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871.
Heinz Fretz Katharina Ucci‐Stoll Paul Hug Joseph Schoepfer Marc Lang 《Helvetica chimica acta》2000,83(11):3064-3068
Electrophilic aromatic substitutions, such as halogenation and sulfonation, occur primarily para to the indole N‐atom at C(9) of the unique 12H‐pyrido[1,2‐a:3,4‐b′]diindole ring system of fascaplysin. 相似文献
872.
Marc R. Leduc Wayne Hayes Jean M. J. Frchet 《Journal of polymer science. Part A, Polymer chemistry》1998,36(1):1-10
The preparation and chemical modification of dendritic–linear block copolymers with surface functionalized dendritic components are presented. Isophthalate ester-functionalized dendrons featuring benzylic halide groups at their focal points have been used for the metal catalyzed “living” radical polymerization of styrene. The molecular weight of the dendritic–linear block copolymers determined by MALDI-TOF and Size Exclusion Chromatography was found to be accurately controlled up to molecular weights of ca. 30,000 a.m.u., with polydispersities less than 1.2. Subsequent functional group modifications of the peripheral ethyl ester groups of the dendritic block have been successfully carried out leading to carboxylic acids, butyl amides, benzyl alcohols, benzyl halides, and also accelerated generation growth via transesterification with a first generation dendritic alcohol. Several of these new dendritic–linear block copolymers exhibit interesting aggregation characteristics as evidenced by 1H-NMR spectroscopic studies. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1–10, 1998 相似文献
873.
A convenient preparation of N-(alkoxycarbonyl)-2,3-didehydroaspartic acid anhydrides 4 with substitution at the 3-position is reported. The key step is a cobalt-mediated acylation of an acetylene moiety, producing the highly functionalized didehydroamine acid derivative in good yield. Unnatural didehydroaspartates are readily accessible. 相似文献
874.
Marc Pignot Christoph Siethoff Michael Linscheid Elmar Weinhold 《Angewandte Chemie (International ed. in English)》1998,37(20):2888-2891
How to outwit a methyltransferase: Methyltransferases (Mtases) catalyze the transfer of the activated methyl group from the cofactor S-adenosyl-L -methionine ( 1 ) to acceptors R within a large variety of biomolecules. Through the use of the cofactor analogue 2 a whole nucleoside was coupled to DNA in a Mtase-catalyzed reaction. 相似文献
875.
Claude Spino Marc Pesant Yves Dory 《Angewandte Chemie (International ed. in English)》1998,37(23):3262-3265
The chronology of π-orbital mixing in the Diels–Alder cycloaddition of butadiene and ethylene differs for the two main interactions, the HOMOdiene–LUMOdieneophile and HOMOdienophile–LUMOdiene interactions. The C2−C3 π bond of the cycloadduct is already well developed at the level of the transition state, which is reminiscent of a late transition state. 相似文献
876.
Marc Gingras Alain Pinchart Carol Dallaire 《Angewandte Chemie (International ed. in English)》1998,37(22):3149-3151
“Megastars” with aromatic central cores, some of which fluoresce, were synthesized by the efficient connection of the side arms to the core by using the MacNicol reaction. Depending on the length of the side arm precursor, second-, third- (depicted), or fourth-generation molecular asterisks were obtained; a twelve-armed molecular asterisk was prepared when the benzene core was replaced by a coronene one. 相似文献
877.
878.
Jade Dussart-Gautheret Julia Deschamp Thibaut Legigan Maelle Monteil Evelyne Migianu-Griffoni Marc Lecouvey 《Molecules (Basel, Switzerland)》2021,26(24)
This paper reports on the synthesis of new hydroxymethylene-(phosphinyl)phosphonates (HMPPs). A methodology has been developed to propose an optimized one-pot procedure without any intermediate purifications. Various aliphatic and (hetero)aromatic HMPPs were synthesized in good to excellent yields (53–98%) and the influence of electron withdrawing/donating group substitution on aromatic substrates was studied. In addition, the one-pot synthesis of HMPP was monitored by 31P NMR spectroscopy, allowing effective control of the end of the reaction and identification of all phosphorylated intermediate species, which enabled us to propose a reaction mechanism. Optimized experimental conditions were applied to the preparation of biological relevant aminoalkyl-HMPPs. A preliminary study of the complexation to hydroxyapatite (bone matrix) was carried out in order to verify its lower affinity towards bone compared to bisphosphonate molecules. Moreover, in vitro anti-tumor activity study revealed encouraging antiproliferative activities on three human cancer cell lines (breast, pancreas and lung). 相似文献
879.
Miarintsoa Michaele Ranarijaona Ny Aina Harivony Rambala Rakotomena Mbolatiana Tovo Andrianjafy Fenia Diane Ramiharimanana Lydia Clarisse Herinirina Niry Hasinandrianina Ramarosandratana Benoit Briou Pauline Fajardie Patrick Mavingui Estelle Mtay Voahangy Vestalys Ramanandraibe Marc Lemaire 《Molecules (Basel, Switzerland)》2021,26(24)
This article describes a part of the results obtained from the cooperation between the University of Lyon1 (France) and the University of Antananarivo (Madagascar). It shows (among others) that useful research can be carried out in developing countries of the tropics if their social, technical, and economic conditions are taken into account. The concepts and methods associated with so-called “green chemistry” are particularly appropriated for this purpose. To illustrate this approach, two examples are shown. The first deals with industrial ecology and concerns waste transformation from the production of cashew nut into an amphiphilic product, oxyacetic derivatives. This product was obtained with a high yield and in a single step reaction. It exhibited an important surfactant property similar to those of the main fossil-based ones but with a much lower ecological impact. The second talks about chemical ecology as an alternative to insecticides and used to control dangerous mosquito populations. New substituted chromones were synthesized and showed biological activities toward Aedes albopictus mosquito species. Strong repellent properties were recorded for some alkoxylated products if others had a significant attractant effect (Kairomone) depending on their stereochemistry and the length of the alkyl chain. 相似文献
880.
Dorra Aissaoui-Zid Mohamed-Chiheb Saada Wassim Moslah Marie Potier-Cartereau Aude Lemettre Houcemeddine Othman Marc Gaysinski Zaineb Abdelkafi-Koubaa Soumaya Souid Naziha Marrakchi Christophe Vandier Khadija Essafi-Benkhadir Najet Srairi-Abid 《Molecules (Basel, Switzerland)》2021,26(24)
Glioblastoma is an aggressive cancer, against which medical professionals are still quite helpless, due to its resistance to current treatments. Scorpion toxins have been proposed as a promising alternative for the development of effective targeted glioblastoma therapy and diagnostic. However, the exploitation of the long peptides could present disadvantages. In this work, we identified and synthetized AaTs-1, the first tetrapeptide from Androctonus australis scorpion venom (Aa), which exhibited an antiproliferative effect specifically against human glioblastoma cells. Both the native and synthetic AaTs-1 were endowed with the same inhibiting effect on the proliferation of U87 cells with an IC50 of 0.56 mM. Interestingly, AaTs-1 was about two times more active than the anti-glioblastoma conventional chemotherapeutic drug, temozolomide (TMZ), and enhanced its efficacy on U87 cells. AaTs-1 showed a significant similarity with the synthetic peptide WKYMVm, an agonist of a G-coupled formyl-peptide receptor, FPRL-1, known to be involved in the proliferation of glioma cells. Interestingly, the tetrapeptide triggered the dephosphorylation of ERK, p38, and JNK kinases. It also enhanced the expression of p53 and FPRL-1, likely leading to the inhibition of the store operated calcium entry. Overall, our work uncovered AaTs-1 as a first natural potential FPRL-1 antagonist, which could be proposed as a promising target to develop new generation of innovative molecules used alone or in combination with TMZ to improve glioblastoma treatment response. Its chemical synthesis in non-limiting quantity represents a valuable advantage to design and develop low-cost active analogues to treat glioblastoma cancer. 相似文献