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91.
Nikolaus Weber 《Lipids》1988,23(1):42-47
[4-14C]Sitosteryl β-D-glucoside, intragastrically administered to rats, was not absorbed by the intestinal mucosa. At three hr
after the application, radioactivity was concentrated almost exclusively in the digesta of stomach, small intestine as well
as cecum and colon, whereas only low proportions of radioactively labeled compounds were found in the various tissues of the
gastrointestinal tract. Minor proportions of labeled metabolites of [4-14C]sitosteryl β-D-glucoside, such as sitosterol and sitosteryl esters, were formed in the small intestine in vivo and in slices
of small intestine in vitro. In the tissues of cecum and colon as well as the digesta derived from them, high proportions
of labeled coprositostanol, i.e. 24α-ethyl-5β-cholestan-3β-ol, that obviously had been formed by bacterial degradation of
the substrate were detected.
The feeding of sitosteryl β-D-glucoside (0.5 g/kg body weight×day) over a period of four weeks did not alter significantly
body weights or organ weights of rats. Analyses of steryl lipids of the various organs and tissues confirmed the findings
obtained with the radioactive substrate: neither sitosteryl β-D-glucoside nor sitosterol or sitosteryl esters derived therefrom
had been transported in appreciable amounts to organs and tissues outside the alimentary canal during the feeding period.
Minor proportions of unmetabolized sitosteryl β-D-glucoside were detected in the tissues of stomach and intestine, whereas
large proportions of the substrate were found in feces of rats that had received the sitosteryl β-D-glucoside-containing diet;
coprositostanol was found in feces of these animals in high proportions as well. Thus, the use of sitosteryl β-D-glucoside
as emulsifier or preservative in food and feed does not appear to involve any risk.
The systematic nomenclature of the sterols referred to by trivial names is, cholest-5-en-3β-ol (cholesterol); 5α-cholestan-3β-ol
(5α-cholestanol); 5β-cholestan-3β-ol (5β-cholestanol, coprostanol); 24α-methylcholest-5-en-3β-ol (campesterol); 24α-methyl-5α-cholestan-3β-ol
(5α-campestanol); 24α-methyl-5β-cholestan-3β-ol (5β-campestanol, coprocampestanol); 24α-methyl-cholesta-5,22-dien-3β-ol (brassicasterol);
24α-ethylcholest-5-en-3β-ol (sitosterol, β-sitosterol); 24α-ethyl-5α-cholestan-3β-ol (5α-sitostanol); 24α-ethyl-5β-cholestan-3β-cholestan-3β-ol
(5β-sitostanol, coprositostanol); 24α-ethylcholesta-5,22-dien-3β-ol (stigmasterol). 相似文献
92.
93.
We present an approach for extracting extremal feature lines of scalar indicators on surface meshes, based on discrete Morse Theory. By computing initial Morse‐Smale complexes of the scalar indicators of the mesh, we obtain a candidate set of extremal feature lines of the surface. A hierarchy of Morse‐Smale complexes is computed by prioritizing feature lines according to a novel criterion and applying a cancellation procedure that allows us to select the most significant lines. Given the scalar indicators on the vertices of the mesh, the presented feature line extraction scheme is interpolation free and needs no derivative estimates. The technique is insensitive to noise and depends only on one parameter: the feature significance. We use the technique to extract surface features yielding impressive, non photorealistic images. 相似文献
94.
J.J. Sharples R.H.D. McRae R.O. Weber A.M. Gill 《Environmental Modelling & Software》2009,24(5):637-646
Assessing fuel moisture content to within a reasonable degree of accuracy is an important part of wildland fire management. In this paper we introduce a fuel moisture index that provides a simple and intuitive method for assessing fuel moisture content. The method can be quickly and easily applied in a field setting to provide a dimensionless measure of fuel moisture content. We compare the index with predictions from several models for fuel moisture content and conclude that it provides an equivalent measure of fuel moisture content for a number of fuel types. We go on to briefly discuss how the index could be used to construct a simple and intuitive fire danger index. 相似文献
95.
J.J. Sharples R.H.D. McRae R.O. Weber A.M. Gill 《Environmental Modelling & Software》2009,24(6):764-774
Fire danger rating systems are used to assess the potential for bushfire occurrence, fire spread and difficulty of fire suppression. Typically, fire danger rating systems combine meteorological information with estimates of the moisture content of the fuel to produce a fire danger index. Fire danger indices are used to declare fire bans and to schedule prescribed burns, among other applications. In this paper a simple fire danger index F that is intuitive and easy to calculate is introduced and compared to a number of fire danger indices pertaining to different fuel types that are used in an operational setting in Australia and the United States. The comparisons suggest that F provides a plausible measure of fire danger rating and that it may be a useful pedagogical tool in the context of fire danger and fire weather. 相似文献
96.
Jan-Patrick Elsholz Guido de Melo Marc Hermann Michael Weber 《Pervasive and Mobile Computing》2009,5(5):592-605
Ambient displays provide us with information in the background of our awareness. However, as each user has individual wishes and needs of how, which and when information is presented, the acceptance of ambient displays is low.In this paper we introduce an extensible architecture for personalized ambient information.We employ a notification system to extend the capability of a fixture to display more than one variable. Multiple variables can be updated by multiple information providers. Thereby, our architecture covers a broader spectrum of notifications from alarms to ambient information.We evaluate our concept within a dual-task experiment in comparison to preset notifications. The results show a level of self-interruption which is significantly lower than using preset notifications. Therefore our approach outperforms preset notifications and moves ambient displays closer to secondary displays in human–computer interaction. 相似文献
97.
Jastorff AM Haegler K Maccarrone G Holsboer F Weber F Ziemssen T Turck CW 《Proteomics. Clinical applications》2009,3(11):1273-1287
Multiple sclerosis is characterized by inflammatory demyelination and axonal loss as pathophysiological correlates of relapsing activity and progressive development of clinical disability. The molecular processes involved in this pathogenesis are still unclear as they are quite complex and heterogeneous. In this article we present protein expression analysis of brain and spinal cord tissues from different models of murine experimental autoimmune encephalomyelitis (EAE), the most commonly used animal model for multiple sclerosis. We observed a number of EAE-specific protein expression and PTM differences. Proteome analysis was extended to multiple sclerosis specimens in order to validate the EAE findings. Our findings suggest the regulation of a number of proteins that shed light on the molecular mechanisms of the disease processes taking place in EAE and multiple sclerosis. We found consistent modulation of proteins including serum amyloid P component, sirtuin 2, dihydropyrimidinase-related protein family proteins, stathmin 1, creatine kinase B and chloride intracellular channel protein 1. Functional classification of the proteins by database and the literature mining reveals their association with neuronal development and myelinogenesis, suggesting possible disease processes that mediate neurodegeneration. 相似文献
98.
Estimating the virial coefficients of small polar molecules 总被引:2,自引:0,他引:2
We adapt existing models for estimating the second and third virial coefficients of small molecules to the halogenated methanes and ethanes. We compare the results with the abundant new, high-qualityPVT data resulting from the search for alternative refrigerants. The present model provides an accurate method for calculating densities, and therefore it should provide reliable thermodynamic properties and fugacity coefficients. We give equations and parameters useful for estimating the properties of pure refrigerants and their mixtures when noPVT data are available.Nomenclature
B
Second virial coeficient
-
B
12
Mixture cross second virial
-
B
h
Second virial of a hard sphere fluid
-
i
(T)
Temperature function, second virial, Eq. (7)
-
C
Third virial coefficient
-
C
112,C
122
Mixture cross third virials
-
C
h
Third virial of a hard sphere fluid
-
N
Avogadro's number
Virial Coefficients
P
c
Critical pressure
-
P
c12
Characteristic critical pressure of a binary mixture
-
T
c
Critical temperature
-
T
c12
Characteristic critical temperature of a binary mixture
-
T
r
Reduced temperature,T/T
c
-
Parameter measuring polar contribution toB, Eq. (3)
-
b
Volume of a hard sphere molecule
-
f
(f)
Polynomials determining temperature dependence of the nonpolar part ofB
-
k
12
Binary interaction parameter for mixtures, Eq. (9a)
-
c
Critical volume
-
e
Molecular polarizability
-
Dipole moment
-
R
Reduced dipole moment, Eq. (4)
-
R12
Mixture reduced dipole moment, second virial
-
R112,
R122
Mixture reduced dipole moment, third virial
-
Pitzer acentric factor
-
12
Mixture acentric factor
-
(r)
Intermolecular potential
-
c
Critical density (1/c) 相似文献
99.
100.
Jian-Qing Lu Rabah Boukherroub Georges Manuel William P. Weber 《Journal of Inorganic and Organometallic Polymers》1995,5(1):61-74
Poly[1-methyl-1-[3-(3-pyridinyl)propyl]-1-sila-cis-pent-3-ene], poly[1-phenyl-1-[3-(3-pyridinyl)propyl)-1-sila-cis-pent-3-ene], and poly[1-phenyl-1-(4-pyridinyl)-1-sila-cis-pent-3-ene] were synthesized by the anionic ring-opening polymerization of 1-methyl-1-[3-(3-pyridinyl)propyl]-1-silacyclopent-3-ene, 1-phenyl-1-[3-(3-pyridinyl)propyl]-1-silacyclopent-3-ene, and 1-phenyl-1-(4-pyridinyl)-1-silacyclopent-3-ene, respectively. These are the first polycarbosilanes which contain heterocyclic pyridine units as side-chain substituents. These polymers were characterized by1H,13C, and29Si NMR as well as by IR and UV spectroscopy. The molecular weight distributions were determined by gel permeation chromatography, glass transition temperatures, by differential seanning calorimetry: (DSC) and thermal behavior, by thermogravimetric analysis. (TGA). 相似文献