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121.
超氧化物歧化酶模拟化合物的生物活性研究 总被引:16,自引:0,他引:16
根据天然超氧化物歧化酶(SOD)活性部位结构合成了含苯并咪唑的5种配体及其32种分别含Cu(Ⅱ)、Fe(Ⅲ)、Mn(Ⅱ)、Co(Ⅱ)的模拟化合物.经光谱、电化学测试证明这些化合物具有拟S3D活性,其50%抑制率浓度(IC50)为10-6~10-8mol·L-1,催化超氧离子自由基(O-·2)歧化的反应速率常数kq为106~108mol-1·L·s-1.同时观察到几种模拟化合物有抗肿瘤活性或增强水稻抗寒性. 相似文献
122.
为克隆肺腺癌分化相关基因, 采用诱导分化与消减杂交相结合的策略, 建立了全反式维甲酸(RA)诱导前后人肺腺癌细胞系的cDNA消减文库, 得到124个cDNA消减克隆. 经加减法杂交差异筛选、DNA和RNA印迹、cDNA全序列测定和生物学功能分析, 分离到3个在人肺腺癌细胞系分化过程中由RA激活而特异表达的新的cDNA序列这一策略和技术路线适用于分离细胞中呈过量表达或表达抑制基因的cDNA克隆, 并具有反映细胞分化过程中基因表达动态变化特征和相对简便适用的特点. 相似文献
123.
检测香蕉花叶心腐病病原CMV的PAS—ELISA方法的改进 总被引:1,自引:0,他引:1
作为一种快速、敏感的免疫学方法,ELISA已被广泛地用于植物病毒的研究与应用性检测方面。在实验室中用PAS-ELISA检测香蕉花叶心腐病病原CMV已被证明是一种获得无CMV组培苗的有效手段。在香蕉无病毒组培苗工厂化大批量生产中,我们应用此法作为质量控制的手段之一,剔除病苗,保证产品不带CMV,获得一定成效。但同时我们也发现,香蕉组织中含有引起非特异性吸附反应的物 相似文献
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建立了测定人乳腺癌胞浆cAMP结合蛋白(cAMPb.p.)方法。综合研究了其温度、保温时间、配体浓度、稳定性等条件。cAMPb.p.的K_D值为2.90×10~(-8)mol/L.并测定了60例雌激素受体(ER)Fu性乳腺癌标本的cAMPb.p.含量。此组病人术后均接受系统的内分泌治疗,ER/cAMPbp,比值范围为7.7~362×10~(-3),ER/cAMPb.p.比值≥40×10~(-3)的五年生存率明显高于比值<40×10~(-3)组,(p<0.005).表明测定ER/cAMPb.p.比值对预测患者内分泌治疗疗效,优于单独测定ER. 相似文献
128.
Characterization of a Chlamydomonas reinhardtii gene encoding a protein of the DNA photolyase/blue light photoreceptor family 总被引:6,自引:0,他引:6
The organization and nucleotide sequence of a gene from Chlamydomonas reinhardtii encoding a member of the DNA photolyase/blue light photoreceptor protein family is reported. A region of over 7 kb encompassing the gene was sequenced. Northern analysis detected a single 4.2 kb mRNA. The gene consists of eight exons and seven introns, and encodes a predicted protein of 867 amino acids. The first 500 amino acids exhibit significant homology with previously sequenced DNA photolyases, showing the closest relationship to mustard (Sinapis alba) photolyase (43% identity). An even higher identity, 49%, is obtained when the Chlamydomonas gene product is compared to the putative blue-light photoreceptor (HY4) from Arabidopsis thaliana. Both the Chlamydomonas and the Arabidopsis proteins differ from the well characterized DNA photolyases in that they contain a carboxyl terminal extension of 367 and 181 amino acids, respectively. However, there is very little homology between the carboxyl terminal domains of the two proteins. A previously isolated Chlamydomonas mutant, phrl, which is deficient in DNA photolyase activity, especially in the nucleus, was shown by RFLP analysis not to be linked to the gene we have isolated. We propose this gene encodes a candidate Chlamydomonas blue light photoreceptor. 相似文献
129.
Yoshiaki Nose Jae Min Lee Takatoshi Ueno Masatsugu Hatakeyama Kugao Oishi 《Insect biochemistry and molecular biology》1997,27(12):1047-1056
The cDNA for vitellogenin (Vg) of the parasitoid wasp Pimpla nipponica (Hymenoptera: Apocrita) was cloned and sequenced.1 The deduced amino acid sequence with 1807 residues was obtained. The N-terminal 20 amino acids chemically determined for vitellin (Vn) agreed completely with the deduced 20 amino acids that follow the 16 amino acid residues for putative signal peptide. The cDNA clone for the Vg of the turnip sawfly Athalia rosae (Hymenoptera: Symphyta), previously obtained and partially sequenced, was also completely sequenced and the amino acid sequence deduced. Amino acid sequences were compared between these two species and also with known Vg sequences from other insects. Common to all these insects is the presence of two long regions with relatively well-conserved amino acid sequences, one near the N-terminal extending 267–282 residues (including two cysteines at conserved locations), and the other starting at position 450 to 655 and extending 279–283 residues, and of a region at the C-terminal extending some 200 residues (about 250 in Aedes aegypti due to the presence of a serine-rich stretch) with 10 cysteines at conserved locations. A molecular phylogenetic tree was constructed. 相似文献
130.
Identification of a penicillin-binding protein 3 homolog, PBP3x, in Pseudomonas aeruginosa: gene cloning and growth phase-dependent expression. 下载免费PDF全文
A homolog of Pseudomonas aeruginosa penicillin-binding protein 3 (PBP3), named PBP3x in this study, was identified by using degenerate primers based on conserved amino acid motifs in the high-molecular-weight PBPs. Analysis of the translated sequence of the pbpC gene encoding this PBP3x revealed that 41 and 48% of its amino acids were identical to those of Escherichia coli and P. aeruginosa PBP3s, respectively. The downstream sequence of pbpC encoded convergently transcribed homologs of the E. coli soxR gene and the Mycobacterium bovis adh gene. The pbpC gene product was expressed from the T7 promoter in E. coli and was exported to the cytoplasmic membrane of E. coli cells and could bind [3H] penicillin. By using a broad-host-range vector, pUCP27, the pbpC gene was expressed in P. aeruginosa PAO4089. [3H]penicillin-binding competition assays indicated that the pbpC gene product had lower affinities for several PBP3-targeted beta-lactam antibiotics than P. aeruginosa PBP3 did, and overexpression of the pbpC gene product had no effect on the susceptibility to the PBP3-targeted antibiotics tested. By gene replacement, a PBP3x-defective interposon mutant (strain HC132) was obtained and confirmed by Southern blot analysis. Inactivation of PBP3x caused no changes in the cell morphology or growth rate of exponentially growing cells, suggesting that pbpC was not required for cell viability under normal laboratory growth conditions. However, the upstream sequence of pbpC contained a potential sigma(s) recognition site, and pbpC gene expression appeared to be growth rate regulated. [3H]penicillin-binding assays indicated that PBP3 was mainly produced during exponential growth whereas PBP3x was produced in the stationary phase of growth. 相似文献