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   3982篇
  免费   120篇
  国内免费   9篇
耳鼻咽喉   96篇
儿科学   70篇
妇产科学   45篇
基础医学   576篇
口腔科学   88篇
临床医学   221篇
内科学   785篇
皮肤病学   150篇
神经病学   209篇
特种医学   116篇
外科学   903篇
综合类   21篇
预防医学   85篇
眼科学   60篇
药学   308篇
中国医学   7篇
肿瘤学   371篇
  2023年   14篇
  2022年   25篇
  2021年   66篇
  2020年   44篇
  2019年   46篇
  2018年   59篇
  2017年   52篇
  2016年   52篇
  2015年   64篇
  2014年   103篇
  2013年   132篇
  2012年   195篇
  2011年   212篇
  2010年   114篇
  2009年   133篇
  2008年   196篇
  2007年   228篇
  2006年   239篇
  2005年   266篇
  2004年   245篇
  2003年   273篇
  2002年   243篇
  2001年   84篇
  2000年   98篇
  1999年   103篇
  1998年   63篇
  1997年   56篇
  1996年   47篇
  1995年   46篇
  1994年   37篇
  1993年   18篇
  1992年   55篇
  1991年   64篇
  1990年   48篇
  1989年   48篇
  1988年   52篇
  1987年   41篇
  1986年   38篇
  1985年   29篇
  1984年   20篇
  1983年   19篇
  1982年   17篇
  1981年   8篇
  1980年   9篇
  1979年   10篇
  1978年   13篇
  1977年   9篇
  1974年   10篇
  1967年   8篇
  1966年   8篇
排序方式: 共有4111条查询结果,搜索用时 31 毫秒
61.
Background/Objective: The feces sign has been reported as a possible predictive factor for non-operative treatment of small bowel obstruction. However, its relationship with prognosis of non-emergency adhesive small bowel obstruction remains unclear. This study aimed to clarify the relationship between the feces sign and prognosis of non-emergency adhesive small bowel obstruction.MethodsNinety-two patients with non-emergency adhesive small bowel obstruction with the transitional zone visible on computed tomography were included. Patients were categorized into two groups: feces sign positive (n = 40) and negative (n = 52). Clinical features and prognosis were compared between the two groups. Cox proportional hazards regression models incorporating the feces sign were used to analyze odds of diet resumption and discharge.ResultsPatients with feces sign were younger (p = 0.015), had a higher body mass index (p = 0.027), and a lower white blood cell count (p = 0.019) on admission. More patients with feces sign were successfully treated with fasting and/or nasogastric tube placement (p < 0.001), and no patient with feces sign suffered from recurrent obstruction after diet resumption. Kaplan–Meier analysis showed that patients with feces sign took less time for diet resumption (p = 0.007) and discharge (p = 0.004) than those without it. Using Cox proportional hazards regression model, the feces sign was reported as an independent predictor of diet resumption (odds ratio 1.685, p = 0.018) and discharge (odds ratio 1.861, p = 0.007).ConclusionsThe feces sign is associated with improved odds for diet resumption and discharge.  相似文献   
62.
A quantitative analysis was made of the myelinated fibers in the lateral corticospinal tract (LCST) at the levels of the 6th cervical, 7th thoracic and 4th lumbar spinal segments in 20 patients between 19 and 90 years old, and who died of non-neurological diseases. The diameter frequency histograms of myelinated fibers of LCST showed a bimodal pattern with a sharp peak of the small myelinated fibers and broad slope of the large myelinated fibers. The ratio of small fiber to large fiber densities was significantly higher in the 6th cervical (P<0.05) and 4th lumbar segments (P<0.01) than in the 7th thoracic segments. The density of small myelinated fibers was significantly lowered with advancing age (P<0.050.001), while that of large myelinated fibers was not significantly decreased in the aged patients, although it showed a slight age-dependent declining tendency. Age-dependent decline of small fiber density was more prominent in the cervical and lumbar segments. Retraction of the axon-collaterals from large-diameter myelinated fibers, which are abundant in the cervical and lumbar segments, may contribute to the age-related diminution of the small myelinated fibers in the LCST.Part of this work was supported by grants from the Ministry of Welfare and Health of Japan, and a grant from Uehara Memorial Research Foundation  相似文献   
63.
A 32-year-old man consulted Osaka National hospital with chief complaints of dysuria and macrohematuria. DIP and CT revealed that the right kidney deviated to the lower pole of the left kidney and they fused together. The right ureter crossed over the supine. The calcified shadow existed in the lower end of the left ureter with cobra head image. He had no external anomalies. Under diagnosing crossed fused kidney (inverted L shaped) complicated the left ureterocele with a stone, transurethral incision of ureterocele (TUI) was performed. We made transverse incision and extracted stone, 7 mm in size (calcium oxalate 96% and calcium phosphate 4%). Three months later after the operation, IVP, CG and VCG revealed the down-sized ureterocele and no VUR. Crossed renal ectopia complicated many anomalies about 50%. Among them anomalies of the urinary tract was most frequent about 30%. But crossed renal ectopia with ureterocele wasn't reported so far in Japanese literature.  相似文献   
64.
Cognitive functioning in autistic subjects was investigated by employing ERP recordings. The sample included four autistic patients, with five normal subjects and four Down's syndrome patients serving as the two control groups. The P300 component was investigated under three different experimental conditions, that is; “No-task,” “Counting,” and “Key-press. ” Two out of four autistic subjects were able to perform the required task under the Counting condition. However, none of them were able to complete the task for the Key-press condition. Autistic subjects demonstrated a lower amplitude of the P300 component under the No-task condition as compared to the other two groups. It was speculated that the autistic, as opposed to the other two groups, had some cognitive difficulties in the “active stimulus evaluating process”.  相似文献   
65.
Summary In the present study we examined the effects of pirarubicin [(2R)-4-0-tetrahydropyranyladriamycin, THP] on a cardiovascular system. An injection of THP (0.39–3.13 mg/kg, i. v.) reduced the mean blood pressure and caused an increase in the respiratory air rate in anesthetized rats. At 1.5×10–6–1.5×10–5 m, THP markedly relaxed a contraction induced by 10–7 m norepinephrine in rat aorta with endothelium but not in that without endothelium. At a dose of 0.02–0.5 mg, THP produced an increase in the contractile force and the perfusion flow of isolated perfused guinea pig hearts. At a higher concentration (4.5×10–5–1.5×10–4 m), it produced a slight increase in the contractile force of the left atria in guinea pigs. This positive inotropic action of THP was inhibited by diphenhydramine (10–6–5×10–5 m), chlorpheniramine (3×10–7–3×10–5 m), and tripelennamine (3×10–7–3×10–5 m) but not by propranolol (10–6 m), cimetidine (10–5 m), diltiazem (10–6 m), or ryanodine (10–8 m). THP given i. v. at 2.5 mg/kg elevated the plasma histamine level in anesthetized dogs. From these data, we conclude that THP mainly relaxed the rat aorta in the presence of endothelium and that at higher concentrations, it increased the contractile force in the cardiac muscle, probably mediated through the release of histamine.  相似文献   
66.
PURPOSE: Although hepatocellular carcinoma (HCC) is the most common cancer of the human liver, the mechanisms that regulate HCC development and progression remain unclear. The aim of this study was to investigate whether focal adhesion kinase (FAK) is involved in the progression of human HCC. EXPERIMENTAL DESIGN: Western blot analysis for FAK was performed on three HCC cell lines. We reviewed 64 consecutive patients who had undergone initial liver resection for HCC without preoperative treatment. Immunohistochemistry analysis for FAK was performed on paraffin-embedded tissues. FAK expression was confirmed by Western blot analysis in several clinical samples. We investigated the correlation between FAK expression and clinical outcome. RESULTS: FAK proteins were detected in all HCC cell lines. Hepatocytes in the normal liver and chronic hepatitis with or without cirrhosis were negative for immunohistochemical staining for FAK expression. Cytoplasmic FAK expression was observed in 18 of 64 patients (28.1%), and this positive staining was correlated with gender (P < 0.05), a lower level of serum albumin (P < 0.05), and portal venous invasion (P < 0.01). Positive staining for FAK was associated with significantly poorer survival (P < 0.05). In multivariate analysis, FAK overexpression was an independent factor in determining the prognosis of patients. CONCLUSIONS: These data suggest that FAK plays an important role in promoting tumor progression, especially vascular invasion, in HCC. FAK could play an important role in HCC progression and would be a novel target for HCC therapeutics as well as a prognostic marker.  相似文献   
67.
BACKGROUND: Hepatic artery thrombosis (HAT) remains an important cause of graft loss after liver transplantation. Emergency rearterialization methods are limited in cases of living-related liver transplantation in which the graft hepatic artery is thin and short. CASE: A 19-year-old woman who underwent living-related liver transplantation for biliary atresia developed HAT on the 4th postoperative day. During the emergency laparotomy the recipient hepatic artery was found to be too short to anastomose, so the recipient's right gastroepiploic artery was anastomosed to the graft hepatic artery. The patient is now alive and well 6 months after reoperation, and she has experienced no further episode of HAT. CONCLUSION: The right gastroepiploic artery can be used easily and safely for hepatic graft revascularization without causing ischemia of the stomach. An additional skin incision is not required, and the artery is long enough to anastomose to the graft artery directly. The method of hepatic graft rearterialization described here is an important option for patients who undergo living-related or split liver transplantation.  相似文献   
68.
69.
70.
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