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排序方式: 共有886条查询结果,搜索用时 15 毫秒
881.
Bernal C. Vidal L. Valdivieso E. Coello N. 《World journal of microbiology & biotechnology》2003,19(3):255-261
A strain of Kocuria rosea able to secrete keratin-hydrolysing proteinases (keratinases) in submerged batch cultures with finely milled feathers as carbon and nitrogen sources was studied. The highest production of keratinases was obtained when feathers were used as the only fermentation substrate (17 U/mg). Considerably lower activity was present in cultures containing glucose and others nutrient supplements. The optimum temperature and pH for keratinolytic activity was 40 °C and 10, respectively. Gelatin-sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) electrophoresis analysis showed that Kocuria rosea grown on feathers secreted at least two alkaline extracellular proteases with apparent molecular weights of 90.2 and >200 kDa, respectively. These proteolytic activities appear sequentially during microbial growth. Keratinolytic activity was strongly inhibited by phenylmethanesulphonyl fluoride (PMSF), chymostatin and crystalline soybean trypsin inhibitor, indicating the presence of serine proteases. Proteolytic enzymes derived from the biodegradation of feathers by this microorganism could be a useful biotechnological tool in the leather, food and cosmetic industries. 相似文献
882.
Fatema Rahman Tra-Mi Nguyen Olayiwola A Adekoya Cristina Campestre Paolo Tortorella Ingebrigt Sylte Jan-Olof Winberg 《Journal of enzyme inhibition and medicinal chemistry》2021,36(1):819
Compounds containg catechol or bisphosphonate were tested as inhibitors of the zinc metalloproteases, thermolysin (TLN), pseudolysin (PLN) and aureolysin (ALN) which are bacterial virulence factors, and the human matrix metalloproteases MMP-9 and −14. Inhibition of virulence is a putative strategy in the development of antibacterial drugs, but the inhibitors should not interfere with human enzymes. Docking indicated that the inhibitors bound MMP-9 and MMP-14 with the phenyl, biphenyl, chlorophenyl, nitrophenyl or methoxyphenyl ringsystem in the S1′-subpocket, while these ringsystems entered the S2′- or S1 -subpockets or a region involving amino acids in the S1′- and S2′-subpockets of the bacterial enzymes. An arginine conserved among the bacterial enzymes seemed to hinder entrance deeply into the S1′-subpocket. Only the bisphosphonate containing compound RC2 bound stronger to PLN and TLN than to MMP-9 and MMP-14. Docking indicated that the reason was that the conserved arginine (R203 in TLN and R198 in PLN) interacts with phosphate groups of RC2. 相似文献
883.
S. Ya. Zhanaeva A. I. Dyakov T. A. Alekseenko T. A. Korolenko 《Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry》2009,3(1):84-88
The influence of the antitumor drugs, cyclophosphamide (CPA) and nitrosomethylurea (NMU) on the activity of lysosomal cysteine proteases cathepsin B and L in tumor tissue has been investigated using CPA-sensitive (LS) and CPA-resistant mouse lymphosarcomas (RLS). (These drugs exhibit high and low antitumor efficiency towards LS and RLS mouse lymphosarcomas, respectively). Regression or reduction in the growth rate of LS and RLS lymphosarcomas caused by CPA or NMU administration was accompanied by the increase in the activity of cysteine proteases cathepsin B and L in the tumor tissue. The increase of cathepsin B and L activity in tumor tissue correlated with the therapeutic effect of these drugs. Data obtained suggest that activity of cathepsin B and L in tumor tissue has a prognostic significance for the estimation of the effectiveness of antitumor therapy. 相似文献
884.
Natalia S. Andreeva Lev D. Rumsh 《Protein science : a publication of the Protein Society》2001,10(12):2439-2450
To elucidate the role of amino acid residues adjacent to the catalytic site of pepsin-like enzymes, we analyzed and compared the crystal structures of these enzymes, their complexes with inhibitors, and zymogens in the active site area (a total of 82 structures). In addition to the water molecule (W1) located between the active carboxyls and playing a role of the nucleophile during catalytic reaction, another water molecule (W2) at the vicinity of the active groups was found to be completely conserved. This water molecule plays an essential role in formation of a chain of hydrogen-bonded residues between the active site flap and the active carboxyls on ligand binding. These data suggest a new approach to understanding the role of residues around the catalytic site, which can assist the development of the catalytic reaction. The influence of groups adjacent to the active carboxyls is manifested by pepsin activity at pH 1.0. Some features of pepsin-like enzymes and their mutants are discussed in the framework of the approach. 相似文献
885.
Normal human blood plasma showed hydrolytic activities on several synthetic substrates for proteases, the most effective being
H-D-Ile-Pro-Arg-p-nitroanilide, H-D-Pro-Phe-Arg-p-nitroanilide and H-D-Val-Leu-Arg-p-nitroanilide. When plasma was preincubated
for 12 h at 37°C, there was no significant alteration of the hydrolytic activities. On incubation for 12 h with king cobra
venom (2 μg for 0.1 ml plasma), there was considerable decrease in the activities and complete abolition of the protease binding
capacity of α2-macroglobulin. On chromatography on Sephadex G-200, α2-macroglobulin activity and bulk of the protease activity of normal plasma were eluted in the void volume region. A minor
protease peak was eluted with aVe/Vo value of 2.5. With venom treated plasma, there was no decrease with this peak. The major protease peak and α2-macroglobulin activity were drastically reduced. Chromatography on red Sepharose showed that all the α
2
−
acroglobulin activity and bulk of the protease activity in normal plasma were bound to the column. In venom treated plasma
there was marked reduction in the bound fraction. The data suggest that cobra venom proteases directly or through proteases
generated in plasmain situ causes limited cleavage of α2-macroglobulin as well as α2-macroglobulin bound proteases, inactivating them. 相似文献
886.
A full-length cDNA encoding an aspartic protease (LeAspP) has been cloned from a tomato leaf cDNA library. Using LeAspP cDNA as a probe in gel blots, LeAspP mRNA was shown to be systemically induced in tomato leaves by wounding. Application of methyl jasmonate to leaves of intact tomato plants, or supplying systemin to young tomato plants through their cut stems, induces synthesis of LeAspP mRNA. LeAspP message is regulated in tomato similar to several systemic wound response proteins (swrps) that are part of the defense response in tomato plants directed against herbivore attacks. 相似文献