全文获取类型
收费全文 | 4158篇 |
免费 | 110篇 |
国内免费 | 17篇 |
专业分类
化学 | 2908篇 |
晶体学 | 40篇 |
力学 | 103篇 |
数学 | 192篇 |
物理学 | 1042篇 |
出版年
2021年 | 42篇 |
2020年 | 38篇 |
2019年 | 44篇 |
2018年 | 32篇 |
2017年 | 31篇 |
2016年 | 74篇 |
2015年 | 72篇 |
2014年 | 86篇 |
2013年 | 193篇 |
2012年 | 212篇 |
2011年 | 251篇 |
2010年 | 124篇 |
2009年 | 113篇 |
2008年 | 206篇 |
2007年 | 199篇 |
2006年 | 215篇 |
2005年 | 189篇 |
2004年 | 199篇 |
2003年 | 176篇 |
2002年 | 188篇 |
2001年 | 133篇 |
2000年 | 111篇 |
1999年 | 72篇 |
1998年 | 55篇 |
1997年 | 56篇 |
1996年 | 54篇 |
1995年 | 39篇 |
1994年 | 49篇 |
1993年 | 51篇 |
1992年 | 62篇 |
1991年 | 37篇 |
1990年 | 40篇 |
1989年 | 46篇 |
1988年 | 41篇 |
1987年 | 42篇 |
1986年 | 37篇 |
1985年 | 82篇 |
1984年 | 77篇 |
1983年 | 25篇 |
1982年 | 39篇 |
1981年 | 32篇 |
1980年 | 38篇 |
1979年 | 64篇 |
1978年 | 46篇 |
1977年 | 53篇 |
1976年 | 47篇 |
1975年 | 31篇 |
1974年 | 24篇 |
1973年 | 18篇 |
1972年 | 15篇 |
排序方式: 共有4285条查询结果,搜索用时 328 毫秒
41.
T. Kimura H. Gotoh Y. Kobayashi J. Akatsu 《Journal of Radioanalytical and Nuclear Chemistry》1988,125(1):29-40
A non-destructive method for determining the amount of actinoids has been developed. The method is based on thermal neutron coincidence counting and employs a selective detection of neutrons resulting from the spontaneous fission of actinoids. The detection system is described in detail and the measurement results of244Cm as an example are presented. The results show that the measured fission rate of244Cm is consistent with the fission rate calculated from ENDF/B-V data and that the amount of244Cm can be determined within about 5% accuracy even in the presence of a large amount of actinoids, for example, up to 2.6·106, 3.6·104, or 1.6·103 times in the mass ratio of239Pu,241Am, or240Pu to244Cm, respectively. 相似文献
42.
An evaluation of LH- and FSH-RIA BEAD kits based on IRMA was carried out. The results obtained with the methods characterized by the use of monoclonal antibodies, i.e., one is linked to solid phase, and another is isotopically labeled, were compared with those determined by the Daiichi LH- and FSH-kits. Intra- and inter-assay precision, recovery, linearity, and specificity of both methods were favorable without exceptions. The cross reactivity of the LH kit to 5,000 mIU/ml hCG revealed within the range of less than 3 mIU/ml. Significant correlations were observed between the results derived from conventional Daiichi LH- and FSH-kits. The results from the conventional kits exhibited 30 to 40% of those from the Daiichi kits, considered to be mainly due to the difference in standard calibrations used. Among the individuals within the normal menstrual cycle, the serum LH- and FSH-levels determined by the present kits gave a typical pattern with a peak in the preovulatory phase. On the other hand, the LH- and FSH-values of individuals in normal pregnancy revealed strikingly decreased in comparison with those of non-pregnant women. 相似文献
43.
44.
45.
46.
M Sugiyama T Sakamoto K Tabata K Endo K Ito M Kobayashi H Fukumi 《Chemical & pharmaceutical bulletin》1989,37(8):2122-2131
Thiazolo[3,2-a]thieno[3,2-d]-, [3,4-d]- and [2,3-d]pyrimidin-5-one derivatives (6, 11 and 16), and polymethylene condensed thieno[3,2-d]-, [3,4-d]- and [2,3-d]pyrimidin-5-one derivatives (19-21), in which the oxygen atom of the oxazolidine moiety in 3 was replaced by a sulfur atom or methylene groups, were synthesized and evaluated for gastric antisecretory activity in pylorus-ligated rats. The structure-activity relationships of these compounds are discussed. 相似文献
47.
48.
49.
M. Takagaki K. Ono S-I. Masunaga Y. Kinashi Y. Sakurai T. Kobayashi S-I. Miyatake N. Hashimoto 《Journal of Radioanalytical and Nuclear Chemistry》2001,247(2):389-392
Quantitative determination of ppb-order 10B was carried out in a small number of cultured tumor cells by particle tracks by the 10B(n,)7Li reactions using solid state nuclear track detector (SSNTD) for boron neutron capture therapy research. The detection limit of 10B concentration in tumor cells is less than 1·10-3 ppm under our experimental conditions which permits the quantitative determination of 10B in a small number of boronated tumor cells (105/ml = ca. 0.1 mg). Boron quantities in tumor cells determined were well compatible with the tumor cell killing effects of boron neutron capture therapy. 相似文献
50.
Relative concentrations of nine isomers of Ca at C82 derived from the C82 isolated-pentagon-rule satisfying cages are computed in a wide temperature interval. The computations are based on the Gibbs energy constructed from partition functions supplied with molecular parameters from density functional theory calculations. Five structures show significant populations at higher temperatures: C2v > Cs > C2 > C3v > Cs. The computed relative stabilities agree well with available observations. 相似文献