全文获取类型
收费全文 | 4273篇 |
免费 | 5篇 |
国内免费 | 27篇 |
专业分类
电工技术 | 34篇 |
综合类 | 2篇 |
化学工业 | 671篇 |
金属工艺 | 271篇 |
机械仪表 | 179篇 |
建筑科学 | 58篇 |
矿业工程 | 69篇 |
能源动力 | 97篇 |
轻工业 | 122篇 |
水利工程 | 125篇 |
石油天然气 | 616篇 |
无线电 | 242篇 |
一般工业技术 | 1036篇 |
冶金工业 | 397篇 |
原子能技术 | 265篇 |
自动化技术 | 121篇 |
出版年
2021年 | 57篇 |
2019年 | 48篇 |
2018年 | 119篇 |
2017年 | 108篇 |
2016年 | 120篇 |
2015年 | 48篇 |
2014年 | 93篇 |
2013年 | 119篇 |
2012年 | 111篇 |
2011年 | 142篇 |
2010年 | 138篇 |
2009年 | 127篇 |
2008年 | 117篇 |
2007年 | 106篇 |
2006年 | 90篇 |
2005年 | 72篇 |
2004年 | 60篇 |
2003年 | 73篇 |
2002年 | 71篇 |
2001年 | 78篇 |
2000年 | 70篇 |
1998年 | 57篇 |
1997年 | 46篇 |
1995年 | 48篇 |
1993年 | 42篇 |
1992年 | 60篇 |
1991年 | 71篇 |
1990年 | 49篇 |
1989年 | 74篇 |
1988年 | 93篇 |
1987年 | 79篇 |
1986年 | 67篇 |
1985年 | 65篇 |
1984年 | 64篇 |
1983年 | 62篇 |
1982年 | 64篇 |
1981年 | 67篇 |
1980年 | 68篇 |
1979年 | 87篇 |
1978年 | 91篇 |
1977年 | 54篇 |
1976年 | 71篇 |
1975年 | 77篇 |
1974年 | 92篇 |
1973年 | 85篇 |
1972年 | 91篇 |
1971年 | 59篇 |
1970年 | 73篇 |
1969年 | 55篇 |
1968年 | 45篇 |
排序方式: 共有4305条查询结果,搜索用时 15 毫秒
41.
The dynamics of multi-ion exchange is investigated with consideration for electric fields arising in sorbents when the ions with distinct diffusivities are exchanged. A new model for this process is developed. Simulation shows that the electric field can affect the dynamic break-through curves. The proposed model can be used for the creation of a new process of sorbents regeneration and microcomponents concentration. 相似文献
42.
Anatoly M. Dolgonosov Ruslan Kh. Khamizov Anna N. Krachak Andrei G. Prudkovsky 《Reactive and Functional Polymers》1995,28(1)
A model for multispecies ion-exchange kinetics based on the Nernst-Planck equation is suggested. It is analyzed in comparison with the “locally-determinate” model described by Hwang and Helfferich [1]. The model makes possible simple computation. The conditions for the occurrence of unusual kinetic curves with a maximum are clarified. The proposed model is developed for different types of kinetic problems and verified by the experimental investigation of a kinetics in ternary systems. 相似文献
43.
Anakhaev K. N. Belikov V. V. Amshokov B. Kh. Anakhaev K. K. 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2021,55(3):344-347
Power Technology and Engineering - Advanced methods for determining the hydrological and geomorphological characteristics of torrential pools, which are important for the design of reliable and... 相似文献
44.
Kh. Abolpour M. M. Zahedi 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2012,16(4):729-736
In this note first we develop the notion of general fuzzy automata (GFA) to a new one which is called “BL-general fuzzy automata” and for simplicity, we write BL-GFA, instead of BL-general fuzzy automata. Then we focus on derivation, active state set, membership assignment, output mappings, and concept of belonging to an output label according to the entrance input strings \( X \, (X \in \Upsigma^{ * } ) \) for BL-general fuzzy automata. Therefore, we define the concepts of run map and behavior of BL-GFA. After that we present the morphism with threshold \( \tfrac{{\tau_{1} }}{{\tau_{2} }} \) between two BL-general fuzzy automata. Moreover we give some examples, to clarify these notions. Finally, we prove some theorems. In particular, we show that the isomorphic BL-general fuzzy automata have the same behavior. 相似文献
45.
L. N. Rasskazov Kh. S. Sherimbetov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1989,23(5):262-268
1. | A study of the strength and deformation properties of asphaltic concrete is necessary for analyzing the stress-strain state of dams with asphaltic concrete diaphragms. The properties of asphaltic concrete substantially depend not only on composition but also on temperature. The results obtained make possible an evaluation of the main deformation and strength properties of asphaltic concrete, diaphragms, and facings of dams in relation to composition and temperature at early design stages. |
2. | To obtain generalized indices of properties in relation to composition and temperature of asphaltic concrete, all experiments were conducted on the basis of the mathematical theory of design of experiments. Each experiment had threefold replication. |
3. | The experiments showed that the angle of internal friction for 7% bitumen in excess of 100% of the mineral part is practically independent of temperature. The strength of the material increases due to cohesion, which with a drop of temperature from 200 to 10 increases about fivefold. |
4. | Investigation of the deformation properties of asphaltic concrete showed that the modulus of volume changeE 0 for=0.1 MPa varies by 4–7 times depending on the temperature. |
46.
I. G. Vaulina S. V. Gusev G. N. Sivkova Yu. V. Spirchenko A. I. Kukshinov N. A. Makhutov S. V. Nikitin G. Kh. Khurshudov 《Strength of Materials》1989,21(1):1-7
1. | The order of the calculated and experimental stresses and the character of their variation at the sections of the unit are in satisfactory agreement. This is applicable to both toroidal and poloidal forces. The experiment confirmed that the section 2-2 of the unit is maximally loaded. |
2. | The maximum divergences between the calculated and experimental data are observed at the section of the unit adjoining the cylinder (2-2) where the aforementioned differences between the model and the actual unit has the strongest effect. The divergences decrease if the supports of the unit on the cylinder flanges are not taken into account in the calculations (these results are drawn in Fig. 5 with dashed lines). |
3. | In accordance with the experiment data, the presence of a gap along the lines 1–2 and 3–4 raises the maximum stress in the model by 30...40% as compared to the same in a variant without the gap (35% according to calculations [2]). |
4. | The divergences between the calculated and experimental values of the displacements of the characteristic points of the unit do not exceed 20%. |
47.
M. Kh. Rabinovich V. G. Kudryashov M. V. Markushev 《Metal Science and Heat Treatment》1988,30(8):609-612
1. | The characteristics of strength (u, o 2), plasticity (, ) in the longitudinal and transverse directions, impact toughness in the transverse direction, and also the nominal stress intensity factor K c * are practically independent of the grain size of the alloy AMg6. |
2. | The ultrafine-grained structure somewhat reduces the endurance of the alloy AMg6 in the region of low cycle fatigue and increases endurance and fatigue limit in the region of multicycle fatigue. |
3. | Reduced grain size is accompanied by increased resistance to fatigue crack nucleation in alloy AMg6. |
4. | Alloy AMg6 with ultrafine-grained structure is isotropic in crack resistance, and with coarse-grained structure it is anisotropic. The highest fatigue crack growth rate is found in transverse speciment of coarse-grained material. |
5. | The effect of the grain size on crack resistance depends on the change of the ratio of resistance to crack nucleation and growth at high and low stress levels under conditions of variable loading. |
48.
Data are presented on the influence of prophylactic vitamin administration to schoolchildren in two schools on their health. The morbidity rate significantly decreased, the levels of lysozyme in the saliva, hemoglobin in the blood and total protein in the blood serum rose in the children who received multivitamin "Undevitum" during 5-7 months, as compared to those who were not given the vitamins. Vitamin administration did not influence the physical development of schoolchildren. 相似文献
49.
V. Kh. Kadyrov I. E. Polishchuk A. M. Khairutdinov 《Powder Metallurgy and Metal Ceramics》1985,24(8):628-631
Conclusions The corrosion resistance of detonation-deposited coatings from aluminum- and boron-containing PKh20N80 alloy, nickel, and stainless steel powders markedly surpasses that of constructional steel. The electrochemical properties of such detonation-deposited coatings are determined by their composition and thickness. The basis material is effectively protected against corrosion by 600-Mm-thick coatings. Under conditions of corrosive and mechanical wear detonation-deposited coatings from aluminum- and boron-containing 20% Cr-80% Ni alloy, nickel, and stainless steel powders operate satisfactorily under loads of not more than 5 MPa. The results of service tests have demonstrated the usefulness of detonation-deposited coatings from alloyed powders. Coating with powder of composition III was found to increase the useful life of certain parts of spraying equipment two to two and a half times.Translated from Poroshkovaya Metallurgiya, No. 8 (272), pp. 52–55, August, 1985. 相似文献
50.
Silicon - The effect of external magnetic field during microelement processes is used to discuss the excited semiconductor medium in generalized thermoelasticity theory. The thermal conductivity... 相似文献