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981.
MA Nalesnik AS Rao H Furukawa S Pham A Zeevi JJ Fung G Klein HA Gritsch E Elder TL Whiteside TE Starzl 《Canadian Metallurgical Quarterly》1997,63(9):1200-1205
Lymphoreticular malignancies, collectively called posttransplant lymphoproliferative disorders (PTLD), eventually develop in 2-5% of organ transplant recipients. They frequently undergo regression when immunosuppression is reduced or stopped. This feature has been associated with a previous or de novo Epstein-Barr virus (EBV) infection. We herein describe immunotherapy with autologous lymphokine-activated killer (LAK) cells in seven patients with PTLD (four EBV-positive patients and three EBV-negative patients). Autologous peripheral blood mononuclear cells were obtained by leukapheresis, depleted of monocytes, and cultured in the presence of interleukin 2 for 10 to 11 days. A single dose of 5.2 x 10(9) to 5.6 x 10(10) LAK cells was given intravenously. Systemic interleukin 2 was not administered. The four patients with EBV+ PTLD had complete tumor regression; two of them developed controllable rejection. Three patients are well 13-16 months after treatment; the fourth patient died of pneumonia 41 days after infusion. Three patients with EBV- lymphomas had no response despite prior evidence that their tumors also were subject to immune surveillance. Two of these three patients died after being given other treatment, and the third patient has persistent tumor. In conclusion, autologous LAK cell infusion was effective for treatment of four EBV+ organ transplant recipients. LAK cell efficacy for three patients with EBV- PTLD was not evaluable under the management circumstances in which this treatment was utilized. 相似文献
982.
983.
A. Srinivasa Rao J. Lakshmana Rao R. Ramakrishna Reddy T. V. Ramakrishna Rao 《Optical Materials》1995,4(6):717-721
The Electron Paramagnetic Resonance (EPR) spectrum at 9.205 GHz and at 300 K has been examined for a series of Cr3+ ions doped alkali cadmium borosulphate [R2SO4-CdSO4-B2O3 (R=Li,Na,K or Cs)] glasses. The low field EPR spectral resonance lines are attributed to isolated Cr3+ ions where as the high field spectral resonance lines are attributed to exchange coupled pairs of Cr3+ ions. The absorption spectra of Cr3+ ions ions in these glasses show two broad bands characteristic of Cr3+ ions in octahedral symmetry. The bands are slightly shifted to higher wavelength side from Li glass to Cs glass. From the optical spectra the crystal field parameter Dq and the Racah interelectronic repulsion parameters B and C are evaluated. From the EPR and optical data, it is concluded that, the site symmetry around the Cr3+ ions is octahedral and the nature of bonding is predominantly covalent in nature. 相似文献
984.
Considerations in estimating Nitrogen Recovery Efficiency by the difference and isotopic dilution methods 总被引:3,自引:0,他引:3
A. C. S. Rao J. L. Smith J. F. Parr R. I. Papendick 《Nutrient Cycling in Agroecosystems》1992,33(3):209-217
Nitrogen Recovery Efficiencies (NRE) as calculated by the Isotopic dilution technique or the difference method are subject to errors under different conditions. The assumptions underlying these methods and the conditions and factors that must be considered while using these methods have been discussed. Majority of the reports suggest that the difference method gives higher values than the isotopic dilution technique. Results of a pot experiment show the importance of accounting the N held in roots for estimating NRE by either of the methods. Although the isotopic dilution technique has been invariably more precise, it was not necessarily representing the true NRE value. Contrary to some earlier reports, it was observed that Added Nitrogen Interaction (ANI) occurred even in field experiments. Guidelines are provided to assist researchers in assessing the validity of using isotopic or difference method in a given situation. For conditions where the NRE values obtained by either of the methods are influenced by ANI, a method of correcting the NRE values has been suggested, to arrive at the most probable value. 相似文献
985.
AIM: Appendiceal air has been reported as both a sign of appendicitis and of a normal appendix both at plain radiography and computed tomography (CT). It is the aim of this investigation to determine the prevalence, range of appearances, and significance of appendiceal and peri-appendiceal air at CT. PATIENTS AND METHODS: Appendiceal CT scans of 100 patients with proven appendicitis and 100 patients with a normal appendix were reviewed for the presence of appendiceal and peri-appendiceal air. All cases were correlated with surgical and pathological findings or clinical follow-up. RESULTS: In 100 CT cases of appendicitis, appendiceal and/or peri-appendiceal air was present in one or more forms in 31% of cases. When present, it appeared as intraluminal air bubbles (38.7%) or air-fluid levels (22.6%), appendolith air (41.9%), intramural air (16.1%), peri-appendiceal air bubbles (12.9%), or extraluminal air-fluid level(s) (29.0%). Intramural and extraluminal air correlated with perforation in 60% and 100%, respectively. In 100 CT cases of a normal appendix, air was present in 57%. It was always intraluminal and appeared as small bubbles of air (52.6%), a tubular-shaped air collection (43.9%), or as an air-fluid level (3.5%). The appendiceal lumen was either airless (43%), or minimally (32%), moderately (18%), or completely filled with air (7%). CONCLUSION: Air is a common finding at appendiceal CT in both the normal and inflamed appendix. Intraluminal air is seen in both appendicitis and normal appendices, and cannot be presumed to indicate a patent lumen and thus a normal appendix. Appendolith, intramural and peri-appendiceal air appear diagnostic of appendicitis. 相似文献
986.
K. Bhanu Sankara Rao M. G. Castelli G. P. Allen John R. Ellis 《Metallurgical and Materials Transactions A》1997,28(2):347-361
The low-cycle fatigue (LCF) behavior of a wrought cobalt-base superalloy, Haynes 188, has been investigated over a range of
temperatures between 25 °C and 1000 °C employing a triangular waveform and a constant strain amplitude of ±0.4 pct. Correlations
between macroscopic cyclic deformation and fatigue life with the various microstructural phenomena were enabled through scanning
electron microscopy (SEM) and transmission electron microscopy (TEM), detailing the crack initiation and propagation modes,
deformation substructure, and carbide precipitation. Cyclic stress response varied as a complex function of temperature. Dynamic
strain aging (DSA) was found to occur over a wide temperature range between 300 °C and 750 °C. In the DSA domain, the alloy
exhibited marked cyclic hardening with a pronounced maximum at 650 °C. Dynamic strain aging has been documented through the
occurrence of serrated yielding, inverse temperature dependence of maximum cyclic stress, and cyclic inelastic strain developed
at half of the fatigue life. Additionally, the alloy also displayed a negative strain rate sensitivity of cyclic stress in
the DSA regime. These macroscopic features in the DSA domain were accompanied by the substructure comprised of coplanar distribution
of dislocations associated with the formation of pileups, stacking faults, and very high dislocation density. Toward the end
of the DSA domain, dislocation pinning by M23C6 precipitates occurred predominantly. The deformation behavior below and above the DSA domain has also been investigated in
detail. The temperature dependence of LCF life showed a maximum at ≈300 °C. The drastic reduction in life between 300 °C and
850 °C has been ascribed primarily to the deleterious effects of DSA on crack initiation and propagation, while the lower
life at temperatures less than 200 °C has been attributed to the combined influence of low ductility and larger cyclic response
stress. 相似文献
987.
Ion implantation of Si in semi-insulating In0.53Ga0.47As:Fe was discussed. Electrical activation of more than 100%, a broad implant profile and an average electron mobility of 3000 cm2/Vs are observed in layers implanted with a dose of 2 × 1013 cm?2 at 260 keV and annealed at 670°C for 15 min. The results of photoluminescence measurements are also presented. 相似文献
988.
A novel, miniaturized high-throughput screening format is described for assay of combinatorial libraries generated on beads. This approach, which is ideally suited to encoded libraries synthesized on beads, utilizes the photolytic cleavage of individual compounds into a high-density well array (>6500 wells within a standard 96-well microtiter plate footprint) with well volumes as low as 0.37 microl. As a model study, an encoded dipeptide library (324 members) acylated with isobutyl succinate was assayed using this format to search for potential inhibitors of matrilysin, a member of the matrix metalloproteinase superfamily. In situ release of compounds from solid support was accomplished by photochemical cleavage after beads and enzyme were distributed to the wells. After the addition of a fluorogenic substrate to the array, the extent of enzyme inhibition and identification of active compounds was quantitated by imaging of the fluorescence emission upon uv irradiation. The structure-activity relationship data generated from the identified inhibitors in this study corroborate previous findings, thus validating the utility of this approach as a means of high-throughput screening of bead-based libraries. 相似文献
989.
Immunization by peptides based on the repeat sequences of Plasmodium falciparum or P. vivax antigen(s) have shown inconsistent results during clinical trials in humans. This could be attributed to the lack of T-cell help or antigenic polymorphism. Thus, attention has been focused towards the more conserved non-repeat regions. The present study was undertaken to map the antigenic determinant in the vicinity of region II (outside the repeat) of CS protein of P. vivax. The immunogenicity of the peptide was studied alone and after linking with polytuftsin (PT), using alum and Freund's adjuvant, in inbred strains of mice with different genetic backgrounds. The humoral response and antigen induced T-cell proliferation assays clearly demonstrated the immunomodulatory activity of PT. Comparable results were observed with antigen(s) administered either in alum or Freund's adjuvant. The induction of IgG2a and IgG2b antibody isotypes by both, peptide as well as the conjugate, may indicate that the T-helper response involved is of Th1 type. Further the immunofluorescence studies have shown that antibodies recognized the air dried sporozoites of P. cynomolgi. The results thus show that the above sequence has overlapping B and T-cell determinants and that alum can be substituted for Freund's adjuvant in generating an effective immune response. 相似文献
990.