全文获取类型
收费全文 | 5480篇 |
免费 | 417篇 |
国内免费 | 314篇 |
出版年
2024年 | 10篇 |
2023年 | 79篇 |
2022年 | 152篇 |
2021年 | 261篇 |
2020年 | 194篇 |
2019年 | 227篇 |
2018年 | 215篇 |
2017年 | 193篇 |
2016年 | 305篇 |
2015年 | 339篇 |
2014年 | 383篇 |
2013年 | 448篇 |
2012年 | 518篇 |
2011年 | 441篇 |
2010年 | 257篇 |
2009年 | 207篇 |
2008年 | 292篇 |
2007年 | 228篇 |
2006年 | 195篇 |
2005年 | 176篇 |
2004年 | 182篇 |
2003年 | 132篇 |
2002年 | 141篇 |
2001年 | 82篇 |
2000年 | 48篇 |
1999年 | 73篇 |
1998年 | 48篇 |
1997年 | 54篇 |
1996年 | 38篇 |
1995年 | 30篇 |
1994年 | 32篇 |
1993年 | 21篇 |
1992年 | 33篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 15篇 |
1988年 | 16篇 |
1987年 | 13篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 13篇 |
1983年 | 20篇 |
1982年 | 4篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 6篇 |
排序方式: 共有6211条查询结果,搜索用时 15 毫秒
51.
52.
53.
The psychrophile Clostridium sp. strain 69 contains a thermolabile triose phosphate isomerase which is inactivated rapidly in vitro and in vivo at 32 C. 相似文献
54.
Cancan Du Xixi Duan Xiaohan Yao Jiajia Wan Yanru Cheng Yuan Wang Yan Yan Lijing Zhang Linyu Zhu Chen Ni Ming Wang Zhihai Qin 《Journal of cellular and molecular medicine》2020,24(14):7802-7813
Tumour‐derived exosomes have been shown to induce pre‐metastatic niche formation, favoring metastatic colonization of tumour cells, but the underlying molecular mechanism is still not fully understood. In this study, we showed that exosomes derived from the LLC cells could indeed significantly enhance their intrapulmonary colonization. Circulating LLC‐derived exosomes were mainly engulfed by lung fibroblasts and led to the NF‐κB signalling activation. Further studies indicated that the exosomal miR‐3473b was responsible for that by hindering the NFKB inhibitor delta's (NFKBID) function. Blocking miR‐3473b could reverse the exosome‐mediated NF‐κB activation of fibroblasts and decrease intrapulmonary colonization of lung tumour cells. Together, this study demonstrated that the miR‐3473b in exosomes could mediate the interaction of lung tumour cells and local fibroblasts in metastatic sites and, therefore, enhance the metastasis of lung tumour cells. 相似文献
55.
Xuan Che Jianzhang Wang Jiayi He Qin Yu Wenting Sun Shuyi Chen Gen Zou Tiantian Li Xinyue Guo Xinmei Zhang 《Journal of cellular and molecular medicine》2020,24(2):1724-1737
Adenomyosis is also called internal endometriosis and affects about 20% of reproductive‐aged women. It seriously reduces life quality of patients because current drug therapies face with numerous challenges. Long‐term clinical application of mifepristone exhibits wonderful therapeutic effects with mild side‐effects in many disorders since 1982. Since adenomyosis is a refractory disease, we investigate whether mifepristone can be applied in the treatment of adenomyosis. In this study, we investigated the direct effects of mifepristone on human primary eutopic endometrial epithelial cells and stromal cells in adenomyosis. We found that mifepristone causes cell cycle arrest through inhibiting CDK1 and CDK2 expressions and induces cell apoptosis via the mitochondria‐dependent signalling pathway in endometrial epithelial cells and stromal cells of adenomyosis. Furthermore, mifepristone inhibits the migration of endometrial epithelial cells and stromal cells through decreasing CXCR4 expression and restricts the invasion of endometrial epithelial cells via suppression of epithelial‐mesenchymal transition in adenomyosis. We also found that mifepristone treatment decreases the uterine volume, CA125 concentration and increases the haemoglobin concentration in serum for adenomyosis patients. Therefore, we demonstrate that mifepristone could serve as a novel therapeutic drug in the treatment of adenomyosis, and therefore, the old dog can do a new trick. 相似文献
56.
Wenjing Yu Kaiju Sun Liying Zhang Xilin Wan Changbao Chen Rui Su Yifei Liu Hongfeng Wang Hongmei Yang 《化学与生物多样性》2020,17(8)
Squalene has been used as a dietary supplement for a long history due to its potential cancer‐preventive function. However, the mechanism has not been investigated in detail yet. Therefore, the aim of this study is to see if the plasma coenzyme Q10 (CoQ10) level will be altered by gavage of squalene and oxidosqualenes to rats. In the present work, a sensitive and simple high‐performance analytical method based on ultra‐high‐performance liquid chromatography coupled with an Orbitrap mass spectrometry (UPLC‐Orbitrap‐MS) was developed for the quantification of CoQ10 in rat plasma. Coenzyme Q9 (CoQ9) was employed as the internal standard. CoQ10 was determined after acetonitrile‐mediated plasma protein precipitation using UPLC‐Orbitrap‐MS in negative ion mode. Intragastric administration of squalene and the two squalene epoxides into rats once daily for several days elevated the level of CoQ10 in their plasma, but there was no significant difference between high‐dose (286 mg/kg) and low‐dose (143 mg/kg) groups. Intragastric administration of squalene once a day for 5 consecutive days and oxidosqualenes once a day for 3 consecutive days is necessary for reaching the steady‐state level of CoQ10. Our present findings indicate that squalene and oxidosqualenes may be useful for stimulating the synthesis of CoQ10 in rats. 相似文献
57.
Young Moon Choi Byoung Wan Lee Myung Sun Jung Hyun Soo Han Suk Hyun Kim Kaifeng Chen Dong Ha Kim Tony F. Heinz Shanhui Fan Jihye Lee Gi‐Ra Yi Jung Kyu Kim Jong Hyeok Park 《Liver Transplantation》2020,10(22)
N‐type metal oxides such as hematite (α‐Fe2O3) and bismuth vanadate (BiVO4) are promising candidate materials for efficient photoelectrochemical water splitting; however, their short minority carrier diffusion length and restricted carrier lifetime result in undesired rapid charge recombination. Herein, a 2D arranged globular Au nanosphere (NS) monolayer array with a highly ordered hexagonal hole pattern (hereafter, Au array) is introduced onto the surface of photoanodes comprised of metal oxide films via a facile drying and transfer‐printing process. Through plasmon‐induced resonance energy transfer, the Au array provides a strong electromagnetic field in the near‐surface area of the metal oxide film. The near‐field coupling interaction and amplification of the electromagnetic field suppress the charge recombination with long‐lived photogenerated holes and simultaneously enhance the light harvesting and charge transfer efficiencies. Consequently, an over 3.3‐fold higher photocurrent density at 1.23 V versus reversible hydrogen electrode (RHE) is achieved for the Au array/α‐Fe2O3. Furthermore, the high versatility of this transfer printing of Au arrays is demonstrated by introducing it on the molybdenum‐doped BiVO4 film, resulting in 1.5‐fold higher photocurrent density at 1.23 V versus RHE. The tailored metal film design can provide a potential strategy for the versatile application in various light‐mediated energy conversion and optoelectronic devices. 相似文献
58.
59.
Xiaofang Lu Qihao Zhang Jincheng Liao Hongyi Chen Yuchi Fan Juanjuan Xing Shijia Gu Jilong Huang Jiaxin Ma Jiancheng Wang Lianjun Wang Wan Jiang 《Liver Transplantation》2020,10(2)
The (Bi,Sb)2Te3 (BST) compounds have long been considered as the benchmark of thermoelectric (TE) materials near room temperature especially for refrigeration. However, their unsatisfactory TE performances in wide‐temperature range severely restrict the large‐scale applications for power generation. Here, using a self‐assembly protocol to deliver a homogeneous dispersion of 2D inclusion in matrix, the first evidence is shown that incorporation of MXene (Ti3C2Tx) into BST can simultaneously achieve the improved power factor and greatly reduced thermal conductivity. The oxygen‐terminated Ti3C2Tx with proper work function leads to highly increased electrical conductivity via hole injection and retained Seebeck coefficient due to the energy barrier scattering. Meanwhile, the alignment of Ti3C2Tx with the layered structure significantly suppresses the phonon transport, resulting in higher interfacial thermal resistance. Accordingly, a peak ZT of up to 1.3 and an average ZT value of 1.23 from 300 to 475 K are realized for the 1 vol% Ti3C2Tx/BST composite. Combined with the high‐performance composite and rational device design, a record‐high thermoelectric conversion efficiency of up to 7.8% is obtained under a temperature gradient of 237 K. These findings provide a robust and scalable protocol to incorporate MXene as a versatile 2D inclusion for improving the overall performance of TE materials toward high energy‐conversion efficiency. 相似文献
60.
Lu Wan Cuili Zhang Kunpeng Ge Xueliang Yang Feng Li Wensheng Yan Zhuo Xu Lin Yang Ying Xu Dengyuan Song Jianhui Chen 《Liver Transplantation》2020,10(16)
Defect state passivation and conductivity of materials are always in opposition; thus, it is unlikely for one material to possess both excellent carrier transport and defect state passivation simultaneously. As a result, the use of partial passivation and local contact strategies are required for silicon solar cells, which leads to fabrication processes with technical complexities. Thus, one material that possesses both a good passivation and conductivity is highly desirable in silicon photovoltaic (PV) cells. In this work, a passivation‐conductivity phase‐like diagram is presented and a conductive‐passivating‐carrier‐selective contact is achieved using PEDOT:Nafion composite thin films. A power conversion efficiency of 18.8% is reported for an industrial multicrystalline silicon solar cell with a back PEDOT:Nafion contact, demonstrating a solution‐processed organic passivating contact concept. This concept has the potential advantages of omitting the use of conventional dielectric passivation materials deposited by costly high‐vacuum equipment, energy‐intensive high‐temperature processes, and complex laser opening steps. This work also contributes an effective back‐surface field scheme and a new hole‐selective contact for p‐type and n‐type silicon solar cells, respectively, both for research purposes and as a low‐cost surface engineering strategy for future Si‐based PV technologies. 相似文献