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991.
992.
Süleyman Can Ozturk Saniye Elvan Ozturk Ibrahim Celik Franci Stampar Robert Veberic Sami Doganlar Anita Solar Anne Frary 《Tree Genetics & Genomes》2017,13(1):16
European hazelnut (Corylus avellana L.), cultivated in several areas of the world including Europe, Anatolia, and the USA, is an economically important nut crop due to its high mineral, oleic acid, amino acid, and phenolic compound content and pleasant flavor. This study examined molecular genetic diversity and population structure of 54 wild accessions and 48 cultivars from the Slovenian national hazelnut collection using amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers. Eleven AFLP primer combinations and 49 SSR markers yielded 532 and 504 polymorphic fragments, respectively. As expected for a wind-pollinated, self-incompatible species, levels of genetic diversity were high with cultivars and wild accessions having mean dissimilarity values of 0.50 and 0.60, respectively. In general, cultivars and wild accessions clustered separately in dendrogram, principal coordinate, and population structure analyses with regional clustering of the wild material. The accessions were also characterized for ten nut and seven kernel traits and some wild accessions were shown to have breeding potential. Morphological principal component analysis showed distinct clustering of cultivars and wild accessions. An association mapping panel composed of 64 hazelnut cultivars and wild accessions had considerable variation for the nut and kernel quality traits. Morphological and molecular data were associated to identify markers controlling the traits. In all, 49 SSR markers were significantly associated with nut and kernel traits [P < 0.0001 and LD value (r 2) = 0.15–0.50]. This work is the first use of association mapping in hazelnut and has identified molecular markers associated with important quality parameters in this important nut crop. 相似文献
993.
994.
B. Syed Ibrahim N. Shamaladevi Vasantha Pattabhi 《Journal of biomolecular structure & dynamics》2013,31(6):737-744
Abstract Trypsin, a serine protease enzyme plays a pivotal role in digestion and is autocatalytic. The crystal structure of a complex formed between porcine trypsin and an auto catalytically produced peptide is reported here. This complex shows a reduction in enzyme activity as compared to native β-trypsin. The nonapeptide has a lysine, which is recognized by Asp 189 at the specificity pocket. The auto catalytically produced native nonapeptide is bound at the active site cleft like other trypsin inhibitors but the important interactions with the oxyanion hole are absent. The peptide covers only a part of the active site cleft and hence the enzyme activity is reduced rather than being inhibited. 相似文献
995.
996.
Kenneth F. Bastow Masataka Itoigawa Hiroshi Furukawa Yoshiki Kashiwada Ibrahim D. Bori Lawrence M. Ballas Kuo-Hsiung Lee 《Bioorganic & medicinal chemistry》1994,2(12):1403-1411
7-Chloro-1,3-dihydroxyacridone (1) reversibly inhibited growth of KB and vero cell lines with IC50's of 35 and 40 μM, respectively, and a topoisomerase II-mediated multidrug resistant KB sub-clone was found to be about three-fold more susceptible to 1. In contrast, two cell lines of lymphoid origin were killed following treatments with 60 μM and at higher concentrations of 1. KB cell growth inhibition correlated with a rapid, reversible suppression of thymidine incorporation. Uridine but not leucine incorporation was also rapidly suppressed. The in vitro activities of DNA topoisomerase II and novel protein kinase C-subtype delta were inhibited at effective concentrations in tissue-culture, but 1 did not stimulate intracellular protein-associated DNA breaks nor interfere initially with topoisomerase II-mediated DNA cleavage in KB cells. In addition to antiproliferative effects against cells, the compound was weakly virustatic for herpes simplex virus type I with an IC50 of 8 μM. Limited studies comparing three 1-congeners and citpressine-I, an acridone alkaloid with reported antiherpes activity, demonstrated that 7-substituted 1,3-dihydroxyacridones are novel antiproliferative agents which share similar biological and biochemical properties. 相似文献
997.
Abdullah Alaklabi Ibrahim A. Arif Anis Ahamed Radhakrishnan Surendra Kumar Akbar Idhayadhulla 《Saudi Journal of Biological Sciences》2018,25(7):1387-1392
Evaluation of antioxidant and anticancer activities were screened by various Saururus chinensis root extracts. Four solvents (ethyl acetate, methanol, ethanol, and water) extracts were investigated for their total flavonoids, phenol contents and their antioxidant activity of DPPH (2,2-diphenyl-1-picrylhydrazyl), NO (nitric oxide), H2O2 (hydrogen peroxide), ABTS 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid)diammonium assays, FRAP (ferric reducing ability of plasma) assays and anticancer activity. The total phenolic and flavonoid content of extracts were determined by using FC (Folin–Ciocalteu) and AlCl3 colorimetric assay method. Total flavonoid content in these plants ranged from 24.7 to 72.1 mg g?1 and amount of free phenolic compounds was between 11.2 and 67.1 mg g?1 extract. The all extracts have significant levels of phenolics and flavonoids content. Anticancer activity was screened for MCF-7 breast cancer cell line. Ethanol extract shows significant of antioxidant activity and water extract shows significant of anticancer activity compared with standard (BHT) butylated hydroxy toluene. These ethanol and water extracts could be considered as a natural source for using antioxidant, and anticancer agents compared to commercial available synthetic drugs. 相似文献
998.
Banana is a tropical crop cultivated in warm places. Chilling stress in Egypt is making banana crops less
productive. Abscisic acid (ABA), a key plant hormone, regulates metabolic and physiological processes and
protects plants from a variety of stresses. In vitro growing banana shoots were pre-treated with ABA at four
concentrations (0, 25, 50, and 100 mM) and chilled at 5°C for 24 h, followed by a six-day recovery period at
25°C. By comparing ABA treatments to both positive and negative controls, physiological and biochemical
changes were investigated. Chilling stress (5°C) caused a considerable increase in lipid peroxidation and ion
leakage and reduced photosynthetic pigments in cold-treated plantlets. Increasing the concentration of ABA
to 100 µM enhanced the response to chilling stress. ABA had a major effect on mitigating chilling injury in
banana shoots by keeping cell membranes stable and lowering the amount of ion leakage and lipid peroxidation.
Also, ABA significantly maintained the photosynthetic pigment concentration of banana shoots; accumulated
higher amounts of total soluble carbohydrates and proline; and increased DPPH radical scavenging activity.
Furthermore, ABA treatment enhanced cold tolerance in chilling-stressed banana shoots through the regulation
of antioxidant enzyme activity. Overall, the results show that ABA is a good choice for protecting banana shoots
from the damage caused by chilling stress. 相似文献
999.
Deutsch GB Zielonka EM Coutandin D Weber TA Schäfer B Hannewald J Luh LM Durst FG Ibrahim M Hoffmann J Niesen FH Sentürk A Kunkel H Brutschy B Schleiff E Knapp S Acker-Palmer A Grez M McKeon F Dötsch V 《Cell》2011,144(4):566-576
TAp63α, a homolog of the p53 tumor suppressor, is a quality control factor in the female germline. Remarkably, already undamaged oocytes express high levels of the protein, suggesting that TAp63α's activity is under tight control of an inhibitory mechanism. Biochemical studies have proposed that inhibition requires the C-terminal transactivation inhibitory domain. However, the structural mechanism of TAp63α inhibition remains unknown. Here, we show that TAp63α is kept in an inactive dimeric state. We reveal that relief of inhibition leads to tetramer formation with ~20-fold higher DNA affinity. In vivo, phosphorylation-triggered tetramerization of TAp63α is not reversible by dephosphorylation. Furthermore, we show that a helix in the oligomerization domain of p63 is crucial for tetramer stabilization and competes with the transactivation domain for the same binding site. Our results demonstrate how TAp63α is inhibited by complex domain-domain interactions that provide the basis for regulating quality control in oocytes. 相似文献
1000.
Ibrahim A. I. Ali 《Nucleosides, nucleotides & nucleic acids》2013,32(3):129-140
A series of quinoxaline azido reverse nucleosides 3a-c and their O-regioisomers 4a-c was prepared by reaction of quinoxaline 1a-c with 3-azido-3-deoxy-1,2-O-isopropylidene-5-p-toluenesulfonyl-D-ribofuranose (2) in the presence of sodium hydride. Structure modification of these interesting structures includes reduction and the subsequent acetylation reactions to give quinoxaline amino and acetyl amino reverse nucleosides and their O-regioisomers. 相似文献