首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   7963篇
  免费   365篇
  国内免费   80篇
耳鼻咽喉   49篇
儿科学   235篇
妇产科学   124篇
基础医学   969篇
口腔科学   253篇
临床医学   453篇
内科学   2329篇
皮肤病学   84篇
神经病学   578篇
特种医学   340篇
外科学   1341篇
综合类   24篇
预防医学   152篇
眼科学   101篇
药学   413篇
中国医学   19篇
肿瘤学   944篇
  2023年   61篇
  2022年   116篇
  2021年   196篇
  2020年   105篇
  2019年   171篇
  2018年   193篇
  2017年   171篇
  2016年   215篇
  2015年   183篇
  2014年   281篇
  2013年   309篇
  2012年   497篇
  2011年   559篇
  2010年   354篇
  2009年   289篇
  2008年   462篇
  2007年   479篇
  2006年   496篇
  2005年   539篇
  2004年   518篇
  2003年   459篇
  2002年   450篇
  2001年   88篇
  2000年   93篇
  1999年   98篇
  1998年   97篇
  1997年   71篇
  1996年   64篇
  1995年   56篇
  1994年   48篇
  1993年   43篇
  1992年   47篇
  1991年   46篇
  1990年   45篇
  1989年   60篇
  1988年   53篇
  1987年   46篇
  1986年   30篇
  1985年   28篇
  1984年   22篇
  1983年   22篇
  1982年   35篇
  1981年   23篇
  1980年   18篇
  1979年   25篇
  1978年   24篇
  1977年   23篇
  1975年   15篇
  1974年   11篇
  1972年   13篇
排序方式: 共有8408条查询结果,搜索用时 15 毫秒
951.
Prolonged acute hepatitis A mimicking autoimmune hepatitis   总被引:1,自引:0,他引:1  
AIM: We report a case with a prolonged course of hepatitis A, with alanine aminotransferase (ALT) higher than 500 IU/L for more than 2 mo. METHODS: A middle-aged woman had an elevated IgG level of more than 2 000 mg/dL, positive anti-nudear antibodies (ANA) and anti-smooth muscle antibodies (ASMA), but no evidence of persistent hepatitis A virus (HAV) infection. Liver biopsy findings were compatible with prolonged acute hepatitis, although acute onset of autoimmune hepatitis could not be ruled out. RESULTS: It was assumed that she developed a course of hepatitis similar to autoimmune hepatitis triggered by HAV infection. Ursodeoxycholic acid (UDCA) treatment was initiated and a favorable outcome was obtained. CONCLUSION: We describe a case of a middle-aged woman who showed a prolonged course of acute hepatitis A mimicking autoimmune hepatitis. Treatment with UDCA proved to be effective.  相似文献   
952.
The effects of a newly synthesized peptide, human gastrin-releasing peptide (hGRP), on the pancreatic exocrine secretion and the release of pancreatic polypeptide (PP) were examined in the conscious rat. Plasma PP concentrations were determined by a recently established specific radioimmunoassay for rat PP. Amounts of 0.18, 0.35, and 3.5 nmol/kg/h hGRP significantly stimulated both pancreatic exocrine secretion and 0.35 nmol/ kg/h of hGRP increased PP release. Simultaneously infused proglumide (300 mg/kg/h) did not affect either pancreatic exocrine secretion or PP release. However, simultaneous infusion of atropine (100 μg/kg/h) slightly inhibited PP release, but did not restrict the incremental response of pancreatic protein secretion to hGRP. These results suggest that hGRP directly stimulates pancreatic exocrine secretion and PP release.  相似文献   
953.
BACKGROUND/AIMS: Orthotopic liver transplantation (OLTx) from non-heart beating donor (NHBD) often involves hepatic warm ischemia and reperfusion injury which is triggered by the inflammatory cytokines. This study was carried out to investigate whether a newly synthesized cytokine suppressive anti-inflammatory agent, FR167653, attenuates graft injury in OLTx from NHBD. METHODOLOGY: Porcine OLTx from NHBD was performed. No-heart beating time was scheduled to be 60 minutes. Animals were divided into two groups: no treatment control (CT) group (n=5), and FR167653 treated (FR) group (n=5), in which FR167653 was administered intravenously before the aortic cross clamp in the donor, and before and after the hepatic allograft reperfusion in the recipient continuously. RESULTS: Four out of five pigs died within 24 hours and one on postoperative day 1 from graft liver failure in the CT group, while two pigs died on day 3, and three survived more than 7 days in the FR group (p<0.05). Microcirculatory disturbance was attenuated, liver injury was lessened, and ATP resynthesis was enhanced in the FR group. Additionally, FR167653 inhibited neutrophils infiltration in the liver tissue, and suppressed release of inflammatory cytokines after OLTx from NHBD. CONCLUSIONS: The treatments with FR167653 successfully prevented graft injury after OLTx from NHBD by means of improvement of liver microcirculation, and attenuation of neutrophils activation. The inhibitory effect of FR167653 on the release of inflammatory cytokines played an important role in the liver graft protection.  相似文献   
954.
BACKGROUND: A novel program, "cardioGRAF", has been developed to analyze regional left ventricular (LV) systolic/diastolic function and dyssynchrony, so the present study aimed to use it confirm the presence of LV dyssynchrony, and to correlate LV function and dyssynchrony with plasma B-type natriuretic peptide (BNP) levels during the early to advanced stages of heart failure (HF). METHODS AND RESULTS: Fourteen control subjects (G-C) and 50 patients (New York Heart Association functional class I: G-1, 21 patients; class II: G-2, 15 patients; and class III: G-3, 14 patients) were examined by ECG-gated myocardial perfusion single-photon emission computed tomography, using the new index of dyssynchrony, maximal difference (MD), which is the difference between the earliest and latest temporal parameters among 17 segments. First-third filling rate (FR) and the MD of time to peak FR revealing diastolic dyssynchrony were significantly different between G-C subjects and G-1 patients. Ejection fraction, peak ejection rate, peak FR, MD of time to end-systole, and MD of time to peak ejection rate were significantly correlated with plasma BNP levels. CONCLUSION: Diastolic dyssynchrony was demonstrated even in the early stage of HF, but, although not correlated with the plasma BNP level, systolic dyssynchrony might affect it.  相似文献   
955.
Continuous hemodiafiltration (CHDF) is an essential procedure in critical care. However, application of this therapy to pediatric patients is associated with several problems derived from their smaller body size and weight compared with adults. We have successfully conducted CHDF in pediatric patients including newborns by taking such problems into consideration and carefully coping with them. The present study consisted of 60 pediatric patients treated with CHDF. Clinical efficacy and safety of CHDF in pediatric patients were assessed in these patients by reviewing patient clinical records. The 60 patients treated with CHDF included 27 males and 33 females. Their body weight ranged from 700 g to 53.0 kg. The mean CHDF duration was 6.80 +/- 6.94 days. Blood access was provided in a veno-venous mode in 42 patients, and an arterio-venous mode in 18 patients. Of the 60 pediatric patients receiving CHDF, 31 patients survived without serious complications, achieving a survival rate of 51.7%. Successful CHDF in pediatric patients was achieved by careful and exact execution of the following countermeasures to overcome problems specific to application of this therapy to pediatric patients: minimization of the priming volume; use of colloid solutions or whole blood as priming solution; maintaining secure blood access; selection of an appropriate anticoagulant; temperature control of both the patient's body and components of the hemofiltration circuit. In pediatric critical care, CHDF is safely applicable to the critically ill and expected to produce a wide spectrum of clinical efficacy just as in adults.  相似文献   
956.
957.
We report a 71-year-old man with reactive AA amyloidosis secondary to rheumatoid arthritis who developed spontaneous pneumoperitoneum with intestinal pseudo-obstruction as an initial symptom. Severe deposition of amyloid in the intestinal wall was considered to play an important role in the pathogenesis of this unusual symptom. The patient has been successfully treated with total parenteral alimentation and intermediate-dose prednisolone (30 mg/day). Although pneumoperitoneum usually suggests gastrointestinal perforation requiring emergency surgery, conservative therapy should be seriously considered in amyloidosis-related cases with no associated peritonitis, since multiple vital organs are probably involved by severe amyloid deposition, thus increasing the risks of surgery.  相似文献   
958.
BACKGROUND/AIMS: The practice of living-donor liver transplantation has been widely established. However, in adult cases, the issue of graft liver volume has been raised. Recently, liver transplantation using the right lobe has been done in cases requiring a larger graft volume. We compared right lobectomy with left lobectomy for hepatocellular carcinoma not accompanied by liver cirrhosis and examined the safety of hepatic right lobectomy for donation. METHODOLOGY: In total, 124 hepatocellular carcinoma patients without liver cirrhosis, 89 who had undergone right hepatectomy and 35 who had undergone left hepatectomy, were studied. For each group, we statistically examined the patients' profiles. RESULTS: The resected right lobe was significantly heavier than the left lobe. There were significant differences between the two groups in terms of the number of blood transfusions needed. Moreover, delayed recoveries in terms of hemoglobin, total bilirubin, and clotting disorder on postoperative day 7, as well as the frequency of any complications, were more prevalent in the right-lobe group. CONCLUSIONS: It was confirmed that right lobectomy is more invasive than left lobectomy. It is necessary to prioritize the donor's safety and quality of life in living-donor liver transplantation, and adequate medical and ethical consideration is demanded.  相似文献   
959.
Although previous studies have demonstrated that even quantitative coronary angiography (QCA) can not provide accurate disease morphology, there has not been a systematic comparison of disease morphology determined by QCA and intravascular ultrasound (IVUS), particularly in Japanese patients. Therefore, the present study prospectively examined patients in a multicenter cooperative study. A total of 491 coronary sites from 562 patients (446 men, 116 women; mean age, 64+/-11 years) who underwent coronary interventions were enrolled. The target lesions (>50% diameter stenosis) were evaluated pre-operatively by both QCA and IVUS operating at 30-40 MHz and the percent area stenosis, eccentricity index (EI) and lesion length were determined. The minimal (min) and maximal (max) distances from the center of the stenotic lesion to the outline of the vessel wall were measured, and the EI was calculated by the formula: [(max - min)/max]. By QCA, lesion length was determined by measuring the distance between the proximal and distal shoulders of the lesion. When the lesions were observed by IVUS with a motorized pull-back system, the length was calculated by multiplying the time for observation of the disease and 0.5 or 1 mm/s. Although the severity of the stenosis determined by QCA (86+/-10%, mean +/- SD) did not differ from that by IVUS (83+/-13%), there was no correlation between them (r=0.32, y=0.25x+65) and the correlation did not improve when lesions with remodeling, enlargement (n=176) or shrinkage (n=79) were omitted from the calculation. The EIs by QCA and IVUS were 0.51+/-0.26 and 0.52+/-0.22, respectively (NS), and there was no correlation between them (r=0.30, y=0.36x+33). However, when the lesions with remodeling were excluded, the correlation greatly improved (r=0.80, y=0.84x+10.6, p<0.05). Lesion length determined by QCA (12.4+/-6.1 mm) was significantly shorter than that by IVUS (16.3+/-8.9 mm, p<0.01). These results demonstrate that coronary angiography significantly misinterprets disease morphology in terms of severity, eccentricity and length, in part because of vessel remodeling that can be accurately determined only by IVUS.  相似文献   
960.
A considerable number of false negative cases in FDG-PET were seen in small-cell lung cancer, despite the usefulness of this imaging modality. We investigated the correlation between FDG-PET results and the clinicopathological findings in small lung cancers less than 3 cm in size. Fifty-one consecutive cases of surgically resected small lung cancers scanned preoperatively by FDG-PET was assessed. The medical records of each case were reviewed for the maximum tumor size in the CT findings, histology, grade of differentiation, lymphatic and vascular invasion, pleural invasion, lymph node stage, serum level of carcinoembryonic antigen (CEA), and CT findings. All of the 5 cases (4 adenocarcinomas, 1 small-cell carcinoma) less than 1 cm in size were false negatives. In the 46 cases 1-3 cm in size (34 adenocarcinomas, 9 squamous sell carcinomas, 2 large sell carcinomas, 1 small cell carcinoma), false negative results were seen in 8 of 15 cases of well-differentiated adenocarcinoma (53%). In the 8 false negative cases, 1 (13%) lymphatic vessel invasion (ly), 0 (0%) vascular vessel invasion (v), 0 (0%) pleural invasion (p), 0 (0%) lymph node metastasis, 0 (0%) high serum level of CEA, and 5 (63%) cases showing ground-glass opacity on CT were observed. There were significant differences in the factors ly, v, CEA, and CT findings between the 8 false-negative cases and the 26 true positive cases with adenocarcinoma (p < 0.01-0.05). Lung cancers < 1 cm in size cannot be detected in FDG-PET. Adenocarcinomas of the lung 1-3 cm in size with false negatives in FDG-PET showed significantly less invasiveness than the true positives.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号