全文获取类型
收费全文 | 9497篇 |
免费 | 494篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 114篇 |
儿科学 | 200篇 |
妇产科学 | 172篇 |
基础医学 | 1241篇 |
口腔科学 | 202篇 |
临床医学 | 577篇 |
内科学 | 2544篇 |
皮肤病学 | 175篇 |
神经病学 | 762篇 |
特种医学 | 379篇 |
外科学 | 1634篇 |
综合类 | 49篇 |
预防医学 | 285篇 |
眼科学 | 229篇 |
药学 | 516篇 |
中国医学 | 6篇 |
肿瘤学 | 961篇 |
出版年
2023年 | 68篇 |
2022年 | 120篇 |
2021年 | 194篇 |
2020年 | 94篇 |
2019年 | 176篇 |
2018年 | 209篇 |
2017年 | 177篇 |
2016年 | 191篇 |
2015年 | 191篇 |
2014年 | 285篇 |
2013年 | 312篇 |
2012年 | 514篇 |
2011年 | 516篇 |
2010年 | 262篇 |
2009年 | 267篇 |
2008年 | 490篇 |
2007年 | 528篇 |
2006年 | 438篇 |
2005年 | 457篇 |
2004年 | 452篇 |
2003年 | 426篇 |
2002年 | 438篇 |
2001年 | 283篇 |
2000年 | 322篇 |
1999年 | 234篇 |
1998年 | 104篇 |
1997年 | 98篇 |
1996年 | 73篇 |
1995年 | 76篇 |
1994年 | 69篇 |
1993年 | 53篇 |
1992年 | 183篇 |
1991年 | 157篇 |
1990年 | 159篇 |
1989年 | 145篇 |
1988年 | 136篇 |
1987年 | 149篇 |
1986年 | 139篇 |
1985年 | 134篇 |
1984年 | 81篇 |
1983年 | 67篇 |
1982年 | 51篇 |
1979年 | 63篇 |
1978年 | 41篇 |
1977年 | 30篇 |
1974年 | 47篇 |
1973年 | 29篇 |
1972年 | 38篇 |
1971年 | 29篇 |
1969年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Hidenori Kanazawa Kenichi Utano Shigeyoshi Kijima Takahiro Sasaki Yasuyuki Miyakura Hisanaga Horie Yoshikazu Nakamura Hideharu Sugimoto 《Japanese journal of radiology》2014,32(5):274-281
Objectives
The purpose of this study was to compare the degree of colorectal distention between manual insufflation using room air and automatic insufflation using carbon dioxide for computed tomography colonography performed as a preoperative examination for patients with colon cancer.Materials and methods
Participants comprised 200 patients who underwent computed tomography colonography immediately after colonoscopy from October 2011–2012. The first 100 patients were examined using manual insufflation, and the remaining 100 patients were examined using automated insufflation. Two radiologists independently assessed colorectal distention using a 4-point scale in six segments: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum. Mean scores of the two radiologists were used to analyze whether any differences existed between techniques in terms of the degree of distention per segment.Results
Mean distention values for the colonic lumen were better using the automated technique than with the manual technique in both positions (p < 0.05). In segments, distention was significantly better using the automated technique than using the manual technique in the sigmoid and descending colon for prone patients, and in all segments for supine patients.Conclusions
Automated carbon dioxide insufflation offered significantly improved colorectal distention scores compared to manual room air insufflation. 相似文献83.
Repetitive transcranial magnetic stimulation for protection against delayed neuronal death induced by transient ischemia 总被引:18,自引:0,他引:18
OBJECT: Data in the present study demonstrate that repetitive transcranial magnetic stimulation (rTMS) induces ischemic tolerance against delayed neuronal death (DND) of hippocampal neurons following an otherwise lethal ischemic insult. METHODS: Various regimens of rTMS were delivered to adult gerbils at various times prior to an episode of ischemia induced by transient (5-minute) bilateral common carotid artery (CCA) occlusion. The extent of DND in the CA1 region of the hippocampus was assessed quantitatively 7 days after the transient ischemic episode. When rTMS was delivered 2 to 5 days prior to bilateral CCA occlusion, DND was substantially attenuated; delivery of rTMS 12 to 24 hours prior to occlusion induced partial tolerance. In the group of animals that had received stimulation 2 days prior to occlusion, neuron density in the CA1 sector was significantly higher (three gerbils, 210.33, 86.01% of normal) than in the group that experienced ischemia only (three gerbils, 10.66, 4.36% of normal). A similar degree of neuron sparing occurred when stimulation was delivered 3, 4, or 5 days prior to occlusion. Note that rTMS was effective when it was delivered at frequencies of 25 and 50 Hz. Stimulation at 25 Hz for 128 seconds (3200 pulses) was more effective than stimulation at 50 Hz for 64 seconds (3200 pulses) or 128 seconds (6400 pulses), however. CONCLUSIONS: Noninvasive rTMS represents an important tool for exploring the mechanisms of ischemic tolerance and preventing ischemic neuronal damage. 相似文献
84.
Yinghan Zhu Hironori Nakatani Walid Yassin Norihide Maikusa Naohiro Okada Akira Kunimatsu Osamu Abe Hitoshi Kuwabara Hidenori Yamasue Kiyoto Kasai Kazuo Okanoya Shinsuke Koike 《Schizophrenia bulletin》2022,48(3):563
Background and HypothesisMachine learning approaches using structural magnetic resonance imaging (MRI) can be informative for disease classification; however, their applicability to earlier clinical stages of psychosis and other disease spectra is unknown. We evaluated whether a model differentiating patients with chronic schizophrenia (ChSZ) from healthy controls (HCs) could be applied to earlier clinical stages such as first-episode psychosis (FEP), ultra-high risk for psychosis (UHR), and autism spectrum disorders (ASDs).Study DesignTotal 359 T1-weighted MRI scans, including 154 individuals with schizophrenia spectrum (UHR, n = 37; FEP, n = 24; and ChSZ, n = 93), 64 with ASD, and 141 HCs, were obtained using three acquisition protocols. Of these, data regarding ChSZ (n = 75) and HC (n = 101) from two protocols were used to build a classifier (training dataset). The remainder was used to evaluate the classifier (test, independent confirmatory, and independent group datasets). Scanner and protocol effects were diminished using ComBat.Study ResultsThe accuracy of the classifier for the test and independent confirmatory datasets were 75% and 76%, respectively. The bilateral pallidum and inferior frontal gyrus pars triangularis strongly contributed to classifying ChSZ. Schizophrenia spectrum individuals were more likely to be classified as ChSZ compared to ASD (classification rate to ChSZ: UHR, 41%; FEP, 54%; ChSZ, 70%; ASD, 19%; HC, 21%).ConclusionWe built a classifier from multiple protocol structural brain images applicable to independent samples from different clinical stages and spectra. The predictive information of the classifier could be useful for applying neuroimaging techniques to clinical differential diagnosis and predicting disease onset earlier. 相似文献
85.
A virtual reality‐based method of decreasing transmission time of visual feedback for a tele‐operative robotic catheter operating system 下载免费PDF全文
86.
Naoko Iwahashi Kondo Ken Shirabe Yohei Mano Akinobu Taketomi Tomoharu Yoshizumi Toru Ikegami Toshiro Masuda Hiroto Kayashima Naotaka Hashimoto Kazutoyo Morita Mizue Matsuo Yoshihiko Maehara 《Surgery today》2012,42(12):1210-1214
The outcome after surgical resection for intrahepatic cholangiocarcinoma has not been satisfactorily evaluated due to its malignant behavior. Surgical resection, however, has the potential to improve the prognosis and may allow surgeons to experience rare cases with long survival. This report presents the case of a patient who developed recurrence 9?years after resection of intrahepatic cholangiocarcinoma. A 76-year-old female was diagnosed to have intrahepatic cholangiocarcinoma and underwent an extended right posterior subsegmentectomy. The gross appearance showed a mass-forming type tumor. The histopathological examination revealed well to moderately differentiated adenocarcinoma associated with portal vein invasion. Subcutaneous metastasis in the head as the first sign of relapse was diagnosed 9?years after hepatectomy. The histopathological findings of the subcutaneous tumor were similar to those of the intrahepatic cholangiocarcinoma, thus suggesting metastasis from intrahepatic cholangiocarcinoma. Positron emission tomography with 2-[fluorine-18]-fluoro-2-deoxy-d-glucose was useful for detecting multiple metastases. Long-term follow-up for more than 5?years is recommended because the present case shows that late recurrence of intrahepatic cholangiocarcinoma occurs even 5?years after resection. 相似文献
87.
Ayuko Yamashita Mineaki Kitamura Yohei Tateishi Kenta Torigoe Kumiko Muta Yasushi Mochizuki Tsuyoshi Izumo Takayuki Matsuo Akira Tsujino Hideki Sakai Hiroshi Mukae Tomoya Nishino 《Internal medicine (Tokyo, Japan)》2022,61(8):1133
Objective The quality of life and activities of daily living (ADL) are generally poor among dialysis patients after intracerebral hemorrhaging, and their precise clinical course remains unclear. In addition, the association between the severity of cerebral hemorrhaging and the long-term prognosis in these patients has not been fully elucidated. This study aimed to evaluate the subsequent prognosis of hemodialysis patients who survived the acute phase of intracerebral hemorrhaging. Methods We included hemodialysis patients who were admitted to Nagasaki University Hospital between 2007 and 2015 for intracerebral hemorrhaging treatment. After excluding cases of in-hospital death, survivors were classified using the 5-point modified Rankin Scale (mRS), which specifically measures the ADL in patients with cerebrovascular diseases. The patients were followed up at the medical facilities to which they were transferred in the same medical zone until 2017. Results Out of 91 patients with cerebral hemorrhaging (65±11 years old, 66% men, hemodialysis duration 108±91 months), 62 survived until discharge. Twenty-one patients died during observation, largely due to infectious diseases, such as sepsis and pneumonia (n=16, 76%). Compared to patients with mRS 0-4 (n=31), those with mRS 5 (n=31) showed a significantly poorer prognosis. The hazard ratio adjusted for age and antiplatelets was 13.7 (95% confidence interval: 3.88-63.7, p<0.001). Conclusion Hemodialysis patients with intracerebral hemorrhaging who were bedridden showed poor outcomes. The major causes of death were infections. Therefore, these patients should be carefully monitored for infections in order to improve their prognosis. 相似文献
88.
89.
Tereza Cristina Cardoso Camila Silva-Frade Cilene Vidovix Táparo Lucas Hidenori Okamura Eduardo Furtado Flores 《Molecular and cellular probes》2013,27(5-6):237-242
The objective of this study was to optimize an internal control to improve SYBR-Green-based qPCR to amplify/detect the BoHV-5 US9 gene in bovine embryos produced in vitro and experimentally exposed to the virus. We designed an SYBR-Green-based binding assay that is quick to perform, reliable, easily optimized and compares well with the published assay. Herein we demonstrated its general applicability to detect BoHV-5 US9 gene in bovine embryos produced in vitro experimentally exposed to BoHV-5. In order to validate the assay, three different reference genes were tested; and the histone 2a gene was shown to be the most adequate for normalizing the qPCR reaction, by considering melting and standard curves (p < 0.05). On the other hand, no differences were found in the development of bovine embryos in vitro whether they were exposed to BoHV-5 reference and field strains comparing to unexposed embryos. The developed qPCR assay may have important field applications as it provides an accurate BoHV-5 US9 gene detection using a proven reference gene and is considerably less expensive than the TaqMan qPCR currently employed in sanitary programs. 相似文献
90.
Fabiana Miraglia Minekazo Matsuo Zenaide Maria Morais Odir Antonio Dellagostin Fabiana Kömmling Seixas Julio César Freitas Rudy Hartskeerl Luisa Zanolli Moreno Bárbara Letícia Costa Gisele Oliveira Souza Silvio Arruda Vasconcellos Andrea Micke Moreno 《Diagnostic microbiology and infectious disease》2013
Leptospira interrogans serogroup Icterohaemorrhagiae is the major serogroup infecting humans worldwide, and rodents and dogs are the most significant transmission sources in urban environments. Knowledge of the prevalent serovars and their maintenance hosts is essential to understand the epidemiology of leptospirosis. In this study, 20 Leptospira isolates were evaluated by pulsed-field gel electrophoresis (PFGE), variable number tandem-repeat analysis (VNTR), serotyping, and determination of antimicrobial resistance profile. Isolates, originated from bovine, canine, human, and rodent sources, were characterized by microscopic agglutination test with polyclonal and monoclonal antibodies and were identified as L. interrogans serogroup Icterohaemorrhagiae serovar Copenhageni. MICs of antimicrobials often used in veterinary medicine were determined by broth microdilution test. Most of tested antibiotics were effective against isolates, including penicillin, ampicillin, and ceftiofur. Higher MIC variability was observed for fluoroquinolones and neomycin; all isolates were resistant to trimethoprim/sulfamethoxazole and sulphadimethoxine. Isolates were genotyped by PFGE and VNTR; both techniques were unable to discriminate between serovars Copenhageni and Icterohaemorrhagiae, as expected. PFGE clustered all isolates in 1 pulsotype, indicating that these serovars can be transmitted between species and that bovine, rodent, and dogs can maintain them in the environment endangering the human population. 相似文献