全文获取类型
收费全文 | 1992篇 |
免费 | 84篇 |
国内免费 | 1篇 |
专业分类
2077篇 |
出版年
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 30篇 |
2020年 | 13篇 |
2019年 | 23篇 |
2018年 | 43篇 |
2017年 | 27篇 |
2016年 | 39篇 |
2015年 | 66篇 |
2014年 | 99篇 |
2013年 | 140篇 |
2012年 | 167篇 |
2011年 | 153篇 |
2010年 | 104篇 |
2009年 | 80篇 |
2008年 | 144篇 |
2007年 | 153篇 |
2006年 | 140篇 |
2005年 | 105篇 |
2004年 | 134篇 |
2003年 | 96篇 |
2002年 | 104篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 24篇 |
1998年 | 15篇 |
1997年 | 14篇 |
1996年 | 13篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 4篇 |
1992年 | 11篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有2077条查询结果,搜索用时 15 毫秒
991.
Kazuhiko Seki Tomohiro Kizuka Hiroshi Yamada 《Journal of electromyography and kinesiology》2007,17(2):113-120
We investigated the effects of immobilization on the maximal motoneuronal firing rate recorded from the first dorsal interosseous (FDI) during voluntary isometric contraction. In five human subjects, the middle finger, index finger, and thumb were immobilized for 1 week in a fiber-glass cast, which kept FDI in a shortened position. During a maximal voluntary contraction, single muscle-fiber action potentials were recorded using a tungsten microelectrode, and mean firing rate was calculated for each action-potential train. Three recording sessions were held: before immobilization (pre), after immobilization (post), and after a 1-week recovery period (recovery). The mean firing rate of FDI motoneurons during maximal voluntary contraction was decreased immediately after the 1-week immobilization (pre: 39.0+/-3.2 Hz, number of detected spike trains (n)=353; post: 33.1+/-1.5 Hz, n=285; p<0.05), and there was a return to control after the recovery period (40.2+/-3.4 Hz, n=236). This suggests that the maximal motoneuronal firing rate achieved during maximal voluntary contraction is reduced after short-term immobilization. The functional implications and the contribution of this phenomenon to the immobilization-induced reduction in maximal voluntary force are discussed. 相似文献
992.
Shoko Fujino Sayuri Hamano Atsushi Tomokiyo Tomohiro Itoyama Daigaku Hasegawa Hideki Sugii Shinichiro Yoshida Ayako Washio Aoi Nozu Taiga Ono Naohisa Wada Chiaki Kitamura Hidefumi Maeda 《Journal of cellular physiology》2020,235(5):4376-4387
Dopamine (DA) is produced from tyrosine by tyrosine hydroxylase (TH). A recent study has reported that DA promotes the mineralization of murine preosteoblasts. However, the role of DA in odontoblasts has not been examined. Therefore, in this investigation, we researched the expression of TH and DA in odontoblasts and the effects of DA on the differentiation of preodontoblasts (KN-3 cells). Immunostaining showed that TH and DA were intensely expressed in odontoblasts and preodontoblasts of rat incisors and molars. KN-3 cells expressed D1-like and D2-like receptors for DA. Furthermore, DA promoted odontoblastic differentiation of KN-3 cells, whereas an antagonist of D1-like receptors and a PKA signaling blocker, inhibited such differentiation. However, antagonists of D2-like receptors promoted differentiation. These results suggested that DA in preodontoblasts and odontoblasts might promote odontoblastic differentiation through D1-like receptors, but not D2-like receptors, and PKA signaling in an autocrine or paracrine manner and plays roles in dentinogenesis. 相似文献
993.
994.
Masatoshi Mita Tomohiro Osugi Shin Matsubara Tsuyoshi Kawada Honoo Satake Hidekazu Katayama 《Molecular reproduction and development》2021,88(1):34-42
A relaxin‐like gonad‐stimulating peptide (RGP) in starfish was the first identified invertebrate gonadotropin responsible for final gamete maturation. An RGP ortholog was newly identified from Astropecten scoparius of the order Paxillosida. The A. scoparius RGP (AscRGP) precursor is encoded by a 354 base pair open reading frame and is a 118 amino acid (aa) protein consisting of a signal peptide (26 aa), B‐chain (21 aa), C‐peptide (47 aa), and A‐chain (24 aa). There are three putative processing sites (Lys‐Arg) between the B‐chain and C‐peptide, between the C‐peptide and A‐chain, and within the C‐peptide. This structural organization revealed that the mature AscRGP is composed of A‐ and B‐chains with two interchain disulfide bonds and one intrachain disulfide bond. The C‐terminal residues of the B‐chain are Gln‐Gly‐Arg, which is a potential substrate for formation of an amidated C‐terminal Gln residue. Non‐amidated (AscRGP‐GR) and amidated (AscRGP‐NH2) peptides were chemically synthesized and their effect on gamete shedding activity was examined using A. scoparius ovaries. Both AscRGP‐GR and AscRGP‐NH2 induced oocyte maturation and ovulation in similar dose‐dependent manners. This is the first report on a C‐terminally amidated functional RGP. Collectively, these results suggest that AscRGP‐GR and AscRGP‐NH2 act as a natural gonadotropic hormone in A. scoparius. 相似文献
995.
Takahiro Sato Ichizo Tsujino Hiroshi Ohira Noriko Oyama-Manabe Yoichi M. Ito Teruo Noguchi Asuka Yamada Daisuke Ikeda Taku Watanabe Masaharu Nishimura 《PloS one》2013,8(6)
Background
This study investigated the major clinical determinants of late gadolinium enhancement (LGE) at ventricular insertion points (VIPs) commonly seen in patients with pulmonary hypertension (PH).Methods
Forty-six consecutive PH patients (mean pulmonary artery pressure ≥25 mmHg at rest) and 21 matched controls were examined. Right ventricular (RV) morphology, function and LGE mass volume at VIPs were assessed by cardiac magnetic resonance (CMR). Radial motion of the left ventricular (LV) wall and interventricular septum (IVS) was assessed by speckle-tracking echocardiography. Paradoxical IVS motion index was then calculated. Univariate and multivariate regression analysis were conducted to characterize the relationship between LGE volume at VIPs and PH-related clinical indices, including the paradoxical IVS motion index.Results
Mean pulmonary arterial pressure (MPAP) of PH patients was 38±9 mmHg. LGE at VIPs was observed in 42 of 46 PH patients, and the LGE volume was 2.02 mL (0.47–2.99 mL). Significant correlations with LGE volume at VIPs were observed for MPAP (r = 0.50) and CMR-derived parameters [RV mass index (r = 0.53), RV end-diastolic volume index (r = 0.53), RV ejection fraction (r = −0.56), and paradoxical IVS motion index (r = 0.77)]. In multiple regression analysis, paradoxical IVS motion index alone significantly predicted LGE volume at VIPs (p<0.001).Conclusions
LGE at VIPs seen in patients with PH appears to reflect altered IVS motion rather than elevated RV pressure or remodeling. Long-term studies would be of benefit to characterize the clinical relevance of LGE at VIPs. 相似文献996.
997.
Satoshi Narumi Kumihiro Matsuo Tomohiro Ishii Yusuke Tanahashi Tomonobu Hasegawa 《PloS one》2013,8(3)
Somatic activating GNAS mutations cause McCune-Albright syndrome (MAS). Owing to low mutation abundance, mutant-specific enrichment procedures, such as the peptide nucleic acid (PNA) method, are required to detect mutations in peripheral blood. Next generation sequencing (NGS) can analyze millions of PCR amplicons independently, thus it is expected to detect low-abundance GNAS mutations quantitatively. In the present study, we aimed to develop an NGS-based method to detect low-abundance somatic GNAS mutations. PCR amplicons encompassing exons 8 and 9 of GNAS, in which most activating mutations occur, were sequenced on the MiSeq instrument. As expected, our NGS-based method could sequence the GNAS locus with very high read depth (approximately 100,000) and low error rate. A serial dilution study with use of cloned mutant and wildtype DNA samples showed a linear correlation between dilution and measured mutation abundance, indicating the reliability of quantification of the mutation. Using the serially diluted samples, the detection limits of three mutation detection methods (the PNA method, NGS, and combinatory use of PNA and NGS [PNA-NGS]) were determined. The lowest detectable mutation abundance was 1% for the PNA method, 0.03% for NGS and 0.01% for PNA-NGS. Finally, we analyzed 16 MAS patient-derived leukocytic DNA samples with the three methods, and compared the mutation detection rate of them. Mutation detection rate of the PNA method, NGS and PNA-NGS in 16 patient-derived peripheral blood samples were 56%, 63% and 75%, respectively. In conclusion, NGS can detect somatic activating GNAS mutations quantitatively and sensitively from peripheral blood samples. At present, the PNA-NGS method is likely the most sensitive method to detect low-abundance GNAS mutation. 相似文献
998.
Atsushi Kimura Yuji Wada Tomohiro Masuda Sho-ichi Goto Daisuke Tsuzuki Haruo Hibino Dongsheng Cai Ippeita Dan 《PloS one》2013,8(7)
Background
When people are asked to adjust the color of familiar objects such as fruits until they appear achromatic, the subjective gray points of the objects are shifted away from the physical gray points in a direction opposite to the memory color (memory color effect). It is still unclear whether the discrepancy between memorized and actual colors of objects is dependent on the familiarity of the objects. Here, we conducted two experiments in order to examine the relationship between the degree of a subject’s familiarity with objects and the degree of the memory color effect by using logographs of food and beverage companies.Methods and Findings
In Experiment 1, we measured the memory color effects of logos which varied in terms of their familiarity (high, middle, or low). Results demonstrate that the memory color effect occurs only in the high-familiarity condition, but not in the middle- and low-familiarity conditions. Furthermore, there is a positive correlation between the memory color effect and the actual number of domestic stores of the brand. In Experiment 2, we assessed the semantic association between logos and food/beverage names by using a semantic priming task to elucidate whether the memory color effect of logos relates to consumer brand cognition, and found that the semantic associations between logos and food/beverage names in the high-familiarity brands were stronger than those in the low-familiarity brands only when the logos were colored correctly, but not when they were appropriately or inappropriately colored, or achromatic.Conclusion
The current results provide behavioral evidence of the relationship between the familiarity of objects and the memory color effect and suggest that the memory color effect increases with the familiarity of objects, albeit not constantly. 相似文献999.
Tomohiro Kotaki Siti Qamariyah Khairunisa Septhia Dwi Sukartiningrum M. Vitanata Arfijanto Takako Utsumi Irine Normalina Retno Handajani Prihartini Widiyanti Musofa Rusli Retno Pudji Rahayu Maria Inge Lusida Yoshitake Hayashi Nasronudin Masanori Kameoka 《PloS one》2013,8(12)
Background
Human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS) cause serious health problems and have an impact on the Indonesian economy. In addition, the rapid epidemic growth of HIV is continuing in Indonesia. Commercial sex plays a significant role in the spread of HIV; therefore, in order to reveal the current HIV prevalence rate among commercial sex workers (CSWs), we conducted an epidemiological study on HIV infection among CSWs residing in Surabaya, the capital of East Java province of Indonesia with large communities of CSWs.Methodology/Principal Findings
The prevalence of HIV infection among 200 CSWs was studied. In addition, the subtype of HIV type 1 (HIV-1) and the prevalence of other blood-borne viruses, hepatitis B virus (HBV), hepatitis C virus (HCV) and GB virus C (GBV-C), were studied. The prevalence rates of HIV, hepatitis B core antibody, hepatitis B surface antigen, anti-HCV antibodies and anti-GBV-C antibodies were 11%, 64%, 4%, 0.5% and 0% among CSWs involved in this study, respectively. HIV-1 CRF01_AE viral gene fragments were detected in most HIV-positive samples. In addition, most CSWs showed low awareness of sexually transmitted diseases and had unprotected sex with their clients.Conclusions/Significance
The HIV prevalence rate among CSWs was significantly higher than that among the general population in Indonesia (0.2–0.4%). In addition, CSWs were at a high risk of exposure to HBV, although chronic HBV infection was less frequently established. Our results suggest the necessity of efficient prevention programs for HIV and other blood-borne viral infections among CSWs in Surabaya, Indonesia. 相似文献1000.
Kinetic analyses of GroE-assisted folding provide a dynamic sequence of molecular events that underlie chaperonin function. We used stopped-flow analysis of various fluorescent GroEL mutants to obtain details regarding the sequence of events that transpire immediately after ATP binding to GroEL and GroEL with prebound unfolded proteins. Characterization of GroEL CP86, a circularly permuted GroEL with the polypeptide ends relocated to the vicinity of the ATP binding site, showed that GroES binding and protection of unfolded protein from solution is achieved surprisingly early in the functional cycle, and in spite of greatly reduced apical domain movement. Analysis of fluorescent GroEL SR-1 and GroEL D398A variants suggested that among other factors, the presence of two GroEL rings and a specific conformational rearrangement of Helix M in GroEL contribute significantly to the rapid release of unfolded protein from the GroEL apical domain. 相似文献