全文获取类型
收费全文 | 1356篇 |
免费 | 76篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 12篇 |
综合类 | 5篇 |
化学工业 | 591篇 |
金属工艺 | 14篇 |
机械仪表 | 29篇 |
建筑科学 | 33篇 |
矿业工程 | 1篇 |
能源动力 | 61篇 |
轻工业 | 209篇 |
水利工程 | 9篇 |
石油天然气 | 3篇 |
无线电 | 61篇 |
一般工业技术 | 237篇 |
冶金工业 | 56篇 |
原子能技术 | 4篇 |
自动化技术 | 108篇 |
出版年
2024年 | 3篇 |
2023年 | 34篇 |
2022年 | 85篇 |
2021年 | 107篇 |
2020年 | 39篇 |
2019年 | 46篇 |
2018年 | 64篇 |
2017年 | 55篇 |
2016年 | 61篇 |
2015年 | 51篇 |
2014年 | 50篇 |
2013年 | 83篇 |
2012年 | 67篇 |
2011年 | 99篇 |
2010年 | 82篇 |
2009年 | 56篇 |
2008年 | 86篇 |
2007年 | 70篇 |
2006年 | 48篇 |
2005年 | 24篇 |
2004年 | 23篇 |
2003年 | 26篇 |
2002年 | 23篇 |
2001年 | 13篇 |
2000年 | 15篇 |
1999年 | 12篇 |
1998年 | 4篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1977年 | 6篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1970年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有1433条查询结果,搜索用时 15 毫秒
21.
Satish Kumar Vemuri Satyajit Halder Rajkiran Reddy Banala Hari Krishnreddy Rachamalla Vijaya Madhuri Devraj Chandra Shekar Mallarpu Uttam Kumar Neerudu Ravikiran Bodlapati Sudip Mukherjee Subbaiah Goli Peda Venkata Gurava Reddy Annapareddy Venkata Malarvilli Thakkumalai Kuladip Jana 《International journal of molecular sciences》2022,23(4)
Background: Breast cancer is the most common cancer in women globally, and diagnosing it early and finding potential drug candidates against multi-drug resistant metastatic breast cancers provide the possibilities of better treatment and extending life. Methods: The current study aimed to evaluate the synergistic anti-metastatic activity of Curcumin (Cur) and Paclitaxel (Pacli) individually, the combination of Curcumin–Paclitaxel (CP), and also in conjugation with gold nanoparticles (AuNP–Curcumin (Au-C), AuNP–Paclitaxel (Au-P), and AuNP–Curcumin–Paclitaxel (Au-CP)) in various in vitro and in vivo models. Results: The results from combination treatments of CP and Au-CP demonstrated excellent synergistic cytotoxic effects in triple-negative breast cancer cell lines (MDA MB 231 and 4T1) in in vitro and in vivo mouse models. Detailed mechanistic studies were performed that reveal that the anti-cancer effects were associated with the downregulation of the expression of VEGF, CYCLIN-D1, and STAT-3 genes and upregulation of the apoptotic Caspase-9 gene. The group of mice that received CP combination therapy (with and without gold nanoparticles) showed a significant reduction in the size of tumor when compared to the Pacli alone treatment and control groups. Conclusions: Together, the results suggest that the delivery of gold conjugated Au-CP formulations may help in modulating the outcomes of chemotherapy. The present study is well supported with observations from cell-based assays, molecular and histopathological analyses. 相似文献
22.
Design optimization of deep groove ball bearings using crowding distance particle swarm optimization
This paper presents a crowding distance particle swarm optimization technique to optimize the design parameters of deep groove ball bearings. The design optimization problem is multi-objective in nature. The considered objectives are maximizing dynamic and static load bearing capacities and minimizing elasto-hydrodynamic film thickness. The technique is applied to bearings used in transmission system of a tractor for the purpose of farming. Pareto optimal solutions are obtained using the proposed technique. The results obtained from the technique are found to be superior compared with NSGA-II and catalogue values. 相似文献
23.
Dr. Camila M. Crnkovic Dr. Jana Braesel Dr. Aleksej Krunic Prof. Dr. Alessandra S. Eustáquio Prof. Dr. Jimmy Orjala 《Chembiochem : a European journal of chemical biology》2020,21(6):845-852
Cyanobactins are a large family of cyanobacterial ribosomally synthesized and post-translationally modified peptides (RiPPs) often associated with biological activities, such as cytotoxicity, antiviral, and antimalarial activities. They are traditionally described as cyclic molecules containing heterocyclized amino acids. However, this definition has been recently challenged by the discovery of short, linear cyanobactins containing three to five amino acids as well as cyanobactins containing no heterocyclized residues. Herein we report the discovery of scytodecamide ( 1 ) from the freshwater cyanobacterium Scytonema sp. UIC 10036. Structural elucidation based on mass spectrometry, 1D and 2D NMR spectroscopy, and Marfey's method revealed 1 to be a linear decapeptide with an N-terminal N-methylation and a C-terminal amidation. The genome of Scytonema sp. UIC 10036 was sequenced, and bioinformatic analysis revealed a cyanobactin-like biosynthetic gene cluster consistent with the structure of 1 . The discovery of 1 as a novel linear peptide containing an N-terminal N-methylation and a C-terminal amidation expands the chemical and genetic diversity of the cyanobactin family of compounds. 相似文献
24.
25.
Forschung im Ingenieurwesen - Lkw-Überholmanöver auf Autobahnen können Konfliktsituationen provozieren. Das lange Blockieren der Überholspur und plötzliche Ausscheren kann... 相似文献
26.
Scientometrics - With an ever increasing number of academic conferences being offered and a growing concern regarding the appearance of “predatory conferencing”, the optimal use of... 相似文献
27.
We drew on the unified theory of acceptance and use of technology (UTAUT2) model, and perceived risk construct to propose an integrated model to explain continuance usage of mobile shopping applications. Espoused national cultural values of individualism/collectivism, masculinity/femininity, power distance, uncertainty avoidance, and long-term/short-term orientation act as moderators to examine the influence of within-culture variation on app usage. Findings reveal habit as the strongest predictor of both continuance intention and use behaviour, but interestingly perceived risk did not influence the post-acceptance behaviour of users significantly. Individualism/collectivism, masculinity/femininity, and long-term/short-term orientation espoused cultural values significantly moderated the relationships in the model. Noteworthy theoretical and managerial implications of the research are discussed further. 相似文献
28.
Olga Leuner Jaroslav Havlik Jana Hummelova Elena Prokudina Pavel Novy Ladislav Kokoska 《Journal of the science of food and agriculture》2013,93(3):575-579
BACKGROUND: Isoflavones and coumestrol from dietary legumes are plant constituents showing multiple beneficial effects on humans. Owing to their ability to bind with mammalian estrogenic receptors and thereby intervention in several kinds of hormone‐related cancers, they have received much attention. Soybean (Glycine max) is currently the major source of isoflavonoids in human diet. However, dozens of tropical and subtropical leguminous species remain unexplored for their isoflavonoids content. RESULTS: We have analyzed 55 extracts from 41 tropical and subtropical legume species used either in human or animal diet by high‐performance liquid chromatography for the content of soy isoflavones, biochanin A, daidzein, daidzin, formononetin, genistein, genistin, sissotrin, ononin and the coumestan coumestrol. Genistein and biochanin A were the most abundant compounds. The highest content of genistein was found in aerial parts of Andira macrothyrsa, seeds of Pachyrhizus tuberosus and aerial parts of Calopogonium mucunoides (598, 250 and 184 µg g?1, respectively) and biochanin A in aerial parts of Cratylia argentea, C. mucunoides and flowers of A. macrothyrsa (76, 53 and 40 µg g?1, respectively). CONCLUSION: None of the samples tested was richer overall source of soy isoflavones and coumestrol than soybean; nevertheless several species (C. mucunoides or A. macrothyrsa) may serve as a promising source of individual compounds. © 2012 Society of Chemical Industry 相似文献
29.
Although filial therapy has traditionally been viewed as suitable for children of diverse cultures, there is limited research to support this perspective. This qualitative case study examined the perceived effectiveness of filial therapy for a Jamaican mother and the perceived effect on the mother-child relationship. Findings indicate that some aspects of filial therapy are congruent with the parenting practices and values of this Jamaican mother. The mother reported an increase in empathy, a heightened awareness of her child's needs, and a stronger relationship with her child. She expressed some difficulty with limit setting and tracking skills taught as part of the model. Future research directions include further examination of the compatibility of filial therapy with other Jamaican parents and the effectiveness of group filial therapy with Jamaican parents or other parents of Caribbean descent. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
30.
Anna Siskova Jan Kral Jana Drabova Klara Cervena Kristyna Tomasova Jiri Jungwirth Tomas Hucl Pavel Kohout Sandra Summerova Ludmila Vodickova Pavel Vodicka Veronika Vymetalkova 《International journal of molecular sciences》2022,23(14)
A colorectal adenoma, an aberrantly growing tissue, arises from the intestinal epithelium and is considered as precursor of colorectal cancer (CRC). In this study, we investigated structural and numerical chromosomal aberrations in adenomas, hypothesizing that chromosomal instability (CIN) occurs early in adenomas. We applied array comparative genomic hybridization (aCGH) to fresh frozen colorectal adenomas and their adjacent mucosa from 16 patients who underwent colonoscopy examination. In our study, histologically similar colorectal adenomas showed wide variability in chromosomal instability. Based on the obtained results, we further stratified patients into four distinct groups. The first group showed the gain of MALAT1 and TALAM1, long non-coding RNAs (lncRNAs). The second group involved patients with numerous microdeletions. The third group consisted of patients with a disrupted karyotype. The fourth group of patients did not show any CIN in adenomas. Overall, we identified frequent losses in genes, such as TSC2, COL1A1, NOTCH1, MIR4673, and GNAS, and gene gain containing MALAT1 and TALAM1. Since long non-coding RNA MALAT1 is associated with cancer cell metastasis and migration, its gene amplification represents an important event for adenoma development. 相似文献