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931.
Dry Sintering Meets Wet Silver‐Ion “Soldering”: Charge‐Transfer Plasmon Engineering of Solution‐Assembled Gold Nanodimers From Visible to Near‐Infrared I and II Regions 下载免费PDF全文
Lingling Fang Yueliang Wang Miao Liu Prof. Ming Gong Prof. An Xu Prof. Zhaoxiang Deng 《Angewandte Chemie (International ed. in English)》2016,55(46):14296-14300
Achieving highly tunable and localized surface plasmon resonance up to near infrared (NIR) regions is a key target in nanoplasmonics. In particular, a self‐assembly process capable of producing highly uniform and solution‐processable nanomaterials with tailor‐made plasmonic properties is lacking. We herein address this problem through a conjunctive use of wet Ag+ soldering and dry thermal sintering to produce nanodimer‐derived structures with precisely engineered charge‐transfer plasmon (CTP). The sintered dimers are water soluble, featuring gradually shifted CTP spanning an 800 nm wavelength range (up to NIR II). Upon silica removal, the products are grafted by DNA to offer surface functionality. This process is also adaptable to DNA‐linked AuNP dimers toward plasmonic meta‐materials via DNA‐guided soldering and sintering. 相似文献
932.
Pei Gong Jian Wang Biaolan Liu Geying Ru Jiwen Feng 《Cellulose (London, England)》2016,23(3):1705-1711
Our NMR experiments show that chitin can dissolve well in aqueous KOH through a freeze-thawing process, and the dissolution power of the alkali solvent systems is in the order of KOH > NaOH > LiOH aqueous solution, which is totally contrary to that of cellulose in the alkali aqueous solution (i.e., LiOH > NaOH ? KOH). In this work, we systematically study the dissolution process in KOH and KOH/urea aqueous solutions. Chitin has good solubility (solubility ~80 %) in 8.4–25 wt% KOH aqueous solution at ?30 °C. The role of urea also has been investigated: unlike aqueous chitin-NaOH solutions, urea indeed enhances the solubility of chitin in KOH aqueous solutions, but the increased degree becomes unobtrusive with decreasing temperature and increasing dissolution time; the DA decline curves of chitin-KOH and chitin-KOH/urea aqueous solutions are nearly overlapping, indicating that the effect of the urea on the degree of acetylation of chitin in KOH aqueous solutions is small, similar to the NaOH/urea solvent. 相似文献
933.
An efficient and easy sample pretreatment methodology was proposed for the detection of photoinitiator 4‐methylbenzophenone from milk before high‐performance liquid chromatography. Appropriate conditions for demulsification were studied. The parameters affecting cloud point extraction, such as concentration of Tween‐20, electrolyte salt, equilibration temperature, and time, have been investigated. When the spiked level was 200–1000 μg/kg, the average addition standard recovery was 99.14–105.98% with the optimum cloud point extraction conditions (concentration of Tween‐20, 138 g/L; mass of anhydrous sodium sulfate, 0.75 g; equilibration temperature, 65°C; equilibration time, 30 min). To decrease the detection limits, further work about the organic solvent, shaking time, and ultrasonic parameters was carried. When the spiked level was 10–100 μg/kg, the average addition standard recovery was 70.40–106.91% with the optimum cloud point extraction and enrichment conditions (optimum cloud point extraction conditions; volume of cyclohexane, 30 mL; shaking time, 20 min; time of ultrasonic, 20 min; temperature of ultrasonic bath, 45°C). 相似文献
934.
First separation of four aromatic acids and two analogues with similar structures and polarities from Clematis akebioides by high‐speed counter‐current chromatography 下载免费PDF全文
Chengcheng Gong Tao Chen Huifeng Chen Shanshan Zhang Xinzhu Wang Weiqing Wang Jing Sun Yulin Li Zhixin Liao 《Journal of separation science》2016,39(23):4660-4666
In this paper, we report an efficient method by high‐speed counter‐current chromatography for the first separation of four aromatic acids and two analogs with similar structures and polarities from Clematis akebioides. First, the ethyl acetate extract was treated by silica gel column chromatography to enrich the target compounds. And then the fraction with target compounds were purified by high‐speed counter‐counter chromatography using a two‐phase solvent system consisting of chloroform/acetonitrile/water (10:6:4, v/v). The results showed high‐speed counter‐current chromatography could be a powerful technology for the separation of compounds with similar structures and polarities. Besides, it was found acetonitrile could be a good methanol substitute when a chloroform/methanol/water system could not provide a good separation factor. This study provides a reference for the separation of compounds from Clematis akebioides. 相似文献
935.
Room-Temperature Phosphorescence Turn-on Detection of DNA Based on Riboflavin-Modulated Manganese Doped Zinc Sulfide Quantum Dots 总被引:1,自引:0,他引:1
A sensitive phosphorescent sensor based on riboflavin (RF)-modulated mercaptopropionic acid (MPA)-capped Mn-doped ZnS quantum dots (QDs) was developed and utilized as room-temperature phosphorescence (RTP) sensor for DNA detection. The RTP of the MPA-capped Mn-doped ZnS QDs was stored via photoinduced electron transfer by RF, and formed an electrochemically nonactive QDs/RF nanohybrids through electrostatic attraction. In the presence of DNA, RF could bind with DNA, which has a double helical structure, via electrostatic interaction and intercalation. RF can be removed from the surface of the QDs, thus releasing the RTP of the QDs. On the basis of this principle, an RTP sensor for DNA detection was developed. Under optimal conditions, the detection limit for DNA was 15 μg mL?1, the relative standard deviation was 1.9 %, and the method recovery ranged from 97 % to 103 %. The proposed method was applied to biological fluids, in which satisfactory results were obtained. 相似文献
936.
Hui Li ShuJiang Zhang ChenLiang Gong JianZhi Wang Feng Wang 《Journal of fluorescence》2016,26(5):1555-1561
A new 4,5-diazafluorene-based fluorescent chemosensor has been synthesized by Schiff base condensation of 9,9-bis(3,5-dimethyl-4-aminophenyl)-4,5-diazafluorene with salicylaldehyde. The interaction of Schiff base with different metal ions has been studied over photofluorescent spectra. The results showed that Schiff base exhibited 194-fold enhancements in fluorescence at 465 nm after Zn2+ ions. Such fluorescent responses could be detected by naked eye under UV-lamp. The complex solution (L-Zn2+) exhibited reversibility with EDTA. 相似文献
937.
Huijuan Xie Yubing Gong Qi Wang 《The European Physical Journal B - Condensed Matter and Complex Systems》2016,89(7):161
In this paper, we numerically study how time delay induces multiple coherence resonance (MCR) and synchronization transitions (ST) in adaptive Hodgkin-Huxley neuronal networks with spike-timing dependent plasticity (STDP). It is found that MCR induced by time delay STDP can be either enhanced or suppressed as the adjusting rate Ap of STDP changes, and ST by time delay varies with the increase of Ap, and there is optimal Ap by which the ST becomes strongest. It is also found that there are optimal network randomness and network size by which ST by time delay becomes strongest, and when Ap increases, the optimal network randomness and optimal network size increase and related ST is enhanced. These results show that STDP can either enhance or suppress MCR and optimal STDP can enhance ST induced by time delay in the adaptive neuronal networks. These findings provide a new insight into STDP’s role for the information processing and transmission in neural systems. 相似文献
938.
Xiaozhuang Wang Yuekun Heng Zhi Wu Cheng Li Yongjie Sun Hongliang Dai Shengsen Sun Rongxing Yang Zhen Liu Ping Cao Jie Zhang Yun Wang Weijia Sun Siyu Wang Xiaolu Ji Jinzhou Zhao Wenxuan Gong Mei Ye Xiaoyan Ma Mingming Chen Meihang Xu Xiaolan Luo Kejun Zhu Zhenan Liu Xiaoshan Jiang 《The European Physical Journal C - Particles and Fields》2016,76(4):211
939.
940.
Lu W Du L Wang M Jia X Wen J Huang Y Guo Y Gong W Bao H Yang J Sun B 《Applied biochemistry and biotechnology》2007,142(1):17-28
A new method for breeding the hydrocortisone overproducing strain Curvularia lunata by screening ketoconazole-resistance mutant was developed. A hydrocortisone overproducing mutant C. lunata KA-91 with ketoconazole-resistance marker was obtained from protoplasts treated with ultraviolet radiation. The hydrocortisone
conversion rate of C. lunata KA-91 was increased by 42.1% compared to the original strain CL-114 at the substrate 17α-hydroxypregn-4-en-3, 20-dione-21-acetate
addition concentration of 1.0 g/L. The by-products produced by KA-91 were fewer than those of the original strain. It was
assumed that the higher cytochrome P450 content of ketoconazole-resistance mutant resulted in the increase of 11β-hydroxylation
capacity. The culture conditions for biotransformation of 17α-hydroxypregn-4-en-3, 20-dione-21-acetate to hydrocortisone were
optimized by response surface methodology. Plackett–Burman design was applied to elucidate the key factors affecting the hydrocortisone
production, and the results indicated that glucose, initial pH, and glucose to total nitrogen sources ratio (ω) had significant effects on hydrocortisone production. Box–Behnken design was employed to search for the optimal parameters
of those three key factors. According to the model, the trial checking at the optimal conditions showed a high hydrocortisone
conversion rate of 82.67%. 相似文献