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   18507篇
  免费   897篇
  国内免费   119篇
耳鼻咽喉   364篇
儿科学   356篇
妇产科学   310篇
基础医学   2787篇
口腔科学   379篇
临床医学   1113篇
内科学   4551篇
皮肤病学   314篇
神经病学   1471篇
特种医学   719篇
外国民族医学   1篇
外科学   3063篇
综合类   91篇
一般理论   1篇
预防医学   496篇
眼科学   220篇
药学   1223篇
中国医学   59篇
肿瘤学   2005篇
  2023年   81篇
  2022年   187篇
  2021年   339篇
  2020年   173篇
  2019年   224篇
  2018年   289篇
  2017年   239篇
  2016年   253篇
  2015年   274篇
  2014年   425篇
  2013年   488篇
  2012年   879篇
  2011年   1027篇
  2010年   596篇
  2009年   518篇
  2008年   854篇
  2007年   968篇
  2006年   979篇
  2005年   972篇
  2004年   1056篇
  2003年   940篇
  2002年   1077篇
  2001年   551篇
  2000年   555篇
  1999年   511篇
  1998年   270篇
  1997年   235篇
  1996年   215篇
  1995年   158篇
  1994年   169篇
  1993年   184篇
  1992年   391篇
  1991年   346篇
  1990年   351篇
  1989年   322篇
  1988年   289篇
  1987年   270篇
  1986年   242篇
  1985年   227篇
  1984年   178篇
  1983年   133篇
  1982年   79篇
  1981年   67篇
  1980年   75篇
  1979年   90篇
  1978年   85篇
  1977年   85篇
  1974年   67篇
  1972年   64篇
  1968年   63篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
81.
We report a case of para-adrenal angiofollicular lymph node hyperplasia (Castleman's disease) of the hyaline-vascular type. The mass could not be differentiated from an adrenal tumor by ultrasonography and computed axial tomography (CT). However, magnetic resonance imaging (MRI) suggested the possibility of an extra-adrenal origin of the mass. The intensity of the mass by MRI was homogeneous and of a higher intensity in the T2-weighted image than in the T1-weighted image, a finding similar to lymphadenopathy, lymphatic tumorous mass or metastatic tumor of the lymph node. Ultrasonography, CT and MRI may not be useful in characterizing Castleman's disease, but MRI was useful to distinguish asymptomatic para-adrenal masses from those of adrenal origin.  相似文献   
82.
Sixty-nine strains of Vibrio cholerae O1 isolated at different times were analysed to investigate if there were any differences among the O1 strains isolated before, during and after the advent of the O139 serogroup. Of the 69 O1 strains examined, 68 belonged to the Ogawa serotype while one belonged to the Inaba serotype. With the exception of one strain all other strains of V. cholerae O1 belonged to the eltor biotype. A single O1 strain isolated before the emergence of the O139 serogroup could not be classified as either eltor or classical biotype because it was resistant to both classical and eltor specific bacteriophages. Marked variations in the susceptibility to antibiotics of V. cholerae O1 isolated during the different periods were observed. In addition, strains of V. cholerae isolated after the epidemic of serogroup O139 in Calcutta showed an expanding R-type with resistance to a variety of drugs as compared to the O1 strains isolated before the advent of the O139 serogroup. From this study, it is clear that there is a substantial mobility in genetic elements of V. cholerae O1 which necessitates a continuous monitoring to keep abreast of the changing traits of the etiologic agent of cholera.  相似文献   
83.
Summary To study the effects of family history and reproductive, anthropometric, and dietary factors on the risk of breast cancer among low risk populations, we conducted a hospital-based case-control study involving 908 patients with breast cancer and their matched controls, in Japan. A positive family history of breast cancer significantly increased the risk of breast cancer (odds ratio = 1.52, 95% confidence interval: 1.14–2.03). The risk further increased with increasing number of family members affected. Obesity, single marital status, fewer births, a late childbirth, and less consumption of green-yellow vegetables and dairy products were also associated with an increased risk of breast cancer. These associations were independent in multivariate analyses. There was no increase in risk associated with consumption of high fat foods. When analyzed by menopausal status, the association with family history of breast cancer, especially in the first degree of relatives, was more evident for premenopausal breast cancer. The associations with obesity and lower consumption of dairy products were more pronounced for postmenopausal breast cancer, while those with lower parity and single marital status were stronger for premenopausal breast cancer.  相似文献   
84.
A 23-year-old woman had lower abdominal pain, diarrhea and bloody stool was admitted and given a diagnosis of influenza B. Her home doctor had started treatment by neuraminidase inhibitor (oseltamivir) the previous day. Colonoscopic examination revealed an area of hemorrhage and erosion in the left transverse colon. After halting oseltamivir treatment these symptoms disappeared and her colonoscopic findings improved. A drug-induced lymphocyte stimulation test was positive for oseltamivir. This case is the first reported case of acute hemorrhagic colitis induced by oseltamivir.  相似文献   
85.
We performed laparoscopic appendectomy and drainage to treat panperitonitis due to perforated appendicitis that occurred in a 28‐year‐old woman. We believe this is an appropriate procedure to treat perforated appendicitis because it is safe and minimally invasive, and faster recovery can be expected than after conventional open appendectomy.  相似文献   
86.
BACKGROUND: Haemophilus influenzae (H. influenzae) is the most frequent bacterial pathogen of respiratory tract infections in children. Detection of antimicrobial susceptibility of H. influenzae is necessary for institution of appropriate antibiotic treatments. METHODS: A total of 281 strains of H. influenzae isolated from sputum samples of 281 pediatric patients with respiratory tract infections were recruited for study. Antibiotic susceptibility was determined by assessing minimum inhibitory concentrations (MIC) of antimicrobial agents. MIC were measured by utility of Agar dilution susceptibility test. RESULTS: Of the total, 38 (13.5%) strains produced beta-lactamase (BLP), 56 (19.9%) strains were beta-lactamase non-producing, ampicillin resistant (BLNAR). The overall resistant proportion to ampicillin was 33.4%. The data indicated that sulbactam/ampicillin, cefotaxime, ceftriaxone and cefditoren are effective against BLP strains. In addition, a high prevalence of BLNAR H. influenzae strains was identified, with an overall isolation rate of 19.9%. Those strains mainly demonstrated intermediate level to ampicillin (ampicillin-MIC 相似文献   
87.
88.
Summary The CT, MR and histological features of a rare ganglioneuroblastoma of the cerebellopontine angle and cavernous sinus are reported.  相似文献   
89.
Shionogi carcinoma 115 (SC115), an androgen-dependent mouse mammary tumor, rapidly loses its androgen responsiveness after androgen withdrawal. The growth of this tumor can also be stimulated by high doses of estrogen or glucocorticoid. In the present study, the maintenance of hormone-responsive growth of SC115 tumors with a high dose of estrogen was examined in castrated male mice using an SCI 15 subline obtained by serial transplantations of SCI 15 tumors in estrogen-treated castrated mice for 3 years (30 generations) (subline E2). Seed tumors from both SC115 and subline E2 could rapidly grow in castrated mice given daily injections of testosterone propionate (TP), 17β-estradiol (E2), or dexamethasone (Dex) (100 μg/mouse/day) but not in those given vehicle alone. Although SCI 15 and subline-E2 tumors grown with TP or Dex showed temporary regression after steroid withdrawal, the tumors grown with E2 did not show such temporary regression. The TP-, E2-, or Dex-induced growth of subline-E2 tumors was almost the same as that of the original SCI 15 tumors. However, responsiveness to androgen, estrogen or glucocorticoid of both tumors disappeared within one passage in steroid-depleted castrated mice. The present findings demonstrate that the loss of responsiveness to androgen as well as to high doses of estrogen or glucocorticoid of SCI 15 tumors can be prevented in castrated mice not only with androgen but also with high doses of estrogen.  相似文献   
90.
Hypertrophic scars (HS) are a consequence of abnormal wound healing. We examined fatty acids that are contained within, and participate in, every reaction through the membrane; then, we analyzed the percentage composition of the fatty acids in deepithelialized normal dermis (ND) and HS. In vivo HS samples were obtained from six patients undergoing surgical excision, and ND samples from five patients undergoing skin grafting surgery for excess. In vitro, cultured fibroblasts from HS and ND were also analyzed. The percentage composition of fatty acids extracted from all the samples was analyzed. In vivo, arachidonic acid (20:4) was significantly more abundant in HS than in ND, in the phospholipids from both whole tissue and cell membranes. In vitro, there were no significant differences among ND, HS, and 10% fetal calf serum. The results suggest that HS formation does not necessarily involve simple excess of 20:4; however, there are considerable differences in the percentage composition of 20:4 between ND and HS. Arachidonic acid probably participates in the formation and maintenance of HS, whereas in vitro cultured fibroblasts are affected largely by fetal calf serum.  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