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91.
UBE1L2, a novel E1 enzyme specific for ubiquitin 总被引:1,自引:0,他引:1
Pelzer C Kassner I Matentzoglu K Singh RK Wollscheid HP Scheffner M Schmidtke G Groettrup M 《The Journal of biological chemistry》2007,282(32):23010-23014
UBE1 is known as the human ubiquitin-activating enzyme (E1), which activates ubiquitin in an ATP-dependent manner. Here, we identified a novel human ubiquitin-activating enzyme referred to as UBE1L2, which also shows specificity for ubiquitin. The UBE1L2 sequence displays a 40% identity to UBE1 and also contains an ATP-binding domain and an active site cysteine conserved among E1 family proteins. UBE1L2 forms a covalent link with ubiquitin in vitro and in vivo, which is sensitive to reducing conditions. In an in vitro polyubiquitylation assay, recombinant UBE1L2 could activate ubiquitin and transfer it onto the ubiquitin-conjugating enzyme UbcH5b. Ubiquitin activated by UBE1L2 could be used for ubiquitylation of p53 by MDM2 and supported the autoubiquitylation of the E3 ubiquitin ligases HectH9 and E6-AP. The UBE1L2 mRNA is most abundantly expressed in the testis, suggesting an organ-specific regulation of ubiquitin activation. 相似文献
92.
93.
Das Aparimita Ganesan Harsha Sriramulu Sushmitha Marotta Francesco Kanna N. R. Rajesh Banerjee Antara He Fang Duttaroy Asim K. Pathak Surajit 《Molecular and cellular biochemistry》2021,476(11):4117-4131
Molecular and Cellular Biochemistry - Oxidative stress has been known to be the underlying cause in many instances of cancer development. The new aspect of cancer genesis that has caught the... 相似文献
94.
Meena Rajesh Kumar Reddy Kanubothula Sitarami Gautam Ranjana Maddela Surender Reddy Attipalli Ramachandra Gudipalli Padmaja 《Photosynthesis research》2021,147(3):253-267
Photosynthesis Research - Heterosis is a phenomenon wherein F1 hybrid often displays phenotypic superiority and surpasses its parents in terms of growth and agronomic traits. Investigations on the... 相似文献
95.
Rajesh M.K. Radha E. Karun Anitha Parthasarathy V.A. 《Plant Cell, Tissue and Organ Culture》2003,75(1):41-47
Regeneration in oil palm was achieved through somatic embryogenesis/organogenesis from embryo-derived callus. Callus was induced from mature embryos of the cross 281 (D)×18 (P) on modified MS medium supplemented with 2,4-D (113.12 M) and 2-iP (14.76 M). The embryogenic calluses obtained were transferred to Blaydes medium supplemented with 2,4-D (0.045 M) and one of the following growth regulators: TDZ (4.54 M), zeatin riboside (2.85 M), putrescine (1 mM) and spermine (100 M). Secondary somatic embryogenesis was found to occur in media supplemented with polyamines. The efficiency of formation of somatic embryos, secondary somatic embryos and shoot meristemoids were significantly higher in putrescine containing medium. Histological studies were also undertaken. 相似文献
96.
Mohd Zeeshan Ansari Jyoti Sharma Rajesh S Gokhale Debasisa Mohanty 《BMC bioinformatics》2008,9(1):454
Background
Secondary metabolites biosynthesized by polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) family of enzymes constitute several classes of therapeutically important natural products like erythromycin, rapamycin, cyclosporine etc. In view of their relevance for natural product based drug discovery, identification of novel secondary metabolite natural products by genome mining has been an area of active research. A number of different tailoring enzymes catalyze a variety of chemical modifications to the polyketide or nonribosomal peptide backbone of these secondary metabolites to enhance their structural diversity. Therefore, development of powerful bioinformatics methods for identification of these tailoring enzymes and assignment of their substrate specificity is crucial for deciphering novel secondary metabolites by genome mining. 相似文献97.
Pseudo-peptide bond inhibitors (-bond inhibitors) and peptide-aldehyde inhibitors of atrial granule serine proteinase, the candidate processing enzyme of pro-atrial natrieuretic factor, are prepared in high yield and purity by novel synthetic routes. The -bond compounds retain essential residues for enzyme binding, but place the enzyme inhibition site in the midst of the peptide sequence. Thus, Bz-APR--LR and Bz-APR--SLRR can be considered readthrough inhibitors of atrial granule serine proteinase. The most potent -peptide, Bz-APR--SLRR (IC50=250 M), is about fivefold less potent than the best peptide-aldehyde inhibitor (EACA-APR-CHO), and both the -bond and peptide-aldehyde compounds are competitive, reversible inhibitors of the enzyme. The -bond peptides containing two C-terminal Arg residues are three-to tenfold more potent than the analogous compounds containing only one C-terminal Arg residue, confirming the importance of both Arg residues in the enzyme processing recognition site. As expected, because of their moderate potencies, the -peptides are not useful affinity ligands for purification of atrial granule serine proteinase, but both peptide aldehydes are effective affinity ligands [Damodaran and Harris (1995),J. Protein Chem., this issue].Abbreviations AGSP
atrial granule serine proteinase
- ANF
atrial natriuretic factor
- Bz
benzoyl
- DIEA
diisopropylethylamine
- DIPCDI
diisopropylcarbodiimide
- DMF
dimethylformamide
- DMSO
dimethylsulfoxide
- EACA
6(e)-aminocaproic acid
- EtOAc
ethyl acetate
- HEPES
N-2-hydroxyethylpiperazine-N-propanesulfonic acid
- HOBt
N-hydroxybenzotriazole
- HPLC
high-performance liquid chrornatography
- NMR
nuclear magnetic resonance
- PEG
polyethylene glycol-3350
- PyBOP
benzotriazole-1-yl-oxy-trispyrrolidino-phosphonium-hexafluorophospate
- TEA
triethylamine
- TFA
trifluoroacetic acid
- THF
tetrahydrofuran
- TLC
thin-layer chromatography
- UV
ultraviolet
-
pseudo-peptide bond -CH2-NH-. Single-letter abbreviations are used to denote amino acids 相似文献
98.
N-terminal sequence analysis of atrial granule serine proteinase purified by affinity chromatography
Atrial granule serine proteinase is considered the leading candidate endoproteolytic processing enzyme of pro-atrial natriuretic factor. Its cleavage specificity is directed toward a monobasic amino acid processing site, and as such, the atrial enzyme is distinguished from the family of prohormone convertases which act at dibasic amino acid processing sites. To delineate the molecular mechanisms which distinguish monobasic from dibasic amino acid-directed processing enzymes, pure atrial enzyme is needed for sequence determination leading to molecular cloning, and for preparation of antisera. An affinity chromatography purification scheme seemed a logical modification of our established procedures to yield suitable amounts of enzyme for further studies. Surprisingly, pseudo-peptide bond inhibitors of the atrial enzyme [Damodaran and Harris (1995),J. Protein Chem., this issue] formed ineffective affinity ligands, even though these compounds contain essential residues on either side of what would be the scissile bond in a peptide substrate. On the other hand, tripeptide aldehydes (based on the substrate recognition sequence of the atrial enzyme) linked to Sepharose formed effective affinity matrices, permitting purification of the enzyme in a single step from a subcellular fraction enriched for atrial granules and lysosomes. Hence, the enzyme was purified 2000-fold in 90% overall yield, and subjected to N-terminal sequence analysis through 26 residues. The sequence determined, XXPEAAGLPG[R, L]GNPVP[F, G]R[Q, I]XY[G, E]XR(N, A]V, indicates that the atrial enzyme is unique, showing little sequence homology to other proteins in the database.Abbreviations AGSP
atrial granule serine proteinase
- ANF
atrial natriuretic factor
- BSA
bovine serum albumin
-
Bz
benzoyl
- EACA
6()-aminocaproic acid
- HEPES
N-2-hydroxyethylpiperazine-N'-propanesulfonic acid
- HPLC
high-performance liquid chromatography
- PEG
polyethylene glycol-3350
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Single-letter abbreviations are used to denote amino acids 相似文献
99.
Aung Swe Rajesh Jeewon Stephen B. Pointing Kevin D. Hyde 《Biodiversity and Conservation》2009,18(6):1695-1714
Nematode-trapping fungi are ubiquitous in terrestrial habitats in dung, soils, litter and woody debris and they also occur
in freshwater, but only one species has been found in marine habitats. The purpose of this study was therefore to investigate
whether nematode-trapping fungi occurred in mangrove habitats. To achieve this we assessed the diversity of nematode-trapping
fungi on decaying litter from mangroves, freshwater and terrestrial habitats (22 sites) in Hong Kong. Composite samples (n = 1,320) of decaying litter (wood and leaves) were examined and a total of 31 species of nematode-trapping fungi belonging
to four genera, Arthrobotrys, Monacrosporium, and Dactylella were recorded. Twenty-nine species reported in this study are new records for Hong Kong and 16 species are new records from
mangrove habitats worldwide. Nematode trapping fungi are therefore present in marine environments. Commonly encountered taxa
were Arthrobotrys oligospora and Monacrosporium thaumasium which are abundant in all habitats. A. oligospora, M. thaumasium and Arthrobotrys musiformis were frequent (F > 10%). Twenty-six species were rare (0.16–9.32%). Species richness and diversity was higher in terrestrial than in freshwater
and mangrove habitats (ANOVA, P < 0.001). A higher mean diversity was observed on decaying leaves as compared to decaying wood in all habitats (P < 0.001). Based on Shannon diversity index, it was also observed that taxa characterized by adhesive nets were more frequent
in all habitats. This can be explained by the fact that these taxa may have a better competitive saprotrophic ability which
would allow them to compete favourably in nutrient limited environments. Abiotic factors that could be linked to differences
in species diversity between decaying wood and leaves are also discussed. 相似文献
100.
Pratap S. Jadon Virendra Gajbhiye Rajesh S. Jadon Kavita R. Gajbhiye Narayanan Ganesh 《AAPS PharmSciTech》2009,10(4):1186-1192
The aim of the present report was to develop nonionic surfactant vesicles (niosomes) to improve poor and variable oral bioavailability
of griseofulvin. Niosomes were prepared by using different nonionic surfactants span 20, span 40, and span 60. The lipid mixture
consisted of surfactant, cholesterol, and dicetyl phosphate in the molar ratio of 125:25:1.5, 100:50:1.5, and 75:75:1.5, respectively.
The niosomal formulations were prepared by thin film method and ether injection method. The influence of different formulation
variables such as surfactant type, surfactant concentration, and cholesterol concentration was optimized for size distribution
and entrapment efficiency for both methods. Result indicated that the niosomes prepared by thin film method with span 60 provided
higher entrapment efficiency. The niosomal formulation exhibited significantly retarded in vitro release as compared with free drug. The in vivo study revealed that the niosomal dispersion significantly improved the oral bioavailability of griseofulvin in albino rats
after a single oral dose. The maximum concentration (C
max) achieved in case of niosomal formulation was approximately double (2.98 μg/ml) as compared to free drug (1.54 μg/ml). Plasma
drug profile also suggested that the developed niosomal system also has the potential of maintaining therapeutic level of
griseofulvin for a longer period of time as compared to free griseofulvin. The niosomal formulation showed significant increase
in area under the curve0-24 (AUC; 41.56 μg/ml h) as compared to free griseofulvin (22.36 μg/ml h) reflecting sustained release characteristics. In conclusion,
the niosomal formulation could be one of the promising delivery system for griseofulvin with improved oral bioavailability
and prolonged drug release profiles. 相似文献