全文获取类型
收费全文 | 11226篇 |
免费 | 183篇 |
国内免费 | 91篇 |
专业分类
化学 | 7539篇 |
晶体学 | 115篇 |
力学 | 554篇 |
综合类 | 3篇 |
数学 | 1315篇 |
物理学 | 1974篇 |
出版年
2024年 | 156篇 |
2023年 | 118篇 |
2022年 | 488篇 |
2021年 | 475篇 |
2020年 | 420篇 |
2019年 | 498篇 |
2018年 | 464篇 |
2017年 | 383篇 |
2016年 | 620篇 |
2015年 | 434篇 |
2014年 | 588篇 |
2013年 | 1071篇 |
2012年 | 824篇 |
2011年 | 779篇 |
2010年 | 565篇 |
2009年 | 455篇 |
2008年 | 498篇 |
2007年 | 442篇 |
2006年 | 312篇 |
2005年 | 320篇 |
2004年 | 194篇 |
2003年 | 193篇 |
2002年 | 161篇 |
2001年 | 88篇 |
2000年 | 57篇 |
1999年 | 65篇 |
1998年 | 44篇 |
1997年 | 52篇 |
1996年 | 49篇 |
1995年 | 36篇 |
1994年 | 42篇 |
1993年 | 21篇 |
1992年 | 39篇 |
1991年 | 35篇 |
1990年 | 31篇 |
1989年 | 36篇 |
1988年 | 35篇 |
1987年 | 34篇 |
1986年 | 31篇 |
1985年 | 38篇 |
1984年 | 36篇 |
1983年 | 22篇 |
1982年 | 28篇 |
1981年 | 19篇 |
1980年 | 23篇 |
1979年 | 21篇 |
1978年 | 21篇 |
1977年 | 14篇 |
1976年 | 18篇 |
1974年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
Structural Chemistry - Ab initio calculations have been performed to study the complexes between the noble gas elements (Ae = Ne, Ar, Kr) with a series of benzene isoelectronic heterocyclic... 相似文献
172.
173.
Muhammad Sulaiman Ali Thangamani Arumgam Ravi Subban 《Research on Chemical Intermediates》2017,43(10):5637-5664
Research on Chemical Intermediates - Eight new series of novel phenothiazine-based chalcone derivatives with various N-substituted rhodanines (10a–g to 17a–g) were synthesized by... 相似文献
174.
Zonozi Fatemeh Beyramabadi S. Ali Pordel Mehdi Morsali Ali 《Research on Chemical Intermediates》2017,43(3):1829-1846
Research on Chemical Intermediates - The derivatives of acridine play important roles as dyes, drugs, and antiseptics. Herein, we have investigated the kinetics and the mechanism of the formation... 相似文献
175.
Chermahini Alireza Najafi Hafizi Hamid Andisheh Nikzad Saraji Mohammad Shahvar Ali 《Research on Chemical Intermediates》2017,43(11):6763-6763
Research on Chemical Intermediates - 相似文献
176.
Microchimica Acta - The authors describe a magnetic nanoadsorbent consisting of magnetite nanoparticles coated first with titanium dioxide and then with polypyrrole (PPy). It is shown to be a... 相似文献
177.
178.
Fahime Bigdeli Christina T. Lollar Ali Morsali Hong‐Cai Zhou 《Angewandte Chemie (International ed. in English)》2020,59(12):4652-4669
In recent years, metal–organic frameworks (MOFs) have become an area of intense research interest because of their adjustable pores and nearly limitless structural diversity deriving from the design of different organic linkers and metal structural building units (SBUs). Among the recent great challenges for scientists include switchable MOFs and their corresponding applications. Switchable MOFs are a type of smart material that undergo distinct, reversible, chemical changes in their structure upon exposure to external stimuli, yielding interesting technological applicability. Although the process of switching shares similarities with flexibility, very limited studies have been devoted specifically to switching, while a fairly large amount of research and a number of Reviews have covered flexibility in MOFs. This Review focuses on the properties and general design of switchable MOFs. The switching activity has been delineated based on the cause of the switching: light, spin crossover (SCO), redox, temperature, and wettability. 相似文献
179.
Vahideh Masoumi Ali Mohammadi Mohsen Amini Mohammad Reza Khoshayand Rasoul Dinarvand 《Journal of Solid State Electrochemistry》2014,18(6):1763-1771
In this work, polyaniline, polypyrrole, and polyaniline/polypyrrole composite fibers were synthesized in the absence and presence of oxidized multiwalled carbon nanotubes using electrochemical cyclic voltammetry with CF3COOH as dopant. Thermal stability of these fibers was studied by differential scanning calorimetry. Then, headspace solid-phase microextraction process coupled with gas chromatography and flame ionization detector was used for comparing extraction capability of benzaldehyde from aqueous solution. Since polyaniline fiber showed better extraction efficiency than the other fibers, its preparation conditions including acid concentration, aniline concentration, scan rate, and amount of multiwalled carbon nanotubes were studied by means of the “one-factor-at-a-time method”. The analytical performance of polyaniline fibers were investigated to determine benzaldehyde from the aqueous solution. The morphology and texture of polyaniline fibers were examined by field emission scanning electron microscopy and Fourier transform infrared spectroscopy analyses. The attained results revealed that the perfect conditions for acid concentration, aniline concentration, scan rate, and multiwalled carbon nanotubes content were 0.5 M, 0.2 M, 25 mV s?1, and 0.02 wt%, respectively. The limit of detection for the proposed polyaniline fiber was 15 ng ml?1. 相似文献
180.
Nasim Vahidfar Amir R. Jalilian Yousef Fazaeli Ali Bahrami-Samani Davood Beiki Ali Khalaj 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(1):269-276
166Ho labeled 5,10,15,20-tetrakis(3,4-dimethoxyphenyl) porphyrin, and 5,10,15,20-tetrakis(3,4,5-trimethoxyphenyl) porphyrin ([166Ho]–TDMPP and [166Ho]–TTMPP respectively) were prepared with acceptable radiochemical purity and specific activities. Stability and partition coefficient of the complexes were determined in the final formulations and biodistribution studies in mouse demonstrated high accumulation of [166Ho]–TDMPP in the lung and liver and less excretion through the kidney. while [166Ho]–TTMPP was mostly excreted into intestines and kidneys while lungs were a minor accumulation site. In contrast to other reported radiolanthanide labeled porphyrins these two complexes showed less liver accumulation. Further investigation of their potential therapeutic properties is of interest. 相似文献