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   12058篇
  免费   481篇
  国内免费   73篇
耳鼻咽喉   65篇
儿科学   287篇
妇产科学   158篇
基础医学   1434篇
口腔科学   347篇
临床医学   617篇
内科学   2878篇
皮肤病学   191篇
神经病学   868篇
特种医学   548篇
外科学   2448篇
综合类   53篇
预防医学   382篇
眼科学   248篇
药学   698篇
中国医学   46篇
肿瘤学   1344篇
  2023年   58篇
  2022年   126篇
  2021年   207篇
  2020年   102篇
  2019年   133篇
  2018年   168篇
  2017年   132篇
  2016年   158篇
  2015年   192篇
  2014年   246篇
  2013年   295篇
  2012年   562篇
  2011年   602篇
  2010年   347篇
  2009年   340篇
  2008年   561篇
  2007年   657篇
  2006年   626篇
  2005年   686篇
  2004年   681篇
  2003年   666篇
  2002年   644篇
  2001年   360篇
  2000年   381篇
  1999年   324篇
  1998年   203篇
  1997年   179篇
  1996年   171篇
  1995年   130篇
  1994年   116篇
  1993年   132篇
  1992年   241篇
  1991年   199篇
  1990年   211篇
  1989年   227篇
  1988年   172篇
  1987年   156篇
  1986年   164篇
  1985年   160篇
  1984年   106篇
  1983年   100篇
  1982年   43篇
  1981年   40篇
  1980年   39篇
  1979年   59篇
  1978年   44篇
  1977年   52篇
  1972年   43篇
  1970年   42篇
  1968年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Intraoperative monitoring of anorectal pressure was used in a case of sacral lipomeningocele accompanied by congenital dermal sinus to protect the physiological function of the anorectal sphincters. This monitoring system consists of a manometric anorectal balloon and neural electrical stimulation. The system was able to differentiate functioning neural structures from surrounding tissues during the operation.  相似文献   
62.
63.
Abstract: We report a case of glucagonoma syndrome with liver metastasis, who responded completely to dacarbazine chemotherapy. A 77-year-old woman complained of itching skin eruptions (diagnosed as necrolytic migratory erythema) and weight loss. She was found to have glucose intolerance, anemia, hypoproteinemia and hyperglucagonemia. Abdominal CT and celiac arteriography showed a hypervascular tumor in the pancreatic tail and a metastatic tumor in the left hepatic lobe. Immunohistochemical examination of the metastatic liver tumor obtained by laparoscopic biopsy revealed the tumor cells to be positive for glucagon. The patient was treated with 20 courses of 300 mg/day intravenous dacarbazine for 5 consecutive days followed by a 4 week drug-free interval. No major side effects were noted. Treatment resulted in disappearance of the skin lesions and correction of anemia, glucose intolerance, hypoproteinemia and hyperglucagonemia. Follow-up abdominal CT showed complete resolution of both the primary pancreatic tumor and the metastatic liver tumor. We suggest that dacarbazine be considered as the treatment of choice for metastatic glucagonoma.  相似文献   
64.
Hepatic angiomyolipoma is a rare tumor composed of spindle-shaped and epithelioid smooth muscle cells, adipose tissue, and proliferating blood vessels. We report the first documented case of this tumor developing in a patient with ulcerative colitis. A solitary tumor (7.5×7.5×7cm) was detected in the left lateral segment of the liver and a left hepatic lobectomy was performed. The diagnosis of angiomyolipoma was confirmed by a pathological examination. We also review the literature on previously reported cases of hepatic angiomyolipoma.  相似文献   
65.
With regard to "acute kindling" that signifies progressive changes in various epileptiform discharges produced with repeated electrical stimulations in a brief time span in acute experiments, the interstimulation interval effect was examined. Kindling developments produced respectively with 3 and 30-minute interval stimulations to the visual cortex of rabbits were compared with each other. Eventually, in kindling with a longer interstimulation interval, after-discharges induced in every trial of stimulation were often lengthened in duration more prominently than those with the shorter interstimulation interval and, furthermore, occasional slight relapses in the afterdischarge duration occurred more infrequently in the former than in the latter. These results suggest that the interstimulation interval plays an important role in the development of acute kindling, presumably in relation to postictal inhibition. In addition, spontaneous interictal or ictal epileptiform discharges occasionally arising during the 3-minute interstimulation intervals were reported. These spontaneous discharges may suggest a high epileptogenicity in acute kindling.  相似文献   
66.
The relationship between the age and the spread of analgesia from different epidural anesthetic doses was examined by studying analgesic dose responses in cervical epidural analgesia. Two different anesthetic doses (5ml or 10ml) of 2% mepivacaine were injected into the cervical epidural space at a constant pressure (80mmHg) using an intravenous apparatus, and the spread of analgesia to pinprick was assessed. The significant correlation was found between the patients age and the number of spinal segments blocked (5ml:r = 0.8498, P < 0.01, 10ml:r = 0.5988, P < 0.01). The inverse linear relationship was found between the patients age and the segmental dose requirement (5ml:r = –0.6754, P < 0.01, 10ml:r = –0.5784, P < 0.01). Patients under 39 years of age showed a direct relationship between the dose injected and the number of spinal segments blocked, enabling prediction of the number of segments blocked with a given dose of local anesthetic. Doubling the epidural dose approximately doubled the number of spinal segments blocked. The analgesic dose-response relation in patients over 60 years of age differed from that in patients under 39 years of age and doubling the epidural dose did not double the number of spinal segments blocked. Progressively more extensive analgesia was obtained from a given dose of local anesthetic with advancing age. It was difficult to limit the extent of analgesia by injecting a smaller dose of local anaesthetic in the elderly.(Hirabayashi Y, Matsuda I, Inoue S et al.: Analgesic dose-response relation in cervical epidural block. J Anesth 2: 22–27, 1988)  相似文献   
67.
The immune response to a naked plasmid DNA encoding the nucleoprotein (N protein) of porcine transmissible gastroenteritis virus (TGEV) was investigated in this study. A complementary DNA of the entire N gene was amplified by RT-PCR, and inserted into a mammalian expression vector (pcDNA3.1) to construct a recombinant plasmid (pcDNA/N). To evaluate the immunogenicity of the construct, BALB/c mice were intramuscularly immunized with different doses (50, 100 and 200 μg/mouse) of pcDNA/N twice at a 5-week interval. An optimal antibody response was achieved with 100 μg of pcDNA/N. The response lasted at least 11 weeks after primary immunization. By western blotting analysis, the antibodies specifically recognized a 47 kDa protein corresponding to the viral N protein, but they did not reveal neutralizing activity against infectious TGEV in vitro. Immunoglobulin G2a was predominant among these antibodies, which was indicative of Th1 type cell activation in pcDNA/N immunized mice. Moreover, spleen cells from these mice showed stronger immune responses than those from live vaccine or parental vector immunized mice. These results suggest that the construct can elicit both humoral and cell-mediated immune (CMI) responses against TGEV N protein in mice.  相似文献   
68.
T-Cell Regulation in Autoimmune Thyroiditis   总被引:12,自引:0,他引:12  
  相似文献   
69.
 The recently identified prostate cancer susceptibility gene ELAC2 (HPC2) harbors two common missense variants, a serine to leucine substitution at residue 217 (Leu217) and an alanine to threonine substitution at residue 541 (Thr541). We genotyped the two variants in a Japanese cohort consisting of 350 prostate cancer patients 242 male population controls, and 114 male low-risk controls. Both missense alleles, Leu217 and Thr541, were carried at higher frequency in Japanese patients than in the controls (Leu217, P = 0.0012; Thr541, P = 0.0145), and the odds ratios associated with carrying these sequence variants were higher in Japanese than in Caucasians. Although the Leu217 and Thr541 variants of ELAC2 are less common in Japanese than in Caucasians, both variants confer significantly increased risk of prostate cancer in Japanese. Carriage of these variants was not associated with age at diagnosis, tumor stage, or tumor grade in these Japanese prostate cancer patients. The allele-specific pattern of risk observed in Japanese and familial Caucasian patients was qualitatively similar; however, the magnitude of that risk was considerably greater in Japanese than in Caucasians. Received: September 3, 2002 / Accepted: October 2, 2002  相似文献   
70.
Human endometrial stromal cells (ESC) can produce a variety of chemokines, especially after inflammatory stimulation. Interferon-gamma-inducible protein-10 (IP-10) is a potent chemoattractant for lymphocytes, and belongs to the family of non-ELR CXC chemokines. The expression of IP-10 in ESC after stimulation with interferon-gamma (IFN-gamma), interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha), or lipopolysaccharide (LPS) was evaluated using an enzyme-linked immunosorbent assay and Northern blot analysis. A small amount of IP-10 protein was detected in the culture media of unstimulated ESC. The expression of IP-10 mRNA was detected in ESC. IFN-gamma, IL-1 beta, TNF-alpha and LPS significantly stimulated the expression of IP-10 mRNA and protein in ESC. These results suggest that the production of IP-10 by ESC is regulated by inflammatory mediators. The modulation of IP-10 concentrations in the local environment may contribute to the normal and pathological processes of human reproduction by regulating leukocyte trafficking in the endometrium.  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