全文获取类型
收费全文 | 1774篇 |
免费 | 63篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 18篇 |
综合类 | 3篇 |
化学工业 | 479篇 |
金属工艺 | 27篇 |
机械仪表 | 32篇 |
建筑科学 | 80篇 |
矿业工程 | 1篇 |
能源动力 | 41篇 |
轻工业 | 171篇 |
水利工程 | 15篇 |
石油天然气 | 1篇 |
无线电 | 118篇 |
一般工业技术 | 295篇 |
冶金工业 | 306篇 |
原子能技术 | 25篇 |
自动化技术 | 226篇 |
出版年
2023年 | 24篇 |
2022年 | 35篇 |
2021年 | 42篇 |
2020年 | 30篇 |
2019年 | 28篇 |
2018年 | 39篇 |
2017年 | 31篇 |
2016年 | 49篇 |
2015年 | 43篇 |
2014年 | 45篇 |
2013年 | 78篇 |
2012年 | 73篇 |
2011年 | 90篇 |
2010年 | 69篇 |
2009年 | 72篇 |
2008年 | 69篇 |
2007年 | 62篇 |
2006年 | 58篇 |
2005年 | 38篇 |
2004年 | 37篇 |
2003年 | 42篇 |
2002年 | 38篇 |
2001年 | 33篇 |
2000年 | 25篇 |
1999年 | 31篇 |
1998年 | 98篇 |
1997年 | 62篇 |
1996年 | 58篇 |
1995年 | 30篇 |
1994年 | 37篇 |
1993年 | 20篇 |
1992年 | 18篇 |
1991年 | 18篇 |
1990年 | 16篇 |
1989年 | 11篇 |
1988年 | 16篇 |
1987年 | 18篇 |
1986年 | 12篇 |
1985年 | 16篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 12篇 |
1979年 | 15篇 |
1978年 | 22篇 |
1977年 | 18篇 |
1976年 | 24篇 |
1975年 | 9篇 |
1974年 | 9篇 |
1973年 | 11篇 |
排序方式: 共有1838条查询结果,搜索用时 15 毫秒
61.
Elisabeth Koch Mustafa Bagci Michael Kuhn Nicole M. Hartung Malwina Mainka Katharina M. Rund Nils Helge Schebb 《Lipids》2023,58(1):41-56
Oxysterols play a key role in many (patho)physiological processes and they are potential biomarkers for oxidative stress in several diseases. Here we developed a rapid gas chromatographic-mass spectrometry-based method for the separation and quantification of 11 biologically relevant oxysterols bearing hydroxy, epoxy, and dihydroxy groups. Efficient chromatographic separation (resolution ≥ 1.9) was achieved using a medium polarity 35%-diphenyl/65%-dimethyl polysiloxane stationary phase material (30 m × 0.25 mm inner diameter and 0.25 μm film thickness). Based on thorough analysis of the fragmentation during electron ionization we developed a strategy to deduce structural information of the oxysterols. Optimized sample preparation includes (i) extraction with a mixture of n-hexane/iso-propanol, (ii) removal of cholesterol by solid phase extraction with unmodified silica, and (iii) trimethylsilylation. The method was successfully applied on the analysis of brain samples, showing consistent results with previous studies and a good intra- and interday precision of ≤20%. Finally, we used the method for the investigation of oxysterol formation during oxidative stress in HepG2 cells. Incubation with tert-butyl hydroperoxide led to a massive increase in free radical formed oxysterols (7-keto-chol > 7β-OH-chol >> 7α-OH-chol), while 24 h incubation with the glutathione peroxidase 4 inhibitor RSL3 showed no increase in oxidative stress based on the oxysterol pattern. Overall, the new method described here enables the robust analysis of a biologically meaningful pattern of oxysterols with high sensitivity and precision allowing us to gain new insights in the biological formation and role of oxysterols. 相似文献
62.
Alexander Mundstock Ulrike Böhme Benjamin Barth Prof. Martin Hartmann Prof. Jürgen Caro 《化学,工程师,技术》2013,85(11):1694-1699
The metal‐organic framework Mg2(dhtp) with the linker dihydroxyterephthalate is known as MOF‐74 or CPO‐27. Mg2(dhtp) has been synthesized as powder to measure breakthrough curves in a fixed‐bed adsorber and adsorption isotherms, and as a supported thin membrane layer for permeation studies. The measurement of the breakthrough curves of the binary propylene/propane mixture shows that separation with the fixed bed adsorber is possible. Propylene shows a higher affinity to Mg2(dhtp). Although the single gas propane flux is slightly higher than the one of propylene, the binary propane/propylene mixture is not separated. 相似文献
63.
Analysis of Transcriptional Regulation of the Human miR-17-92 Cluster; Evidence for Involvement of Pim-1 总被引:1,自引:0,他引:1
64.
Ramona Erber Steffen Spoerl Andreas Mamilos Rosemarie Krupar Arndt Hartmann Matthias Ruebner Juergen Taxis Mareike Wittenberg Torsten E. Reichert Gerrit Spanier Silvia Spoerl 《International journal of molecular sciences》2022,23(1)
Oral cancer often presents with aggressive behavior and a high risk of recurrence and metastasis. For oral squamous cell carcinoma (OSCC), which is the most frequent histological subtype, therapy strategies include surgery, radiation therapy, chemotherapy, immune checkpoint inhibitors, and EGFR inhibitors. Recently, a Trop-2 antibody-drug conjugate (ADC) has been approved in the United States of America for the treatment of advanced triple-negative breast cancer. However, this ADC has also been tested in other solid tumors including head & neck squamous cell carcinoma. The prognostic impact of Trop-2 has already been reported for several cancers. We studied the prognostic influence of Trop-2 protein expression on OSCC patients’ survival. The cohort comprised n = 229 OSCC patients with available archived tumor tissue and corresponding non-neoplastic oral mucosa tissue. Using immunohistochemistry, we investigated Trop-2 expression in both the central and peripheral regions of each tumor and in corresponding non-neoplastic oral mucosa. In patients suffering from OSCC with combined high central and low peripheral Trop-2 expression, five-year overall survival (OS) was 41.2%, whereas 55.6% of OSCC patients who presented lower central and/or higher peripheral tumoral Trop-2 expression were alive after five years (p = 0.075). In multivariate Cox regression, the expression pattern of high central tumoral and lower peripheral Trop-2 expression was significantly correlated with impaired OS (HR = 1.802, 95%-CI: 1.134–2.864; p = 0.013) and recurrence-free survival (RFS) (HR = 1.633, 95%-CI: 1.042–2.560; p = 0.033), respectively, when adjusting for co-variables. Hence, Trop-2 may serve as an independent prognostic biomarker in OSCC. In subsequent studies, the pathophysiological meaning of downregulated Trop-2 expression in the OSCC periphery has to be analyzed. 相似文献
65.
Cover Picture: Development of Potent and Metabolically Stable APJ Ligands with High Therapeutic Potential (ChemMedChem 21/2016) 下载免费PDF全文
66.
67.
Rubber materials filled with reinforcing fillers display nonlinear rheological behavior at small strain amplitudes below γ0 < 0.1. Nevertheless, rheological data are analyzed mostly in terms of linear parameters, such as shear moduli (G′, G″), which loose their physical meaning in the nonlinear regime. In this work styrene butadiene rubber filled with carbon black (CB) under large amplitude oscillatory shear (LAOS) is analyzed in terms of the nonlinear parameter I3/1. Three different CB grades are used and the filler load is varied between 0 and 70 phr. It is found that I3/1(φ) is most sensitive to changes of the total accessible filler surface area at low strain amplitudes (γ0 = 0.32). The addition of up to 70 phr CB leads to an increase of I3/1(φ) by a factor of more than ten. The influence of the measurement temperature on I3/1 is pronounced for CB levels above the percolation threshold.
68.
Lennard Karsten Nils Janson Vadim Le Joncour Sarfaraz Alam Benjamin Müller Jayendrakishore Tanjore Ramanathan Pirjo Laakkonen Norbert Sewald Kristian M. Müller 《International journal of molecular sciences》2022,23(5)
Epidermal growth factor receptor (EGFR) is a validated tumor marker overexpressed in various cancers such as squamous cell carcinoma (SSC) of the head and neck and gliomas. We constructed protein-drug conjugates based on the anti-EGFR Designed Ankyrin Repeat Protein (DARPin) E01, and compared the bivalent DARPin dimer (DD1) and a DARPin-Fc (DFc) to the monomeric DARPin (DM) and the antibody derived scFv425-Fc (scFvFc) in cell culture and a mouse model. The modular conjugation system, which was successfully applied for the preparation of protein-drug and -dye conjugates, uses bio-orthogonal protein-aldehyde generation by the formylglycine-generating enzyme (FGE). The generated carbonyl moiety is addressed by a bifunctional linker with a pyrazolone for a tandem Knoevenagel reaction and an azide for strain-promoted azide-alkyne cycloaddition (SPAAC). The latter reaction with a PEGylated linker containing a dibenzocyclooctyne (DBCO) for SPAAC and monomethyl auristatin E (MMAE) as the toxin provided the stable conjugates DD1-MMAE (drug-antibody ratio, DAR = 2.0) and DFc-MMAE (DAR = 4.0) with sub-nanomolar cytotoxicity against the human squamous carcinoma derived A431 cells. In vivo imaging of Alexa Fluor 647-dye conjugates in A431-xenografted mice bearing subcutaneous tumors as the SCC model revealed unspecific binding of bivalent DARPins to the ubiquitously expressed EGFR. Tumor-targeting was verified 6 h post-injection solely for DD1 and scFvFc. The total of four administrations of 6.5 mg/kg DD1-MMAE or DFc-MMAE twice weekly did not cause any sequela in mice. MMAE conjugates showed no significant anti-tumor efficacy in vivo, but a trend towards increased necrotic areas (p = 0.2213) was observed for the DD1-MMAE (n = 5). 相似文献
69.
70.
Nils Hinrichsen 《Lipid Technology》2016,28(3-4):65-67
Since several years there has been a demand for food products free of palm oil, noticeable in the Western European market. Alternatives based on liquid oils, fully hydrogenated fats, and exotic fats like shea and sal etc., have been developed by the research groups of several specialty oils and fats suppliers. This article describes the advantages and disadvantages of those products and compares them to similar products based on palm oil. It is also discussed how reasonable the replacement of palm products would be, since sustainable and 3‐MCPD/glycidolester‐reduced palm based specialty oils are also available on the market. 相似文献