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991.
In order to determine if the infectious pancreatic necrosis virus isolate IPNV-Jasper (Ja-ATCC) is homogeneous or heterogeneous with respect to inhibition by normal rainbow trout serum (RTS), 50 clones were tested for sensitivity to RTS. The initial isolate was very sensitive to RTS, losing from 10(4) to 10(8) 50 % tissue culture infection dose (TCID50) ml(-1) with a 1:100 dilution of RTS. The sensitivity of the clones ranged from highly sensitive to completely resistant (0 to 10(8) TCID50 ml(-1) reduction). Eight percent of clones (4/50) were very sensitive to RTS (Ja-S) and 84% of clones (42/50) showed a mid-range of sensitivity to RTS. The final 8 % of clones (4/50) were resistant to RTS (Ja-R). Enzyme immunodot assay revealed that Ja-S clones showed a monoclonal reaction identical to the parents, Ja-ATCC; however, Ja-R clones differed by several epitopes from the parental strain. Analysis of Ja-S and Ja-R revealed that there were significant differences in their nucleic acid sequences for the capsid protein VP2. These 2 strains shared 80.7 and 86.5% identity in nucleic acid and in amino acid sequences, respectively. Ja-S had 99.7 and 91.0 % identity in nucleic acid sequences, and 99.5 and 95.9 % in amino acid sequences with Ja-ATCC and Jasper-Dobos (Ja-D), respectively, while Ja-R showed 80.6 and 79.8 % identity in nucleic acid sequences and 86.5 and 87.0 % in amino acid sequences with Ja-ATCC and Ja-D, respectively. In conclusion, the Ja-ATCC population was heterogeneous in terms of RTS sensitivity, serotype and cDNA sequences from the VP2 coding region. 相似文献
992.
Large-conductance voltage and Ca2+-activated potassium channels (BKCa) play a critical role in modulating contractile tone of smooth muscle, and neuronal processes. In most mammalian tissues, activation of β-adrenergic receptors and protein kinase A (PKAc) increases BKCa channel activity, contributing to sympathetic nervous system/hormonal regulation of membrane excitability. Here we report the requirement of an association of the β2-adrenergic receptor (β2AR) with the pore forming α subunit of BKCa and an A-kinase-anchoring protein (AKAP79/150) for β2 agonist regulation. β2AR can simultaneously interact with both BKCa and L-type Ca2+ channels (Cav1.2) in vivo, which enables the assembly of a unique, highly localized signal transduction complex to mediate Ca2+- and phosphorylation-dependent modulation of BKCa current. Our findings reveal a novel function for G protein-coupled receptors as a scaffold to couple two families of ion channels into a physical and functional signaling complex to modulate β-adrenergic regulation of membrane excitability. 相似文献
993.
Ring-shaped architecture of RecR: implications for its role in homologous recombinational DNA repair 下载免费PDF全文
RecR, together with RecF and RecO, facilitates RecA loading in the RecF pathway of homologous recombinational DNA repair in procaryotes. The human Rad52 protein is a functional counterpart of RecFOR. We present here the crystal structure of RecR from Deinococcus radiodurans (DR RecR). A monomer of DR RecR has a two-domain structure: the N-terminal domain with a helix-hairpin-helix (HhH) motif and the C-terminal domain with a Cys4 zinc-finger motif, a Toprim domain and a Walker B motif. Four such monomers form a ring-shaped tetramer of 222 symmetry with a central hole of 30-35 angstroms diameter. In the crystal, two tetramers are concatenated, implying that the RecR tetramer is capable of opening and closing. We also show that DR RecR binds to both dsDNA and ssDNA, and that its HhH motif is essential for DNA binding. 相似文献
994.
Bioconversion of waste office paper to L(+)-lactic acid by the filamentous fungus Rhizopus oryzae 总被引:4,自引:0,他引:4
L(+)-lactic acid production was investigated using an enzymatic hydrolysate of waste office automation (OA) paper in a culture of the filamentous fungus Rhizopus oryzae. In 4 d culture, 82.8 g/l glucose, 7 g/l xylose, and 3.4 g/l cellobiose contained in the hydrolysate were consumed to produce 49.1 g/l of lactic acid. The lactic acid yield and production rate were only 0.59 g/g and 16.3 g/l/d, respectively, only 75% and 61% of the results from the glucose medium. The low production rate from waste OA hydrolysate was elucidated by trials using xylose as the sole carbon source; in those trials, the lactic acid production rate was 7.3 g/l/d, only 28% that of glucose or cellobiose. The low lactic acid yield from waste OA hydrolysate was clarified by trials using artificial hydrolysates comprised of 7:2:1 or 7:1:2 ratios of glucose:cellobiose:xylose. For both, the lactic acid production rate of 17.4 g/l/d matched that of waste OA paper, while the lactic acid yield was similar to that of the glucose medium. This indicates that the production rate may be inhibited by xylose derived from hemicellulose, and the yield may be inhibited by unknown compounds derived from paper pulp. 相似文献
995.
Lee SK Park EJ Lee E Min HY Kim EY Lee T Kim S 《Bioorganic & medicinal chemistry letters》2004,14(9):2105-2108
The inhibitory effects of a series of styrylheterocycles on the production of cyclooxygenase-2-mediated prostaglandin E(2) (PGE(2)) were evaluated in lipopolysaccharide-stimulated RAW264.7 murine macrophages. A new series of potential inhibitors, including 3-[2-(4-methoxy-phenyl)-vinyl]-thiophene, have been identified, thus providing novel chemical leads for the further development of potential inhibitors in this capacity. The suppression of COX-2 mRNA expression by the active styrylheterocycles, in part, was involved in the inhibitory activity against the overproduction of PGE(2). 相似文献
996.
Stearns BA Anker N Arruda JM Campbell BT Chen C Cramer M Hu T Jiang X Park K Ren KK Sablad M Santini A Schaffhauser H Urban MO Munoz B 《Bioorganic & medicinal chemistry letters》2004,14(5):1295-1298
A novel class of 6-aryl-6H-pyrrolo[3,4-d]pyridazine ligands for the alpha2delta subunit of voltage-gated calcium channels has been described. Substitutions in the aryl ring of the molecule were generally not tolerated, and resulted in diminished binding to the alpha2delta subunit. Modifications to the pyridazine ring revealed numerous permissive substitutions, and detailed SAR studies were carried out in this portion of the molecule. Replacement of the pyridazine ring methyl group with an aminomethyl functionality provided greatly improved potency over the initial lead. The initial lead compound displayed good rat pharmacokinetic properties, and was shown to be efficacious in the Chung model for neuropathic pain in rats. 相似文献
997.
Lee WS Lee DW Baek YI An S An SJ Cho KH Choi YK Kim HC Park HY Bae KH Jeong TS 《Bioorganic & medicinal chemistry letters》2004,14(12):3109-3112
The sesquineolignan, saucerneol B (1), and dineolignans, manassantin A (2), and manassantin B (3), were isolated from the methanol extracts of Saururus chinensis root and elucidated by their spectroscopic data analysis. Compounds 1-3 inhibited hACAT-1 and hACAT-2 with IC(50) values of 43.0 and 124.0 microM for 1, of 39.0 and 8.0 microM for 2, of 82.0 microM and only 32% inhibition at 1mM for 3, respectively. The EtOAc-soluble fraction, which contained compounds 1-3, of methanol extracts of S. chinensis exhibited strong cholesterol-lowering effect in high cholesterol-fed mice. 相似文献
998.
Park HG Choi JY Choi SH Park MK Lee J Suh YG Cho H Oh U Kim HD Joo YH Kim SY Park YH Jeong YS Choi JK Kim JK Jew SS 《Bioorganic & medicinal chemistry letters》2004,14(7):1693-1696
A series of N-4-methansulfonamidobenzyl-N'-2-substituted-4-tert-butylbenzyl thioureas were prepared for the study of their agonistic/antagonistic activities to the vanilloid receptor in rat DRG neurons. Their structure-activity relationship reveals that there is a space for another hydrophobic binding interaction around 2-position in 4-tert-butylbenzyl region. Among the prepared derivatives, 6n show the highest antagonistic activity against the vanilloid receptor (IC(50)=15 nM). 相似文献
999.
Synthesis and biological activity of new quinoxaline antibiotics of echinomycin analogues 总被引:5,自引:0,他引:5
Novel quinoxaline antibiotics having the methylenedithioether bridge as an analogue of echinomycin have been synthesized by insertion of methylene moiety between -S-S- bond. The compound 1a shows remarkable cytotoxicities against human tumor various cell lines, and is active VRE (vancomycin-resistant enterococci) within MIC range 0.5-8 microg/mL. According to the eukaryotic or prokaryotic data, 1a might be a first analogue to replace echinomycin. 相似文献
1000.
Park HG Choi JY Choi SH Park MK Lee J Suh YG Cho H Oh U Lee J Kang SU Lee J Kim HD Park YH Su Jeong Y Kyu Choi J Jew SS 《Bioorganic & medicinal chemistry letters》2004,14(3):787-791
A series of N-4-substituted-benzyl-N'-tert-butylbenzyl thioureas were prepared for the study of their agonistic/antagonistic activities to the vanilloid receptor in rat DRG neurons. Their structure-activity relationship reveals that not only the two oxygens and amide hydrogen of sulfonamido group, but also the optimal size of methyl in methanesulfonamido group play an integral role for the antagonistic activity on vanilloid receptor. 相似文献