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   2935篇
  免费   174篇
  国内免费   24篇
耳鼻咽喉   25篇
儿科学   70篇
妇产科学   61篇
基础医学   309篇
口腔科学   39篇
临床医学   173篇
内科学   837篇
皮肤病学   126篇
神经病学   169篇
特种医学   90篇
外科学   456篇
综合类   8篇
预防医学   107篇
眼科学   30篇
药学   305篇
中国医学   10篇
肿瘤学   318篇
  2023年   18篇
  2022年   33篇
  2021年   65篇
  2020年   42篇
  2019年   44篇
  2018年   68篇
  2017年   49篇
  2016年   60篇
  2015年   57篇
  2014年   76篇
  2013年   114篇
  2012年   169篇
  2011年   154篇
  2010年   89篇
  2009年   73篇
  2008年   153篇
  2007年   154篇
  2006年   149篇
  2005年   166篇
  2004年   144篇
  2003年   133篇
  2002年   151篇
  2001年   70篇
  2000年   71篇
  1999年   61篇
  1998年   35篇
  1997年   26篇
  1996年   25篇
  1995年   23篇
  1994年   15篇
  1993年   17篇
  1992年   48篇
  1991年   55篇
  1990年   48篇
  1989年   43篇
  1988年   44篇
  1987年   32篇
  1986年   60篇
  1985年   45篇
  1984年   21篇
  1983年   17篇
  1982年   13篇
  1979年   30篇
  1978年   27篇
  1977年   20篇
  1976年   12篇
  1975年   12篇
  1974年   11篇
  1972年   16篇
  1971年   12篇
排序方式: 共有3133条查询结果,搜索用时 31 毫秒
1.
Anthocyanins, which are responsible for a variety of bright colors (including red, blue, and purple) in fruits, vegetables, and flowers, are consumed as dietary polyphenols. Anthocyanin-containing fruits are thought to decrease coronary heart disease and are used in anti-diabetic preparations. Diabetes is associated with a variety of cardiovascular complications that may be mediated by endothelial dysfunction, and so this study was designed mainly to characterize the influence of a synthesized anthocyanidin derivative (HK-008) over acetylcholine (ACh)-induced relaxation in mesenteric arterial beds isolated from rats. In a glucose-tolerance test in intact rats, HK-008 (30 mg/kg) reduced the glucose level as effectively as the same dose of glibenclamide. The aortic relaxation induced by pinacidil (an ATP-sensitive potassium channel opener) was greatly inhibited by glibenclamide (10 microM), and also significantly inhibited by HK-008 (10 microM). Interestingly, the ACh-induced relaxation in the perfused, preconstricted mesenteric arterial bed was significantly enhanced by HK-008 (10 microM), and this enhancement was significantly attenuated by indomethacin (10 microM). The ACh-induced mesenteric relaxation was impaired by an increase in oxidative stress, viz. superoxide-generating treatment [xanthine oxidase (XO; 0.1 U/ml) plus hypoxanthine (HX; 10 microM)]. However, this impairment was strongly suppressed by HK-008 (10 microM). These results suggest that HK-008 increases endothelium-induced relaxation by suppressing oxidative stress or modulating prostanoids signaling. This compound may therefore be useful against certain cardiovascular disorders.  相似文献   
2.
The effect of metronidazole on TPN-associated liver dysfunction in neonates   总被引:3,自引:0,他引:3  
The effect of metronidazole (MNZ) on hepatic dysfunction associated with total parenteral nutrition (TPN) in neonates was investigated. Neonates receiving TPN for more than 2 weeks were divided into three groups. In group 1, TPN was given alone, in group 2, 25 mg/kg/d of MNZ was administered intravenously for the first 2 weeks of TPN, and in group 3, 50 mg/kg/d of MNZ was given for the first 3 weeks of TPN. Several parameters of liver function tests (LFTs) during the first 4 weeks of TPN were compared among these three groups. There was no significant difference of these parameters between group 1 and group 2. Although there was no significant difference of alkaline phosphatase, gamma-glutamyl transpeptidase, direct bilirubin, and total bile acid between groups 1 and 3, transaminase (glutamic oxaloacetic, glutamic pyruvic) of group 3 remained significantly lower than those of group 1. In conclusion, the administration of MNZ 50 mg/kg/d for 3 weeks, at least, prevented the elevation of transaminase during TPN in neonates, suggesting the possible involvement of intestinal anaerobic flora in the pathogenesis of TPN-associated liver dysfunction.  相似文献   
3.
We report a case of granulocyte-colony stimulating factor producing gastric cancer with multiple liver metastases. A 68-year-old woman who complained of epigastralgia visited our hospital. Upper gastrointestinal endoscopic examination revealed a type-2 gastric cancer. The laboratory data at admission indicated leukocytosis (35,900/microl) and a high level of serum granulocyte-colony stimulating factor (61 pg/mg). Granulocyte-colony stimulating factor producing gastric cancer was diagnosed by immunohistochemistry of biopsy specimen. Since we detected multiple liver metastases, chemotherapy was performed. Granulocyte-colony stimulating factor-producing gastric cancer is relatively rare and we summarize previous reports.  相似文献   
4.
In 97 neonates receiving total parenteral nutrition in the postoperative period, clinical assessment was made for a newly devised amino acid solution (PF-I-III) from the standpoint of plasma amino acid profile and nutritional effect. These amino acid solutions prepared are characterized by the high concentration of branched-chain amino acids up to 40%, increased arginine and decreased glycine, phenylalanine and methionine as compared with commercially available solutions. In the PF group, each amino acid was kept within the range of standard value. Correlation between plasma amino acid profiles and the dose of each amino acid administered was obtained, from which minimum, standard, and maximum doses for each amino acid was determined. Based on these values, we proposed new formula for neonates which elicits no abnormal plasma amino acid pattern even when amino acids are administered at the dosage level of 1.5-2.5 g/kg/day.  相似文献   
5.
To investigate the mechanism underlying increased endothelin-1 (ET-1) release in diabetic rats, we administered L-arginine chronically to streptozotocin (STZ)-induced diabetic rats. The plasma concentrations of glucose, ET-1 and NOx (NO2- + NO3-) were all significantly raised at 10 weeks after the STZ injection. Chronic administration of L-arginine resulted in a significantly higher plasma NOx concentration and a significantly lower plasma ET-1 level at 10 weeks compared with the untreated diabetic group. ET-1 induced a biphasic vasodilator/vasoconstrictor response in the perfused isolated mesenteric arterial beds from all groups. The vasodilatation was significantly greater in diabetic rats than in age-matched controls. Chronic oral L-arginine administration had no significant effect on the enhanced ET-1-induced vasodilatation seen in the untreated diabetic rats. The vasoconstrictions induced by ET-1 and methoxamine were significantly attenuated in STZ-diabetic rats. The attenuated vasoconstrictor response to ET-1, but not that to methoxamine, was further attenuated by chronic treatment with L-arginine. We conclude that since chronic L-arginine administration not only reduced the increase in plasma ET-1 levels but also further attenuated the ET-1-induced vasoconstriction without affecting the change in vasodilatation, chronic L-arginine administration could be valuable for the treatment of the symptoms of diabetic mellitus related to ET-1.  相似文献   
6.
Single photon emission computed tomography (SPECT) with N-isopropyl-p-[123I]-iodoamphetamine was performed twice at different times in 18 children suffering from partial seizures to evaluate the time-course changes of the hemodynamics in the focal region. Comparison of the 2 SPECT images revealed that a decreased regional cerebral blood flow (CBF) in the first was normalized in 4 cases (22.2%) and contracted in 7 cases (38.9%). The region of decreased blood flow in the second was contralateral to that in the first in 1 case (5.6%) and unchanged in 6 cases (33.3%). Most of the normalized and contracted cases were those in which clinical seizures disappeared and the EEG findings were normalized. In these cases which responded to treatment, the decreased regional CBF was also found to be improved. Repeated SPECT appears to be useful for evaluating the therapeutic efficacy. On the other hand, most of the unchanged cases were those in which clinical seizures were frequent or uncontrolled, or which persistently showed the abnormalities in their EEG. SPECT was considered to reflect well the conditions of the epileptic foci. These results indicate that repeated SPECT for observing the time-course changes of the regional CBF represents a useful technique with can be applied in evaluating the therapeutic efficacy or deciding the time to discontinue treatment and for pathogenetic elucidation of the epileptic foci.  相似文献   
7.
8.
Hepatoblastoma is the most common malignant liver tumor in children. Recently, liver transplantation has been indicated for unresectable hepatoblastoma. We retrospectively reviewed 14 children with a diagnosis of hepatoblastoma who had undergone living-donor liver transplantation (LDLT) at Kyoto University Hospital. During the period from June 1990 to December 2004, 607 children underwent LDLT. Of these interventions, 2.3% were performed for hepatoblastoma. Based on radiological findings, the pre-treatment extent of disease (PRETEXT) grouping was used for pre-treatment staging of the tumor. There were grade III in seven patients and grade IV in seven patients. Thirteen patients received chemotherapy, and seven underwent hepatectomy 11 times. Immunosuppressive treatment consisted of tacrolimus monotherapy in 11 patients. Actuarial 1- and 5-year graft and patient survival rates were 78.6% and 65.5%. The poor prognostic factors were macroscopic venous invasion and extrahepatic involvement with 1-year and 5-year survival rates of 33.0% and 0%. Pediatric patients without these factors showed an acceptable 5-year survival rate of 90.9%. LDLT provides a valuable alternative with excellent results in children with hepatoblastoma because it allows optimal timing of the liver transplantation, given the absence of delay between the completion of chemotherapy and planned liver transplantation.  相似文献   
9.
Pyogenic granuloma is one of the diseases sometimes seen in otorhinolaryngology clinics. The clinical features of this disease are understood to be that the lesion is located in the oral cavity in the majority of cases that its causative agent is usually discovered and that it most likely grows as a malignant tumor. However, the entity of pathological diagnosis has not been established. Thirty-one cases of oral pyogenic granuloma, including 16 males and 15 females, are reported in this paper. The granuloma was located most frequently at the tongue, followed, in order, by the gingiva, buccal mucosa, hard palate, lip and oral floor. The period between the patient's first visit to our clinic and the onset of his/her complaint was variable. It was relatively shorter in those cases with the lesion at the gingiva or tongue as compared to other locations. The size of the lesion was smaller than 10 x 10 mm. We classified the pathological features into three patterns; granuloma type, hemangioma type, and intermediate type. Many cases of lesions located at the back of the tongue, buccal mucosa, or hard palate were of the hemangioma type, while many cases of lesions located at the top of the tongue, gingiva, or oral floor were of the granuloma type. We have the impression that pyogenic granuloma could be one of the purulent changes associated with benign oral tumors.  相似文献   
10.
Analysis of DNA ploidy patterns was performed on 76 diffusely infiltrating carcinomas of the stomach and the results correlated with histologic findings and outcome. Twenty six cases were diploid (34%) and 50 cases were aneuploid. There was no correlation between DNA ploidy and histologic type, depth of invasion, lymphatic invasion, evidence of peritoneal dissemination or curability. In aneuploid tumors, incidence of vascular invasion was significantly higher than that in diploid tumors (p less than 0.05). In addition, the patients with aneuploid tumors had a poor prognosis than with diploid tumors. These results indicate that DNA ploidy patterns may possibly be a useful prognostic marker for diffusely infiltrating carcinomas of the stomach.  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