全文获取类型
收费全文 | 6723篇 |
免费 | 223篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 63篇 |
综合类 | 1篇 |
化学工业 | 1090篇 |
金属工艺 | 89篇 |
机械仪表 | 101篇 |
建筑科学 | 267篇 |
矿业工程 | 9篇 |
能源动力 | 152篇 |
轻工业 | 613篇 |
水利工程 | 44篇 |
石油天然气 | 8篇 |
无线电 | 494篇 |
一般工业技术 | 1009篇 |
冶金工业 | 2078篇 |
原子能技术 | 49篇 |
自动化技术 | 883篇 |
出版年
2022年 | 73篇 |
2021年 | 101篇 |
2020年 | 60篇 |
2019年 | 79篇 |
2018年 | 110篇 |
2017年 | 113篇 |
2016年 | 83篇 |
2015年 | 97篇 |
2014年 | 141篇 |
2013年 | 326篇 |
2012年 | 206篇 |
2011年 | 294篇 |
2010年 | 229篇 |
2009年 | 249篇 |
2008年 | 242篇 |
2007年 | 257篇 |
2006年 | 216篇 |
2005年 | 197篇 |
2004年 | 180篇 |
2003年 | 172篇 |
2002年 | 187篇 |
2001年 | 141篇 |
2000年 | 146篇 |
1999年 | 159篇 |
1998年 | 376篇 |
1997年 | 238篇 |
1996年 | 219篇 |
1995年 | 156篇 |
1994年 | 146篇 |
1993年 | 138篇 |
1992年 | 98篇 |
1991年 | 67篇 |
1990年 | 80篇 |
1989年 | 94篇 |
1988年 | 83篇 |
1987年 | 83篇 |
1986年 | 62篇 |
1985年 | 65篇 |
1984年 | 90篇 |
1983年 | 76篇 |
1982年 | 70篇 |
1981年 | 68篇 |
1980年 | 66篇 |
1979年 | 68篇 |
1978年 | 50篇 |
1977年 | 63篇 |
1976年 | 102篇 |
1975年 | 50篇 |
1974年 | 41篇 |
1972年 | 29篇 |
排序方式: 共有6950条查询结果,搜索用时 203 毫秒
101.
There exists a movement within the field of psychology to incorporate religious material into the overall conceptualization and treatment of the client. This article questions the appropriateness of such incorporation and emphasizes instead the distinction the therapist needs to make between religious and psychological material in the psychotherapeutic setting. The therapist must also be aware of how religious material can intensify the transference, resistance, and countertransference, thereby complicating the therapeutic process. Client issues that relate to the religious identity of the therapist or invoke a sense of exclusive similarity in the therapeutic dyad can further complicate the therapy. Such complications suggest that the avoidance of both overt and covert messages that communicate the therapist's personal values and beliefs may be beneficial for therapy. Case examples with 4 clients (aged 18–56 yrs) are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
102.
103.
During studies to develop serum tests of small intestinal permeability, we detected an unidentified disaccharide in HPLC traces of sera from untreated celiacs. This present study aimed to identify the disaccharide and determine whether the presence of the disaccharide in the serum after an oral challenge had potential as a simple screening test for celiac disease. The disaccharide was identified as sucrose by incubation studies of sera with disaccharidases. Twenty untreated celiacs, 15 treated celiacs, and 20 normal or dyspeptic controls were studied for the presence of sucrose in their serum after an oral load (8 g). The results in celiacs were compared with the presence of serum IgA endomysial antibodies. The 10 normal controls were also given a larger sucrose challenge (50 g). Ten of the untreated celiacs and 10 controls had their brush border disaccharidase activities measured. Sucrose eluted in the same position as the unidentified disaccharide in the HPLC trace and the latter could be removed by incubation with sucrase. All untreated celiacs but none of the treated celiacs had sucrose in their serum after the 8-g oral challenge. None of the controls had sucrose in their serum after the 8-g or 50-g challenges. Three untreated celiacs were IgA endomysial antibody negative as were all the treated cases. Brush border sucrase activity was low in untreated celiac disease. The presence of sucrose in the serum after an oral load shows promise as a noninvasive test for celiac disease. 相似文献
104.
AR Barker FN Schrick MJ Lewis HH Dowlen SP Oliver 《Canadian Metallurgical Quarterly》1998,81(5):1285-1290
In the common goby, Pomatoschistus microps (Pisces, Gobiidae), males build nests under mussel shells where they care for the eggs until hatching. To investigate why male common gobies cannibalize their own eggs (filial cannibalism), we conducted a feeding experiment. Males given little food ate from their eggs more often than males given food in excess. However, males given mussel meat in excess did not eat more of their eggs than males fed with both mussel meat in excess and goby eggs. This may suggest that male common gobies cannibalize their eggs to obtain energy rather than essential nutrients lacking in other diets. Moreover, males ate their whole clutch if it was exceptionally small regardless of food treatment, suggesting that males stop investing in their clutch if its reproductive value is less than the cost of guarding it. Thus, whole clutch cannibalism and partial clutch cannibalism seem to be governed by different factors. Furthermore, poorly built nests were associated with starved males, suggesting that nest concealing is costly. There was an association between how well the nest was built and partial clutch filial cannibalism, suggesting that the appearance of the nest may indicate the condition of the male, and thus the risk of filial cannibalism. Copyright 1998 The Association for the Study of Animal Behaviour. 相似文献
105.
MJ O'Neill JA Lewis HM Noble S Holland C Mansat JE Farthing G Foster D Noble SJ Lane PJ Sidebottom SM Lynn MV Hayes CJ Dix 《Canadian Metallurgical Quarterly》1998,61(11):1328-1331
Methanolic extracts prepared from the leaves of Lantana camara have been found to inhibit human thrombin. An assay, in which thrombin activity is measured as a function of clot formation from fibrinogen, was used to guide the fractionation and purification of five principal active constituents (1-5), which were all characterized as 5,5-trans-fused cyclic lactone-containing euphane triterpenes. 相似文献
106.
CE Lewis V George M Fouad V Porter D Bowen N Urban 《Canadian Metallurgical Quarterly》1998,19(5):461-476
The Women's Health Trial:Feasibility Study in Minority Populations (WHT:FSMP) examined the feasibility of recruiting postmenopausal women from a broad range of racial and socioeconomic backgrounds into a primary prevention trial requiring marked reductions in dietary fat. Postmenopausal women aged 50-79 yr who had no history of cardiovascular disease or cancer and who consumed 36% or more total energy from fat qualified to participate. We randomized the women into dietary intervention (60%) or control (40%) groups; we aimed to randomize 750 women in 18 months in each of the three clinical centers. All centers achieved goals for randomization based on ethnicity, and two centers exceeded overall recruitment goals. The greatest source of randomized participants was mass mailing, followed by items in the media, referrals, and community outreach. Recruitment yields were generally similar for the ethnic groups but lower for less-educated participants. The experience of WHT:FSMP indicates that postmenopausal women from the African-American, Hispanic, and non-Hispanic white communities can be recruited into dietary intervention studies for the prevention of disease. 相似文献
107.
Lyndsay A. Cartwright Sue Hayes Douglas C. Tozer Dan Clayton Mary-Ann Burns Dena Lewis Noah Gaetz Namrata Shrestha 《Journal of Great Lakes research》2021,47(2):273-282
Beneficial use impairments (BUIs) under the Great Lakes Water Quality Agreement identify environmental issues requiring remedial action within the Great Lakes Areas of Concern (AOCs). We conducted this study to support the assessment of the wildlife component of BUI 3: degradation of fish and wildlife populations. We compared bird and amphibian (frogs and toads) data from the Toronto and Region Conservation Authority’s Terrestrial Long-term Monitoring Program in the Toronto and Region AOC to an adjacent, but otherwise similar, reference watershed, Duffins Creek. Twelve of 13 targets were met within the AOC for forest bird, wetland bird, meadow bird and amphibian populations based on averages of mean annual values at sites within the AOC that were within two standard deviations of averages at sites in the Duffins Creek reference watershed between 2008 and 2017. Even though wildlife populations within the AOC were within the normal range of variability expected from a reference watershed, they were often at lower levels than within the Duffins Creek reference watershed. In addition, forest bird and amphibian populations were negatively affected by urbanization within the AOC and meadow bird indices declined. We conclude that while wildlife populations within the AOC currently meet targets for BUI 3, they continue to be negatively impacted by numerous stressors that are primarily related to past and ongoing urbanization. Thus, continued restoration of wildlife habitat and protection of existing habitat within the AOC is highly recommended. 相似文献
108.
Ma Shizhou Beazley Karen F. Nussey Patrick Greene Christopher S. 《Water Resources Management》2021,35(14):4825-4840
Water Resources Management - The Active River Area (ARA) is a spatial approach for identifying the extent of functional riparian area. Given known limitations in terms of input elevation data... 相似文献
109.
Ghukasyan Tsolak Yeshilbashyan Yeva Avetisyan Karen 《Programming and Computer Software》2021,47(1):56-66
Programming and Computer Software - In this work, we present purely subword-based alternatives to fastText word embedding algorithm The alternatives are modifications of the original fastText... 相似文献
110.
Messing Karen Lefrançois Mélanie Saint-Charles Johanne 《Computer Supported Cooperative Work (CSCW)》2021,30(2):215-249
Computer Supported Cooperative Work (CSCW) - Work activity ergonomics (sometimes called francophone ergonomics) draws heavily on observation in order to support transformation of work to arrive at... 相似文献