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991.
Quantitative determination of soybean meal content in compound feeds: comparison of near-infrared spectroscopy and real-time PCR 总被引:1,自引:0,他引:1
Standard methods for determining the raw material content of compound feed are little exploited, except for the identification
of meat and bone meal in feeds. In this work, near-infrared (NIR) spectroscopy and real-time polymerase chain reaction (PCR)
were applied in order to establish new and fast methods for quantification of soybean meal content in compound feeds. The
best prediction quality was achieved by using a model based on NIR spectroscopy (R
2 = 0.9857, standard error of cross-validation 1.1065). Furthermore, a sensitive qualitative detection method by using the
real-time PCR was developed (R
2 = 0.976, slope −3.7599). Finally, the differences between the real-time PCR result and the NIR spectroscopy result for a
given sample were also treated, and we found that the NIR spectroscopy method provided quite accurate results which approach
closely those of the real-time PCR method.
Hui Li and Xiaowen Lv contributed equally to this work. 相似文献
992.
Li X Fekete A Englmann M Frommberger M Lv S Chen G Schmitt-Kopplin P 《Analytical and bioanalytical chemistry》2007,389(5):1439-1446
Since highly sensitive on-line coupling of UPLC with FTICR-MS is technically infeasible due to their different scan rates,
at-line coupling of these techniques was developed for rapid analysis. To enable cutting of one peak of the chromatogram into
one fraction, several conditions and relationships were investigated, e.g. the optimum volume of the inserted delay loop,
the relationship between retention time, loop outlet drop speed, individual drop volume versus mobile phase composition under
constant speed, and linear solvent strength gradient elution modes. Good and reproducible results were achieved applying UPLC
as an efficient separation and fast fractionation tool before the FTICR-MS measurements. A chip-based nanoelectrospray ionization
system was employed which was perfectly suited to handling the small-volume fractions and was thus chosen for the at-line
coupling. The method was initially applied to spiked extracts of cell-free bacterial culture supernatants in which bacterial
signalling compounds, namely N-acyl homoserine lactones (AHL), were detected. Good reproducibility and high recovery was observed. Afterwards, a culture
supernatant of Erwinia sp. JX3.2, a putative AHL producer, was investigated and N-hexanoyl-homoserine lactone was determined as a possible signalling molecule. More reliable assignments were achieved by
use of at-line coupling of UPLC and FTICR-MS compared with off-line measurements.
Xiaojing Li and Agnes Fekete have contributed equally to this publication. 相似文献
993.
高热值多面体硼氢化合物十氢十硼酸双四乙基铵的合成、热分解机理及动力学研究 总被引:3,自引:0,他引:3
以四氢硼酸四乙基铵为原料,通过热解反应合成了十氢十硼酸双四乙基铵,并采用红外光谱(IR),核磁共振波谱(1H NMR,11B NMR)及元素分析对其结构进行了表征.采用差热-热重(DSC-TG)分析研究了其在氩气及氧气气氛下的热稳定性,发现其在氩气中仅发生热分解反应,放热量较小,而在氧气中则先分解,再发生氧化反应并放出大量的热.采用Kissinger方法及Coat-redfern方程得到其热分解主反应的动力学方程,并进一步通过热裂解原位池-傅里叶变换红外光谱(FTIR)联用技术和同步热分析-红外-质谱(DSC-TGFTIR-MS)联用技术研究了其热分解机理,推测在加热升温过程中,化合物在303.2℃下快速分解,气相产物主要为乙烷与少量氨气及氢气,固相产物为单质硼. 相似文献
994.
995.
Microchimica Acta - We report on an electrochemical biosensor for the determination of the activity of dipeptidyl peptidase-IV (DPP-IV), and on a method for screening the effect of its inhibitors.... 相似文献
996.
淀粉基聚合物胶束用作药物载体 总被引:1,自引:0,他引:1
两亲性聚合物能通过亲疏水作用自组装为核-壳结构,而这独特的优势已使其成为在肿瘤靶向药物缓释方面具有很好发展前景的药物载体.淀粉原材料来源丰富,价格低廉,同时具有良好的生物相容性和生物可降解性,故基于淀粉的两亲性聚合物胶束正引起越来越多研究者极大的关注.作为药物载体,淀粉基聚合物胶束不仅可以提高药物的水溶性、延长药物在体内的循环时间、降低副作用和通过增强渗透与滞留(EPR)效应提高药物在靶向部位的优先累积,还可以在淀粉骨架上引入一些刺激响应型的官能团实现胶束快速靶向释药的功能.因此,淀粉基聚合物胶束在用作药物载体方面有着广阔的发展潜力.本文结合本课题组目前的研究工作和近几年的相关报道对淀粉基聚合物胶束作为药物载体的最新研究进展做简要综述. 相似文献
997.
The partial radial distribution function, coordination numbers, bond angles, F atoms type, self‐diffusion coefficient, viscosity, and ionic conduction of molten Na3AlF6 are investigated by first‐principles molecular dynamics simulation. 相似文献
998.
999.
Dr. Mengmeng Jiao Wenzhen Lv Wei Lü Qi Zhao Baiqi Shao Prof. Hongpeng You 《Chemphyschem》2015,16(4):817-824
A series of Eu2+‐, Ce3+‐, and Tb3+‐doped Ca2Ga2SiO7 phosphors is synthesized by using a high‐temperature solid‐state reaction. The powder X‐ray diffraction and structure refinement data indicate that our prepared phosphors are single phased and the phosphor crystalizes in a tetrahedral system with the ${P\bar 42m}$ (113) space group. The Eu2+‐ and Ce3+‐doped phosphors both have broad excitation bands, which match well with the UV light‐emitting diodes chips. Under irradiation of λ=350 nm, Ca2Ga2SiO7:Eu2+ and Ca2Ga2SiO7:Ce3+, Li+ have green and blue emissions, respectively. Luminescence of Ca2Ga2SiO7:Tb3+, Li+ phosphor varies with the different Tb3+ contents. The thermal stability and energy‐migration mechanism of Ca2Ga2SiO7:Eu2+ are also studied. The investigation results indicate that the prepared Ca2Ga2SiO7:Eu2+ and Ca2Ga2SiO7:Ce3+, Li+ samples show potential as green and blue phosphors, respectively, for UV‐excited white‐light‐emitting diodes. 相似文献
1000.
An ultra high performance liquid chromatography with tandem mass spectrometry method for plasma and cerebrospinal fluid pharmacokinetics of rhein in patients with traumatic brain injury after administration of rhubarb decoction 下载免费PDF全文
Yang Wang Rong Fan Jiekun Luo Tao Tang Zhihua Xing Zian Xia Weijun Peng Wenzhu Wang Huiying Lv Wei Huang Yizeng Liang Lunzhao Yi Hongmei Lu Xi Huang 《Journal of separation science》2015,38(7):1100-1108
Damage of blood–brain barrier is a common result of traumatic brain injury. This damage can open the blood–brain barrier and allow drug passage. An ultraperformance liquid chromatography with tandem mass spectrometry method was established to determine the concentration of rhein in the biofluids (plasma and cerebrospinal fluid) of patients with a compromised blood–brain barrier following traumatic brain injury after rhubarb administration. Furthermore, the pharmacokinetic profiles were analyzed. A triple‐quadruple tandem mass spectrometer with electrospray ionization was used for rhein detection. The mass transition followed was m/z 283.06→239.0. The calibration curve was linear in the concentration range of 10–8000 ng/mL for the biofluids. The intra‐ and interday precisions were less than 10%. The relative standard deviation of recovery was less than 15% in biological matrices. The pharmacokinetic data showed that rhein was rapidly transported into biofluids, and exhibited a peak concentration 1 h after rhubarb administration. The elimination rate of rhein was slow. The AUCcerebrospinal fluid/AUCplasma (AUC is area under curve) of rhein was approximately 17%, indicating that portions of rhein could pass the impaired blood–brain barrier. The method was successfully applied to quantify rhein in the biofluids of all patients. The data presented can help to guide clinical applications of rhubarb for treating traumatic brain injury. 相似文献