全文获取类型
收费全文 | 5636篇 |
免费 | 236篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 68篇 |
综合类 | 2篇 |
化学工业 | 847篇 |
金属工艺 | 98篇 |
机械仪表 | 67篇 |
建筑科学 | 310篇 |
矿业工程 | 41篇 |
能源动力 | 147篇 |
轻工业 | 575篇 |
水利工程 | 43篇 |
石油天然气 | 32篇 |
武器工业 | 3篇 |
无线电 | 560篇 |
一般工业技术 | 848篇 |
冶金工业 | 1061篇 |
原子能技术 | 52篇 |
自动化技术 | 1123篇 |
出版年
2023年 | 41篇 |
2022年 | 44篇 |
2021年 | 122篇 |
2020年 | 80篇 |
2019年 | 119篇 |
2018年 | 156篇 |
2017年 | 133篇 |
2016年 | 178篇 |
2015年 | 134篇 |
2014年 | 179篇 |
2013年 | 349篇 |
2012年 | 252篇 |
2011年 | 312篇 |
2010年 | 216篇 |
2009年 | 215篇 |
2008年 | 271篇 |
2007年 | 237篇 |
2006年 | 214篇 |
2005年 | 174篇 |
2004年 | 158篇 |
2003年 | 134篇 |
2002年 | 158篇 |
2001年 | 74篇 |
2000年 | 85篇 |
1999年 | 99篇 |
1998年 | 248篇 |
1997年 | 169篇 |
1996年 | 150篇 |
1995年 | 85篇 |
1994年 | 100篇 |
1993年 | 95篇 |
1992年 | 67篇 |
1991年 | 48篇 |
1990年 | 66篇 |
1989年 | 62篇 |
1988年 | 38篇 |
1987年 | 43篇 |
1986年 | 40篇 |
1985年 | 49篇 |
1984年 | 62篇 |
1983年 | 36篇 |
1982年 | 30篇 |
1981年 | 28篇 |
1980年 | 38篇 |
1979年 | 30篇 |
1978年 | 24篇 |
1977年 | 36篇 |
1976年 | 55篇 |
1975年 | 24篇 |
1973年 | 26篇 |
排序方式: 共有5877条查询结果,搜索用时 0 毫秒
1.
2.
Esteban Vera Pingitore María Silvina Juárez Tomás Birgitt Wiese 《Drug development and industrial pharmacy》2015,41(6):942-952
Context: The administration of pharmabiotics is a promising alternative to antimicrobial drugs for the treatment and/or prevention of female urogenital infections.Objective: To design pharmabiotic formulations including bioactive ingredients of microbial origin combined with non-microbial substances and then to evaluate the stability of the combinations during freeze-drying and storage.Materials and methods: Different formulations including Lactobacillus gasseri CRL 1263, Lactobacillus salivarius CRL 1328, salivaricin CRL 1328 (a bacteriocin) and non-microbial compounds (lactose, inulin and ascorbic acid) were assayed, and the ingredients were freeze-dried together or separately. The formulations were stored in gelatin capsules at 4?°C for 360?d.Results: The viability of lactobacilli was affected to different extents depending on the strains and on the formulations assayed. L. salivarius and ascorbic acid were successfully combined only after the freeze-drying process. Salivaricin activity was not detected in formulations containing L. gasseri. However, when combined with ascorbic acid, lactose, inulin or L. salivarius, the bacteriocin maintained its activity for 360?d. The selected microorganisms proved to be compatible for their inclusion in multi-strain formulations together with lactose, inulin and ascorbic acid. Salivaricin could be included only in a L. salivarius CRL 1328 single-strain formulation together with non-microbial substances.Conclusions: This study provides new insights into the design of urogenital pharmabiotics combining beneficial lactobacilli, salivaricin CRL 1328 and compounds with different functionalities. 相似文献
3.
4.
5.
We propose a standardization procedure that provides a convenient, quantitative and reproducible laboratory-based method for measuring the state of polarization (SOP) fluctuations produced by polarization varying devices. This method is based on the SOP distributions generated by commercial polarization scramblers. We show that these devices generate distributions of the maximum change of the SOP (in a given sample time) that follow Rayleigh statistics, which scale linearly with scrambling frequency and the sample time. We use this procedure to measure the SOP fluctuations in a short length of coiled fiber subject to mechanical perturbations. 相似文献
6.
KJ Shon M Grilley R Jacobsen GE Cartier C Hopkins WR Gray M Watkins DR Hillyard J Rivier J Torres D Yoshikami BM Olivera 《Canadian Metallurgical Quarterly》1997,36(31):9581-9587
A paralytic peptide, psi-conotoxin Piiie has been purified and characterized from Conus purpurascens venom. Electrophysiological studies indicate that the peptide inhibits the nicotinic acetylcholine receptor (nAChR). However, the peptide does not block the binding of alpha-bungarotoxin, a competitive nAChR antagonist. Thus, psi-conotoxin Piiie appears to inhibit the receptor at a site other than the acetylcholine-binding site. As ascertained by sequence analysis, mass spectrometry, and chemical synthesis, the peptide has the following covalent structure: HOOCCLYGKCRRYOGCSSASCCQR* (O = 4-trans hydroxyproline; * indicates an amidated C-terminus). The disulfide connectivity of the toxin is unrelated to the alpha- or the alphaA-conotoxins, the Conus peptide families that are competitive inhibitors of the nAChR, but shows homology to the mu-conotoxins (which are Na+ channel blockers). 相似文献
7.
Tom Mariano 《集成电路应用》2008,(11):25-25
在近期一次SEMI产业策略论坛发表的演讲中,Lam Research Corp.的总裁兼CEO Stephen Newberry认为,半导体产业已经进入了“无利的繁荣时代”。2003年以来,每比特/功能的价格已经比每比特/价格的成本下降得更快,使得整个产业的利润遭到侵蚀。这似乎成为了一个无法维继的市场,随着时间的推移必须进行自我修正才行。 相似文献
8.
9.
Formaldehyde is used in ruminant feeding for different purposes including the protection of dietary proteins from ruminal degradation. The formaldehyde content of milk of goats fed various levels of formaldehyde-treated soybean oil-meal has been determined by using a sensitive HPLC method. Results showed a significant linear correlation between ingested formaldehyde and formaldehyde concentration in milk. About 0.02% of ingested formaldehyde was excreted in milk, as free formaldehyde. 相似文献
10.