全文获取类型
收费全文 | 4850篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
综合类 | 1篇 |
化学工业 | 38篇 |
金属工艺 | 2篇 |
机械仪表 | 1篇 |
建筑科学 | 1篇 |
矿业工程 | 16篇 |
能源动力 | 5篇 |
轻工业 | 30篇 |
水利工程 | 2篇 |
无线电 | 5篇 |
一般工业技术 | 20篇 |
冶金工业 | 4709篇 |
原子能技术 | 8篇 |
自动化技术 | 13篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 7篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 8篇 |
2016年 | 3篇 |
2014年 | 7篇 |
2013年 | 23篇 |
2012年 | 7篇 |
2011年 | 7篇 |
2010年 | 7篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2000年 | 2篇 |
1999年 | 150篇 |
1998年 | 1547篇 |
1997年 | 877篇 |
1996年 | 571篇 |
1995年 | 313篇 |
1994年 | 229篇 |
1993年 | 280篇 |
1992年 | 32篇 |
1991年 | 37篇 |
1990年 | 45篇 |
1989年 | 39篇 |
1988年 | 32篇 |
1987年 | 30篇 |
1986年 | 31篇 |
1985年 | 36篇 |
1983年 | 8篇 |
1982年 | 16篇 |
1981年 | 34篇 |
1980年 | 44篇 |
1979年 | 2篇 |
1978年 | 12篇 |
1977年 | 104篇 |
1976年 | 235篇 |
1975年 | 11篇 |
1973年 | 2篇 |
1970年 | 2篇 |
1963年 | 2篇 |
1955年 | 4篇 |
排序方式: 共有4851条查询结果,搜索用时 0 毫秒
21.
P Bermejo Benito MJ Abad Martínez AM Silván Sen A Sanz Gómez L Fernández Matellano S Sánchez Contreras AM Díaz Lanza 《Canadian Metallurgical Quarterly》1998,63(13):1147-1156
Buddlejasaponin I and saikosaponin 1 and 2, biologically active compounds from Scrophularia scorodonia and Bupleurum rigidum respectively, exert potent in vivo antiinflammatory effects on mouse ear edema induced by phorbol myristate acetate (PMA). The effects of these compounds on swelling and other inflammatory parameters are described. In screening for in vitro effects of saikosaponins on cellular systems generating cyclooxygenase (COX) and lipoxygenase (LOX) metabolites, we observed that most saikosaponins showed a significant effect. The action is more marked on LOX metabolite LTC4. Our data support the inhibition of arachidonic acid metabolism as one of the biochemical mechanisms that might be the rationale for the putative antiphlogistic activity of these saikosaponins. 相似文献
22.
To determine whether the presence of nonpathogenic piroplasms may confound field estimates of risk of Babesia microti infection, we identified sporozoites infecting the salivary glands of deer ticks (Ixodes dammini) by parallel microscopy and polymerase chain reaction assays. Piroplasms were evident in 14.4% of adult ticks from sites in the northcentral and northeastern United States. Of these, 83.3% contained DNA characteristic of Ba. odocoilei. This cervid piroplasm was detected in all of the sites examined and generally was more prevalent than was Ba. microti. Because deer ticks transmit both Ba. odocoilei and Ba. microti, estimates of pathogen prevalence based solely on microscopy may overestimate the risk of human babesiosis. 相似文献
23.
Changes in proximate composition of anchovy were investigated during the catching season from October to March. In addition, stability of anchovy oil depending on storage temperature and time were studied. During the recent study, water, fat, protein and ash content of anchovy varied between 65.9–74.0%, 9.0–15.3%, 12.8–16.4% and 1.7–2.2%, respectively. The anchovy oil stored at 4C was found to be unacceptable for consumption at the end of the 90th day of storage according to peroxide, acid, unsaponifiable matter and thiobarbituric acid values. An identical sample stored at − 18C was acceptable for 120 days of storage, but eventually became unacceptable after that.
Anchovy has a great economic importance for the Turkish fishery industry. Approximately 42% of the annual catch of anchovy is used in fish meal and oil production in Turkey ( SIS 2002 ). Therefore, the proximate composition of anchovy and seasonal changes have fundamental importance for consumers, manufacturers and wholesalers, because it is important for consumers to know what they eat, for manufacturers to figure out how they manage long storage stability for their products, and for wholesalers to buy equivalent of their payment. An important issue that has attracted attention of the manufacturers is the storage life of fish oil. Therefore, the results presented in this study are expected to be useful for the fish oil industry in Turkey or even in other countries processing anchovy into fish oil. 相似文献
PRACTICAL APLICATIONS
Anchovy has a great economic importance for the Turkish fishery industry. Approximately 42% of the annual catch of anchovy is used in fish meal and oil production in Turkey ( SIS 2002 ). Therefore, the proximate composition of anchovy and seasonal changes have fundamental importance for consumers, manufacturers and wholesalers, because it is important for consumers to know what they eat, for manufacturers to figure out how they manage long storage stability for their products, and for wholesalers to buy equivalent of their payment. An important issue that has attracted attention of the manufacturers is the storage life of fish oil. Therefore, the results presented in this study are expected to be useful for the fish oil industry in Turkey or even in other countries processing anchovy into fish oil. 相似文献
24.
25.
26.
27.
28.
29.
The muscle bundles of the diaphragm form a curved sheet that extends from the chest wall to the central tendon. Each muscle bundle exerts a force in the direction of its curvature; the magnitude of this force is proportional to the curvature of the bundle. The contribution of this force to transdiaphragmatic pressure is maximal if the direction of bundle curvature is orthogonal to the surface and the curvature is maximal. That is, the contribution of muscle tension to transdiaphragmatic pressure is maximal if the muscle bundles lie along lines that are both geodesics and lines of maximal principal curvature of the surface. A theory of diaphragm shape is developed from the assumption that all muscle bundles have these optimal properties. The class of surfaces that are formed of line elements that are both geodescis and lines of principal curvature is described. This class is restricted. The lines that form the surface must lie in planes, and all lines must have the same shape. In addition, the orientation of the lines is restricted. An example of this class that is similar to the shape of the canine diaphragm is described, and the stress distribution in this example is analyzed. 相似文献
30.
Over the past decade the use of synthetic peptides corresponding to linear sequences of HLA molecules has progressed from a concept to a reality. These peptides are currently being evaluated in clinical trials. In animal models these peptides, given over 1 week with cyclosporin alone, induced long-term immunological tolerance (Figure 3). They may similarly induce tolerance in humans. The next major hurdle for such tolerogenic drugs, however, is to prove efficacy in clinical circumstances. Many of the drugs used to treat transplant patients today (steroids, cyclosporin, azathioprine, mycophenolate mofetil) may actually inhibit the 'active' processes of induction and maintenance of immunological tolerance. Demonstration that new drugs induce tolerance will require efficacy studies in other immune-mediated diseases in which monotherapy is feasible (such as psoriasis), before further advances can be made in the induction of transplant tolerance. In addition, rapid assays of rejection must be developed in order to reverse tolerance induction failures without graft damage or loss. Lastly, it will require heroic physicians, surgeons, and patients to make immunological tolerance a reproducible clinical reality. 相似文献