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101.
Seyed M. Mirvakili Joanna E. Slota Ashwin R. Usgaocar Ali Mahmoudzadeh Daniel Jun Mehr Negar Mirvakili J. Thomas Beatty John D. W. Madden 《Advanced functional materials》2014,24(30):4789-4794
Highly efficient light absorption and charge separation within the photosystem and reaction center (RC) complexes of photosynthetic plants and bacteria are of great interest for solar cell and photo detector applications, since they offer almost unity quantum yield and expected ultimate power conversion efficiencies of more than 18% and 12%, respectively. In addition, the charge separated states created by these protein complexes are very long lived compared to conventional semiconductor solar cells. In this work, a novel technique is presented for the deposition of photosynthetic protein complexes, by electrospraying RCs of Rhodobacter sphaeroides onto highly ordered pyrolytic graphite (HOPG) electrodes. Remarkably, it is shown that the RCs not only survive exposure to the high electric fields but also yield peak photocurrent densities of up to 7 μA cm?2, which is equal to the highest value reported to date. 相似文献
102.
Flow regulators are added to solid pharmaceutical formulations to improve the flow properties of powder mixtures. During the blending process the glidants adsorb successively at the surface of the host particles and thus lead to a reduction of attractive forces. A large variety of flow additives based on silicon dioxide is commercially available, but not all glidants are just as well suited for each technological problem or each cohesive bulk powder. To assess the improvement of the flowability parameters caused by a glidant a classification system and an adequate measuring device is needed. We would like to present a new measuring device to evaluate the flow enhancing potency of glidants. The modified outflow funnel features a stirrer that acts in the region of bulk arches obstructing the outflow process of a cohesive powder. By destruction of the bulk arches powder outflow is enabled and the time needed for emanation can be measured as a parameter of the flow properties. In addition other measuring parameters like the force needed to destroy the bulk arches are capable to evaluate the flowability of the powder mixture. Binary powder mixtures consisting of corn starch and flow regulator were blended in a Turbula® mixer for a defined period of time. The flow regulators were represented by fumed silica and a selection of various types of SIPERNAT® precipitated silica provided by Evonik Degussa GmbH, Hanau, Germany. Flowability parameters of the mixtures were characterized with a modified outflow funnel, Hausner Ratio and a shear tester. 相似文献
103.
Agnieszka Wróblewska Joanna Wajzberg Anna Fajdek Eugeniusz Milchert 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(9):1344-1349
BACKGROUND: The influence of technological parameters on the epoxidation of 1‐butene‐3‐ol (1B3O) over titanium silicalite TS‐2 catalyst has been investigated. Epoxidations were carried out using 30%(w/w) hydrogen peroxide at atmospheric pressure. The major product from the epoxidation of B3O was 1,2‐epoxybutane‐3‐ol, with many potential applications. RESULTS: The influence of temperature (20–60 °C), 1B3O/H2O2 molar ratio (1:1–5:1), methanol concentration (5–90%(w/w)), TS‐2 catalyst concentration (0.1–6.0%(w/w)) and reaction time (0.5–5.0 h) have been studied. CONCLUSION: The epoxidation process is most effective if conducted at a temperature of 20 °C, 1B3O/H2O2 molar ratio 1:1, methanol concentration (used as the solvent) 80%(w/w), catalyst concentration 5%(w/w) and reaction time 5 h. Copyright © 2009 Society of Chemical Industry 相似文献
104.
Ana B. Castro-Ceseña M. Pilar Sánchez-Saavedra Ekaterina E. Novitskaya Po-Yu Chen Gustavo A. Hirata Joanna McKittrick 《Materials science & engineering. C, Materials for biological applications》2013,33(8):4958-4964
The present study proposes an interpretation of the mechanism of bone deproteinization. Cortical and trabecular bovine femur bones were deproteinized using 6% NaOCl (37, 50, 60 °C). The kinetic parameters (rate constant and activation energy) were calculated, and the surface area of each type of bone was considered. A statistical analysis of the rate constants shows that cortical bone deproteinizes at a lower rate than trabecular. The activation energy is higher for trabecular than cortical bone, and no significant differences are found in the protein concentration values for both bones. Therefore, although trabecular bone deproteinizes at a higher rate than cortical, trabecular bone requires more energy for the deproteinization reaction to take place. Considering that both types of bones are constituted by mineral, protein, and water; the present work shows that the individual inner matrix architecture of trabecular and cortical bones, along with characteristics such as the mineral concentration and its bonding with collagen fibers, may be the responsible factors that control protein depletion. 相似文献
105.
Expository Text Comprehension in the Primary Grade Classroom. 总被引:1,自引:0,他引:1
Williams Joanna P.; Hall Kendra M.; Lauer Kristen D.; Stafford K. Brooke; DeSisto Laura A.; deCani John S. 《Canadian Metallurgical Quarterly》2005,97(4):538
This study investigates the effectiveness of an instructional program designed to teach 2nd graders how to comprehend compare-contrast expository text. Along with introducing new content (animal classification), the program emphasizes text structure via clue words, a sequence of questions, and a graphic organizer, and via the close analysis of specially constructed exemplar paragraphs. The authors compared the program with (a) more traditional instruction that focused only on the new content and (b) a no instruction control; 128 7- and 8-year-olds participated. Classroom teachers provided the instruction. The program improved students' ability to comprehend compare-contrast texts. Students were able to demonstrate transfer to uninstructed compare-contrast texts though not to text structures other than compare-contrast. Moreover, the text structure instruction did not detract from their ability to learn new content. The results provide evidence, heretofore lacking, that explicit instruction in comprehension is feasible and effective as early as the 2nd grade. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
106.
Examines the influence of lesbian family structure on parenting within the context of both psychodynamic and family systems theories by providing a review of the literature, as well as information based on the author's clinical work with lesbians and their families. The uniqueness of the lesbian family is considered, and the varieties of lesbian family structure are outlined (e.g., blended, single parent, couples having children together, donors, and noncustodial fathers). The impact of parenting is discussed in terms of common issues in lesbian distance and boundary regulation, power/equality, shared parenting, relationships with extended families, lesbian friendship networks, and issues unique to lesbian "divorce." (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
107.
Small-pore CoAlPO-34 materials were synthesized with a variety of organic template molecules and were characterized in detail, employing microcrystal diffraction, powder diffraction and in situ combined XRD/XAS techniques. We found that, when two template molecules or two nitrogen atoms of a single template molecule are present inside the chabazitic cage, the concentration of cobalt present in the system is ca. 25?at%, which introduces instability in the framework structure during the removal of the organic template. In contrast, when only one template molecule is present, it is possible to control the concentration of Co(II) ions in the framework to ca. 10?at%; these systems show good structural integrity and redox chemistry that was exploited for the regio-selective conversion of linear alkane molecules. 相似文献
108.
109.
Joanna Kulesza Bráulio Silva Barros Severino Alves Júnior Carlos Alberto Fernandes de Oliveira Dulce Maria de Araújo Melo Jaroslaw Chojnacki 《Materials Chemistry and Physics》2014
Hydro(solvo)thermal reactions of Cu(NO3)2·2.5H2O or Zn(NO3)2·6H2O with 1,3-H2bdc provided two structurally different coordination polymers; a 2D network “metallacalixarene” based on the paddlewheel-type cluster with the formula [Cu(1,3-bdc)·H2O]·H2O (1) and a 3D framework [Zn(1,3-bdc)] (2), respectively. The use of a base was unnecessary in this synthesis; however, the presence of benzene played a crucial role in the crystallization of the desired products and could act as a template molecule in the synthesis of polymer (1). The unsaturated apical sites in the Cu2 cluster of polymer (1) were occupied by water molecules, what consequently led to the structural decomposition of the framework after exposing the sample in air, which was not the case of the Zn-coordination polymer (2). 相似文献
110.