全文获取类型
收费全文 | 7559篇 |
免费 | 378篇 |
国内免费 | 25篇 |
学科分类
工业技术 | 7962篇 |
出版年
2023年 | 58篇 |
2022年 | 227篇 |
2021年 | 329篇 |
2020年 | 175篇 |
2019年 | 176篇 |
2018年 | 245篇 |
2017年 | 247篇 |
2016年 | 288篇 |
2015年 | 211篇 |
2014年 | 300篇 |
2013年 | 519篇 |
2012年 | 349篇 |
2011年 | 446篇 |
2010年 | 301篇 |
2009年 | 302篇 |
2008年 | 309篇 |
2007年 | 280篇 |
2006年 | 191篇 |
2005年 | 166篇 |
2004年 | 163篇 |
2003年 | 137篇 |
2002年 | 138篇 |
2001年 | 83篇 |
2000年 | 65篇 |
1999年 | 67篇 |
1998年 | 251篇 |
1997年 | 270篇 |
1996年 | 193篇 |
1995年 | 143篇 |
1994年 | 91篇 |
1993年 | 98篇 |
1992年 | 37篇 |
1991年 | 34篇 |
1990年 | 29篇 |
1989年 | 36篇 |
1988年 | 43篇 |
1987年 | 35篇 |
1986年 | 26篇 |
1985年 | 40篇 |
1984年 | 47篇 |
1983年 | 45篇 |
1982年 | 56篇 |
1981年 | 66篇 |
1980年 | 70篇 |
1979年 | 39篇 |
1978年 | 47篇 |
1977年 | 130篇 |
1976年 | 241篇 |
1975年 | 22篇 |
1973年 | 22篇 |
排序方式: 共有7962条查询结果,搜索用时 0 毫秒
51.
Emilia Piosik Marta Ziegler-Borowska Dorota Cheminiak-Dudkiewicz Tomasz Martyski 《International journal of molecular sciences》2021,22(5)
An adsorption process of magnetite nanoparticles functionalized with aminated chitosan (Fe3O4-AChit) showing application potential in nanomedicine into cell membrane models was studied. The cell membrane models were formed using a Langmuir technique from three selected phospholipids with different polar head-groups as well as length and carbon saturation of alkyl chains. The research presented in this work reveals the existence of membrane model composition-dependent regulation of phospholipid-nanoparticle interactions. The influence of the positively charged Fe3O4-AChit nanoparticles on a Langmuir film stability, phase state, and textures is much greater in the case of these formed by negatively charged 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DPPG) than those created by zwitterionic 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC). The adsorption kinetics recorded during penetration experiments show that this effect is caused by the strongest adsorption of the investigated nanoparticles into the DPPG monolayer driven very likely by the electrostatic attraction. The differences in the adsorption strength of the Fe3O4-AChit nanoparticles into the Langmuir films formed by the phosphatidylcholines were also observed. The nanoparticles adsorbed more easily into more loosely packed POPC monolayer. 相似文献
52.
S. Kapi
ski 《Journal of Materials Processing Technology》1996,60(1-4):197-200
The paper presents the concepts of solving of deep drawing process for bimetal elements of sheet materials. The inertia forces, plastic hardening behaviour of the deformed material and dynamic stress are utilized in the problems of plasticity. The experimental results and general conclusion are presented at the end of the paper. 相似文献
53.
54.
Dorota Butkiewicz Magorzata Krzeniak Agnieszka Gdowicz-Kosok Monika Giglok Magorzata Marszaek-Zeczak Rafa Suwiski 《International journal of molecular sciences》2021,22(11)
For non-small cell lung cancer (NSCLC), radiotherapy (RT) and platinum-based chemotherapy (CHT) are among the main treatment options. On the other hand, radioresistance and cytotoxic drug resistance are common causes of failure. The epidermal growth factor receptor (EGFR) plays an important role in radioresponse and therapy resistance. We hypothesized that single nucleotide polymorphisms (SNPs) in the EGFR gene might affect individual sensitivity to these treatments, and thus, therapy outcome and prognosis. The association between functional EGFR SNPs and overall (OS), locoregional recurrence-free (LFRS), and metastasis-free (MFS) survival was examined in 436 patients with unresectable NSCLC receiving RT and platinum-based CHTRT. In a multivariate analysis, the rs712830 CC homozygotes showed reduced OS in the whole group (p = 0.039) and in the curative treatment subset (p = 0.047). The rs712829 TT genotype was strongly associated with decreased LRFS (p = 0.006), and the T-C haplotype was a risk factor for locoregional recurrence in our patients (p = 0.003). The rs2227983 GG alone and in combination with rs712829 T was an indicator of unfavorable LRFS (p = 0.028 and 0.002, respectively). Moreover, significant independent effects of these SNPs on OS, LRFS, and MFS were observed. Our results demonstrate that inherited EGFR gene variants may predict clinical outcomes in NSCLC treated with DNA damage-inducing therapy. 相似文献
55.
A series of binary blends of poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and polytetrahydrofuran (PTHF), characterized by similar average molecular weights, with selected fatty acids (capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid) were prepared by melt mixing. Differential scanning calorimetry was applied to characterize the phase transitions of melting and crystallization, and a synergistic effect was found to occur for PEO/fatty acid blends, as evidenced by the values of the enthalpy of the phase transition. This effect was probably due to hydrogen bonding between PEO and the fatty (carboxylic) acids, which facilitated the formation of crystalline structures; an analysis of IR spectroscopy data showed a shift in the absorption bands of OH groups. The morphology development of the PEO/carboxylic acid blends, as observed with polarizing light microscopy, could be described as spherulitic growth with spontaneous selection of the lamellar thickness. The textures of the individual fibrils, consisting of stacks of several tens of lamellae corresponding to PPO and PTHF, were less regular than the texture of PEO and showed large macroscopic heterogeneity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 861–870, 2003 相似文献
56.
Qi Li Rongcai Xie Eric A. Mintz Jian Ku Shang 《Journal of the American Ceramic Society》2007,90(12):3863-3868
Palladium-modified nitrogen-doped titanium oxide (TiON/PdO) nanoparticles were synthesized by a sol–gel process, for visible-light-induced photocatalysis using humic acid (HA) as a target. Our work shows that palladium modification has strong effects on the optical and photocatalytic properties of nitrogen-doped titanium oxide (TiON) photocatalysts. TiON/PdO nanoparticles demonstrated an enhanced photocatalytic activity over TiON within a narrow range of palladium concentration. Beyond this range, the adverse effect of palladium modification was observed in the visible-light-induced degradation of HA. The effects of palladium modification are discussed in terms of its role in controlling electron–hole recombination. 相似文献
57.
Krzysztof Kaczmarski Dongmei Zhou Georges Guiochon 《Chemical engineering science》2003,58(11):2325-2338
The adsorption isotherm data of R- and S-1-indanol and of their racemic mixture on cellulose tribenzoate were measured by frontal analysis. These experimental data were fitted to the single-component and the modified competitive Bilangmuir isotherms. The overloaded elution profiles of bands of the pure enantiomers and of the racemic mixture were calculated for different sample sizes, using the best competitive isotherm model and the General Rate Model of chromatography coupled with the generalized Maxwell-Stefan equation that describes the surface diffusion flux. The calculated and the experimental profiles were found to be in excellent agreement in all cases. The parameters of the model of the mass transfer kinetics were derived from the band profiles obtained for the pure enantiomers. The same values of these parameters give an excellent prediction of the profiles of multicomponent bands. The new model described here allows a satisfactory interpretation of the competitive mass transfer kinetics. 相似文献
58.
高耐蚀性Zn—Co合金镀层钝化工艺的研究 总被引:1,自引:0,他引:1
研究了电镀Zn-Co合金镀层的钝化液的组成及工艺条件,溶液各成分及工艺条件对钝化膜质量的影响,通过几种腐蚀试验方法,测量了钝化膜的耐蚀性,结果表明,研究的钝化工艺可以得到耐蚀性良好的钝化膜。 相似文献
59.
60.
Topics in Catalysis - This Synthetic Gas Bench (SGB) study focuses on the effect of cell geometry and wall thickness on the gasoline NO x trap functionality. The data show that besides a NO x trap... 相似文献