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   577篇
  免费   38篇
  国内免费   7篇
儿科学   5篇
妇产科学   7篇
基础医学   75篇
口腔科学   11篇
临床医学   36篇
内科学   87篇
皮肤病学   1篇
神经病学   62篇
特种医学   21篇
外科学   145篇
综合类   2篇
一般理论   1篇
预防医学   56篇
眼科学   5篇
药学   22篇
肿瘤学   86篇
  2023年   3篇
  2021年   5篇
  2020年   6篇
  2019年   9篇
  2018年   13篇
  2017年   10篇
  2016年   13篇
  2015年   12篇
  2014年   22篇
  2013年   27篇
  2012年   42篇
  2011年   33篇
  2010年   26篇
  2009年   11篇
  2008年   26篇
  2007年   33篇
  2006年   32篇
  2005年   26篇
  2004年   24篇
  2003年   15篇
  2002年   18篇
  2001年   15篇
  2000年   15篇
  1999年   17篇
  1998年   8篇
  1997年   7篇
  1996年   9篇
  1995年   4篇
  1994年   9篇
  1993年   10篇
  1992年   14篇
  1991年   10篇
  1990年   9篇
  1989年   10篇
  1988年   10篇
  1987年   14篇
  1986年   14篇
  1985年   11篇
  1984年   3篇
  1983年   3篇
  1982年   1篇
  1981年   5篇
  1980年   2篇
  1979年   4篇
  1978年   1篇
  1977年   3篇
  1976年   2篇
  1974年   1篇
  1973年   2篇
  1970年   2篇
排序方式: 共有622条查询结果,搜索用时 31 毫秒
1.
Cohen syndrome: fertility in a female patient   总被引:1,自引:0,他引:1  
In this report we describe fertility in an adult female with Cohen syndrome. She gave birth to a son, now 1.5 years old, with discrete facial stigmata and slight psychomotor retardation.  相似文献   
2.
K1K2Pu, a recombinant t-PA/u-PA chimera with increased thrombolytic potency in animal models of venous and arterial thrombosis, which consists of amino acids 1 to 3 and 87 to 274 of human tissue-type plasminogen activator (t-PA) and amino acids 138 to 411 of human single chain urokinase-type plasminogen activator (scu-PA), was produced and conditioned for use in patients. Chinese hamster ovary cells were transfected with an expression plasmid containing the K1K2Pu cDNA, high producer cell lines were selected and scaled up in 800 cm2 roller bottles, and 350 ml conditioned cell culture medium was harvested 3 to 7 times at 2 to 5 day intervals. Batches of 21 +/- 4 liter (mean +/- SD, n = 28) containing 1.8 +/- 0.6 mg/l of K1K2Pu related antigen were purified by chromatography on Copper chelate-Sepharose and immunoadsorption on an insolubilized murine monoclonal antibody (MA-1C8). Yields were 8.6 +/- 3.4 mg K1K2Pu per batch with a specific activity of 83,000 +/- 44,000 IU/mg. The final material, obtained at a concentration of approximately 0.7 mg/ml, was dialyzed against 0.3 M NaCl, 0.02 M Tris-HCl buffer, pH 7.5, containing 0.01% Tween 80 and 10 KIU/ml aprotinin. It was homogeneous on SDS-PAGE, contained 6.5 +/- 6.9 percent two chain material and the contamination with murine monoclonal antibody was less than 0.1 percent. After filtration of pools of 3 to 5 selected batches on 0.22 microns Millipore filters the material was sterile and virus free by routine screening; it was obtained at a concentration of approximately 0.5 mg/ml with a specific activity of 110,000 +/- 16,000 IU/mg (mean +/- SD, n = 3) and an endotoxin content of 0.5 to 7 units/mg. Bolus injection at a dose of 1 mg/kg in mice did not produce weight loss within 8 days. Thus, this material appears to be suitable for the investigation on a pilot scale of the pharmacokinetic and thrombolytic properties of K1K2Pu in patients with thromboembolic disease.  相似文献   
3.
This paper describes 29 patients with Ewing's sarcoma of bone treated between 1975 and 1990 at the University of Nijmegen Hospital, Nijmegen, The Netherlands. Osteomyelitis was the primary diagnosis in 24%. Treatment consisted of chemotherapy in combination with surgery and/or radiotherapy. Nine patients received radiotherapy only; five of them died of disease. Five patients underwent an intralesional excision; four of them died of disease. Twelve patients underwent a wide excision; there is no evidence of disease in any of them. Three patients underwent a radical disarticulation; all died of disease. The disease-free survival at 1.5 years was 66%. This figure at 5 years was 55%. After wide excision and reconstruction in tumors of expendable, femoral or radial bones good functional results were obtained in all cases. © 1995 Wiley-Liss, Inc.  相似文献   
4.
PAX6 is a candidate gene for familial aniridia. We have carried out a mutational analysis of the PAX6 gene in a three-generation family from Germany, containing 5 individuals affected with ocular abnormalities. In all affected individuals, a heterozygous mutation was detected in the PAX6 gene, exchanging tyrosine 369 by a stop codon. The mutation is located in the 3' moiety of the PST domain, at the C terminus of the PAX6 protein. In the affected family members, the same heterozygous mutation leads to distinct phenotypes of varying severity. Most notably, no aniridia was observed in one of the family members carrying the mutation, although other ocular abnormalities (underdeveloped iris and cataracts) were present. We discuss the possibility that small C terminal truncations of the PAX6 protein might lead to less severe or more divergent phenotypes than trancations at internal positions.  相似文献   
5.
6.
In this study we investigated the mechanism of enhanced resistance against Listeria monocytogenes induced with Listeria ribosomal RNA and the adjuvant dimethyldioctadecylammonium bromide (DDA). Mice immunized with DDA alone (which were not protected against Listeria-infection) were used as negative controls. Mice immunized with RNA plus DDA were found to have an increased capacity to mobilize polymorphonuclear leukocytes (PMNs) and macrophages to the inflamed peritoneal cavity compared to mice immunized with adjuvant alone. Intraperitoneal (i.p.) inflammation was induced by injection of the sterile irritant proteose peptone. The protective capacity of various cell-populations was investigated by i.p. transfer of cells to normal recipient mice and concomitant challenge of recipient animals with a lethal dose of viable Listeria. Inflammatory PMNs as well as inflammatory macrophages from mice immunized with RNA plus DDA protected recipient animals against listeriosis whereas cells from mice immunized with DDA alone failed to do so. Therefore, enhanced mobilization as well as activation of PMNs and macrophages may have contributed to the expression of protection against L. monocytogenes induced with RNA plus DNA.  相似文献   
7.
8.
Luc L 《Obesity surgery》1993,3(2):179-180
During the past 7 years, 170 morbidly obese patients have been subjected to a biliopancreatic diversion. Mean weight loss achieved over 2 years was greater than 70% of excess weight and was maintained. Early complications were rare. The most common side-effects are discussed. The re-operation rate because of these side-effects was 7%. Eating normal meals, together with a stable weight loss, has provided these patients with a better quality of life.  相似文献   
9.

Background

Self-efficacy beliefs are an important determinant of (changes in) health behaviors. In the area of smoking cessation, there is a need for a short, feasible, and validated questionnaire measuring self-efficacy beliefs regarding smoking cessation.

Purpose

The purpose of this study is to investigate the psychometric properties of a six-item questionnaire to assess smoking cessation self-efficacy.

Methods

We used longitudinal data from a smoking cessation study. A total of 513 smokers completed the Smoking Abstinence Self-efficacy Questionnaire (SASEQ) and questionnaires assessing depressive symptoms and motivation to quit smoking. After that, they set a quit date and attempted to stop smoking. One year after the quit date, smoking status of participants was assessed by self report. The psychometric properties of the SASEQ were studied and we investigated whether SASEQ scores predicted successful smoking cessation.

Results

Factor analysis yielded one factor, with an Eigenvalue of 3.83, explaining 64% of variance. All factor loadings were ≥0.73. We found a Cronbach’s alpha of 0.89 for the SASEQ, low correlations for the SASEQ with depressive symptoms, and motivation to quit, indicating that self-efficacy is measured independently of these concepts. Furthermore, high baseline SASEQ scores significantly predicted smoking abstinence at 52 weeks after the quit date (OR?=?1.85; 95% CI?=?1.20~2.84).

Conclusions

The SASEQ appeared to be a short, reliable, and valid questionnaire to assess self-efficacy beliefs regarding smoking abstinence. In the present study, this instrument also had good predictive validity. The short SASEQ can easily be used in busy clinical practice to guide smoking cessation interventions.  相似文献   
10.
Context:Epidemiologically, an inverse relationship between body mass index (BMI) and sleep duration is observed. Intra-individual variance in the amount of slow wave sleep (SWS) or rapid eye movement (REM) sleep has been related to variance of metabolic and endocrine parameters, which are risk factors for the disturbance of energy balance (EB).Objective:To investigate inter-individual relationships between EB (EB=∣energy intake-energy expenditure∣, MJ/24?h), SWS or REM sleep, and relevant parameters in normal-weight men during two 48?h stays in the controlled environment of a respiration chamber.Subjects and methods:A total of 16 men (age 23±3.7 years, BMI 23.9±1.9?kg?m(-2)) stayed in the respiration chamber twice for 48?h to assure EB. Electroencephalography was used to monitor sleep (2330-0730 hrs). Hunger and fullness were scored by visual analog scales; mood was determined by State Trait Anxiety Index-state and food reward by liking and wanting. Baseline blood and salivary samples were collected before breakfast. Subjects were fed in EB, except for the last dinner, when energy intake was ad libitum.Results:The subjects slept on average 441.8±49?min per night, and showed high within-subject reliability for the amount of SWS and REM sleep. Linear regression analyses showed that EB was inversely related to the amount of SWS (r=-0.43, P<0.03), and positively related to the amount of REM sleep (r=0.40, P<0.05). Relevant parameters such as hunger, reward, stress and orexigenic hormone concentrations were related to overeating, as well as to the amount of SWS and REM sleep, however, after inclusion of these parameters in a multiple regression, the amount of SWS and REM sleep did not add to the explained variance of EB, which suggests that due to their individual associations, these EB parameters are mediator variables.Conclusion:A positive EB due to overeating, was explained by a smaller amount of SWS and higher amount of REM sleep, mediated by hunger, fullness, State Trait Anxiety Index-state scores, glucose/insulin ratio, and ghrelin and cortisol concentrations.  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