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131.
132.
E Forleo-Neto ES Carvalho IC Fuentes MS Precivale LH Forleo CK Farhat 《Canadian Metallurgical Quarterly》1997,15(17-18):1898-1901
The serological response to MMR vaccine was evaluated in 109 9-month-old infants having no history of measles vaccination, and in 98 15-month-old children who had received monocomponent measles immunisation at 9 months. The combined vaccine contained Schwarz, Urabe Am9, and Wistar RA 27/3 live attenuated virus strains. Preimmunisation antibody levels were extremely low for the 9-month-old children, indicating that maternally-transmitted antibodies do not persist at this age. In the case of mumps, preimmunisation antibody levels were significantly higher in the 15-month-old than in the 9-month-old group. A difference between groups in terms of postimmunisation antibody titres was observed only for rubella, with titres being significantly higher in the older group. Seroconversion rates were high in both groups and no serious events attributable to vaccination were observed. The MMR vaccine can thus be administered to children as young as 9 months of age. Evidence for the efficacy of a two-dose schedule, i.e. at 9 and 15 months, is presented. 相似文献
133.
P Jiang P Zucker MR Atkinson ES Kamberov W Tirasophon P Chandran BR Schefke AJ Ninfa 《Canadian Metallurgical Quarterly》1997,179(13):4342-4353
The PII protein, encoded by glnB, is known to interact with three bifunctional signal transducing enzymes (uridylyltransferase/uridylyl-removing enzyme, adenylyltransferase, and the kinase/phosphatase nitrogen regulator II [NRII or NtrB]) and three small-molecule effectors, glutamate, 2-ketoglutarate, and ATP. We constructed 15 conservative alterations of PII by site-specific mutagenesis of glnB and also isolated three random glnB mutants affecting nitrogen regulation. The abilities of the 18 altered PII proteins to interact with the PII receptors and the small-molecule effectors 2-ketoglutarate and ATP were examined by using purified components. Results with certain mutants suggested that the specificity for the various protein receptors was altered; other mutations affected the interaction with all three receptors and the small-molecule effectors to various extents. The apex of the large solvent-exposed T loop of the PII protein (P. D. Carr, E. Cheah, P. M. Suffolk, S. G. Vasudevan, N. E. Dixon, and D. L. Ollis, Acta Crytallogr. Sect. D 52:93-104, 1996), which includes the site of PII modification, was not required for the binding of small-molecule effectors but was necessary for the interaction with all three receptors. Mutations altering residues of this loop or affecting the nearby B loop of PII, which line a cleft between monomers in the trimeric PII, affected the interactions with protein receptors and the binding of small-molecule ligands. Thus, our results support the predictions made from structural studies that the exposed loops of PII and cleft formed at their interface are the sites of regulatory interactions. 相似文献
134.
A Lundgaard C Aalkjaer A Bjurholm MJ Mulvany ES Hansen 《Canadian Metallurgical Quarterly》1997,68(5):481-489
We assessed the effects of vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP), substance P (SP), and bradykinin in arteries (diameter approximately 230 microns) isolated from cancellous bone from pigs. Arterial segments (2 mm long) were mounted on a myograph for measurement of isometric force development. After submaximal precontraction with norepinephrine, VIP (10(-10)-10(-7) M), CGRP (10(-11)-10(-7) M), SP (10(-6) M), and bradykinin (10(-11)-10(-6) M) were added. 44 arterial segments (23 pigs) were investigated. VIP-, CGRP-, and bradykinin induced a concentration-dependent vasorelaxation, while SP mediated a transient relaxation. After mechanical removal of the endothelium, the effects of SP and bradykinin were completely abolished, while the relaxation to CGRP was still pronounced. This indicates that the effects of SP and bradykinin are mediated by the endothelium, while CGRP mainly mediates relaxation by a direct effect on vascular smooth muscle cells. The relaxations to CGRP and bradykinin were still significant after inhibition of nitric oxide synthase with 10(-4) M N omega-nitro-L-arginine (L-NNA) and inhibition of prostaglandin synthesis with 10(-5) M indomethacin, indicating the existence of an alternative vasorelaxing pathway. Our findings support the theory of a vasoregulatory role of neuropeptides in bone. 相似文献
135.
136.
In recent months, neural fetal retina has been transplanted into blind human patients affected by Retinitis Pigmentosa. Initial success, as documented by improved visual activity, has been reported (del Cerro et al., Neuroscience Abstract, 1996). With the rapid progress in human patients, additional questions are arising concerning transplantation issues. Additional answers and further success in treating clinical disease will necessarily come from new laboratory research in animal models as well as in vitro systems. This increases the need for evaluation of the data already gathered over the first decade of retinal transplantation. The extensive experimental background work that preceded the current wave of human retinal transplants is reviewed in this paper, with particular emphasis given to the work dealing with the transplantation of neural retina. 相似文献
137.
138.
KE You-Ten ES Muise A Itié E Michaliszyn J Wagner S Jothy WS Lapp ML Tremblay 《Canadian Metallurgical Quarterly》1997,186(5):683-693
The T cell protein tyrosine phosphatase (TC-PTP) is one of the most abundant mammalian tyrosine phosphatases in hematopoietic cells; however, its role in hematopoietic cell function remains unknown. In this report, we investigated the physiological function(s) of TC-PTP by generating TC-PTP-deficient mutant mice. The three genotypes (+/+, +/-, -/-) showed mendelian segregation at birth (1:2:1) demonstrating that the absence of TC-PTP was not lethal in utero, but all homozygous mutant mice died by 3-5 wk of age, displaying runting, splenomegaly, and lymphadenopathy. Homozygous mice exhibited specific defects in bone marrow (BM), B cell lymphopoiesis, and erythropoiesis, as well as impaired T and B cell functions. However, myeloid and macrophage development in the BM and T cell development in the thymus were not significantly affected. BM transplantation experiments showed that hematopoietic failure in TC-PTP -/- animals was not due to a stem cell defect, but rather to a stromal cell deficiency. This study demonstrates that TC-PTP plays a significant role in both hematopoiesis and immune function. 相似文献
139.
JS Park ES Hwang SN Park HK Ahn SJ Um CJ Kim SJ Kim SE Namkoong 《Canadian Metallurgical Quarterly》1997,65(1):121-129
Entamoeba histolytica and Entamoeba dispar have only recently been defined as two separate species. E. histolytica, the pathogenic species, is the microorganism causing invasive intestinal amoebiasis and/or liver abscess, while the morphologically similar E. dispar is nonpathogenic and noninvasive. The gold standard for the distinction of the two species has been the isoenzyme electrophoresis of phosphoglucomutases (EC 5.4.2.2) and hexokinases (EC 2.7.1.1), but there had also been a controversy about the possibility of a conversion of isoenzyme patterns. In this study, we cloned the phosphoglucomutase (PGM) cDNAs from the pathogenic and the nonpathogenic species. The deduced amino acid sequences were only 2.4% different. The cDNAs were expressed in Escherichia coli under the control of a T7 RNA polymerase promoter. The recombinant polypeptides displayed strong phosphoglucomutase activity, each of the recombinant enzymes comigrated with its natural counterpart from E. histolytica and E. dispar in the starch gel electrophoresis. Our results give a biochemical interpretation of the PGM isoenzyme pattern and support the clear distinction between the two species. 相似文献
140.
The mechanisms behind nocturnal rises of gastric pH are unknown. We have analyzed the relation between interdigestive duodenal peristalsis and nocturnal pH in the gastric antrum. Simultaneous recording of antroduodenal pressures and intragastric pH was performed in 11 healthy subjects (six men, five women) overnight for 8 hr, using a catheter with seven pressure recording points and an antral glass pH electrode. Three pressure recording sites were closely spaced in the descending duodenum. Altogether 46 phase III activities were recorded. A retroperistaltic sequence in the last part of phase III was observed in 31 phase III activities (67.4%), while 15 phase III activities lacked retroperistalsis. All subjects had retroperistalsis in at least one phase III at night with a median of 60% (52-100%) (interquartile range). The duration of the whole phase III was 5.1 (3.1-7.0) min, whereas the duration of the retroperistaltic period was 2.0 (1.5-3.2) min, corresponding to 45% (23-64%) of the duration of phase III. The peak of antral pH occurred 7.4 (6.0-13.0) min from the start of the phase III in the duodenum and and the rise in pH lasted for 8.0 (4.8-12.0) min. Measurement of pH for a period of 10 min before and after phase III, demonstrated an increase in median pH from 1.2 (1.1-1.9) to 3.2 (1.6-4.7), respectively (P < 0.001). Phase III activities without duodenal retroperistalsis were not followed by a significant antral pH change (median 1.7 vs 1.8 before and after phase III, respectively). Increases of pH unrelated to phase III were uncommon, only 1.0 (1.0-2.2) events per night were observed and lasted for a short period of time, 2.1 (0.5-3.2) min. The results indicate that the cyclic rise in antral pH at night is due to a physiological duodenogastric reflux, caused by duodenal retroperistalsis in phase III. This reflux may play a role in protection of the antral mucosa. 相似文献