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991.
992.
Low density lipoprotein receptor-related protein mediates apolipoprotein E inhibition of smooth muscle cell migration. 总被引:5,自引:0,他引:5
This research was undertaken to identify the cell surface receptor responsible for mediating apolipoprotein E (apoE) inhibition of platelet-derived growth factor (PDGF)-directed smooth muscle cell migration. Initial studies revealed the expression of the low density lipoprotein receptor (LDLR), the LDL receptor-related protein (LRP), the very low density lipoprotein receptor (VLDL), and apoE receptor-2 in mouse aortic smooth muscle cells. Smooth muscle cells isolated from LDLR-null, VLDL-null, and apoE receptor-2-null mice were responsive to apoE inhibition of PDGF-directed smooth muscle cell migration, suggesting that these receptors were not involved. An antisense RNA expression knockdown strategy, utilizing morpholino antisense RNA against LRP, was used to reduce LRP expression in smooth muscle cells to assess the role of this receptor in apoE inhibition of cell migration. Results showed that apoE was unable to inhibit PDGF-directed migration of LRP-deficient smooth muscle cells. The role of LRP in mediating apoE inhibition of PDGF-directed smooth muscle cell migration was confirmed by experiments showing that antibodies against LRP effectively suppressed apoE inhibition of PDGF-directed smooth muscle cell migration. Taken together, these results document that apoE binding to LRP is required for its inhibition of PDGF-directed smooth muscle cell migration. 相似文献
993.
Zhi-Dong Xu He Liu Su-Long Xiao Ming Yang Xian-He Bu 《Journal of inorganic biochemistry》2002,90(3-4)
The complex [Mn(L)(NO3)2(H2O)2] (1) (L=2H-5-hydroxy-1,2,5-oxadiazo[3,4-f]1,10-phenanthroline) was synthesized and characterized by elemental analysis, IR and UV. The crystal and molecular structure of 1 was determined by single-crystal X-ray diffraction; crystal data: light yellow, monoclinic, space group P21/n, Z=4, a=7.432(2) Å, b=9.582(3) Å, c=23.445(7) Å, β=90.519(5)°. The Mn atom in 1 is hexa-coordinated in a distorted octahedral arrangement by two N atoms of the ligand L and four O atoms of two water molecules and two nitrate anions. Biological tests in vitro showed that 1 has significant antitumor activity against HL-60, KB, Hela and BGC-823 cells. The interaction of 1 with calf thymus DNA was investigated by absorption titration, thermal denaturation and viscosity measurements. The results suggest that 1 binds with DNA by intercalating via the ligand L. 相似文献
994.
棉蚜乙酰胆碱受体亚基的选择性剪接和多重转录起始位点分析 总被引:4,自引:0,他引:4
乙酰胆碱受体在神经突触传导过程中具有重要作用,也是氯化胆碱类杀虫剂的作用靶标。采用RACE技术,成功地从棉蚜中克隆了3个nAChR亚基,其中2个为α亚型, 1个为β亚型,分别命名为Agα1、Agα2和Agβ1。通过锚定mRNA的5′mG结构, 5′RACE结果表明Agβ1有三个不同的剪接变体,具有不同长度的5′UTR区,表明Agβ1亚基具有多重的转录起始位点。其中,最短的剪接变体Agβ1C在蛋白编码区域也存在选择性剪接,位于D环区域的186 bp碱基缺失。3′RACE实验结果表明,Agα1亚基虽然具有ploy ( A)和加尾信号AATAAA等完整的mRNA基因结构,但缺失了终止子和乙酰胆碱受体α亚基保守的第4个跨膜区,文中对此做了进一步分析。分子进化树的分析表明,昆虫乙酰胆碱受体亚基应当被划分为三个不同的亚类群αⅠ,αⅡandβ。本文的研究揭示了昆虫乙酰胆碱受体亚基复杂的基因结构[动物学报51 (5) : 867 -878 , 2005]。 相似文献
995.
福氏2a志贺氏菌2457T HtpG蛋白诱导小鼠炎性反应 总被引:1,自引:0,他引:1
[目的]构建福氏2a志贺氏菌2457T株的htpG缺失突变株和回复株,对HtpG蛋白的功能进行初步研究.[方法]采用X-Red重组系统对htpG基因进行缺失突变,构建了福氏2a志贺氏菌2457T株的htpG缺失突变株,并利用低拷贝质粒构建了htpG突变株的回复株.在此基础上,对野生株、突变株和回复株的生长曲线、生化反应、豚鼠角膜试验进行了比较分析,并考察了野生株、突变株和回复株腹腔注射引起小鼠炎症反应的强弱.[结果]HtpG蛋白功能与福氏志贺氏菌的基本生化代谢无关,也不影响细菌穿透上皮细胞的能力,但腹腔注射后能够引起小鼠强烈的炎症反应.[结论]HtpG蛋白功能可能与细菌的免疫致病性相关. 相似文献
996.
997.
Compared to agricultural land and spruce plantations, central European beech-oak forests are often relatively close to natural
conditions. However, forest management may alter these conditions. In Steigerwald, southern Germany, a large beech-dominated
forest area, three management intensities were applied during the past 30–70 years. Here, we examined the influence of management
intensity on saproxylic beetles in >100-year old mature stands at 69 sampling plots in 2004. We sampled beetles using flight-window
traps and time standard direct searches. The community structure based on presence/absence data changed remarkably along the
gradient from unmanaged to low-intensity to high-intensity management, but these differences were not evident using abundance
data from flight interception traps. Saproxylic species richness decreased in intensively managed forests. Elateridae and
threatened species richness peaked in unmanaged forests and in forests under low-intensity management. Saproxylic species
richness was dependent on certain micro-habitat factors. These factors were (1) the amount of dead wood for Elateridae, overall
and threatened saproxylic beetle richness; (2) the amount of flowering plants for Cerambycidae; (3) the richness of wood-inhabiting
fungi for Staphylinidae, Melandryidae and overall saproxylic beetle richness; and (4) the frequency of Fomes fomentarius for threatened species. Species richness was better explained by plot factors, such as dead wood or fungi, than by management
intensity. These results suggest that the natural variation of dead wood niches (decay stages, snag sizes, tree cavities and
wood-inhabiting fungi species) must be maintained to efficiently conserve the whole saproxylic beetle fauna of beech forests.
Also, intensive management may alter the specialised saproxylic beetle community even if the initial tree-species composition
is maintained, which was the case in our study. For monitoring the ecological sustainability of forest management we must
focus on threatened species. If structures alone are sampled then the amount of dead wood is the best indicator for a rich
saproxylic beetle fauna. 相似文献
998.
999.
1000.
Sergeant N Bretteville A Hamdane M Caillet-Boudin ML Grognet P Bombois S Blum D Delacourte A Pasquier F Vanmechelen E Schraen-Maschke S Buée L 《Expert review of proteomics》2008,5(2):207-224
Microtubule-associated Tau proteins belong to a family of factors that polymerize tubulin dimers and stabilize microtubules. Tau is strongly expressed in neurons, localized in the axon and is essential for neuronal plasticity and network. From the very beginning of Tau discovery, proteomics methods have been essential to the knowledge of Tau biochemistry and biology. In this review, we have summarized the main contributions of several proteomic methods in the understanding of Tau, including expression, post-translational modifications and structure, in both physiological and pathophysiological aspects. Finally, recent advances in proteomics technology are essential to develop further therapeutic targets and early predictive and discriminative diagnostic assays for Alzheimer's disease and related disorders. 相似文献