全文获取类型
收费全文 | 2284篇 |
免费 | 46篇 |
国内免费 | 7篇 |
专业分类
化学 | 1453篇 |
晶体学 | 55篇 |
力学 | 28篇 |
数学 | 266篇 |
物理学 | 535篇 |
出版年
2017年 | 20篇 |
2016年 | 32篇 |
2015年 | 20篇 |
2014年 | 33篇 |
2013年 | 74篇 |
2012年 | 66篇 |
2011年 | 75篇 |
2010年 | 50篇 |
2009年 | 47篇 |
2008年 | 83篇 |
2007年 | 67篇 |
2006年 | 83篇 |
2005年 | 56篇 |
2004年 | 47篇 |
2003年 | 45篇 |
2002年 | 54篇 |
2001年 | 38篇 |
2000年 | 43篇 |
1999年 | 39篇 |
1998年 | 39篇 |
1997年 | 39篇 |
1996年 | 35篇 |
1995年 | 54篇 |
1994年 | 38篇 |
1993年 | 33篇 |
1992年 | 28篇 |
1991年 | 35篇 |
1990年 | 29篇 |
1989年 | 32篇 |
1988年 | 43篇 |
1987年 | 35篇 |
1986年 | 37篇 |
1985年 | 36篇 |
1984年 | 44篇 |
1983年 | 27篇 |
1982年 | 21篇 |
1981年 | 49篇 |
1980年 | 41篇 |
1979年 | 29篇 |
1978年 | 38篇 |
1977年 | 29篇 |
1976年 | 39篇 |
1975年 | 27篇 |
1974年 | 37篇 |
1973年 | 33篇 |
1972年 | 18篇 |
1971年 | 17篇 |
1970年 | 23篇 |
1967年 | 22篇 |
1965年 | 17篇 |
排序方式: 共有2337条查询结果,搜索用时 15 毫秒
131.
Immunoassay methods for paralytic shellfish poisoning toxins 总被引:1,自引:0,他引:1
Usleber E Dietrich R Bürk C Schneider E Märtlbauer E 《Journal of AOAC International》2001,84(5):1649-1656
The current status of immunochemical techniques for analysis of paralytic shellfish poisoning (PSP) toxins is summarized. Important aspects regarding production of the biological reagents necessary for immunochemical methods, the characteristics of polyclonal and monoclonal antibodies against saxitoxin and neosaxitoxin, and the importance of test sensitivity and specificity are discussed. Applications of immunochemical techniques for PSP toxins include microtiter plate enzyme immunoasays and enzyme-linked immunofiltration assays for toxin detection, and immunoaffinity chromatography (IAC) for sample extract cleanup. A major advantage of enzyme immunoassay (EIA) is simplicity and rapidity of the test procedure, and higher sensitivity than other methods. However, quantitative agreement between EIA and mouse bioassay is dependent on antibody specificity and the toxin profile in the shellfish; thus, both over- and underestimation of total toxicity may occur. For screening purposes, however, EIAs offer major advantages over the mouse bioassay, which is criticized in Europe because of animal welfare. A major application of antibodies against PSP toxins is their use for extract cleanup by IAC, which gives highly purified extracts, thereby enhancing determination of PSP toxins by conventional physicochemical methods such as liquid chromatography. IAC can also be used to isolate PSP toxins for preparation of analytical standard solutions. 相似文献
132.
Molybdenum single crystals predeformed at low temperature (T1 ≦ 293 K) exhibit during tensile reloading at T2 = 493 K pronounced work softening accompanied by stress serrations and localized slip. It is shown that the initial state for the development of coarse slip bands is the formation of narrow obstacle-free slip channels. The change from the homogeneous dislocation structure to the cell structure proceeds in a heterogeneous and discontinuous manner. 相似文献
133.
The UHV surface preparation of AB materials (crystals and thin films) has been monitored with XPS and AES. Clean and stoichiometric surfaces of AB crystals were prepared by means of low energy ion bombardment and subsequent low temperature annealing. Stoichiometric Cd3As2 and Zn3P2 thin films with very low amounts of C and O were deposited by the evaporation of bulk material in the UHV. The quality of prepared AB crystal and thin film surfaces was sufficient to carry out density of states investigations (UPS, RELS) with success. 相似文献
134.
Dietrich Braun 《Macromolecular Symposia》1986,4(1):41-42
Methyl methacrylate, benzyl methacrylate, butyl methacrylate, and methacrylic acid can be polymerized by 1, 2, 2-tetraphenyl-1, 2-diphenoxyethane (TPPA), 1, 1, 2, 2-tetraphenyl-1, 2-bis-(trimethylsiloxy) ethane (TPSA), and 1, 1, 2, 2-tetraphenyl-1, 2-dicyanoethane (TPCA) (1–3). The polymerization with these initiators is characterized by three steps; in the first period oligomers from MMA and initiator radicals are formed by primary radical termination. 相似文献
135.
136.
137.
138.
139.
Various factors are discussed which might influence the equilibrium contact angle of nanodroplets placed on a solid substrate.
Special emphasis is put on the possible role of the dependence of the solid-liquid interface tension gSL \gamma^{{{\rm SL}}}_{} on the pressure in the liquid, which in nanodrops considerably exceeds the saturation pressure. We show that certain published
data regarding that dependence are meaningless because these have been deduced based on an inconsistent data analysis. 相似文献
140.
A number of recent papers have studied when symmetry causes frameworks on a graph to become infinitesimally flexible, or stressed,
and when it has no impact. A number of other recent papers have studied special classes of frameworks on generically rigid
graphs which are finite mechanisms. Here we introduce a new tool, the orbit matrix, which connects these two areas and provides
a matrix representation for fully symmetric infinitesimal flexes, and fully symmetric stresses of symmetric frameworks. The
orbit matrix is a true analog of the standard rigidity matrix for general frameworks, and its analysis gives important insights
into questions about the flexibility and rigidity of classes of symmetric frameworks, in all dimensions. 相似文献