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81.
Inherent and apparent scattering properties of coated or uncoated spheres embedded in an absorbing host medium 总被引:1,自引:0,他引:1
Yang P Gao BC Wiscombe WJ Mishchenko MI Platnick SE Huang HL Baum BA Hu YX Winker DM Tsay SC Park SK 《Applied optics》2002,41(15):2740-2759
The conventional Lorenz-Mie formalism is extended to the case for a coated sphere embedded in an absorbing medium. The apparent and inherent scattering cross sections of a particle, derived from the far field and near field, respectively, are different if the host medium is absorptive. The effect of absorption within the host medium on the phase-matrix elements associated with polarization depends on the dielectric properties of the scattering particle. For the specific cases of a soot particle coated with a water layer and an ice sphere containing an air bubble, the phase-matrix elements -P12/P11 and P33/P11 are unique if the shell is thin. The radiative transfer equation for a multidisperse particle system embedded within an absorbing medium is discussed. Conventional multiple-scattering computational algorithms can be applied if scaled apparent single-scattering properties are applied. 相似文献
82.
Radiometric correction of multi-temporal Landsat data for characterization of early successional forest patterns in western Oregon 总被引:2,自引:0,他引:2
Detecting and characterizing continuous changes in early forest succession using multi-temporal satellite imagery requires atmospheric correction procedures that are both operationally reliable, and that result in comparable units (e.g., surface reflectance). This paper presents a comparison of five atmospheric correction methods (2 relative, 3 absolute) used to correct a nearly continuous 20-year Landsat TM/ETM+ image data set (19-images) covering western Oregon (path/row 46/29). In theory, full absolute correction of individual images in a time-series should effectively minimize atmospheric effects resulting in a series of images that appears more similar in spectral response than the same set of uncorrected images. Contradicting this theory, evidence is presented that demonstrates how absolute correction methods such as Second Simulation of the Satellite Signal in the Solar Spectrum (6 s), Modified Dense Dark Vegetation (MDDV), and Dark Object Subtraction (DOS) actually make images in a time-series somewhat less spectrally similar to one another. Since the development of meaningful spectral reflectance trajectories is more dependant on consistent measurement of surface reflectance rather than on accurate estimation of true surface reflectance, correction using image pairs is also tested. The relative methods tested are variants of an approach referred to as “absolute-normalization”, which matches images in a time-series to an atmospherically corrected reference image using pseudo-invariant features and reduced major axis (RMA) regression. An advantage of “absolute-normalization” is that all images in the time-series are converted to units of surface reflectance while simultaneously being corrected for atmospheric effects. Of the two relative correction methods used for “absolute-normalization”, the first employed an automated ordination algorithm called multivariate alteration detection (MAD) to statistically locate pseudo-invariant pixels between each subject and reference image, while the second used analyst selected pseudo-invariant features (PIF) common to the entire image set. Overall, relative correction employed in the “absolute-normalization” context produced the most consistent temporal reflectance response, with the automated MAD algorithm performing equally as well as the handpicked PIFs. Although both relative methods performed nearly equally in terms of observed errors, several reasons emerged for preferring the MAD algorithm. The paper concludes by demonstrating how “absolute-normalization” improves (i.e., reduces scatter in) spectral reflectance trajectory models used for characterizing patterns of early forest succession. 相似文献
83.
Warren L. Baker 《Journal of the Institute of Brewing》1991,97(6):457-462
An enzymic method has been developed for analysis of glucose. Glucose oxidase acts on glucose to produce hydrogen peroxide which acts to directly reduce the green Cu(II) 2–2′-bicinchoninate complex to a violet complex without horseradish peroxidase. A concentration range of 20–200 μM glucose was used but the reaction shows a linear range of 20–800 μM glucose. Interference is controlled by using a blank determination which has not been treated with glucose oxidase. The reaction has been used to estimate glucose levels in Saccharomyces cerevisiae fermentation and α-amylase, invertase and β-galactosidase reactions and coloured corn-steep fermentation media. 相似文献
84.
KJ Warren 《Canadian Metallurgical Quarterly》1998,61(6):329-334
This article summarise the main data in the literature on the role of bacteriological contamination of the dialysate fluid in inflammatory reactions in hemodialysis. Pyrogenic substances of small molecular weight from Gram-negative bacteria grown in dialysate can pass across intact dialyzer membrane to stimulate cytokine production by peripheral blood mononuclear cells. Cellulosic hemodialysis membranes are more permeable to endotoxins than synthetic membranes. Polysulfone membranes and polyamide membranes are able to adsorb bacterial toxins on the dialysate side. The diffusive transfer of bacterial products across dialysis membrane from dialysate fluid was demonstrated. Transmembrane passage of cytokine-inducing bacterial products across reprocessed dialyzers is greater than across new dialyzers. Bacteriological contamination of the dialysate fluid is a problem which must be considered with much more care by nephrologists, especially as LAL test is unable to detect all the bacterial products which can contaminate the dialysate fluid. 相似文献
85.
GN Schwartz MK Warren SW Rothwell J Zujewski DC Halverson KH Cowan A Tolcher J O'Shaughnessy RE Gress 《Canadian Metallurgical Quarterly》1998,22(5):457-468
Marrow stromal layers were used to investigate the potential role of negative regulators produced by the marrow microenvironment as one potential cause of hematopoietic suppression after chemotherapy and cytokines. Stromal layers were established from marrow of normal or prechemotherapy donors and breast cancer patients after hematological recovery from one cycle of 5-fluorouracil, leucovorin, doxorubicin, and cyclophosphamide and GM-CSF or PIXY321 (GM-CSF/IL-3 fusion protein). Normal donor CD34+ cells were placed in contact with stromal layers, and the number of colony-forming units for granulocytes and macrophages (CFU-GM) was determined. There were 25-79% fewer CFU-GM in post-chemotherapy stromal layer cocultures than in no chemotherapy cocultures. With neutralizing antibody to TNF-alpha the number of CFU-GM in no chemotherapy and post-chemotherapy stromal cocultures was, respectively, 96 +/- 7% (n = 5) and 142 +/- 8% (n = 5) of the number with no antibody treatment. PIXY321 and GM-CSF pretreated stromal layers also suppressed production of CFU-GM. Anti-TNF-alpha promoted an increase in CFU-GM numbers from GM-CSF, but not PIXY321, pretreated stromal cocultures. The results demonstrate that post-chemotherapy marrow stromal layers were deficient in supporting in vitro hematopoiesis and suggest that negative regulators induced by chemotherapy and cytokines may be one cause for this defect. 相似文献
86.
Assouline Z.; Shen H.; Kilburn D.G.; Warren R.A.J. 《Protein engineering, design & selection : PEDS》1993,6(7):787-792
A fusion protein, FXCBDCex, which comprises factor Xwith a cellulose-binding domain (CBDCex) fused to its C-terminus,was produced in BHK cells. It was purified from the culturemedium by affinity chromatography on cellulose. FXCBDCexcould be activated to FXaCBDCex with Russell viper venom.FXaCBDCex was as active as FXa against a chromogenicsubstrate and against proteins containing the IleGluGlyArgsequence hydrolysed by FXa. FXaCBDCex retained its activitywhen adsorbed to cellulose. 相似文献
87.
Depression is a significant problem in epilepsy. Suicides occur in epileptic patients five times more often than in general population. Material included 34 epileptics with 76 suicidal attempts and 24 patients with no history of suicide. Psychical state was studied with Beck Depression Inventory and Hamilton Depression Rating Scale. In the group with suicidal attempts 65% of patients had depression (54.5% of them had major depression) and in group without suicide attempts depression was noted in 54% (23% with major depression). Patients with depression were divided into two groups: group I with suicidal attempts and group II without history of suicide. In group I more patients were alcohol abusers (50% vs 31%), more were treated because of epilepsy longer than 10 years (59% vs 46%) and more had tonic-clonic seizures (82% vs 46%). In group I, 54% of patients were on polytherapy (more than half of them with fenobarbital). In group II, 31% of epileptics were on polytherapy (no one with fenobarbital). Major depression was significantly more frequent in epileptics with suicidal attempts. The severity of depression may influence the risk of suicide. Major depression may be associated with late age of onset of epilepsy, longer treatment duration, tonic-clonic seizures, polytherapy (mainly with fenobarbital) and alcohol abuse. 相似文献
88.
F. F. Feitosa Teles J. Warren Stull William H. Brown Frank M. Whiting 《Journal of the science of food and agriculture》1984,35(4):421-425
The amino acids of prickly pear (Opuntia ficus indica L.) proteins, free amino acids and nonvolatile organic acids were determined on fresh and lyophilised young pads. The calculated biological value of prickly pear protein was 72.6, relative to egg protein. Trace amounts of malonic, malic and citric acids in material collected at 1800 hours; traces 0.95 and 0.31 mg g?1, respectively. In similar material analysed at 0600 hours, the concentrations of those acids were 0.36, 9.85, and 1.78 mg g?1, respectively. Since there was a significant accumulation of the acids during the evening, crassulacean-type metabolism is suggested. 相似文献
89.
BACKGROUND: Topical antimicrobials have been considered for treatment of secondarily infected wounds because of the potential for reduced risk of adverse effects and greater patient convenience. We compared mupirocin cream with oral cephalexin in the treatment of wounds such as small lacerations, abrasions, or sutured wounds. METHODS: In 2 identical randomized double-blind studies, 706 patients with secondarily infected wounds (small lacerations, abrasions, or sutured wounds) received either mupirocin cream topically 3 times daily or cephalexin orally 4 times daily for 10 days. RESULTS: Clinical success at follow-up was equivalent in the two groups: 95.1% and 95.3% in the mupirocin cream and the cephalexin groups, respectively (95% confidence interval [CI], -4.0% to 3.6%; P = .89). The intention-to-treat success rate was 83% in both groups. Bacteriologic success at follow-up was also comparable: 96.9% in the mupirocin cream and 98.9% in the cephalexin groups (95% CI, -6.0% to 2.0%; P = .22). The occurrence of adverse experiences related to study treatment was similar for the 2 groups, with fewer patients in the mupirocin cream group reporting diarrhea (1.1% vs 2.3% for cephalexin). CONCLUSIONS: Mupirocin cream applied topically 3 times daily is as effective as oral cephalexin given 4 times daily for the treatment of secondarily infected wounds and was well tolerated. 相似文献
90.
K Warren E Goldstein VS Hung JE Koehler W Richardson 《Canadian Metallurgical Quarterly》1998,116(7):937-940
A patient with the acquired immunodeficiency syndrome developed bilateral retinitis due to a Bartonella (formerly Rochalimaea) henselae infection. A retinal biopsy was performed when severe and progressive retinal infection failed to respond to empirical treatment for cytomegalovirus and Toxoplasma gondii. The biopsy specimen was stained with routine histopathological stains and the Steiner silver stain. Ribosomal DNA was extracted from formalinfixed, paraffin-embedded retinal tissue and amplified with the polymerase chain reaction assay, using Bartonella-specific primers. The amplified DNA fragment was cloned and sequenced. Staining with hematoxylin-eosin revealed tufts of proliferating vascular endothelium with numerous fusiformappearing cells, consistent with a diagnosis of bacillary angiomatosis. A Steiner silver stain revealed numerous small bacilli in the biopsy specimen. Amplification of DNA extracted from the tissue produced a fragment of 16S ribosomal DNA of the expected size; sequencing of the DNA fragment revealed that the infection was caused by B henselae. The retinal infection was treated with minocycline, doxycycline, and ciprofloxacin with improvement in visual acuity in the ensuing 12 weeks. To our knowledge, this is the first human immunodeficiency virus-infected patient with retinitis due to B henselae who was diagnosed by the identification of silver-staining bacilli and amplification and sequencing of B henselae with a polymerase chain reaction assay using a biopsy specimen of retinal tissue. Retinal biopsy is indicated, despite its potential for serious complications, in patients with acquired immunodeficiency syndrome who have a progressive, sight-threatening retinitis that is undiagnosed and unresponsive to therapy. 相似文献