全文获取类型
收费全文 | 31341篇 |
免费 | 1497篇 |
国内免费 | 166篇 |
专业分类
耳鼻咽喉 | 372篇 |
儿科学 | 557篇 |
妇产科学 | 301篇 |
基础医学 | 4007篇 |
口腔科学 | 885篇 |
临床医学 | 2239篇 |
内科学 | 7680篇 |
皮肤病学 | 527篇 |
神经病学 | 2451篇 |
特种医学 | 1199篇 |
外科学 | 4991篇 |
综合类 | 199篇 |
预防医学 | 1162篇 |
眼科学 | 469篇 |
药学 | 2695篇 |
中国医学 | 67篇 |
肿瘤学 | 3203篇 |
出版年
2023年 | 154篇 |
2022年 | 303篇 |
2021年 | 544篇 |
2020年 | 254篇 |
2019年 | 387篇 |
2018年 | 502篇 |
2017年 | 409篇 |
2016年 | 482篇 |
2015年 | 517篇 |
2014年 | 689篇 |
2013年 | 871篇 |
2012年 | 1268篇 |
2011年 | 1366篇 |
2010年 | 788篇 |
2009年 | 687篇 |
2008年 | 1201篇 |
2007年 | 1252篇 |
2006年 | 1284篇 |
2005年 | 1389篇 |
2004年 | 1303篇 |
2003年 | 1279篇 |
2002年 | 1334篇 |
2001年 | 1222篇 |
2000年 | 1363篇 |
1999年 | 1187篇 |
1998年 | 405篇 |
1997年 | 302篇 |
1996年 | 307篇 |
1995年 | 264篇 |
1994年 | 253篇 |
1993年 | 246篇 |
1992年 | 800篇 |
1991年 | 717篇 |
1990年 | 731篇 |
1989年 | 776篇 |
1988年 | 708篇 |
1987年 | 637篇 |
1986年 | 608篇 |
1985年 | 570篇 |
1984年 | 442篇 |
1983年 | 331篇 |
1982年 | 188篇 |
1980年 | 159篇 |
1979年 | 284篇 |
1978年 | 222篇 |
1977年 | 172篇 |
1974年 | 165篇 |
1973年 | 152篇 |
1971年 | 153篇 |
1969年 | 171篇 |
排序方式: 共有10000条查询结果,搜索用时 23 毫秒
991.
The purpose of the present study was to investigate the electromyography (EMG) to torque relationship of the vastus intermedius
(VI) muscle. Thirteen healthy men performed maximal voluntary contraction (MVC) and submaximal contraction during isometric
knee extension at 10% of the MVC to 90% of the MVC at intervals of 10% of the MVC level. Surface EMG was detected from four
muscle components of the QF muscle group, i.e., VI, vastus lateralis (VL), vastus medialis, and rectus femoris (RF) muscles.
Normalized muscle activation in the VI muscle was significantly lower than in the VL muscle at a lower torque level (20 and
40% of MVC) and significantly lower compared to the RF muscle at a higher torque level (from 60 to 90% of MVC). These results
suggest that neuromuscular activation in the VI muscle is not consistent with the other components of QF muscle group during
submaximal knee extension contractions. 相似文献
992.
Saori Nagao Kazuaki Taguchi Hiromi Sakai Ryota Tanaka Hirohisa Horinouchi Hiroshi Watanabe Koichi Kobayashi Masaki Otagiri Toru Maruyama 《Biomaterials》2014
Carbon monoxide (CO) has potent anti-inflammatory and anti-oxidant effects. We report herein on the preparation of a nanotechnology-based CO donor, CO-bound hemoglobin-vesicles (CO-HbV). We hypothesized that CO-HbV could have a therapeutic effect on idiopathic pulmonary fibrosis (IPF), an incurable lung fibrosis, that is thought to involve inflammation and the production of reactive oxygen species (ROS). Pulmonary fibril formation and respiratory function were quantitatively evaluated by measuring hydroxyproline levels and forced vital capacity, respectively, using a bleomycin-induced pulmonary fibrosis mice model. CO-HbV suppressed the progression of pulmonary fibril formation and improved respiratory function compared to saline and HbV. The suppressive effect of CO-HbV on pulmonary fibrosis can be attributed to a decrease in ROS generation by inflammatory cells, NADPH oxidase 4 and the production of inflammatory cells, cytokines and transforming growth factor-β in the lung. This is the first demonstration of the inhibitory effect of CO-HbV on the progression of pulmonary fibrosis via the anti-oxidative and anti-inflammatory effects of CO in the bleomycin-induced pulmonary fibrosis mice model. CO-HbV has the potential for use in the treatment of, not only IPF, but also a variety of other ROS and inflammation-related disorders. 相似文献
993.
994.
Sachiko Konosu‐Fukaya Yasuhiro Nakamura Fumiyoshi Fujishima Atsuko Kasajima Keely M McNamara Yayoi Takahashi Kensuke Joh Hideo Saito Naomasa Ioritani Yoshihiro Ikeda Yoichi Arai Mika Watanabe Hironobu Sasano 《Pathology international》2014,64(3):133-141
Renal epithelioid angiomyolipoma (EAML) is a potentially malignant tumor type whose characteristics and biomarkers predictive of malignant behavior have not been elucidated. Here, we report three cases of renal EAML with malignant features but without histories of tuberous sclerosis complex. Case 1 involved a 29‐year‐old man with a 12‐cm solid mass in the right kidney who underwent radical right nephrectomy. Case 2 involved a 22‐year‐old woman with a retroperitoneal mass who underwent radical right nephrectomy and retroperitoneal tumorectomy. Local recurrence was detected 7 years post‐surgery. Case 3 involved a 23‐year‐old man with a 14‐cm solid mass in the left kidney who underwent radical left nephrectomy. Microscopically, the tumors in all cases demonstrated proliferation of epithelioid cells with atypia, mitotic activity, necrosis, hemorrhage, and vascular invasion. Epithelioid cells in all cases were immunohistochemically positive for melanocytic and myoid markers and weakly positive for E‐cadherin and β‐catenin. Immunohistochemistry revealed activation of the mammalian target of rapamycin pathway. Here, we report the morphological and immunohistochemical features of clinically or histologically malignant renal EAML. 相似文献
995.
Hiromi Kashiwazaki Masatoshi Kakizaki Yuzuru Ikehara Akira Togayachi Hisashi Narimatsu Rihito Watanabe 《Pathology international》2014,64(5):199-208
Carbohydrate structures, including Lewis X (Lex), which is not synthesized in mutant mice that lack α1,3‐fucosyltransferase 9 (Fut9?/?), are involved in cell–cell recognition and inflammation. However, immunological alteration in Fut9?/? mice has not been studied. Thus, the inflammatory response of Fut9?/? mice was examined using the highly neurovirulent mouse hepatitis virus (MHV) JHMV srr7 strain. Pathological study revealed that inflammation induced in the brains of Fut9?/? mice after infection was more extensive compared with that of wild‐type mice, although viral titers obtained from the brains of mutant mice were lower than those of wild‐type mice. Furthermore, the reduction in cell numbers in the spleens of wild‐type mice after infection was not observed in the infected Fut9?/? mice. Although there were no clear differences in the levels of cytokines examined in the brains between Fut9?/? and wild‐type mice except for interferon‐β (IFN‐β) expression, some of those in the spleens, including interferon‐γ (IFN‐γ), interleukin‐6 (IL‐6), and monocyte chemoattractant protein‐1 (MCP‐1), showed higher levels in Fut9?/? than in wild‐type mice. Furthermore, Fut9?/? mice were refractory to the in vivo inoculation of endotoxin (LPS) compared with wild‐type mice. These results indicate that Lex structures are involved in host responses against viral or bacterial challenges. 相似文献
996.
Seiko Nakajima Osamu Seguchi Yoshihiro Murata Tomoyuki Fujita Hiroki Hata Takafumi Yamane Michinari Hieda Takuya Watanabe Takuma Sato Haruki Sunami Masanobu Yanase Junjiro Kobayashi Takeshi Nakatani 《Journal of artificial organs》2014,17(2):197-201
Despite continual improvements in ventricular assist device (VAD) therapy, various clinical issues are emerging. Importantly, various types of thromboembolic complications have been reported to date. Recently, we encountered a rare continuous-flow VAD-related thromboembolic event that resulted in acute myocardial infarction. A 26-year-old female who just underwent HeartMate II® VAD implantation suddenly developed widespread anterolateral myocardial infarction on postoperative day 16. Echocardiography and aortography revealed a large thrombus on the left coronary cusp of the aortic valve that almost completely occluded the left coronary ostium. After VAD implantation, her aortic valve did not open, even at relatively low pump speeds; this was thought to be one of the causes for thrombus formation. Continuous suction of blood from the left ventricle and non-pulsatile flow into the ascending aorta resulted in a continuously closed aortic valve and stagnation of blood in the coronary cusp. Furthermore, both small body size (body surface area <1.3 m2) and postoperative right ventricular failure may have exacerbated blood stagnation and thrombus formation in this patient. We should have adjusted the anticoagulation and antiplatelet therapy protocols based on the patient’s condition. She underwent off-pump coronary artery bypass surgery and remained in clinically stable condition afterwards. 相似文献
997.
Satoru Muro Kumiko Yamaguchi Yasuo Nakajima Kentaro Watanabe Masayo Harada Akimoto Nimura Keiichi Akita 《Surgical and radiologic anatomy : SRA》2014,36(6):551-559
Purpose
The minute details of the structure of the anal canal are still not well understood. The complex structural configuration of the muscles, ligaments and raphes remains unclarified. This study was undertaken to determine the precise structure of the posterior part of the anal canal and to facilitate an understanding of previous studies.Methods
For macroscopic examination, 14 right pelvic halves from 14 Japanese cadavers were used. Observation and dissection were performed from the median plane. In the histological examination, six left pelvic halves were used. The sections of the posterior parts of the anal canal were stained with hematoxylin and eosin, Elastic van Gieson, anti-smooth actin antibody and anti-skeletal myosin antibody.Results
We identified the following muscles arranged from the internal side to the external side: internal anal sphincter, longitudinal muscle (LM), external anal sphincter (EAS) and levator ani muscle (LAM). Two different types of conformation of the posterior part of the anal canal were found, each bearing a different shape of EAS. In both types, LM penetrated the inferior part of EAS. After penetrating EAS, some fibers of LM ran posterosuperiorly and attached to the “the posterior fibers” which reach the dorsal side of the coccyx.Conclusions
We defined and labeled the connective tissues between the anal canal and coccyx on the basis of their relative position to LAM. Based on a comparison of the two types of the posterior part of the anal canal, we propose that there are two phases due to constriction and relaxation of LM. 相似文献998.
Masataka Sato Yuji Hiramatsu Shonosuke Matsushita Shoko Sato Yasunori Watanabe Yuzuru Sakakibara 《Journal of artificial organs》2014,17(3):265-271
Since bioprosthetic valve dysfunction may arise due to histological calcification in the crosslinking process by glutaraldehyde (GA), non-GA crosslinking reagents have been investigated. We compared the efficacy of triglycidylamine (TGA), a newly synthesized epoxy compound, and GA as crosslinking reagents for the treatment of autologous tissues. We assessed the strength of crosslinked tissues using shrinkage temperature (Ts) measured by differential scanning calorimetry. We also conducted subdermal allografting of the crosslinked pericardium and thoracic aorta in rats, and verified the anti-calcification efficacy of TGA by histological evaluations with von Kossa stain, and immunological evaluations using tenascin-C (TN-C) or matrix metalloproteinase-9 (MMP-9). TGA treatment resulted in slower increases in Ts of the pericardium, and it required 9–12 h to reach Ts achieved by GA. In subdermal implantation of rat tissues, calcium content was lower in the TGA group than in the GA groups (p < 0.005). The expression site of TN-C and MMP-9 differed from the primary location of calcium deposition in the thoracic aorta treated with TGA suggesting a different underlying mechanism in calcification between GA and TGA crosslinking. In conclusion, TGA crosslinking in the allograft showed superior anti-calcification effect as compared to brief treatment by GA, although TGA crosslinking process was slow. 相似文献
999.
Antifouling blood purification membrane composed of cellulose acetate and phospholipid polymer 总被引:7,自引:0,他引:7
The ideal surface of an artificial blood purification membrane needs hemocompatibility and durability of high performance; it should not adsorb any proteins or cells but should still have high permeability in the desired range of solute size. To improve the anti-fouling property of cellulose acetate (CA) membranes, a CA membrane blended with poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-co-n-butyl methacrylate (BMA)) (PMB30) was designed as a blood purification membrane. The polymer solutions for preparing the membrane were prepared using a solvent mixture composed of N, N-dimethylformamide, acetone, 2-propanol or water. The CA and CA/PMB30 blend membranes with an asymmetric and porous structure were prepared by a phase inversion process.The characteristics of the CA/PMB30 blend membrane, such as structural properties, mechanical properties, and solute permeability were examined with attention to changes in the preparation conditions of the membrane. The CA/PMB30 blend membrane had good water and solute permeability and a sharp molecular weight cut-off property. Moreover, the amount of proteins adsorbed on the CA/PMB30 blend membrane surface was less than that of the original CA membrane and a conventional polysulfone membrane. Adhesion and activation of platelets on the CA/PMB30 blend membrane were reduced compared with that on a CA membrane. In addition, the CA/PMB30 blend membrane showed good permselectivity and an antifouling property during a long time ultrafiltration experiment with protein solutions. 相似文献
1000.
Katagiri H Kawai Y Sugizaki N Sakai K Handa M Okamoto S Watanabe K 《Rinsho byori. The Japanese journal of clinical pathology》2003,51(6):516-521
Thrombotic thrombocytopenic purpura(TTP) is a multisystem disorders characterized by thrombocytopenia, microangiopathic hemolytic anemia associated with red cell fragmentation, and neurological and renal symptoms. Plasma of patients with TTP has been shown to contain unusually large von Willebrand factor(vWF) multimers that may cause platelet agglutination in vivo. Recently, a metalloprotease responsible for cleavage of vWF multimers has been isolated from normal human plasma and was found to be deficient in some patients with TTP. We examined the activity of the vWF-cleaving protease(vWF-CP), by modified Furlan's method, in plasma from patients with a familial TTP, 3 acquired TTP, 4 thrombotic microangiopathy(TMA) and 2 veno-occlusive disease(VOD) associated after allo-BMT. Diluted plasma samples of patients were incubated with protease-free vWF purified from normal human plasma, in the presence of urea and barium ions. The extent of vWF degradation was assayed by electrophoresis in SDS-agarose gels and immunoblotting. Activity of vWF-CP from 12 normal plasma have been shown as 77-180%(average 115%), whereas, no vWF-CP(below 5%) was observed in plasma from familial TTP, before and after plasma exchange, although FFP infusion therapy has been effective for this patient to recover thrombocytopenia. In 3 acquired TTP, 2 patients showed lack of vWF-CP activity in plasma, and inhibitors against vWF-CP have been elucidated by plasma cross-mixing test. After extensive plasma exchange and FFP infusion followed by corticosteroid therapy, normal vWF-CP was recovered in plasma from 2 acquired TTP patients. Among BMT patients, plasma from 4 BMT-TMA showed normal vWF-CP activities as 55-111%, whereas plasma from 2 BMT-VOD revealed low vWF-CP activity, as 24% and 37%, respectively. Thus, measurement of vWF-CP is crucial to predict differentiation of primary forms of TMA to establish the pathogenesis in varied endothelial dysfunction. 相似文献