全文获取类型
收费全文 | 7353篇 |
免费 | 348篇 |
国内免费 | 80篇 |
专业分类
耳鼻咽喉 | 63篇 |
儿科学 | 129篇 |
妇产科学 | 86篇 |
基础医学 | 933篇 |
口腔科学 | 149篇 |
临床医学 | 440篇 |
内科学 | 2177篇 |
皮肤病学 | 142篇 |
神经病学 | 520篇 |
特种医学 | 203篇 |
外科学 | 1013篇 |
综合类 | 50篇 |
预防医学 | 241篇 |
眼科学 | 108篇 |
药学 | 528篇 |
中国医学 | 9篇 |
肿瘤学 | 990篇 |
出版年
2023年 | 34篇 |
2022年 | 83篇 |
2021年 | 162篇 |
2020年 | 105篇 |
2019年 | 128篇 |
2018年 | 201篇 |
2017年 | 150篇 |
2016年 | 150篇 |
2015年 | 183篇 |
2014年 | 250篇 |
2013年 | 317篇 |
2012年 | 491篇 |
2011年 | 565篇 |
2010年 | 304篇 |
2009年 | 246篇 |
2008年 | 441篇 |
2007年 | 513篇 |
2006年 | 483篇 |
2005年 | 448篇 |
2004年 | 464篇 |
2003年 | 436篇 |
2002年 | 482篇 |
2001年 | 77篇 |
2000年 | 54篇 |
1999年 | 90篇 |
1998年 | 103篇 |
1997年 | 76篇 |
1996年 | 87篇 |
1995年 | 86篇 |
1994年 | 68篇 |
1993年 | 65篇 |
1992年 | 55篇 |
1991年 | 40篇 |
1990年 | 35篇 |
1989年 | 39篇 |
1988年 | 30篇 |
1987年 | 30篇 |
1986年 | 25篇 |
1985年 | 25篇 |
1984年 | 23篇 |
1983年 | 20篇 |
1982年 | 15篇 |
1981年 | 18篇 |
1980年 | 18篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1975年 | 7篇 |
1965年 | 4篇 |
排序方式: 共有7781条查询结果,搜索用时 15 毫秒
101.
Kiyokazu Takebayashi Yoshimoto Sekine Nori Takei Yoshio Minabe Haruo Isoda Hiroyasu Takeda Katsuhiko Nishimura Kazuhiko Nakamura Katsuaki Suzuki Yasuhide Iwata Harumi Sakahara Norio Mori 《Neuropsychopharmacology》2004,29(5):1019-1026
Long-term toluene abuse causes a variety of psychiatric symptoms. However, little is known about abnormalities at the neurochemical level in the living human brain after long-term exposure to toluene. To detect neurochemical changes in the basal ganglia of subjects with a history of long-term toluene use, proton magnetic resonance spectroscopy (1H MRS) was performed in 12 abstinent toluene users and 13 healthy comparisons with no history of drug abuse. N-acetylaspartate (NAA), creatine plus phosphocreatine (Cr + PCr), choline-containing compounds (Cho), and myo-inositol (MI) levels were measured in the left and right basal ganglia. The Cho/Cr + PCr ratio, a marker of membrane metabolism, was significantly increased in the basal ganglia of toluene users in comparison to that of the control subjects. Furthermore, the increase in the Cho/Cr + PCr ratio was significantly correlated with the severity of residual psychiatric symptoms. These findings suggest that long-term toluene use causes membrane disturbance in the basal ganglia, which is associated with residual psychiatric symptoms that persist even after long-term abstinence from toluene use. 相似文献
102.
Kohei Fukuoka Atsushi Sasaki Takaaki Yanagisawa Tomonari Suzuki Kenji Wakiya Jun-ichi Adachi Kazuhiko Mishima Takamitsu Fujimaki Masao Matsutani Ryo Nishikawa 《Brain tumor pathology》2012,29(4):229-234
We report a case of pineal parenchymal tumor (PPT) in an 11-year-old girl. Brain magnetic resonance imaging (MRI) revealed a large tumor (48?mm) located in the pineal region with heterogeneous enhancement after gadolinium administration. The patient underwent tumor removal with craniotomy; only partial tumor resection could be performed because of massive intratumoral bleeding. Histopathological examination of the tumor showed lobular proliferation of round cells with moderate atypia. Cellularity varied by area, and focal Homer Wright rosettes were identified. Examination of tumor cells revealed a few mitoses (two mitotic figures per 10 high-powered fields), and immunohistochemical staining revealed positivity for synaptophysin, slight positivity for neurofilament protein (NFP) with antibody clone 2F11, and strong positivity for NFP with clone NF-M+H. The pathological diagnosis was pineal parenchymal tumor of intermediate differentiation grade II according to World Health Organization criteria despite a high (22%) MIB-1 labeling index (LI). The patient had a favorable clinical course after an intensified chemotherapy regimen designed for pineoblastoma and radiotherapy administered to the entire neuraxis, followed by stereotactic radiotherapy. In conclusion, MIB-1 LI could be a useful tool for deciding therapeutic strategies for PPT treatment when there is a discrepancy between clinical findings and pathological grading. 相似文献
103.
Shigeki Kushida Masayuki Matsumura Hiroko Tanaka Yoshihiro Ami Mitsuo Hori Mikirou Kobayashi Kazuhiko Uchida Ken-ichi Yagami Tsuneo Kameyama Toshihiro Yoshizawa Hidehiro Mizusawa Yuzo Iwasaki Masanao Miwa 《Cancer science》1993,84(8):831-833
We intravenously injected Ra-1 cells or MT-2 cells into female adult WKA rats. Spastic paraparesis mainly in the hind-limbs was observed in 1 out of 2 Ra-1 cell-injected WKA rats and in 3 out of 8 MT-2 cell-injected WKA rats 20 27 months after injection. The main neuropathological finding was symmetrical white matter degeneration with mononuclear cell infiltration of the spinal cord, similar to that of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients, and degeneration of nerve roots and peripheral nerves. Antibodies against HTLV-1 antigens were detected in plasma and cerebrospinal fluid from these HAM/TSP-like rats. HTLV-1 provirus was detected from the peripheral blood mononuclear cells of one of these rats 20 months after injection. Interestingly, spastic paraparesis was not observed in F344 rats. 相似文献
104.
Takayuki Muraoka Junichi Soh Shinichi Toyooka Keisuke Aoe Nobukazu Fujimoto Shinsuke Hashida Yuho Maki Norimitsu Tanaka Kazuhiko Shien Masashi Furukawa Hiromasa Yamamoto Hiroaki Asano Kazunori Tsukuda Takumi Kishimoto Takemi Otsuki Shinichiro Miyoshi 《Lung cancer (Amsterdam, Netherlands)》2013
Objectives
Malignant pleural mesothelioma (MPM) is an aggressive tumor with a poor prognosis. microRNA-34b/c (miR-34b/c), which plays an important role in the pathogenesis of MPM, is frequently downregulated by DNA methylation in approximately 90% of MPM cases. In this study, we estimated the degree of miR-34b/c methylation in serum-circulating DNA using a digital methylation specific PCR assay (MSP).Materials and methods
A real-time MSP assay was performed using the SYBR Green method. The melting temperature (Tm) of each PCR product was examined using a melting curve analysis. For a digital MSP assay, 40 wells were analyzed per sample. A total of 110 serum samples from 48 MPM cases, 21 benign asbestos pleurisy (BAP) cases, and 41 healthy volunteers (HVs) were examined.Results
Positive range of Tm value for miR-34b/c methylation was defined as 77.71–78.79 °C which was the mean ± 3 standard deviations of 40 wells of a positive control. The number of miR-34b/c methylated wells was counted per sample according to this criterion. The number of miR-34b/c methylated wells in MPM cases was significantly higher than that in BAP cases (P = 0.03) or HVs (P < 0.001). Advanced MPM cases tended to have higher number of miR-34b/c methylated wells than early MPM cases. Receiver–operating characteristic (ROC) curve analysis revealed that three number of miR-34b/c methylated wells per sample was the best cut-off of positivity of MPM with a 67% of sensitivity and a 77% specificity for prediction. The area under the ROC curve was 0.77.Conclusions
Our digital MSP assay can quantify miR-34b/c methylation in serum-circulating DNA. The degree of miR-34b/c methylation in serum-circulating DNA is associated with MPM, suggesting that this approach might be useful for the establishment of a new detection system for MPM. 相似文献105.
Hiroyuki Kohara Masahiro Tabata Katsuyuki Kiura Hiroshi Ueoka Kazuhiko Kawata Masakazu Chikamori Keisuke Aoe Kenichi Chikamori Akio Matsushita Mine Harada 《Clinical cancer research》2002,8(1):287-292
7-ethyl-10-[4-(1-piperidyl)-1-piperidyl] carbonyloxy-camptothecin, a topoisomerase I (topo I) inhibitor, is one of the most active agent against lung cancer, and its radiosensitizing effect has been reported recently. We evaluated a combination in vitro effect of irradiation and 7-ethyl-10-hydroxy-CPT (SN-38), an active metabolite of 7-ethyl-10-[4- (1-piperidyl)-1-piperidyl] carbonyloxy-camptothecin, on a human small cell lung cancer cell line (SBC-3) and its cisplatin-resistant subline (SBC-3/CDDP). Growth-inhibitory effects of irradiation with or without SN-38 were determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. A modified isobologram method was used to evaluate the treatment interaction. The combination of irradiation and SN-38 showed a synergistic inhibitory effect on the growth of SBC-3/CDDP despite its cross-resistance to irradiation and SN-38. In contrast, the same combination showed only an additive effect on the growth of parental SBC-3 cells. There was no significant difference in topo I protein expression between these two cell lines. In SBC-3 cells, topo I catalytic activity was suppressed by 4 Gy of irradiation, without a decrease of nuclear topo I protein, whereas the exposure of SBC-3 cells to 1 microM SN-38 subsequent to irradiation showed no remarkable additional effects on both topo I activity and protein content. On the other hand, in SBC-3/CDDP cells, topo I activity was unchanged by irradiation, but the subsequent exposure to SN-38 gave rise to a decrease in topo I activity, which was accompanied by a significant decrease in the topo I protein content (P = 0.02). These observations may indicate that SN-38 induces sequestration of topo I onto DNA in radiation-treated SBC-3/CDDP cells and suggest that the synergistic effect of irradiation and SN-38 in SBC-3/CDDP cells was considered attributable to DNA repair-related enhanced recruitment of topo I onto the damaged DNA. 相似文献
106.
Mao Akagawa Tatsuya Shirai Mitsuru Sada Norika Nagasawa Mayumi Kondo Makoto Takeda Koo Nagasawa Ryusuke Kimura Kaori Okayama Yuriko Hayashi Toshiyuki Sugai Takeshi Tsugawa Haruyuki Ishii Hisashi Kawashima Kazuhiko Katayama Akihide Ryo Hirokazu Kimura 《Viruses》2022,14(11)
Molecular interactions between respiratory syncytial virus (RSV) fusion protein (F protein) and the cellular receptor Toll-like receptor 4 (TLR4) and myeloid differentiation factor-2 (MD-2) protein complex are unknown. Thus, to reveal the detailed molecular interactions between them, in silico analyses were performed using various bioinformatics techniques. The present simulation data showed that the neutralizing antibody (NT-Ab) binding sites in both prefusion and postfusion proteins at sites II and IV were involved in the interactions between them and the TLR4 molecule. Moreover, the binding affinity between postfusion proteins and the TLR4/MD-2 complex was higher than that between prefusion proteins and the TLR4/MD-2 complex. This increased binding affinity due to conformational changes in the F protein may be able to form syncytium in RSV-infected cells. These results may contribute to better understand the infectivity and pathogenicity (syncytium formation) of RSV. 相似文献
107.
脂蛋白脂酶活化剂NO-1886抑制糖尿病兔动脉粥样硬化的形成 总被引:3,自引:2,他引:3
目的 合成化合物NO 1886 ,一种脂蛋白脂酶活化观察脂蛋白脂酶活化剂是否降低高脂 /高蔗糖饲料诱发的糖尿病新西兰兔的血浆葡萄糖并减轻其动脉粥样硬化。方法 给予高脂 /高蔗糖饲料升高新西兰兔血浆总胆固醇 ,甘油三酯和葡萄糖及降低高密度脂蛋白胆固醇而导致动脉粥样硬化。饲料中加入 1 0 %NO 1886进行治疗观察。分别在 0、4、8、12、16、2 0及 2 4wk从禁食过夜的兔耳静脉抽取血样测定葡萄糖和脂质水平。第 2 4周末 ,处死动物 ,分离主动脉 ,经苏丹Ⅳ染色固定脂质后 ,计算脂纹病变面积。结果 应用NO 1886后 ,实验动物血浆葡萄糖 ,总胆固醇和甘油三酯降低 ,高密度脂蛋白胆固醇增加。对动脉粥样硬化的发展具有抑制作用。结论 NO 1886不仅可改善脂质紊乱 ,而且可降低血浆葡萄糖 ,减轻糖尿病兔动脉粥样硬化 相似文献
108.
Naofumi Ikeda Toshihide Hayashi Shikou Gen Nobuhiko Joki Kazuhiko Aramaki 《Renal failure》2022,44(1):1098
PurposeTo determine the location of coronary atherosclerosis distribution observed in patients with chronic kidney disease (CKD).MethodsA cross-sectional study was conducted using the database of cardiovascular medicine data from Saitama Sekishinkai Hospital to clarify the association between renal function and angiographic characteristics of coronary atherosclerosis. In total, 3268 patients who underwent percutaneous coronary intervention were included. Propensity score matching revised the total to 1772. The association of renal function with the location and/or distribution of coronary atherosclerosis lesions was then examined.ResultsOverall, coronary lesion was observed in the left anterior descending coronary artery (LAD) in 56% patients, whereas 28% and 22% were in the right coronary artery (RCA) and left circumflex coronary artery (LCX), respectively. LAD was most affected and observed in 57% patients with stage 1 CKD. RCA was second-most affected, at 26% CKD stage 1, but it increased to 31%, 38%, and 59% in CKD 3, 4, and 5, respectively. In CKD 5 patients, the RCA was the most affected artery (59%), with 41% LAD lesions. Logistic regression analysis after propensity score matching showed that the odds ratios for an RCA lesion was 3.658 in CKD 5 (p = .025) compared with CKD 1 after adjusting for traditional risk factors.ConclusionThe prevalence of RCA lesions, but not LAD or LCX lesions, increased with increasing CKD stage. The pathophysiology of coronary atherosclerosis may differ by lesion location. Deterioration of renal function may affect progression of atherosclerosis more in the RCA than in the LAD or LCX. 相似文献
109.
Hisato Shima Toshio Doi Takuya Okamoto Yusuke Higashiguchi Megumi Harada Tomoko Inoue Manabu Tashiro Seiichiro Wariishi Norimichi Takamatsu Kazuhiko Kawahara Kazuyoshi Okada Jun Minakuchi 《Internal medicine (Tokyo, Japan)》2022,61(12):1863
A 39-year-old woman was hospitalized for nephrotic syndrome. Laboratory test results showed increased serum creatinine levels and urinary excretions of beta-2-microglobulin, and N-acetyl-beta-D-glucosaminidase. A renal biopsy revealed collapsing focal segmental glomerulosclerosis (FSGS) and acute interstitial nephritis. Despite treatment with pulse steroid followed by oral high-dose glucocorticoids and cyclosporines, heavy proteinuria persisted. After low-density lipoprotein apheresis (LDL-A) therapy was initiated, her proteinuria gradually decreased, leading to complete remission. A repeat renal biopsy after treatment revealed no collapsing glomeruli. Immediate LDL-A should be performed to treat cases of collapsing FSGS poorly responding to other treatments. 相似文献
110.
牛奶及其制品与乳腺癌关系的研究进展 总被引:2,自引:0,他引:2
乳腺癌是西方女性最常见的肿瘤,我国女性乳腺癌患者也逐年上升。和所有的肿瘤一样,乳腺癌的病因复杂多样,其中包括饮食因素。众多考察乳腺癌的流行病学研究提及奶及其制品的影响,但没能得出一致的结论。著名的美国护士健康研究也没有发现奶和奶制品摄入与乳腺癌发生有明显关系。汇总观察这些流行病学资料发现,奶酪能微弱地增加患乳腺癌的危险。动物研究表明,现代牛奶中富含的雌激素和胰岛素样生长因子(IGF)-I有明显的促进二甲基苯并蒽(DMBA)诱导的大鼠乳腺肿瘤的生长。系统介绍流行病学研究和实验室研究的最新成果,同时讨论牛奶中存在的可能影响乳腺癌发生的诸多成分,其中起促进作用的有饱和脂肪、各类激素和污染物,起保护作用的有钙、维生素D和一些脂肪酸。 相似文献