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   973篇
  免费   48篇
  国内免费   9篇
耳鼻咽喉   23篇
儿科学   38篇
妇产科学   73篇
基础医学   119篇
口腔科学   45篇
临床医学   87篇
内科学   132篇
皮肤病学   58篇
神经病学   50篇
特种医学   50篇
外科学   110篇
综合类   22篇
预防医学   26篇
眼科学   31篇
药学   67篇
中国医学   3篇
肿瘤学   96篇
  2023年   7篇
  2022年   18篇
  2021年   32篇
  2020年   22篇
  2019年   30篇
  2018年   35篇
  2017年   18篇
  2016年   38篇
  2015年   26篇
  2014年   40篇
  2013年   53篇
  2012年   87篇
  2011年   89篇
  2010年   55篇
  2009年   48篇
  2008年   61篇
  2007年   55篇
  2006年   59篇
  2005年   55篇
  2004年   45篇
  2003年   28篇
  2002年   35篇
  2001年   14篇
  2000年   10篇
  1999年   4篇
  1998年   5篇
  1997年   5篇
  1996年   9篇
  1995年   3篇
  1992年   14篇
  1991年   2篇
  1990年   3篇
  1989年   4篇
  1986年   1篇
  1985年   2篇
  1984年   1篇
  1983年   3篇
  1982年   2篇
  1979年   5篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1940年   1篇
  1938年   1篇
  1936年   1篇
排序方式: 共有1030条查询结果,搜索用时 0 毫秒
91.
Background: Many patients experience pain on injection of propofol. The use of lidocaine to prevent propofol injection pain is common. The analgesic effect of pre-injected lidocaine has been found to increase when a tourniquet is used.Objective: The aim of this study was to compare the effectiveness of various venous occlusion times with lidocaine analgesia to prevent pain during propofol injection.Methods: In this prospective, randomized, double-blind, controlled study, women aged 18 to 45 years, classifed as American Society of Anesthesiologists physical sta- tus I or II, who were scheduled to undergo elective surgery under general anesthesia induced with propofol, were randomly assigned to 1 of 5 groups: group 1, 2% lidocaine 20 mg in saline in a total volume of 10 mL and no venous occlusion; group 2, 2% lidocaine 20 mg in saline in a total volume of 10 mL plus venous occlusion for 15 seconds; group 3, 2% lidocaine plus venous occlusion for 30 seconds; group 4, 2% lidocaine plus venous occlusion for 60 seconds; and group 5, saline 10 mL and no venous occlusion. When the first 25% of the calculated propofol dose was administered, patients were asked about propofol-induced pain using a verbal pain scale (0 = no pain; 1 = mild pain; 2 = moderate pain; and 3 = severe pain). All patients and the anesthesiologist who evaluated pain severity were blinded to the study preparation being used.Results: The study comprised 100 women who were randomly divided into 5 groups of 20 patients each. Significantly more patients in group 5 (18 [90%] patients; P < 0.05) reported pain compared with the other treatment groups. In groups 2, 3, and 4, in which venous occlusion was applied, pain was reported during propofol injection in 6 (30%), 7 (35%), and 2 (10%) patients, respectively. The incidence of reported pain was significantly greater in group 1 (lidocaine without venous occlusion) than in group 4 (P < 0.05); however, the incidence of pain was similar in group 1 compared with groups 2 and 3.Conclusions: The present study found that pretreatment with lidocaine 20 mg with or without venous occlusion significantly reduced the incidence and the severity of pain during the injection of propofol when compared with the group with no venous occlusion administered saline. In addition, pretreatment with lidocaine 20 mg plus venous occlusion for 60 seconds significantly reduced the incidence of propofol-induced pain compared with lidocaine without venous occlusion.  相似文献   
92.
The proprotein convertases (PCs) are implicated in the activation of various precursor proteins that play an important role in tumor cell metastasis. Here, we report their involvement in the regulation of the metastatic potential of colorectal tumor cells. PC function in the human and murine colon carcinoma cell lines HT-29 and CT-26, respectively, was inhibited using siRNA targeting the PCs furin, PACE4, PC5, and PC7 or by overexpression of the general PC inhibitor alpha1-antitrypsin Portland (alpha1-PDX). We found that overexpression of alpha1-PDX and knockdown of furin expression inhibited processing of IGF-1 receptor and its subsequent activation by IGF-1 to induce IRS-1 and Akt phosphorylation, all important in colon carcinoma metastasis. These data suggest that the PC furin is a major IGF-1 receptor convertase. Expression of alpha1-PDX reduced the production of TNF-alpha and IL-1alpha by human colon carcinoma cells, and incubation of murine liver endothelial cells with conditioned media derived from these cells failed to induce tumor cell adhesion to activated murine endothelial cells, a critical step in metastatic invasion. Furthermore, colon carcinoma cells in which PC activity was inhibited by overexpression of alpha1-PDX when injected into the portal vein of mice showed a significantly reduced ability to form liver metastases. This suggests that inhibition of PCs is a potentially promising strategy for the prevention of colorectal liver metastasis.  相似文献   
93.
Duodenal duplication is a rare cause of acute pancreatitis in children. We report a case of acute pancreatitis in which abdominal sonography revealed an enlarged hypoechoic edematous pancreas with mildly dilated main pancreatic duct and a cystic structure with layered wall in the second part of duodenum. Abdominal CT yielded similar findings. The diagnosis of duodenal duplication was confirmed at surgery and subsequent histopathologic examination.  相似文献   
94.
95.
Metformin hydrochloride, which is better absorbed in the upper intestine, was formulated as a floating (buoyant) matrix tablet using a gas generating agent (sodium bicarbonate) and a gel forming hydrophilic polymer (hydroxypropyl methylcellulose). The formulation was optimized on the basis of floating ability and in vitro drug release. The resulting formulation produced robust tablets with optimum hardness, consistent weight uniformity and low tablet friability. All tablets but one exhibited satisfactory (gradual and near complete) drug release and buoyancy. In vitro drug release tests of these tablets indicated controlled sustained release of metformin hydrochloride and 96-99% released at the end of 8 h. Two formulations of fabricated tablets containing metformin hydrochloride (500 mg), sodium bicarbonate (75 mg), hydroxypropyl methylcellulose-K 4M (170-180 mg), citric acid (between 15 and 20 mg) and polyvinyl pyrrolidone K90 (32-40 mg) with hardness between 6.8 to 7.5 kg/cm2 showed a floating time of more than 8 h and promising drug release results. The release followed the Higuchi kinetic model, indicating diffusion dominated drug release.  相似文献   
96.
97.
A 10-year-old boy was admitted with a 4-month history of ataxic gait, headache, vomiting and diplopia. The headaches had worsened in month 4 and were associated with vomiting during head movement. Cranial computed tomography (CT) and magnetic resonance imaging (MRI) scans revealed a hydatid cyst located in the posterior fossa. The patient underwent suboccipital craniotomy and a cerebellar hydatid cyst (approximately 5 cm in diameter) was removed using Dowling's technique. The diagnosis was confirmed during surgery and by histological examination of a tissue sample from the cyst. The patient was treated with the antihelmintic agent albendazole in combination with antibiotics. The post-operative course was uneventful and the patient was discharged after 1 week. In conclusion, when a cystic lesion is detected on CT or MRI scans, hydatid disease should be taken into consideration in countries where hydatid infestation is endemic.  相似文献   
98.
99.
Cicek D  Kandi B  Demir B  Turgut D 《Skinmed》2007,6(6):298-301
A 23-year-old woman presented to our polyclinic complaining of itching, generalized dermatitis, and jaundice. She was in her 31st gestational week and had developed pruritus and the dermatitis since the first month of pregnancy; her jaundice started about a month before presentation. Her history included similar complaints in a previous pregnancy, which resulted in premature birth of a baby with a permanent brain defect. One of her sisters had had jaundice and itching in her 27th gestational week and delivered a healthy baby; a second sister had experienced itching and dermatitis in her second trimester and delivered a healthy baby. Physical examination of the patient showed that her eyes were jaundiced (Figure 1); skin examination revealed generalized erythematous excoriated papules, symmetrically distributed all over her body (Figure 2 Figure 3). Laboratory analyses revealed the following results: leukocyte count, 14.30/mm(3) (3.8-10.3/mm(3)); erythrocyte sedimentation rate, 25 mm/h (<20 mm/h); aspartate aminotransferase, 44 U/L (5-40 U/L); alanine aminotransferase, 63 U/L (5-40 U/L); lactate dehydrogenase, 1158 U/L (220-450 U/L); total bilirubin, 6.88 mg/dL (<1.10 mg/dL); and direct bilirubin, 3.27 mg/dL (<0.35 mg/dL). Urinalysis results were positive for bilirubin and urobilinogen. Positive serologic findings included rubella immunoglobulin G, 93 AU/mL (<15) and cytomegalovirus, 188 AU/mL (<10); negative findings included herpes simplex virus type 2 and hepatitis. Histopathologic examination of material collected from the left breast via punch biopsy showed parakeratosis, acanthosis, and perivascular lymphocyte infiltration in dermal vessels. Treatment with 2 g/d cholestyramine and a topical corticosteroid was effective in the patient, who was diagnosed with intrahepatic cholestasis of pregnancy and prurigo of pregnancy based on the clinical, histopathologic, and laboratory findings. To the authors' knowledge, this is the first such reported case in the literature.  相似文献   
100.
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