全文获取类型
收费全文 | 43606篇 |
免费 | 2049篇 |
国内免费 | 375篇 |
专业分类
耳鼻咽喉 | 442篇 |
儿科学 | 954篇 |
妇产科学 | 488篇 |
基础医学 | 5805篇 |
口腔科学 | 725篇 |
临床医学 | 2612篇 |
内科学 | 11299篇 |
皮肤病学 | 1020篇 |
神经病学 | 3250篇 |
特种医学 | 1773篇 |
外科学 | 7560篇 |
综合类 | 176篇 |
一般理论 | 6篇 |
预防医学 | 1120篇 |
眼科学 | 1001篇 |
药学 | 2712篇 |
中国医学 | 170篇 |
肿瘤学 | 4917篇 |
出版年
2023年 | 242篇 |
2022年 | 496篇 |
2021年 | 882篇 |
2020年 | 468篇 |
2019年 | 653篇 |
2018年 | 911篇 |
2017年 | 691篇 |
2016年 | 883篇 |
2015年 | 965篇 |
2014年 | 1241篇 |
2013年 | 1581篇 |
2012年 | 2549篇 |
2011年 | 2845篇 |
2010年 | 1614篇 |
2009年 | 1484篇 |
2008年 | 2678篇 |
2007年 | 2901篇 |
2006年 | 2928篇 |
2005年 | 2936篇 |
2004年 | 3049篇 |
2003年 | 3092篇 |
2002年 | 3061篇 |
2001年 | 459篇 |
2000年 | 377篇 |
1999年 | 530篇 |
1998年 | 758篇 |
1997年 | 640篇 |
1996年 | 599篇 |
1995年 | 501篇 |
1994年 | 451篇 |
1993年 | 487篇 |
1992年 | 296篇 |
1991年 | 287篇 |
1990年 | 231篇 |
1989年 | 215篇 |
1988年 | 224篇 |
1987年 | 170篇 |
1986年 | 136篇 |
1985年 | 144篇 |
1984年 | 155篇 |
1983年 | 119篇 |
1982年 | 122篇 |
1981年 | 151篇 |
1980年 | 127篇 |
1979年 | 80篇 |
1978年 | 100篇 |
1977年 | 76篇 |
1976年 | 63篇 |
1975年 | 50篇 |
1974年 | 37篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Tsuyoshi Kitanishi Yoshinari Aimi Hiroya Kitano Mikio Suzuki Hiroshi Kimura Atsushi Saito Takeshi Shimizu Ikuo Tooyama 《ACTA HISTOCHEMICA ET CYTOCHEMICA》2013,46(5):145-152
We previously discovered a splice variant of choline acetyltransferase (ChAT) mRNA, and designated the variant protein pChAT because of its preferential expression in peripheral neuronal structures. In this study, we examined the immunohistochemical localization of pChAT in rat cochlea and compared the distribution pattern to those of common ChAT (cChAT) and acetylcholinesterase. Some neuronal cell bodies and fibers in the spiral ganglia showed immunoreactivity for pChAT, predominantly the small spiral ganglion cells, indicating outer hair cell type II neurons. In contrast, cChAT- and acetylcholinesterase-positive structures were localized to fibers and not apparent in ganglion cells. After ablation of the cochlear nuclei, many pChAT-positive cochlear nerve fibers became clearly visible, whereas fibers immunopositive for cChAT and acetylcholine esterase disappeared. These results suggested that pChAT and cChAT are localized in different systems of the rat cochlea; pChAT in the afferent and cChAT in the efferent structures. 相似文献
992.
Taketo Susa Nobuhiko Sawai Takeo Aoki Akiko Iizuka-Kogo Hiroshi Kogo Akihide Negishi Satoshi Yokoo Kuniaki Takata Toshiyuki Matsuzaki 《ACTA HISTOCHEMICA ET CYTOCHEMICA》2013,46(6):187-197
Aquaporins are water channel proteins which enable rapid water movement across the plasma membrane. Aquaporin-5 (AQP5) is the major aquaporin and is expressed on the apical membrane of salivary gland acinar cells. We examined the effects of repeated administration of pilocarpine, a clinically useful stimulant for salivary fluid secretion, and isoproterenol (IPR), a stimulant for salivary protein secretion, on the abundance of AQP5 protein in rat salivary glands by immunofluorescence microscopy and semi-quantitative immunoblotting. Unexpectedly AQP5 was decreased in pilocarpine-administered salivary glands, in which fluid secretion must be highly stimulated, implying that AQP5 might not be required for fluid secretion at least in pilocarpine-administered state. The abundance of AQP5, on the other hand, was found to be significantly increased in IPR-administered submandibular and parotid glands. To address the possible mechanism of the elevation of AQP5 abundance in IPR-administered animals, changes of AQP5 level in fasting animals, in which the exocytotic events are reduced, were examined. AQP5 was found to be decreased in fasting animals as expected. These results suggested that the elevation of cAMP and/or frequent exocytotic events could increase AQP5 protein. AQP5 expression seems to be easily changed by salivary stimulants, although these changes do not always reflect the ability in salivary fluid secretion. 相似文献
993.
994.
Azumi Ishizaki Kaori Matsushita Huyen Thi Thanh Hoang Dorothy M. Agdamag Cuong Hung Nguyen Vuong Thi Tran Toshiyuki Sasagawa Kunikazu Saikawa Raphael Lihana Hung Viet Pham Xiuqiong Bi Van Thanh Ta Thuc Van Pham Hiroshi Ichimura 《Journal of medical virology》2013,85(6):1069-1076
Human papillomavirus (HPV) has several intragenotypic variants with different geographical and ethnic distributions. This study aimed to elucidate the distribution patterns of E6 and E7 (E6/E7) intragenotypic variants of HPV type 16 (HPV‐16), which is most common worldwide, and HPV‐52, which is common in Asian countries such as Japan, the Philippines, and Vietnam. In previous studies, genomic DNA samples extracted from cervical swabs were collected from female sex workers in these three countries and found to be positive for HPV‐16 or HPV‐52. Samples were amplified further for their E6/E7 genes using type‐specific primers and analyzed genetically. Seventy‐nine HPV‐16 E6/E7 genes were analyzed successfully and grouped into three lineages: European (Prototype), European (Asian), and African‐2. The prevalences of HPV‐16 European (Prototype)/European (Asian) lineages were 19.4%/80.6% (n = 31) in Japan, 75.0%/20.8% (n = 24) in the Philippines, and 0%/95.8% (n = 24) in Vietnam. The 109 HPV‐52 E6/E7 genes analyzed successfully were grouped into four lineages, A–D; the prevalences of lineages A/B/C/D were, respectively, 5.1%/92.3%/0%/2.6% in Japan (n = 39), 34.4%/62.5%/0%/3.1% in the Philippines (n = 32), and 15.8%/73.7%/7.9%/2.6% in Vietnam (n = 38). The distribution patterns of HPV‐16 and HPV‐52 lineages in these countries differed significantly (P < 0.000001 and P = 0.0048, respectively). There was no significant relationship between abnormal cervical cytology and either HPV‐16 E6/E7 lineages or specific amino acid mutations, such as E6 D25E, E6 L83V, and E7 N29S. Analysis of HPV‐16 and HPV‐52 E6/E7 genes can be a useful molecular‐epidemiological tool to distinguish geographical diffusion routes of these HPV types in Asia. J. Med. Virol. 85: 1069–1076, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
995.
996.
Ryoichi Nakajima Hiroshi Kamada Taishu Kasai Yohei Tomaru Miki Waku Ayano Yamaki Atsuhiko Ban Shumpei Miyakawa Masashi Yamazaki Hitoshi Shiraki 《Journal of Rural Medicine》2021,16(3):154
Objective: In 2020, coronavirus disease-2019 (COVID-19) became the cause of a pandemic. In response, the Japan Sports Agency issued warnings about secondary damage to health, such as the threat to physical and mental well-being due to the lack of exercise in this situation. In this study, we report on cross-sectional and longitudinal examinations of standing trunk flexion to evaluate how temporary long-term school closures affected musculoskeletal function in elementary school students.Patients and Methods: All children in one public elementary school in T-city during the school years 2019 and 2020 were included in this study. A digital forward flexion meter was used to measure standing trunk flexion.Results: In this study, 284 (284/289: 98.3%) and 266 (266/274: 97.1%) children in school years 2020 and 2019, respectively, were found to have valid data for cross-sectional analysis. The standing trunk flexion did not show significant differences between grades or sexes. In the longitudinal analysis, the results of the comparison of standing trunk flexion in children for two consecutive years revealed significant differences only between grades 3 and 4 (P<0.05) and between girls in grades 3 and 4 (P<0.01), but no significant differences in other grades or among boys or girls were observed.Conclusion: Initially, we expected that there would be a difference in the results of functional assessment using standing trunk flexion depending on the period of absence from school. However, the results of this study showed no significant changes in standing trunk flexion. Moreover, since children’s musculoskeletal functions may be affected by various factors during the COVID-19 pandemic, they should be carefully monitored in the future. 相似文献
997.
Yoko Uchida Fujiya Gomi Shigeo Murayama Hiroshi Takahashi 《The American journal of pathology》2013,182(5):1718-1726
998.
Junki Maruyama Masatoshi Okamatsu Kosuke Soda Yoshihiro Sakoda Hiroshi Kida 《Archives of virology》2013,158(12):2473-2478
Highly pathogenic avian influenza viruses have poly-basic amino acid sequences at the cleavage site in their hemagglutinin (HA). Although this poly-basic region is a prerequisite factor for pathogenicity in chickens, not much is known about additional factors responsible for the acquisition of pathogenicity of the duck influenza virus in chickens. Here, we introduced multiple basic amino acid residues into the HA cleavage site of the A/duck/Hokkaido/Vac-2/2004 (H7N7) strain of avian influenza virus, which has low pathogenicity in chickens; the resultant Vac2sub-P0 strain was not intravenously pathogenic in chickens. In contrast, the Vac2sub-P3 strain, which was recovered from three consecutive passages of Vac2sub-P0 in chicks, was intravenously pathogenic in chickens. Six amino acid substitutions were identified by comparison of the Vac2sub-P3 and Vac2sub-P0 genomic sequences: Lys123Glu in PB2, Asn16Asp in PB1, Glu227Gly and Ile388Thr in HA, Gly228Arg in M1, and Leu46Pro in M2. The results of intravenous inoculations of chickens with recombinant virus indicated that all six amino acid substitutions were required to varying degrees for Vac2sub-P3 pathogenicity, with Glu227Gly and Ile388Thr in HA being particularly essential. These results reveal the roles of additional viral factors in the acquisition of pathogenicity in addition to the previously characterized role of the poly-basic amino acid sequences at the HA cleavage site. 相似文献
999.
Azusa Maruyama Shoichi Tokumoto Hiroshi Yamaguchi Yusuke Ishida Tsukasa Tanaka Kazumi Tomioka Masahiro Nishiyama Kyoko Fujita Daisaku Toyoshima Hiroaki Nagase 《Brain & development》2021,43(4):548-555
IntroductionChildren with either febrile seizure or acute encephalopathy exhibit seizures and/or impaired consciousness accompanied by fever of unknown etiology (SICF). Among children with SICF, we previously reported those who have refractory status epilepticus or prolonged neurological abnormalities with normal AST levels are at a high risk for the development of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), considered to be caused by excitotoxicity. Non-convulsive seizures (NCS) are common in critically ill children and cause excitotoxic neuronal injury. The aim of this study was to elucidate the prevalence of NCS in the acute phase of children at a high risk for developing AESD and the relationship between NCS in the acute phase and neurological outcomes.MethodsWe studied 137 children with SICF at a high risk for developing AESD and who underwent continuous electroencephalogram monitoring (cEEG) upon admission to a tertiary pediatric care center at Hyogo Prefectural Kobe Children’s Hospital between October 2007 and August 2018. Patient characteristics and outcomes were compared between patients with NCS and without NCS.ResultsOf the 137 children, NCS occurred in 30 children; the first NCS were detected in cEEG at the beginning in 63.3%, during the first hour in 90%, and within 12 h in 96.7%. Neurological sequelae were more common in NCS patients (20.0%) than in non-NCS patients (1.9%; p = 0.001). Five in 30 NCS patients (16.7%) and 3 in 107 non-NCS patients (2.8%) developed AESD (p = 0.013).ConclusionThe occurrence of NCS is associated with subsequent neurological sequelae, especially the development of AESD. 相似文献
1000.
Shinji Okano Hidetaka Yamamoto Shinji Kono Hiroshi Fujii Ken Shirabe Yoshihiko Maehara Yoshinao Oda 《Pathology, research and practice》2013
Atypical lipomatous tumor or well-differentiated liposarcoma/dedifferentiated liposarcoma (DDLPS) is the most frequent subtype of malignant adipocytic tumor. This tumor typically presents in late adult life, most commonly in the retroperitoneum, extremities, or spermatic cord. It has been reported that the dedifferentiated component consists mainly of high-grade sarcoma, including undifferentiated pleomorphic sarcoma, fibrosarcoma, and myxofibrosarcoma, and it has been recently reported that the dedifferentiated component can be also made up of a low-grade sarcomatous component. Therefore, the dedifferentiated areas exhibit a wide morphological spectrum that commonly includes fibroblastic/myofibroblastic and fibrohistiocytic tumors but very rarely includes vascular tumors. We present here the first reported case of DDLPS with a hemangioendothelioma-like component in the spermatic cord. 相似文献