全文获取类型
收费全文 | 3645篇 |
免费 | 65篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 29篇 |
综合类 | 1篇 |
化学工业 | 315篇 |
金属工艺 | 32篇 |
机械仪表 | 35篇 |
建筑科学 | 55篇 |
矿业工程 | 2篇 |
能源动力 | 37篇 |
轻工业 | 157篇 |
水利工程 | 40篇 |
石油天然气 | 13篇 |
无线电 | 150篇 |
一般工业技术 | 320篇 |
冶金工业 | 2306篇 |
原子能技术 | 15篇 |
自动化技术 | 207篇 |
出版年
2023年 | 8篇 |
2022年 | 14篇 |
2021年 | 23篇 |
2020年 | 10篇 |
2019年 | 23篇 |
2018年 | 36篇 |
2017年 | 25篇 |
2016年 | 38篇 |
2015年 | 27篇 |
2014年 | 54篇 |
2013年 | 86篇 |
2012年 | 79篇 |
2011年 | 130篇 |
2010年 | 88篇 |
2009年 | 88篇 |
2008年 | 104篇 |
2007年 | 100篇 |
2006年 | 97篇 |
2005年 | 73篇 |
2004年 | 56篇 |
2003年 | 61篇 |
2002年 | 62篇 |
2001年 | 39篇 |
2000年 | 38篇 |
1999年 | 96篇 |
1998年 | 603篇 |
1997年 | 349篇 |
1996年 | 269篇 |
1995年 | 145篇 |
1994年 | 123篇 |
1993年 | 148篇 |
1992年 | 42篇 |
1991年 | 35篇 |
1990年 | 39篇 |
1989年 | 56篇 |
1988年 | 30篇 |
1987年 | 38篇 |
1986年 | 23篇 |
1985年 | 24篇 |
1983年 | 9篇 |
1982年 | 22篇 |
1981年 | 21篇 |
1980年 | 22篇 |
1979年 | 9篇 |
1978年 | 7篇 |
1977年 | 67篇 |
1976年 | 134篇 |
1975年 | 7篇 |
1974年 | 7篇 |
1973年 | 8篇 |
排序方式: 共有3714条查询结果,搜索用时 31 毫秒
1.
Belcher Calvin H. Zheng Baolong MacDonald Benjamin E. Langlois Eric D. Lehman Benjamin Pearce Charles Delaney Robert Apelian Diran Lavernia Enrique J. Monson Todd C. 《Journal of Materials Science》2022,57(9):5518-5532
Journal of Materials Science - For transformers and inductors to meet the world’s growing demand for electrical power, more efficient soft magnetic materials with high saturation magnetic... 相似文献
2.
3.
4.
5.
Degenerate oligonucleotide primers were used in a polymerase chain reaction (PCR) to amplify a region of the recA sequence of Streptococcus gordonii Challis. The resulting PCR fragment was cloned into the suicide vector pAM6199 and introduced into strain Challis, giving rise to recombination-deficient strains in which the recA gene was specifically inactivated. 相似文献
6.
Kazdin Alan E.; Bass Debra; Siegel Todd; Thomas Christopher 《Canadian Metallurgical Quarterly》1989,57(4):522
112 children (aged 7-13 yrs) were randomly assigned to one of three treatments: problem-solving skills training (PSST), problem-solving skills training with in vivo practice (PSST-P), which included therapeutically planned activities to extend training to settings outside of treatment, or client-centered relationship therapy (RT). PSST and PSST-P children showed significantly greater reductions in antisocial behavior and overall behavior problems, and greater increases in prosocial behavior than RT children. These effects were evident on measures obtained immediately after treatment and at a 1-year follow-up, and on measures of child performance at home and at school. PSST-P children showed greater changes than PSST children on measures of functioning at school at posttreatment, but these differences were no longer evident at follow-up. Children in both PSST conditions showed significant reductions in deviant behavior and improvements in prosocial behavior from pretreatment to follow-up, whereas RT children tended to remain at their pretreatment level of functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
Todd M. Alam Joshua U. Otaigbe Dave Rhoades Gregory P. Holland Brian R. Cherry Paul G. Kotula 《Polymer》2005,46(26):12468-12479
Nanostructured polymer blends prepared via anionic ring opening polymerizations of cyclic monomers in the presence of a pre-made polymer melt exhibit a number of special properties over traditional polymer blends and homopolymers. Here, we report on a simple and versatile method of in situ polymerization of macrocyclic carbonates in the presence of a maleic anhydride polypropylene (mPP) matrix and a surface-active compatibilizer (i.e. PC grafted onto a mPP backbone generated in situ) to yield a micro- and nanostructured polymer blends consisting of a polycarbonate (PC) minor phase, and a polypropylene (PP) major phase. By varying the processing conditions and concentration of the macrocyclic carbonate it was possible to reduce the size of the PC dispersions to an average minor diameter of 150 nm. NMR and TEM characterizations indicate that the PC dispersions do not influence crystal content in the PP phase. Overall, the results point to a simple strategy and versatile route to new polymeric materials with enhanced benefits. 相似文献
8.
9.
Todd R. LaPorte 《突发事故与危机管理杂志》2007,15(1):60-64
The editors of this special issue asked Todd LaPorte to reflect on the issues that emerge from the discussions in this special issue and, more in general, from the discussions that have proliferated in the wake of recent crises and disasters. In his contribution, Professor LaPorte contemplates what political leaders can do to prepare for catastrophic surprises. A crucial initiative, he argues, would be the initiation of a public discussion about the level of distress that a society is willing to accept in the pursuit of efficient, reliable critical infrastructures. 相似文献
10.
PJ Jenkins MA Satta M Simmgen WM Drake C Williamson DG Lowe K Britton SL Chew RV Thakker GM Besser 《Canadian Metallurgical Quarterly》1997,47(6):747-751
We report a patient with a metastatic parathyroid carcinoma and medullary carcinoma of the thyroid. This patient represents a variation of the multiple endocrine neoplasia syndrome (MEN) type 2A. There was no evidence of a phaeochromocytoma. The case illustrates the difficulties that may be encountered in localising the source of PTH secretion; the patient underwent four unsuccessful exploratory operations of the neck and mediastinum before further investigations revealed a single metastatic deposit of parathyroid carcinoma involving the first thoracic vertebra. PCR amplification and sequencing of the RET oncogene from the metastatic parathyroid carcinoma and genomic DNA revealed a heterozygous mutation (Cys634Tyr) in exon 11, as has previously been described to occur in MEN 2A. In addition, loss of tumour heterozygosity was demonstrated at loci from chromosomes 1, 2, 3p, 13q and 16p. This represents the first report of a parathyroid carcinoma in a MEN2A patient, in which the multiple allelic deletions are consistent with the generalised losses observed in aggressive tumours. 相似文献