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161.
In a previous paper [J. Nucl. Mater. 137 (1985) 7], the present authors have shown that void-lattice formation in crystals under irradiation is a non-equilibrium disorder-order phase transition that is intimately related to the existence of a one-dimensionally diffusing, metastable excited self-interstitial state (crowdion), as assumed in the two-interstitial model. In contrast to all other models of void-lattice formation, this theory explains in a natural way why void lattices possess the same structure and orientation as the host crystal lattices.

In the present work, the theory is extended to the evolution of void lattices after their formation. The three most characteristic features of void-lattice evolution, viz., the occurrence of void-growth saturation, the size uniformity of voids in a void lattice, and the displacive stability of void lattices within a wide range of the governing parameters, are not only predicted by the present theory but can be traced to a common cause — the existence of one-dimensionally migrating crowdions, previously shown to be the cause of void-lattice formation.  相似文献   

162.
Urban rainfall-runoff mobilizes and transports significant loads of metal species. Promulgation of National Pollutant Discharge Elimination System Phase II regulations has spurred development of Unit Operations and Processes (UOPs) Best Management Practices (BMPs) for control of metal species. Recent UOP designs provide both adsorption and filtration using engineered media such as manganese oxide coated polymeric media (MOPM). Divalent metal species adsorption onto a manganese oxide coated polymeric medium was evaluated through batch adsorption experiments using a flowthrough batch reactor. Freundlich isotherms were utilized to fit the experiment data. For the media examined, MOPM, adsorption is pH dependent and results indicate a favorable solute pH range of >6 for metal species adsorption. The relative adsorption affinity of MOPM for four divalent metal species typically found in storm water is Pb(II)>Cu(II)>Cd(II)>Zn(II). Adsorption rates were rapid for this flowthrough batch system with over 50% removal in the first 30 min and over 90% removal within 5 h at a surface loading rate of 500 mL/cm2?min. The pH drift patterns, due to surface complexation, during each experiment, coincided with the metal species removal rate curve. Study results indicated that the inclusion of a thin manganese coating can significantly increase media adsorption capacity. MOPM has a comparable adsorption capacity for the divalent metal species compared to other commercial and research media.  相似文献   
163.
Criticizes F. McKinney's (see record 1977-28569-001) account of the introduction of Gestalt psychology into US psychology for neglecting to mention the contributions of R. M. Ogden. Ogden provided early translations of Koffka's work and wrote the first book by a US psychologist from the viewpoint of Gestalt theory and principles. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
164.
Most current control strategies for storm water treatment utilize fixed or filter-bed media with specific gravity (ρs) greater than 1.0. In contrast to Part I, Part II focuses on such higher density (ρs > 1.0) manganese-oxide-coated media that can be used in combined unit operations and processes for in-situ treatment of storm water. Methods were developed to coat manganese oxides onto sand and cementitious media for storm water treatment. With respect to manganese, coatings of ramsdellite produced a point of zero charge (PZC) of 5.2, while mixtures of birnessite and cryptomelane produced a PZC of 2.6 Manganese oxide increased the specific surface area (SSA) of sand and cementitious media. Manganese-oxide-coated sand (MOCS) produced a larger SSA (2.48-m2∕g), as compared with birnessite-coated media (BCM) (1.51 m2∕g), while the two have a similar surface charge (PZC = 6.4). Manganese-oxide-coated cementitious media (MOCM) produced a significantly larger SSA (19.49 m2∕g), as compared with coated sand, and SEM analyses indicated the surface contained manganese oxide and calcite of thickness 10–30 μm. Based on the results, coated cementitious media provided surface characteristics that can significantly enhance filtration and adsorption of heavy metal in storm water, in comparison to sand.  相似文献   
165.
Life stress was studied in relation to postrecovery attrition, symptom course, and recurrence of depression over 3 yrs. Participants were 67 individuals with recurrent depression who had responded to treatment. Life stress was assessed for the prior 12 wks at acute treatment entry (T1), initial recovery (T2), and after 17 wks of sustained recovery (T3). Severe life events at T1 predicted greater attrition, a more favorable postrecovery symptom course, and a lower likelihood of recurrence over 3 yrs. Life stress at T2 was not predictive of outcomes. Finally, undesirable life events at T3 tended to predict a worse symptom course and a higher likelihood of recurrence, particularly for individuals on medication. The findings are discussed in terms of (a) different processes influenced by life stress over time and (b) limitations of existing longitudinal research for studying the effects of life stress over prolonged intervals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
166.
从翅片效率、单个换热单元的传热系数和整个换热器的换热量三个方面对不同翅片结构、不同管子结构和不同工况下的翅片管换热器由铝翅片换为铜翅片前后的换热特性和成本进行了分析比较:详细给出了各个结构和工况参数单独变化对换铜前后的翅片效率、单位制冷剂侧换热面积上的总传热系数和换热器换热量的影响规律。分析结果发现,翅片越薄、越高,管外径越小,风速越大时,换铜后的翅片管的换热能力增强越大,成本增加越小。在所选择的结构和工况范围内,铜管铜片换热器比铜管铝片换热器的翅片效率约提高0.938%~29.86%、总传热系数约提高9.88%~23.276%、总换热量约提高0.112%~22.3%;对于典型的1.1kW空调器的蒸发器,材料成本约增加8~42元,体积可最多缩小18%。  相似文献   
167.
Inflammatory responses by the innate and adaptive immune systems protect against infections and are essential to health and survival. Many diseases including atherosclerosis, osteoarthritis, rheumatoid arthritis, psoriasis, and obesity involve persistent chronic inflammation. Currently available anti-inflammatory agents, including non-steroidal anti-inflammatory drugs, steroids, and biologics, are often unsafe for chronic use due to adverse effects. The development of effective non-toxic anti-inflammatory agents for chronic use remains an important research arena. We previously reported that oral administration of Oxy210, a semi-synthetic oxysterol, ameliorates non-alcoholic steatohepatitis (NASH) induced by a high-fat diet in APOE*3-Leiden.CETP humanized mouse model of NASH and inhibits expression of hepatic and circulating levels of inflammatory cytokines. Here, we show that Oxy210 also inhibits diet-induced white adipose tissue inflammation in APOE*3-Leiden.CETP mice, evidenced by the inhibition of adipose tissue expression of IL-6, MCP-1, and CD68 macrophage marker. Oxy210 and related analogs exhibit anti-inflammatory effects in macrophages treated with lipopolysaccharide in vitro, mediated through inhibition of toll-like receptor 4 (TLR4), TLR2, and AP-1 signaling, independent of cyclooxygenase enzymes or steroid receptors. The anti-inflammatory effects of Oxy210 are correlated with the inhibition of macrophage polarization. We propose that Oxy210 and its structural analogs may be attractive candidates for future therapeutic development for targeting inflammatory diseases.  相似文献   
168.
In glioblastoma, non-classical human leucocyte antigen E (HLA-E) and HLA-G are frequently overexpressed. HLA-E loaded with peptides derived from HLA class I and from HLA-G contributes to inhibition of natural killer (NK) cells with expression of the inhibitory receptor CD94/NKG2A. We investigated whether NK cells expressing the activating CD94/NKG2C receptor counterpart were able to exert anti-glioma effects. NKG2C+ subsets were preferentially expanded by a feeder cell line engineered to express an artificial disulfide-stabilized trimeric HLA-E ligand (HLA-E*spG). NK cells expanded by a feeder cell line, which facilitates outgrowth of conventional NKG2A+, and fresh NK cells, were included for comparison. Expansion via the HLA-E*spG feeder cells selectively increased the fraction of NKG2C+ NK cells, which displayed a higher frequency of KIR2DL2/L3/S2 and CD16 when compared to expanded NKG2A+ NK cells. NKG2C+ NK cells exhibited increased cytotoxicity against K562 and KIR:HLA-matched and -mismatched primary glioblastoma multiforme (GBM) cells when compared to NKG2A+ NK cells and corresponding fresh NK cells. Cytotoxic responses of NKG2C+ NK cells were even more pronounced when utilizing target cells engineered with HLA-E*spG. These findings support the notion that NKG2C+ NK cells have potential therapeutic value for treating gliomas.  相似文献   
169.
Hfq is a pleiotropic regulator that mediates several aspects of bacterial RNA metabolism. The protein notably regulates translation efficiency and RNA decay in Gram-negative bacteria, usually via its interaction with small regulatory RNAs. Previously, we showed that the Hfq C-terminal region forms an amyloid-like structure and that these fibrils interact with membranes. The immediate consequence of this interaction is a disruption of the membrane, but the effect on Hfq structure was unknown. To investigate details of the mechanism of interaction, the present work uses different in vitro biophysical approaches. We show that the Hfq C-terminal region influences membrane integrity and, conversely, that the membrane specifically affects the amyloid assembly. The reported effect of this bacterial master regulator on membrane integrity is discussed in light of the possible consequence on small regulatory RNA-based regulation.  相似文献   
170.
The primary intent of this work is to present a method for sequentially associating three-dimensional surface measurements acquired by an autonomous exploration agent with models that describe those surfaces. Traditional multiple-viewpoint registration approaches are concerned only with finding the transformation that maps data points to a chosen global frame. Given a parts-based object representation, and assuming that the view correspondence can be found, the problem of associating the registered data with the correct part models still needs to be solved. While traditional approaches are content to group segmented data sets that geometrically overlap one another with the same part, there are cases where this causes ambiguous situations. This paper addresses the model-data association problem as it applies to three-dimensional dynamic object modeling. By tracking the state of part models across subsequent views, we wish to identify possible events that explain model-data association ambiguities and represent them in a Bayesian framework. The model-data association problem is therefore relaxed to allow multiple interpretations of the object's structure, each being assigned a probability. Rather than making a decision at every iteration about an ambiguous mapping, we look to the future for the information needed to disambiguate it. Experimental results are presented to illustrate the effectiveness of the approach.  相似文献   
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