全文获取类型
收费全文 | 124670篇 |
免费 | 9777篇 |
国内免费 | 6924篇 |
出版年
2024年 | 141篇 |
2023年 | 1311篇 |
2022年 | 3005篇 |
2021年 | 5647篇 |
2020年 | 3680篇 |
2019年 | 4534篇 |
2018年 | 4554篇 |
2017年 | 3372篇 |
2016年 | 4890篇 |
2015年 | 7152篇 |
2014年 | 8401篇 |
2013年 | 9055篇 |
2012年 | 10872篇 |
2011年 | 9817篇 |
2010年 | 6063篇 |
2009年 | 5343篇 |
2008年 | 6404篇 |
2007年 | 5744篇 |
2006年 | 5184篇 |
2005年 | 4140篇 |
2004年 | 3781篇 |
2003年 | 3376篇 |
2002年 | 3083篇 |
2001年 | 2184篇 |
2000年 | 1974篇 |
1999年 | 2007篇 |
1998年 | 1249篇 |
1997年 | 1311篇 |
1996年 | 1147篇 |
1995年 | 1044篇 |
1994年 | 1076篇 |
1993年 | 829篇 |
1992年 | 1108篇 |
1991年 | 958篇 |
1990年 | 729篇 |
1989年 | 644篇 |
1988年 | 585篇 |
1987年 | 512篇 |
1986年 | 477篇 |
1985年 | 518篇 |
1984年 | 321篇 |
1983年 | 311篇 |
1982年 | 272篇 |
1981年 | 256篇 |
1980年 | 224篇 |
1979年 | 191篇 |
1978年 | 172篇 |
1977年 | 151篇 |
1974年 | 173篇 |
1973年 | 136篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
141.
The assembly of high voltage-activated Ca2+ channels with different β subunits influences channel properties and possibly subcellular targeting. We studied β subunit expression in the somata and axon terminals of the magnocellular neurosecretory cells, which are located in the supraoptic nucleus (SON) and neurohypophysis, respectively. Antibodies directed against the 4 CaVβ subunits (CaVβ1-CaVβ4) were used for immunoblots and for immunostaining of slices of these two tissues. We found that all 4 β subunits are expressed in both locations, but that CaVβ2 had the highest relative expression in the neurohypophysis. These data suggest that the CaVβ2 subunit is selectively targeted to axon terminals and may play a role in targeting and/or regulating the properties of Ca2+ channels. 相似文献
142.
143.
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
144.
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
145.
146.
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
147.
148.
149.
150.
Alan C. L. Yu 《PloS one》2010,5(8)
Variation is a ubiquitous feature of speech. Listeners must take into account context-induced variation to recover the interlocutor''s intended message. When listeners fail to normalize for context-induced variation properly, deviant percepts become seeds for new perceptual and production norms. In question is how deviant percepts accumulate in a systematic fashion to give rise to sound change (i.e., new pronunciation norms) within a given speech community. The present study investigated subjects'' classification of /s/ and // before /a/ or /u/ spoken by a male or a female voice. Building on modern cognitive theories of autism-spectrum condition, which see variation in autism-spectrum condition in terms of individual differences in cognitive processing style, we established a significant correlation between individuals'' normalization for phonetic context (i.e., whether the following vowel is /a/ or /u/) and talker voice variation (i.e., whether the talker is male or female) in speech and their “autistic” traits, as measured by the Autism Spectrum Quotient (AQ). In particular, our mixed-effect logistic regression models show that women with low AQ (i.e., the least “autistic”) do not normalize for phonetic coarticulation as much as men and high AQ women. This study provides first direct evidence that variability in human''s ability to compensate for context-induced variations in speech perceptually is governed by the individual''s sex and cognitive processing style. These findings lend support to the hypothesis that the systematic infusion of new linguistic variants (i.e., the deviant percepts) originate from a sub-segment of the speech community that consistently under-compensates for contextual variation in speech. 相似文献