全文获取类型
收费全文 | 11721篇 |
免费 | 1191篇 |
国内免费 | 727篇 |
专业分类
化学 | 7540篇 |
晶体学 | 115篇 |
力学 | 637篇 |
综合类 | 48篇 |
数学 | 1653篇 |
物理学 | 3646篇 |
出版年
2023年 | 168篇 |
2022年 | 194篇 |
2021年 | 337篇 |
2020年 | 389篇 |
2019年 | 380篇 |
2018年 | 346篇 |
2017年 | 282篇 |
2016年 | 490篇 |
2015年 | 438篇 |
2014年 | 498篇 |
2013年 | 853篇 |
2012年 | 908篇 |
2011年 | 947篇 |
2010年 | 616篇 |
2009年 | 564篇 |
2008年 | 665篇 |
2007年 | 553篇 |
2006年 | 553篇 |
2005年 | 473篇 |
2004年 | 383篇 |
2003年 | 366篇 |
2002年 | 309篇 |
2001年 | 270篇 |
2000年 | 235篇 |
1999年 | 208篇 |
1998年 | 140篇 |
1997年 | 136篇 |
1996年 | 145篇 |
1995年 | 112篇 |
1994年 | 134篇 |
1993年 | 107篇 |
1992年 | 102篇 |
1991年 | 97篇 |
1990年 | 90篇 |
1989年 | 68篇 |
1988年 | 57篇 |
1987年 | 53篇 |
1986年 | 56篇 |
1985年 | 81篇 |
1984年 | 71篇 |
1983年 | 47篇 |
1982年 | 69篇 |
1981年 | 57篇 |
1980年 | 57篇 |
1979年 | 51篇 |
1978年 | 58篇 |
1977年 | 50篇 |
1976年 | 46篇 |
1975年 | 38篇 |
1973年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 446 毫秒
1.
Donglei Wei Huili Li Chuanqing Yang Jianmin Fu Hou Chen Liangjiu Bai Wenxiang Wang Huawei Yang Lixia Yang Ying Liang 《Journal of polymer science. Part A, Polymer chemistry》2022,60(10):1588-1594
Acridone as a new kind of visible light photocatalyst has been developed to catalyze metal free atom transfer radical polymerization (ATRP). The photocatalyst possess low excited state potential as can undergo an oxidative quenching pathway to initiate ATRP of vinyl monomers. Kinetic study and light on/off reaction demonstrate the “living”/controlled nature of the polymerization by light. Block copolymers can be achieved by using PMMA as macroinitiator to reinitiate polymerization of other vinyl monomers, which shows highly preserved Br chain-end functionality in the synthesized polymers. Moreover, the polymerization can be conducted under air atmosphere as most photocatalysts need anaerobic condition, which may give inspiration of further application of this kind of photocatalyst. 相似文献
2.
Nanocomposite hydrogel consisting of Na‐montmorillonite with enhanced mechanical properties 下载免费PDF全文
Ting Li Shuangfei Xiang Piming Ma Huiyu Bai Weifu Dong Mingqing Chen 《Journal of Polymer Science.Polymer Physics》2015,53(14):1020-1026
A new kind of nanocomposite (NC) hydrogel with Na‐montmorillonite (MMT) is presented in this article. The NC hydrogels were synthesized by free radical copolymerization of acrylamide and (3‐acrylamidopropyl) trimethylammonium chloride (ATC) in the presence of MMT and N,N′‐methylene‐bis‐acrylamide used as chemical cross‐linker. Due to the cation‐exchange reaction between MMT and ATC (cationic monomer) during the synthesis of NC hydrogels, MMT platelets were considered chemical “plane” cross‐linkers, different from “point” cross‐linkers. With increasing amount of MMT, the crosslinking degree enhanced, causing a decrease of the swelling degree at equilibrium. Investigations of mechanical properties indicated that NC hydrogels exhibited enhanced strength and toughness, which resulted from chemical interaction between exfoliated MMT platelets and polymer chains in hydrogels. Dynamic shear measurements showed that both storage modulus and loss modulus increased with increasing MMT content. The idea described here provided a new route to prepare hydrogels with high mechanical properties by using alternative natural Na‐MMT. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1020–1026 相似文献
3.
Analysis and pharmacokinetic study of polyphyllin H in beagle dog plasma after oral administration of Rhizoma Paridis Extracts by LC‐MS/MS 下载免费PDF全文
4.
5.
Su X. F. Zhang Y. L. Maximov A. L. Zhang K. Xin Q. Feng C. Q. Bai X. F. Wu W. 《Russian Journal of Applied Chemistry》2020,93(1):127-136
Russian Journal of Applied Chemistry - Nanoscale ZSM-5 (AlZ5-D) and Ga-substituted ZSM-5 zeolites ((Al,Ga)Z5-D and GaZ5-D) were synthesized by a green dry-gel conversion strategy. For comparison,... 相似文献
6.
7.
8.
As a new type of quantum dots (QDs), hexagonal boron nitride quantum dots (BNQDs) exhibit promising potential in the applications of disease diagnosis, fluorescence imaging, biosensing, metal ion detection, and so on, because of their remarkable chemical stability, excellent biocompatibility, low cytotoxicity, and outstanding photoluminescence properties. However, the large-scale fabrication of homogeneous BNQDs still remains challenging. In this article, the properties and common fabrication methods of BNQDs are summarized based on the recent research progress. Then, the corresponding yields, morphologies, and fabrication mechanisms of these as-obtained BNQDs are discussed in detail. Moreover, the applications of these as-obtained BNQDs in different fields are also discussed. This article is expected to inspire new methods and improvements to achieve large-scale fabrication of homogeneous BNQDs, which will enable their practical applications in future. 相似文献
9.
Liying Zhang Chuanrui Zhao Yujiao Bai Qian Wang Pan Ma Xiaojie Ma Peihua Zhu 《Electroanalysis》2022,34(2):302-309
The design and exploration of efficient, stable and environmentally compatible organic emitters for an electrochemiluminescence (ECL) sensor is a promising topic. Herein, a novel environmentally-friendly luminophore, ZnBCBTP@MWCNTs, were fabricated via self-assembly of porphyrin molecules (ZnBCBTP) onto multi-walled carbon nanotubes (MWCNTs). The resulting luminophore ZnBCBTP@MWCNTs displayed not only the highly ECL property and but also the good accelerated electron mobility. Then, a label-free ECL biosensor based ZnBCBTP@MWCNTs was constructed for the ultrasensitive detection of uric acid. Excitingly, this proposed ECL biosensor performed a good linear relationship in the range of 0–300 μM with a low detection limit of 1.4 μM, thus offering another reliable and feasible sensing platform for clinical bioanalysis with good selectivity, stability, and repeatability. 相似文献
10.
以1,4-二溴-2,5-二甲基苯和4-吡啶硼酸为原料,经两步合成了一种新颖的含吡啶基团的二羧酸配体。通过核磁共振氢谱及傅里叶变换红外光谱对配体结构进行表征,通过热重分析对配体的热稳定性进行了测试;通过溶剂热法对配体的单晶进行培养,并考察反应温度、时间、pH和溶剂等条件对单晶培养的影响。结果表明:在反应温度为80 ℃,反应时间为12 h、溶剂为蒸馏水、溶液pH=5的条件下可获得高质量单晶。该配体为单斜晶系,属于C2/c空间群,结构中含有4个氧原子和2个氮原子,可为金属离子的配位提供足够的位点,有望应用于配合物的设计或催化、吸附和医药载体等行业。 相似文献