全文获取类型
收费全文 | 992篇 |
免费 | 34篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 42篇 |
化学工业 | 208篇 |
金属工艺 | 40篇 |
机械仪表 | 19篇 |
建筑科学 | 23篇 |
能源动力 | 59篇 |
轻工业 | 117篇 |
水利工程 | 5篇 |
无线电 | 71篇 |
一般工业技术 | 148篇 |
冶金工业 | 207篇 |
原子能技术 | 22篇 |
自动化技术 | 71篇 |
出版年
2023年 | 7篇 |
2022年 | 11篇 |
2021年 | 10篇 |
2020年 | 7篇 |
2019年 | 13篇 |
2018年 | 20篇 |
2017年 | 18篇 |
2016年 | 19篇 |
2015年 | 24篇 |
2014年 | 15篇 |
2013年 | 46篇 |
2012年 | 43篇 |
2011年 | 55篇 |
2010年 | 41篇 |
2009年 | 46篇 |
2008年 | 39篇 |
2007年 | 55篇 |
2006年 | 29篇 |
2005年 | 29篇 |
2004年 | 25篇 |
2003年 | 21篇 |
2002年 | 31篇 |
2001年 | 32篇 |
2000年 | 27篇 |
1999年 | 30篇 |
1998年 | 84篇 |
1997年 | 61篇 |
1996年 | 41篇 |
1995年 | 22篇 |
1994年 | 15篇 |
1993年 | 18篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1976年 | 9篇 |
1975年 | 2篇 |
1974年 | 5篇 |
1972年 | 2篇 |
排序方式: 共有1032条查询结果,搜索用时 46 毫秒
91.
This case of ectopic pancreas found in the pre-pyloric channel of a 2-day-old infant is unique. A review of the literature reveals no other cases of symptomatic ectopic pancreas in an infant of this age. In this patient, signs and symptoms were consistent with pyloric stenosis. Upper gastrointestinal study and esophagogastroduodenoscopy (EGD) revealed the diagnosis. This case is examined and the literature is reviewed. 相似文献
92.
Morito Akiyama Hamid Reza Kokabi Kazuhiro Nonaka Kazuhisa Shobu Tadahiko Watanabe 《Journal of the American Ceramic Society》1995,78(12):3304-3308
c-axis-oriented aluminum nitride thin films were prepared on polycrystalline molybdenum disilicide substrates by rf magnetron sputtering at substrate temperatures of 50°–500°C. The films with the best orientation and crystallinity were prepared at 300°C. The dependence of film microstructure on substrate temperature was investigated by atomic force microscopy (AFM). Consequently, the microstructure changed in accordance with the model proposed by Thornton. It was found that the orientation and crystallinity of the films were optimal when the films consisted of dense fibrous grains. Further, it was confirmed that piezoelectric measurements could be made from the films during mechanical impacts. 相似文献
93.
K Ohsumi T Hatanaka K Fujita R Nakagawa Y Fukuda Y Nihei Y Suga Y Morinaga Y Akiyama T Tsuji 《Canadian Metallurgical Quarterly》1998,8(22):3153-3158
A series of cis-restricted combretastatin analogues with 5-membered heterocycles were synthesized and their inhibitory activity against microtubule assembly and cytotoxic activity against the colon 26 adenocarcinoma cancer cell line were evaluated. Some of the heterocyclic analogues showed potent antitubulin activity and cytotoxicity. Compounds 16 and 35 showed marked tumor growth suppression in the colon 26 murine tumor model. 相似文献
94.
Y Akiyama R Iwanaga T Ishikawa K Sakamoto N Nishi Z Nihei T Iwama K Saitoh Y Yuasa 《Canadian Metallurgical Quarterly》1996,78(12):2478-2484
BACKGROUND: Mutations of the transforming growth factor-beta type II receptor gene (TGF-beta RII) have been found in several replication error-positive sporadic colorectal carcinomas and hereditary nonpolyposis colorectal carcinoma cell lines. The aim of this study was to clarify the role of TGF-beta RII in sporadic colorectal carcinogenesis. METHODS: The authors screened for mutations at simple repeated sequences in the TGF-beta RII gene by polymerase chain reaction-single strand conformation polymorphism. They also examined genomic instability, using five microsatellite DNA markers in 69 sporadic colorectal carcinomas. When the carcinomas exhibited the TGF-beta RII mutations, the authors screened further for mutations in two DNA mismatch repair genes, hMSH2 and hMLH1. RESULTS: Seven of the 69 cancers (10%) showed one or two A deletions in TGF-beta RII and resultant frameshift mutations in nucleotide positions 709-718 containing a (A) 10 repeated sequence; but none of these appeared in the corresponding normal DNA, indicating a somatic mutation. All of the seven cancers were located in the proximal colon; there were none in the distal colon (P < 0.01). On the other hand, 22 of the 69 carcinomas (32%) showed the replication error-positive phenotype. The frequency of replication errors in proximal colon carcinomas was higher than that in distal colon carcinomas (P < 0.05). All 7 cancers with TGF-beta RII mutations showed replication errors. One of them revealed a nonsense mutation at codon 413, and 1 revealed a loss of heterozygosity in hMSH2. CONCLUSIONS: These data indicate that mutations of TGF-beta RII are strongly related to proximal colon carcinomas with microsatellite instability and that the mechanism of carcinogenesis in some proximal colon carcinomas is similar to that in hereditary nonpolyposis colorectal carcinoma. 相似文献
95.
Y Kajiyama M Tsurumaru H Udagawa K Tsutsumi Y Kinoshita M Ueno H Akiyama 《Canadian Metallurgical Quarterly》1998,45(23):1442-1445
BACKGROUND/AIMS: In the chemotherapy of recurrent gastric cancer with 5-fluorouracil and folinic acid, an interesting phenomenon, the reduction of jaundice and improvement of liver function, was observed. The aim of this study was to investigate the mechanism of this phenomenon, and to confirm a choleretic effect of folinic acid. METHODOLOGY: The bile duct of anesthetized rats was catheterized, and bile was collected. Bile volume and total bile acid production following intraperitoneal administration of folinic acid were determined and compared to those of control rats. RESULTS: Both bile volume and total bile acid production increased following intraabdominal administration of folinic acid. CONCLUSIONS: Folinic acid has a newly described pharmacologic effect of stimulating bile acid-dependent choleresis. It is possible that folinic acid may become a new drug for the treatment of jaundice or for the improvement of overall liver function. 相似文献
96.
K Kitabayashi T Akiyama F Tomita H Saitoh T Kosaka I Kita S Takashima 《Canadian Metallurgical Quarterly》1998,28(10):1051-1055
We report herein the unusual case of a 59-year-old woman with Plummer-Vinson syndrome who developed gastric cancer. The patient had a longstanding history of dysphagia and iron deficiency anemia, for which she had sporadically taken iron supplements that improved the dysphagia to some extent, but not completely. Owing to her tolerance of the dysphagia, she had not been taking iron supplements for the past 17 years. On admission, she was in fair nutritional condition and not anemic. Blood chemistry results were all normal, including the serum iron level. Gastrointestinal radiographic series demonstrated cervical esophageal webs and advanced gastric cancer. Her dysphagia was successfully treated by endoscopic bougienage through the webs, and a distal partial gastrectomy with nodal dissection was performed. Histology of the resected stomach revealed atrophic mucosal change and, by chance, an adenomatous lesion in addition to adenocarcinoma. Her postoperative course was uneventful and she is now well, without any signs of recurrence. Although Plummer-Vinson syndrome is known to be associated with upper alimentary tract cancers, gastric cancer is extremely rare. A discussion on the etiology of Plummer-Vinson syndrome and its link with potential carcinogenesis follows this case report. 相似文献
97.
Various types of pulse sequences for MR cholangiopancreatography (MRCP) have been developed in the past ten years. FASE (fast advanced spin echo) is one of the single-shot fast spin-echo sequences developed by Toshiba. By using this sequence, 2D single slice, 2D multiple slice and 3D methods can be provided. We routinely employ 2D single slice and 3D methods. The merit of 2D single slice method is conveniently obtained projection imaging within short data acquisition time. On the other hand, 3D method can yield detailed evaluation of various anatomical structures and abnormalities by using thin-slice source images. O2-inhalation study is especially recommended in case of 3D method. With the proper knowledge of sequence characteristics, MRCP using FASE can provide valuable informations of pancreatico-biliary diseases. 相似文献
98.
Akiyama T. Georgiev N. Mozume T. Yoshida H. Gopal A.V. Wada O. 《Photonics Technology Letters, IEEE》2002,14(4):495-497
We report on the first all-optical switching operation of intersubband absorption at an optical communication wavelength (~1.55 μm). The 1.55-μm intersubband absorption was achieved by InGaAs-AlAs-AlAsSb coupled quantum wells. A switching operation on an ultrafast signal (equivalent to 1 THz) was successfully demonstrated with a control pulse energy as low as 27 pJ 相似文献
99.
Toshihiko Hirama Masashi Goto Toshiyasu Hasegawa Minoru Kanechika Takahiro Kei Tsutomu Mieda Hiroshi Abe Katsuki Takiguchi Hiroshi Akiyama 《Nuclear Engineering and Design》2005,235(13):1128
In Japan, the Nuclear Power Engineering Corporation (NUPEC), sponsored by the Ministry of Economy, Trade and Industry (METI), has been conducting a series of seismic reliability proving tests using full-scale or close to full-scale models to simulate actual important equipment that is critical for seismic safety of nuclear power plants. The tests are intended to validate the seismic design and reliability with a sufficient margin even under destructive earthquakes. A series of tests was carried out on a reinforced concrete containment vessel (RCCV) for advanced boiling water reactor (ABWR) from 1992 to 1999. A large-scale high-performance shaking table at Tadotsu Engineering Laboratory, the largest in the world, was used for this test. Part 1 reports the test model and the results of pressure and leak tests. Part 2 describes test procedures, input waves and the results of verification tests such as changes of stiffness, characteristic frequency and damping ratio, the failure of the model and the load deflection. Part 3 shows the seismic safety margin that was evaluated from the energy input during the failure test to a design basis earthquake. Part 4 reports simulation analysis results by a stick model with lumped masses. 相似文献
100.
K Hisamatsu S Iwamori K Minami K Tanabe K Ota H Akiyama 《Canadian Metallurgical Quarterly》1997,24(10):1327-1330
A 44-year-old premenopausal woman having local recurrence and pleural and bone metastases of breast cancer was treated with aromatization inhibition in combination with Luteinizing Hormone-releasing Hormone (LH-RH) agonist. The dominant site of metastasis was a painful local lesion invading the chest wall. A partial response by reducing the size of the local lesion was attained 3 months after initiation of treatment. This result suggested that treatment using aromatization inhibition in combination with LH-RH agonist would be effective in premenopausal breast cancer. To confirm the effectiveness of this treatment, comparative study between aromatization inhibition in combination with LH-RH agonist aromatization inhibition alone and anti-estrogen in combination with LH-RH agonist are needed. 相似文献