全文获取类型
收费全文 | 2735篇 |
免费 | 25篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 89篇 |
综合类 | 3篇 |
化学工业 | 529篇 |
金属工艺 | 95篇 |
机械仪表 | 78篇 |
建筑科学 | 34篇 |
能源动力 | 146篇 |
轻工业 | 125篇 |
水利工程 | 10篇 |
石油天然气 | 6篇 |
无线电 | 349篇 |
一般工业技术 | 445篇 |
冶金工业 | 661篇 |
原子能技术 | 45篇 |
自动化技术 | 156篇 |
出版年
2023年 | 12篇 |
2022年 | 18篇 |
2021年 | 45篇 |
2020年 | 17篇 |
2019年 | 17篇 |
2018年 | 17篇 |
2017年 | 23篇 |
2016年 | 30篇 |
2015年 | 28篇 |
2014年 | 47篇 |
2013年 | 116篇 |
2012年 | 73篇 |
2011年 | 109篇 |
2010年 | 91篇 |
2009年 | 92篇 |
2008年 | 101篇 |
2007年 | 99篇 |
2006年 | 75篇 |
2005年 | 59篇 |
2004年 | 62篇 |
2003年 | 102篇 |
2002年 | 72篇 |
2001年 | 63篇 |
2000年 | 44篇 |
1999年 | 85篇 |
1998年 | 311篇 |
1997年 | 173篇 |
1996年 | 108篇 |
1995年 | 70篇 |
1994年 | 82篇 |
1993年 | 70篇 |
1992年 | 38篇 |
1991年 | 34篇 |
1990年 | 45篇 |
1989年 | 33篇 |
1988年 | 23篇 |
1987年 | 26篇 |
1986年 | 25篇 |
1985年 | 31篇 |
1984年 | 23篇 |
1983年 | 30篇 |
1982年 | 16篇 |
1981年 | 14篇 |
1980年 | 23篇 |
1979年 | 13篇 |
1978年 | 11篇 |
1977年 | 12篇 |
1976年 | 21篇 |
1975年 | 10篇 |
1974年 | 10篇 |
排序方式: 共有2771条查询结果,搜索用时 15 毫秒
991.
E Otsuji T Yamaguchi N Yamaoka T Kotani H Tsurumi K Kitamura N Yamaguchi T Takahashi 《Canadian Metallurgical Quarterly》1993,53(3):168-174
Much recent research has been directed toward the use of monoclonal antibodies (MoAbs) for the immunodetection of solid tumors. In pancreatic cancer, conventional immunoscintigraphy using intact MoAbs remains disappointing. In this study, 125I-labeled F(ab')2 fragments produced by pepsin digestion of MoAb A7 were injected intravenously into nude mice bearing human pancreatic cancer, HPC-YS, xenografts that have previously been shown to react specifically with MoAb A7. The tumor tissue/blood ratio of 125I-labeled F(ab')2 fragments of MoAb A7 increased with time and was much higher than those for normal tissues. Moreover, the tumor tissue/blood ratio of 125I-labeled F(ab')2 fragments was greater than that of intact MoAb A7, although the F(ab')2 accumulation was less than that of intact MoAb A7 in the tumor. These results suggest that F(ab')2 fragments of MoAb A7 may be suitable carriers of radionuclides for immunodetection of human pancreatic cancer. 相似文献
992.
T Yamamura S Tsukikawa O Akaishi K Tanaka H Matsuoka A Hanai H Oikawa T Ozasa K Kikuchi H Matsuzaki S Yamaguchi 《Canadian Metallurgical Quarterly》1997,40(12):1425-1429
PURPOSE: It frequently is observed that widely varying prognoses are given for patients with the same extent of liver metastases from colorectal cancer, even though the same treatment is performed on these patients. One of the reasons for this variance is that prognostic factors for these patients have not been defined. This study was designed to elucidate which clinicopathologic factors were the most important in the prognosis of 73 patients with unresectable synchronous liver metastasis from colorectal cancer. METHODS: Univariate and multivariate analysis of 11 clinicopathologic factors were performed using the Cox proportional hazard model. Survival curves were generated using the Kaplan-Meier method. RESULTS: Extent of liver metastases was the most significant variable in this survival analysis, although the extent of lymph node metastases of the primary lesion also was significant. However, the method of treatment was not a significant determinant in the survival for patients with unresectable liver metastases. Median survival of patients with H1, H2, and H3 was 13, 12, and 6 months, respectively, and there was a significant difference between survival curves for patients with H1 and patients with H3. Median survival of patients with n0, n1, and n2 was 13, 7, and 7 months respectively, and there was a significant difference between survival curves for patients with n0 and patients with n2. Median survival of 6 patients with H1 and n0 and of 17 patients with H3 and n2 was 28 and 4 months, respectively. There was a significant difference in survival curves between these two groups. CONCLUSION: Longevity of patients with unresectable synchronous liver metastases from colorectal cancer is affected adversely by the presence of nodal metastases and extent of liver metastases. This should be considered in the planning treatment. 相似文献
993.
Seismic PSA was carried out for a typical liquid metal cooled fast breeder reactor (LMFBR) in order to study the rationalized seismic design, maintaining and/or improving safety during seismic event. The seismic sequence quantification identifies the dominant structures, systems and components (SSCs) to the seismic core damage frequency (CDF). The sensitivity analyses by reducing or increasing the seismic capacity for SSCs are used to examine the optimized seismic design in view of safety and economical aspects. The LMFBR-specific risk-significant SSCs are reactor coolant boundary, decay heat removal coolant path and reactor control rod, which are different from those of light water reactors (LWRs). The electrical power supply system has a minor contribution to the seismic CDF. The sensitivity study shows that passive safety features of LMFBRs are important to maintain and/or enhance seismic capacity. The passive safety includes the decay heat removal capability via natural circulation and safety measures without depending on the support systems such as alternating current (AC) electrical power, for example. On the course of seismic sequence quantification, a methodology to evaluate the probability of seismic-induced multiple failure has been developed and applied to the decay heat removal function. The results suggest the multiplicity of the triply redundant system is to be considered for the significant components such as the decay heat removal path when one considers the difference in the seismic response. 相似文献
994.
H Ueda K Yoshikawa T Hashimoto T Yamaguchi T Dousei A Moriguchi M Taniguchi S Taketani K Kawano T Tsujimura 《Canadian Metallurgical Quarterly》1996,93(2):120-125
Although the overall survival rates for patients with metastatic non-small cell lung cancer have not changed in the past two decades, meta-analytic studies have confirmed that a modest increase in mean survival time can be gained with platinum-based combination chemotherapy. With appropriate selection of patients, chemotherapy will have symptomatic benefits in more than 60% of patients, and concerns regarding the costs of chemotherapy will be lessened by the observation that in some instances chemotherapy is less costly than best supportive care. Until the end of the 1980s, apart from the few active agents and their analogues no new drugs became available, but in the past 5 years several new agents have shown promising results and are now being included in combination programs. Large-scale comparative studies, looking for the combination with the best therapeutic index, are awaited with great interest. The number of patients with non-small cell lung cancer is so great that even modest improvements in therapy will have a great impact on survival rates. 相似文献
995.
K Ohashi T Yamada T Ishikawa S Yamaguchi H Nakajima M Takagi 《Canadian Metallurgical Quarterly》1996,25(4):388-390
An increase in parasitaemia is not uncommon after initiation of treatment for Plasmodium falciparum malaria, but its exact significance is unknown. The time-course of parasitaemia was assessed retrospectively in 33 patients with severe imported malaria. In 19 patients (group 1) mean parasitaemia (+/- SEM) fell promptly after starting quinine treatment, from 24.9 +/- 4.1% on day 0 to 9.7 +/- 2.3% on day 1 and 1.8 +/- 0.7% on day 2. In 14 other patients (group 2), parasitaemia did not change significantly or increased, with mean parasitaemia (+/- SEM) of 9.5 +/- 2.1% on day 0, 17.2 +/- 2.6% on day 1, and 3.7 +/- 1.8% on day 2. Simplified acute physiology scores on admission (mean +/- SEM) were 17.4 +/- 1.4 in group 1 and 11.7 +/- 1.0 in group 2 (P = 0.006). The mean number of complications of malaria per patient (+/- SEM) was 2.9 +/- 0.5 in group 1 and 1.6 +/- 0.3 in group 2 (P = 0.046). Two group 1 patients died. Initially, more than 95% of peripheral blood parasites were tiny and small rings in both groups, and this distribution was unchanged on day 1, suggesting that the parasitaemia increase in group 2 was not due to release of sequestered mature parasites. In severe falciparum malaria, a rise in parasitaemia after treatment initiation may be of favourable prognostic significance and should not lead to aggressive therapeutic approaches such as exchange transfusion. 相似文献
996.
997.
Fujio Yamaguchi 《The Visual computer》1987,3(2):88-97
Theories of the 4×4 determinant method to resolve interference problems are described, in detail, in succession to the former paper [1]. First, various cases of the 4×4 determinant are discussed including the geometric implications by deriving a few fundamental relations. Secondly, normalization of the determinant is proposed. Thirdly, an intersection formula in homogeneous coordinates is verified which makes it possible to do consistent homogenous coordinate processing from the very beginning of geometric modelling to the very last of the objects displayed. Lastly an outline of how the 4×4 determinant method is applied to basic geometric problems is described.This article will provide, theoretical foundations for the 4×4 determinant method in computer graphics and geometric modelling. 相似文献
998.
K Koizumi M Yamaguchi K Tooyama G Uchiyama Y Yamada A Ueno 《Canadian Metallurgical Quarterly》1994,31(1):17-25
In rat anterior pituitary tumour cells (GH3/B6) thyrotropin-releasing hormone (TRH) elicits a biphasic response. First, a release of intracellularly stored Ca2+ induces a hyperpolarization of the cell. Second, a depolarization thought to be induced by a reduction of the inward-rectifying K+ current (KIR) causes an increase in action potential frequency and a plateau-like increase in [Ca2+]i. It has been proposed that the two phases are induced by the actions of inositol 1,4,5-trisphosphate (InsP3) and protein kinase C (PKC), respectively, but we demonstrate here that PKC is not responsible for the second phase increase in [Ca2+]i and suggest that the pathways diverge at the level of receptor and G protein coupling. Both phases of the TRH response were insensitive to pertussis toxin, but cholera toxin (CTX) selectively affected the second phase. After CTX pretreatment cells had a high spontaneous spiking frequency and smaller KIR amplitude. In these cells TRH failed to increase the action potential frequency after the first phase hyperpolarization, elicited only a transient peak increase in [Ca2+]i with no plateau phase and could only slightly reduce KIR. These effects of CTX are not mediated by its ability to increase cAMP via activation of GS, as increased cAMP levels neither inhibit KIR nor prevent its reduction by TRH. In addition, inhibition of protein kinase A activation did not block the second phase increase in [Ca2+]i induced by TRH, suggesting that the CTX-sensitive G protein mediating the second phase of the TRH response is not GS. 相似文献
999.
C Mochida Y Hirakata J Matsuda F Iori Y Ozaki M Nakano K Hamaguchi K Izumikawa T Yamaguchi K Tomono S Maesaki Y Yamada S Kohno S Kamihira 《Canadian Metallurgical Quarterly》1998,36(6):1790-1792
MICs of antibiotics against Bilophila wadsworthia isolates were measured by agar and broth microdilution with pyruvic acid and by Etest. The inoculum size influenced greatly agar dilution. Despite discrepancies in MICs depending on the measurement method used, clindamycin consistently showed potent activity. Broth microdilution and Etest appear to be candidates for laboratory susceptibility testing. 相似文献
1000.
Titanium, a metal with superior sea water corrosion resistance, is increasingly used in titanium clad steel applications for ocean structures. Titanium clad steel is normally manufactured by hot rolling or explosive deposition. Joining of titanium and iron leads to the formation of hard and brittle intermetallic compounds that impair the bond strength. It is therefore necessary to use an insert metal to suppress the occurrence of these compounds, particularly during rolling.1-3 相似文献