全文获取类型
收费全文 | 862篇 |
免费 | 31篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 18篇 |
综合类 | 1篇 |
化学工业 | 312篇 |
金属工艺 | 32篇 |
机械仪表 | 24篇 |
建筑科学 | 20篇 |
能源动力 | 22篇 |
轻工业 | 63篇 |
水利工程 | 4篇 |
石油天然气 | 1篇 |
无线电 | 28篇 |
一般工业技术 | 207篇 |
冶金工业 | 69篇 |
原子能技术 | 36篇 |
自动化技术 | 58篇 |
出版年
2023年 | 9篇 |
2022年 | 21篇 |
2021年 | 18篇 |
2020年 | 10篇 |
2019年 | 22篇 |
2018年 | 20篇 |
2017年 | 19篇 |
2016年 | 20篇 |
2015年 | 12篇 |
2014年 | 28篇 |
2013年 | 54篇 |
2012年 | 52篇 |
2011年 | 56篇 |
2010年 | 42篇 |
2009年 | 42篇 |
2008年 | 48篇 |
2007年 | 47篇 |
2006年 | 32篇 |
2005年 | 33篇 |
2004年 | 33篇 |
2003年 | 26篇 |
2002年 | 22篇 |
2001年 | 16篇 |
2000年 | 16篇 |
1999年 | 19篇 |
1998年 | 34篇 |
1997年 | 20篇 |
1996年 | 19篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 3篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1974年 | 1篇 |
1973年 | 4篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有895条查询结果,搜索用时 15 毫秒
121.
The time variations in the electrode potential and mass of an electrodeposited CdTe layer when immersed in a deposition bath under an open-circuit condition were examined using an electrochemical QCM in order to observe the oxidation behavior due to dissolved oxygen. The morphology, composition, and crystallinity of the CdTe layer were also examined by SEM, EPMA, and XRD measurements. In the early stage of immersion, mostly only Cd atoms in the CdTe were found to dissolve from the zinc blende-type CdTe lattice, keeping the flat and smooth surface morphology intact. Then, the remaining Te formed a lattice of elemental Te and covered the CdTe layer. The electrolyte could penetrate the Te layer and access the CdTe layer's surface because the Te layer was porous due to the elution of Cd atoms. Therefore, the preferential dissolution of Cd species continued to occur, and finally, only the porous Te layer remained on the substrate. This dissolution of CdTe supports the validity of the potential-pH diagram of the Cd-Te-NH3-H2O system. 相似文献
122.
Kentaro Okada Masataka Mori Kazuko Shimazaki Tatsuji Chuman 《Journal of chemical ecology》1990,16(9):2605-2614
Bioassays were performed on malePeriplaneta americana L. using synthetic (–)-periplanone-B (P-B) and Hauptmann's (–)-periplanone-A (P-A), and their mixtures at various ratios to estimate the roles of both periplanones for the sexual communication of the species. Both P-A and P-B elicited qualitatively the same responses, such as antennal movement, rapid locomotion, wing raising, and homosexual behavior of male cockroaches, but the threshold of the pheromone activities for P-B was two orders of magnitude lower than that of P-A. Neither synergistic nor inhibitory but only a simple integrated effect on the responses was observed when mixtures of P-A and P-B were applied. 相似文献
123.
124.
Kentaro Shinoda Atsushi Yamada Makoto Kambara Yoichi Kojima Toyonobu Yoshida 《Journal of Thermal Spray Technology》2007,16(2):300-305
The deformation of plasma-sprayed alumina droplets of 35-55 μm diameter d with an impact velocity of around 90 m/s has been investigated over various micro-patterned substrates with an arithmetic
mean roughness of 0.5 μm. On a line-and-space pattern, droplets exhibited elliptical splats extending in the direction perpendicular
to the line, when the normalized pattern spacing λ (= x/d) was 0.1-0.3, where x is the pattern spacing. The fingering of the splats was also caused by a concave pattern as well as by a convex pattern and
the number of fingers significantly increased at λ = 0.2. In addition, holes suggesting air entrapment were observed off center
in the bottom side of each splat by approximately 1.5 times the radius of the droplets, regardless of the pattern. These results
suggest the importance of the surface design of substrate on the micrometer scale in plasma spraying. 相似文献
125.
Hideki Hyuga Kiyoshi Hirao Mark I. Jones Yukihiko Yamauchi 《Journal of the American Ceramic Society》2003,86(7):1081-1087
Si3 N4 /carbon fiber composites were fabricated using several types of fiber. All the composites had higher fracture toughness compared with monolithic Si3 N4 ceramics. Tribological properties were investigated by a ball-on-disk method under unlubricated conditions. The composite containing fibers with a high orientation of graphite layers and high graphite content indicated a low friction coefficient. It was identified, by Raman spectroscopy, that graphite was transferred from the composite to the Si3 N4 ball of the counterbody during the wear test. This transferred layer was effective for producing the low friction behavior of the composite. 相似文献
126.
The AE method is an effective technique for inspecting corrosion damage of mild steel, such as tank bottom floors. However, the correlation between AE signals and corrosion behaviour for mild steel has not yet been fully clarified. In the present study, the authors considered that the corrosion regions of bottom floors become a strong acid environment by Cl−, as reported in a previous study. Thus, the polarization resistance for the test pieces of mild steel was measured with an AC impedance method under a strong acid environment. It was clear that the polarization resistance indicated the corrosion rate for a test piece of mild steel in the experiments. While measuring the AE signals, the corrosion rate was monitored with a test piece. As a result, the AE signal showed good correlation with the corrosion rates of the test pieces. The corrosion behaviour of the test pieces was then discussed with the corrosion potential measured during the experiments. Furthermore, the cathode current was changed to control the generated hydrogen gas volume. The volume of the hydrogen gas generated from the cathode reaction was correlated to the AE signals. 相似文献
127.
The electrical conductivity of iron-containing silica glasses was measured from 80 to 350 K. The conductivity data were analyzed based on the hopping conduction theory. The hopping binding energy (Wp ) and disorder energy WD ) were calculated from the activation energy at high and low temperatures. The disorder energy obtained was much lower than reported for FeO-P2 O5 glasses, but similar to that for vandium-containing glasses. 相似文献
128.
Diffusion of cobalt,chromium, and titanium in Ni3Al 总被引:1,自引:0,他引:1
Y. Minamino S. B. Jung T. Yamane K. Hirao 《Metallurgical and Materials Transactions A》1992,23(10):2783-2790
Diffusion studies of cobalt, chromium, and titanium in Ni3Al (γ′) at temperatures between 1298 and 1573 K have been performed using diffusion couples of (Ni-24.2 at. pct Al/Ni-24.4
at. pct Al-2.91 at. pct Co), (Ni-24.2 at. pct Al/Ni-23.1 at. pct Al-2.84 at. pct Cr), and (Ni-24.2 at. pct Al/Ni-20.9 at.
pct Al-3.17 at. pct Ti). The diffusion profiles were measured by an electron probe microanalyzer, and the diffusion coefficients
of cobalt, chromium, and tita-nium in γ′ containing 24.2 at. pct Al were determined from those diffusion profiles by Hall’s
method. The temperature dependencies of their diffusion coefficients (m[su2]/s) are as follows: ~D(Co)
= (4.2 ± 1.2) × 1O-3exp {-325 ± 4 (kJ/mol)/RT} ~D(Cr) = (1.1 ± 0.3) × 10-1 exp {-366 ± 3 (kJ/mol)/RT} and D(Ti)
= (5.6 ± 3.1) × 101 exp {-468 ± 6 (kJ/mol)/RT} The values of activation energy increase in this order: cobalt, chromium, and titanium. These
activation energies are closely related to the substitution behavior of cobalt, chromium, and titanium atoms in the Ll2 lattice sites of γ′; the cobalt atoms occupying the face-centered sites in the Ll2 structure diffuse with the normal activation energy, whereas the titanium atoms oc-cupying the cubic corner sites diffuse
with a larger activation energy that includes the energy due to local disordering caused by the atomic jumps. The chromium
atoms which can occupy both sites diffuse with an activation energy similar to that of cobalt atoms. 相似文献
129.
Toshimi Yamane Masatoshi Yasunaga Keiichi Hirao Shinsuke Yamasaki Keizo Kazama Kosei Yoshida Rikio Takeda Minoru Hiratani 《Journal of Materials Science》1988,23(1):305-310
Repetition numbers of bending of Cu-0.81 wt% Cr, Cu-0.81 wt% Cr-0.14 wt% Sn and Cu-0.26 wt% Cr-0.10 wt% Sn alloys were investigated. After solution treatment, the first two types of copper alloys have a primary chromium phase; this is not so in the last alloy. The primary chromium phase does not influence the repetition numbers of bending of cold-rolled specimens; the repetition numbers of bending of specimens aged at 723 K for 1.8 × 103 sec after cold rolling are higher than those of cold-rolled specimens. The cause of this is considered to be a recovery of work-hardening during ageing. 相似文献
130.
Since the publication of Masters and Johnson's Human Sexual Inadequacy in 1970, sex therapy has become an established, though controversial, new approach to the treatment of sexual disorders. Masters and Johnson adopted the position that any other form of psychotherapy should be avoided or suspended during the two- or three-week period of sex therapy. Helen Kaplan, in considering sex therapy to be a type of psychotherapy, has stressed that the skillful trained psychotherapist uses his awareness of the psychodynamics and unconscious conflicts of the couple in modifying and tailoring the sex therapy program to their individual needs. In the present study, sex therapy, utilizing a second therapist, was introduced into an ongoing psychoanalytic psychotherapy. 相似文献