全文获取类型
收费全文 | 32029篇 |
免费 | 1474篇 |
国内免费 | 35篇 |
专业分类
电工技术 | 336篇 |
综合类 | 56篇 |
化学工业 | 6969篇 |
金属工艺 | 597篇 |
机械仪表 | 577篇 |
建筑科学 | 1882篇 |
矿业工程 | 77篇 |
能源动力 | 873篇 |
轻工业 | 2707篇 |
水利工程 | 295篇 |
石油天然气 | 165篇 |
武器工业 | 3篇 |
无线电 | 2286篇 |
一般工业技术 | 5918篇 |
冶金工业 | 5227篇 |
原子能技术 | 205篇 |
自动化技术 | 5365篇 |
出版年
2023年 | 277篇 |
2022年 | 447篇 |
2021年 | 700篇 |
2020年 | 504篇 |
2019年 | 593篇 |
2018年 | 723篇 |
2017年 | 692篇 |
2016年 | 907篇 |
2015年 | 813篇 |
2014年 | 1029篇 |
2013年 | 1921篇 |
2012年 | 1670篇 |
2011年 | 2125篇 |
2010年 | 1510篇 |
2009年 | 1465篇 |
2008年 | 1763篇 |
2007年 | 1647篇 |
2006年 | 1442篇 |
2005年 | 1228篇 |
2004年 | 1094篇 |
2003年 | 946篇 |
2002年 | 912篇 |
2001年 | 543篇 |
2000年 | 523篇 |
1999年 | 534篇 |
1998年 | 496篇 |
1997年 | 453篇 |
1996年 | 463篇 |
1995年 | 439篇 |
1994年 | 426篇 |
1993年 | 431篇 |
1992年 | 384篇 |
1991年 | 229篇 |
1990年 | 320篇 |
1989年 | 321篇 |
1988年 | 271篇 |
1987年 | 297篇 |
1986年 | 286篇 |
1985年 | 306篇 |
1984年 | 268篇 |
1983年 | 256篇 |
1982年 | 240篇 |
1981年 | 210篇 |
1980年 | 175篇 |
1979年 | 182篇 |
1978年 | 165篇 |
1977年 | 135篇 |
1976年 | 124篇 |
1975年 | 134篇 |
1974年 | 109篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
962.
963.
Tracey MacTavish Marie-Odile Marceau Michael Optis Kara Shaw Peter Stephenson Peter Wild 《Journal of Housing and the Built Environment》2012,27(2):207-224
First Nation (Indigenous) on-reserve housing in Canada is in crisis due to severe shortages, high reported instances of mould contamination, overcrowding and structural deficiencies. The Kitamaat reserve of the Haisla First Nation provides one example. The intent of the study reported here was to engage with the Haisla to develop a culturally appropriate, environmentally responsive and energy-efficient housing type that the Haisla could implement in the future. This work was undertaken by Marceau-Evans-Johnson Architects in collaboration with researchers at the University of Victoria. In this article, the circumstances leading to the present housing crisis are reviewed, the consultative design process with the Haisla and its outcomes are described, and the concept design solution which was co-developed for future housing is presented. 相似文献
964.
M. Berkan Sesen Michael D. Peake Rene Banares-Alcantara Donald Tse Timor Kadir Roz Stanley Fergus Gleeson Michael Brady 《Journal of the Royal Society Interface》2014,11(98)
Multidisciplinary team (MDT) meetings are becoming the model of care for cancer patients worldwide. While MDTs have improved the quality of cancer care, the meetings impose substantial time pressure on the members, who generally attend several such MDTs. We describe Lung Cancer Assistant (LCA), a clinical decision support (CDS) prototype designed to assist the experts in the treatment selection decisions in the lung cancer MDTs. A novel feature of LCA is its ability to provide rule-based and probabilistic decision support within a single platform. The guideline-based CDS is based on clinical guideline rules, while the probabilistic CDS is based on a Bayesian network trained on the English Lung Cancer Audit Database (LUCADA). We assess rule-based and probabilistic recommendations based on their concordances with the treatments recorded in LUCADA. Our results reveal that the guideline rule-based recommendations perform well in simulating the recorded treatments with exact and partial concordance rates of 0.57 and 0.79, respectively. On the other hand, the exact and partial concordance rates achieved with probabilistic results are relatively poorer with 0.27 and 0.76. However, probabilistic decision support fulfils a complementary role in providing accurate survival estimations. Compared to recorded treatments, both CDS approaches promote higher resection rates and multimodality treatments. 相似文献
965.
966.
967.
968.
Diana Nanova Sebastian Beck Andreas Fuchs Tobias Glaser Christian Lennartz Wolfgang Kowalsky Annemarie Pucci Michael Kroeger 《Organic Electronics》2012,13(7):1237-1244
The degree of charge transfer in thin films of organic charge transfer (CT)-complexes, which are deposited via thermal evaporation, is examined via infrared-spectroscopy. We demonstrate a linear relationship between the shift in the excitation energy of the CN-stretching mode of CT-complexes with the acceptor 7,7,8,8-tetracyanoquinodimethane (TCNQ) and the charge transfer. The measured correlation corresponds very well with DFT calculations. For Na-TCNQ we observe a splitting in the peak of the CN-stretching mode, which can be explained by the coupling of two modes and was confirmed by the calculations. In CT-complexes with partial charge transfer the appearance of an electronic excitation is demonstrated. 相似文献
969.
Michael Heethoff 《Journal of chemical ecology》2012,38(9):1116-1123
Most oribatid mites possess a pair of opisthonotal exocrine glands that produce mostly complex, species-specific secretions. Such blends may contain more than 10 different compounds, but hardly anything is known about their primary biosynthesis or regeneration. I analyzed recovery of the 6 main components from the 11-compound secretion of the oribatid mite Archegozetes longisetosus Aoki, including the main chemical classes hydrocarbons, aromatics, and terpenes, during a 20-day time course after complete gland depletion. About 10?% of the original total secretion amount was restored after 24?hr, and after 2–6?days, the amount had reached the range of total amount observed in the control group. Most compounds were recovered at similar rates within the first 48?hr. An important exception was pentadecane, which was predominantly produced in the first few hours, suggesting that this compound is the main solvent of the secretion. Although relative amounts of the main compounds differed significantly over time, the complex profile of the whole secretion was stable and not confidently distinguishable among the sampling dates. The general recovery rate was high during the first 48?hr, about 25 times higher than in the remaining 18?days. The biological importance of this high initial investment was supported by predation experiments: the predacious rove beetle Stenus juno was first repelled after 48?hr when at least 25?% of secretions was restored. 相似文献
970.