全文获取类型
收费全文 | 31215篇 |
免费 | 5056篇 |
国内免费 | 3478篇 |
专业分类
化学 | 22349篇 |
晶体学 | 345篇 |
力学 | 1971篇 |
综合类 | 135篇 |
数学 | 3189篇 |
物理学 | 11760篇 |
出版年
2024年 | 110篇 |
2023年 | 648篇 |
2022年 | 1134篇 |
2021年 | 1163篇 |
2020年 | 1237篇 |
2019年 | 1204篇 |
2018年 | 1103篇 |
2017年 | 979篇 |
2016年 | 1555篇 |
2015年 | 1488篇 |
2014年 | 1861篇 |
2013年 | 2308篇 |
2012年 | 2819篇 |
2011年 | 2856篇 |
2010年 | 1999篇 |
2009年 | 1790篇 |
2008年 | 2069篇 |
2007年 | 1844篇 |
2006年 | 1643篇 |
2005年 | 1438篇 |
2004年 | 1032篇 |
2003年 | 873篇 |
2002年 | 835篇 |
2001年 | 644篇 |
2000年 | 597篇 |
1999年 | 568篇 |
1998年 | 489篇 |
1997年 | 429篇 |
1996年 | 449篇 |
1995年 | 406篇 |
1994年 | 369篇 |
1993年 | 276篇 |
1992年 | 275篇 |
1991年 | 239篇 |
1990年 | 213篇 |
1989年 | 183篇 |
1988年 | 129篇 |
1987年 | 98篇 |
1986年 | 84篇 |
1985年 | 70篇 |
1984年 | 51篇 |
1983年 | 36篇 |
1982年 | 29篇 |
1981年 | 23篇 |
1980年 | 26篇 |
1976年 | 10篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1973年 | 7篇 |
1957年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
81.
Suvarna H. Pagire Haushabhau S. Pagire Kun-Young Park Eun Jung Bae Kwang-eun Kim Minhee Kim Jihyeon Yoon Saravanan Parameswaran Jun-Ho Choi Sungmi Park Jae-Han Jeon Jin Sook Song Myung Ae Bae In-Kyu Lee Hail Kim Jae Myoung Suh Jin Hee Ahn 《Molecules (Basel, Switzerland)》2022,27(11)
Serotonin (5-hydroxytryptophan) is a hormone that regulates emotions in the central nervous system. However, serotonin in the peripheral system is associated with obesity and fatty liver disease. Because serotonin cannot cross the blood-brain barrier (BBB), we focused on identifying new tryptophan hydroxylase type I (TPH1) inhibitors that act only in peripheral tissues for treating obesity and fatty liver disease without affecting the central nervous system. Structural optimization inspired by para-chlorophenylalanine (pCPA) resulted in the identification of a series of oxyphenylalanine and heterocyclic phenylalanine derivatives as TPH1 inhibitors. Among these compounds, compound 18i with an IC50 value of 37 nM was the most active in vitro. Additionally, compound 18i showed good liver microsomal stability and did not significantly inhibit CYP and Herg. Furthermore, this TPH1 inhibitor was able to actively interact with the peripheral system without penetrating the BBB. Compound 18i and its prodrug reduced body weight gain in mammals and decreased in vivo fat accumulation. 相似文献
82.
Jie Tang Yang Yang Jingjing Qu Wenhuang Ban Hao Song Zhengying Gu Yannan Yang Larry Cai Shevanuja Theivendran Yue Wang Min Zhang Chengzhong Yu 《Chemical science》2022,13(29):8507
Pyroptosis is a programmed cell death widely studied in cancer cells for tumour inhibition, but rarely in dendritic cell (DC) activation for vaccine development. Here, we report the synthesis of sodium stabilized mesoporous aluminosilicate nanoparticles as DC pyroptosis modulators and antigen carriers. By surface modification of sodium-stabilized four-coordinate aluminium species on dendritic mesoporous silica nanoparticles, the resultant Na-IVAl-DMSN significantly activated DC through caspase-1 dependent pyroptosis via pH responsive intracellular ion exchange. The released proinflammatory cellular contents further mediated DC hyperactivation with prolonged cytokine release. In vivo studies showed that Na-IVAl-DMSN induced enhanced cellular immunity mediated by natural killer (NK) cells, cytotoxic T cells, and memory T cells as well as humoral immune response. Our results provide a new principle for the design of next-generation nanoadjuvants for vaccine applications.Na-IVAl-DMSN acts as both antigen carriers and modulators to “hyperactivate” dendritic cells (DCs) via potassium (K+) efflux dependent pyroptosis, eventually leading to enhanced adaptive and innate immunity. 相似文献
83.
Kewang Luo Ning Li Wei Ye Hanchao Gao Xinle Luo Baohui Cheng 《Molecules (Basel, Switzerland)》2022,27(14)
Stimulator of interferon gene (STING), an intracellular receptor in the endoplasmic reticulum, could induce the production of cytokines such as type I interferon (IFN) by activating the cGAS-STING signal pathway. In recent years, activation of STING has shown great potential to enhance anti-tumor immunity and reshape the tumor microenvironment, which is expected to be used in tumor immunotherapy. A number of STING agonists have demonstrated promising biological activity and showed excellent synergistic anti-tumor effects in combination with other cancer therapies in preclinical studies and some clinical trials. The combination of STING agonists and ICI also showed a potent effect in improving anti-tumor immunity. In this review, we introduce the cGAS-STING signaling pathway and its effect in tumor immunity and discuss the recent strategies of activation of the STING signaling pathway and its research progress in tumor immunotherapy. 相似文献
84.
Bingbo Wang Xiujuan Ma Cunchi Wang Mingjie Zhang Qianhua Gong Lin Gao 《Entropy (Basel, Switzerland)》2022,24(7)
The determination of directed control paths in complex networks is important because control paths indicate the structure of the propagation of control signals through edges. A challenging problem is to identify them in complex networked systems characterized by different types of interactions that form multilayer networks. In this study, we describe a graph pattern called the conserved control path, which allows us to model a common control structure among different types of relations. We present a practical conserved control path detection method (CoPath), which is based on a maximum-weighted matching, to determine the paths that play the most consistent roles in controlling signal transmission in multilayer networks. As a pragmatic application, we demonstrate that the control paths detected in a multilayered pan-cancer network are statistically more consistent. Additionally, they lead to the effective identification of drug targets, thereby demonstrating their power in predicting key pathways that influence multiple cancers. 相似文献
85.
Tianyou Chen Wenyu Zhang Yuxin Liu Yuqiu Song Liyan Wu Cuihong Liu Tieliang Wang 《Molecules (Basel, Switzerland)》2022,27(14)
To explore the drying characteristics of soybean dregs and a nondestructive moisture content test method, in this study, soybean dregs were dried with hot air (80 °C), the moisture content was measured using the drying method, water status was analyzed using low-field nuclear magnetic resonance (LF-NMR) and the moisture content prediction models were built and validated. The results revealed that the moisture contents of the soybean dregs were 0.57 and 0.01 g/g(w.b.), respectively, after drying for 5 and 7 h. The effective moisture diffusivity increased with the decrease in moisture content; it ranged from 5.27 × 10−9 to 6.96 × 10−8 m2·s−1. Soybean dregs contained bound water (T21), immobilized water (T22) and free water (T23 and T23’). With the proceeding of drying, all of the relaxation peaks shifted left until a new peak (T23’) appeared; then, the structure of soybean dregs changed, and the relaxation peaks reformed, and the peak shifted left again. The peak area may predict the moisture content of soybean dregs, and the gray values of images predict the moisture contents mainly composed of free water or immobilized water. The results may provide a reference for drying of soybean dregs and a new moisture detection method. 相似文献
86.
This paper investigates the scattering effect of
domestic 0.5 at{\%} ceramic Nd:YAG. An effective method has been
utilized to measure the scattering and absorption coefficients.
An end-pumped continuous wave (CW) Nd:YAG ceramic laser was also
demonstrated. A maximum output power of 6.7~W at 1064~nm was
obtained at an 808-nm pump power of 32.9~W. Conversion efficiency
and slope efficiency have been achieved. This indicates that
scattering has an important effect on the optical performance of
ceramic Nd:YAG. 相似文献
87.
An sp2-sp3 hybrid carbon allotrope named HSH-carbon is proposed by the first-principles calculations. The structure of HSH-carbon can be regarded as a template polymerization of [1.1.1]propellane molecules in a hexagonal lattice, as well as, an AA stacking of recently reported HSH-C10 consisting of carbon trigonal bipyramids. Based on calculations, the stability of this structure is demonstrated in terms of the cohesive energy, phonon dispersion, Born−Huang stability criteria, and ab initio molecular dynamics. HSH-carbon is predicted to be a semiconductor with an indirect energy gap of 3.56 eV at the PBE level or 4.80 eV at the HSE06 level. It is larger than the gap of Si and close to the gap of c-diamond, which indicates HSH-carbon is potentially an ultrawide bandgap semiconductor. The effective masses of carriers in the VB and CB edge are comparable with wide bandgap semiconductors such as GaN and ZnO. The elastic behavior of HSH-carbon such as bulk modulus, Young’s modulus and shear modulus is comparable with that of T-carbon and much smaller than that of c-diamond, which suggests that HSH-carbon would be much easier to be processed than c-diamond in practice. 相似文献
88.
Polyoxometalate (POM) presents great potential in oxidative desulfurization (ODS) reaction. However, the high dissolubility of POM in common solvents makes it difficult to recycle. Besides, the small specific surface area of POM also limits the interaction between them and the substrate. Depositing polyoxometalates onto three-dimensional (3D) network structured materials could largely expand the application of POM. Here, the surfaces of cellulose nanofibrils (CNFs) were modified with very few (3-Aminopropyl) trimethoxysilane (APTS) to endow positive charges on the surfaces of CNFs, and then phosphotungstic acid (PTA) was loaded to obtain the aerogel A-CNF/PTA as the ODS catalyst. FT-IR indicated the successful deposition of PTA onto aminosilane modified CNF surfaces. UV-VIS further suggested the stability of PTA in the aerogels. BET and SEM results suggested the increased specific surface area and the relatively uniform 3D network structure of the prepared aerogels. TGA analysis indicated that the thermal stability of the aerogel A-CNF/PTA50% was a little higher than that of the pure CNF aerogel. Most importantly, the aerogel A-CNF/PTA50% showed good catalytic performance for ODS. Catalysis results showed that the substrate conversion rate of the aerogel A-CNF/PTA50% reached 100% within 120 min at room temperature. Even after five cycles, the substrate conversion rate of the aerogel A-CNF/PTA50% still reached 91.2% during the dynamic catalytic process. This work provides a scalable and facile way to stably deposit POM onto 3D structured materials. 相似文献
89.
Lirong Guo Qing Gao Jieqiong Zhu Xiaobao Jin Hui Yin Tao Liu 《Molecules (Basel, Switzerland)》2022,27(9)
Commonly used clinical chemotherapy drugs, such as cyclophosphamide (CTX), may cause injury to the ovaries. Hormone therapies can reduce the ovarian injury risk; however, they do not achieve the desired effect and have obvious side effects. Therefore, it is necessary to find a potential therapeutic candidate for ovarian injury after chemotherapy. N-Benzyl docosahexaenamide (NB-DHA) is a docosahexaenoic acid derivative. It was recently identified as the specific macamide with a high degree of unsaturation in maca (Lepidium meyenii). In this study, the purified NB-DHA was administered intragastrically to the mice with CTX-induced ovarian injury at three dose levels. Blood and tissue samples were collected to assess the regulation of NB-DHA on ovarian function. The results indicated that NB-DHA was effective in improving the disorder of estrous cycle, and the CTX+NB-H group can be recovered to normal levels. NB-DHA also significantly increased the number of primordial follicles, especially in the CTX+NB-M and CTX+NB-H groups. Follicle-stimulating hormone and luteinizing hormone levels in all treatment groups and estradiol levels in the CTX+NB-H group returned to normal. mRNA expression of ovarian development-related genes was positive regulated. The proportion of granulosa cell apoptosis decreased significantly, especially in the CTX+NB-H group. The expression of anti-Müllerian hormone and follicle-stimulating hormone receptor significantly increased in ovarian tissues after NB-DHA treatment. NB-DHA may be a promising agent for treating ovarian injury. 相似文献
90.
Xin Liang Li Li Yan Dong Wei Dong Hongxia Cui Chunhui Xia Tao Xu Chaozhong Wang Jie Zhang Tingting Liu Huimin Sui Chao Gao 《Molecules (Basel, Switzerland)》2022,27(9)
Estrogens added illegally to dietary supplements are hazardous to human health. Traditional detection and analysis methods have many limitations, and we have developed an assay that combines thin-layer chromatography with Raman imaging microscopy (TLC-RIM). The five estrogens (estrone, estradiol, estriol, ethinyl estradiol, and diethylstilbestrol) were initially separated by TLC, then detected by area scanning Raman imaging with a 532 nm laser under a microscope. Raman spectra were obtained for each estrogen, which were used for detecting estrogen illegally added to botanical dietary supplements. The LOD of each estrogen was 0.4, 1.0, 0.8, 0.2, and 0.2 mg/mL, respectively. The matrix in the real sample did not interfere with the detection of estrogens. The method was fast, sensitive, stable, specific, and reliable. 相似文献