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51.
We describe a new, real-time, noninvasive method for dis-bond (delamination) detection which is based on a technique known as impulsive stimulated thermal scattering (ISTS). We first explain the ISTS technique and compare data from polyimide films tightly bound to silicon substrates with data from unsupported polyimide films. The observed differences in the data from these two cases are readily understandable and offer an unmistakable signature for delaminations. We demonstrate ISTS dis-bond detection by locating and mapping out randomly-distributed and spatially-fine regions of delamination in a polyimide film-silicon substrate system. Finally, we present two simple physical models of the interfacial region which comprehensively describe acoustic data from the tightly-bound and the unsupported samples. With insight from simulations using these models, we suggest how ISTS might be used to determine interfacial adhesion quality and we show how ISTS sensitivity to interfacial effects can be adjusted. 相似文献
52.
Characterization of the adipose tissue atrophy induced by peroxisome proliferators in mice 总被引:4,自引:0,他引:4
In the present study, we characterized the effects of peroxisome proliferators (PP) on adipose tissue in mice. Treatment with
potent PP, such as perfluorooctanoic acid (PFOA), 2-methyl-2-(p(1,2,3,4-tetrahydroxy-naphthyl)-phenoxy)propionic acid, (4-chloro-6-(2,3-xylidino)2-pyrimidinylthio) acetic acid, and di(2-ethylhexyl)phthalate,
caused dramatic decreases in adipose tissue weight, whereas the moderately potent PP, acetylsalicylic acid, had a relatively
weak effect. This decrease in weight reflects a loss of fat from adipocytes rather than a loss of cells, as demonstrated by
constant DNA content. The dose-dependency and time-course experiments indicate that peroxisome proliferation occurs simultaneously
with or prior to adipose tissue atrophy. Thus, hepatic peroxisome proliferation might result in the increased mobilization
of lipids and lipid utilization in liver. The enhanced adipose tissue hormonesensitive lipase (HSL) activity and down-regulated
lipoprotein lipase (LPL) activity observed upon PP treatment might, at least in part, explain the loss of fat via increase FA release from adipocytes and/or decreased FA uptake from the circulation, respectively. In addition, the possible
involvement of the increased tumor necrosis factor α expression found upon PFOA treatment in reducing the insulin sensitivity
of adipose tissue and thereby altering LPL and HSL activities is discussed. 相似文献
53.
Edward C. Nelson 《应用聚合物科学杂志》1985,30(7):2779-2786
The homogeneous graft copolymerization of acrylamide (AM) onto cellulose initiated by t-butylperoxy-2-ethylhexanoate in a cellulose solvent, N-methylmorpholine oxide (NMMO), was investigated. The method afforded water-soluble PAM-g-cellulose copolymers in fair yields. The copolymers produced are of low molecular weight (50,000–100,000 M?w). Little apparent homopolymerization was observed. 相似文献
54.
Y. B. Che Man L. S. Wei A. I. Nelson N. Yamashita 《Journal of the American Oil Chemists' Society》1991,68(7):471-473
Soaking soybeans in dilute acids affected activities of lipoxygenase, trypsin inhibitor and urease. Effects of soaking time,
acid concentration and soaking temperature were investigated. Lipoxygenase activity was completely eliminated by soaking in
0.3 M HC1 at either 23°C or 40°C for 8 hr. Less than 50% trypsin inhibitor remained and urease was inactivated to an acceptable
level (0.04 ΔpH). 相似文献
55.
K. J. Sternberg L. S. Wei A. I. Nelson 《Journal of the American Oil Chemists' Society》1990,67(5):308-314
Two soybean varieties (Beeson and Williams) were harvested at various maturation levels by applying paraquat directly to the
growing plant. The application of this herbicide to arrest growth was used to simulate freeze damage. The free fatty content
and the photometric index declined from 0.61% to 0.19% and 301.56 to 201.90, respectively, as maturation progressed for the
Beeson variety. Similar trends were found with the Williams variety. However, the amount of trypsin inhibitor differed between
the two varieties depending upon maturation level. 相似文献
56.
The incorporation of inorganic phosphate (as NaH2PO4) into the phospholipids of sheep red blood cells was studied in vitro in blood samples from five highpotassium (HK) and five
low-potassium (LK) sheep. The erythrocytes from HK sheep incorporated more activity in 4 hr than those from the LK sheep.
However no activity was incorporated into the major phospholipids of the cells (phosphatidyl ethanolamine, phosphatidyl serine,
and sphingomyelin) of either group. The phosphatidic acid fraction was labeled in both groups and to a significantly greater
extent in the HK samples. However the highest activity in the phospholipid of sheep red-cells was located in three unknown
compounds not previously detected. Their specific activities were the same in the HK and the LK samples although they were
present in slightly larger amounts in the HK samples. In general, incorporation was at a rather low level, and from stoichiometric
considerations it was concluded that the metabolism in the red-cell phospholipids could not be directly involved in the active
transport of ions across the cell membrane. This work also confirmed a previous report that no quantitative differences exist
among the major phospholipid classes in the two types of cells. 相似文献
57.
Yasmin AlNoamany Ahmed AlSum Michele C. Weigle Michael L. Nelson 《International Journal on Digital Libraries》2014,14(3-4):101-115
The Internet Archive’s (IA) Wayback Machine is the largest and oldest public Web archive and has become a significant repository of our recent history and cultural heritage. Despite its importance, there has been little research about how it is discovered and used. Based on Web access logs, we analyze what users are looking for, why they come to IA, where they come from, and how pages link to IA. We find that users request English pages the most, followed by the European languages. Most human users come to Web archives because they do not find the requested pages on the live Web. About 65 % of the requested archived pages no longer exist on the live Web. We find that more than 82 % of human sessions connect to the Wayback Machine via referrals from other Web sites, while only 15 % of robots have referrers. Most of the links (86 %) from Websites are to individual archived pages at specific points in time, and of those 83 % no longer exist on the live Web. Finally, we find that users who come from search engines browse more pages than users who come from external Web sites. 相似文献
58.
James N. Seiber Paul M. Tuskes Lincoln P. Brower Carolyn J. Nelson 《Journal of chemical ecology》1980,6(2):321-339
Adult monarch butterflies,Danaus plexippus L. (Lepidoptera: Danaidae), store only some of the cardenolides present in the larval milkweed (Asclepiadaceae) host. Feeding known doses of individual cardenolides to 4th instar monarch larvae led to more efficient larval tissue incorporation at low doses than at high ones, and favored storage of cardenolide glycosides over genins. A qualitative regulation also occurs during larval feeding; calactin and calotropin were stored as such but uscharidin was rapidly converted to a mixture of calactin and calotropin which were the forms stored by the larvae. Two genins, uzarigenin and digitoxigenin, were stored by larvae as polar cardenolide metabolites.Research supported by National Science Foundation grants DEB 7514266 and DEB 7514266-AO2 (U.C. Davis) and DEB 7514265 (Amherst College). 相似文献
59.
Stephen Scypinski Linda Nelson Theodore Sadlowski 《Journal of Automated Methods and Management in Chemistry》1995,17(2):47-49
It has been over 10 years since robots have appeared in the pharmaceutical analysis laboratory. In the early days, it was common for one selected individual to be responsible for the programming, usage and maintenance of the robots(s). However, the increasing use of robotics has prompted the formation of robotics
‘laboratories’ and/or ‘groups’. This is especially true when
multiple robotic systems and applications are involved.Over the past several years at ISLAR, many champions of robotics have given presentations on the setup and usage of robotics within their organizations. These managers have described both the ‘centralized’ and ‘decentralized’ approaches to the implementation of robotics. In the centralized system, a single group is charged with all aspects of the robotic project, including justification, purchase, validation, use and maintenance. Under such an
arrangement, samples are usually given to the robotics group for analysis. In contrast, a totally decentralized approach to robotics would have units interspersed throughout the organization, with each individual group responsible for their respective unit(s), in
much the same way as liquid chromatographs are considered.At Hoffmann-La Roche, aspects of both the centralized and decentralized approaches to robotics are used which make our combined system the ‘best of both worlds’. This paper describes the Roche philosophy towards robotics and highlights the advantages to the system used. 相似文献
60.
Alaa?S.?Abd-El-AzizEmail author Nelson?M.?Pereira Waleed?Boraie Erin?K.?Todd Tarek?H.?Afifi Wes?R.?Budakowski Ken?J.?Friesen 《Journal of Inorganic and Organometallic Polymers and Materials》2005,15(4):497-509
The synthesis of the title complexes was achieved via the reaction of
-p-dichlorobenzene-
-cyclopentadienyliron cations with 4,4′-bis(4-hydroxyphenyl)valeric acid to produce the diiron complexes which were then reacted with a number of arylazo dyes to give cationic bis(cyclopentadienyliron)arene complexes containing the arylazo dyes. These iron-containing monomers were subsequently polymerized via nucleophilic aromatic substitution using 1,8-octanedithiol, 4,4′-thiobisbenzenethiol, or bisphenol A to produce the desired coloured cationic organoiron polymers. The weight – average molecular weights were estimated to range from 11,800 to 31,600. UV–vis studies conducted in dimethylformamide (DMF) showed that the metallated polymers exhibited
of 412–491 nm. Addition of HCl to the polymer solution caused a bathochromic shift into the range of 515–530 nm. Thermogravimetric analysis (TGA) revealed that the iron moieties were cleaved between 205 and 248 °C while the polyether/thioether backbone degraded between 380 and 613 °C. Differential scanning calorimetry (DSC) showed that the polymers exhibited glass transition temperatures (Tg) ranging from 106 to 184°C.This paper is dedicated to Professor Richard J. Puddephatt in recognition of his outstanding contribution to the field of metal-containing polymers. 相似文献