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   411篇
  免费   21篇
  国内免费   3篇
儿科学   30篇
妇产科学   12篇
基础医学   21篇
口腔科学   9篇
临床医学   33篇
内科学   87篇
皮肤病学   2篇
神经病学   4篇
特种医学   43篇
外科学   65篇
综合类   6篇
预防医学   94篇
眼科学   4篇
药学   9篇
中国医学   1篇
肿瘤学   15篇
  2022年   1篇
  2021年   2篇
  2020年   1篇
  2019年   1篇
  2018年   8篇
  2017年   3篇
  2016年   3篇
  2015年   4篇
  2014年   5篇
  2013年   9篇
  2012年   16篇
  2011年   12篇
  2010年   6篇
  2009年   9篇
  2008年   14篇
  2007年   9篇
  2006年   11篇
  2005年   9篇
  2004年   9篇
  2003年   10篇
  2002年   16篇
  2001年   13篇
  2000年   10篇
  1999年   12篇
  1998年   17篇
  1997年   13篇
  1996年   22篇
  1995年   19篇
  1994年   13篇
  1993年   12篇
  1992年   13篇
  1991年   20篇
  1990年   15篇
  1989年   17篇
  1988年   11篇
  1987年   8篇
  1986年   7篇
  1985年   4篇
  1984年   6篇
  1983年   3篇
  1982年   5篇
  1981年   10篇
  1980年   7篇
  1979年   5篇
  1978年   3篇
  1977年   7篇
  1976年   3篇
  1975年   2篇
排序方式: 共有435条查询结果,搜索用时 751 毫秒
1.
2.
Resting energy expenditure (REE) was measured in 68 patients with stable chronic obstructive pulmonary disease (COPD) and in 34 weight-stable, age-matched (65 +/- 8 y; means +/- SD) healthy control subjects. Fat-free mass (FFM) determined by bioelectrical resistance explained 84% of the variation in REE in the control group but only 34% in the COPD patients. REE could not reliably be predicted from regression equations either developed in healthy subjects or in COPD patients. REE adjusted for FFM was significantly higher (P less than 0.05) in weight-losing (n = 34) than in weight-stable (n = 34) patients (6851 +/- 781 and 6495 +/- 650 kJ/d, respectively). Pulmonary function was more compromised in weight-losing patients. Adjusted REE in weight-stable patients was significantly higher (P less than 0.01) than in the healthy control group (6131 +/- 405 kJ/d). In patients with COPD, factors in addition to FFM are important determinants of REE. A disease-related increase in REE develops, which may contribute to weight loss in COPD in combination with a lack of an adaptive response to undernutrition in weight-losing patients.  相似文献   
3.
4.
OBJECTIVE. To study the clinical outcome of anal dynamic graciloplasty (gracilis muscle transposition and implantation of electric stimulation device) in a consecutive series of 12 patients. DESIGN. Prospective study. SETTING. Maastricht University Hospital. PATIENTS AND METHODS. Twelve patients with incapacitating faecal incontinence were treated using anal dynamic graciloplasty because they were not amenable to other medical management. The data were analysed with emphasis on the clinical outcome, anal manometry, and gracilis muscle composition before and after electric stimulation. Results were considered significant if p < or = 0.05, using the paired Student's t-test. RESULTS. Eight patients achieved complete faecal continence, one patient still has a previously constructed colostomy and in three patients no faecal incontinence could be achieved, due to infections. Median follow-up is now over 18 months (range 16 weeks-5 years). Anal manometry demonstrated an anal pressure increased from 39 mmHg (without stimulation) to 66 mmHg with electric stimulation (mean increase 27 mmHg (CI: 19-35; n = 12, p < 0.01). Gracilis muscle composition showed an increase of type I relatively fatigue-resistant fibres, capable of prolonged contractions, from 45% before stimulation to 64% afterwards (mean increase 19% (CI: 14-21; n = 8, p < 0.01). CONCLUSION. Dynamic graciloplasty is capable of replacing the function of damaged or absent anal sphincters. The construction of a colostomy in patients with incapacitating faecal incontinence can be avoided.  相似文献   
5.
Small, patent cerebral aneurysms: atypical appearances at 1.5-T MR imaging   总被引:1,自引:0,他引:1  
Rolen  PB; Sze  G 《Radiology》1998,208(1):129
  相似文献   
6.
Multifrequency bio-electronic impedance analysis (MF BIA) measurements are taken from a heterogeneous group of patients, varying in size between obese and slim. The measuring system uses four electrodes: two current and two potential electrodes. Three new models are developed to calculate total body water (TBW) from the BIA data, and the resulting TBW values are compared with TBW determined by D2O dilution. The results demonstrate that the most simple model provides the best TBW values. For individual patients, TBW can be determined by means of bioimpedance measurement with an accuracy of 3 litres. In the most simple model (model 1), the body is electrically represented by a cylinder, and corrections are made for the amount of fat. This is an extension of the model used by Xitron. In the more advanced models (2 and 3), the body is represented by a cylinder for the trunk, and truncated cones represent the arms and legs. In model 2, ΔTBW amounts to 3 litres. It is shown that the resistance of the trunk is proportional to the square root of the length. In model 3, it is assumed that subcutaneous fat is a poor conductor if electric current. An equation is developed that describes the partition of subcutaneous fat, and the fat layer is then removed from the cones representing arms and legs and from the cylinder that models the trunk.  相似文献   
7.
Summary A case of ovarian Sertoli-Leydig cell tumour with a raised serum alpha fetoprotein in reported. The patient first presented at the age of 27 years with a history of 6 years' amenorrhoea followed by 3 months irregular vaginal bleeding. A ovarian tumour was found and excised and shown microscopically to be a spindle cell malignant tumour. The patient was treated with chemotherapy and had a complete response. Thirty months after first presentation there was a recurrence in the pelvis which microscopically showed the typical features of a Sertoli-Leydig cell tumour. Six months later a second recurrence had the microscopic appearance of a lipid cell tumour. A raised serum alpha fetoprotein was found at the time of the second recurrence and immunohistochemistry showed this protein in the Leydig and luteinized cells of the recurrent tumours but not in the spindle cells of the original ovarian neoplasm.  相似文献   
8.
The aim of the study was to determine the prevalence of antibodies to human papillomavirus (HPV) types 16, 18, 31, 33, and 45 in woman in Cape Town with cervical intraepithelial neoplasia (CIN) (n = 95), cervical cancer (n = 40), female blood donors (n = 95) and children (n = 110). The enzyme-linked immunosorbent assay (ELISA) made use of baculovirus synthesised HPV virus like particles (VLPs) as antigen. Antibodies to at least one HPV type were detected in sera from 75% of cancer patients, 71.6% of CIN patients, 44.2% of blood donors and 27.3% of children. Sera from 95 women with CIN were compared with age-matched female blood donors. There was a significant association of seropositivity to VLP-16 (P = 0.006) and VLP-45 (P = 0.008) with CIN compared with the blood donors. There was also a significant difference in the seropositivity of women with CIN to any of the five virus-like particle (VLP) types compared to the blood donors (P = 0.0002: OR = 3.2). Thirty-nine of sixty-nine (56.5%) women with CIN were found to be HPV-16 DNA positive. The average age of women in this group that were VLP-16 seropositive was 34 years and those found to be VLP-16 seronegative was 52 years of age. Antibodies to all five VLP types were detected in these populations, thus an ideal vaccine should induce protection from infection by a wide range of HPV types.  相似文献   
9.
Despite the high prevalence of cervical cancer and cervical neoplasias in South Africa, few studies have been performed in this region to establish which human papillomavirus (HPV) types are associated with the development of high-grade cervical intraepithelial neoplasia lesions and cervical cancer. To investigate these prevalence rates, punch biopsies were obtained from 56 women with cervical cancer and 141 women with histologically diagnosed cervical intraepithelial neoplasia 2 or 3 lesions. Nested polymerase chain reaction (PCR) using consensus degenerate PCR primers was performed for the detection of HPV DNA and HPV typing was done by restriction fragment length polymorphism. Forty-seven (94%) of the cervical cancer and 114 (88%) of the cervical intraepithelial neoplasia 2/3 biopsies were positive for HPV DNA. The prevalence rates of the HPV types detected in the cervical cancer biopsies were HPV 16 (82%), HPV 18, (10%), HPV 33 (10%), HPV 31 (2%), HPV 58 (2%), HPV 35 (2%), and HPV 59 (2%). The cervical intraepithelial neoplasia lesions contained HPV 16 (56.6%), HPV 33 (14%), HPV 31 (10.9%), HPV X (7%), HPV 52 (3.9), HPV 58 (3.1%), HPV 35 (2.3%), HPV 18 (1.6%), HPV 11 (0.8%). Five of the nine fragments that were not typed by the RFLP, designated HPV-X, were sequenced to give HPV6 (1/5), HPV 26 (2/5), HPV 68 (1/5), and candHPV 87 (1/5). HPV 58 was detected in one cervical cancer biopsy and four biopsies from cervical intraepithelial neoplasia grade 3 lesions and was shown to be a previously described variant [Williamson and Rybicki (1991) J. Med. Virol. 33:165-171]. In addition, a cervical intraepithelial neoplasia grade 2 lesion was shown to harbour HPV type HAN2294 (cand HPV 87). The results of this study indicate that cervical cancer and cervical intraepithelial neoplasia 2/3 are largely associated with HPV 16 infection in this group of South African women and, therefore, an effective HPV 16 based vaccine should prevent the development of cervical cancer in a large proportion of women from this region of South Africa.  相似文献   
10.
Several studies have attempted to define nutritional parameters that can be used to select malnourished hospitalised patients for nutritional support. A combination of objective nutritional parameters was evaluated in a group of 50 patients selected for total parenteral nutrition on clinical grounds only and compared with a control group. This control group consisted of 38 patients who were admitted for elective minor surgical procedures such as varicectomy and hernia repair. On a subset of 18 objective nutritional measurements, discriminant analysis was performed. In the evaluation it was shown that a combination of albumin (ALB), prealbumin (PALB), total lymphocyte count (TLC) and the percentage of ideal weight (PIW) was the most useful combination of nutritional tests in discriminating a chosen malnourished (M) group and a control group who were declared not malnourished (NM). With this combination the patients were correctly classified in 93% with a sensitivity of 93% and a specificity of 94%.  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