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93.
Talita A. Sampaio e Silva Adriana Knob Célia R. Tremacoldi Marcia R. Brochetto-Braga Eleonora Cano Carmona 《World journal of microbiology & biotechnology》2011,27(11):2491-2497
Acid proteases represent an important group of enzymes, widely used in food, beverage and pharmaceutical industries. For most
of these applications the enzymatic preparation must be at least partially purified and free of substances that could change
the characteristics of the product or the process. Fungal proteases have replaced other sources because they are easily obtained
mainly from Mucor, Rhizopus, Penicillium
and
Aspergillus species. A strain of Aspergillus
clavatus was selected by producing high level of acid protease activity. An extracellular aspartatic protease from this strain was
purified 37.2 times with 37% recovery using (NH4)2SO4 fractionation and ion-exchange chromatography. The enzyme was found to be monomeric having a molecular mass of 30.4 kDa.
The purified enzyme is an acid protease with optimum pH of 5.5 and temperature for optimum activity of 50 °C. Its high pH
stability was verified in the range of 3.5–6.5. The acid protease was strongly inhibited by Hg+2 and partially inhibited by Cu+2, Zn+2 and Mn+2. The enzyme was sensitive to denaturing agent SDS and activated by thiol-containing reducing agent dithiotreitol (DTT). The
protease activity was not influenced by iodoacetic acid, E-64 and PMSF, while it was lightly actived by EDTA and totally inhibited
by pepstatin, with a Ki of 7.8 μM, indicating that is an aspartic protease. A.
clavatus acid protease presents interesting characteristics for biotechnological process, such as cheese and flavor manufacture and
dietary supplements, in which activity and stability in acid pH are required. 相似文献
94.
Goi G Massaccesi L Burlina AP Baquero Herrera CJ Lombardo A Tettamanti G Burlina AB 《Biochimica et biophysica acta》2005,1741(3):300-306
OBJECTIVE: Fabry disease results from a deficiency in the activity of alpha-d-galactosidase A and subsequent accumulation of neutral glycosphingolipids in lysosomes. This study investigated whether lysosomal enzymes can indicate biochemical changes in the lysosomal apparatus induced by enzyme replacement therapy (ERT). DESIGN AND METHODS: Eight patients were monitored by clinical and biochemical tests and several lysosomal glycohydrolases were measured in plasma and leucocytes. RESULTS: Before starting ERT, beta-d-glucuronidase in leukocytes was markedly increased. After 1 month of therapy, enzyme levels dropped in all patients. In the patients who regularly followed the therapy, the enzyme levels remained stable for the next 20 months. In one patient who interrupted therapy for 2 months, the enzyme levels rose again. CONCLUSIONS: Lysosomal enzymes can be useful for monitoring biochemical changes in patients with Fabry disease receiving ERT. Though these findings refer to only a small number of patients, the correlation between beta-d-glucuronidase levels and ERT is interesting and might serve as a basis for further studies to define the potential of this enzyme in monitoring the effects of ERT in lysosomal storage disorders. 相似文献
95.
Janet Jan-Roblero Adriana Posadas Javier Zavala Díaz de la Serna Rafael García César Hernández-Rodríguez 《World journal of microbiology & biotechnology》2008,24(9):1775-1784
Characterization of the microbial populations formed in gas pipelines is essential to understand the metallic surface-microbe
interaction, their role in metal corrosion, and to implement efficient monitoring and control strategies. Microbial community
analysis in a corroded gas pipeline in a petroleum-producing facility in the Southeast region in Mexico was performed by traditional
cultivation techniques and identification based on 16S rRNA gene sequence. In all samples, thin bacterial biofilms were observed
and pitting corrosion was reveled after removing the biofilms. Six pure or mixed cultures of anaerobic bacteria were obtained
and their 16S rRNA libraries were constructed, respectively. At least two members of each RFLP profile were sequenced and
the phylogenetic affiliations of cloned bacterial 16S rRNA genes indicated that native biofilms were mainly colonized by Desulfovibrio vulgaris and Desulfovibrio
desulfuricans, sulfate-reducing bacteria members; Citrobacter freundii, an Enterobacteriaceae member; Clostridium celerecrescens and Clostridium sporogenes, spore-forming anaerobic species and Cetobacterium somerae, a microaerotolerant, non-spore-forming fusobacteria. Some of these species have been observed consistently in other steel
pipelines previously, but Cetobacterium members and C.
celerecrescens are described for the fist time in this corroded gas pipeline. The potential role of each species in biofilm formation and
steel corrosion is discussed. 相似文献
96.
Carmen Attolini Giorgio Mazza Adriana Fortunato Giovanni Ciarrocchi Giorgio Mastromei Silvano Riva Arturo Falaschi 《Molecular & general genetics : MGG》1976,148(1):9-17
Summary The dnaP strains of Bacillus subtilis are altered in the initiation of DNA replication at high temperature (Riva et al., 1975). Fine mapping of the gene shows that it is located very close to the dnaF gene, described by Karamata and Gross (1970) and mapped by Love et al. (1976) in the polC region. The phenotype of both mutants is indistinguishable: the DNA synthesis stops at non permissive temperature after synthesizing an amount of DNA equivalent to the completion of the rounds of replication already initiated; at permissive temperature they are abnormally sensitive to MMS and are reduced in the ability to be transformed. Both mutants are to be considered as belonging to the dnaF locus.The dnaF gene is very close to the polC gene, which specifies the DNA polymerase III of B. subtilis. The DNA polymerase III of the dnaF mutants is not temperature sensitive in vitro, however, the level of this enzyme is lower by a factor of 4 or 5 in the dnaF mutants, at the permissive temperature. Following shift of dnaF cultures to the non permissive temperature, the level of DNA polymerase III activity specifically decreases further by a factor of at least 10 in the mutant, whereas the DNA polymerase I level is unaffected.The possible roles of the dnaF gene in the control of the cellular level of the DNA polymerase III, and the possibility of a regulatory role of DNA polymerase III in the initiation of DNA replication in bacteria are discussed.Abbreviations and symbols HPUra
6-(p-hydroxyphenylazo)-uracil; mic, minimum inhibitory concentration
- MMS
methyl-methanesufonate
- Pol I
Pol II and Pol III: DNA polymerase I, II and III respectively
- PCMB
parachloro-mercuri-benzoate 相似文献
97.
Katarína Střelcová Daniel Kurjak Adriana Leštianska Dana Kovalčíková Ľubica Ditmarová Jaroslav Škvarenina Yousif Abdel-Rahman Ahmed 《Biologia》2013,68(6):1118-1122
The paper focuses on the evaluation of transpiration as a physiological process, which is very sensitive to drought stress. Reactions of 25-year-old Norway spruce (Picea abies (L.) Karst.) trees to drought were examined during 2009 summer. Sap flow rate (SF), meteorological and soil characteristics were measured continually. Vapour pressure deficit of the air (VPD) and cumulative transpiration deficit (KTD) was calculated. During the second half of the vegetation period, the decrease in soil water content was observed and irrigation was applied to a group of spruce trees, while the second group was treated under natural soil drought. On the days, when the differences in transpiration between irrigated (IR) and non-irrigated (NIR) trees were significant (21 days), transpiration of NIR trees was only 23% of the transpiration of IR trees. We found significant differences in transpiration when the soil water content (SWC) of NIR variant at a depth of 5–15 cm ranged from 10.4 to 13.7%. Under both regimes of water availability, daily transpiration significantly responded to atmospheric conditions. However, the influence of all assessed meteorological parameters on SF of NIR trees was significantly lower than on IR tree. The dependency of transpiration on evaporative demands of atmosphere decreased with the decreasing soil moisture. Cumulative transpiration deficit of the stand during the entire evaluated period was 50.9 mm. The difference between the transpiration of the mean NIR tree and of the mean IR tree was 278.8 L over the assessed period of 47 days (5.9 L per day). The transpiration of NIR trees was 40.3% from the transpiration of IR trees during this period. 相似文献
98.
Patricia de Souza Bonfim-Mendon?a Bianca Altr?o Ratti Janine da Silva Ribeiro Godoy Melyssa Negri Nayara Cristina Alves de Lima Adriana Fiorini Elaine Hatanaka Marcia Edilaine Lopes Consolaro Sueli de Oliveira Silva Terezinha Inez Estivalet Svidzinski 《PloS one》2014,9(9)
Vulvovaginal candidiasis (VVC) is among the most prevalent vaginal diseases. Candida albicans is still the most prevalent species associated with this pathology, however, the prevalence of other Candida species, such as C. glabrata, is increasing. The pathogenesis of these infections has been intensely studied, nevertheless, no consensus has been reached on the pathogenicity of VVC. In addition, inappropriate treatment or the presence of resistant strains can lead to RVVC (vulvovaginal candidiasis recurrent). Immunomodulation therapy studies have become increasingly promising, including with the β-glucans. Thus, in the present study, we evaluated microbicidal activity, phagocytosis, intracellular oxidant species production, oxygen consumption, myeloperoxidase (MPO) activity, and the release of tumor necrosis factor α (TNF-α), interleukin-8 (IL-8), IL-1β, and IL-1Ra in neutrophils previously treated or not with β-glucan. In all of the assays, human neutrophils were challenged with C. albicans and C. glabrata isolated from vulvovaginal candidiasis. β-glucan significantly increased oxidant species production, suggesting that β-glucan may be an efficient immunomodulator that triggers an increase in the microbicidal response of neutrophils for both of the species isolated from vulvovaginal candidiasis. The effects of β-glucan appeared to be mainly related to the activation of reactive oxygen species and modulation of cytokine release. 相似文献
99.
Adriana Calderaro Giovanna Piccolo Chiara Gorrini Sara Montecchini Sabina Rossi Maria Cristina Medici Carlo Chezzi Georges Snounou 《PloS one》2012,7(10)
It has been proposed that ovale malaria in humans is caused by two closely related but distinct species of malaria parasites: P. ovale curtisi and P. ovale wallikeri. We have extended and optimized a Real-time PCR assay targeting the parasite’s small subunit ribosomal RNA (ssrRNA) gene to detect both these species. When the assay was applied to 31 archival blood samples from patients diagnosed with P. ovale, it was found that the infection in 20 was due to P. ovale curtisi and in the remaining 11 to P. ovale wallikeri. Thus, this assay provides a useful tool that can be applied to epidemiological investigations of the two newly recognized distinct P. ovale species, that might reveal if these species also differ in their clinical manifestation, drugs susceptibility and relapse periodicity. The results presented confirm that P. ovale wallikeri is not confined to Southeast Asia, since the majority of the patients analyzed in this study had acquired their P. ovale infection in African countries, mostly situated in West Africa. 相似文献
100.
Franco Chimenti Daniela Secci Adriana Bolasco Paola Chimenti Arianna Granese Simone Carradori Elias Maccioni M. Cristina Cardia Matilde Yáñez Francisco Orallo Stefano Alcaro Francesco Ortuso Roberto Cirilli Rosella Ferretti Simona Distinto Johannes Kirchmair Thierry Langer 《Bioorganic & medicinal chemistry》2010,18(14):5063-5070
The present study reports on synthesis in high yields (70–99%), HPLC enantioseparation, inhibitory activity against human monoamino oxidases, and molecular modeling including 3D-QSAR studies, of a large series of (4-aryl-thiazol-2-yl)hydrazones (1–45). Most of the synthesized compounds proved to be potent and selective inhibitors of hMAO-B isoform in the micromolar or nanomolar range, thus demonstrating that hydrazothiazole could be considered a good pharmacophore to design new hMAO-B inhibitors. Due to the presence in some derivatives of a chiral center, we also performed a semipreparative chromatographic enantioseparation of these compounds obtained by a stereoconservative pattern. The separated enantiomers were submitted to in vitro biological evaluation to point out the stereorecognition of the active site of the enzyme towards these structures. Finally, a 3D-QSAR study was carried out using Comparative Molecular Field Analysis (CoMFA), aiming to deduce rational guidelines for the further structural modification of these lead compounds. 相似文献