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   1721篇
  免费   50篇
  国内免费   75篇
耳鼻咽喉   2篇
儿科学   111篇
妇产科学   20篇
基础医学   165篇
口腔科学   15篇
临床医学   182篇
内科学   431篇
皮肤病学   49篇
神经病学   77篇
特种医学   329篇
外科学   116篇
综合类   28篇
预防医学   63篇
眼科学   34篇
药学   109篇
中国医学   5篇
肿瘤学   110篇
  2020年   12篇
  2018年   16篇
  2016年   11篇
  2015年   20篇
  2014年   27篇
  2013年   35篇
  2012年   40篇
  2011年   52篇
  2010年   47篇
  2009年   67篇
  2008年   38篇
  2007年   71篇
  2006年   38篇
  2005年   48篇
  2004年   27篇
  2003年   33篇
  2002年   27篇
  2001年   32篇
  2000年   50篇
  1999年   26篇
  1998年   90篇
  1997年   79篇
  1996年   71篇
  1995年   56篇
  1994年   48篇
  1993年   51篇
  1992年   34篇
  1991年   34篇
  1990年   34篇
  1989年   50篇
  1988年   59篇
  1987年   43篇
  1986年   37篇
  1985年   39篇
  1984年   30篇
  1983年   30篇
  1982年   22篇
  1981年   17篇
  1980年   23篇
  1979年   20篇
  1978年   16篇
  1977年   29篇
  1976年   16篇
  1975年   22篇
  1974年   22篇
  1973年   23篇
  1972年   25篇
  1971年   15篇
  1970年   13篇
  1968年   11篇
排序方式: 共有1846条查询结果,搜索用时 31 毫秒
81.
Background Hailey‐Hailey disease (HHD) or familial benign chronic pemphigus is a rare autosomal dominant inherited skin disorder, characterized by flaccid vesicles and erosions on the intertriginous areas. Current treatments are not particularly effective. We report 6 cases dramatically improving with doxycycline. Case reports 6 patients, aged from 33 to 77 years old, presented with a variable 4 to 40 year history of severe treatment‐resistant HHD. All 6 patients were then treated successfully with doxycycline 100 mg per day for at least 3 months. Discussion An improvement was observed in all 6 patients from 1 week to 3 months after the beginning of treatment. Relapses were observed after various periods. Maintenance half‐dose therapy seemed to be beneficial in patients experiencing recurrence. Only one patient developed gastro‐intestinal intolerance. No other side effects were reported. Currently, 2 patients have improved and present a decreased number of exacerbations, 2 others are in complete remission after more than 5 years of follow‐up. Treatment efficiency is difficult to evaluate in HHD as it is a rare condition. No controlled studies have been published. Local treatments may improve inflammation but do not treat the underlying cause, targeted systemic therapies exist but there is little evidence supporting their use, physical treatments are cumbersome. Besides their antibiotic potential, tetracycline antibiotics also have anti‐inflammatory properties and anticollagenase activity via inhibition of matrix metalloproteinases. Conclusions Doxycycline appears to be an interesting therapeutic option in Hailey‐Hailey disease.  相似文献   
82.
Background Post‐inflammatory hyperpigmentation (PIH) is a common occurrence in patients with acne vulgaris, particularly in those with skin of colour. Aims A previous study has demonstrated the benefit of tretinoin (retinoic acid) in the treatment of PIH; however, there is currently no standard protocol to evaluate change in PIH following treatment. Based on these findings, we performed a pilot, exploratory, blinded, intraindividual‐controlled methodology study that consisted of a photographic assessment protocol with facial mapping. Materials and methods The study was based on a secondary analysis of a phase 4, community‐based trial of 544 acne patients who were treated with tretinoin gel microsphere 0.04% or 0.1%. Only patients with Fitzpatrick types III–V (skin of colour) were included in the study; subjects with Fitzpatrick skin type VI were excluded because the photographic assessment did not allow for proper evaluation. Results Despite the small number of subjects evaluated (n = 25), the results revealed consistent assessment of improvement in PIH between two independent graders (weighted κ = 0.84). Conclusion Further study with a larger population is recommended to validate the accuracy of this method.  相似文献   
83.
Background Bedbugs (Cimex lectularius) have been feeding on sleeping human beings since prehistory. In Europe, bed bugs were common and endemic until World War II when improved body and home hygiene, and widespread use of insecticides led to almost complete eradication. Current evidence indicates that bedbugs are making a comeback in Europe, USA, Canada and Australia. In our practice in Southern France, we observed several cases within a period of only 1 year. Objectives Based on this experience, we conducted an epidemiological study to evaluate the status of bedbugs in France. Methods During summer 2009, we mailed a short questionnaire to all hospital professors in the CEDEF (Collège des Enseignants de Dermatologie de France) asking four questions: number of suspected diagnosis of bedbugs in the year 2009, and number of certain positive diagnosis, difficulties in treatment, use of a pest control professional for treatment, and finally personal opinion on actual incidence of bedbugs, compared with past years. Results Of the 84 questionnaires sent, there were only 26 responses despite two reminders. The responses were predominantly southern France, probably as a result of intensive immigration and increased travel and trade. Difficulties encountered during diagnosis and treatment are also mentioned. Utilizing the services of entomological experts and pest control professionals is essential. Conclusions France has the same experience regarding the resurgence of bedbugs as several European countries, USA, Canada and Australia, especially the southern regions. This emerging health problem has to be known by dermatologists. A national programme has been launched in France to assess actual incidence and study C. lectularius‐ related diseases.  相似文献   
84.
85.
86.
Phosphoinositide-specific phospholipase C (PLC) is a key enzyme in the regulation of Ca(2+) release from inositol 1,4,5-triphosphate-sensitive stores. U73122 (1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione) has been extensively used as a pharmacological inhibitor of PLC to elucidate the importance of this enzyme family in signal transduction pathways. U73122 has an electrophilic maleimide group, which readily reacts with nucleophiles such as thiols and amines. In the current study the conjugation of U73122 to common components of cell culture medium, namely l-glutamine, glutathione, and bovine serum albumin (BSA), was demonstrated. The half-life of U73122 on incubation with phosphate-buffered saline (PBS), Hanks' buffered saline solution (with 2 mM glutamine), optimized basal nutrient medium (MCDB131, without BSA), complete medium, Dulbecco's modified Eagle's medium (with 2 mM l-glutamine) was approximately 150, 60, 32, 30, and 18 min, respectively. However, U73122 was not recoverable from medium supplemented with 0.5% BSA. U73122 underwent hydrolysis of the maleimide group when incubated with PBS. Glutamine conjugates of U73122 were identified in cell culture medium. Furthermore, the inhibition of epidermal growth factor-stimulated Ca(2+) release in a human epidermoid carcinoma cell line (A431) by U73122 was substantially reduced by the presence of BSA in a time-dependent manner. In complex cellular assays, the availability of U73122 to inhibit PLC may be limited by its chemical reactivity and lead to the misinterpretation of results in pharmacological assays.  相似文献   
87.
Somatomedin C/IGF I, dehydroepiandrosterone sulfate (DHAS), testosterone (T) or estradiol (E2) have been measured in 154 patients of a previous study in which growth hormone (GH) responses to classical pharmacologic stimuli and spontaneous growth hormone secretion during sleep were compared in short children before and at the beginning of puberty. Five groups were identified: Group I, normal growth hormone secreting children; group II, completely growth hormone deficient; group III, partially growth hormone deficient; group IV, with normal sleep secretion and low responses to stimuli; group V, with the reverse situation. The somatomedin C/IGF I levels were widely dispersed. In group I, the mean +/- SEM levels of somatomedin C/IGF I were 0.77 +/- 0.047 U/ml before puberty and 1.36 +/- 0.142 U/ml in early pubertal patients, with a relation to age (r = 0.52, p less than 0.001). The difference between prepubertal and pubertal patients was significant. In groups II to V, there was no pubertal rise of somatomedin C/IGF I. In group II, the mean IGF I level was 0.48 +/- 0.05 U/ml, significantly lower than in prepubertal patients of group I. In groups III, IV and V, it was 0.7 +/- 0.069 U/ml, 0.8 +/- 0.059 U/ml, and 0.73 +/- 0.059 U/ml respectively, not different from prepubertal patients of group I, but significantly lower than in early pubertal patients of the same group. In prepubertal patients, somatomedin C/IGF I was slightly but highly significantly correlated to growth hormone sleep secretion (r = 0.27, p less than 0.001) and to dehydroepiandrosterone sulfate (r = 0.36, p less than 0.001), but growth hormone and dehydroepiandrosterone sulfate were not correlated with each other.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
88.
JM216 (bis-acetato ammine dichloro cyclohexylamine Pt IV) is an oral platinum complex presently undergoing phase II clinical trials. Previous studies have identified some of its biotransformation products in clinical materials. This study evaluated the nature of JM216 biotransformation products intracellularly in two different human ovarian carcinoma cell lines, one relatively sensitive to platinum agents (CH1: JM216 4 h IC50 of 5.8 microM) and the other relatively resistant (SKOV3: JM216 4 h IC50 of 60.7 microM). Metabolic profiles were also evaluated at different growth status and in cells pretreated with buthionine sulphoximine (BSO), an agent known to decrease intracellular glutathione levels. Results showed that JM216 enters the cells and that the nature and percentage of biotransformation products was dependent upon glutathione levels. Furthermore, results support the view that the previously reported peak A biotransformation product contains a glutathione adduct. In exponentially growing SKOV3 cells which contain higher glutathione levels than CH1, (82.5 vs 37.8 nmol mg-1 protein), peak A represented 89% of total platinum 4 h after JM216 exposure compared with only 24% in CH1. Moreover, 60-70% depletion of glutathione achieved by 24 h pretreatment of cells with BSO resulted in a significant decrease in peak A in both cell lines and increased the cytotoxicity of JM216 in both CH1 and SKOV3 by approximately 2-fold. Following a 4 h exposure of exponentially growing SKOV3 cells to JM216, only peak A (89%) and JM216 (11%) could be detected whereas in CH1 cells, peak A (24%), JM216 (73%) and JM118 [cis-ammine dichloro (cyclohexylamine) platinum II] (3%) were detected. However, in CH1 cells at confluence, where glutathione is lower (8 nmol mg-1 protein) four metabolites (plus JM216 itself) were detected following exposure to 50 microM JM216; peak A, JM118, JM383 (bis-acetato ammine (cyclohexylamine) dihydroxy platinum IV) and an unidentified metabolite (D), also observed in patient''s plasma ultrafiltrate. In confluent SKOV3 cells exposed to 50 microM JM216, peak A, JM216 and JM118 were detected. A further unidentified metabolite observed in patients receiving JM216 (metabolite F) was not formed inside these tumour cells. Overall, these data suggest that glutathione conjugation represents a major deactivation pathway for JM216.  相似文献   
89.
90.
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