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941.
Mobilization of hepatic cadmium (Cd) in pregnant rats was investigated. Female Sprague-Dawley rats (200-250 g) were injected subcutaneously, daily with 1.0 mg Cd/kg body weight as CdCl2 for 8 days. A group of these rats was made pregnant. Copper (Cu), zinc (Zn), Cd, and metallothionein (MT) concentrations in the liver, kidney, and plasma of the control and Cd-injected, pregnant and nonpregnant rats, were compared. The hepatic Cd concentration of the Cd-injected rats decreased by 40% during pregnancy and became significantly lower than that of the nonpregnant Cd-injected rats. On the other hand, there was a concomitant increase (60%) of Cd concentrations in the kidney of the Cd-injected pregnant rats. MT in the Cd-injected rats also showed a similar pattern of decrease in hepatic concentrations and increase in renal concentrations during pregnancy. Both Cd and MT contents in the placenta of the Cd-injected rats were higher than those of the control and there was a significant increase over the gestational period. Plasma Cd and MT concentrations of the Cd-injected pregnant rats were higher than those of Cd-injected nonpregnant rats. These results suggest that pregnancy can mobilize the hepatic Cd which can be transferred to the kidney and placenta through the blood plasma. Moreover, the blood urea nitrogen levels of the pregnant Cd-injected rats were increased on Gestation Day 21 and 7 days after delivery, indicating signs of Cd nephropathy. The hepatic Cd, Cu, Zn, and MT concentrations of the newborn rats, however, were unaltered by Cd injections. Therefore, it is possible that pregnancy may induce a high risk of Cd nephrotoxicity in women with chronic Cd exposure. 相似文献
942.
PH Pretorius AJ van Rensburg A van Aswegen MG L?tter DE Serfontein CP Herbst 《Canadian Metallurgical Quarterly》1993,34(2):330-335
The accuracy of quantitation of radionuclide distributions in human tissue with the scintillation camera is decreased by attenuation and scatter of photons. If scatter correction is applied satisfactorily, narrow beam attenuation can be applied. In this article, a scatter correction technique, the channel ratio (CR) method, is introduced. The CR scatter correction method is proposed for quantitation of the radionuclide distribution in organs. The improvement in the geometrical resolution was measured and examples of clinical images are presented. In this method, the change in the ratio of counts from two symmetrical adjacent energy windows straddling the energy photopeak was used to eliminate the contribution of scattered photons during imaging with 99mTc. The theory and methods for the empirical affirmation are described. To apply the CR scatter correction method, two constants, the ratio of primary photons G and the ratio of scattered photons H in the same windows, were determined. Different sized sources in varying depths of water were imaged. When the source activities were quantified after scatter correction with the CR method, the measurements ranged from 96%-108% in comparison to the reference value in 100 mm water. The scatter fraction increased from 0.20 in 10 mm water to 1.44 in 200 mm water. The geometrical resolution expressed as full width at tenth maximum in 150 mm water improved by 30.4% and was restored to the value of the geometrical resolution in air. The CR scatter correction method is a simple method to correct for scatter in order to facilitate accurate quantitation of the radionuclide distribution during imaging with a scintillation camera. 相似文献
943.
In vitro pore-forming activity of the lantibiotic nisin. Role of protonmotive force and lipid composition 总被引:13,自引:0,他引:13
Human prostate cancer displays a high degree of variability in its rate of spread, which could be due largely to differences in the invasive potential of the tumor cells. The degradation of the basal lamina and stromal extracellular matrix is mediated in part by the secretion of matrix metalloproteinases (MMPs). Matrilysin (PUMP-1, MMP-7) and gelatinase A (M(r) 72,000 type IV collagenase, MMP-2) have been shown to be overexpressed in prostate carcinoma. We have expressed the single MMP matrilysin in the tumorigenic but nonmetastatic human prostate tumor cell line DU-145 to determine if matrilysin has a functional role in prostate tumor cell invasion. DU-145 cells expressing matrilysin were significantly more invasive than vector-only transfected cell lines as assayed by a severe combined immunodeficient mouse model of tumor cell invasion. Vector-only transfected DU-145 cells injected i.p. into severe combined immunodeficient mice invaded the diaphragm in only 1 of 9 mice (11%), whereas matrilysin-transfected DU-145 cells invaded the diaphragm in 12 of 18 mice (66%). The difference between the controls and matrilysin-transfected cells was statistically significant (P < 0.006). These results suggest a functional role for matrilysin in the initial invasion of prostate cancer through the epithelial basal lamina and into the surrounding stroma. 相似文献
944.
The purpose of this study was to compare classification systems of active range of motion of the finger after flexor tendon surgery in zone II of the hand. Active range of motion of 20 fingers (16 subjects) was classified according to five systems. Agreement between the systems was only fair. Strickland's original system and the Louisville system rated the results most strictly, followed by Strickland's adjusted system. Buck-Gramcko's systems (in centimeters and degrees) rated the results least strictly. Strickland's systems conformed most closely to measurement principles. This article concludes that at this time Strickland's original classification system is preferable for scientific and clinical purposes. However, additional research is needed to evaluate reliability of the measurement, the variability of the scaling factor of 175 degrees, the sensitivity of the measurement, and the validity of the measurement with regard to functional use of the finger and gliding of the repaired tendon. 相似文献
945.
We present two cases of community acquired pneumonia (extra-hospital) of severe onset, secondary to Chlamydia psittaci of avian origin. Each patient have bought a parakeet in the same pet-shop, and took care of them personally. Both developed a respiratory insufficiency, one of them needing mechanical ventilation. Out of nine relatives to whom serological determinations were performed, there was evidence of infection in two of them, but only one referred an auto-limited febrile syndrome during that period of time. Psittacosis incidence is discussed as origin of community acquired pneumonias, as well as its epidemiology, diagnosis and treatment. 相似文献
946.
EC de Almeida MS Leite MA da Silva L Rassi Júnior 《Canadian Metallurgical Quarterly》1993,60(6):417-419
The authors report a case of rhabdomyoma of the right ventricular cavity with outlet obstruction in a three-months old infant. The diagnosis was established by echocardiography. Bidimensional echocardiography study showed a polypoid tumor of the right ventricle. During the systole it was projected through the pulmonary valve, obstructing part of it. The Doppler study showed an important gradient between the right ventricle and the pulmonary artery. The resection was performed with success. The diagnosis of cardiac rhabdomyoma was made by microscopic study. It is emphasized the importance of the echocardiographic study in an infant with oligosymptomatic cardiac murmurs. 相似文献
947.
948.
The effects of differences in the rate and composition of intravenous fluid replacement for urine loss on the pharmacokinetics and pharmacodynamics of azosemide were evaluated using rabbit as the animal model. Each rabbit received a 4h constant intravenous infusion of 1 mg kg-1 azosemide with 0% replacement (treatment I, n = 4), 50% replacement (treatment II, n = 5), and 100% replacement (treatment III, n = 5) with lactated Ringer's solution, as well as with 100% replacement with 5% dextrose in water (D-5-W, treatment IV; n = 5). Renal clearance and urinary excretion rate of the drug in treatment III were considerably higher than those in treatments I, II, and IV. In spite of the similarities in kinetic properties, diuretic and/or natriuretic effects of azosemide were markedly different among the four treatments. For example, the mean 8 h urine output values were 98.2, 178, 733, and 237 mL for treatments I-IV, respectively, and the corresponding values for sodium excretion were 11.1, 19.4, 76.4, and 14.2 mmol, and for chloride 13.4, 23.8, 78.9, and 17.1 mmol. Except for treatment III, diuresis and/or natriuresis were found to be time dependent, generally decreasing with time until reaching a low plateau during the later hours of infusion. The present findings also show that (i) no fluid replacement and 100% replacement with D-5-W both produce the same degree (not significantly different) of severe acute tolerance in natriuresis, indicating the insignificance of water compensation in tolerance development; (ii) in treatment II, where neutral sodium balance was achieved, the development of acute tolerance in diuresis can mainly be attributed to negative water balance under this special condition; and (iii) at steady state the hourly diuresis and natriuresis can differ up to about 6.87- and 5.21-fold between treatments. Some implications for the bioequivalence evaluation of dosage forms of azosemide are discussed. 相似文献
949.
950.
The refolding of the tetrameric, metalloenzyme glycerol dehydrogenase (GDH) from Bacillus stearothermophilus has been investigated using stopped-flow fluorescence and circular dichroism spectroscopy. The effects of metal ions on the refolding of the native enzyme and the refolding of a monomeric mutant ([A208]GDH) have also been studied. The refolding process of the wild-type enzyme is at least biphasic; 70% of the respective signal changes occur in the first 2 ms followed by a slower process with a half-life of 3 s. The presence of the metal ion does not affect the slowest biphasic refolding rate, which is virtually the same for all three versions of the enzyme. The presence of GroEL slows down the first phase of refolding. The reassociation of subunits was examined by measuring the regain in catalytic activity and the enhancement in the fluorescence emission from NADH on binding to the oligomeric form of the enzyme. The rate and extent of reassociation is dependent on enzyme concentration and the extent of reactivation is dependent on the presence of the metal ion. The reassociation process was more efficient in the presence of NADH particularly for the metal-depleted enzyme (apo-GDH). The presence of GroEL or GroEL plus ATP leads to a higher yield of reassociation and therefore catalytically active enzyme. The additional presence of Mg-ATP does not affect the extent of reassociation, but has a small positive effect on the rate of reassociation. These data suggest that GDH is bound weakly to GroEL and that GroES is not required for release of the protein. 相似文献