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排序方式: 共有339条查询结果,搜索用时 15 毫秒
141.
The economic rise of the BRICS countries(Brazil, Russia, India, China and South Africa) is closely tied to global energy politics and their increased consumption of global energy. Energy cooperation is one of the main forces behind the development of BRICS. Looking forward, energy concerns will undoubtedly remain an important influencing force for the BRICS, shaping their domestic politics and international relations. The pursuit of oil and gas(China, India, and South Africa) to support economic development and the search for stable petroleum markets(Brazil and Russia) have shaped BRICS relations with other countries and regions. This article is trying to elaborate on the reasons why BRICS Energy cooperation is beneficial for its members; also, this article regards the main challenges hindering cooperation, analyzes BRICS energy cooperation through the use of SWOT analysis and muses potential strategic points for BRICS countries up until 2050. 相似文献
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143.
We investigate the application of expectation maximization (EM) algorithms to the classical problem of multiple target tracking (MTT) for a known number of targets. Conventional algorithms, which deal with this problem, have a computational complexity that depends exponentially on the number of targets, and usually divide the problem into a localization stage and a tracking stage. The new algorithms achieve a linear dependency and integrate these two stages. Three optimization criteria are proposed, using deterministic and stochastic dynamic models for the targets 相似文献
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145.
Pavel A. Domnin Vladislav A. Parfenov Alexey S. Kononikhin Stanislav V. Petrov Nataliya V. Shevlyagina Anastasia Yu. Arkhipova Elizaveta V. Koudan Elizaveta K. Nezhurina Alexander G. Brzhozovskiy Anna E. Bugrova Anastasia M. Moysenovich Alexandr A. Levin Pavel A. Karalkin Frederico D. A. S. Pereira Vladimir G. Zhukhovitsky Elena S. Lobakova Vladimir A. Mironov Evgeny N. Nikolaev Yusef D. Khesuani Svetlana A. Ermolaeva 《International journal of molecular sciences》2022,23(3)
Changes in bacterial physiology caused by the combined action of the magnetic force and microgravity were studied in Escherichia coli grown using a specially developed device aboard the International Space Station. The morphology and metabolism of E. coli grown under spaceflight (SF) or combined spaceflight and magnetic force (SF + MF) conditions were compared with ground cultivated bacteria grown under standard (control) or magnetic force (MF) conditions. SF, SF + MF, and MF conditions provided the up-regulation of Ag43 auto-transporter and cell auto-aggregation. The magnetic force caused visible clustering of non-sedimenting bacteria that formed matrix-containing aggregates under SF + MF and MF conditions. Cell auto-aggregation was accompanied by up-regulation of glyoxylate shunt enzymes and Vitamin B12 transporter BtuB. Under SF and SF + MF but not MF conditions nutrition and oxygen limitations were manifested by the down-regulation of glycolysis and TCA enzymes and the up-regulation of methylglyoxal bypass. Bacteria grown under combined SF + MF conditions demonstrated superior up-regulation of enzymes of the methylglyoxal bypass and down-regulation of glycolysis and TCA enzymes compared to SF conditions, suggesting that the magnetic force strengthened the effects of microgravity on the bacterial metabolism. This strengthening appeared to be due to magnetic force-dependent bacterial clustering within a small volume that reinforced the effects of the microgravity-driven absence of convectional flows. 相似文献
146.
Shir Shlomi Roni Toledano Keren Nitzan Sigal Dror Shahaf Emanuela P. Break Dan Frenkel Ravid Doron 《International journal of molecular sciences》2022,23(9)
Stressful unpredictable life events have been implicated in numerous diseases. It is now becoming clear that some life periods are more vulnerable than others. As adolescence is a sensitive period in brain development, the long-term effects of stress during this period could be significant. We investigated the long-term effects of exposure to unpredictable chronic mild stress in adolescent mice on alternative splicing of Sirtuin 1. One-month-old mice were exposed to 4 weeks of UCMS and examined for anxiety and cognition at the age of 2, 4 and 6 months. We found a rise in anxious behavior immediately after the exposure to stress. Notably, there was a long-term impairment of performance in cognitive tasks and an imbalance in Sirtuin 1 and TrkB receptor alternative splicing in the stress-exposed mice compared with controls. To conclude, our results show that exposure to unpredictable chronic mild stress during adolescence affects cognition in adulthood. Understanding pathways affiliated with stress may help minimize the long-term emotional effects of an unpredictable, stressful event. 相似文献
147.
Nataliya V. Mushenkova Nikita G. Nikiforov Nikolay K. Shakhpazyan Varvara A. Orekhova Nikolay K. Sadykhov Alexander N. Orekhov 《International journal of molecular sciences》2022,23(15)
Chronic inflammation is implicated in numerous human pathologies. In particular, low-grade inflammation is currently recognized as an important mechanism of osteoarthritis (OA), at least in some patients. Among the signs of the inflammatory process are elevated macrophage numbers detected in the OA synovium compared to healthy controls. High macrophage counts also correlate with clinical symptoms of the disease. Macrophages are central players in the development of chronic inflammation, pain, cartilage destruction, and bone remodeling. However, macrophages are also involved in tissue repair and remodeling, including cartilage. Therefore, reduction of macrophage content in the joints correlates with deleterious effects in OA models. Macrophage population is heterogeneous and dynamic, with phenotype transitions being induced by a variety of stimuli. In order to effectively use the macrophage inflammatory circuit for treatment of OA, it is important to understand macrophage heterogeneity and interactions with surrounding cells and tissues in the joint. In this review, we discuss functional phenotypes of macrophages and specific targeting approaches relevant for OA treatment development. 相似文献
148.
Alexander M. Starik Pavel S. Kuleshov Alexander S. Sharipov Nataliya S. Titova Chuen-Jinn Tsai 《Combustion and Flame》2014
The comprehensive analysis of chain mechanism development in the Al–H2O system is performed on the base of novel reaction mechanism taking into account quantum chemistry studies of potential energy surfaces of the elementary reactions with Al-containing species and estimations of rate constants of corresponding reaction channels. As well the physical properties of Al-containing species involved in the reaction mechanism and needed for the calculation of their transport coefficients are reported. The developed reaction mechanism makes it possible to describe with reasonable accuracy the experimental data on ignition temperature in Al–O2–Ar and Al–H2O systems and obtain the qualitative agreement with measured value of laminar flame speed. The two-stage regime of ignition in the Al–H2O reacting system was revealed both when the aluminum is in the liquid phase and when it comes into steam environment in the gas phase. It was shown that decreasing the ignition temperature one can increase the hydrogen yield in the combustion exhaust. 相似文献
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C Frenkel JS Peters DM Tieman ME Tiznado AK Handa 《Canadian Metallurgical Quarterly》1998,273(8):4293-4295
We provide genetic evidence that the production of methanol in tomato fruit is regulated by pectin methylesterase (PME, EC 3.1.1.11), an enzyme that catalyzes demethoxylation of pectins. The role of PME in methanol production in tomato fruit was examined by relating the tissue methanol content to the PME enzymatic activity in wild-type Rutgers and isogenic PME antisense fruits with lowered PME activity. In the wild-type, fruit development and ripening were accompanied by an increase in the abundance of PME protein and activity and a corresponding ripening-related increase in methanol content. In the PME antisense pericarp, the level of methanol was greatly reduced in unripe fruit, and diminished methanol content persisted throughout the ripening process. The close correlation between PME activity and levels of methanol in fruit tissues from wild-type and a PME antisense mutant indicates that PME is the primary biosynthetic pathway for methanol production in tomato fruit. Interestingly, ethanol levels that were low and unchanged during ripening of wild-type tomatoes increased progressively with the ripening of PME antisense fruit. In vitro studies indicate that methanol is a competitive inhibitor of the tomato alcohol dehydrogenase (ADH, EC 1.1.1.1) activity suggesting that ADH-catalyzed production of ethanol may be arrested by methanol accumulation in the wild-type but not in the PME mutant where methanol levels remain low. 相似文献