全文获取类型
收费全文 | 7749篇 |
免费 | 13篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 43篇 |
综合类 | 1篇 |
化学工业 | 208篇 |
金属工艺 | 29篇 |
机械仪表 | 26篇 |
建筑科学 | 44篇 |
矿业工程 | 23篇 |
能源动力 | 32篇 |
轻工业 | 99篇 |
水利工程 | 12篇 |
石油天然气 | 8篇 |
无线电 | 136篇 |
一般工业技术 | 198篇 |
冶金工业 | 6780篇 |
原子能技术 | 9篇 |
自动化技术 | 115篇 |
出版年
2022年 | 12篇 |
2018年 | 8篇 |
2017年 | 15篇 |
2016年 | 9篇 |
2015年 | 11篇 |
2014年 | 17篇 |
2013年 | 55篇 |
2012年 | 32篇 |
2011年 | 42篇 |
2010年 | 22篇 |
2009年 | 31篇 |
2008年 | 39篇 |
2007年 | 38篇 |
2006年 | 37篇 |
2005年 | 39篇 |
2004年 | 42篇 |
2003年 | 49篇 |
2002年 | 20篇 |
2001年 | 16篇 |
2000年 | 31篇 |
1999年 | 232篇 |
1998年 | 2105篇 |
1997年 | 1169篇 |
1996年 | 859篇 |
1995年 | 450篇 |
1994年 | 370篇 |
1993年 | 410篇 |
1992年 | 61篇 |
1991年 | 105篇 |
1990年 | 74篇 |
1989年 | 99篇 |
1988年 | 88篇 |
1987年 | 91篇 |
1986年 | 86篇 |
1985年 | 70篇 |
1984年 | 26篇 |
1983年 | 22篇 |
1982年 | 39篇 |
1981年 | 61篇 |
1980年 | 73篇 |
1979年 | 20篇 |
1978年 | 40篇 |
1977年 | 156篇 |
1976年 | 346篇 |
1975年 | 22篇 |
1974年 | 14篇 |
1973年 | 17篇 |
1972年 | 10篇 |
1971年 | 10篇 |
1967年 | 8篇 |
排序方式: 共有7763条查询结果,搜索用时 0 毫秒
11.
12.
13.
JL Shah 《Canadian Metallurgical Quarterly》1998,53(10):1032-1033
14.
The Internet technology known as the World Wide Web is rapidly emerging as the most powerful medium of mass communication this century and it can be harnessed to dispense global, cost-effective, high-quality, multimedia patient education material. This paper reviews how the Internet has progressed from delivering simple static, text-based material to sophisticated interactive Web sites based on CGI Technology. Interactive Web sites can be used to deliver health assessment questionnaires and Web-based decision-support systems can give patients advice on the emergency management of acute medical problems. The advantages and drawbacks of this new technology, including information regulation and quality are discussed. The role of the Hospital Intranet as a patient education resource is described. The paper concludes by illustrating how patients can appreciate the 3-D structure of bones and organs using virtual reality in a VRML Web environment. 相似文献
15.
16.
X Martinet JL L'Helgouarc'h I Roche P Favoulet P Goudet P Cougard 《Canadian Metallurgical Quarterly》1998,27(30):1534-1535
According to our common medical culture, some facts are simply unquestionable, for instance La?nnec invented the stethoscope. But was he the first one? On a recent trip to Egypt we visited the temple of Kom Ombo, built prior to the roman period and renowned as a medical care center. Today, the tourist is fascinated by the magnificent hieroglyphics on the well-preserved walls testifying to significant advances in various fields of medicine including ophthalmology and gynecology. We were particularly interested by the basreliefs presenting vivid drawings of some of the first medical instruments. We easily identified curettes, scissors, a balance, forceps for dental extraction, and a surgical saw, but were captivated by two other instruments. The first one looked a lot like what La?nnec invented around 1820. The second one was amazingly similar to the instrument we use everyday, with a distal opening and flexible tubes (woven papyrus?) leading to proximal ear pieces. Our Egyptian guide was formal: the stethoscope was invented in Egypt. The scientific impact of our observations leaves something to be desired, but did make us think about the huge gap between the advancement of medical knowledge in ancient Egypt and La?nnec's (re)-invention. Exposed to a similar gap in history, what would our documents stored on CD and video tapes have to say to future touring doctors? 相似文献
17.
JL Price 《Canadian Metallurgical Quarterly》1998,3(4):35-39
In response to a university mandate and general faculty dissatisfaction with work assignments, faculty developed a faculty work load formula. The authors discuss the development of the teaching portion of the formula. Implementation of the formula and publication of teaching work loads has resulted in greater awareness of other's responsibilities, improved faculty morale, increased accountability, and a greater sense of control. Some problem areas are also discussed. 相似文献
18.
A simple, rapid and reproducible high-performance liquid chromatographic assay for cisapride and norcisapride in human plasma is described. Samples of plasma (150 microl) were extracted using a C18 solid-phase cartridge. Regenerated tubes were eluted with 1.0 ml of methanol, dried, redissolved in 150 microl of methanol and injected. Chromatography was performed at room temperature by pumping acetonitrile-methanol-0.015 M phosphate buffer pH 2.2-2.3 (680:194:126, v/v/v) at 0.8 ml/min through a C18 reversed-phase column. Cisapride, norcisapride and internal standard were detected by absorbance at 276 nm and were eluted at 4.3, 5.3 and 8.1 min, respectively. Calibration plots in plasma were linear (r>0.998) from 10 to 150 ng/ml. Intraday precisions for cisapride and norcisapride were 3.3% and 5.4%, respectively. Interday precisions for cisapride and norcisapride were 9.6% and 9.0%, respectively. Drugs used which might be coadministered were tested for interference. 相似文献
19.
20.
Bradley James C.; Richards W.Graham 《Protein engineering, design & selection : PEDS》1994,7(7):859-862
Model structures for the pore of the potassium channels Shakerand ROMK1 are predicted. The models arise from computer simulationsand suggest reasons for the striking selectivity of these channelsfor K+ and the blocking of ROMK1 by internal Mg2+. The modelledstructure of the Shaker pore is supported by mutagenesis data.The mutagenesis experiments indicate the side chains responsiblefor binding to blocking agents [tetraethylammonium (TEA) andcharybdotoxin (CTX)] and the model has these side chains suitablyoriented for binding. An aromatic K+ binding site part way downthe pore is also predicted by the Shaker pore model. 相似文献