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51.
A nanocrystalline layer was produced on the surface of Ni3Al intermetallic by means of surface mechanical attrition treatment. The surface nanocrystallites were annealed at 250-750 ℃ for 30 min. Microstructure evolution of nanocrystallites during annealing was studied by X-ray diffraction (XRD) and transmission electronic microscope (TEM). The experimental results show that long-rang order recovers rapidly when annealing temperature is below 250℃ and changes slowly at 350-550 ℃, and then it increases rapidly at 750℃. The grain size of nanocrystallites of Ni3Al keeps stable and crystal defects recover when they are annealed below 550℃. The grains grow normally in low temperature annealing and abnormal growth occurs at 750℃. 相似文献
52.
运用XD工艺制备了颗粒增强TiAl基复合材料。增强颗粒均匀分布于TiAl基体中并细化TiAl合金。通过在TiB_2/TiAl、TiC/TiAl复合材料中加入适量的Si,颗粒增强TiAl基复合材料的室温延性得到了改善。 相似文献
53.
在分析武钢含铁化合物二资资源的种类、数量和理化特性的基础上,提出了这部分资源的产品开发方向,并根据这些开发产品国内外市场的分析,指出这种开发将可能取得可观的经济效益。简介了这类开发的工艺和设备。 相似文献
54.
55.
In this paper, we discuss a loop transformation framework that is based on integer non-singular matrices. The transformations
included in this framework are called Λ-transformations and include permutation, skewing and reversal, as well as a transformation
calledloop scaling. This framework is more general than existing ones; however, it is also more difficult to generate code in our framework.
This paper shows how integer lattice theory can be used to generate efficient code. An added advantage of our framework over
existing ones is that there is a simple completion algorithm which, given a partial transformation matrix, produces a full
transformation matrix that satisfies all dependences. This completion procedure has applications in parallelization and in
the generation of code for NUMA machines.
This work was supported by the Cornell Theory Center, NSF Presidential Young Investigator award #CCR-8958543. by NSF Grant
#CCR-9008526, and by a grant from the Hewlett-Packard Company. 相似文献
56.
提出一种电感电流、输出电压瞬时值反馈控制和负载电流前馈控制相结合的复合控制策略。在此基础上,研制了一台800W的单相逆变器。实验结果表明,提出的控制策略改善了逆变器输出电压的波形,提高了系统的暂态特性。 相似文献
57.
A current development trend in research on intelligent systems is to optimize a general intelligent prediction system into an individuation intelligent prediction system that is applied in specialized fields. Protein structure prediction is a challenging international issue. In this paper, we propose a new intelligent prediction system model, designed as a multi-layer compound pyramid model, for predicting secondary protein structure. The model comprises four independent intelligent interfaces and several knowledge discovery methods. The model penetrates throughout the domain knowledge, with the effective attributes chosen by Causal Cellular Automata. Furthermore, a high pure structure database is constructed for training. On the RS126 dataset, the overall state per-residue accuracy, Q3, reached 83.99%, while on the CB513 dataset, Q3 reached 85.58%. Meanwhile, on the CASP8 sequences, the results are superior to those produced by other methods, such as Psipred, Jpred, APSSP2 and BehairPred. These results confirm that our method has a strong generalization ability, and that it provides a model for the construction of other intelligent systems. 相似文献
58.
Novel technology of purification of copper electrolyte 总被引:10,自引:1,他引:10
The effects of arsenic with different valence states on the purification of copper electrolyte were studied and a novel technology of purification of copper electrolyte by copper arsenite was proposed. The results show that the purification performance of As(Ⅲ) compounds is better than that of As(Ⅴ) compounds. The purification technology by copper arsenite has the advantages of simple operation, high purification performance and low cost in comparison with other technologies and its appropriate purification conditions are that copper arsenite concentration is 18 g/L, reaction temperature is 65 ℃ and reaction time is 8 h. The removal rates of Sb and Bi are 53.22% and 58.67% respectively under these conditions. The purification principle show that a kind of yellow precipitate mainly composed of arsenic, antimony ( Ⅴ ), bismuth and oxygen forms in electrolyte after copper arsenite is added, and consequently antimony and bismuth are removed from electrolyte. 相似文献
59.
Jang Mi Han Jae Kyung Sohng Woo-Haeng Lee Tae-Jin Oh Hye Jin Jung 《International journal of molecular sciences》2021,22(5)
We recently discovered a novel nargenicin A1 analog, 23-demethyl 8,13-deoxynargenicin (compound 9), with potential anti-cancer and anti-angiogenic activities against human gastric adenocarcinoma (AGS) cells. To identify the key molecular targets of compound 9, that are responsible for its biological activities, the changes in proteome expression in AGS cells following compound 9 treatment were analyzed using two-dimensional gel electrophoresis (2-DE), followed by MALDI/TOF/MS. Analyses using chemical proteomics and western blotting revealed that compound 9 treatment significantly suppressed the expression of cyclophilin A (CypA), a member of the immunophilin family. Furthermore, compound 9 downregulated CD147-mediated mitogen-activated protein kinase (MAPK) signaling pathway, including c-Jun N-terminal kinase (JNK) and extracellular signal-regulated protein kinase 1/2 (ERK1/2) by inhibiting the expression of CD147, the cellular receptor of CypA. Notably, the responses of AGS cells to CypA knockdown were significantly correlated with the anticancer and antiangiogenic effects of compound 9. CypA siRNAs reduced the expression of CD147 and phosphorylation of JNK and ERK1/2. In addition, the suppressive effects of CypA siRNAs on proliferation, migration, invasion, and angiogenesis induction of AGS cells were associated with G2/M cell cycle arrest, caspase-mediated apoptosis, inhibition of MMP-9 and MMP-2 expression, inactivation of PI3K/AKT/mTOR pathway, and inhibition of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) expression. The specific interaction between compound 9 and CypA was also confirmed using the drug affinity responsive target stability (DARTS) and cellular thermal shift assay (CETSA) approaches. Moreover, in silico docking analysis revealed that the structure of compound 9 was a good fit for the cyclosporin A binding cavity of CypA. Collectively, these findings provide a novel molecular basis for compound 9-mediated suppression of gastric cancer progression through the targeting of CypA. 相似文献
60.
采用苯酚、邻苯二酚、愈创木酚和紫丁香酚为木质素单体模化物,利用两段裂解反应器-在线气相色谱仪(GCs)进行热解实验和产物分析,采用多色谱柱对无机气体(IGs)、C1~C5烃(C1~C5 LHs)、非芳基含氧化合物、酚和芳烃进行定量分析,以确定羟基和甲氧基对木质素热解过程中开环反应及产物分布的影响. 结果显示:羟基和甲氧基可以提高模化物的转化率,且羟基和甲氧基的存在影响芳基开环反应、芳基取代反应和重排反应间的竞争关系,使热解产物分布存在明显差异. 4种模化物热解产物主要是芳环的开环反应产物,包括IGs(质量分数为27.29%~33.56%)和C1~C5烃(20.46%~39.51%). 一氧化碳产率(23.82%~29.18%)随羟基数增加而升高,随甲氧基数增加而降低;二氧化碳产率(0.19%~9.61%)随甲氧基数增加而升高. 羟基和甲氧基的存在降低了C1~C5烃的质量选择性,促进了烷基苯、大分子化合物和焦炭的形成. 相似文献