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排序方式: 共有1117条查询结果,搜索用时 15 毫秒
941.
Supercapacitor (SC) is one of the most promising electrochemical energy-storage devices. However, the practical application of SCs is limited by the low-energy density. Herein, high-temperature shock (HTS)-derived ultrafine structure-activated porous carbon (UAPC) with N, O functional groups is reported as high-energy density SCs carbon. The process of ultrafast joule heating and cooling effectively transfers general-purposed carbon into electrochemical-activated carbon. The UAPC-based SCs exhibit an energy density of up to 129 Wh kg−1 in EMIMBF4 ionic liquid, which outperform almost all reported and commercial SCs (22 Wh kg−1). The outstanding electrochemical performance of UAPC is attributed to the ultrafine structure and N, O functional groups, which enlarges the surface area, improves the surface wettability of UAPC electrodes, and provides pseudocapacitance. The facile and efficient ultrafast-processing strategy has opened up an unprecedented pathway for the application of low-value carbon for the electrode design and application of SCs.  相似文献   
942.
利用三亲本接合转移方法,将快生型大豆根病菌B_(52)的基因文库克隆转移到受体菌慢生型大豆根瘤菌2210中,获得4株大豆基因工程根瘤菌(32.43、B—2—6、B—3—8)。田间接种试验表明:在大豆分枝期(V2),43和32结瘤效分别比不接种对照增加117.9%和100.4%;在初花期(R_1),32和B—2—6结瘤数分别比对照增加122.5%和91.6%,根瘤固氮酶活性增加233.3%和195.6%;在结荚始期(R3),B—2—6和32结瘤数比对照增加78.5%和70.1%,根瘤固氟酶活性43和B—2—6分别比对照增加53.4%和49.3%。产量统计表明:32、B—2—6和43比对照分别增产16.8%、14.3%和12.2%,亩增收大豆分别为28.2、24.1和20.6公斤。以上三个菌株均比受体菌株2210增产率高。  相似文献   
943.
Deoxyhypusine formation on the 18 kDa eIF-4D precursor is due to a covalent linkage between a lysine residue of the protein and the aminobutyl moiety derived from spermidine. The deoxyhypusine is then hydroxylated to form hypusine. This post-translational modification represents one of the most specific spermidine-dependent biochemical events in eukaryotic cells. Deoxyhypusine formation can be performed in vitro at pH 9.5 and is greatly stimulated by NAD+. Using the labeling of the 18 kDa protein by [3H]spermidine as an assay for deoxyhypusine formation, we found that (i) significant deoxyhypusine formation can be demonstrated in vitro at pH 7.2 only if NAD+ is present, (ii) deoxyhypusine formation was sensitive to buffer composition; buffers made of basic amino acids and Tris were inhibitory, (iii) sulfhydryl reagents and metal ions such as Cu2+ and Fe3+ were potent inhibitors of deoxyhypusine formation and (iv) the 18 kDa protein substrate was heat-stable. The in vitro activity of deoxyhypusine formation, which depends on the presence of both enzyme and protein substrate, can be separated from the product, eIF-4D, by a one-step Cibacron blue dye affinity column. Taking advantage of this finding, we have developed a simple procedure, based on the use of Cibacron blue dye, for partially purifying both the deoxyhypusine-forming enzyme and the 18 kDa protein substrate. When the partially purified enzyme and protein substrate were mixed in the presence of 1 mM NAD+ and [3H]spermidine, the 18 kDa protein was radiolabeled, no labeling could be detected if any one component was absent. Using partially purified enzyme, we have also determined the half-life of the protein substrate in alpha-difluoromethyl ornithine (DFMO)-treated NB-15 cells and found it to be longer than 10 h.  相似文献   
944.
为揭示遗传改良对主要造林用材树种叶和种实性状的影响,阐明性状的变异趋势,该研究以杉木第4轮育种的精选树(改良群体)、四省五地的表型优树与古树(未改良群体)为对象,调查了218个无性系的针叶和种实性状指标,采用方差分析和多重对比方法研究遗传改良对杉木及不同类型杉木的表型差异,并通过相关性分析探究遗传改良对杉木针叶和球果部分表型性状的影响,以及利用主成分分析和聚类分析进行了分类。结果表明:(1)未改良群体的针叶长、针叶宽和出籽率分别比改良群体小13.28%、10.81%和33.90%,其他性状表现为未改良群体大于改良群体,差异在10.90%~27.03%之间。未改良群体球果长、球果宽和出籽率的变异系数,分别比改良群体大9.14%、12.73%和15.38%。(2)球果长、球果宽、苞鳞长和苞鳞宽4个性状,在未改良群体中仅有球果长和球果宽(0.931)、苞鳞长和苞鳞宽(0.622)之间呈极显著正相关,经遗传改良后,该4个性状两两之间均呈显著或极显著正相关。(3)四川雅安(SCYA)的球果长和球果宽的性状比改良群体大48.83%和53.26%,安徽黄山(AHHS)的百粒重比改良群体大16.92%。(4)遗传改良导致松张型球果的杉木比例降低,紧包型和反翘型球果的杉木比例增加。综上认为,杉木的遗传改良导致球果大小下降,改变了不同针叶和球果类型的比例,同时会改变针叶性状和种实性状的相关性,将为杉木种质资源评价和未来多目标育种提供依据。  相似文献   
945.
<正>Dear Editor,The peste des petits ruminants virus(PPRV)causes an increasingly important viral disease of livestock that predominantly infects small ruminants such as goats and sheep.It belongs to the Paramyxoviridae family and is classified as the fourth member of the genus Morbillivirus because of its genetic similarity with other members of this genus,which includes measles virus(MV),rinderpest virus(RPV),canine distemper virus  相似文献   
946.
免疫外科法分离克隆BALB/c小鼠胚胎干细胞   总被引:8,自引:0,他引:8  
目的 使用免疫外科法分离克隆BALB c小鼠胚胎干细胞 (embryonicstemcells,ES细胞 ) ,为进一步建立BALB c小鼠ES细胞系打下基础。方法 用免疫外科法从 4 5枚BALB c小鼠囊胚中分离得到 2 0枚去除滋养层细胞的ICM ,接种在MEF饲养层上 ,使用DMEM(高糖 ) 15 ?S 0 1mmol Lβ 巯基乙醇 0 0 1mmol L非必需氨基酸 10 0 0IU mlLIF 10 0IU mL青霉素 10 0IU ml链霉素培养液 ,17枚形成典型的ICM集落 (85 0 % ) ,有一枚胚胎传至第 10代。用于全胚培养的BALB c小鼠胚胎共 10 2枚 ,使用与免疫外科相同的培养方法 ,6 6枚形成典型的ICM集落 (6 4 7% ) ,其中一枚胚胎传至第 8代。结果 免疫外科法较全胚培养法有利于小鼠ES细胞的分离与克隆 ;添加LIF(10 0 0IU ml)有利于小鼠ES细胞的分离与传代 (P <0 0 5 ) ;0 0 5 %胰酶 0 0 0 8?TA是较好的ES细胞消化液 ,对细胞综合损伤力小 ,且传代后ES细胞集落形成能力也较高 (P <0 0 5 )。结论 分离得到的ES细胞经形态学观察 ,AKP染色 ,体外分化实验 ,核型分析等证明其具有胚胎干细胞的诸多特性。  相似文献   
947.
The west Jilin Province is a typical area in the ecotone between agriculture and animal husbandry, with a frangible eco-environment. With respect to the three aspects of water resource, natural disasters and land degradation, 10 indices were selected to establish a mat-ter-element model for the assessment of eco-envir-onmental frangibility in the west Jilin Province. The results indicate that during 1985-2000, Qian'an, Fuyu, and Changling had the least frangibility (level I), followed by Da'an and Qianguo (level II), and Taobei, Zhenlai, Taonan, and Tongyu had the highest frangibility (level III). On the whole, the counties in Songyuan city were less frangible than those in Baicheng city. Different counties had different frangibilities to environmental factors, e.g., Da'an and Tongyu were frangible in water resource con-ditions; Taobei, Zhenlai, Taonan, Tongyu and Qian'an suffered most from natural disasters; while Taobei, Taonan and Qianguo were threatened by severe land degradation.  相似文献   
948.
949.
950.
Glucagon-like peptide-1 (GLP-1) is a 30-residue peptide hormone secreted by intestinal L-cells in response to nutrient ingestion. In the present study, overlapping PCR technology was employed to construct two GLP-1 mutants (GLP-1(A2G))2 and human albumin (HSA) genes in vitro without linker. The spliced gene, (GLP-1(A2G))2-HSA, was over expressed under the control of promoter AOX1 and Mat alpha signal peptide in Pichia pastoris. SDS-PAGE and Western blotting were applied to assay the recombinant fusion protein in the culture broth. The results demonstrated that the recombinant (GLP-1(A2G))2-HSA concentration in the broth could reach a level of 245.0 mg/L and the expressed fusion protein was capable of cross-reacting with anti-human GLP-1 and anti-human albumin antibody. The recombinant (GLP-1(A2G))2-HSA protein was purified by ultrafiltration, columns of Q-sepharose fast flow and Superdex 75 size-exclusion. The recombinant (GLP-1(A2G))2-HSA protein obtained could lower in vivo glucose concentration in blood and stimulate in vitro islet cell proliferation. In mouse model, the fusion protein was detectable in plasma even 308 h after a single subcutaneous dose of 1.25 mg/kg. The result showed that the terminal biological half-time of the protein was about 54.2 h which is 650-fold longer than that of GLP-1. The pharmacokinetic analysis of the protein suggests its promising application in clinical medicine.  相似文献   
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