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991.
Abad Khan Muhammad I. Khan Zafar Iqbal Yasar Shah Lateef Ahmad David G. Watson 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(25):2339-2347
A novel, simple and fast reversed-phase HPLC/UV method was developed, optimized for various chromatographic conditions, and validated according to international guidelines for simultaneous determination of all-trans-retinol and α-tocopherol in human serum using retinyl acetate as internal standard in the concentration of 0.5 μg/ml. A liquid-phase extraction was applied to the 250 μl of serum with n-hexane–dichloromethane mixture (70:30, v/v), in two steps, using ethanol–methanol mixture (95:5, v/v) for protein precipitation and BHT (butylated hydroxy toluene) as stabilizer for sample preparation. Both analytes were analyzed on Kromasil 100 C18 column (150 mm × 4.6 mm, 5 μm), Brownlee analytical (Perkin Elmer) C18 column (150 mm × 4.6 mm, 5 μm), and Supelco (Supelcosil) LC-18 column (150 mm × 3 mm, 3 μm), protected by a Perkin Elmer C18 (30 mm × 4.6 mm, 10 μm; Norwalk, USA) pre-column guard cartridge, at 292 nm wavelength, using methanol–water (99:1, v/v), in isocratic mode as mobile phase applied at flow rate of 1.5 ml/min and 1 ml/min for both 5 μm and 3 μm columns, respectively. Complete separation of all the analytes was achieved in 3 and 6 min on 3 μm and 5 μm columns, respectively by injecting 20 μl of sample into the HPLC system by autosampler, keeping column oven temperature at 25 °C. Different particulate reversed-phase chromatographic columns were evaluated in order to select the best column in terms of sensitivity, selectivity, resolution and short run time of both the analytes and it was concluded that 3 μm columns are better to be used in clinical set up as well as in laboratories for the separation of these analytes in a shorter time as compared with 5 μm columns. The method was validated and applied for the analysis of all-trans-retinol and α-tocopherol in the serum of human volunteers. 相似文献
992.
Muhammad Farooq Sabar Mustansara Yaqub Mohsin Ahmad Khan Nadeem Ahmad Muhammad Usman Ghani Mariam Shahid 《International journal of peptide research and therapeutics》2010,16(4):239-245
Efficacy of proteins can be enhanced by using polyethylene glycol (PEG) conjugation (PEGylation) to the protein molecules.
Mobile non-toxic PEG chains conjugated to bio-therapeutics increase their hydrodynamic volume and in turn can prolong their
plasma retention time and increase their solubility. An important aspect of PEGylation is the selection of PEG molecule with
suitable structure and molecular weight. In this study, conceiving the idea that branched PEG-conjugates show superior efficacy
over the linear PEG-conjugates, a tri-branched PEG-interferon (mPEG3L2-IFN) was synthesized by reacting a 30 KDa tri-branched mPEG3L2-NHS reagent with IFN to improve its pharmacokinetic properties and reduce the loss of in vitro bioactivity (which is generally
exhibited by PEGylation) of the conjugated protein to some extent. The PEGylation procedure was optimized in terms of concentration
and molar ratios of reactants, reaction time, temperature and pH conditions of the reaction mix. The conjugate was purified
by cation exchange chromatography and characterized by SDS-PAGE and SE-HPLC. Trypsin digestion of mPEG3L2-IFN indicated a single site specificity of PEGylation. Anti viral bioactivity of mPEG3L2-IFN was found to be 2.38 × 107 IU/mg which is approximately 9.52% of native IFNα2 (2.5 × 108 IU/mg) and better than PEGasys from Roche Pharma. Therefore, it is reported that the tri-branched mPEG3L2-NHS reagent has the potential to be used to conjugate proteins for the promising therapeutic results. 相似文献
993.
The presence of toxic heavy metals in natural environments entails a potential health hazard for humans. Metal contaminants in these environments are usually tightly bound to colloidal particles and organic matter. On the other hand, the potential of these metals towards chelation by different chelating agents presents a good characteristic for their removal from the environment. On this basis, two chitosan/anionic surfactant complexes were prepared and evaluated for their ability to remove heavy metals from aqueous solutions. The experimental results of the uptake of metal ions including Cu2+, Sn2+, Co2+ and Ni2+ are reported in this study. The results show that modified chitosan with short‐spacer group cross‐linkers has a higher potential for heavy metal uptake than long‐chain cross‐linker‐modified chitosan. Also, increasing the electronegativity of the heavy metals increases their uptake from the medium. Increasing the time of exposure of the heavy metals to the modified polymer increases the efficiency of the metal uptake process. 相似文献
994.
Heshmat Omidi Zeinaldin Tahmasebi Hassan Ali Naghdi Badi Hossein Torabi Mohammad Miransari 《Comptes rendus biologies》2010,333(3):248-254
Vegetable oils with a high relative amount of unsaturated fatty acids are of great significance for human health. There is not any data on the effects of tillage practices on fatty acid composition of canola (Brassica napus L.). Hence, in a 2-year split plot experiment, the effects of different tillage systems (no (NT), minimum (MT) and conventional tillage (CT)), canola genotypes (Hyola 401 (V1) and PF (V2)) and sowing dates (including Sep. 8, 23 and Oct. 7) on the fatty acid composition of canola were evaluated. Tillage practices and the combination of canola genotypes and sowing dates were randomized to the main and sub-plots, respectively. The highest oleic acid content was the result of combining NT, V1 and Sep. 23, and the lowest was related to the combination of CT, V2 and Oct. 7. While the combination of NT, V1 and D1 resulted in the highest amount of unsaturated fatty acids, this amount was the lowest for the combination of CT, V2 and Sep. 23. For the selection of an appropriate canola producing strategy, all these parameters must be taken into account. The combination of NT, V1 and Sep. 23 may be the most favorable cropping strategy for canola production under a Mediterranean climate. 相似文献
995.
Growth performance, chromium (Cr) accumulation potential and induction of antioxidative defence system and phytochelatins
(PCs) were studied in hydroponically grown Brassica juncea (Indian mustard) and Vigna radiata (mungbean) at various levels of Cr treatments (0, 50, 100, 200 μM Cr). B. juncea accumulated twofolds and threefolds higher Cr in root and shoot, respectively than in V. radiata. Compared to B. juncea, V. radiata was found to be particularly sensitive to Cr as observed by the severity and development of Cr toxicity symptoms and decreased
growth. Induction of PC and enzymes of antioxidant defence system were monitored as plant’s primary and secondary metal detoxifying
responses, respectively. There was induction of PC and enzymes of antioxidant defence system in both the plants. PCs were
induced significantly in roots and shoot of both the plants at all the levels of Cr treatments. Significantly higher activities
of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR) were observed in
shoot of B. juncea than V. radiata at all the levels of Cr treatments. Induction of PCs along with antioxidant defence system in response to Cr stress suggests
the cumulative role of PCs and antioxidants in conferring tolerance against accumulated Cr in B. juncea, and thereby signifies the suitability of this plant as one of the potential remediators of Cr. 相似文献
996.
The indigenous forage grasses Lasiurus scindicus and Panicum turgidum are candidate species for the restoration of degraded desert rangelands. The impact of five dormancy regulating chemicals on overcoming salinity-induced germination inhibition was assessed under the best germination conditions in the two species. Seeds were germinated in a series of NaCl concentrations: 0–200 mM NaCl for P. turgidum, and 0–300 mM NaCl for L. scindicus. Lasiurus scindicus seeds were more tolerant to salinity than those of P. turgidum. Twenty percent of P. turgidum seeds germinated in 100 mM NaCl and none in the higher levels, but 47.5% and 8.8% of L. scindicus seeds germinated in 100 and 200 mM NaCl, respectively. The five studied chemicals (fusicoccin, GA3, kinetin, nitrate and thiourea) did not succeed in improving germination of non-saline treated seeds of the two species, compared to the control, except thiourea in P. turgidum. The salinity-induced germination inhibition in P. turgidum was completely alleviated by the application of gibberellic acid (GA3), partially alleviated by the application of fusicoccin, kinetin and thiourea, but not affected by nitrate. In L. scindicus, the germination inhibition was completely alleviated by fusicoccin, GA3, nitrate and thiourea, but partially alleviated by kinetin. For using the two grass species in restoration of degraded rangelands affected by higher salinity, the results suggest using fusicoccin, GA3, nitrate and thiourea with L. scindicus and GA3 with P. turgidum seeds as a preseeding treatment can overcome the problem of reduced germination. 相似文献
997.
Mauricio Hunsche Kathrin Bürling Amina Sirag Saied Michaela Schmitz-Eiberger Muhammad Sohail Jens Gebauer Georg Noga Andreas Buerkert 《Plant Growth Regulation》2010,61(3):253-263
Seedlings of the salt-tolerant plant grewia [Grewia tenax (Forssk.) Fiori] and the moderately salt-tolerant tamarind (Tamarindus indica L.) were grown under controlled conditions and treated daily with NaCl solutions to investigate mechanisms of tolerance to
salinity. Leaf micromorphology, cuticular wax load, chlorophyll fluorescence and light remission, as well as antioxidative
potential were evaluated. As confirmed by energy-dispersive X-ray microanalysis in both species, absorption of sodium and
chlorine increased with rising NaCl concentration in the treatment solution. In parallel, accumulation of calcium in grewia
leaves was strongly reduced, leading to less crystals of calcium oxalate in leaf tissue. In grewia the cuticular wax load,
chlorophyll content, and electron transport rate (ETR) were significantly reduced by comparatively low NaCl concentrations.
In tamarind, in contrast, wax load and ETR were not significantly affected, while the decrease of chlorophyll content was
less pronounced. Measurements of the antioxidative capacity and the imbalance between values of lipophilic and hydrophilic
extracts at different NaCl concentrations confirmed that grewia is more salt tolerant than tamarind. This higher tolerance
degree seemed to be associated with grewias’ more efficient scavenging of free radicals and the regulation of the antioxidative
potential in lipophilic and hydrophilic extracts. 相似文献
998.
Khadijeh Zare Hossein Nazemiyeh Ali Movafeghi Mahmood Khosrowshahli Alireza Motallebi-Azar Mohammadreza Dadpour Yadollah Omidi 《Plant Cell, Tissue and Organ Culture》2010,100(2):157-164
An in vitro cell suspension culture of Echium italicum was established and assayed for the production of shikonin and alkannin derivatives. Callus tissues were induced from cotyledon
explants of the plant incubated onto the solidified B5 medium. A two-liquid-phase system suspension culture was then established
to elicit pigments of shikonin and alkannin derivatives using liquid paraffin. The presence of liquid paraffin efficiently
induced production of pigments in cultured cells. The production and/or accumulation of these compounds in the E. italicum cells was examined using fluorescence microscopy as the naphthoquinone molecules display autofluorescent properties. Phytochemical
analysis of the n-hexane extract of the medium was also carried out using preparative HPLC. The chemical structure of shikonin and alkannin
derivatives were characterized by UV, 1H-NMR, and 13C-NMR techniques. Based on our findings, this bioprocess engineering approach
resulted in induction of shikonin and alkannin derivatives, whereupon it may be recruited for production of these important
secondary metabolites. 相似文献
999.
Zahra Yazdanbakhsh Masoud Sheidai Ramezan‐Ali Khavarinejad Maryam Keshavarzi Taher Nejadsattarei 《Nordic Journal of Botany》2010,28(4):432-437
Meiotic studies were performed in twelve populations of four Oryzopsis species (O. pubiflora, O. lateralis, O. holciformis var. longiglomis and O. barbellata) to obtain data on the ploidy level and cytological evolution of the genus. The chromosome number 2n=2x=24 was revealed in all the species and populations studied. The present and other studies show the occurrence of two basic chromosome numbers in the genus, i.e. x=11 and x=12. Although Oryzopsis species and populations studied are diploid and are expected to form only bivalents in metaphase of meiosis‐I, quadrivalents were observed in O. pubiflora and O. lateralis, possibly due to the occurrence of heterozygote translocations. B‐chromosomes of 0–2 were observed in all species and populations studied. This is the first report of the occurrence of B‐chromosomes in the genus Oryzopsis. Several meiocytes showed the presence of double chromosome number in O. lateralis, and multipolar cells were observed in populations of O. barbellata, O. lateralis and O. holciformis var. longiglomis. The occurrence of large pollen grains (possibly unreduced) was observed along with smaller (normal) pollen grains in these species. Significant differences observed in chiasma frequency and distribution among studied species may be of use in species delimitation. The Kakan population differed significantly from the other populations of O. lateralis in meiotic characteristics. If such cytological differences are accompanied by morphological variation (under investigation), we may consider this population as a new variety or subspecies. 相似文献
1000.
Bacillus licheniformis, B. subtilis, B. cereus, Bacillus pumilus and Exiguobacterium sp., which were resistant up to 20 mg Na2SeO3/ml in nutrient broth and 40 mg/ml on nutrient agar plates, were isolated from contaminated soil and water. They grew from
25 to 45°C and pH 5 to 9. They had multiple metal and antibiotic resistances. All strains reduced selenite (SeIV) to elemental
selenium (Se0) aerobically with a maximum reduction of 97% by B. pumilus after 144 h with Na2SeO3 at 500 μg/ml. 相似文献