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1.
2.
Paresh Parekh Sayaka Ohno Shin‐ichi Yusa Chao Lv Binyang Du Debes Ray Vinod Kumar Aswal Pratap Bahadur 《Polymer International》2020,69(11):1113-1121
Poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) triblock copolymer (Pluronic F127) was modified by introducing poly(N‐isopropylacrylamide) (PNIPAM) at both the PEO ends, and the pentablock copolymer (PNIPAM41–F127–PNIPAM41, PN41) so prepared was characterized using gel permeation chromatography and 1H NMR spectroscopy. The degree of polymerization of NIPAM blocks at the two ends was 41. The solution behaviour and microstructure of PN41 aggregates in water were examined using UV–visible spectroscopy, micro‐differential scanning calorimetry and small‐angle neutron scattering (SANS) and compared with F127. Two lower critical solution temperatures (LCSTs) were observed for the pentablock copolymer, corresponding to PPO and PNIPAM blocks, respectively. The adsorption of PN41 on thiol‐grafted hydrophobic gold surfaces at various temperatures was investigated using a quartz crystal microbalance. It was found that the adsorption behaviour and mechanism of PN41 were mainly determined by the interactions of the pentablock copolymers with different chain conformations in dilute aqueous solutions at various temperatures. SANS measurements were used to determine the temperature‐dependent structural evolution of polymer micelles in aqueous solution. A NOESY study revealed that above the LSCT of PNIPAM, the interaction of PPO and PNIPAM protons increases and the distance between PPO and PNIPAM decreases. © 2019 Society of Chemical Industry 相似文献
3.
New mobile computing technologies require new paradigms for infrastructure and interaction with mobile and networked devices. For building smart mobile companions for new intelligent services, a number of challenges have to be addressed. We argue that artificial intelligence is a key to a new generation of mobile systems. In this introduction to AI in mobile systems, we present some of the challenges and solutions in this exciting field of research. 相似文献
4.
The results on changes in the apparent hydrodynamic diameter (Dh) of micelles in a solution containing 5% of a moderately hydrophobic/hydrophilic triblock PEO-PPO-PEO copolymer in the presence
of several hydroxyl compounds at 23 °C from dynamic light scattering (DLS) are reported. Distribution plots show micelles
with hydrodynamic diameter ~17 nm and low polydispersity (<0.1) except at low concentrations where a unimer peak (~ 4 nm)
was also noticed. These additives increase/decrease the micelle size and show micellar transition depending upon their hydrophilicity/hydrophobicity.
The results are discussed in terms of the effect of the additives on altering water structure and their partitioning in micelle.
Short chain alcohols (C1–C3) increase solvation of PEO and thus increase micelle hydrodynamic size while higher alcohols, initially reduce Dh due shrinkage of PEO followed by micellar growth at higher concentrations. Among αω-alkanediols, C2 and C4 diols increase micelle size by immobilizing water sphere around the micelles whereas higher diols form wicket like structures
and reside in palisade layer. Isomeric hexanediols (1,2; 1,5; 2,5 and 1,6) alter micelle size in different ways depending
on their hydrophobicity. In C6EO
m
(m = 0, 1, 2), as the number of EO group increases, it becomes more hydrophilic and increases Dh at higher concentration. Addition of a hydrophobic triblock copolymer leads to unfavorable mixing with a moderately hydrophobic/hydrophilic
triblock copolymer which results in increase in size, while the addition of a hydrophilic counterpart increases the average
hydrodynamic size and follows appearance of unimer peak. 相似文献
5.
Preservation of protein fluorescence in embedded human dendritic cells for targeted 3D light and electron microscopy 下载免费PDF全文
K. HÖHN J. FUCHS A. FRÖBER R. KIRMSE B. GLASS M. ANDERS‐ÖSSWEIN P. WALTHER H.‐G. KRÄUSSLICH C. DIETRICH 《Journal of microscopy》2015,259(2):121-128
In this study, we present a correlative microscopy workflow to combine detailed 3D fluorescence light microscopy data with ultrastructural information gained by 3D focused ion beam assisted scanning electron microscopy. The workflow is based on an optimized high pressure freezing/freeze substitution protocol that preserves good ultrastructural detail along with retaining the fluorescence signal in the resin embedded specimens. Consequently, cellular structures of interest can readily be identified and imaged by state of the art 3D confocal fluorescence microscopy and are precisely referenced with respect to an imprinted coordinate system on the surface of the resin block. This allows precise guidance of the focused ion beam assisted scanning electron microscopy and limits the volume to be imaged to the structure of interest. This, in turn, minimizes the total acquisition time necessary to conduct the time consuming ultrastructural scanning electron microscope imaging while eliminating the risk to miss parts of the target structure. We illustrate the value of this workflow for targeting virus compartments, which are formed in HIV‐pulsed mature human dendritic cells. 相似文献
6.
W Wang JL Abbruzzese DB Evans L Larry KR Cleary PJ Chiao 《Canadian Metallurgical Quarterly》1999,5(1):119-127
To assess the efficiency of nasally administered cartilage-specific collagens as vaccination against development of arthritis and to ameliorate already established chronic arthritis, experimental models which develop chronic arthritis, pristane-induced arthritis (PIA), and homologous collagen-induced arthritis (CIA) in the rat were selected. Cartilage-specific collagens type IX (CIX) and type II (CII) were used for vaccination intranasally. A single dose of 250 microg CII instilled intranasally in rats with established PIA ameliorated the disease. For the prevention of disease, the same dose given before immunization was found to be most effective. Most importantly, the disease was more severe if this dose was given three times. For treatment of PIA, CIX was found to be more effective than CII, whereas for treatment of CIA only CII was effective. The amelioration of CIA was associated with a marked suppression of delayed type hypersensitivity and the flare reaction to CII and lower levels of IgG2b anti-CII antibodies in serum, i.e., with suppression of the TH1 rather than the TH2 response to CII. These findings, that cartilage proteins, if given intranasally, can both prevent and ameliorate established chronic arthritis in rats, are of significant importance for possible use in rheumatoid arthritis. The identification of two different cartilage-specific proteins (CII and CIX) effective against a disease induced with a well-defined nonimmunogenic adjuvant such as pristane will be of value for enhancing the effectiveness of the treatment. 相似文献
7.
OBJECTIVE: To propose a definition for stage IA1 cervical adenocarcinoma, based on the International Federation of Gynecology and Obstetrics (FIGO) staging system, and to determine if patients meeting criteria might be candidates for conservative surgery. METHODS: Two hundred women were diagnosed with early-stage cervical adenocarcinoma from 1982 to 1996. Histopathologic sections were reviewed by a gynecologic pathologist. Medical records were reviewed, and patients included in this study had microscopically identifiable lesions, up to 3 mm invasive depth, up to 7 mm tumor width, and negative margins if cone biopsy was performed. RESULTS: Twenty-one patients with microinvasive adenocarcinoma met criteria for FIGO stage IA1 carcinoma of the cervix. The median (range) follow-up was 76 (30-172) months and median (range) patient age was 38 (24-75) years. Definitive treatment included type II or III radical hysterectomy in 16 cases, simple abdominal or vaginal hysterectomy in four cases, and loop electrosurgical excision procedure in one case; one patient received adjuvant pelvic radiation. The histologic subtypes were endocervical adenocarcinoma in 18 cases, adenosquamous carcinoma in two cases, and clear-cell adenocarcinoma in one case. There was no evidence of parametrial invasion or lymph node metastases in any patient who had radical surgery, and there were no disease recurrences. CONCLUSION: Patients with microinvasive adenocarcinoma who met criteria for FIGO stage IA1 cervical carcinoma had disease limited to the cervix, and conservative surgery, such as cone biopsy or simple hysterectomy, might offer them definitive treatment. 相似文献
8.
JB Tyrrell KR Lamborn LT Hannegan CB Applebury CB Wilson 《Canadian Metallurgical Quarterly》1999,44(2):254-61; discussion 261-3
OBJECTIVE: Prolactinomas are frequently treated primarily with dopamine agonists; however, these agents have disadvantages and require life-long therapy. We therefore reassessed transsphenoidal microsurgery as an alternative therapy. METHODS: We reviewed the data for 121 female patients treated surgically for prolactinomas between 1976 and 1979 (Group 1) and 98 patients treated between 1988 and 1992 (Group 2). RESULTS: Of 219 women, 92% with preoperative prolactin (PRL) values of < or = 100 ng/ml and 91% with intrasellar microadenomas experienced initial remission; 80 to 88% of patients with intrasellar macroadenomas or macroadenomas showing moderate suprasellar extension or focal sphenoid sinus invasion experienced remission. Women with PRL values of > 200 ng/ml and those with larger and more invasive adenomas experienced poorer outcomes (37-41% remission). Lower preoperative PRL values and adenoma stage were the best predictors of initial surgical outcomes. At the most recent evaluations, 89% of women who experienced initial remission continued to experience clinical remission; 85% exhibited normal PRL values, and 5% demonstrated mild, asymptomatic, recurrent hyperprolactinemia (PRL values of < 34 ng/ml). In Group 1, 84% of patients continued to experience remission (82% with normal PRL values) after a median follow-up period of 15.6 years. In Group 2, 97% of patients continued to experience remission (88% with normal PRL values) after a median follow-up period of 3.2 years. Lower postoperative PRL values were the best predictors of long-term remission. CONCLUSION: Transsphenoidal microsurgery is an effective alternative to long-term medical therapy for selected patients with prolactinomas. Successful outcomes and long-term remission were achieved in patients with microadenomas and noninvasive macroadenomas. 相似文献
9.
Andreas FISSEL Ayan Roy CHAUDHURI Jan KRÜGENER Philipp GRIBISCH H. Jörg OSTEN 《材料科学前沿(英文版)》2015,9(2):141
The step-flow growth condition of Si on Si(111) near the (7×7)-"1×1" surface phase transition temperature TC are analyzed within the framework of Burton--Cabrera--Frank theory. In particular, coexistence of both surface phases well below TC and their specific influence on the step-flow growth behavior are considered. We presume that under dynamical condition of growth, the surface initially covered by only the (7×7) phase separates into domains surrounded by "1×1" areas. On such a surface, the overall supersaturation should be reduced drastically compared to a surface with only (7×7), resulting in much larger critical terrace width for nucleation. 相似文献
10.
Volatile degradation products of zinc dialkyl dithio phosphate (ZDDP) composed of phosphorus and sulfur compounds reduce the
efficiency of catalytic converters resulting in harmful emissions. A unique way of reducing ZDDP level while maintaining good
antiwear performance has been achieved by reacting a novel additive FeF3 with ZDDP. The objective of this research is to examine the chemical interactions between ZDDP and FeF3 that yield the new chemical species responsible for the improved wear performance. The approach adopted involves studies
of thermal degradation products of ZDDP that are formed in presence and absence of FeF3. These intermediate products are responsible for the formation of protective tribofilms on the surface. Nuclear Magnetic
Resonance Spectroscopy (31P and 19F) has been principally used to identify these products. Results have indicated the formation of new fluorinated phosphorus
compounds formed as ‘early intermediate’ products in the reaction between ZDDP and FeF3. The chemical differences observed were used to justify the improved tribological behavior of the new fluorinated ZDDP compounds
in comparison to ZDDP.
Paper was presented at the STLE/ASME International Joint Tribology Conference, October 23–25, 2006, San Antonio, TX. Paper
Number IJTC2006-12053. 相似文献