全文获取类型
收费全文 | 4910篇 |
免费 | 295篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 36篇 |
儿科学 | 118篇 |
妇产科学 | 66篇 |
基础医学 | 752篇 |
口腔科学 | 76篇 |
临床医学 | 331篇 |
内科学 | 1288篇 |
皮肤病学 | 256篇 |
神经病学 | 332篇 |
特种医学 | 104篇 |
外科学 | 460篇 |
综合类 | 21篇 |
一般理论 | 1篇 |
预防医学 | 263篇 |
眼科学 | 147篇 |
药学 | 367篇 |
中国医学 | 14篇 |
肿瘤学 | 593篇 |
出版年
2024年 | 5篇 |
2023年 | 29篇 |
2022年 | 91篇 |
2021年 | 156篇 |
2020年 | 103篇 |
2019年 | 97篇 |
2018年 | 161篇 |
2017年 | 123篇 |
2016年 | 148篇 |
2015年 | 116篇 |
2014年 | 170篇 |
2013年 | 242篇 |
2012年 | 344篇 |
2011年 | 366篇 |
2010年 | 198篇 |
2009年 | 197篇 |
2008年 | 343篇 |
2007年 | 360篇 |
2006年 | 336篇 |
2005年 | 317篇 |
2004年 | 319篇 |
2003年 | 283篇 |
2002年 | 275篇 |
2001年 | 42篇 |
2000年 | 29篇 |
1999年 | 41篇 |
1998年 | 53篇 |
1997年 | 51篇 |
1996年 | 33篇 |
1995年 | 27篇 |
1994年 | 20篇 |
1993年 | 26篇 |
1992年 | 14篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 16篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1972年 | 13篇 |
1971年 | 3篇 |
1969年 | 3篇 |
排序方式: 共有5225条查询结果,搜索用时 11 毫秒
11.
Arpp,a new homolog of carp,is preferentially expressed in type 1 skeletal muscle fibers and is markedly induced by denervation 总被引:3,自引:0,他引:3
Tsukamoto Y Senda T Nakano T Nakada C Hida T Ishiguro N Kondo G Baba T Sato K Osaki M Mori S Ito H Moriyama M 《Laboratory investigation; a journal of technical methods and pathology》2002,82(5):645-655
In this study, we isolated and characterized a murine counterpart of the human Arpp (hArpp) gene. Sequence analysis revealed that the murine Arpp (mArpp) gene is almost identical to the Ankrd2 gene, which has recently been isolated as a mouse gene induced in stretched skeletal muscle. The mArpp gene encodes a protein of 332 amino acids that contains four well-conserved ankyrin-repeat domains in the central portion of the protein. The amino acid sequence of mArpp protein (mArpp) is highly homologous to that of mouse cardiac-restricted ankyrin-repeat protein (Carp), which is proposed to be a putative genetic marker for cardiac hypertrophy. Immunohistochemical analysis revealed that mArpp is preferentially expressed in type 1 skeletal muscle fibers, and that mArpp is localized in both the nucleus and the sarcomeric I-band of muscle fibers, suggesting that Arpp may function as a nuclear and sarcomeric protein. Furthermore, mArpp was also expressed in neurons of the cerebellum and cerebrum, the islets of Langerhans in the pancreas, and the esophageal epithelium, suggesting that mArpp may play a functional physiologic role in brain, pancreas, and esophagus as well as in type 1 muscle fibers. Interestingly, although mArpp was localized in both nucleus and cytoplasm in neurons, its localization was restricted to nucleus in pancreas and esophagus, suggesting that intracellular localization of mArpp is regulated in a tissue-specific manner. Furthermore, we found that mArpp- and Carp-expression in skeletal muscle were markedly up-regulated after denervation. Although the elevated expression level of Carp was kept only for two weeks after denervation, that of Arpp was kept at least for 4 weeks, suggesting that mArpp and Carp may play distinct functional roles in denervated skeletal muscle. 相似文献
12.
The dopamine agonist cabergoline provides neuroprotection by activation of the glutathione system and scavenging free radicals 总被引:4,自引:0,他引:4
Yoshioka M Tanaka Ki Miyazaki I Fujita N Higashi Y Asanuma M Ogawa N 《Neuroscience research》2002,43(3):259-267
Free radicals are involved in the pathogenesis and/or progression of Parkinson's disease (PD). Several ergot derivative dopamine (DA) agonists have been reported to scavenge free radicals in vitro and to show a neuroprotective effect in vivo. We investigated the in vitro free radical scavenging and antioxidant activities of cabergoline, a long-acting ergot DA agonist, as well as its ability to activate glutathione (GSH), catalase (Cat) and superoxide dismutase (SOD) activating effects and its in vivo neuroprotective properties against 6-hydroxydopamine (6-OHDA) intracerebroventricularly (i.c.v.) in mice. The striatal DA turnover induced by i.c.v. injection of 6-OHDA was completely normalized by pretreatment with cabergoline. Moreover, cabergoline scavenged free radicals in vitro and significantly reduced lipid peroxidation in vitro and in vivo. Furthermore, daily administration of cabergoline to mice significantly increased striatal GSH levels by activation of RNA expressions of GSH-related enzymes, although striatal Cat and SOD activities did not change. In addition, our present results suggest that repeated administration of cabergoline attenuates both 6-OHDA-induced nigrostriatal DAergic dysfunction and DA neuronal cell death, since cabergoline also had a neuroprotective effect in the immunohistochemical experiment. In conclusion, our findings indicate that the multiple antioxidant mechanisms of cabergoline, such as activation of the GSH system and the direct free radical scavenging activity, may explain the neuroprotective effect of this ergot DA agonist. 相似文献
13.
Three phases of neurogenesis can be recognized during Xenopus spinal cord development. An early peak during gastrulation/neurulation is followed by a phase of low level neurogenesis throughout the remaining embryonic stages and a later peak at early larval stages. We show here that several genes known to be essential for early neurogenesis (X-NGNR-1, XNeuroD, XMyT1, X-Delta-1) are also expressed during later phases of neurogenesis in the spinal cord, suggesting that they are involved in regulating spinal neurogenesis at later stages. However, additional neuronal determination genes may be important during larval stages, because X-NGNR-1 shows only scant expression in the spinal cord during larval stages. Thyroid hormone treatment of early larvae promotes neurogenesis in the spinal cord, where thyroid hormone receptor xTRalpha is expressed from early larval stages onward and results in precocious up-regulation of XNeuroD, XMyT1, and N-Tubulin expression. Similarly, thyroid hormone treatments of Xenopus embryos, which were coinjected with xTRalpha and the retinoid X receptor xRXRalpha, repeatedly resulted in increased numbers of neurons, whereas unliganded receptors repressed neurogenesis. Our findings show that thyroid hormones are sufficient to up-regulate neurogenesis in the Xenopus spinal cord. 相似文献
14.
We compared morphological and morphometric data on various motor neurons in the human pyramidal system using the modified Klüver-Barrera staining method with extremely minimized shrinkage ratio and an image-analyzer. We classified motor neurons in the human pyramidal system into three groups according to the measurement data. This report may be of interest to better understand the process of nerve conduction in the human pyramidal system. 相似文献
15.
We evaluated the effects of the erbium:YAG laser (2.9 m wavelength) on ocular structures. Energy was successfully transmitted through a fiberoptic bundle for intraocular and extraocular applications. The wavelength was strongly absorbed by ocular tissues, producing ablations with minimal thermal damage. Our results indicated that the erbium: YAG laser may have potential uses as a photoablative tool to reshape the corneal surface and as a surgical knife. 相似文献
16.
17.
Kayoko Minakata Osamu Suzuki Takeshi Kumazawa Minoru Asano Naoko Harada 《International journal of legal medicine》1990,103(8):599-607
Summary An electron spin resonance (ESR) method already in use for the quantitative analysis of paraquat was applied to the analysis of diquat in blood, serum, urine, tissue homogenates and several drinks without purification of the samples. The diquat radical produced with ascorbic acid at alkaline pH was much more stable than that produced with the commonly used sodium dithionite. Radical decay in solutions covered with n-hexane was less than 5% after 60 min over a wide range of ascorbic acid concentrations. In 0.2N NaOH solution 85% of the radicals was present even after 24h. The limit of detection was 0.3 g/ml and the required amount of sample was 0.1 ml. When both diquat and paraquat were present in a sample the diquat was first extracted with 1-butanol prior to the ESR measurement, because both species were converted to the radicals. 相似文献
18.
K Katsurada 《Brain and nerve》1983,35(9):927-934
The criteria of brain death established by Japanese Society of EEG in 1974, necessitates a prerequisite; be applicable only to "acute destructive, primary gross lesion of brain". Namely, because of insufficient clinical data, secondary brain lesion such as post-anoxia, intoxication, metabolic coma and some kinds of CNS infection were excluded for the object to determine brain death. The criteria published by others also describe that etiology of coma should be clarified, and that careful measures are necessary to diagnose brain death if the cause of coma is unknown. In the present study, it was investigated that whether a clinico-pathological entity of brain death could exist universally regardless of the etiology, and by what means it could be defined clinically. The patients suffering from nondestructive, secondary brain lesions and who showed "brain death-like state" were selected for the study. ("Brain death-like state" requires coma, dilated nonreactive pupis and arrest of respiration concomitantly for more than 6 hours.) And 25 patients were collected, whose underlying diseases were post-anoxia or shock, CO intoxication, Paraquat poisoning, near-drowning or suffocation, hepatic coma, accidental hypothermia and sepsis, with or without the episode of cardiac arrest. Though all the patients died from 1 to 13 days after the insult, clinical signs of brain death-like state were not always irreversible. Isoelectric EEG was obtained on that state in 11 patients and repeated EEG revealed no return on those patients. But another 5 patients showed EEG activity when brain death was strongly suspected clinically.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
19.
Taro Semba Yasuhiro Funahashi Naoto Ono Yuji Yamamoto Naoko Hata Sugi Makoto Asada Kentaro Yoshimatsu Toshiaki Wakabayashi 《Clinical cancer research》2004,10(4):1430-1438
We reported previously that an angiogenesis inhibitor, E7820, inhibits in vitro tube formation of human umbilical vein endothelial cell through the suppression of integrin alpha2 expression. Here we describe the antiangiogenic and antitumor effects of E7820 in mice and discuss the feasibility of using platelet integrin alpha2 expression on platelets as a biological marker of the efficacy of E7820. Oral administration of E7820 significantly inhibited basic fibroblast growth factor-induced angiogenesis in Matrigel implants and human colon WiDr tumor-induced angiogenesis in a dorsal air sac model. Twice-daily treatment with E7820 clearly inhibited the s.c. tumor growth of seven tumor cell lines derived from human colon, breast, pancreas, and kidney, and completely suppressed the growth of human pancreatic KP-1 and human colon LoVo cell lines. Moreover, E7820 significantly inhibited the growth of KP-1 and human colon tumor Colo320DM cells orthotopically implanted in the pancreas and cecum, respectively. The efficacy of E7820 was comparable in the s.c. and orthotopic transplantation models. Immunohistochemical analyses using anti-CD31 antibody showed that E7820 significantly reduced microvessel density in orthotopically implanted KP-1 tumor. E7820 reduced integrin alpha2 expression on a megakaryocytic cell line, Dami cells, induced by phorbol 12-myristate 13-acetate treatment. It also decreased the expression level of integrin alpha2 on platelets withdrawn from mice bearing s.c. KP-1 tumor at a dosage close to that affording antitumor activity. These data demonstrate that E7820 showed a broad-spectrum antitumor effect in mice through inhibition of angiogenesis and indicate that the decrease of integrin alpha2 on platelets might serve as a biological marker for the antitumor efficacy of E7820. 相似文献
20.
Shin-ichi Fukumoto Naoko Yamauchi Hisashi Moriguchi Yoshitaka Hippo Akira Watanabe Junji Shibahara Hirokazu Taniguchi Shumpei Ishikawa Hirotaka Ito Shogo Yamamoto Hiroko Iwanari Mitsugu Hironaka Yuichi Ishikawa Toshiro Niki Yasunori Sohara Tatsuhiko Kodama Masaharu Nishimura Masashi Fukayama Hirotoshi Dosaka-Akita Hiroyuki Aburatani 《Clinical cancer research》2005,11(5):1776-1785
PURPOSE: Squamous cell carcinoma (SCC) and adenocarcinoma of the lung are currently subject to similar treatment regimens despite distinct differences in histology and epidemiology. The aim of this study is to identify a molecular target with diagnostic and therapeutic values for SCC. EXPERIMENTAL DESIGN: Genes specifically up-regulated in SCC were explored through microarray analysis of 5 SCCs, 5 adenocarcinomas, 10 small cell lung carcinomas, 27 normal tissues, and 40 cancer cell lines. Clinical usefulness of these genes was subsequently examined mainly by immunohistochemical analysis. RESULTS: Seven genes, including aldo-keto reductase family 1, member B10 (AKR1B10), were identified as SCC-specific genes. AKR1B10 was further examined by immunohistochemical analysis of 101 non-small cell lung carcinomas (NSCLC) and its overexpression was observed in 27 of 32 (84.4%) SCCs and 19 of 65 (29.2%) adenocarcinomas. Multiple regression analysis showed that smoking was an independent variable responsible for AKR1B10 overexpression in NSCLCs (P < 0.01) and adenocarcinomas (P < 0.01). AKR1B10 staining was occasionally observed even in squamous metaplasia, a precancerous lesion of SCC. CONCLUSION: AKR1B10 was overexpressed in most cases with SCC, which is closely associated with smoking, and many adenocarcinoma cases of smokers. These results suggest that AKR1B10 is a potential diagnostic marker specific to smokers' NSCLCs and might be involved in tobacco-related carcinogenesis. 相似文献