全文获取类型
收费全文 | 3181篇 |
免费 | 118篇 |
国内免费 | 14篇 |
专业分类
电工技术 | 38篇 |
综合类 | 10篇 |
化学工业 | 654篇 |
金属工艺 | 124篇 |
机械仪表 | 97篇 |
建筑科学 | 62篇 |
矿业工程 | 11篇 |
能源动力 | 204篇 |
轻工业 | 295篇 |
水利工程 | 17篇 |
石油天然气 | 5篇 |
无线电 | 283篇 |
一般工业技术 | 742篇 |
冶金工业 | 282篇 |
原子能技术 | 46篇 |
自动化技术 | 443篇 |
出版年
2023年 | 37篇 |
2022年 | 113篇 |
2021年 | 138篇 |
2020年 | 112篇 |
2019年 | 122篇 |
2018年 | 146篇 |
2017年 | 141篇 |
2016年 | 117篇 |
2015年 | 67篇 |
2014年 | 135篇 |
2013年 | 225篇 |
2012年 | 139篇 |
2011年 | 182篇 |
2010年 | 133篇 |
2009年 | 126篇 |
2008年 | 120篇 |
2007年 | 119篇 |
2006年 | 65篇 |
2005年 | 67篇 |
2004年 | 43篇 |
2003年 | 54篇 |
2002年 | 57篇 |
2001年 | 40篇 |
2000年 | 42篇 |
1999年 | 39篇 |
1998年 | 62篇 |
1997年 | 54篇 |
1996年 | 51篇 |
1995年 | 35篇 |
1994年 | 33篇 |
1993年 | 43篇 |
1992年 | 30篇 |
1991年 | 39篇 |
1990年 | 36篇 |
1989年 | 38篇 |
1988年 | 31篇 |
1987年 | 27篇 |
1986年 | 30篇 |
1985年 | 22篇 |
1984年 | 14篇 |
1983年 | 25篇 |
1982年 | 15篇 |
1981年 | 12篇 |
1980年 | 15篇 |
1979年 | 17篇 |
1978年 | 12篇 |
1977年 | 16篇 |
1976年 | 18篇 |
1974年 | 12篇 |
1973年 | 12篇 |
排序方式: 共有3313条查询结果,搜索用时 62 毫秒
11.
Ann Barrett Anuradha Prakash Deborah Sakelakos Irwin Taub Samuel Cohen Yuki Ohashi 《Food Hydrocolloids》1998,12(4):401-408
The effects of composition and thermal treatment on the water sorption and diffusional properties of idealized protein gels arranged in bilayer configurations were determined; these water binding/migration properties were related to the mechanical characteristics of the gels. Samples were prepared from whey protein concentrate (WPC), they consisted of water:WPC ratios of 1.5 to 5.67, and were thermally set for 20–60 min. Moisture migration rates from samples interfaced with filters were determined, as were moisture sorption capacities of samples immersed in water. The physical properties of the gels were assessed by uniaxial compression and microscopy. Results showed that gel strength and consequent extent of protein interaction—as affected by thermal treatment—controlled the ability of the gel structure to absorb water. Sorption was exponentially correlated with gel modulus and linearly correlated with a function of protein content, heating time, and immersion time. Rates of diffusion from interfaced gels were dependent solely on water content. It was concluded that the degree of protein interaction, whether influenced by concentration or thermal treatment, affected network extensibility and thus the capacity of the gels to act as receptors of moisture. Results have implications for the functionality of shelf-stable sandwiches and other multicomponent foods. 相似文献
12.
The relationship between endometriosis and infertility is observed frequently. Patients with both conditions require a conservative approach to their management. Since hormonal therapy is one of those approaches, we sought to compare the efficacy of Danazol and Gestrinone in 80 infertile patients (48 and 32, respectively). Therapy lasted 6 months in both treatment groups, and all patients studied had laboratory tests performed and were clinically evaluated and classified through laparoscopy before and after therapy. The improvement of symptoms and favorable follow-up were similar with both treatments. The reestablishment of menstrual patterns and fertility were also nearly alike in both groups. However, Gestrinone was associated with fewer secondary effects and is easier to administer than Danazol. We conclude that Gestrinone is a useful medication in the management of the infertile patient with endometriosis. 相似文献
13.
14.
15.
16.
17.
A parameter-free geometric model for nuclear absorption is derived from microscopic theory. The expression for the absorption cross section in the eikonal approximation taken in integral form is separated into a geometric contribution, described by an energy-dependent effective radius, and two surface terms which are shown to cancel in an asymptotic series expansion. For collisions of light nuclei, an expression for the effective radius is derived using harmonic-oscillator nuclear density functions. A direct extension to heavy nuclei with Woods-Saxon densities is made by identifying the equivalent half density radius for the harmonic-oscillator functions. Coulomb corrections are incorporated and a simplified geometric form of the Bradt-Peters type obtained. Results spanning the energy range of 1 MeV/nucleon to 1 GeV/nucleon are presented. Good agreement with experimental results are obtained. 相似文献
18.
U. Prakash K. Muraleedharan R. A. Buckley H. Jones P. A. Shenton 《Journal of Materials Science》1996,31(6):1569-1573
Substitutions (0–16 at%) of titanium for iron in Fe3Al-based alloys rapidly solidified by chill-block melt-spinning stabilize the D03 and B2 ordered structures. Rapid solidification results in total suppression of D03 order in binary alloys, whereas alloys containing titanium have D03 structure. D03 and B2 antiphase domain size, lattice parameter and hardness increase with increasing titanium content of the alloy. The deformation mode changes from single (unit) bcc dislocation in binary alloys to two-fold superdislocation configuration in D03Fe3Al-Ti alloys. Mechanical antiphase boundaries are generated by the movement of these imperfect configurations. All the alloys exhibited cleavage tensile failure. The mechanical properties are correlated with the observed structural changes. 相似文献
19.
20.