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991.
This paper describes the reaction of the simplest isocyanate, isocyanic acid, conveniently generated in situ from sodium cyanate, with nucleophilic carboxylate and amino residues in polyamide fibres. Changing the pH conditions greatly affects the outcome of these reactions: under acidic conditions the carboxylate residues are selectively carbamoylated, whereas under neutral conditions both residues are carbamoylated. Such modifications greatly change the dyeing behaviour of the treated substrates. The carboxylate carbamoylation reaction leads to the formation of amides rather than the carbamoylcarboxylate, which is a reactive intermediate. 相似文献
992.
Flore Mas Jessica Vereijssen David M. Suckling 《Journal of chemical ecology》2014,40(11-12):1197-1202
Candidatus Liberibacter solanacearum (CLso) is an unculturable bacterium vectored by the tomato potato psyllid (TPP) Bactericera cockerelli and has been associated with Zebra chip disease in potato and with other economically relevant symptoms observed in solanaceous crops. By altering their host and vector’s biological system, pathogens are able to induce changes that benefit them by increasing their transmission rate. Understanding these changes can enable better targeting of mechanisms to control pathogen outbreaks. Here, we explored how the CLso infectious status affects the volatile organic compounds (VOCs) of the tomato plant, and whether the CLso infectious status of TPP influences host plant settlement. These chemical and behavioral changes can ultimately affect the rate of encounter between the host and the vector. Results from headspace volatile collection of tomato plants showed that CLso infected tomato plants emitted a qualitatively and quantitatively different blend of VOCs compared to sham-infected plants. By a factorial experiment, we showed that CLso negative (CLso-) TPP preferred to settle 70 % more often on infected tomato plants, while CLso positive (CLso+) TPP were found 68 % more often on sham-infected tomato plants. These results provide new evidence in favor of both host and vector manipulation by CLso. 相似文献
993.
Tungsten hexacarbonyl and hydrogen peroxide as precursors for the growth of tungsten oxide thin films on titania nanoparticles 下载免费PDF全文
David H. K. Jackson Bryan A. Dunn Yingxin Guan Thomas F. Kuech 《American Institute of Chemical Engineers》2014,60(4):1278-1286
W(CO)6 and H2O2 were used in an atomic layer deposition (ALD)‐like process to grow thin WOx films onto TiO2 powders in a fluidized bed reactor. Carbonyl precursors are not widely used in this application, so that deviations from an ideal ALD process, previously not examined with W(CO)6, were identified. The resulting WOx films were a result of both ALD‐like and chemical vapor deposition‐based growth modes. A chemical reaction mechanism incorporating a combination of these two growth modes was inferred. As the move to expand the range of ALD precursors meets with the desire to scale up these processes, the simultaneous appearance of both these growth modes is likely to become more and more common, and so understanding the interaction of these two types of surface reactions is key to progress in the field. The films were observed to inhibit the anatase‐to‐rutile phase transformation in the TiO2 powders upon high temperature annealing, while crystallization of the amorphous WO3 was also not observed. Changes in the local bonding within the WO3 were observed and associated with changes in the structural nature of the film and its interface to the substrate. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1278–1286, 2014 相似文献
994.
Advanced Monte Carlo simulations of the adsorption of chiral alcohols in a homochiral metal‐organic framework 下载免费PDF全文
Zhiwei Qiao Ariana Torres‐Knoop David Dubbeldam David Fairen‐Jimenez Jian Zhou Randall Q. Snurr 《American Institute of Chemical Engineers》2014,60(6):2324-2334
Grand canonical Monte Carlo (GCMC) simulations with configurational biasing were used to study the enantioselective adsorption of four alkanols in a homochiral metal‐organic framework, known as hybrid organic‐inorganic zeolite analogue HOIZA‐1. Conventional GCMC simulations are not able to converge satisfactorily for this system due to the tight fit of the chiral alcohols in the narrow pores. However, parallel tempering and parallel mole‐fraction GCMC simulations overcome this problem. The simulations show that the enantioselective adsorption of the different (R,S)‐alkanols is due to the specific geometry of the chiral molecules relative to the pore size and shape. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2324–2334, 2014 相似文献
995.
Using Singular Value Decomposition to Characterize Protein–Protein Interactions by In‐cell NMR Spectroscopy 下载免费PDF全文
Subhabrata Majumder Christopher M. DeMott Dr. David S. Burz Dr. Alexander Shekhtman 《Chembiochem : a European journal of chemical biology》2014,15(7):929-933
Distinct differences between how model proteins interact in‐cell and in vitro suggest that the cytosol might have a profound effect in modulating protein–protein and/or protein–ligand interactions that are not observed in vitro. Analyses of in‐cell NMR spectra of target proteins interacting with physiological partners are further complicated by low signal‐to‐noise ratios, and the long overexpression times used in protein–protein interaction studies may lead to changes in the in‐cell spectra over the course of the experiment. To unambiguously resolve the principal binding mode between two interacting species against the dynamic cellular background, we analyzed in‐cell spectral data of a target protein over the time course of overexpression of its interacting partner by using single‐value decomposition (SVD). SVD differentiates between concentration‐dependent and concentration‐independent events and identifies the principal binding mode between the two species. The analysis implicates a set of amino acids involved in the specific interaction that differs from previous NMR analyses but is in good agreement with crystallographic data. 相似文献
996.
997.
Ketinun Kittipongpittaya Atikorn Panya Leqi Cui David Julian McClements Eric Andrew Decker 《Journal of the American Oil Chemists' Society》2014,91(11):1955-1965
Association colloids formed by surface active minor components play an important role in the oxidative stability of bulk oils. To imitate the formation of nanostructures in refined oils, multiple surface active minor components including phospholipids, free fatty acids, diacylglycerols and sterols were added to stripped corn oil. The critical micelle concentration (CMC) of the mixed components was determined. The impact of mixed minor components at below and above their CMC on oxidative stability of bulk oil and on antioxidant activity of α-tocopherol and Trolox was investigated. The CMC of the mixed surface active components in bulk oil was 20 µmol/kg oil in the presence of 383 ± 2 ppm of water. 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) played an important role on the formation of association colloids since it was the most important component in forming the association colloids as confirmed by CMC and fluorescence probe studies. The association colloids formed by the mixed components showed prooxidative activity in bulk oil as determined by monitoring the formation of lipid hydroperoxide and hexanal. The activity of α-tocopherol or Trolox was not changed by mixed components association colloids. These results suggest that association colloids both physically and chemically impacted the oxidative stability and activity of antioxidants in bulk oil. 相似文献
998.
Li Xing David C. Blakemore Arjun Narayanan Ray Unwalla Frank Lovering R. Aldrin Denny Huanyu Zhou Mark E. Bunnage 《ChemMedChem》2015,10(4):715-726
Anisole and fluoroanisoles display distinct conformational preferences, as evident from a survey of their crystal structures. In addition to altering the free ligand conformation, various degrees of fluorination have a strong impact on physicochemical and pharmacokinetic properties. Analysis of anisole and fluoroanisole matched molecular pairs in the Pfizer corporate database reveals interesting trends: 1) PhOCF3 increases log D by ~1 log unit over PhOCH3 compounds; 2) PhOCF3 shows lower passive permeability despite its higher lipophilicity; and 3) PhOCF3 does not appreciably improve metabolic stability over PhOCH3. Emerging from the investigation, difluoroanisole (PhOCF2H) strikes a better balance of properties with noticeable advantages of log D and transcellular permeability over PhOCF3. Synthetic assessment illustrates that the routes to access difluoroanisoles are often more straightforward than those for trifluoroanisoles. Whereas replacing PhOCH3 with PhOCF3 is a common tactic to optimize ADME properties, our analysis suggests PhOCF2H may be a more attractive alternative, and greater exploitation of this motif is recommended. 相似文献
999.
Discovery of Quinoline‐Derived Trifluoromethyl Alcohols,Determination of Their in vivo Toxicity and Anticancer Activity in a Zebrafish Embryo Model 下载免费PDF全文
Prof. Dr. Vinoth Sittaramane Jihan Padgett Philip Salter Ashley Williams Shauntelle Luke Rebecca McCall Prof. Dr. Jonathan F. Arambula Vincent B. Graves Mark Blocker David Van Leuven Keturah Bowe Julia Heimberger Hannah C. Cade Supriya Immaneni Prof. Dr. Abid Shaikh 《ChemMedChem》2015,10(11):1802-1807
In this study the rational design, synthesis, and anticancer activity of quinoline‐derived trifluoromethyl alcohols were evaluated. Members of this novel class of trifluoromethyl alcohols were identified as potent growth inhibitors in a zebrafish embryo model. Synthesis of these compounds was carried out with an sp3‐C?H functionalization strategy of methyl quinolines with trifluoromethyl ketones. A zebrafish embryo model was also used to explore the toxicity of ethyl 4,4,4‐trifluoro‐3‐hydroxy‐3‐(quinolin‐2‐ylmethyl)butanoate ( 1 ), 2‐benzyl‐1,1,1‐trifluoro‐3‐(quinolin‐2‐yl)propan‐2‐ol ( 2 ), and trifluoro‐3‐(isoquinolin‐1‐yl)‐2‐(thiophen‐2‐yl)propan‐2‐ol ( 3 ). Compounds 2 and 3 were found to be more toxic than compound 1 ; apoptotic staining assays indicated that compound 3 causes increased cell death. In vitro cell proliferation assays showed that compound 2 , with an LC50 value of 14.14 μm , has more potent anticancer activity than cisplatin. This novel class of inhibitors provides a new direction in the discovery of effective anticancer agents. 相似文献
1000.
Cover Picture: Discovery of MK‐8970: An Acetal Carbonate Prodrug of Raltegravir with Enhanced Colonic Absorption (ChemMedChem 2/2015) 下载免费PDF全文
Dr. Abbas M. Walji Dr. Rosa I. Sanchez Dr. Sophie‐Dorothee Clas Dr. Rebecca Nofsinger Dr. Manuel de Lera Ruiz Dr. Jing Li Dr. Amrithraj Bennet Christopher John Dr. David Jonathan Bennett Dr. John M. Sanders Christina N. Di Marco Somang Hope Kim Dr. Jaume Balsells Scott S. Ceglia Dr. Qun Dang Kimberly Manser Becky Nissley Dr. John S. Wai Dr. Michael Hafey Junying Wang Gene Chessen Dr. Allen Templeton Dr. John Higgins Dr. Ronald Smith Dr. Yunhui Wu Dr. Jay Grobler Dr. Paul J. Coleman 《ChemMedChem》2015,10(2):213-213