全文获取类型
收费全文 | 2457篇 |
免费 | 40篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 138篇 |
综合类 | 6篇 |
化学工业 | 618篇 |
金属工艺 | 158篇 |
机械仪表 | 35篇 |
建筑科学 | 37篇 |
能源动力 | 103篇 |
轻工业 | 119篇 |
水利工程 | 6篇 |
石油天然气 | 4篇 |
无线电 | 238篇 |
一般工业技术 | 444篇 |
冶金工业 | 376篇 |
原子能技术 | 69篇 |
自动化技术 | 157篇 |
出版年
2023年 | 7篇 |
2022年 | 12篇 |
2021年 | 31篇 |
2020年 | 16篇 |
2019年 | 12篇 |
2018年 | 24篇 |
2017年 | 21篇 |
2016年 | 30篇 |
2015年 | 24篇 |
2014年 | 46篇 |
2013年 | 120篇 |
2012年 | 60篇 |
2011年 | 125篇 |
2010年 | 78篇 |
2009年 | 117篇 |
2008年 | 104篇 |
2007年 | 76篇 |
2006年 | 91篇 |
2005年 | 84篇 |
2004年 | 53篇 |
2003年 | 62篇 |
2002年 | 77篇 |
2001年 | 70篇 |
2000年 | 59篇 |
1999年 | 65篇 |
1998年 | 171篇 |
1997年 | 67篇 |
1996年 | 85篇 |
1995年 | 68篇 |
1994年 | 73篇 |
1993年 | 45篇 |
1992年 | 48篇 |
1991年 | 52篇 |
1990年 | 44篇 |
1989年 | 38篇 |
1988年 | 29篇 |
1987年 | 25篇 |
1986年 | 38篇 |
1985年 | 26篇 |
1984年 | 32篇 |
1983年 | 42篇 |
1982年 | 22篇 |
1981年 | 26篇 |
1980年 | 19篇 |
1979年 | 24篇 |
1978年 | 19篇 |
1977年 | 7篇 |
1976年 | 13篇 |
1972年 | 8篇 |
1969年 | 4篇 |
排序方式: 共有2508条查询结果,搜索用时 0 毫秒
11.
X. J. Liu R. Kainuma I. Ohnuma K. Ishida K. Oikawa 《JOM Journal of the Minerals, Metals and Materials Society》2003,55(12):53-59
Phase diagrams and a thermodynamic database constructed by the Calculation of Phase Diagrams approach offer powerful tools
for alloy design and materials development. This article presents recent progress on the thermodynamic database for microsolders
and copper-based alloys, which is useful for the development of lead-free solders and prediction of interfacial phenomena
between solders and the copper substrate in electronic packaging technology. In addition, examples of phase diagram applications
are presented to facilitate the development of Co-Cr-based magnetic recording media in hard disks and new ferromagnetic shape-memory
alloys.
For more information, contact K. Ishida, Tohoku University, Department of Materials Science, Graduate School of Engineering,
Aoba-yama 02, Sendai 980-8579, Japan. 相似文献
12.
13.
H Ishida T Ohsawa H Nakada D Hashimoto T Ohkubo A Adachi S Itoyama 《Canadian Metallurgical Quarterly》2003,33(7):545-549
We report an unusual case of carcinosarcoma of the colon. An 80-year-old woman was admitted to our hospital with lower abdominal pain. Computed tomography showed a large pelvic mass, 18cm in maximal diameter, and barium enema and colonoscopy both showed a type-2 tumor in the sigmoid colon. We performed Hartmann's procedure with resection of the ileocolic segment. Immunohistochemical stains of the resected specimen revealed that most of the tumor consisted of spindle cell sarcoma with neural and muscle differentiation, while only the superficial area of an ulcerated lesion contained adenocarcinoma positive for carcinoembryonic antigen. The patient died of a fast-growing recurrent pelvic tumor 6 months postoperatively. Our experience of this case and our review of eight other cases in the English literature indicate that wide resection provides the best chance of cure, but careful postoperative follow-up is essential. 相似文献
14.
We constructed a probabilistic simulator that allows all the events in population dynamics such as death, birth, mutation,
and suppression/stimulation to be described by probabilistic rules. The simulator also facilitates a lattice used for expressing
distribution and diversity (number of distinct strains) of quasispecies. The simulator is used to investigate the diversity
threshold in HIV and T-cell interaction.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
15.
Recently, progress has been made in the Generalized Multi-Protocol Label Switching (GMPLS) and Automatic Switched Optical
Networks (ASON) standardizations. These technologies realize construction of large-scaled optical networks, interconnections
among single-domain Wavelength Division Multiplexing (WDM) networks, and direct communication over multi-domain WDM networks.
Meanwhile, it is known that the topology of the Internet exhibits the power-law attribute. Since the topology of the Internet,
which is constructed by interconnecting ASs, exhibits the power-law, there is a possibility that large-scale WDM networks,
which are constructed by interconnecting WDM networks, will also exhibit the power-law attribute. One of the structural properties
of a topology that adheres to the power-law is that most nodes have just a few links, although some have a tremendous number
of them. Another property is that the average distance between nodes is smaller than in a mesh-like network. A natural question
is how such a structural property performs in WDM networks. In this paper, we first investigate the property of the power-law
attribute of physical topologies for WDM networks. We compare the performance of WDM networks with mesh-like and power-law
topologies, and show that links connected to high-degree nodes are bottlenecks in power-law topologies. To relax this, we
introduce a concept of virtual fiber, which consists of two or more fibers, and propose its configuration method to utilize
wavelength resources more effectively. We compare performances of power-law networks with and without our method by computer
simulations. The results show that our method reduces the blocking probabilities by more than one order of magnitude. 相似文献
16.
17.
Seshita T. Ikeda Y. Wakimoto H. Ishida K. Terada T. Matsunaga T. Suzuki T. Kitaura Y. Uchitomi N. 《Solid-State Circuits, IEEE Journal of》1994,29(12):1583-1588
An ultrahigh-speed 8 bit multiplexer (MUX) has been developed for future-generation optical-fiber communication systems having a data rate of 20 Gb/s. This IC was fabricated using a 0.5 μm WNx/W-gate GaAs MESFET process based on optical lithography, ion implantation, and furnace annealing for good reproducibility and high throughput. The WNx/W bilayer gate has a low sheet resistance, improving the circuit high frequency performance. To attain 20 GHz operation, advanced circuit techniques for the source-coupled FET logic (SCFL) were introduced. A cross coupled source-follower (CCSF) was developed mainly for the highest speed buffers to enhance the bandwidth. The first-stage T-type flip-flop was designed with optimization techniques and operated up to 21.1 GHz 相似文献
18.
F Bigoni U Koehler R Stanyon T Ishida J Wienberg 《Canadian Metallurgical Quarterly》1997,102(3):315-327
The adhesive core of the desmosome is composed of cadherin-like glycoproteins of 2 families, desmocollins and desmogleins. The desmosomal cadherins show distinct patterns of expression in adult epidermis, and we have suggested that the desmocollins have a functional role in regulating the differentiation and/or morphogenesis of that epithelium (North et al. [1996] Proc. Natl. Acad. Sci. USA 93:7701-7705.). To examine this hypothesis, we cloned murine desmocollins and examined the induction patterns of desmocollins 1 and 3 during skin and skin appendage development. Desmocollins 3 and 1 were first expressed in epidermis in highly regional patterns at embryonic days 13.0 and 13.5, respectively, and both were up-regulated in general body epidermis at day 14.5. At this stage, epidermis is undifferentiated and the desmocollins showed an unexpected expression pattern. However, by day 18.5 when skin had undergone terminal differentiation, desmocollin 1 and 3 expression resembled that found in the adult. Thus, the establishment of the adult pattern of desmocollin expression corresponds to the adult pattern of epidermal stratification. We suggest that it is the ratio of desmocollin 1 to desmocollin 3 expression at different levels in the epidermis that is fundamental in establishing this pattern of differentiation. 相似文献
19.
J Kido C Kasahara K Ohishi S Nishikawa H Ishida K Yamashita S Kitamura K Kohri T Nagata 《Canadian Metallurgical Quarterly》1995,40(10):967-972
Osteopontin is a prominent non-collagenous component of bone matrix, although it is expressed in several other tissues. Recently, osteopontin was reported to be involved in urinary stone formation and atherosclerotic lesions of the aorta, suggesting that it may be a key protein associated with these types of pathological mineralization. In this study, whether or not human dental calculus contains osteopontin was investigated by immunoblotting and immunohistochemical analyses. After extraction of calculus proteins with EDTA and separation of the proteins by electrophoresis, immunoblotting analysis revealed the presence of osteopontin. Two forms of osteopontin appeared at 61 and 68 kDa on 10% polyacrylamide gel and the proteins were digested with thrombin, a highly specific protease. Moreover, immunohistochemical analysis revealed that osteopontin was localized in dental calculus adherent to tooth roots. These findings indicate that osteopontin is, in fact, present in human dental calculus and may be involved in calculus formation as the stone matrix. 相似文献
20.