全文获取类型
收费全文 | 3442篇 |
免费 | 30篇 |
专业分类
电工技术 | 37篇 |
综合类 | 2篇 |
化学工业 | 188篇 |
金属工艺 | 29篇 |
机械仪表 | 49篇 |
建筑科学 | 104篇 |
矿业工程 | 5篇 |
能源动力 | 45篇 |
轻工业 | 152篇 |
水利工程 | 32篇 |
石油天然气 | 9篇 |
无线电 | 155篇 |
一般工业技术 | 269篇 |
冶金工业 | 2115篇 |
原子能技术 | 22篇 |
自动化技术 | 259篇 |
出版年
2021年 | 17篇 |
2020年 | 12篇 |
2019年 | 16篇 |
2018年 | 17篇 |
2017年 | 16篇 |
2016年 | 18篇 |
2015年 | 21篇 |
2014年 | 37篇 |
2013年 | 119篇 |
2012年 | 43篇 |
2011年 | 60篇 |
2010年 | 44篇 |
2009年 | 42篇 |
2008年 | 53篇 |
2007年 | 71篇 |
2006年 | 66篇 |
2005年 | 60篇 |
2004年 | 57篇 |
2003年 | 44篇 |
2002年 | 62篇 |
2001年 | 36篇 |
2000年 | 38篇 |
1999年 | 88篇 |
1998年 | 528篇 |
1997年 | 349篇 |
1996年 | 238篇 |
1995年 | 135篇 |
1994年 | 133篇 |
1993年 | 131篇 |
1992年 | 48篇 |
1991年 | 58篇 |
1990年 | 54篇 |
1989年 | 62篇 |
1988年 | 70篇 |
1987年 | 48篇 |
1986年 | 37篇 |
1985年 | 54篇 |
1984年 | 16篇 |
1983年 | 24篇 |
1982年 | 32篇 |
1981年 | 38篇 |
1980年 | 26篇 |
1979年 | 15篇 |
1978年 | 17篇 |
1977年 | 91篇 |
1976年 | 126篇 |
1975年 | 11篇 |
1973年 | 15篇 |
1972年 | 14篇 |
1971年 | 9篇 |
排序方式: 共有3472条查询结果,搜索用时 0 毫秒
1.
Sarah Gilgunn Keefe Murphy Henning Stckmann Paul J. Conroy T. Brendan Murphy R. William Watson Richard J. OKennedy Pauline M. Rudd Radka Saldova 《International journal of molecular sciences》2020,21(23)
The diagnosis and treatment of prostate cancer (PCa) is a major health-care concern worldwide. This cancer can manifest itself in many distinct forms and the transition from clinically indolent PCa to the more invasive aggressive form remains poorly understood. It is now universally accepted that glycan expression patterns change with the cellular modifications that accompany the onset of tumorigenesis. The aim of this study was to investigate if differential glycosylation patterns could distinguish between indolent, significant, and aggressive PCa. Whole serum N-glycan profiling was carried out on 117 prostate cancer patients’ serum using our automated, high-throughput analysis platform for glycan-profiling which utilizes ultra-performance liquid chromatography (UPLC) to obtain high resolution separation of N-linked glycans released from the serum glycoproteins. We observed increases in hybrid, oligomannose, and biantennary digalactosylated monosialylated glycans (M5A1G1S1, M8, and A2G2S1), bisecting glycans (A2B, A2(6)BG1) and monoantennary glycans (A1), and decreases in triantennary trigalactosylated trisialylated glycans with and without core fucose (A3G3S3 and FA3G3S3) with PCa progression from indolent through significant and aggressive disease. These changes give us an insight into the disease pathogenesis and identify potential biomarkers for monitoring the PCa progression, however these need further confirmation studies. 相似文献
2.
14 medicated hypertensive, 15 nonmedicated mild hypertensive, 39 normotensive, and 13 hypotensive adults participated in a 1–2 hr laboratory experiment that assessed each S's symptoms, moods, and estimates of systolic blood pressure (SBP) relative to actual SBP levels. Several self-reports and autonomic measures were collected during and after each of 22 tasks. Within-S correlations indicated that all Ss could estimate SBP at levels greater than chance. Further, 68% of the Ss evidenced at least 1 significant symptom–SBP correlation. Although medicated hypertensives believed they could estimate their BP more accurately than other groups, they were actually no more accurate than the other Ss. They also evidenced far fewer empirically derived symptom–SBP and emotion–SBP correlations than any other group. Overall, blood pressure (BP) beliefs were largely inaccurate. If these erroneous beliefs can be eliminated, Ss may be able to estimate BP fluctuations more accurately. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
GW Pratt 《Canadian Metallurgical Quarterly》1997,(23):30-32
A discussion is presented of contributing factors to the injury to the foreleg of the Thoroughbred racehorse. The critical part of the step is taken to be the first 10-20 ms after ground contact as the hoof slides forward and stops. Large nonaxial loads associated with the deceleration of the hoof are shown to arise. Results of accelerometer measurements on the hoof of a horse running at racing speed are presented as well as mechanical properties of the racing surface. The mechanical properties of the track surface, the type of shoe, and the degree of fatigue of the horse all work together to determine the level of risk. 相似文献
4.
5.
For users of an executive information system (EIS), the EIS interface is the system and is crucial to the EIS's success. These guidelines for designing EIS interfaces are based on studies of actual EIS interfaces that meet the unique information needs of executives. 相似文献
6.
7.
Many current implementations of protocols such as the Transmission Control Protocol/Internet Protocol (TCP/IP) are inefficient because data are often accessed more frequently than necessary. Three techniques that reduce the need for memory bandwidth are proposed. The techniques are copy-on-write, page remapping, and single-copy. Afterburner, a network-independent card that provides the services that are necessary for a single-copy protocol stack, is described. The card has 1 MByte of local buffers and provides a simple interface to a variety of network link adapters, including HIPPI and asynchronous transfer mode (ATM). Afterburner can support transfers to and from the link adapter card at rates up to 1 Gbit/s. An implementation of TCP/IP that uses the features provided by Afterburner to reduce the movement of data to a single copy is discussed. Measurements of the end-to-end performance of Afterburner and the single-copy implementation of TCP/IP are presented 相似文献
8.
Several simple 3D experiments are used to provide J correlations between methionine C epsilon methyl carbons and either the C gamma H2 protons or C beta and C gamma. The intensity of the J correlations provides information on the size of the three-bond J couplings and thereby on the chi 3 torsion angle. In addition, a simple 3D version of the HMBC experiment provides a sensitive link between the C epsilon H3 methyl protons and C gamma. The methods are demonstrated for a 20 kDa complex between calmodulin and a 26-residue peptide fragment of skeletal muscle myosin light chain kinase. 相似文献
9.
10.
R. Watson 《Measurement》1994,13(4):267-271
The instrumentation described in this paper is designed to provide a relatively cheap and simple method of recording the changing water level during the operation of a laboratory surge tank. The method detects the passage of the water surface past a number of pairs of electrodes fitted into the side of the surge tank. One of each pair is supplied with a low D.C. voltage, so that when the pair is immersed in water, a small current flows. This signal is amplified and encoded before being used by a VELA datalogger acting as a timing device. The data is later transferred to a microcomputer for presentation in graphical and printed form. The method copes accurately both with the initial rapid large change in water level and the subsequent slowly decaying oscillations. It can also be used for automatic calibration of other methods of recording changing water levels. 相似文献