functions. Incorporating a polyhistidine tag is a beneficial way of getting various enzymes such as FDHs for industrial applications. The NAD+ dependent formate dehydrogenase from Chaetomium thermophilum (CtFDH) can be utilized for interconversion of formate to carbon dioxide coupled with the conversion of NAD+ to NADH. In this study, N-terminal His tagged CtFDH (N-CtFDH) and C-terminal His tagged CtFDH (C-CtFDH) was constructed to learn the effect of His tag location on the activity and kinetic parameters of the enzyme. The solubility of proteins was not affected by tag position, however, an interference on the N-terminal region caused a deterioration in specific activity and the kinetic ability of enzyme. The obtained results indicated that the C-terminus of the enzyme is an appropriate region for tag engineering. The C-CtFDH has an approximately three-fold larger specific activity and two-fold higher catalytic efficiency than N-CtFDH. The results suggest that insertion of a His-tag at the N-terminal or C-terminal end of CtFDH has different effects on the protein and the N-terminal fragment of the protein is crucial for the function of CtFDH. 相似文献
62.
Streptomyces caelestis DSM 40084 produces two osmolytes, viz. 2-O-(alpha-D-glucopyranosyl)-zeta-glyceric acid (GG) and trehalose. Both compounds were isolated and identified by nuclear magnetic resonance spectroscopy and mass spectrometry. A very sensitive regulation of the cell osmolytes was demonstrated in exponentially growing cultures. The intracellular levels of GG and trehalose increased 2x in response to a step change of medium osmolarity caused by 0.3% NaCl. 1H NMR analysis of the cell extracts did not confirm the presence of additional osmolytes. GG is a S. caelestis metabolite commonly released from the cells; its concentration reached 3 g/L during the cultivation in a yeast extract--(NH4)2SO4-glycerol medium. This is the first report on the occurrence of the ionic osmolyte GG in the genus Streptomyces and on its free excretion to the medium. 相似文献
63.
Biology Bulletin - In the trout production establishments all over the world, the most common pathogenic bacterial factors are increasing. Therefore, in this study, rainbow trout (Oncorhynchus... 相似文献
64.
Litvín Radek Bína David Herbstová Miroslava Pazderník Marek Kotabová Eva Gardian Zdenko Trtílek Martin Prášil Ondřej Vácha František 《Photosynthesis research》2019,142(2):137-151
Photosynthesis Research - Survival of phototrophic organisms depends on their ability to collect and convert enough light energy to support their metabolism. Phototrophs can extend their absorption... 相似文献
65.
The effect of orally or intraperitoneally administered particulate 1,3-β-d-glucan (PBG), carboxymethylglucan (CMG) or sulfoethylglucan (SEG), obtained from the culture filtrate ofSaccharomyces cerevisiae, on the functions of murine peritoneal adherent cells (PC) (peroxidase activity, nitric oxide synthesis), on relative organ
mass and on proliferation of splenocytes was determined. The modulating activities after parenteral and non-parenteral administration
of these polysaccharides were compared. Significant enhancement of NO production was observed only afterin vitro cultivation of PC in the presence of lipopolysaccharide (LPS) in groups of mice treated repeatedly orally with CMG, PBG and
SEG at a dose of 50 mg/kg body mass. Peroxidase activity increased significantly after repeated oral administration of CMG
and PBG at doses 150 and 50 mg/kg, SEG 150 mg/kg body mass. The peroxidase activity and NO synthesis in mice given a single
intraperitoneal injection of glucans (15 mg/kg body mass) were slightly higher than those after oral administration. Neither
a significant enhancement of relative organ mass nor enhancement of the proliferative response of splenocytes toin vitro added stimuli (LPS, phytohemagglutinin) after repeated oral or single intraperitoneal administration of β-glucans was observed. 相似文献
66.
Palanduz S Sever MS Oztürk S Taşçioğlu C Karan MA Sönmez G Cefle K Güler K 《Cell biology and toxicology》1999,15(1):13-17
We analyzed the induction of sister chromatid exchange (SCE) by cyclosporin A (CsA) as a marker of genotoxic potential. In 30 patients undergoing renal transplantation, SCE induction was tested before the introduction of CsA and 3 months later. We found that SCE frequency increased significantly at the end of 3 months. To our knowledge, this is the first study demonstrating in vivo induction of SCE by CsA in humans. We conclude that CsA has a genotoxic potential on human lymphocytes. 相似文献
67.
Extracellular oxidative enzyme production and PAH removal in soil by exploratory mycelium of white rot fungi 总被引:15,自引:0,他引:15
Čeněk Novotný Pavla Erbanová Václav Šašek Alena Kubátová Tomáš Cajthaml Elke Lang Jürgen Krahl František Zadražil 《Biodegradation》1999,10(3):159-168
Selected strains of three species of white rot fungi, Pleurotus ostreatus, Phanerochaete chrysosporium and Trametes versicolor,
were grown in sterilized soil from straw inocula. The respective colonization rates and mycelium density values decreased
in the above mentioned order. Three- and four-ringed PAHs at 50 ppm inhibited growth of fungi in soil to some extent. The
activities of fungal MnP and laccase (units per g dry weight of straw or soil), extracted with 50 mM succinate-lactate buffer
(pH 4.5), were 5 to 20-fold higher in straw compared to soil. The enzyme activities per g dry soil in P. ostreatus and T.
versicolor were similar, in contrast to P. chrysosporium, where they were extremely low. Compared to the aerated controls,
P. ostreatus strains reduced the levels of anthracene, pyrene and phenanthrene by 81–87%, 84–93% and 41–64% within 2 months,
respectively. During degradation of anthracene, all P. ostreatus strains accumulated anthraquinone. PAH removal rates in P.
chrysosporium and T. versicolor soil cultures were much lower. 相似文献
68.
Chlorophyll a fluorescence induction measured by a fluorometer with a high temperature stressed plant material shows a new K step which
is a clear peak due to fast fluorescence rise and subsequent decrease of fluorescence intensity. We focused on an explanation
of the decrease of fluorescence after the K step using artificial electron acceptors and donors to photosystem 2 (PS2). Addition
of the artificial electron acceptors or donors suppressed the decrease of fluorescence after the K step. We suggest that the
decrease mainly reflects (by more than 81 %) an energy loss process in the reaction centre of PS2 which is most probably a
nonradiative charge recombination between P680+ (oxidised primary electron donor in PS2) and a negative charge stored on either Pheo− or QA
− (reduced primary electron acceptor of PS2 and reduced primary quinone electron acceptor of PS2, respectively). We suggest
that the energy loss process is only possible when the inhibition of both the donor and the acceptor sides of PS2 occurs.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
69.
Li J Jain M Vunsh R Vishnevetsky J Hanania U Flaishman M Perl A Edelman M 《Plant cell reports》2004,22(7):457-464
The development of tissue culture systems in duckweeds has, to date, been limited to species of the genus Lemna. We report here the establishment of an efficient tissue culture cycle (callus induction, callus growth and plant regeneration) for Spirodela oligorrhiza Hegelm SP, Spirodela punctata 8717 and Lemna gibba var. Hurfeish. Significant differences were found among the three duckweed species pertaining to carbohydrate and phytohormone requirements for callus induction, callus growth and frond regeneration. In vitro incubation with poorly assimilated carbohydrates such as galactose (S. oligorrhiza SP and L. gibba var. Hurfeish) and sorbitol (S. punctata 8717) as sole carbon source yielded high levels of callus induction on phytohormone-supplemented medium. Sorbitol is required for optimal callus growth of S. oligorrhiza SP and S. punctata 8717, while sucrose is required for callus growth of L. gibba var. Hurfeish. Sucrose either alone (S. oligorrhiza SP, L. gibba var. Hurfeish) or in addition to sorbitol (S. punctata 8717) is required for frond regeneration.Abbreviations
ABA:
(±)-Abscisic acid
-
BA:
N6-Benzyladenine
-
2,4-D
2,4-Dichlorophenoxyacetic acid
-
Dicamba:
3,6-Dichloro-2-methoxybenzoic acid
-
2iP:
N6-(2-Isopentenyl)adenine
-
NAA:
-Naphthaleneacetic acid
-
PCA:
p-Chlorophenoxy acetic acid
-
Picloram:
4-Amino-3,5,6-trichloropicolinic acid
-
TDZ:
Thidiazuron
Communicated by A. AltmanJ. Li and M. Jain contributed equally to the research reported in this article. 相似文献
70.
Etelka?Farkas Yiffat?Katz Sudhakar?Bhusare Reuven?Reich Gerd-Volker?R?schenthaler Martin?K?nigsmann Eli?BreuerEmail author 《Journal of biological inorganic chemistry》2004,9(3):307-315
Overactive matrix metalloproteinases (MMPs) are associated with a variety of disease states. Therefore, their inhibition is a highly desirable goal. Yet, more than a decade of worldwide activity has not produced even one clinically useful inhibitor. Because of the crucial role of zinc in the activity of the enzyme, the design of inhibitors is usually based upon a so-called zinc binding group (ZBG). Yet, many of the hitherto synthesized potent inhibitors failed clinically, presumably because they bind stronger to metals other than zinc. We have developed in vivo potent inhibitors based on the carbamoylphosphonic group as a putative ZBG. In this paper we report stability constants for Ca(II), Mg(II), Zn(II) and Cu(II) complexes of two potent, in vivo active, MMP inhibitors, cyclopentylcarbamoylphosphonic acid (1) and 2-(N,N-dimethylamino)ethylcarbamoylphosphonic acid (2). Precipitation prevented the determination of stability constants for iron(III) complexes of 1 and 2. For comparison with carbamoylphosphonates 1 and 2, we synthesized 2-cyclohexyl-1,1-difluoroethylphosphonic acid (3), which does not inhibit MMP, and determined the stability constants of its complexes with Mg(II), Ca(II) and Zn(II). Comparison with the values obtained from the complexes of 1 and 2 with those from 3 indicates participation of the C=O group in the metal binding of the former compounds. The complex stability orders for both 1 and 2 are Ca(II)<Mg(II)<Zn(II)<Cu(II). In addition, the results indicate that at pH>8 the dimethylamino group of compound 2 can also participate in the binding of the transition metals Cu and Zn. On the other hand, the amino group in carbamoylphosphonic acid 2 lowers the stability of the complexes with metals favoring oxygen ligands (Ca, Mg and Fe) and increases the selectivity towards Zn. These results are helpful for rationalizing the results observed on our MMP inhibitors hitherto examined, and are expected to be useful for the design of new selective inhibitors.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00775-004-0524-5 相似文献