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101.
阿尔金山地区的奥陶系分布于索尔库里和色什考贡的断块中,首先为新疆区调队发现。1979年,该队在索尔库里以北金鸿山西北乱石山东南7km处(东经90°59′;北纬39°)测制了奥陶系剖面,自上而下,划分出环形山组、乱石山组和亚普恰萨依组,顶部出露不全,底部平行不整合覆于震旦纪大理岩之上。两个地点的腕足类化石经刘第墉等(1984,156页)研究,认为其时代应主要归于Llandeilian。索尔库里的环形山组厚约414m,上部为深灰色薄层灰岩,下部是深灰色薄层灰岩夹少量细砂岩,产腕足类、笔石和三叶虫化石。从所产三叶虫化石(790H_2-XV-26)Xinjianjia tari 相似文献
102.
Translucent Tissue Defects in Solanum tuberosum L. : II. Alterations in Lipolytic Acyl Hydrolase, Lipoxygenase, and Morphology of Mitochondria and Amyloplasts
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We analyzed a physiological defect that involved translucent-like tissue which occurred randomly in potato tubers (Solanum tuberosum L., cv Kennebec) after 8 months of storage. The translucent areas had reduced lipoxygenase (0.73-fold) and lipolytic acyl hydrolase (0.27-fold) activities. The effect(s) of these reduced enzyme activities in vivo is uncertain, but they may have influenced composition, turnover and permeability of membranes because potato lipid is primarily membranous in nature. Electron micrographs of the translucent tissue revealed a discernible decrease in the number of starch granules compared to normal/healthy tissue. A few remaining amyloplasts, which still contained starch granules, possessed large electrondense areas (stroma) within the organelle. Mitochondria in translucent tissue appeared to be present in increased numbers, were aggregated, had fewer but swollen cristae, and, morphologically, were of irregular size and shape suggestive of division. The result of this tuber defect appeared, in part, to be an exaggerated or accelerated form of senescence. 相似文献
103.
Stomatal diffusion resistance in primary leaves of Phaseolus vulgaris L. which had been grown in light:dark cycles followed a marked circadian rhythm when the plants were transferred to continuous darkness. Reentrainment of the rhythm required more than one inductive change in photoperiod. The phasing of the rhythm of dark stomatal opening was contolled primarily by the light-on (dawn) signal, whereas the rhythm of dark closure was related to the light-off (dusk) signal. The evidence points to a dual control of the circadian clock in which a product of photosynthesis plays a major role. No evidence for phytochrome involvement in the phasing of the rhythm was found. An influence of phytochrome on the amplitude of the stomatal rhythm was observed in which removal of phytochrome-far-red absorbing form caused rapid damping. 相似文献
104.
Differential Proteolysis of Glycinin and beta-Conglycinin Polypeptides during Soybean Germination and Seedling Growth 总被引:1,自引:0,他引:1
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The degradation of the major seed storage globulins of the soybean (Glycine max [L.] Merrill) was examined during the first 12 days of germination and seedling growth. The appearance of glycinin and β-conglycinin degradation products was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cotyledon extracts followed by electroblotting to nitrocellulose and immunostaining using glycinin and β-conglycinin specific antibodies. The three subunits of β-conglycinin were preferentially metabolized. Of the three subunits of β-conglycinin, the larger α and α′ subunits are rapidly degraded, generating new β-conglycinin cross-reactive polypeptides of 51,200 molecular weight soon after imbibition of the seed. After 6 days of growth the β-subunit is also hydrolyzed. At least six polypeptides, ranging from 33,100 to 24,000 molecular weight, appear as apparent degradation products of β-conglycinin. The metabolism of the glycinin acidic chains begins early in growth. The glycinin acidic chains present at day 3 have already been altered from the native form in the ungerminated seed, as evidenced by their higher mobility in an alkaline-urea polyacrylamide gel electrophoresis system. However, no change in the molecular weight of these chains is detectable by sodium dodecyl sulfate-polyarylamide gel electrophoresis. Examination of the glycinin polypeptide amino-termini by dansylation suggests that this initial modification of the acidic chains involves limited proteolysis at the carboxyl-termini, deamidation, or both. After 3 days of growth the acidic chains are rapidly hydrolyzed to a smaller (21,900 molecular weight) form. The basic polypeptides of glycinin appear to be unaltered during the first 8 days of growth, but are rapidly degraded thereafter to unidentified products. All of the original glycinin basic chains have been destroyed by day 10 of growth. 相似文献
105.
选取黄瓜小孢子单核期的花药以组织培养方法检验铁氰化钾的杀雄效应,并初步探讨该试剂的杀雄机理。实验表明,该试剂在组织培养条件下,使用的浓度范围为0.1—10ppm 时,均显示有杀雄效应。表现为:处理的花药发育缓慢,小孢子变形或外粉壁不能形成。同时处理雌花则作用不明显。通过细胞形态观察,过氧化物酶、核酸、蛋白质及多糖组化定位及花粉壁的扫描电镜观察,初步认为:该试剂的杀雄效应与绒毡层、小孢子的过氧化物酶活性受抑制有关,故为生理性不育。 相似文献
106.
107.
使用5-溴脱氧尿嘧啶核苷(Brdu),对鸡胚神经视纲膜的形态发生与生化分化进行研究,以探讨基因的调节作用。 发育六天的鸡胚视纲膜经Brdu短期培养后,形态发生不可逆地抑制。但Brdu对发育七天的视纲膜的抑制作用是可逆的,发育九天的鸡胚视纲膜却不受其影响。 从发育六、七、九天的鸡胚视纲膜中提取DNA,进行CD谱的研究,与对照相比,经Brdu处理的视纲膜DNA的CD谱发生兰移,而且在260—280nm及290—300nm区域的吸收强度发生改变。Brdu还使发育六、七天的视纲膜染色质的CD谱发生明显变化,但发育九天的视纲膜染色质的CD谱的变化则不明显。对经Brdu作用的视纲膜DNA和染色质进行热稳定性分析结果也说明发育六、七、九天的视纲膜DNA的值和增色效应都有所增加,而染色质热稳定性的变化却不完全一致。 相似文献
108.
听阈测定是电反应测听术的主要检查项目,目前耳科临床以脑干电位为最常用的指标。叠加平均技术的应用使反映听觉系统各水平活动的声音诱发电位都可从体表记录到。究竟哪一种电位对听阈的测定最为灵敏和方便,这是电反应测听术应用中的一个较基本的问题。豚鼠是听觉研究的常用动物,在清醒豚鼠较易记录各种听觉诱发电位并对其反应阈进行对比。本工作报导一些对比结果。 相似文献
109.
110.