全文获取类型
收费全文 | 3462篇 |
免费 | 184篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 61篇 |
化学工业 | 836篇 |
金属工艺 | 53篇 |
机械仪表 | 35篇 |
建筑科学 | 95篇 |
矿业工程 | 3篇 |
能源动力 | 76篇 |
轻工业 | 407篇 |
水利工程 | 38篇 |
石油天然气 | 19篇 |
无线电 | 341篇 |
一般工业技术 | 557篇 |
冶金工业 | 740篇 |
原子能技术 | 22篇 |
自动化技术 | 367篇 |
出版年
2024年 | 8篇 |
2023年 | 37篇 |
2022年 | 104篇 |
2021年 | 141篇 |
2020年 | 73篇 |
2019年 | 77篇 |
2018年 | 91篇 |
2017年 | 115篇 |
2016年 | 113篇 |
2015年 | 94篇 |
2014年 | 144篇 |
2013年 | 164篇 |
2012年 | 164篇 |
2011年 | 269篇 |
2010年 | 168篇 |
2009年 | 175篇 |
2008年 | 176篇 |
2007年 | 179篇 |
2006年 | 128篇 |
2005年 | 102篇 |
2004年 | 86篇 |
2003年 | 76篇 |
2002年 | 82篇 |
2001年 | 54篇 |
2000年 | 40篇 |
1999年 | 48篇 |
1998年 | 148篇 |
1997年 | 83篇 |
1996年 | 71篇 |
1995年 | 63篇 |
1994年 | 43篇 |
1993年 | 46篇 |
1992年 | 24篇 |
1991年 | 23篇 |
1990年 | 26篇 |
1989年 | 20篇 |
1988年 | 18篇 |
1987年 | 21篇 |
1986年 | 22篇 |
1985年 | 16篇 |
1984年 | 15篇 |
1983年 | 13篇 |
1982年 | 6篇 |
1981年 | 13篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1977年 | 5篇 |
1976年 | 18篇 |
1973年 | 5篇 |
1970年 | 7篇 |
排序方式: 共有3650条查询结果,搜索用时 15 毫秒
11.
T Rodriguez E Baumgarten R Fengler D Soumpasis G Henze 《Canadian Metallurgical Quarterly》1995,207(4):207-210
Nine children of the ALL-REZ BFM 87 and 90 trial received L-Asparginase (L-ASP) as a continuous infusion for 48-72 hs (i.e. 25 therapy cycles). Seven patients had had an allergic reaction towards an i.m. application (i.m., 29 therapy cycles). Two further patients got L-ASP initially as continuous infusion. The i.m. applications were carried out 19 times with Erwinia and 10 times with E. coli-Asparaginase, the continuous infusions 15 times with Erwinia and 10 times with E. coli-Asparaginase. In case of four patients continuous infusions of the same L-ASP type (E. coli or Erwinia) was well tolerated, after there had been an allergic reaction after i.m. application. Allergic reactions after i.m. application occurred during 10 courses as local painful erythema, during five courses as urticaria, during four courses as a general exanthema during one course as difficult breathing and during a further course as drop in blood pressure. After continuous infusion of L-ASP urticaria and difficult breathing occurred once and a transient exanthema two times. There was no anaphylactic reaction in any case. These data show that i.m. application of L-ASP causes no life-threatening side effects but allergic reactions (local pain and swelling) which clearly impaired general condition. Continuous infusion is a pharmacologically equivalent alternative with less impairment of the patients' general condition. 相似文献
12.
The T-maze test has been used to study several entirely different issues: spontaneous alternation behavior (SAB), perseveration behavior (PB), and behavioral lateralization. Despite the fact that in this test the behavior studied is always the same one (i.e., side choice), the possible relationships among SAB, PB, and lateralization have not been previously evaluated. The present study investigated the relationships among these functions. The results demonstrated that (1) shock increases PB and lateralization decreases SAB, (2) practice increases lateralization and decreases SAB but does not modify PB, and (3) there are sex differences for alternation and SAB. Because these functions are expressed by the same behavioral pattern, they must be quantified simultaneously to avoid mistaken conclusions when the T-maze test is used. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
13.
14.
Carl Bruch Stephanie Altman Mishkat Al-Moumin Jessica Troell Elana Roffman 《国际水资源开发杂志》2007,23(4):595-624
For millennia, countries in the Middle East and North Africa (MENA) region have developed laws, regulations and other rules to govern their scarce water. These laws have been updated in recent years. This review of the legal frameworks (including regulations, decrees and other rules) reveals both progress and gaps in managing water quality, water quantity and procedural aspects. Of note, while the general frameworks are usually in place, in many instances the necessary details are lacking to give effect to the goals. However, in some instances the legal frameworks governing water lack certain key principles or approaches. In order to effectively meet the growing demands on their water resources, MENA countries will need to further strengthen and develop their legal frameworks. 相似文献
15.
Oxidation and mineralisation of substituted phenols by Fenton's reagent and catalytic wet oxidation.
Catalytic abatement of solutions of 1,000 mg/L in phenol, ortho and para nitrophenol and ortho and para cresols was acomplished by using two catalytic systems. Fenton's reagent was used at 50 degrees C by adding 10 mg/L of ferrous cation and different dosages of H2O2. The mixture was reacting isothermically in a batch way during 3 hours. Catalytic wet oxidation (CWO) was carried out by using a commercial Activated Carbon, Industrial React FE01606A, CWO runs were carried out in a fixed bed reactor (FBR) with concurrent upflow. Temperature and oxygen pressure of the reactor were set to 160 degrees C and 16 bar, respectively. While phenols are quicky oxidised by the Fenton reagent higher mineralisation was obtained in the CWO process. 相似文献
16.
17.
18.
Snell-Johns Jessica; Mendez Julia L.; Smith Bradley H. 《Canadian Metallurgical Quarterly》2004,18(1):19
Various definitions exist for what constitutes family therapy. In this article, we consider family therapy to encompass any intervention that targets family interactions and conceptualizes problems as existing beyond individual clients. Numerous individual studies and several quantitative reviews have established family therapy as an effective treatment modality and the treatment of choice for many disorders. However, critiques of existing service provision highlight the unfortunate fact that numerous barriers to treatment exist at multiple levels of the broader ecology, preventing many families from benefiting from these services. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
19.
H. Fan A. Wright J. Gabaldon A. Rodriguez C.J. Brinker Y.‐B. Jiang 《Advanced functional materials》2006,16(7)
The synthesis of three‐dimensionally ordered, transparent gold‐nanocrystal (NC)/silica superlattice thin films using the self‐assembly (by spin‐coating) of water‐soluble gold nanocrystal micelles and soluble silica is reported by Fan and co‐workers on p. 891. The robust, 3D NC/silica superlattice films are of interest for the development of collective optical and electronic phenomena, and, importantly, for the integration of NC arrays into device architectures. Nanocrystals and their ordered arrays hold many important applications in fields such as catalysis, surface‐enhanced Raman spectroscopy based sensors, memory storage, and electronic and optical nanodevices. Herein, a simple and general method to synthesize ordered, three‐dimensional, transparent gold nanocrystal/silica superlattice thin films by self‐assembly of gold nanocrystal micelles with silica or organosilsesquioxane by spin‐coating is reported. The self‐assembly process is conducted under acidic sol–gel conditions (ca. pH 2), ensuring spin‐solution homogeneity and stability and facilitating the formation of ordered and transparent gold nanocrystal/silica films. The monodisperse nanocrystals are organized within inorganic host matrices as a face‐centered cubic mesostructure, and characterized by transmission electron spectroscopy and X‐ray diffraction. 相似文献
20.
Placid Rodriguez 《Metallurgical and Materials Transactions A》2004,35(9):2697-2705
A critical review of available results on the dependence of grain size on the activation parameters for deformation, specifically,
the activation volume, V*, and the thermal component of flow stress, σ*, has been carried out with a view to verifying the Armstrong prediction that identifies the Hall-Petch (H-P) intercept with
the easy slip system and the H-P slope with the most difficult system in polycrystals. The influence of slip system choice
is demonstrated using results on Cd and Zr. The Armstrong prediction is valid for basal slip hcp metals, such as Cd and Zn,
with V* and σ* determined by the difficult pyramidal slip. For the prism slip metals such as Zr and Ti, V* and σ* are controlled by interstitial solutes and are independent of grain size. The results on Zr are used to highlight the influence
of dynamic strain aging on the H-P parameters. In bcc metals, in which the Peierls-Nabarro barrier is the rate-controlling
obstacle, V* and σ* are again independent of grain size. For fcc metals, correlation of the H-P slope with the cross-slip stress, predicted
by the Armstrong model, has been demonstrated for a few cases. The variation of V* with grain size in Ni as reported by Narutani and Takamura (Acta Metall. Mater., 1991, vol. 227, pp. 2037–49) is newly interpreted in terms of the Armstrong model that associates the H-P intercept in fcc
metals with dislocation intersections and the H-P slope with cross-slip, and provides realistic results for the activation
volumes for the two processes.
This article is based on a presentation given in the symposium “Dynamic Deformation: Constitutive Modeling, Grain Size, and
Other Effects: In Honor of Prof. Ronald W. Armstrong,” March 2–6, 2003, at the 2003 TMS/ASM Annual Meeting, San Diego, California,
under the auspices of the TMS/ASM Joint Mechanical Behavior of Materials Committee. 相似文献