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81.
将菠菜叶片匀浆后.用差速离心和梯度率心分离叶绿体、过氧物酶体、微粒体等细胞器和100000×g上清法部分。用酶活测定法测定各部分甜菜碱醛脱氢酶(BADH)的活性;用免疫扩散法鉴定各组分的BADH。除叶绿体外,过氧物酶体、微粒体.以及100000×g上清液中也存在BADH。 相似文献
82.
The ability of neurotrophin-4/5 (NT-4/5), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and nerve growth factor (NGF) to promote survival of postnatal rat vestibular ganglion neurons (VGNs) was examined in dissociated cell cultures. Of the four neurotrophins, NT-4/5 and BDNF were equally effective but more potent than NT-3 in promoting the survival of VGNs. In contrast, NGF showed no detectable effects. As expected, TrkB-IgG (a fusion protein of extracellular domain of TrkB and Fc domain of human immunoglobulin G) specifically inhibited the survival-promoting effects by NT-4/5 or BDNF and TrkC-IgG fusion protein completely blocked that of NT-3. Immunohistochemistry with TrkB, TrkA, and p75 antisera revealed that VGNs made TrkB and p75 proteins, but not TrkA protein. Ototoxic therapeutic drugs such as cisplatin and gentamicin often induce degeneration of hair cells and ganglion neurons in both auditory and vestibular systems that leads to impairment of hearing and balance. When cisplatin and gentamicin were added to the dissociated VGN culture in which the hair cells were absent, additional cell death of VGNs was induced, suggesting that the two ototoxins may have a direct neurotoxic effect on ganglion neurons in addition to their known toxicity on hair cells. However, if the cultures were co-treated with neurotrophins, NT-4/5, BDNF, and NT-3, but not NGF, prevented or reduced the neurotoxicity of the two ototoxins. Thus, the three neurotrophins are survival factors for VGNs and are implicated in the therapeutic prevention of VGN loss caused by injury and ototoxins. © 1995 John Wiley & Sons, Inc. 相似文献
83.
华南胡椒化学成分的研究 总被引:1,自引:0,他引:1
从胡椒科植物华南胡椒(Piper austrosinense C.DC.)中分离出七个成分,经光谱分析和理化常数测定,分别鉴定为N-isobutyl-3(3',4'-methylenedioxy-5'-methoxyphenyl)-2E-trimonoienamide(I)、N-isobutyl-7(3',4'-metylenedioxyphenyl)-2E,4E-heptadienamide(Ⅱ 相似文献
84.
85.
寡糖素对红花及三七培养细胞的生理作用 总被引:5,自引:0,他引:5
三种寡糖素,即来自人参(Panax ginseng)培养细胞的人参寡糖素、红花(Carthamus tinctorius)培养细胞的红花寡糖素、黑节草(Dendrobium candidum)植物的黑节草寡糖素对红花及三七(Panax notoginseng)的培养细胞的生长及代谢产物的含量均有显著的促进作用。寡糖素可耐高温高压(121℃、.bs/cm^2)灭菌15分钟而不失活,其对植物培养细胞的 相似文献
86.
酪氨酸羟化酶基因载体-pCMVTH 质粒的构建及在大鼠骨骼肌内的表达 总被引:4,自引:0,他引:4
为用转基因方法治疗巴金森氏病大鼠模型,本研究采用分子克隆技术,将合成多巴胺的关键酶-酪氨酸羟化酶(TH)的基因,克隆进入以巨细胞病毒CMV为启动子的载体质粒内,经限制性内切酶定位分析证实该重组的DNA质粒的可靠性。携带TH基因的PCMVTH质粒以LIPO-FECTIN介导,在培养的原代骨骼肌细胞中高效表达。本研究为进一步用转基因的细胞植入脑内以治疗巴金森氏病打下一定基础。 相似文献
87.
对79名HBV标志阴性少年人群,以乙肝疫苗10μg×3的免疫剂量和0、1、2月的免疫程序进行接种,对其抗-HBs免疫应答和临床保护效果作了为期7年的定人随访。结果表明,抗-HBs阳转率在免后三个月时为100%,均值为3084MIU/ml。至免后84个月时疫苗接受者中仍有55.7%的抗-HBs水平≥10MIU/ml。6例检出抗-HBs,其中5例的抗-HBs持续处于高水平。全部观察对象无一例检出HBsAg或发生临床肝炎。少年接种乙肝血源疫苗至少7年内可具有保护性抗体。故在此期内不需加强免疫。 相似文献
88.
野生紫斑牡丹和四川牡丹种子萌发特性及与其致濒的关系 总被引:6,自引:0,他引:6
野生牡丹种子一般较小,而且不同产地之间形状、大小差异较大。其萌发特性与栽培牡丹相比也有较大差异:萌发期长达半年以上,且萌发温度在10~15℃为宜,超过20℃则明显不利于生根及上胚轴生长。四个不同分布地的四川牡丹种子萌发率较一致,均在60~77%之间。三个不同产地的紫斑牡丹种子萌发率则相差甚远,分布于甘肃文县的萌发率达76%,而分布于陕西略阳和湖北神农架的萌发率则分别只有12%和4.4%,出苗率则更低。本文认为紫斑牡丹的种子特性是其在自然界处于濒危状态的重要原因之一。 相似文献
89.
Activation of MEK family kinases requires phosphorylation of two conserved Ser/Thr residues. 总被引:30,自引:7,他引:23 下载免费PDF全文
MEK is a family of dual specific protein kinases which activate the extracellular signal-regulated kinases by phosphorylation of threonine and tyrosine residues. MEK itself is activated via serine phosphorylation by upstream activator kinases, including c-raf, mos and MEK kinase. Here, we report the activation phosphorylation sites of human MEK1 and yeast STE7 kinase as determined by a combination of biochemical and genetic approaches. In human MEK1, substitution of either serine residue 218 or 222 with alanine completely abolished its activation by epidermal growth factor-stimulated Swiss 3T3 cell lysates or immunoprecipitated c-raf, suggesting that both serine residues are required for MEK1 activation. Phosphopeptide analysis demonstrated that serine residues 218 and 222 of human MEK1 are the primary sites for phosphorylation by c-raf. These two serine residues are highly conserved in all members of the MEK family, including the yeast STE7 gene product, a MEK homolog in the yeast mating pheromone response pathway. Mutation of the corresponding residues in STE7 completely abolished the biological functions of this gene. These data demonstrate that MEK is activated by phosphorylation of two adjacent serine/threonine residues and this activation mechanism is conserved in the MEK family kinases. 相似文献
90.
Simultaneous extraction of soil phytoavailable cadmium,copper, and lead by chelating resin membrane 总被引:2,自引:0,他引:2
Cadmium, copper, and lead were extracted from suspensions of contaminated soils using metal chelating exchange resin membranes.
Nine soils with widely varying properties and Cd, Cu and Pb levels were tested. Soil suspensions made up with 4 g in 40 mL
deionized water were equilibrated with 5 cm2 Ca-saturated Chelex exchange resin membrane which was retained inside a polypropylene bag and shaken at 150 rpm for 24 hrs.
Resin membrane extractable Cd, Cu and Pb of the soils were correlated with Cd, Cu, and Pb uptake by young wheat seedlings
grown in these soils and compared with soil Cd, Cu, and Pb extracted by 0.1 M HCl, 0.01 M CaCl2, and 0.005 M Diethylenetriamine pentaacetic acid (DTPA). The amounts of Cd, Cu and Pb extracted by the Ca-saturated Chelex membrane from
all tested soils correlated well with those absorbed by young wheat seedlings. The Ca-saturated Chelex membrane extractable
Cd, Cu and Pb of the soil had the strongest correlation with plant uptake Cd, Cu and Pb among the extraction methods we tested.
It was demonstrated that the Ca-saturated Chelex membrane extraction is an appropriate method in simultaneously estimating
Cd, Cu and Pb phytoavailability of soil and is applicable to a wide range of soils. 相似文献