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   2776篇
  免费   301篇
  国内免费   9篇
耳鼻咽喉   63篇
儿科学   79篇
妇产科学   59篇
基础医学   426篇
口腔科学   98篇
临床医学   247篇
内科学   685篇
皮肤病学   60篇
神经病学   245篇
特种医学   83篇
外科学   331篇
综合类   118篇
一般理论   24篇
预防医学   180篇
眼科学   81篇
药学   159篇
中国医学   3篇
肿瘤学   145篇
  2023年   23篇
  2022年   36篇
  2021年   64篇
  2020年   34篇
  2019年   45篇
  2018年   72篇
  2017年   45篇
  2016年   42篇
  2015年   65篇
  2014年   67篇
  2013年   115篇
  2012年   159篇
  2011年   173篇
  2010年   79篇
  2009年   97篇
  2008年   146篇
  2007年   149篇
  2006年   114篇
  2005年   127篇
  2004年   112篇
  2003年   93篇
  2002年   103篇
  2001年   40篇
  2000年   76篇
  1999年   57篇
  1998年   41篇
  1997年   27篇
  1996年   21篇
  1995年   21篇
  1994年   20篇
  1992年   35篇
  1991年   36篇
  1990年   26篇
  1989年   28篇
  1988年   26篇
  1987年   34篇
  1986年   23篇
  1985年   28篇
  1983年   22篇
  1981年   30篇
  1980年   18篇
  1979年   38篇
  1978年   24篇
  1977年   19篇
  1976年   32篇
  1975年   34篇
  1974年   31篇
  1973年   20篇
  1968年   17篇
  1967年   17篇
排序方式: 共有3086条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
Abstract The effectiveness of a 5% potassium nitrate dentifrice as a daily home treatment for dentinal hypersensitivity was evaluated in a double-blind study in 36 Japanese subjects who complained of cold and/or tactile hypersensitivity. The subjects were divided into 2 groups, with 18 being given a 5% potassium nitrate dentifrice (treated group) and the other 18 a vehicle paste (control group). Both groups were instructed to brush their teeth 2 × a day. The hypersensitivity levels of the affected teeth were assessed by 2 stimuli, one tactile and the other cold air, and by the perception of pain. The results of all 3 assessment methods indicated that the potassium nitrate dentifrice significantly decreased the level of hypersensitivity at weeks 4, 8, and 12. In the treated group, a rapid decrease of positive scores for both the cold air stimulus and the subjective symptoms appeared from week 2. Although a significant decrease of the assessment score was also observed in the control group, the reduction rate of the score was much greater in the treated group by ail 3 assessment methods at weeks 4, 8, and 12. Complete relief of subjective symptoms throughout the 12 weeks’examination was noted in 67% of the subjects in the treated group, but in only 6% in the control group. These results suggest the usefulness of a 5% potassium nitrate dentifrice in Japanese patients with dentinal hypersensitivity.  相似文献   
5.
Objective: To determine the contribution of several variables to fluid loss during transcervical resection of submucous myomas.Design: An observational study using multiple linear regression analyses.Setting: A university-affiliated training hospital and a university department of clinical epidemiology and biostatistics.Patient(s): Patients with submucous myomas.Intervention(s): Transcervical resection of submucous myomas and monitoring of fluid loss.Main Outcome Measure(s): Patient age, uterine enlargement, treatment with GnRH analogues or 8-ornithine-vasopressin, type of anesthesia, number of myomas, intramural extension of the myoma (type of myoma), and operating time were tested as variables.Result(s): Only intramural extension of the myoma and operating time were obviously related to fluid loss. For the other variables, such a relation was weak at best. The relation between fluid loss and operating time was not modified by any of the other variables.Conclusion(s): Because fluid loss is an important limiting factor in the transcervical resection of submucous myomas, special attention should be paid to reduction of the operating time and preoperative assessment of the intramural extension of the myoma to guide appropriate patient selection.  相似文献   
6.
The authors present the third installment of the guidelines and recommendations from the Safety Committee of the Society for Magnetic Resonance Imaging (now the Society of Magnetic Resonance) concerning various issues related to the safety and management of patients undergoing magnetic resonance (MR) procedures. This document was developed to provide standardized and consistent information for use by health practitioners involved in screening patients or other individuals for MR procedures.  相似文献   
7.
Effects of Ethanol on the Contractile Function of the Heart: A Review   总被引:7,自引:0,他引:7  
Chronic ethanol consumption leads to a number of alterations in the contractile function of the heart and is a leading cause of cardiomyopathy. Ethanol also has an acute negative inotropic effect mediated by direct interaction with cardiac muscle cells, although this action is often masked by indirect actions resulting from enhanced release of catecholamines in vivo. This article reviews the effects of ethanol on the contractile function of the heart. The specific targets affected by ethanol in cardiac muscle cells are discussed in terms of potential mechanisms underlying the depressions of contractility resulting from both acute and chronic actions of ethanol.  相似文献   
8.
OBJECTIVE: To ascertain whether maternal twinning influences the previously described association between the birthweight of singleton mothers and their infants. DESIGN AND SUBJECTS: The association between the birthweight of singleton parents and their offspring and that between twin parents and their offspring was compared using data from the 23-year-old sample of the 1958 British national birth cohort. The numbers available for full comparison were 1027 female and 611 male singleton cohort members, and 26 female and 17 male twin cohort members and their first singleton livebirths. RESULTS: Of the mothers who had been twins, half had been of low birthweight, and overall their mean weight was 700 g less than that of their singleton counterparts. Nevertheless, the mean birthweight of babies of twin mothers was 133 g, and of twin fathers 94 g, greater than of babies of corresponding singletons. For female, but not male, parents this difference persisted after adjustment for confounding variables. CONCLUSIONS: We suggest two possible reasons for the difference between the weight of babies of twin and singleton mothers. Firstly, the growth of twins becomes retarded late in pregnancy, possibly after a period critical in determining long-term reproductive effects. Secondly, the twin survivors were of higher birthweight than the original twin cohort, whilst the singleton survivors were more representative of all singleton births, thus introducing a possible bias.  相似文献   
9.
10.
Factors associated with hypertension in Nigerian civil servants   总被引:3,自引:0,他引:3  
BACKGROUND. Study of hypertension in segments of West African populations in transition toward Westernization may lead to better understanding of the high risk for hypertension among Westernized blacks. METHODS. Five hundred fifty-nine urban civil servants, ages 25-54, were recruited from six ministries of Bendel State, Nigeria. Blood pressure, physical measurements, urinary protein and glucose, fasting blood glucose, and demographic data were collected at the workplace. Subjects were classified as senior staff (professionals or administrators) or junior staff (non-administrators). RESULTS. Among 172 male senior staff, the age-adjusted rate of hypertension (diastolic blood pressure > or = 90 mm Hg, systolic blood pressure > or = 140 mm Hg, or on an antihypertensive medication) was 43% and occurrence rose dramatically from 21 to 63% across age groups 25-34 to 45-54, respectively. Among 266 male junior staff, the age-adjusted rate of hypertension was 23%, and occurrence did not rise with age. Logistic regression showed that body mass index (kg/m2), age, alcohol drinking, and being senior staff were all independently related to hypertension in men. On the other hand, the age-adjusted rate of hypertension in 121 women was 20% and was significantly related only to body mass index. CONCLUSION. Male urban civil servants appeared to have a risk for hypertension similar to that of U.S. black males. Age, body mass index, alcohol drinking, and other unidentified factors related to higher socioeconomic status were strong determinants of hypertension in this population.  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