全文获取类型
收费全文 | 3554篇 |
免费 | 75篇 |
国内免费 | 10篇 |
专业分类
化学 | 2449篇 |
晶体学 | 44篇 |
力学 | 64篇 |
数学 | 168篇 |
物理学 | 914篇 |
出版年
2021年 | 23篇 |
2020年 | 47篇 |
2019年 | 47篇 |
2018年 | 40篇 |
2017年 | 24篇 |
2016年 | 49篇 |
2015年 | 53篇 |
2014年 | 69篇 |
2013年 | 153篇 |
2012年 | 140篇 |
2011年 | 177篇 |
2010年 | 119篇 |
2009年 | 112篇 |
2008年 | 180篇 |
2007年 | 204篇 |
2006年 | 187篇 |
2005年 | 137篇 |
2004年 | 123篇 |
2003年 | 133篇 |
2002年 | 131篇 |
2001年 | 109篇 |
2000年 | 126篇 |
1999年 | 77篇 |
1998年 | 51篇 |
1997年 | 49篇 |
1996年 | 41篇 |
1995年 | 41篇 |
1994年 | 42篇 |
1993年 | 55篇 |
1992年 | 47篇 |
1991年 | 47篇 |
1990年 | 36篇 |
1989年 | 49篇 |
1988年 | 49篇 |
1987年 | 42篇 |
1986年 | 35篇 |
1985年 | 49篇 |
1984年 | 51篇 |
1983年 | 47篇 |
1982年 | 43篇 |
1981年 | 29篇 |
1980年 | 32篇 |
1979年 | 48篇 |
1978年 | 43篇 |
1977年 | 47篇 |
1976年 | 16篇 |
1975年 | 26篇 |
1974年 | 30篇 |
1973年 | 15篇 |
1967年 | 16篇 |
排序方式: 共有3639条查询结果,搜索用时 47 毫秒
31.
Watanabe G Umetsu K Yuasa I Sato M Sakabe M Naito E Yamanouchi H Suzuki T 《Electrophoresis》2001,22(3):418-420
We present a simple and rapid polymerase chain reaction (PCR)-based technique, termed consumed allele-specific primer analysis (CASPA), as a new strategy for single nucleotide polymorphism (SNP) analysis. The method involves the use of labeled allele-specific primers, differing in length, with several noncomplementary nucleotides added in the 5'-terminal region. After PCR amplification, the amounts of the remaining primers not incorporated into the PCR products are determined. Thus, nucleotide substitutions are identified by measuring the consumption of primers. In this study, the CASPA method was successfully applied to ABO genotyping. In the present method, the allele-specific primer only anneals with the target polymorphic site on the DNA, so it is not necessary to analyze the PCR products. Therefore, this method is only little affected by modification of the PCR products. The CASPA method is expected to be a useful tool for typing of SNPs. 相似文献
32.
To sophisticate the nuclear fuel recycling processes, the transfer percentages for Pd, Mo, Te, and Sb should be determined. Each element solution containing NaNO3 or HNO3 was fed consistently into the thin film evaporator regulated in vac and at 50 °C. The analyte percentages in the inside of the lid, in the condenser, and in the distillate were 10-1%/m2, 10-3%/m2, and 10-3% (DF = 105), respectively. The Mo percentage in the condenser was lower by a factor of 10 than those of other elements investigated. The NO3
- percentages were nearly constant despite increasing HNO3 concentrations, however, the ratios decreased with increasing NaNO3 concentrations. 相似文献
33.
Iwao Ojima Shin-Ichi Inaba Tetsuo Kogure Makoto Matsumoto Hideyuki Matsumoto Hamao Watanabe Yoichiro Nagai 《Journal of organometallic chemistry》1973,55(1):C4-C6
[RhCl(PPh3)3] is a very effective catalyst for the cleavage of Si-Si bonds by alcohols. 相似文献
34.
35.
A chiral HWE reagent reacted with an alternative carbonyl group of meso-α-diketones of bicyclo[2.2.1] system to give non-racemic (Z)- and (E)-olefins, respectively. 相似文献
36.
Akira Watanabe 《Tetrahedron letters》2004,45(33):6229-6233
Oxovanadium(V)(salen) complex 4 was found to catalyze Meerwein-Ponndorf-Verley cyanation of aliphatic aldehydes with good to high enantioselectivity. This cyanation showed a positive nonlinear effect. 相似文献
37.
38.
Watanabe M Sue K Adschiri T Inomata H Smith RL Arai K 《Chemical communications (Cambridge, England)》2001,(21):2270-2271
In supercritical water the rate of methanol oxidation was controlled by ionic behavior as follows: the oxidation rate of methanol decreased with increasing proton and hydroxide ion concentration, possibly due to stabilization of the reactant, while that of CO was suppressed by added protons and enhanced by added hydroxide ions. 相似文献
39.
N Kubodera H Watanabe T Kawanishi M Matsumoto 《Chemical & pharmaceutical bulletin》1992,40(6):1494-1499
Six analogues of 1 alpha,25-dihydroxy-22-oxavitamin D3 (OCT) (2), 26,27-dimethyl OCT (5), 26,27-diethyl OCT (6), 24-norOCT (7), 24-homoOCT (8), 24-dihomoOCT (9), and 24-trihomoOCT (10) were synthesized from the 20(S)-alcohol (11) as the common starting material. In the activity inducing differentiation of human myeloid leukemia cells (HL-60) into macrophages, 26,27-dimethyl OCT (5) and 24-homoOCT (8) showed the highest activities. The binding properties of these analogues to the chick embryonic intestinal 1 alpha,25-dihydroxyvitamin D3 (1) receptor are also described. 相似文献
40.
A sensitive and specific method using gas chromatography and negative-ion chemical ionization mass spectrometry is described for the determination of 5-fluoro-2'-deoxyuridine (FdUrd) in plasma. The method is based on the formation of the pentafluoropropionyl derivative of FdUrd and of its stable isotope as internal standard after sample clean-up by solid-phase extraction and purification by high-performance liquid chromatography. Quantification in plasma was possible down to 300 pg/ml. The method was applied to the analysis of plasma levels of FdUrd in mice and dogs. 相似文献