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91.
禽病原性大肠杆菌1型菌毛的分离与鉴定 总被引:4,自引:1,他引:4
以旋涡混合法使禽病原性大肠杆菌分离株566、1794和TK3菌毛脱落,经硫酸铵沉淀、透析后进行蔗糖密度梯度离心,收集密度为110至115g/cm3的蛋白带,经SDSPAGE测定,3株菌菌毛蛋白的分子量分别在175、170和170kD;提纯菌毛保留了甘露糖敏感性凝集豚鼠红细胞的能力,证明它们为1型菌毛;从1794株提取的1型菌毛免疫BALB/C小鼠产生的高免血清在Western blot中与3个菌株的相应菌毛蛋白均呈阳性反应。上述结果表明,受检的3株禽病原性大肠杆菌均表达了1型菌毛,其分子量在175~170kD之间,3个菌株的1型菌毛间具有较强的抗原相关性。 相似文献
92.
用于分化为多种类型细胞的多能干细胞(PSC)体外培养技术已被广泛应用于生物学领域中.由PSC分化而来的肾脏类器官可基本还原生物体内肾脏的组织结构和部分功能,在肾脏疾病模型研究和药物筛选中有重要作用,继续改善肾脏类器官的结构、功能和成熟度将会对肾脏再生治疗提供极大的帮助.研究肾脏类器官的重点在于体外准确模拟体内肾脏的发育... 相似文献
93.
Xiaohui Zhan Fengjuan Zhang Ziyang Zhong Ruhao Chen Yong Wang Ling Chang Ralph Bock Bihua Nie Jiang Zhang 《Plant biotechnology journal》2019,17(9):1814-1822
CRISPR/Cas systems provide bacteria and archaea with molecular immunity against invading phages and foreign plasmids. The class 2 type VI CRISPR/Cas effector Cas13a is an RNA‐targeting CRISPR effector that provides protection against RNA phages. Here we report the repurposing of CRISPR/Cas13a to protect potato plants from a eukaryotic virus, Potato virus Y (PVY). Transgenic potato lines expressing Cas13a/sgRNA (small guide RNA) constructs showed suppressed PVY accumulation and disease symptoms. The levels of viral resistance correlated with the expression levels of the Cas13a/sgRNA construct in the plants. Our data further demonstrate that appropriately designed sgRNAs can specifically interfere with multiple PVY strains, while having no effect on unrelated viruses such as PVA or Potato virus S. Our findings provide a novel and highly efficient strategy for engineering crops with resistances to viral diseases. 相似文献
94.
95.
The model conjugates phycocyanin-allophycocyanin (C-PC-APC) and phycoerythrocyanin-phycocyanin-allophycocyanin (PEC-C-PC-APC)
were synthesized by using a heterobifunctional coupling reagent N-succinimidyl-3-(2-pyridyldithio)propionate. The rod-core
complex (αβ)6
PCLRC
27(αβ)3
APCLC
8.9 and phycobilisomes were separated from Anabaena variabilis. Energy transfer features for the conjugates and the complexes
were compared. The absorption and fluorescence emission spectra indicated that the linker-peptides mediate interaction of
phycobiliproteins and prompt energy transfer. The energy transfer in the conjugates was detected by fluorescence emission
spectra and confirmed by the addition of dithiothreitol. The conjugates may be used as models for studying the energy transfer
mechanism in phycobilisomes.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
96.
Ma Zhong-You Pu Shun-Chang Jiang Jing-Jing Huang Bo Fan Mei-Zhen Li Zeng-Zhi 《World journal of microbiology & biotechnology》2011,27(3):679-686
A novel gene of thermostable phytase, phyA, was isolated by polymerase chain reaction (PCR) techniques from Aspergillus aculeatus RCEF 4894. The full-length phyA gene comprises 1,404 bp and encodes 467 amino-acid residues, including a 19-residue putative N-terminal signal peptide.
The phytase of A. aculeatus was a novel addition to the histidine-acid phosphatase family, as evidenced by both the conserved motifs RHGXRXP and HD in
the amino-acid sequence, and 3D structure models. The recombinant phytase was overexpressed in Pichia pastoris, and its specific activity reached 3,000 U mL−1 at the optimum pH of 5.5. This recombinant, thermostable phytase was able to withstand temperatures of up to 90 °C for 10 min,
with a loss of only 13.9% of initial enzymatic activity, and showed high activity with phytic-acid sodium salt at a pH range
of 2.5–6.5. The broad pH optima and high thermostability of the phytase makes it a promising candidate for feed-pelleting
applications. 相似文献
97.
Jabbarzadeh E Jiang T Deng M Nair LS Khan YM Laurencin CT 《Biotechnology and bioengineering》2007,98(5):1094-1102
Bone tissue engineering offers promising alternatives to repair and restore tissues. Our laboratory has employed poly(lactide-co-glycolide) PLAGA microspheres to develop a three dimensional (3-D) porous bioresorbable scaffold with a biomimetic pore structure. Osseous healing and integration with the surrounding tissue depends in part on new blood vessel formation within the porous structure. Since endothelial cells play a key role in angiogenesis (formation of new blood vessels from pre-existing vasculature), the purpose of this study was to better understand human endothelial cell attachment, viability, growth, and phenotypic expression on sintered PLAGA microsphere scaffold. Scanning electron microscopy (SEM) examination showed cells attaching to the surface of microspheres and bridging the pores between the microspheres. Cell proliferation studies indicated that cell number increased during early stages and reached a plateau between days 10 and 14. Immunofluorescent staining for actin showed that cells were proliferating three dimensionally through the scaffolds while staining for PECAM-1 (platelet endothelial cell adhesion molecule) displayed typical localization at cell-cell contacts. Gene expression analysis showed that endothelial cells grown on PLAGA scaffolds maintained their normal characteristic phenotype. The cell proliferation and phenotypic expression were independent of scaffold pore architecture. These results demonstrate that PLAGA sintered microsphere scaffolds can support the growth and biological functions of human endothelial cells. The insights from this study should aid future studies aimed at enhancing angiogenesis in three dimensional tissue engineered scaffolds. 相似文献
98.
Precise centromere mapping using a combination of repeat junction markers and chromatin immunoprecipitation-polymerase chain reaction 下载免费PDF全文
Luce AC Sharma A Mollere OS Wolfgruber TK Nagaki K Jiang J Presting GG Dawe RK 《Genetics》2006,174(2):1057-1061
Centromeres are difficult to map even in species where genetic resolution is excellent. Here we show that junctions between repeats provide reliable single-copy markers for recombinant inbred mapping within centromeres and pericentromeric heterochromatin. Repeat junction mapping was combined with anti-CENH3-mediated ChIP to provide a definitive map position for maize centromere 8. 相似文献
99.
太湖梅梁湾水体中悬浮质及光谱的分布特征 总被引:8,自引:1,他引:8
在研究太湖梅梁湾水体中的悬浮质及水体中光谱分布时发现:总悬浮质中无机悬浮质含量与总悬浮质之间呈现明显的正比线形关系(R2=0.9724),而有机悬浮质与总悬浮质之间的正比线形关系较弱(R2=0.2921);在20cm处以下,总悬浮质中的藻类含量随着水深度的增加呈现下降的趋势,表面略低;有机悬浮质与叶绿素a的含量之间的线形关系较弱(R2=0.1344);光谱的分布特征是:在水体的表面,绿光最强,蓝光较强,而红光最弱;在150cm以下,红光最强,绿光较强,蓝光最弱。 相似文献
100.
为观察瘦素诱导体外培养大鼠脂肪间充质干细胞凋亡的作用, 采用胶原酶消化法分离培养大鼠附睾脂肪垫间充质干细胞, 第3代细胞用于实验。细胞免疫荧光化学方法鉴定CD105、Vimentin表达阳性率约80%以上, 10-6 mol/L的瘦素作用细胞48 h、72 h后激光共聚焦显微镜观察分别可见早期及中晚期特征表现; 0 mol/L、10-8 mol/L、10-7 mol/L、10-6 mol/L瘦素分别作用于细胞48 h后, 应用AnnexinⅤ/PI双染色法流式细胞仪检测早期凋亡率分别为2.50%±0.72%、6.78%±1.99%、11.99%±1.58%、17.93%±4.82% (P<0.05); 随着瘦素浓度的增加和作用时间的延长, Caspase-3的活性逐渐增高, 至48 h时达到高峰。说明瘦素可以直接诱导脂肪间充质干细胞凋亡, 从数量上减少脂肪组织的含量。 相似文献