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991.
992.
在药剂学课程教学中,为讲解传授“手性”相关的知识和概念,设计了一种新的教学法,并进行了实践应用。通过对该教学方法的总结和提炼,将以上教学法命名为“以问题为导向的点-面式教学法”。该教学法是以“反应停”具体事例为问题引导,提出和确定问题后,引出知识点,从药学相关领域知识面展开教学活动后,进行知识点总结,最后达成最终的教学目标。该教学法对教学实践工作有一定的参考价值。 相似文献
993.
994.
以《化学反应原理》中“盖斯定律”这一教学内容为例,基于发展高中生的化学核心素养为目的确立本课时教学目标,将“理解盖斯定律的本质”“应用盖斯定律计算反应热”这2个问题的讨论作为重点,主要从“证据推理与模型认知” “科学态度与社会责任”2个维度,探讨如何在化学课堂上发展高中生的化学核心素养,探索素养为本的有效课堂教学模式。 相似文献
995.
针对分析化学课程教学中存在的问题,结合课程特点和专业人才培养目标,从基于专业特色设置课程、有针对性地展开教学、完善教学评价模式、提高教学资源利用率等4个方面对分析化学教学改革进行了探索。 相似文献
996.
A monolithic capillary column with a mixed‐mode stationary phase of reversed‐phase/hydrophilic interaction chromatography was prepared for capillary liquid chromatography. The monolith was created by an in‐situ copolymerization of a homemade monomer N,N‐dimethyl‐N‐acryloxyundecyl‐N‐(3‐sulfopropyl) ammonium betaine and a crosslinker pentaerythritol triacrylate in a binary porogen agent consisting of methanol and isopropanol. The functional monomer was designed to have a highly polar zwitterionic sulfobetaine terminal group and a hydrophobic long alkyl chain moiety. The composition of the polymerization solution was systematically optimized to permit the best column performance. The columns were evaluated by using acidic, basic, polar neutral analytes, as well as a set of alkylbenzenes and Triton X100. Very good separations were obtained on the column with the mixed‐mode stationary phase. It was demonstrated that the mixed‐mode stationary phase displayed typic dual retention mechanisms of reversed‐phase/hydrophilic interaction liquid chromatography depending on the content of acetonitrile in the mobile phase. The method for column preparation is reproducible. 相似文献
997.
Wenfen Zhang Yongming Zhang Guangrui Zhang Xin Ba Shaige Xia Wuduo Zhao Dan Yin Shusheng Zhang 《Journal of separation science》2019,42(7):1374-1383
A new water‐soluble tetra‐proline‐modified calix[4]arene‐bonded silica stationary phase was prepared straightforwardly by an indirect method and characterized by elemental analysis, energy dispersive Spectrometry, solid‐state 13C NMR spectroscopy, Fourier‐transform infrared spectroscopy, and thermogravimetric analysis. Due to the simultaneous introduction of polar tetra‐proline and nonpolar calix[4]arene, the developed column possessing a double retention mode of reverse‐phase liquid chromatography and hydrophilic interaction liquid chromatography. A series of hydrophobic and hydrophilic test samples, including nucleosides and nucleotides, amines, monosubstituted benzenes, chiral compounds, and phenols, were used to evaluate the developed stationary phase. A rapid separation capability, high separation efficiency, and selectivity were achieved based on the multiple interactions between solutes and tetra‐proline‐modified calix[4]arene‐bonded silica stationary phase. Moreover, the developed stationary phase was further used to detect and separate hexamethylenetetramine in rice flour. All the results indicated the potential merits of the developed stationary phase for simultaneous separation of complex hydrophobic and hydrophilic samples with high selectivity. 相似文献
998.
Genlin Sun Jeong Soo Kim Yune Sung Kim Hyun Joo An Won Jo Cheong 《Journal of separation science》2019,42(16):2612-2620
A stationary phase was prepared by chemical derivatization of the support particles with a layer of copolymer composed of styrene and N‐phenyl acrylamide. Silica monolith particles of ca. 2.6 µm (volume‐based average) have been prepared as the support particles by sol‐gel reaction followed by differential sedimentation. The particles were reacted with 3‐chloropropyl trimethoxysilane followed by sodium diethyldithiocarbamate to introduce an initiator moiety. Then, the copolymer layer was immobilized via reversible addition‐fragmentation transfer polymerization. The resultant phase was packed in glass‐lined stainless‐steel micro‐columns (1 x 150 mm) and evaluated for the separation of a mixture composed of five peptides (Trp‐Gly, Thr‐Tyr‐Ser, angiotensin I, isotocin and bradykinin). The effect of monomer mixing ratio (styrene versus N‐phenyl acrylamide) on the chromatographic separation efficiency of the stationary phase was examined. A number of theoretical plates (N) as high as 33 600 plates/column (224 000 plates/m, 4.46 µm plate height) was achieved using the column packed with the optimized stationary phase. The column‐to‐column reproducibility based on three columns packed with three different batches of stationary phase was found satisfactory in separation efficiency, retention factor, and asymmetry factor. 相似文献
999.
Xin‐Yi Huang Xia Zhang Dong Pei Jian‐Fei Liu Yuan Gong Haji Akber Aisa Duo‐Long Di 《Journal of separation science》2019,42(11):2080-2088
In this work, a continuous high‐speed countercurrent chromatography method has been developed on the basis of elution‐extrusion mode and this method was successfully applied to the separation of maslinic and oleanolic acid from the extract of olive pulp. In the process of ‘elution’, the sample solution was continuously loaded into the column and the maslinic acid was steadily eluted out in this step while highly retained oleanlic acid always stayed in the column. In the process of ‘extrusion’, the oleanlic acid was pushed out of the column with the stationary phase. In this way, we achieved a large sample loading. A total of 120 mL sample solution (about 89.55% of the column volume) which contains 600 mg olive pulp extract was pumped in the apparatus by a constant‐flow pump and the maslinic and oleanolic acids were largely separated within 120 min. Both of these two compounds presented high yields and high purities (271.6 mg for maslinic acid with 86.7% and 83.9 mg oleanolic acids with 83.4%). 相似文献
1000.
Genlin Sun Ashraf Ali Yune Sung Kim Jeong Soo Kim Hyun Joo An Won Jo Cheong 《Journal of separation science》2019,42(24):3621-3630
A phase with both hydrophobic and hydrophilic functionalities has been synthesized by modification of ground silica monolith particles with C18 and 1‐[3‐(trimethoxysilyl)propyl] urea ligands. A series of phases was prepared by changing the ratio of the two ligands to determine the optimal ratio in view of separation efficiency. The resultant optimized stationary phase was packed in narrow‐bore glass‐lined stainless‐steel columns (1 × 300 mm and 2.1 × 100 mm) and used for the separation of synthetic peptides and proteins. The average numbers of theoretical plates (N) of 52 100/column (174 000/m, 5.75 µm plate height) and 35 500/column (118 000/m, 8.47 µm plate height) were achieved with the 300 mm column at a flow rate of 25 µL/min (0.86 mm/s) in 60:40 v/v acetonitrile/30 mM aqueous ammonium formate for the mixture of peptides (Thr‐Tyr‐Ser, Val‐Ala‐Pro‐Gly, angiotensin I, isotocin, and bradykinin) and for the mixture of proteins (myoglobin, human serum albumin, and insulin), respectively. Fast analysis of the peptides and proteins was also carried out at a flow rate of 0.9 mL/min (6.88 mm/s) with the 100 mm column and all the analytes were eluted within 2 min with good separation efficiency. 相似文献