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991.
Heung‐Seop Yim Mi‐Ra Kim Gi‐Hyeon Sung Hyun‐A Chung Jin‐Kook Lee Sang‐Gyeong Lee Yong‐Jin Yoon 《Journal of heterocyclic chemistry》2008,45(1):215-220
trans‐2‐(2‐Aryl‐ or heteroarylvinyl)‐4,5‐dichloropyridazin‐3(2H)‐ones 3 were synthesized from 4,5‐dichloropyridazin‐3(2H)‐one via 2 step. The photochemical behavior of 3 in THF, methylene chloride, acetonitrile and methanol is dependent on the kind of aryl or heterocyclic ring and the solvent polarity 相似文献
992.
在二硫化碳(CS2)和苯(C6H6)的二元溶液中,随着相对体积浓度而变化,C6H6的基频ν1(992 cm-1) 的拉曼散射系数随浓度减小而增加,而CS2的基频ν1(656 cm-1)的拉曼散射系数则随浓度增加而增加。文章测量了这二元溶液相对不同体积浓度的拉曼光谱。结果表明,尽管CS2和C6H6的基频ν1的强度都随着浓度变化而发生较大变化,但C6H6的基频ν1对其参与的ν1+ν6~ν8费米共振几乎没有影响,而CS2的基频ν1强度的变化不仅对ν1~2ν2费米共振产生较大影响,还使基频ν2发生变化。文章给出了实验结果,并用Bertran费米共振理论和群论给予了解释。 相似文献
993.
Mi Zhong Wei Zeng Fu-Sheng Liu Bin Tang Qi-Jun Liu 《Surface and interface analysis : SIA》2019,51(10):1021-1032
The atomic structures, electronic properties, and surface stability of (001) and (011) surfaces of BaTiO3 are studied by first-principles calculations. Four differently terminated BaTiO3 surfaces are considered in this study, including (001)-BaO, (001)-TiO2, (011)-BaTiO, and (011)-O2 terminations. The relaxations and rumplings are calculated and discussed, finding that the first layer relaxes inwards, while the second layer relaxes outwards for (001) and (110) surfaces. The data obtained for electronic properties show that O2p states in (001)-BaO/(001)-TiO2 termination shift to the lower/higher energy region, leading to a wide/narrow band gap. And the new produced surface states are observed in (011) surface terminations, which is mainly attributed to the supplied electrons from outermost surface atoms, even O atoms are oxidized. Furthermore, the (001) surface of BaTiO3 is found to be more stable than the (011) surface according to the predicted surface energy which is 0.86 and 2.92 J/m2 for (001) and (011) surfaces, respectively. Of which, BaO termination is predicted to be more likely to cleavage from the (001) direction than the TiO2 termination is. 相似文献
994.
Jiang Wen Xing Xianjun Zhang Xianwen Zhang Xuefei Mi Mengxing 《Journal of Thermal Analysis and Calorimetry》2019,136(2):803-813
Journal of Thermal Analysis and Calorimetry - In this paper, wheat straw, corn straw and sorghum straw were used as raw materials. KOH and NaOH were used as catalysts to prepare straw pyrolytic... 相似文献
995.
Mi Liu Mingzhen He Hongwei Gao Sa Guo Jia Jia Hui Ouyang Yulin Feng Shilin Yang 《Biomedical chromatography : BMC》2019,33(11)
Gynura procumbens (Lour.) Merr. is traditionally used as a raw material for making dumplings or steamed stuffed buns, and its fresh leaves are boiled with water for tea. Herein, we established an ultra‐high–performance liquid chromatography–quadrupole time‐of‐flight mass spectrometry (UHPLC–Q‐TOF–MS/MS) combined with characteristic ion filtration (CIF) strategy to rapidly screen active ingredients with antioxidant and anti‐inflammatory properties in G. procumbens. This strategy involved screening the active part of G. procumbens using antioxidation and anti‐inflammatory activity assays; discovering the active compounds by speculating on the active site's chemical composition by UHPLC–Q‐TOF–MS/MS plus CIF; and verifying the active compounds' activities. The ethyl acetate extract (EEAF) of G. procumbens was the major active site. Eighty‐one compounds were identified from the EEAF using UHPLC–Q‐TOF–MS/MS plus CIF. Furthermore, polyphenols such as cynarine, isochlorogenic acids A and isochlorogenic acids C have excellent antioxidizing and anti‐inflammatory activities. This study provides a practical strategy for rapid in vitro screening of the antioxidizing and anti‐inflammatory activities of traditional vegetables and herbs and identification of active ingredients. 相似文献
996.
Weijun Li Feifei Luo Ling Zhang Shuanma Yan Ruiyang Zhao Ning Ren Yizhao Wu Yuliang Chen Yujie Dong Mi Ouyang Cheng Zhang 《Journal of polymer science. Part A, Polymer chemistry》2019,57(23):2340-2348
Here the authors designed and synthesized three branched thiophene polymers with different effective conjugation lengths of thiophene groups, pTPBT, pTPTT, and pTPQT, mainly based on bithiophene, trithiophene, and quadruple thiophene. The electrochemical curves and theoretical calculation results reflect that the oxidation potential of polymers decreased gradually as the conjugation lengths of thiophene groups increased, which is favorable for the appearance of electrochromism. Electrochromic properties demonstrate that pTBTT displays no electrochromism, pTPTT exhibits an unstable one, while pTPQT shows an obvious stable electrochromism between yellow‐orange and blue‐violet colors. These results indicate that thiophene polymers with effective electrochromism should be the smallest conjugation length of quadruple thiophene at least. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2340–2348 相似文献
997.
998.
目的 探讨脑外伤患者血浆脂联素水平的变化规律及与脑外伤严重度的相关性。方法 选取86例重型脑外伤患者和86例健康体检者,分别于入院时、入院后第1、2、3、5、7天和体检时清晨空腹抽取静脉血,ELISA 法测定血浆脂联素水平。结果 脑外伤后血浆脂联素水平6h内升高,24h到达高峰,后逐渐下降,入院时、入院后第1、2、3、5、7天的血浆脂联素水平均明显高于健康对照组(均P<0.01);蛛网膜下腔出血、环池消失、中线移位(>5mm)和瞳孔散大患者各个时间点血浆脂联素水平显著高于其对照组(均P<0.01)。入院时格拉斯哥昏迷评分与各个时间点血浆脂联素水平均呈负相关(均P<0.01)。结论 脑外伤后血浆脂联素水平升高,与脑外伤严重度显著相关。 相似文献
999.
1000.
Dr. Fen Wang Dr. Zisong Qi Yuxia Zhao Shuailei Zhai Dr. Guangfan Zheng Ruijie Mi Dr. Zhiyan Huang Dr. Xiaolin Zhu Prof. Dr. Xiaoming He Prof. Dr. Xingwei Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13390-13396
Reported herein is the atroposelective synthesis of biaryl NH isoquinolones by RhIII-catalyzed C−H activation of benzamides and intermolecular [4+2] annulation for a broad scope of 2-substituted 1-alkynylnaphthalenes, as well as sterically hindered, symmetric diarylacetylenes. The axial chirality is constructed based on dynamic kinetic transformation of the alkyne in redox-neutral annulation with benzamides, with alkyne insertion being stereodetermining. The reaction accommodates both benzamides and heteroaryl carboxamides and proceeds in excellent regioselectivity (if applicable) and enantioselectivities (average 91.8 % ee). An enantiomerically and diastereomerically pure rhodacyclic complex was prepared and offers insight into enantiomeric control of the coupling system, wherein the steric interactions between the amide directing group and the alkyne substrate dictate both the regio- and enantioselectivity. 相似文献