首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   109764篇
  免费   8510篇
  国内免费   6851篇
  2024年   139篇
  2023年   1282篇
  2022年   2487篇
  2021年   5434篇
  2020年   3575篇
  2019年   4382篇
  2018年   4359篇
  2017年   3235篇
  2016年   4605篇
  2015年   6693篇
  2014年   7876篇
  2013年   8334篇
  2012年   9977篇
  2011年   8880篇
  2010年   5449篇
  2009年   4756篇
  2008年   5598篇
  2007年   4928篇
  2006年   4381篇
  2005年   3337篇
  2004年   2944篇
  2003年   2538篇
  2002年   2210篇
  2001年   2003篇
  2000年   1864篇
  1999年   1845篇
  1998年   1019篇
  1997年   1141篇
  1996年   1019篇
  1995年   921篇
  1994年   946篇
  1993年   666篇
  1992年   993篇
  1991年   840篇
  1990年   614篇
  1989年   559篇
  1988年   486篇
  1987年   412篇
  1986年   389篇
  1985年   390篇
  1984年   213篇
  1983年   198篇
  1982年   138篇
  1981年   118篇
  1980年   107篇
  1979年   115篇
  1978年   78篇
  1977年   60篇
  1974年   74篇
  1972年   62篇
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
121.
  相似文献   
122.
Lin  Xiang  Lin  Shuang  Liu  Yuanlan  Zhao  Haiyan  Wang  Li  Hasi  Wuliji 《Plasmonics (Norwell, Mass.)》2018,13(5):1749-1758
Plasmonics - Large-scale ordered two-dimensional (2D) superlattices at oil/water interface were fabricated using single-crystal Au nanospheres (NSs) with different diameters as building blocks. A...  相似文献   
123.
Many studies have verified that microRNAs contribute a lot to neuropathic pain progression. Furthermore, nerve-related inflammatory cytokines play vital roles in neuropathic pain progression. miR-183 has been identified to have a common relationship with multiple pathological diseases. However, the potential effects of miR-183 in the process of neuropathic pain remain undetermined. Therefore, we performed the current study with the purpose of finding the functions of miR-183 in neuropathic pain progression using a chronic sciatic nerve injury (CCI) rat model. We demonstrated that miR-183 expression levels were evidently reduced in CCI rats in contrast with the control group. Overexpression of miR-183 produced significant relief of mechanical hyperalgesia, as well as thermal hyperalgesia in CCI rats. Furthermore, neuropathic pain-correlated inflammatory cytokine expression levels containing interleukin-6 (IL-6) and interleukin-1β (IL-1β), cyclooxygenase-2 (COX-2) were obviously inhibited by upregulation of miR-183. Meanwhile, dual-luciferase reporter assays showed MAP3K4 was a direct downstream gene of miR-183. The expression levels of MAP3K4 were modulated by the increased miR-183 negatively, which lead to the downregulation of IL-6, IL-1β, and COX-2, and then reduced neuropathic pain progression, respectively. Overall, our study pointed out that miR-183 was a part of the negative regulator which could relieve neuropathic pain by targeting MAP3K4. Thus it may provide a new clinical treatment for neuropathic pain patients clinical therapy.  相似文献   
124.
Pluripotent stem cells (PSCs) are cells that can differentiate into any type of cells in the body, therefore have valuable promise in regenerative medicine of cell replacement therapies and tissue/organ engineering. PSCs can be derived either from early embryos or directly from somatic cells by epigenetic reprogramming that result in customized cells from patients. Here we summarize the methods of deriving PSCs, the various types of PSCs generated with different status, and their versatile applications in both clinical and embryonic development studies. We also discuss an intriguing potential application of PSCs in constructing tissues/organs in large animals by interspecies chimerism. All these emerging findings are likely to contribute to the breakthroughs in biological research and the prosperous prospects of regenerative medicine.  相似文献   
125.
126.
RIG-1 signalling is responsible for the detection of cytoplasmic viral RNA molecules. DEXH (Asp-Glu-X-His) box polypeptide 58 (encoded by DHX58) is a negative regulator of the RIG-1 signalling pathway. In human, the DHX58 gene can be upregulated and can inhibit the RIG-1 signalling pathway during viral infection. In this study, porcine DHX58 gene expression patterns were studied. According to our results, the porcine DHX58 gene was upregulated not only by the stimulation of Poly I:C but also by the stimulation of 1ipopolysaccharides (LPS). One polymorphism (g.4919G>C), detected in the ninth intron, was significantly associated with some blood parameters including the red cell distribution width of 1-day-old pigs and white blood cell counts, lymphocyte absolute counts, and platelet distribution width of 17-day-old pigs (P < 0.05). Moreover, the individuals with the genotype GG have a significantly higher mean white blood cell count than individuals with genotype CC or GC (P < 0.05). Our study indicates that DHX58 is an important gene that is associated with the immune response in swine.  相似文献   
127.
Embryos of most fish develop externally and are exposed to an aquatic environment full of potential pathogens, whereas they have little or only limited ability to mount an efficient and protective response. How fish embryos survive pathogenic attacks remains poorly defined. Here we demonstrate that the maternal immunization of female zebrafish with formalin-killed Aeromonas hydrophila causes a significant increase in C3 and Bf contents in the mother, a corresponding rise in the offspring, and induces a remarkable increase in the hemolytic activities in both the mother and offspring. In addition, the embryos derived from the immunized mother are significantly more tolerant to A. hydrophila challenge than those from the unimmunized fish, and blocking C3 and Bf activities by injection of the antibodies against C3 and Bf into the embryos render them more susceptible to A. hydrophila. These results clearly show that the protection of zebrafish embryos against A. hydrophila can be achieved by the maternally-transferred immunity of the complement system operating via the alternative pathway. This appears to be the first report providing in vivo evidences for the protective role of the alternative complement components in the early embryos of zebrafish, paving the way for insights into the in vivo function of other maternally-transferred factors in fish.  相似文献   
128.
129.
130.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号