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1.
Ponnusamy Nandha Kumar Shangavi Subramanian Uthirapathy Vijayalakshmi Sanjeevi Kannan 《Journal of the American Ceramic Society》2020,103(6):3528-3540
Structurally stable β-Ca3(PO4)2/t-ZrO2 composite mixtures with the aid of Dy3+ stabilizer were accomplished at 1500°C. The precursors comprising Ca2+, P5+, Zr4+, and Dy3+ have been varied to obtain five different combinations. The results revealed the fact that complete phase transformation of calcium-deficient apatite to β-Ca3(PO4)2 occurred only at 1300°C, whereas the evidence of t-ZrO2 crystallization is obvious at 900°C. The dual occupancy of Dy3+ at β-Ca3(PO4)2 and t-ZrO2 structures was evident; however, Dy3+ initially prefers to occupy β-Ca3(PO4)2 lattice until its saturation limit and thereafter accommodates at the lattice site of ZrO2. The typical absorption and emission behavior of Dy3+ were noticed in all the systems and, moreover, the surrounding symmetry of Dy3+ domains has been determined from the luminescence study. All the systems ensured paramagnetic response that is generally contributed by the presence of Dy3+. A gradual increment in the phase content of t-ZrO2 in the composite mixtures ensured a significant improvement in the hardness and Young's modulus of the investigated compositions. 相似文献
2.
Kannan Srinivasagam 《电子设计技术》2004,11(2):112-112,114
数据通信和便携式系统成为当今SRAM的重要应用领域.某些SRAM由于能够提供实现较高带宽所需的性能(比如在网络系统中)或维持较长电池使用寿命所需的低功耗(比如在便携式设备中)而在许多应用中起着主导作用. 相似文献
3.
OA al-Swayeh MS al-Humayyd AA Mustafa AS al-Tuwaijri RS al-Rashed AT Ali 《Canadian Metallurgical Quarterly》1997,12(7):481-489
Recent evidence suggests that oxygen-derived free radicals are involved in mediating gastric microvascular and parenchymal cell injuries induced by ischaemia and reperfusion. Therefore, the effect of the locally acting anti-ulcer drug, sucralfate, was studied on ischaemia and reperfusion (e.g. induced gastric lesions, intraluminal bleeding, changes in vascular permeability and non-protein sulfhydryl levels in the rat stomach). Allopurinol was used as a known standard antioxidant drug. Rats were subjected to 30 min of gastric ischaemia in the presence of 100 mmol/L hydrochloric acid and reperfusion periods of 15, 30 or 60 min duration. The gastric lesions were assessed microscopically under an inverted microscope. The vascular permeability was quantified by measuring the extravasated Evans blue in the stomach. There were significantly greater numbers of gastric lesions, intraluminal bleeding and leakage of Evans blue during all reperfusion periods as compared with those of ischaemia, with maximum effects occurring at 60 min following reperfusion. Pretreatment with sucralfate (31.25-250 mg/kg, p.o.) or allopurinol (12.5-50 mg/kg, i.p.) 30 min before the procedure, dose-dependently reduced the gastric lesions, intraluminal bleeding, and decreased the vascular permeability induced by ischaemia and reperfusion. Furthermore, sucralfate dose-dependently reverses the ischaemia and reperfusion-induced depletion of mucosal non-protein sulfhydryl levels and inhibited the superoxide radical production in both cell-free xanthine-xanthine oxidase and in the stimulated polymorphonuclear cellular systems. These results suggest that the protection produced by sucralfate against gastric injury may be due to its antioxidant effects. 相似文献
4.
5.
The tet(M) genes were characterized from 84 isolates of 10 different bacterial species isolated from the periodontal pockets of 16 patients with periodontal disease. A 740 bp polymerase chain reaction product from the hypervariable region of the tet(M) structural gene was cleaved with the restriction enzymes AluI and HinfI. Three different restriction patterns were identified for each of the two enzymes. By DNA sequencing, using a direct solid-phase automated sequencing method, the isolates could be grouped into 3 different clusters of tet(M) subtypes. The internal DNA homology within each subtype was 98-100%; the homology between clusters was 89-94%. Two different subtypes were identified in 9 of 10 bacterial species, and the remaining species had 3 different subtypes. One of the subtypes (M3) was seen mainly in the anaerobic isolates. This subtype was different from all earlier sequenced structural tet(M) genes present in the Genbank. Most patients had two different subtypes of tet(M), and a third subtype was seen in the 3 patients who exhibited the greatest variety of tetracycline-resistant bacterial species. It appears that the presence of one subtype of the tet(M) gene within a patient or bacterial species does not prevent the acquisition of another subtype of the same gene. This study identified a new subtype of the tet(M) gene and grouped it into 3 distinct yet highly homologous genetic subtypes. 相似文献
6.
Rolandic discharge (RD), noted in the electroencephalography (EEG) of patients with benign epilepsy in childhood with centrotemporal spikes (BECCT) has several unique features. One feature is that the amount or frequency of RDs does not correlate well with the incidence of seizures in BECCT although it is a key finding in the diagnosis of this epileptic syndrome. In this study, we examined the efficacy of antiepileptic drugs focusing on the disappearance of RDs in relationship with seizure control. Forty patients with BECCT who were not medically treated prior to this study were randomly sorted into three groups. Twenty patients were assigned for clonazepam (CZP) treatment, 10 patients for valproate (VPA) and the remaining 10 patients for carbamazepine (CBZ). Each drug was administered for 4 consecutive weeks. EEGs were recorded twice during the study, before and 4 weeks after the medication trial. The effects of each treatment on RDs were assessed. RDs disappeared in 15 of the 20 cases treated with CZP (75%) within 4 weeks while the same was observed in only one of the 10 cases treated with VPA (10%). CBZ failed to demonstrate any effect on RD. In the group treated with CZP, there were no differences in seizure incidence, seizure type and blood concentration of CZP between the patients whose RDs disappeared and those whose RDs remained. 相似文献
7.
P de Lonlay JC Fournet J Rahier MS Gross-Morand F Poggi-Travert V Foussier JP Bonnefont MC Brusset F Brunelle JJ Robert C Nihoul-Fékété JM Saudubray C Junien 《Canadian Metallurgical Quarterly》1997,100(4):802-807
Sporadic persistent hyperinsulinemic hypoglycemia of infancy (PHHI) or nesidioblastosis is a heterogeneous disorder characterized by profound hypoglycemia due to inappropriate hypersecretion of insulin. An important diagnostic goal is to distinguish patients with a focal hyperplasia of islet cells of the pancreas (FoPHHI) from those with a diffuse abnormality of islets (DiPHHI) because management strategies differ significantly. 16 infants with sporadic PHHI resistant to diazoxide and who underwent pancreatectomy were investigated. Selective pancreatic venous sampling coupled with peroperative surgical examination and analysis of extemporaneous frozen sections allowed us to identify 10 cases with FoPHHI and 6 cases with DiPHHI. We show here that in cases of FoPHHI, but not those of DiPHHI, there was specific loss of maternal alleles of the imprinted chromosome region 11p15 in cells of the hyperplastic area of the pancreas but not in normal pancreatic cells. This somatic event is consistent with a proliferative monoclonal lesion. It involves disruption of the balance between monoallelic expression of several maternally and paternally expressed genes. Thus, we provide the first molecular explanation of the heterogeneity of sporadic forms of PHHI such that it is possible to perform only partial pancreatectomy, limited to the focal somatic lesion, so as to avoid iatrogenic diabetes in patients with focal adenomatous hyperplasia. 相似文献
8.
NF Saba JD Sweeney LC Penn JC Lawton RL Yankee CH Huang MS Schanfield 《Canadian Metallurgical Quarterly》1997,37(3):321-324
PURPOSE: We report a case of postoperative reparalysis in the recovery room, following nebulized epinephrine. The patient was pharmacologically reversed with edrophonium after paralysis with rocuronium. CLINICAL FINDINGS: A 12-yr-old girl developed postoperative reparalysis following the intraoperative administration of rocuronium. A total of 0.92 mg.kg-1 rocuronium was administered. After surgery, pharmacological reversal was achieved with 20 mg edrophonium with 0.15 mg atropine sulfate iv 35 min after the last administration of rocuronium. Muscular relaxation was monitored using an ulnar peripheral nerve stimulator (PNS). After reversal, a full train-of-four and sustained tetanus at 50 Hz were present. In the recovery room, following nebulized epinephrine, the patient became apneic. The patient was paralyzed and an ulnar PNS demonstrated only one faint twitch. The paralysis was reversed with 1.5 mg neostigmine with 0.3 mg glycopyrrolate. CONCLUSION: Postoperative reparalysis following rocuronium may be a cause of postoperative respiratory distress. The definitive diagnosis is made using PNS and observing the response to pharmacological reversal. Nebulized epinephrine may have a previously undescribed role in the development of postoperative reparalysis. 相似文献
9.
Vascular injuries may occur as complications of elbow dislocation and usually involve the brachial artery. A case report is presented in which only the radial artery was compromised as a result of the dislocation. 相似文献
10.
The aim of this work was to develop sustained local release systems for radioiodinated iodo-2'-deoxyuridine (125IUdR) from biodegradable polymeric microspheres to facilitate the controlled delivery of 125IUdR to brain tumours. The selective uptake of IUdR into the cell nucleus results in cell disruption over the short range of the low energy Auger electrons. The biodegradable microspheres can be precisely implanted in the brain by stereotactic techniques and the IUdR within the microspheres is protected from degradation and thus a sustained source of radiolabelled IUdR is available in the vicinity of the residual tumour cells. Poly(lactic-co-glycolic acid), PLGA (85:15), microspheres containing cold IUdR and the Auger-electron emitter 125I, as 125IUdR were prepared using the O/W, O/O and W/O/W emulsion-solvent evaporation methods. The W/O/W emulsion method was most effective in achieving good drug loading with the use of bovine plasma in the internal water phase. Also effective in improving the drug loading was the use of 20% acetone in the dichloromethane and the presence of Span 40 in the organic phase. Electrolytes (NaCl and IUdR) in the external aqueous phase also improved drug loading. After an initial rapid release from the microspheres, a sustained release was observed over 15 days for the 'cold' IUdR. The sustained release portions of the release curves showed Higuchi (t1/2), diffusion controlled release kinetics. The radiolabelled IUdR microspheres showed a burst release effect of 30-40% followed by a sustained release over 35 days. 相似文献