全文获取类型
收费全文 | 166320篇 |
免费 | 12071篇 |
国内免费 | 6088篇 |
专业分类
电工技术 | 8690篇 |
技术理论 | 9篇 |
综合类 | 8720篇 |
化学工业 | 27226篇 |
金属工艺 | 9971篇 |
机械仪表 | 10045篇 |
建筑科学 | 9782篇 |
矿业工程 | 3933篇 |
能源动力 | 3641篇 |
轻工业 | 9308篇 |
水利工程 | 3137篇 |
石油天然气 | 9522篇 |
武器工业 | 1051篇 |
无线电 | 17498篇 |
一般工业技术 | 26733篇 |
冶金工业 | 11069篇 |
原子能技术 | 4824篇 |
自动化技术 | 19320篇 |
出版年
2024年 | 714篇 |
2023年 | 2316篇 |
2022年 | 4594篇 |
2021年 | 6197篇 |
2020年 | 4664篇 |
2019年 | 4009篇 |
2018年 | 5120篇 |
2017年 | 5574篇 |
2016年 | 5128篇 |
2015年 | 5635篇 |
2014年 | 7289篇 |
2013年 | 8878篇 |
2012年 | 9527篇 |
2011年 | 10224篇 |
2010年 | 8687篇 |
2009年 | 8520篇 |
2008年 | 8399篇 |
2007年 | 7887篇 |
2006年 | 7304篇 |
2005年 | 6240篇 |
2004年 | 4775篇 |
2003年 | 4700篇 |
2002年 | 4739篇 |
2001年 | 4320篇 |
2000年 | 3743篇 |
1999年 | 3314篇 |
1998年 | 2620篇 |
1997年 | 2207篇 |
1996年 | 1973篇 |
1995年 | 1736篇 |
1994年 | 1464篇 |
1993年 | 1244篇 |
1992年 | 1217篇 |
1991年 | 1074篇 |
1990年 | 1089篇 |
1989年 | 1009篇 |
1988年 | 898篇 |
1987年 | 841篇 |
1986年 | 763篇 |
1985年 | 715篇 |
1984年 | 701篇 |
1981年 | 668篇 |
1979年 | 736篇 |
1978年 | 777篇 |
1977年 | 739篇 |
1976年 | 755篇 |
1975年 | 713篇 |
1974年 | 719篇 |
1973年 | 723篇 |
1972年 | 705篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
Monodisperse silica particles of about 0.3m diameter are suspended in methacrylate monomer using a carefully selected dispersant. Many steric dispersants are hydrocarbon chains with a reactive end-group. These are not effective as dispersants for silica in moderately polar solvents, such as esters and the methacrylate monomers. Good dispersion was obtained with a methacrylate polymer terminated by a chlorosilane end group. Settling or centrifugation of these unagglomerated dispersions gives well-packed particle beds. Polymerization of the surrounding monomer produces composite materials with high packing fractions and a high degree of regularity. Moduli and strengths of these composites are reported. 相似文献
982.
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%. |
983.
Yu. K. Kovneristyi N. M. Matveeva L. A. Matlakhova 《Metal Science and Heat Treatment》1988,30(11):847-851
Conclusion In alloys of the TiNi-TiCu system prepared in the form of thin tapes by ultrarapid melt cooling the B2-phase, which is unstable towards martensitic transformation B2B19, contains up to 35% Cu, whereas in bulk alloys prepared in the form of an ingot cooled at normal rates it contains about 10% Cu close to the MS. In alloys containing up to 35% Cu there are no untransformed brittle phases preventing development of martensitic transformation throughout the volume of the material. The structure of alloys is quite uniform, particularly those obtained by crystallizing from the amorphous condition, and the grain size of the high-temperature phase is a fraction of a micron. The fine structure of alloys close to a globular at a high cooling rate. Thus, range of practically important alloys of the B2 type with inelastic behavior effects, e.g., the shape memory effect, is considerably expanded.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 38–41, November, 1988. 相似文献
984.
Yu. G. Trofimenkov 《Soil Mechanics and Foundation Engineering》1988,25(1):45-49
Conclusion 1. For clayey soils, it is possible to confirm, using the curves in Fig. 2, the interlinking of the resultant data from the results of penetration and laboratory determinations of the compression modulus and the undrained-shear strength.2. For sandy soils, it is possible to determine with reliability the angle from Fig. 3 for different penetration depths and different values of q.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 28–30, January–February, 1978. 相似文献
985.
986.
987.
M. Yu. Pazyuk V. A. Syromyasskii A. N. Nikolaenko Yu. M. Zinchenko V. D. Getalo 《Metallurgist》1988,32(2):55-56
Zaporozhe Industrial Institute. Zaporozhstal' Combine. Translated from Metallurg, No. 2, pp. 19–21, February, 1988. 相似文献
988.
A. P. Osipov M. G. Semena Yu. Yu. Sergeev 《Journal of Engineering Physics and Thermophysics》1988,54(5):539-542
We develop a theoretical model of the development of a temperature jump across the boundary between phases during a phase transition in pure liquids.Notation G1
mass flux of molecules of the liquid into the liquid
- G2
mass flux of molecules of the liquid into the vapor
- Gv
mass flux of vapor molecules
- T1
vapor temperature near the liquid surface
- T2
temperature of the liquid
- Tv
vapor temperature
- R
universal gas constant
- cp, cv
specific heats
- r
heat of vaporization
- q
heat flux density
- K
ratio cp/cv
-
parameter of the phase transition
- F0
area of the interface
- P1
pressure of the liquid
- P2
phase transition pressure
- Pv
vapor pressure
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 5, pp. 793–797, May, 1988. 相似文献
989.
V. G. Rifert Yu. V. Putilin V. L. Podbereznyi 《Journal of Engineering Physics and Thermophysics》1988,54(5):490-492
Experimental data are presented for the local heat liberation coefficient for flow of a liquid film on a smooth horizontal tube, permitting refinement of the concept of the heat exchange mechanism.Notation , , ,a
kinematic viscosity, thermal conductivity, density, and thermal diffusivity of liquid
-
liquid film thickness
-
irrigation density
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 5, pp. 736–739, May, 1988. 相似文献
990.
V. P. Trushechkin Yu. A. Balashov V. S. Senin V. V. Podnebesnov 《Strength of Materials》1988,20(4):422-425
1. | The combined theoretical and experimental investigation of the thermal and stress state of the nozzle vane of a gas turbine confirmed the possibility of using the newly devised experimental strain gauges in the range of working temperatures 293–973°K. |
2. | In modeling the pin system of the outlet channel by thin continuous baffles we obtained satisfactory agreement of calculation and experiment at all points of measurement uniformly distributed over the surface of the vane. |