全文获取类型
收费全文 | 1826篇 |
免费 | 24篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 79篇 |
金属工艺 | 2篇 |
机械仪表 | 10篇 |
建筑科学 | 1篇 |
能源动力 | 5篇 |
轻工业 | 49篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 6篇 |
一般工业技术 | 9篇 |
冶金工业 | 1668篇 |
自动化技术 | 16篇 |
出版年
2022年 | 2篇 |
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 12篇 |
2018年 | 12篇 |
2017年 | 9篇 |
2016年 | 8篇 |
2015年 | 11篇 |
2014年 | 8篇 |
2013年 | 17篇 |
2012年 | 10篇 |
2011年 | 11篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 3篇 |
2007年 | 9篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 2篇 |
1999年 | 45篇 |
1998年 | 497篇 |
1997年 | 291篇 |
1996年 | 206篇 |
1995年 | 97篇 |
1994年 | 95篇 |
1993年 | 112篇 |
1992年 | 15篇 |
1991年 | 30篇 |
1990年 | 24篇 |
1989年 | 23篇 |
1988年 | 22篇 |
1987年 | 14篇 |
1986年 | 13篇 |
1985年 | 14篇 |
1983年 | 2篇 |
1982年 | 8篇 |
1981年 | 12篇 |
1980年 | 15篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 45篇 |
1976年 | 100篇 |
1975年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有1850条查询结果,搜索用时 46 毫秒
91.
92.
93.
Stahl's ear is a congenital malformation of the auricle, which is uncommon in non-Oriental societies. A number of different treatment modalities have been suggested, many of which yield unpredictable results. We review current treatment modalities from the English literature and describe a novel, simple surgical method of repair. First, a helical rim incision is made to expose the abnormal third crus and upper pole of the ear. The third crus is excised as a narrow wedge of cartilage and posterior skin, and the defect is closed primarily. The free third crus cartilage is then grafted onto the scaphal cartilage in an anatomically correct position to form a superior crus. The anterior skin flap is redraped and bolstered over this graft. Only a very small scar on the helical rim remains visible anteriorly. 相似文献
94.
Structural studies on an inhibitory antibody against Thermus aquaticus DNA polymerase suggest mode of inhibition 总被引:1,自引:0,他引:1
Murali R; Helmer-Citterich M; Sharkey DJ; Scalice ER; Daiss JL; Sullivan MA; Krishna Murthy HM 《Protein engineering, design & selection : PEDS》1998,11(2):79-86
TP7, an antibody against Thermus aquaticus DNA polymerase I (TaqP), is used
as a thermolabile switch in 'hot start' variations of PCR to minimize
non-specific amplification events. Earlier studies have established that
TP7 binds to the polymerase domain of TaqP, competes with primer template
complex for binding and is a potent inhibitor of the polymerase activity of
TaqP. We report crystallographic determination of the structure of an Fab
fragment of TP7 and computational docking of the structure with the known
three-dimensional structure of the enzyme. Our observations strongly
suggest that the origin of inhibitory ability of TP7 is its binding to
enzyme residues involved in DNA binding and polymerization mechanism.
Although criteria unbiased by extant biochemical data have been used in
identification of a putative solution, the resulting complex offers an
eminently plausible structural explanation of biochemical observations. The
results presented are of general significance for interpretation of docking
experiments and in design of small molecular inhibitors of TaqP, that are
not structurally similar to substrates, for use in PCR. Structural and
functional similarities noted among DNA polymerases, and the fact that
several DNA polymerases are pharmacological targets, make discovery of
non-substrate based inhibitors of additional importance.
相似文献
95.
Mohd Basyaruddin Abdul Rahman Noraini Abdul Ghani Nik Ghazali Nik Salleh Mahiran Basri Raja Noor Zaliha Abdul Rahman Abu Bakar Salleh 《Journal of Coatings Technology and Research》2011,8(2):229-236
Of late, UV-curable products are gaining attention in the wood industry because of the effectiveness and efficiency of this
method. UV-curable surface coatings are widely used because of their excellent properties and because they are environmentally
friendly products. In this study, immobilized Candida antarctica lipase B was used to catalyze formation of liquid wax esters, such as adipate esters, via a solvent-free process. The adipate
esters formed were then used as UV-curable reactants in the wood coating formulations, consisting of epoxy acrylate, additives,
and a photoinitiator. The performance of the products was evaluated by coating them onto glass tiles (using gel content, hardness,
and scratch resistance tests) and wood panels (using adhesion, impact, and heat resistance tests). The coated film from this
formulation performed well during the evaluation tests. The gel content exhibited more than 90% polymerization, while the
pendulum hardness gave a value of 55.25%. Both analyses were significant in determining the effect of irradiation cycles.
A scratch test was also carried out to verify the resistance of the coating. The maximum weight load which can be resisted
by the wax esters formulation is 4.5 N. 相似文献
96.
HM Cox 《Canadian Metallurgical Quarterly》1997,3(4):218-223
This paper describes one aspect of a study into the experiences in long-term healing of a community following the 1983 Ash Wednesday bushfire. Forty participants were interviewed, of whom 26 were residents and 14 disaster relief workers. The paper concentrates on the experiences of the latter, describing how they came to understand the bushfire affected the community and how they managed disaster work. For novices it was a profoundly difficult experience, for which they received little help and had to manage with whatever skill they drew on in their 'normal' working lives, mixed with a good deal of intuition. The paper suggests that health workers in vulnerable areas require preparation for a likely disaster; that 'outsiders' need to deal through existing community groups and individuals to gain access to those in need of their skills, and that they also require preparation for helping 'insiders' who are themselves victims of the catastrophe. 相似文献
97.
Pullulanase (EC.3.2.1.41) was used to generate more linear-chain dextrin from sago starch (24.9% amylose) such that the resulting product could act as a high amylose starch. A starch suspension of 5.0% (w/v) sago starch was heated at 100 °C for 45 min and, after cooling, the gelatinized sago starch was hydrolyzed with 2.0% (v/dry weight starch) pullulanase (Promozyme 400L, Novozymes A/S, Denmark) for 24 h. The linear long-chain dextrin (LLD) content of the hydrolysate after drying, was then compared with the initial LLD content. The surface morphology of the starch granules was observed with a scanning electron microscope (SEM). The effects of gelatinization, time of reaction, pretreatment with different strengths of hydrochloric acid prior to enzyme hydrolysis, and starch and enzyme concentrations were studied. Raw sago starch was resistant to the action of pullulanase, but caused an increase in the LLD of that sago starch from an initial concentration of 24.9–33.2% following gelatinization. The best conditions to maximize the amount of LLD were 5.0% (w/v) sago starch, 2.0% (v/w) enzyme and 12 h reaction time. Acid pretreatment of the sago starch did not cause greater improvement in the accessibility and susceptibility of pullulanase as the LLD content, following pullulanase action did not change significantly. Shrinkage on the surface of the starch granules was observed with the SEM. 相似文献
98.
HM Sansbury AE Wisehart-Johnson C Qi S Fulwood KE Meier 《Canadian Metallurgical Quarterly》1997,18(9):1817-1824
Phorbol ester-sensitive EL4 murine thymoma cells respond to phorbol 12-myristate 13-acetate with activation of ERK mitogen-activated protein kinases, synthesis of interleukin-2, and death, whereas phorbol ester-resistant variants of this cell line do not exhibit these responses. Additional aspects of the resistant phenotype were examined, using a newly-established resistant cell line. Phorbol ester induced morphological changes, ERK activation, calcium-dependent activation of the c-Jun N-terminal kinase (JNK), interleukin-2 synthesis, and growth inhibition in sensitive but not resistant cells. A series of protein kinase C activators caused membrane translocation of protein kinase C's (PKCs) alpha, eta, and theta in both cell lines. While PKC eta was expressed at higher levels in sensitive than in resistant cells, overexpression of PKC eta did not restore phorbol ester-induced ERK activation to resistant cells. In sensitive cells, PKC activators had similar effects on cell viability and ERK activation, but differed in their abilities to induce JNK activation and interleukin-2 synthesis. PD 098059, an inhibitor of the mitogen activated protein (MAP)/ERK kinase kinase MEK, partially inhibited ERK activation and completely blocked phorbol ester-induced cell death in sensitive cells. Thus MEK and/or ERK activation, but not JNK activation or interleukin-2 synthesis, appears to be required for phorbol ester-induced toxicity. Alterations in phorbol ester response pathways, rather than altered expression of PKC isoforms, appear to confer phorbol ester resistance to EL4 cells. 相似文献
99.
The muscle and brain creatine kinases of giant panda have been isolated and purified. The purified muscle and brain enzymes (MM and BB) are homogeneous on both the polyacrylamide gel electrophoresis in the presence and absence of SDS. Both enzymes are dimers, consisting of two identical subunits each with a molecular weight of 42,000 daltons. The characteristics of muscle and brain enzymes have been studied, respectively. The hybridized enzyme, MB, was prepared by hybridization of MM and BB. The kinetic parameters of MM, BB and MB were determined, respectively. The results from modification of SH groups show that the SH groups of panda creatine kinases are essential for their activity and among the all SH groups in the enzyme only one per subunit is essential for enzymatic activity. 相似文献
100.
J Alexander C Oseroff J Sidney P Wentworth E Keogh G Hermanson FV Chisari RT Kubo HM Grey A Sette 《Canadian Metallurgical Quarterly》1997,159(10):4753-4761
Transgenic mice expressing chimeric human (alpha1 and alpha2 HLA-A11 domains) and murine (alpha3, transmembrane, and cytoplasmic H-2Kb domains) class I molecules were derived. These mice were used as a model system to study the immunogenicity of human CTL epitopes and also to examine the aspects of Ag processing differences of mice vs man. Immunization of these mice with seven known HLA-A11-restricted CTL epitopes emulsified in IFA resulted in vigorous specific CTL responses. A larger panel of 45 A11-binding peptides was used to examine the relationship between immunogenicity in the HLA-A11/Kb transgenic mice and HLA-A11 binding capacity. Twenty-one of 28 (75%) peptides with high binding affinities (50% inhibitory concentration (IC50), 2-50 nM) and 7 of 13 (54%) intermediate binding peptides (IC50, 50-500 nM range) were immunogenic. In parallel, 19 of these peptides were used for in vitro primary immunizations of PBMC derived from HLA-A11 healthy human donors. It was found that 8 of 8 peptides that were able to elicit CTL in primary human in vitro cultures were also immunogenic in HLA-A11/Kb mice. Finally, HLA-A11/Kb transgenic mice were found to generate an A11/Kb restricted CTL response following immunization with influenza virus A/PR/8/34, suggesting that, at least to some extent, A11 epitopes are generated by transgenic mice as a result of natural in vivo processing and presentation. 相似文献