全文获取类型
收费全文 | 490篇 |
免费 | 17篇 |
专业分类
电工技术 | 14篇 |
综合类 | 3篇 |
化学工业 | 93篇 |
金属工艺 | 17篇 |
机械仪表 | 1篇 |
建筑科学 | 27篇 |
能源动力 | 51篇 |
轻工业 | 31篇 |
水利工程 | 14篇 |
无线电 | 32篇 |
一般工业技术 | 59篇 |
冶金工业 | 113篇 |
原子能技术 | 6篇 |
自动化技术 | 46篇 |
出版年
2023年 | 3篇 |
2022年 | 13篇 |
2021年 | 13篇 |
2020年 | 9篇 |
2019年 | 12篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 13篇 |
2015年 | 5篇 |
2014年 | 11篇 |
2013年 | 18篇 |
2012年 | 14篇 |
2011年 | 32篇 |
2010年 | 12篇 |
2009年 | 19篇 |
2008年 | 28篇 |
2007年 | 31篇 |
2006年 | 24篇 |
2005年 | 25篇 |
2004年 | 21篇 |
2003年 | 15篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 12篇 |
1998年 | 30篇 |
1997年 | 21篇 |
1996年 | 12篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 2篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1986年 | 4篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1980年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有507条查询结果,搜索用时 10 毫秒
1.
2.
3.
The exfiltration of wastewater from sewer systems in urban areas causes a deterioration of soil and possibly groundwater quality. Beside the simulation of transport and degradation processes in the unsaturated zone and in the aquifer the analysis of the potential impact requires the estimation of quantity and temporal variation of wastewater exfiltration. Exfiltration can be assessed by the application of a leakage model. The hydrological approach was originally developed to simulate the interactions between the groundwater and surface water, it was adapted to allow for modelling of interactions between groundwater and sewer system. In order to approximate the exfiltration specific model parameters infiltration specific parameters were used as a basis. Scenario analysis of the exfiltration in the City of Dresden from 1997 to 1999 and during the flood event in August 2002 shows the variation and the extent of exfiltration rates. 相似文献
4.
Bushman Brad J.; Bonacci Angelicca M.; van Dijk Mirjam; Baumeister Roy F. 《Canadian Metallurgical Quarterly》2003,84(5):1027
Laboratory analog studies investigated the theory that narcissism and reactance contribute to causing rape. In Study 1, narcissism correlated positively with rape-supportive beliefs and negatively with empathy for rape victims. In Study 2, narcissists reported more enjoyment than other men of film depictions that presented consensual, affectionate activity followed by rape (but not in response to either affection or rape alone). In Study 3, narcissists were more punitive than other men toward a female confederate who refused to read a sexually arousing passage aloud to them. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
We evaluated the effect of repeated administration of OC125 F(ab')2 fragments on cancer antigen (CA) 125 determination in 210 serum samples from 30 patients. We found falsely high CA 125 concentrations in 142 (68%) samples, using a homologous CA 125 enzyme immunoassay (EIA) with OC125 antibodies. The Truquant OV2 method, which involves two other murine antibodies, and the IMx CA 125 method, which uses sheep antibodies as capture antibodies, resulted in only slightly increased (false-positive) values in some samples with exceptionally high CA 125 EIA values. We measured falsely low CA 125 values in 37 (18%) samples with the Truquant OV2 method. Interferences could be eliminated by removal of serum IgG. Our results suggest that interferences are to some extent caused by anti-idiotypic IgG induced by OC125 administration. Assays involving nonmurine anti-CA 125 antibodies as capture antibodies seem to be most suited for CA 125 determination after OC125 treatment, but in every case an apparent increase of CA 125 after OC125 infusion should be validated. 相似文献
6.
In this paper, the scattering of electromagnetic waves by a perfectly conducting semi-infinite elliptic cone is treated. The exact solution of this boundary value problem in problem-adapted spheroconal coordinates in the form of a spherical multipole expansion is of poor convergence if both the source point and the field point are far away from the cone's tip. Therefore, an appropriate sequence transformation of these series expansions (we apply the Shanks transformation) is necessary to numerically determine the dyadic diffraction coefficients and bistatic radar cross sections (RCS) for an arbitrary elliptic cone. Our far-field data for an elliptic cone, a circular cone, and a plane angular sector are compared with some other results obtained with the aid of quite different methods 相似文献
7.
8.
Summary
We report the synthesis of some new backbone fluorinated
polymers of the poly(phenylenevinylene) type. The new polymers
were characterised by NMR, SEC and X-ray powder diffraction. The
charge carrier mobilities were determined using pulse radiolysis
time resolved microwave conductivity (PR-TRMC) and the carrier
mobilities were compared to the similar non-fluorinated
analogues. The changes in charge carrier mobilities as a
function of molecular substitution pattern is discussed in terms
of other materials properties such as electronic structure and
absorption properties. The major result is that it was found
possible for this type of material to alter the electronic
energy levels by molecular substitution without imparting
significant changes in the magnitude of the charge carrier
mobilities and the optical properties. 相似文献
9.
Six misconceptions about evolutionary approaches to human behavior are exposed. Evidence is adduced to support the assertions that evolutionary approaches do not (a) adopt a reductionistic "gene-centered" level of analysis, (b) assume that natural selection is the only process that creates and designs ontogenetic processes and phenotypic outcomes, (c) assume that genes are the only agents responsible for the transgenerational inheritance of phenotypic traits and characteristics, (d) assume that genes are self-contained and impervious to extragenetic influences, (e) posit a strong form of genetic determinism, or (f) pay lip service to the role of the environment. Building straw men and knocking them down is an inherently destructive enterprise; integrating different approaches is a more constructive way of contributing to the growth of knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
This paper is the result of a plenary discussion session held at the 11th European Conference on Mixing. Three perspectives on mixing research are explored: that of the industrialist, the equipment manufacturer, and the academic researcher. There was strong agreement that, while the one dimensional problems are reasonably well understood and many engineers thus perceive that mixing is simple, current practice actually requires us to address complex, multi‐dimensional problems with interactions between mixing, reaction, multi‐phase physics, surface phenomena, and transport phenomena. Understanding these multi‐scale, multi‐mechanism problems requires models which include interactions between the phenomena, and allow the effects of these interactions to emerge. Developing these models will require us to shift our perspective on mixing from one of equipment design to one of the mixing field as a fundamental physical mechanism. 相似文献