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991.
992.
Linkage of familial Hibernian fever to chromosome 12p13. 总被引:2,自引:0,他引:2
M F McDermott B W Ogunkolade E M McDermott L C Jones Y Wan K A Quane J McCarthy M Phelan M G Molloy R J Powell C I Amos G A Hitman 《American journal of human genetics》1998,62(6):1446-1451
Autosomal dominant periodic fevers are characterized by intermittent febrile attacks of unknown etiology and by recurrent abdominal pains. The biochemical and molecular bases of all autosomal dominant periodic fevers are unknown, and only familial Hibernian fever (FHF) has been described as a distinct clinical entity. FHF has been reported in three families-the original Irish-Scottish family and two Irish families with similar clinical features. We have undertaken a genomewide search in these families and report significant multipoint LOD scores between the disease and markers on chromosome 12p13. Cumulative multipoint linkage analyses indicate that an FHF gene is likely to be located in an 8-cM interval between D12S77 and D12S356, with a maximum LOD score (Z max) of 3.79. The two-point Z max was 3.11, for D12S77. There was no evidence of genetic heterogeneity in these three families; it is proposed that these markers should be tested in other families, of different background, that have autosomal dominant periodic fever, as a prelude to identification of the FHF-susceptibility gene. 相似文献
993.
Misicka Aleksandra Verheyden Patricia M.F. Van Binst Georges 《International journal of peptide research and therapeutics》1998,5(5-6):375-377
Summary The conformationalcis-trans equilibrium around the peptide bond in model tripeptides has been determined by 2D NMR methods (HOHAHA, ROESY). The study
was limited to three different N-substituted amino acids in position 2, namely Pro (proline), Tic (1,2,3,4-tetrahydroisoquinoline-3-carboxylic
acid), and N-MePhe (N-methylphenylalanine). In all cases the amino acid in position 1 was tyrosine and in position 3, phenylalanine. The results
of our studies show that thecis-trans ratio depends mostly on the configuration of the amino acids forming the peptide bond undergoing thecis-trans isomerisation. The amino acid following the sequence (in position 3) does not have much influence on thecis-trans isomerisation, indicating that there is no interaction of the side chains between these amino acids. The model peptides with
the L-Tyr-L-AA-(L-or D-)Phe (where AA is N-substituted amino acid) chiralities give 80–100% more of thecis form in comparison to the corresponding peptides with the D-Tyr-L-AA-(L-or D-)Phe chiralities. These results indicate that
the incorporation of N-substituted amino acids in small peptides with the same chirality as the precedent amino acid involved
in the peptide bound undergoing thecis/trans isomerisation moves the equilibrium to a significant amount of thecis form. 相似文献
994.
U.M. Csaikl H. Bastian R. Brettschneider S. Gauch A. Meir M. Schauerte F. Scholz C. Sperisen B. Vornam B. Ziegenhagen 《Plant Molecular Biology Reporter》1998,16(1):69-86
Four DNA extraction protocols were compared for ability to produce DNA from the leaves or needles of several species: oak, elm, pine, fir, poplar and maize (fresh materials) and rhododendron (silica dried or frozen material). With the exception of maize and poplar, the species are known to be difficult for DNA extraction. Two protocols represented classical procedures for lysis and purification, and the other two were a combination of classical lysis followed by anion exchange chromatography. The DNA obtained from all procedures was quantified and tested by PCR and Southern hybridisation.Test results indicated superiority of one of the four protocols; a combination of CTAB lysis followed by anion exchange chromatography which enabled DNA extraction from all seven species. A second protocol also produced DNA from leaves or needles of all species investigated and was well suited for PCR applications but not Southern hybridisations. The remaining protocols produced DNA from some but not all species tested.Abbreviations: CTAB, hexadecyltrimethylammonium bromide; EtOH, Ethanol; TBE, tris-borate-EDTA. 相似文献
995.
Charalampos G. Kalodimos Ioannis P. Gerothanassis Anastasios Troganis Bernard Loock Michel Momenteau 《Journal of biomolecular NMR》1998,11(4):423-435
13C NMR spectra of several carbon monoxide (99.7% 13C and 11.8% 18O enriched) hemoprotein models with varying polar and steric effects of the distal organic superstructure and constraints of the proximal side are reported. This enables the 57Fe-13C(O) coupling constants (
), 13C shieldings ((13C)), and 18O isotope effects on13 C shieldings (113C(18O/16O)) to be measured and hence comparisons with hemoproteins, C-O vibrational frequencies and X-ray structural data to be made. Negative polar interactions in the binding pocket and inhibition of Fe//CO back-donation or positive distal polar interactions with amide NH groups appear to have little direct effect on
couplings. Similarly, the axial hindered base 1,2-dimethylimidazole has a minor effect on the
values despite higher rates of CO desorption being observed for such complexes. On the contrary,13 C shieldings vary widely and an excellent correlation was found between the infrared C-O vibrational frequencies ((C-O)) and13 C shieldings and a reasonable correlation with18 O isotope effects on 13C shieldings. This suggests that (13C), (C-O) and1 13 C(18O/16O) are accurate monitors of the multiple mechanisms by which steric and electronic interactions are released in superstructured heme model compounds. The 13C shieldings of heme models cover a 4.0 ppm range which is extended to 7.0 ppm when several HbCO and MbCO species at different pH values are included. The latter were found to obey a similar linear (13 (13C) versus (C-O) relationship, which proves that both heme models and heme proteins are homogeneous from the structural and electronic viewpoint. Our results suggest that (C-O), (13C) and 113C(18O/16O) measurements reflect similar interaction which is primarily the modulation of back-bonding from the Fe d to the CO * orbital by the distal pocket polar interactions. The lack of correlation between1 13 C(18O/16O) and crystallographic CO bond lengths (r(C-O)) reflects significant uncertainties in the X-ray determination of the carbon and oxygen positions. 相似文献
996.
997.
R. Leurs E. Traiffort J. M. Arrang J. Tardivel-Lacombe M. Ruat J.-C. Schwartz 《Journal of neurochemistry》1994,62(2):519-527
Abstract: A cDNA encoding a guinea pig histamine H1 receptor was stably expressed in Chinese hamster ovary (CHO) cells. In one resulting clone, named CHO(H1), the H1 receptor was found to be coupled to several major signal transduction pathways. In each case the involvement of a Gi/Go protein with pertussis toxin (PTX) was assessed, as well as the influence of extracellular Ca2+ and of protein kinase C activation by phorbol 12-myristate 13-acetate (PMA). Histamine induced, in a PTX- and PMA-insensitive manner, a biphasic increase in the intracellular Ca2+ level of which only the second sustained phase was dependent on the extracellular Ca2+ level. Histamine also caused a threefold elevation of inositol phosphate production, which was PTX-insensitive, but slightly inhibited by PMA and reduced by 75% in the absence of extracellular Ca2+. Histamine also caused a massive release of arachidonic acid, which occurred in a Ca2+- and PMA-sensitive manner, probably through the activation of a cytosolic phospholipase A2, which partly involves coupling to a PTX-sensitive G protein. In comparison, in HeLa cells endowed with a native H1 receptor, the histamine-induced arachidonic acid release was also Ca2+- and PMA-sensitive, but totally PTX-insensitive. Finally, in CHO(H1) cells, histamine in very low concentrations potentiated the cyclic AMP accumulation induced by forskolin. This response appeared to be insensitive to PTX, extracellular Ca2+, and PMA. These various observations show that stimulation of a single receptor subtype, the guinea pig H1 receptor, can trigger four major intracellular signals through coupling to several G proteins that are variously modulated by extracellular Ca2+ and protein kinase C activation. 相似文献
998.
Examination of primary metabolic pathways in a murine hybridoma with carbon-13 nuclear magnetic resonance spectroscopy 总被引:3,自引:0,他引:3
Mancuso A Sharfstein ST Tucker SN Clark DS Blanch HW 《Biotechnology and bioengineering》1994,44(5):563-585
Primary metabolism of a murine hybridoma was probed with (13)C nuclear magnetic resonance (NMR) spectroscopy. Cells cultured in a hollow fiber bioreactor were serially infused with [1-(13)C] glucose, [2-(13)C] glucose, and [3-(13)C] glutamine. In vivo spectroscopy of the culture was used in conjunction with off-line spectroscopy of the medium to determine the intracellular concentration of several metabolic intermediates and to determine fluxes for primary metabolic pathways. Intracellular concentrations of pyruvate and alanine were very high relative to levels observed in normal quiescent mammalian cells. Estimates made from labeling patterns in lactate indicate that 76% of pyruvate is derived directly from glycolysis; some is also derived from the malate shunt, the pyruvate/melate shuttle associated with lipid synthesis and the pentose phosphate pathway. The rate of formation of pyruvate from the pentose phosphate pathway was estimated to be 4% of that from glycolysis; This value is a lower limit and the actual value may be higher. Incorporation of pyruvate into the tricarboxylic acid (TCA) cycle appears to occur through only pyruvate dehydrogenase; no pyruvate carboxylase activity was detected. The malate shunt rate was approximately equal to the rate of glutamine uptake. The rate of incorporation of glucosederived acetyl-CoA into lipids was 4% of the glucose uptake rate. The TCA cycle rate between isocitrate and alpha-ketoglutarate was 110% of the glutamine uptake rate. (c) 1994 John Wiley & Sons, Inc. 相似文献
999.
为探究黄淮冬麦区测墒补灌节水条件下协同提高小麦产量和水氮利用效率的氮肥管理措施,以小麦品种‘烟农1212'为材料,在拔节期和开花期将各处理0~40 cm土层土壤相对含水量均补灌至70%条件下,设置3个施氮水平,即150(N1)、210(N2)和270 kg·hm-2(黄淮冬麦区常规施氮量,N3),研究施氮量对小麦开花后旗叶光合特性、13C同化物积累与转运及水氮利用效率的影响。结果表明: N2和N3处理开花后14~35 d旗叶光合能力显著高于N1处理,N2与N3处理间差异不显著。13C同位素示踪结果显示,N2处理开花后营养器官13C同化物转运量比N1和N3处理分别高12.1%和7.1%,成熟期13C同化物在籽粒中的分配量比N1和N3处理分别高10.1%和5.3%。施氮量亦调节了小麦不同生育阶段的耗水量、耗水模系数和总耗水量,小麦全生育期耗水量表现为N2与N3处理无显著差异,但均显著高于N1处理,N2处理拔节至成熟期阶段耗水量和耗水模系数均较高。N2处理水分利用效率比N3和N1处理分别高7.5%和4.8%,籽粒产量比N3和N1处理分别高4.7%和10.9%,氮肥偏生产力比N3处理高34.6%。综合考虑小麦籽粒产量和水氮利用效率,施氮量为210 kg·hm-2处理为研究区测墒补灌节水条件下的最佳施氮量。 相似文献
1000.