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   3883篇
  免费   330篇
  国内免费   7篇
耳鼻咽喉   16篇
儿科学   153篇
妇产科学   167篇
基础医学   551篇
口腔科学   40篇
临床医学   461篇
内科学   676篇
皮肤病学   66篇
神经病学   377篇
特种医学   79篇
外科学   447篇
综合类   70篇
一般理论   6篇
预防医学   580篇
眼科学   34篇
药学   238篇
中国医学   4篇
肿瘤学   255篇
  2023年   51篇
  2022年   58篇
  2021年   114篇
  2020年   70篇
  2019年   109篇
  2018年   118篇
  2017年   98篇
  2016年   89篇
  2015年   105篇
  2014年   117篇
  2013年   197篇
  2012年   287篇
  2011年   264篇
  2010年   172篇
  2009年   127篇
  2008年   201篇
  2007年   218篇
  2006年   201篇
  2005年   173篇
  2004年   157篇
  2003年   155篇
  2002年   147篇
  2001年   46篇
  2000年   43篇
  1999年   51篇
  1998年   52篇
  1997年   36篇
  1996年   32篇
  1995年   36篇
  1994年   25篇
  1992年   41篇
  1991年   42篇
  1990年   25篇
  1989年   36篇
  1988年   34篇
  1987年   26篇
  1986年   36篇
  1985年   46篇
  1984年   31篇
  1983年   26篇
  1982年   22篇
  1980年   15篇
  1979年   15篇
  1975年   14篇
  1974年   22篇
  1973年   16篇
  1972年   15篇
  1971年   14篇
  1970年   13篇
  1968年   12篇
排序方式: 共有4220条查询结果,搜索用时 15 毫秒
1.
Adolescence is a tumultuous and challenging time period in life. Sexual risk behavior among adolescents is a widespread topic of interest in the current literature. Two common factors that influence increased sexual risk behavior are symptoms of depression and negative body image. The purpose of this study was to investigate the effect of body image and symptoms of depression upon sexual risk-taking in an adolescent female population. A secondary data analysis of the 2011 Youth Risk Behavior Survey (YRBS) was used to explore girls’ sexual activity, body image, and mental health. There were 7,708 high-school girls who participated in this study. Three questions were used to represent the constructs under investigation. There were significant correlations between sexual activity, body image, and symptoms of depression; only symptoms of depression were significant predictors of both sexual activity and condom usage. Body image was a predictor of sexual activity, but not condom use. Our findings support previous studies that suggested that people with depressive symptoms were more likely to engage in risky sexual behaviors. Our study also supports the idea that a negative body image decreases sexual activity; however, other researchers have reported that negative body image leads to an increase in sexual activity.  相似文献   
2.
3.
Background Familial partial lipodystrophy (FPLD) is a monogenic form of diabetes characterised by a dominantly inherited disorder of adipose tissue associated with the loss of subcutaneous fat from the limbs and trunk, with excess fat deposited around the face and neck. The lipodystrophy causes severe insulin resistance, resulting in acanthosis nigricans, diabetes, dyslipidaemia, and increased risk of cardiovascular disease. Preliminary results from animals and man suggest that increasing subcutaneous fat by treatment with thiazolidinediones should improve insulin resistance and the associated features of this syndrome. Case report We report a 24-year-old patient with FPLD caused by a mutation in the LMNA gene (R482W) treated with 12 months of rosiglitazone. Subcutaneous fat increased following rosiglitazone treatment as demonstrated by a 29% generalised increase in skin-fold thickness. Leptin levels increased from 5.8 to 11.2 ng/ml. Compared with treatment on Metformin, there was an increase in insulin sensitivity (HOMA S% 17.2–31.6) but no change in glycaemic control. The lipid profile worsened during the follow-up period. Conclusion This initial case suggests that, for modification of cardiovascular risk factors, there are no clear advantages in treating patients with FPLD with rosiglitazone despite increases in subcutaneous adipose tissue. Larger series will be needed to identify moderate beneficial effects and treatment may be more effective in patients with generalised forms of lipodystrophy.  相似文献   
4.
Our understanding of the causes of male infertility and our ability to develop an appropriate range of diagnostic tests are both dependent upon a knowledge of the cellular mechanisms responsible for the regulation of human sperm function. This review examines the intra- and extracellular factors regulating four separate components of human sperm function: sperm transport, sperm-egg recognition, the acrosome reaction and sperm-oocyte fusion. Within each of these areas the fundamental nature of the process, the control mechanisms involved, the availability of appropriate diagnostic tests and the relationship with human infertility have been considered.  相似文献   
5.
A range of 18 derivatives of flavone-8-acetic acid (FAA) with substituents on the 2-phenyl group have been prepared and their anti-tumour activity evaluated in vitro against a panel of human and murine tumour cell lines and in vivo against MAC 15A. There was no clear-cut relationship between in vitro and in vivo activity but the activity in each situation was found to be very sensitive to the precise substitution pattern with closely related isomers giving widely different activities. Some of the compounds, notably 10b,cj , and r , were active in vivo and these require further studies in order to evaluate their potential for development.  相似文献   
6.
7.
The Edinburgh Rehabilitation Status Scale (ERSS) was applied to 129 attenders at a day center for physical disability. All of the attenders had significant neurological impairment dating from birth or from infancy. Fifty-nine of the subjects (46%) had been diagnosed on conventional grounds as having mental handicap as well as physical disability. ERSS scores were compared with Barthel Index scores in all subjects and with PULSES profile in 50 subjects (27 physical disability alone, 23 combined with mental handicap). The ERSS scores clearly demonstrated significant differences in the level of disablement between the two groups in all four subscales as well as in total scores; the Barthel scores showed differences in self-care and total scores, and, to a lesser extent, in mobility. PULSES failed to differentiate the groups except in one of its subscales. The ERSS is a sensitive index of overall function and is useful in highlighting the additive effect of mental handicap and physical disability, a difference which may not be apparent when other assessment scales are used.  相似文献   
8.
A synchronous occurrence of large bowel adenocarcinoma and extragenital malignant mixed mesodermal tumour (MMMT) is reported. This case represents the sixth extragenital MMMT reported in the literature.  相似文献   
9.
The efficacy of metronidazole and doxycycline in preventing recurrent periodontitis was studied in 23 patients. After treatment in the previous 7 months with either bimonthly scaling and 3 weeks of systemic doxycycline (11 subjects) or scaling and placebo (12 subjects), patients were monitored for recurrent periodontitis and were scaled every 2 months. When either a periodontal abscess or greater than 2 mm loss of gingival attachment was observed, metronidazole was administered (250 mg every 8 hours) for 10 days. In the placebo plus metronidazole group, 5 patients (42%) exhibited recurrent periodontitis after the metronidazole regimen compared with only one (9%) in the doxycycline plus metronidazole group (P less than 0.096). Subgingival plaque samples at study and healthy control sites were screened for the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Eikenella corrodens, and Fusobacterium nucleatum by immunofluorescence and for spirochetes using Ryu's stain. Presence/absence analysis of the sum of scores of the 6 individual pathogens demonstrated large reductions (P less than 0.005) in the frequency of detection of pathogens in the former doxycycline compared with the placebo plus metronidazole group at both study and control sites before and one month after metronidazole. By 7 months after metronidazole, there was no detectable difference between groups. These results indicate that prevention of recurrent periodontitis with metronidazole may be enhanced by previous treatment with doxycycline.  相似文献   
10.
A randomized, double-blind, placebo-controlled study was performed to assess the analgesic efficacy of intramuscular nefopam hydrochloride after upper abdominal surgery. Patients received either 20 mg nefopam (n = 23) or matching placebo (n = 26), 90 min before surgery, immediately after surgery, and 6, 12 and 18 h after the end of surgery. The 24-h morphine requirements were measured using a patient-controlled analgesia system delivering on-demand intravenous bolus doses of morphine. Pain was assessed using visual analogue scales. Patients receiving nefopam had a mean (+/- s.e.m.) cumulative morphine consumption of 4.1 +/- 0.8 mg in the first hour, compared with 8.5 +/- 0.8 mg in the control group (P less than 0.01). After 24 h the consumptions were 44.1 +/- 7.2 mg and 62.5 +/- 6.9 mg respectively (P less than 0.05). The pain scores in both groups were similar. This study confirms that nefopam hydrochloride has significant analgesic effects and would be a useful supplement to morphine in the management of postoperative pain.  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