全文获取类型
收费全文 | 3688篇 |
免费 | 437篇 |
国内免费 | 168篇 |
专业分类
化学 | 3407篇 |
晶体学 | 1篇 |
力学 | 61篇 |
综合类 | 46篇 |
数学 | 108篇 |
物理学 | 670篇 |
出版年
2024年 | 14篇 |
2023年 | 107篇 |
2022年 | 560篇 |
2021年 | 479篇 |
2020年 | 277篇 |
2019年 | 167篇 |
2018年 | 111篇 |
2017年 | 172篇 |
2016年 | 217篇 |
2015年 | 199篇 |
2014年 | 183篇 |
2013年 | 273篇 |
2012年 | 210篇 |
2011年 | 164篇 |
2010年 | 126篇 |
2009年 | 145篇 |
2008年 | 132篇 |
2007年 | 120篇 |
2006年 | 92篇 |
2005年 | 71篇 |
2004年 | 67篇 |
2003年 | 65篇 |
2002年 | 33篇 |
2001年 | 38篇 |
2000年 | 52篇 |
1999年 | 30篇 |
1998年 | 23篇 |
1997年 | 29篇 |
1996年 | 15篇 |
1995年 | 22篇 |
1994年 | 23篇 |
1993年 | 9篇 |
1992年 | 17篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有4293条查询结果,搜索用时 35 毫秒
61.
Michael Russelle S. Alvarez Qingwen Zhou Sheryl Joyce B. Grijaldo Carlito B. Lebrilla Ruel C. Nacario Francisco M. Heralde III Jomar F. Rabajante Gladys C. Completo 《Molecules (Basel, Switzerland)》2022,27(12)
Cancer progression is linked to aberrant protein glycosylation due to the overexpression of several glycosylation enzymes. These enzymes are underexploited as potential anticancer drug targets and the development of rapid-screening methods and identification of glycosylation inhibitors are highly sought. An integrated bioinformatics and mass spectrometry-based glycomics-driven glycoproteomics analysis pipeline was performed to identify an N-glycan inhibitor against lung cancer cells. Combined network pharmacology and in silico screening approaches were used to identify a potential inhibitor, pictilisib, against several glycosylation-related proteins, such as Alpha1-6FucT, GlcNAcT-V, and Alpha2,6-ST-I. A glycomics assay of lung cancer cells treated with pictilisib showed a significant reduction in the fucosylation and sialylation of N-glycans, with an increase in high mannose-type glycans. Proteomics analysis and in vitro assays also showed significant upregulation of the proteins involved in apoptosis and cell adhesion, and the downregulation of proteins involved in cell cycle regulation, mRNA processing, and protein translation. Site-specific glycoproteomics analysis further showed that glycoproteins with reduced fucosylation and sialylation were involved in apoptosis, cell adhesion, DNA damage repair, and chemical response processes. To determine how the alterations in N-glycosylation impact glycoprotein dynamics, modeling of changes in glycan interactions of the ITGA5–ITGB1 (Integrin alpha 5-Integrin beta-1) complex revealed specific glycosites at the interface of these proteins that, when highly fucosylated and sialylated, such as in untreated A549 cells, form greater hydrogen bonding interactions compared to the high mannose-types in pictilisib-treated A549 cells. This study highlights the use of mass spectrometry to identify a potential glycosylation inhibitor and assessment of its impact on cell surface glycoprotein abundance and protein–protein interaction. 相似文献
62.
Pnina Fishman 《Molecules (Basel, Switzerland)》2022,27(12)
The A3 adenosine receptor (A3AR) is overexpressed in pathological human cells. Piclidenoson and namodenoson are A3AR agonists with high affinity and selectivity to A3AR. Both induce apoptosis of cancer and inflammatory cells via a molecular mechanism entailing deregulation of the Wnt and the NF-κB signaling pathways. Our company conducted phase I studies showing the safety of these 2 molecules. In the phase II studies in psoriasis patients, piclidenoson was safe and demonstrated efficacy manifested in significant improvements in skin lesions. Namodenoson is currently being developed to treat liver cancer, where prolonged overall survival was observed in patients with advanced liver disease and a Child–Pugh B score of 7. A pivotal phase III study in this patient population has been approved by the FDA and the EMA and is currently underway. Namodenoson is also being developed to treat non-alcoholic steatohepatitis (NASH). A Phase IIa study has been successfully concluded and showed that namodenoson has anti-inflammatory, anti-fibrosis, and anti-steatosis effects. A phase IIb study in NASH is currently enrolling patients. In conclusion, A3AR agonists are promising drug candidates in advanced stages of clinical development and demonstrate safety and efficacy in their targeted indications. 相似文献
63.
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
64.
CHEN Jie DONG Xin-shu GUO Xing-gang The Affiliated Tumor Hospital Harbin Medical University Harbin P. R. China 《高等学校化学研究》2008,24(6)
To explore the functional mechanism of Resveratrol against colon cancer cells Is174t and the growth of colon cancer tissue of tumor-bearing mice,MTT method was used to observe the functions of resveratrol for inhibition against cells ls174t in vitro.Transmission electron microscope was used to observe the cell apoptosis.FCM assay was performed to measure the change of the cell apoptosis rate and of cell cycle,RT-PCR method was used to detect the expressions of bc1-2 and bax mRNA.Western blot method was used to detect the expressions of bc1-2 and bax protein.Cells isi74t were transplanted subcutaneously to nude mice to observe the effect of resveratrol on the growth of subcutaneously transplanted tumor.RT-PCR method was used to detect the expressions of bc1-2 and bax mRNA in the tumor tissue.Western blot method was used to detect the expressions of bc1-2 and bax protein in the tumor tissue.Resveratrol has an effect of inhibiting proliferation of cells ls174t in vitro(P<0.01).It is able to induce the apoptosis of cells Is174t,causing the decrease in the expression of bc1-2 and the increase in the expression of bax.Resveratrol could inhibit the growth of subcutaneously transplanted tumor of nude mice(P<0.05),causing the decrease in the expression of bc1-2 and the increase in the expression of bax.Resveratrol can inhibit the growth of cells 174t and the growth of subcutaneously transplanted tumor.The mechanism is possibly related to the induction of the cell apoptosis and the regulation of bc1-2/bax expression. 相似文献
65.
A CA19-9 electrochemical immunosensor was constructed using a hybrid self-assembled membrane modified with a gold electrode and applied to detect real samples. Hybrid self-assembled membranes were selected for electrode modification and used to detect antigens. First, the pretreated working electrodes were placed in a 3-mercaptopropionic acid (MPA)/β-mercaptoethanol (ME) mixture for 24 h for self-assembly. The electrodes were then placed in an EDC/NHS mixture for 1 h. Layer modification was performed by stepwise dropwise addition of CA19-9 antibody, BSA, and antigen. Differential pulse voltammetry was used to characterize this immunosensor preparation process. The assembled electrochemical immunosensor enables linear detection in the concentration range of 0.05–500 U/mL of CA19-9, and the detection limit was calculated as 0.01 U/mL. The results of the specificity measurement test showed that the signal change of the interfering substance was much lower than the response value of the detected antigen, indicating that the sensor has good specificity and strong anti-interference ability. The repeatability test results showed that the relative standard deviations were less than 5%, showing good accuracy and precision. The CA19-9 electrochemical immunosensor was used for the actual sample detection, and the experimental results of the standard serum addition method showed that the RSD values of the test concentrations were all less than 10%. The recoveries were 102.4–115.0%, indicating that the assay has high precision, good accuracy, and high potential application value. 相似文献
66.
血液可见吸收光谱与血氧参数神经网络估算法 总被引:1,自引:0,他引:1
总血红蛋白浓度和血氧饱和度是两个基本的血氧参数。文章提出了利用内置双光纤微创探头在位测量大鼠脑组织血氧参数的新方法。首先,利用悬乳液(Intralipid)和全血配置不同总血红蛋白浓度的混合溶液,模拟生物组织模型,用光纤光谱仪测试系统测量组织模型在加氧和去氧时的实时吸收光谱,同时用血氧分析仪(OXI meter)对血氧参数定标,建立测试光谱和定标数据样本集。然后,利用人工神经网络建立血液吸收光谱与血氧参数的神经网络模型,训练后的网络模型能根据吸收光谱输出生物组织的血氧参数值,总血红蛋白浓度和血氧饱和度的平均输出误差分别为±4μmol·L-1和±5%。最后,利用神经网络模型对大鼠脑组织血氧参数进行了在位测试实验,测得脑灰质的血氧饱和度为0.60~0.70,脑白质血氧饱和度为0.45~0.55;总血红蛋白浓度在脑皮层(深度1mm)附近最高,平均110μmol·L-1,其余深度脑组织的总血红蛋白浓度为70~90μmol·L-1。这种方法对脑外科微创手术中实时在位测试脑组织血氧参数具有重要的参考意义。 相似文献
67.
Yron Joseph Yabut Manaig Silvia Sandrini Sara Panseri Gabriella Tedeschi Josep M. Folch Armand Snchez Giovanni Savoini Alessandro Agazzi 《Molecules (Basel, Switzerland)》2022,27(9)
Elevated omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) ratios in swine diets can potentially impose a higher risk of inflammatory and metabolic diseases in swine. A low ratio between the two omega PUFAs has beneficial effects on sows’ and piglets’ production performance and immunity status. At present, there are few studies on how sow nutrition directly affects the protein and fat deposition in suckling piglets. Two groups of sows were fed diets with high or low n-6/n-3 polyunsaturated ratios of 13:1 (SOY) and 4:1 (LIN), respectively, during gestation and lactation. Longissimus dorsi muscle and adipose tissue from newborn piglets, nourished only with sow’s milk, were subjected to fatty acid profiling by gas chromatography–mass spectrometry (GC-MS) and to proteomics assays based on nano-liquid chromatography coupled to high-resolution tandem mass spectrometry (nLC-HRMS). Fatty acid profiles on both muscle and adipose tissues resembled the magnitude of the differences between fatty acid across diets. Proteomic analysis revealed overabundance of 4 muscle and 11 adipose tissue proteins in SOY compared to LIN in both piglet tissues. The detected overabundance of haptoglobin, an acute-phase protein, and the stimulation of protein-coding genes and proteins related to the innate immune response and acute inflammatory response could be associated with the pro-inflammatory role of n-6 PUFAs. 相似文献
68.
69.
调制激光作用牙齿组织发生散射形成光子密度波, 而由于光热效应产生热波, 基于一维介质辐射传输漫射近似方程与一维热传导方程建立了调制激光作用牙齿组织半透明混合介质的一维热波数学模型. 利用该模型仿真分析了牙齿龋损特性参数(牙釉质龋损层光吸收系数、散射系数、热扩散系数及龋损深度)对光热辐射动态响应特性的影响与规律. 利用红外探测器(HgCdTe, 2–12 μm)记录808 nm半导体激光激发牙齿组织产生的热波信号, 由锁相放大器计算热波信号的幅值与相位. 通过频率扫描试验获得了牙齿组织的光热动态响应, 利用多参数最佳统计拟合方法得到了牙齿组织特性参数. 结果表明光热辐射测量对牙齿组织不均匀性和龋损特性均具有较高敏感性与特异性. 相似文献
70.
Shiteng Suo Xiaoxi Chen Lianming Wu Xiaofei Zhang Qiuying Yao Yu Fan He Wang Jianrong Xu 《Magnetic resonance imaging》2014