全文获取类型
收费全文 | 5059篇 |
免费 | 275篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 131篇 |
儿科学 | 153篇 |
妇产科学 | 107篇 |
基础医学 | 643篇 |
口腔科学 | 229篇 |
临床医学 | 306篇 |
内科学 | 1140篇 |
皮肤病学 | 236篇 |
神经病学 | 392篇 |
特种医学 | 121篇 |
外科学 | 642篇 |
综合类 | 14篇 |
预防医学 | 234篇 |
眼科学 | 94篇 |
药学 | 360篇 |
中国医学 | 13篇 |
肿瘤学 | 546篇 |
出版年
2024年 | 9篇 |
2023年 | 45篇 |
2022年 | 72篇 |
2021年 | 154篇 |
2020年 | 82篇 |
2019年 | 119篇 |
2018年 | 143篇 |
2017年 | 103篇 |
2016年 | 117篇 |
2015年 | 141篇 |
2014年 | 187篇 |
2013年 | 195篇 |
2012年 | 351篇 |
2011年 | 371篇 |
2010年 | 199篇 |
2009年 | 173篇 |
2008年 | 300篇 |
2007年 | 291篇 |
2006年 | 275篇 |
2005年 | 287篇 |
2004年 | 336篇 |
2003年 | 280篇 |
2002年 | 246篇 |
2001年 | 94篇 |
2000年 | 97篇 |
1999年 | 77篇 |
1998年 | 44篇 |
1997年 | 40篇 |
1996年 | 37篇 |
1995年 | 33篇 |
1994年 | 17篇 |
1993年 | 21篇 |
1992年 | 40篇 |
1991年 | 45篇 |
1990年 | 60篇 |
1989年 | 35篇 |
1988年 | 35篇 |
1987年 | 32篇 |
1986年 | 35篇 |
1985年 | 30篇 |
1984年 | 14篇 |
1983年 | 13篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 4篇 |
1973年 | 6篇 |
1972年 | 5篇 |
排序方式: 共有5361条查询结果,搜索用时 15 毫秒
41.
Yukiko Matsuura Naoko Kawata Noriyuki Yanagawa Toshihiko Sugiura Yoriko Sakurai Misuzu Sato Ken Iesato Jiro Terada Seiichiro Sakao Yuji Tada Nobuhiro Tanabe Yoichi Suzuki Koichiro Tatsumi 《European journal of radiology》2013
Objectives
Structural and functional changes in pulmonary vessels are prevalent at the initial stages of chronic obstructive pulmonary disease (COPD). These vascular alterations can be assessed using cross-sectional area (CSA) of small pulmonary vessels. However, neither in non-COPD smokers nor in COPD patients it has been defined whether the structural changes of pulmonary vessels detected by paired inspiratory and expiratory CT scans are associated with emphysematous changes. We quantified the CSA and low attenuation area (LAA) and evaluated the changes in these parameters in the inspiratory and expiratory phases.Materials and methods
Fifty consecutive non-COPD smokers and COPD patients were subjected to multi detector-row CT and the percentage of vessels with a CSA less than 5 mm2 as well as the percentage LAA for total lung area (%CSA < 5, %LAA, respectively) were calculated.Results
The %CSA < 5 correlated negatively with %LAA. The %CSA < 5 was lower in COPD patients with emphysema as compared with non-COPD smokers and COPD patients with or without mild emphysema. In addition, the %CSA < 5 was lower in the no/mild emphysema subgroup as compared with non-COPD smokers. The respiratory phase change of %CSA < 5 in COPD patients was greater than that in non-COPD smokers.Conclusion
The percentage of small pulmonary vessels decreased as emphysematous changes increase, and this decrease was observed even in patients with no/mild emphysema. Furthermore, respiratory phase changes in CSA were higher in COPD patients than in non-COPD smokers. 相似文献42.
Mai Kim Tetsuya Higuchi Yukiko Arisaka Arifudin Achmad Azusa Tokue Hideyuki Tominaga Go Miyashita Hidetaka Miyazaki Akihide Negishi Satoshi Yokoo Yoshito Tsushima 《Annals of nuclear medicine》2013,27(5):423-430
Objective
L-3-[18F]-fluoro-α-methyl tyrosine (18F-FAMT) is an amino acid tracer for positron emission tomography/computed tomography (PET/CT) which specifically transported into cancer cells by L-type amino acid transporter 1 (LAT1). LAT1 overexpression in tumors is significantly correlated with cell proliferation and angiogenesis. 18F-FAMT PET/CT, fluorine-18-fluorodeoxyglucose (18F-FDG) PET/CT and magnetic resonance imaging (MRI) were compared for their diagnostic performance in the detection of bone marrow invasion in patients with oral squamous cell carcinoma (OSCC).Methods
Twenty-seven patients with OSCC on the upper or lower alveolar ridge underwent staging by MRI, 18F-FDG PET/CT and 18F-FAMT PET/CT studies before surgery. Post-surgical pathologic examination was used as the standard to determine the final diagnoses. The possibility of bone marrow invasion on MRI, 18F-FDG PET/CT and 18F-FAMT PET/CT were usually graded retrospectively into five-point score. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated according to the obtained scores.Results
As the sensitivity of 18F-FDG PET/CT was highest (100 %) among that of MRI (95 %) and 18F-FAMT PET/CT (90 %), the specificity of 18F-FAMT PET/CT was highest (85.7 %) among that of MRI (57 %) and 18F-FDG PET/CT (14.3 %). The size of pathological tumor was accorded with that detected by 18F-FAMT PET/CT and was smaller than that detected by 18F-FDG PET/CT (P < 0.01). Significant difference was not found between 18F-FAMT PET tumor volume and pathological tumor volume.Conclusions
18F-FAMT PET/CT was useful and more specific than MRI or 18F-FDG PET/CT in the detection of bone marrow invasion of OSCC and may contribute to minimize the extent of resection in oral surgery patient. 相似文献43.
Yukiko Nakazono Kenji Tsujikawa Kenji Kuwayama Tatsuyuki Kanamori Yuko T. Iwata Kazuna Miyamoto Fumiyo Kasuya Hiroyuki Inoue 《Forensic Toxicology》2013,31(2):241-250
In recent years, a large number of clandestinely produced controlled-substance analogs (designer drugs) of amphetamine with high structural variety have been detected in forensic samples. Analytical differentiation of regioisomers is a significant issue in forensic drug analysis because, in most cases, legal controls are placed only on one or two of the three isomers. In this study, we used gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) for the differentiation of regioisomers of fluoroamphetamine analogs (fluoroamphetamines and fluoromethamphetamines), which were synthesized in our laboratories. Free bases and their acylated and silylated derivatives were subjected to GC–MS analysis using DB-1ms, DB-5ms, and DB-17ms capillary columns. The separation of free bases was incomplete on all columns. Trifluoroacetyl derivatives of 3- and 4-positional isomers showed slight separation on DB-1ms and DB-5ms. On the other hand, trimethylsilyl derivatization enabled baseline separation of six fluoroamphetamine analogs on DB-1ms and DB-5ms columns, which was sufficient for unequivocal identification. For LC–MS/MS, a pentafluorophenyl column was able to separate six regioisomeric fluoroamphetamine analogs but a conventional C18 column could not achieve separation between 3- and 4-positional isomers. These results show that a suitable choice of derivatization and analytical columns allows the differentiation of regioisomeric fluoroamphetamine analogs. 相似文献
44.
Yukiko Kanetsuna Yutaka Yamaguchi Hiroshi Toma Kazunari Tanabe 《Clinical transplantation》2003,17(S10):25-29
Abstract: We histologically evaluated protocol biopsy specimens of renal allografts obtained in the early period and 1 year after transplantation. The patients were divided into those with at least one history of acute rejection (AR group) and no history of rejection (NAR group), and the histopathological features in the two groups were compared. A total of 45 early protocol biopsy specimens were obtained from 40 patients, and 31 1-year biopsy specimens were obtained from 30 patients. Acute rejection (AR) or borderline change was observed in the early protocol biopsy specimens from 19 (45.2%) cases. AR or borderline change was observed in 12 of 19 (63.2%) in the AR group, and in 7/26 cases (26.9%) in the NAR group. The incidence of AR or borderline change in the AR group was higher than in the NAR group. Toxic tubulopathy was found in the early protocol biopsy in 16 cases (35.6%). The 1-year biopsies tended to reveal more complicated findings. Chronic rejection (CR) was seen in 8/16 cases (50.0%) in the AR group, and it was more frequent than NAR group (two cases, 13.3%). In conclusion, the incidences of both AR and CR were higher in the cases with a previous episode of AR. The early protocol biopsy was useful in screening for subclinical AR and toxic tubulopathy. The 1-year biopsy was useful for evaluating various types of chronic graft damage. We expect that adequate treatment based on protocol biopsy findings in each patient will lead to better graft survival. 相似文献
45.
Hayashida M Nishimoto Y Matsuura T Takahashi Y Kohashi K Souzaki R Taguchi T 《Journal of pediatric surgery》2007,42(12):2097-2101
Background
Biliary atresia (BA) is a cholestatic disease of unknown etiology. It has recently been suggested that graft-vs-host disease caused by microchimerism is an etiology in the development of autoimmune disease. Moreover, the liver is a frequent target organ of graft-vs-host disease. The aim of this study is to identify the presence and extent of maternal microchimerism and to determine whether it plays a role in the etiology of BA.Methods
The liver biopsy specimens of 6 male patients with BA (BA group) and 6 males with other liver diseases (non-BA group) were assayed for X- and Y-chromosome using fluorescent in situ hybridization. The cells with 2 sex chromosomes in the nuclei were counted. Cells with 1 X- and 1 Y-chromosomes were considered to be host cells, and those with 2 X-chromosome were considered to be of maternal origin.Results
The frequency of cells with XX chromosomes per 1000 host cells in the BA group and the non-BA group were 3.00 ± 0.75 and 0.99 ± 0.50, respectively (P = .005). Moreover, the age at the time of biopsy did not affect the number of chimeric cells.Conclusion
The presence of female cells in the liver of male patients with BA was significantly higher than in males with other liver disease. Maternal microchimerism is therefore suggested to contribute to the pathogenesis of BA. 相似文献46.
Yukiko Kaizu Sakae Ohkawa Hiromichi Kumagai 《Nephrology, dialysis, transplantation》2002,17(3):442-448
BACKGROUND: Measurement of muscle mass is useful for evaluating protein nutritional status. Various methods for estimating muscle mass in haemodialysis patients have recently been developed. METHODS: The validity of the estimate of creatinine production calculated with the creatinine kinetic model (CKM) was examined in 46 haemodialysis patients by comparing it with the actual creatinine production, this being determined from the sum of creatinine appearing in the dialysate and the estimated metabolic degradation. The correlation of various other muscle mass indices with creatinine production was also investigated in these patients. RESULTS: The estimate of creatinine production using CKM was significantly correlated with creatinine production calculated from the spent dialysate plus an estimate for the extra-renal creatinine degradation (r=0.90, P<0.001). A Bland-Altman analysis revealed that the mean prediction error for the estimate of creatinine production by CKM was +0.10 g/day and the limits of agreement were +0.34 to -0.14 g/day. The cross-sectional area of the thigh muscle measured by computed tomography (CT) was also significantly correlated with creatinine production (r=-0.86, P<0.01). In contrast, the correlations of 3-methylhistidine production measured in the spent dialysate, the mid-upper arm muscle circumference and the skeletal muscle mass estimated by an anthropometric prediction model with creatinine production were lower (r<0.82). CONCLUSION: Creatinine production calculated using CKM and CT measurement of thigh muscle area are valid methods for estimating muscle mass during routine clinical examinations of haemodialysis patients. 相似文献
47.
Miyakoshi S Kami M Tanimoto T Yamaguchi T Narimatsu H Kusumi E Matsumura T Takagi S Kato D Kishi Y Murashige N Yuji K Uchida N Masuoka K Wake A Taniguchi S 《Transplantation》2007,84(3):316-322
BACKGROUND: Myeloablative cord blood transplantation (CBT) for adult patients offers a 90% chance of engraftment with a 50% rate of transplant-related mortality, mostly attributable to infection. We have demonstrated the feasibility of reduced-intensity CBT (RI-CBT) for adult patients, in which cyclosporine was used for acute graft-versus-host disease (GVHD) prophylaxis. Transplantation-related mortality (TRM) was 27% within 100 days. Therefore our objective was to evaluate the feasibility of RI-CBT with tacrolimus as GVHD prophylaxis for adult patients with hematologic malignancies. METHODS: Thirty-four patients with a median age of 56.5 years (range; 22-68) with hematologic diseases underwent RI-CBT at Toranomon Hospital between November 2003 and September 2004. Preparative regimen comprised fludarabine 25 mg/m2 on days -7 to -3, melphalan 80 mg/m2 on day -2, and 4 Gy total body irradiation on day -1. GVHD prophylaxis was continuous intravenous infusion of tacrolimus 0.03 mg/kg, starting on day -1. RESULTS: Thirty-one patients achieved neutrophil engraftment at a median of day 20. Median infused total cell dose was 2.4 x 10E7/kg (range; 1.6-4.8). Thirty-two patients achieved complete donor chimerism at day 60. Grade II-IV acute GVHD occurred in 45% of patients, with a median onset of day 26. Primary disease recurred in five patients, and TRM within 100 days was 12%. Estimated 1-year overall survival was 70%. CONCLUSION: This study demonstrated the possible improvement in transplant-related mortality by tacrolimus as GVHD prophylaxis in adult RI-CBT recipients. 相似文献
48.
Kenichi Suga Shuji Kondo Sato Matsuura Yukiko Kinoshita Etsuko Kitano Michiyo Hatanaka Hajime Kitamura Yoshihiko Hidaka Takashi Oda Shoji Kagami 《Pediatric nephrology (Berlin, Germany)》2010,25(8):1547-1550
A 14-year-old girl presented with acute glomerulonephritis. Tests revealed hypocomplementemia and elevated Antistreptolysin-O
titers, and renal biopsy revealed endocapillary and mesangial proliferative glomerulonephritis with double contours of the
glomerular basement membrane (GBM). Despite methylprednisolone pulse therapy and the administration of oral prednisolone,
overt proteinuria and hypocomplementemia persisted. A second renal biopsy 6 months later confirmed the initial diagnosis of
dense deposit disease (DDD) based on electron-dense deposits in the GBM. C3 nephritic factor (C3NeF) and a deficiency of complement
factor H (CFH) were not evident. A nephritis-associated plasmin receptor (NAPlr), nephritogenic group A streptococcal antigen,
and the plasmin activity by in situ zymography were been in both the first and second biopsy specimens. The patient received
combined immunomodulatory therapy with prednisolone and mizoribine, and the urinary protein decreased to a mild level at 27 months
after disease onset. These findings suggest that persistent glomerular NAPlr deposition may be associated with the pathogenesis
of DDD in some patients without the involvement of C3NeF or CFH mutation and that DDD patients of this type may respond to
immunomodulatory treatment. 相似文献
49.
Shigeru Yamamoto MD Noriko Maeda MD Michiko Tamesa MD Yukiko Nagashima MD Kazuyoshi Suga MD Masaaki Oka MD 《The breast journal》2010,16(1):4-8
Abstract: Ultrasonography (US) is one tool for preoperative diagnosis of lymph node metastases in breast cancer. However, US cannot detect true sentinel lymph nodes (SLNs). We identified SLNs in 60 clinically node‐negative breast cancer patients using a real‐time virtual sonography (RVS) system to display in real time a virtual multi‐planar reconstruction obtained from computed tomography (CT) volume data corresponding to the same cross‐sectional image from US. CT volume data were obtained from our original three‐dimensional CT lymphography (3DCT‐LG), which accurately detects SLNs in breast cancer. SLN metastases were assessed by shape and visibility of the hilum. All patients underwent SLN biopsy and SLN metastases were examined pathologically. In all 60 patients, we were able to detect the same SLNs visualized by 3DCT‐LG. Suspicious SLN metastases were identified in seven of the 60 patients, and four of seven patients were pathologically positive. Positive predictive value was 57%. The remaining 53 patients displayed non‐suspect SLNs in which absence of metastasis from the SLN was confirmed histologically. Overall accuracy was 95%. This is a first attempt at preoperatively identifying SLNs using US guided by the RVS system in breast cancer patients. Although evaluation of SLN metastases was unsatisfactory, this method may be useful for preoperative fine‐needle aspiration cytology for diagnosis of SLN metastases. 相似文献
50.
Laparoscopic and endoscopic cooperative surgery for gastrointestinal stromal tumor dissection 总被引:1,自引:1,他引:1
Hiki N Yamamoto Y Fukunaga T Yamaguchi T Nunobe S Tokunaga M Miki A Ohyama S Seto Y 《Surgical endoscopy》2008,22(7):1729-1735
BACKGROUND: Laparoscopic wedge resections are increasingly applied for gastric submucosal tumors such as gastrointestinal stromal tumor (GIST). Despite this, no defined strategy exists to guide the surgeon in choosing the appropriate laparoscopic technique for an individual case on the basis of tumor characteristics such as location or size. This study aimed to introduce a laparoscopic and endoscopic cooperative surgery (LECS) for gastric wedge resection that is applicable for submucosal tumor resection independent of tumor location and size. METHODS: Seven patients underwent LECS for the resection of gastric submucosal tumors. Both mucosal and submucosal layers around the tumor were circumferentially dissected using endoscopic submucosal dissection via intraluminal endoscopy. Subsequently, the seromusclar layer was laparoscopically dissected on the exact three-fourths cut line around the tumor. The submucosal tumor then was exteriorized to the abdominal cavity and dissected with a standard endoscopic stapling device. RESULTS: In all cases, the LECS procedure was successful for dissecting out the gastric submucosal tumor. In four of seven cases, the tumor was located in the upper gastric portion near the esophagogastric junction. The remaining three tumors were in the posterior gastric wall. In two cases, the tumors were more than 5 cm in diameter, and one was a GIST of the remnant stomach. The mean operation time was 169 +/- 17 min, and the estimated blood loss was 7 +/- 2 ml. The postoperative course was uneventful in all cases. CONCLUSIONS: The LECS procedure for dissection of gastric submucosal tumors such as GIST may be performed safely with reasonable operation times, less bleeding, and adequate cut lines. In addition, the success of the procedure does not depend on the tumor location such as the vicinity of the esophagogastric junction or pyloric ring. 相似文献