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   708篇
  免费   21篇
  国内免费   1篇
儿科学   115篇
妇产科学   1篇
基础医学   30篇
口腔科学   4篇
临床医学   81篇
内科学   174篇
皮肤病学   6篇
神经病学   55篇
外科学   125篇
综合类   4篇
预防医学   3篇
眼科学   2篇
药学   75篇
中国医学   4篇
肿瘤学   51篇
  2018年   1篇
  2017年   4篇
  2016年   9篇
  2015年   14篇
  2014年   9篇
  2013年   14篇
  2012年   4篇
  2011年   3篇
  2010年   15篇
  2009年   18篇
  2008年   4篇
  2007年   27篇
  2006年   38篇
  2005年   19篇
  2004年   33篇
  2003年   24篇
  2002年   10篇
  2001年   9篇
  2000年   3篇
  1999年   32篇
  1998年   65篇
  1997年   41篇
  1996年   51篇
  1995年   42篇
  1994年   39篇
  1993年   37篇
  1992年   15篇
  1991年   15篇
  1990年   13篇
  1989年   6篇
  1988年   8篇
  1987年   10篇
  1986年   10篇
  1985年   8篇
  1984年   6篇
  1983年   4篇
  1982年   5篇
  1981年   13篇
  1980年   10篇
  1979年   14篇
  1978年   5篇
  1977年   2篇
  1976年   5篇
  1975年   2篇
  1973年   2篇
  1972年   4篇
  1971年   3篇
  1970年   2篇
  1968年   1篇
  1967年   2篇
排序方式: 共有730条查询结果,搜索用时 15 毫秒
1.
We report a case of a patient in whom endoscopic band ligation was achieved for postpolypectomy gastric bleeding. A 76‐year‐old man visited our hospital because of anemia. Endoscopy revealed a gastric polyp, approximately 12 mm in diameter, on the lesser curvature in the distal gastric body. The polyp was considered to be the source of chronic anemia and was therefore removed by using standard careful snare‐cautery polypectomy technique. Four days later, follow‐up endoscopy was performed to evaluate the postpolypectomy site, and an active bleeding postpolypectomy ulcer was identified. Initial attempts to achieve hemostasis with ethanol injection were unsuccessful. Immediate hemostasis was obtained with a subsequent endoscopic band ligation device. There has been no recurrent bleeding. Endoscopic band ligation might be a good treatment modality for the treatment of a postpolypectomy gastric bleeding lesion.  相似文献   
2.
Background and Aim: This study investigated the clinical features of hepatocellular carcinoma in patients with sustained virological response to interferon for hepatitis C viral (HCV) infection. Methods: A total of 7715 patients with HCV infection were treated with interferon and followed up for more than 1 year after withdrawal of interferon in 64 Japanese hospitals and clinics between July 1988 and August 2001. Sustained virological response was obtained in 2515 (32.6%) patients. Of these 2515 patients, clinical data were collected for 38 patients in whom hepatocellular carcinoma developed. Sustained virological response was defined as HCV RNA negativity more than 6 months after the termination of interferon. Results: All patients were HCV RNA negative at the time of diagnosis of hepatocellular carcinoma. The median period until the detection of hepatocellular carcinoma was 4.7 years (range 1.4–9.0 years). There were significant improvements in hepatic function including serum albumin, aspartate aminotransferase, alanine aminotransferase, indocyanine green test, platelet count and histological activity grade in comparison with those before interferon therapy and at the onset of hepatocellular carcinoma. The maximum tumor size in patients without medical follow‐up for 1 year or more (median: 60 mm) was significantly larger than in patients who were periodically followed up for 6 months or less (median: 25 mm) (P = 0.002). Conclusions: The present findings emphasize the importance of regular medical follow up of patients with HCV infection, as even patients showing a sustained virological response to interferon and in whom hepatic function has improved have the potential to develop hepatocellular carcinoma.  相似文献   
3.
Background:  Bleeding is one of the main symptoms of internal hemorrhoids. However, the conventional Goligher's classification of internal hemorrhoids does not consider the severity of bleeding. We intended to establish a useful method for evaluating internal hemorrhoids using a colonoscope that reflected the severity of the symptoms.
Methods:  Using a colonoscope in the retroflexed and forward viewing position, 104 patients with symptomatic internal hemorrhoids were evaluated based on the criteria of range, form and red color signs (RCS). Range was determined by the circumferential distribution of internal hemorrhoids and scaled from 0 to 4. Form was determined by size and scaled from 0 to 2. The presence of RCS was also evaluated. Symptoms were determined by interview and scaled from 0 to 3. Patients were treated by endoscopic band ligation (EBL) and were examined endoscopically before and 4 weeks after the treatment.
Results:  Before the treatment, range, form and RCS were significantly correlated to bleeding ( P <  0.01), and form was significantly correlated to prolapse ( P <  0.05). The endoscopic classification scores at 4 weeks after EBL improved significantly (range from 3.25 ± 0.05–0.56 ± 0.08 [ P <  0.01] and form from 2.81 ± 0.04–0.56 ± 0.07 P <  0.01).
Conclusion:  The new endoscopic classification of internal hemorrhoids proved to be closely correlated to symptoms, particularly bleeding, and thus highly useful in evaluating the effectiveness of the treatment.  相似文献   
4.
The locations of the three disulfide bonds of eclosion hormone (EH) isolated from Manduca sexta were assigned by sequence analysis of thermolysin fragments and by comparison of a key heterodimeric fragment to regiospecifically synthesized parallel and antiparallel isomers. We elucidated the complete structure of Manduca EH as a 62-residue peptide which has three disulfide bonds between Cys14-Cys38, Cys18-Cys34, and Cys21-Cys49.  相似文献   
5.
Abstract Relationships between urinary levels of α1-microglobulin (α1M) and ulinastatin (UT) in patients with dementia were investigated. There were no significant differences in α1M and UT levels and α1M: UT ratios among three groups: age-matched control subjects, patients with either Alzheimer-type senile dementia (ATD) or vascular dementia (VD). Although a positive correlation was established between α1M and UT levels in these groups, the regression of the demented patients differed significantly from that of controls ( P <0.05). A tendency towards a negative correlation between α1M: UT ratios and the levels of severity or duration of the disease was displayed in the ATD group, whereas a tendency toward a positive correlation between α1M: UT ratios and the levels of severity was observed in the VD group. These results suggest that changes in the relationships between urinary levels of α1M and UT may provide a useful biochemical index for diagnoses of ATD and VD.  相似文献   
6.
Four infants with severe intrauterine growth retardation (IUGR) weighing less than 1000 g at birth developed heart failure and died in our unit, where heart failure of IUGR infants is the main reason of death in extremely low birth-weight infants. The causes of their heart failure are one of the main themes in current neonatal medicine. The subjects of this study were four small for gestational age infants; all died due to heart failure 5 to 10 days after birth. Microscopic specimens of hearts from autopsies were evaluated with respect to the following characteristics: thickness of myocardial fibers, maturation of nuclei, presence of dysgenesis or necrosis in myocardium, and amount of glycogen in the heart. Neither dysgenesis nor infarction of the heart was found but hypoplasia in myocardial fibers and decreased glycogen levels were observed. Maturation delay in myocytes' nuclei did not appear to be severe. We conclude that these infants' hearts failed to adapt to postnatal hemodynamic changes because of inadequate myocardial function and inadequate glycogen reserves.  相似文献   
7.
8.
AIM: The aim of the present study was to investigate the safety and efficacy of endoscopic laser therapy for transitional cell carcinoma (TCC) of the upper urinary tract. METHODS: Tumors of the renal pelvis and ureteropelvic junction were detected by ureteroscopy. The tumors were subjected to biopsy, and after TCC was diagnosed, endoscopic laser therapy (Neodymium-YAG and Holmium-YAG) was conducted using a 6.9 Fr. flexible ureterorenoscope. RESULTS: From January 1997 to April 2002, six patients underwent ureteroscopic treatment. Tumor grade was 1 in four patients and 2 in two patients. Average tumor size was 1.45 cm. Endoscopic treatment was chosen for two patients because of the high medical risk associated with open surgery. Another patient underwent diagnostic ureteroscopy, followed immediately by endoscopic treatment. A further three patients elected to undergo ureteroscopic treatment. One patient with large (3 cm), multifocal and incompletely treated tumors died of metastatic disease 22 months after the initial operation. One patient requested nephroureterectomy one month after endoscopic treatment, and pathological examination of the resected specimen revealed no tumor. The other four patients have been followed up for a mean period of 14 months after initial treatment. Recurrence occurred in one patient, and was successfully treated by repeat endoscopic resection. None of the patients required blood transfusion or emergency open surgery. CONCLUSION: Ureteroscopic treatment of small, localized, low-grade TCC of the upper urinary tract is now a safe and feasible alternative to nephroureterectomy in selected patients.  相似文献   
9.
In the present study, we examined the effect of amantadine on extracellular dopamine levels in the rat striatum using an in vivo microdialysis. Perfusion of amantadine (0.1–1 mM) through the microdialysis probe caused an increase both in extracellular dopamine and glutamate levels in rat striatum. Amantadine was found to increase extracellular dopamine concentration in Ca2+-dependent manner, but the effect was not abolished by ω-conotoxin. Although intraperitoneal administration of MK-801 [(+)-5-methyl-10,11-dihydroxy-5H-dibenzo(a,d)cyclohepten-5,10-imine] alone could not significantly alter the concentration of dopamine, it attenuated amantadine-induced increase in dopamine level. These findings suggest that an interaction between dopaminergic and glutamatergic neurotransmission is an important component in the regulation of striatal dopamine levels. Copyright © 1996 Elsevier Science Inc.  相似文献   
10.
The proliferation sites and cellular kinetics of villous epithelial cells and M cells in the intestine of the adult chicken have never been clarified. In this study, we determined the proliferation sites in the chicken caecum using colchicine treatment and detection of proliferative cell nuclear antigen (PCNA). The cellular kinetics of these cells were also studied using bromodeoxyuridine (BrdU) as a tracer. Enterocytes in their mitotic period were observed along the entire length of the intestinal crypt of the caecum, with a denser distribution in the middle portion of the crypt, except for the caecal tonsil. The centres of distributions were at 49% of the distance from the bottom of the crypt in the base and 41% in the apex of the caecum. In the caecal tonsil, the centres of distributions were at 64% in the long type of crypt from the bottom of the crypt and at 44% in the short type of crypt. On the other hand, the PCNA-positive enterocytes were distributed more densely at the bottom of the crypt, except for the caecal tonsil. The centres of distributions were at 36% in the base from the bottom of the crypt, 37% in the body, and 34% in the apex. In the caecal tonsil, they were at 54% in the long type of crypt and 44% in the short type. The BrdU-labelled enterocytes reached to the basement of the intestinal villi in all caecal portions at 1 d after the BrdU administration. The leading edge of the labelled enterocytes disappeared from the villous tips at 4 d in the base and the body and 3 d in the apex. In the caecal tonsil, the BrdU-labelled microvillous epithelial cells and the M cells appeared near the orifice of the crypt at 1 d, and BrdU-labelled M cells were not observed in the crypt. Thereafter, almost all of these cells disappeared at 5 d from the follicle associated epithelium (FAE). These results suggest that M cells are transformed from their precursors within 1 d, and the turnover time for M cells occurs within 4 d after the cell division of the precursors.  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