全文获取类型
收费全文 | 12571篇 |
免费 | 861篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 94篇 |
儿科学 | 404篇 |
妇产科学 | 365篇 |
基础医学 | 1542篇 |
口腔科学 | 138篇 |
临床医学 | 2216篇 |
内科学 | 1974篇 |
皮肤病学 | 164篇 |
神经病学 | 1214篇 |
特种医学 | 275篇 |
外科学 | 1226篇 |
综合类 | 222篇 |
一般理论 | 24篇 |
预防医学 | 1506篇 |
眼科学 | 284篇 |
药学 | 820篇 |
2篇 | |
中国医学 | 7篇 |
肿瘤学 | 978篇 |
出版年
2023年 | 60篇 |
2022年 | 129篇 |
2021年 | 218篇 |
2020年 | 143篇 |
2019年 | 227篇 |
2018年 | 259篇 |
2017年 | 208篇 |
2016年 | 203篇 |
2015年 | 233篇 |
2014年 | 317篇 |
2013年 | 579篇 |
2012年 | 777篇 |
2011年 | 887篇 |
2010年 | 470篇 |
2009年 | 454篇 |
2008年 | 804篇 |
2007年 | 813篇 |
2006年 | 880篇 |
2005年 | 857篇 |
2004年 | 908篇 |
2003年 | 850篇 |
2002年 | 756篇 |
2001年 | 166篇 |
2000年 | 108篇 |
1999年 | 138篇 |
1998年 | 157篇 |
1997年 | 131篇 |
1996年 | 98篇 |
1995年 | 103篇 |
1994年 | 77篇 |
1993年 | 79篇 |
1992年 | 100篇 |
1991年 | 69篇 |
1990年 | 77篇 |
1989年 | 66篇 |
1988年 | 59篇 |
1987年 | 63篇 |
1986年 | 78篇 |
1985年 | 62篇 |
1984年 | 65篇 |
1983年 | 67篇 |
1982年 | 54篇 |
1981年 | 67篇 |
1980年 | 74篇 |
1979年 | 42篇 |
1978年 | 45篇 |
1977年 | 38篇 |
1976年 | 32篇 |
1975年 | 33篇 |
1973年 | 35篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
A comparison of student performance in a simulation clinic and a traditional laboratory environment: three-year results 总被引:3,自引:0,他引:3
With simulation clinics, dental schools have improved their preclinical laboratories to provide a more realistic clinical teaching environment. However, there is very little data to support the assumption that these facilities actually improve student performance of technical skills. This study compared the scores of two fixed preparations for full cast crowns by third-year dental students. One of the preparations was made in the simulation clinic manikin, and the other was prepared on the bench top. Three prosthodontic faculty members scored the preparations in the areas of occlusal reduction, axial reduction, resistance and retention, and margination. The study also compared the performance of three classes of dental students: one class with no experience in the simulation clinic, one with one year of experience, and one with two years of experience. The amount of time since completing the fixed prosthodontics course among the students was also evaluated. This was done because the third-year students at the University of Iowa rotate through a series often-week clerkships rather than a comprehensive care model. (Therefore, not all students start clinical prosthodontics at the same time.) In addition, all student participants completed a questionnaire that addressed their perception of their clinical readiness prior to treating their first fixed prosthodontic patient. When we compared the classes of years 1, 2, and 3 by average preparation score, we found a significant difference among the scores for teeth prepared on the bench top (p = 0.0001) but not for the teeth prepared in the mannequin (p = 0.1176). For Year 1 (no simulation clinic experience), the amount of elapsed time following completion of the fixed prosthodontic course was not significant for the tooth prepared on the bench top or in the manikin (p = 0.57113 and 0.0661). For Year 2 (one year of simulation clinic experience), the elapsed time following completion of the fixed prosthodontic course was significant for the tooth prepared on the bench top (p = 0.0482), but it was not significant for the tooth prepared in the manikin (p = 0.2968). For Year 3 (two years of simulation clinic experience), the amount of elapsed time following completion of the fixed prosthodontic course was not significant for the tooth prepared on the bench top or in the manikin (p = 0.7275 and 0.6007). The questionnaire revealed that, in general, the majority of the students perceived their clinical readiness as more than adequate. These results are mixed in that students with more bench top experience scored better on the bench top, and students with more manikin experience scored equally in both environments. 相似文献
12.
13.
Wen?YanEmail author David?Polidori Lynn?Yieh Jianing?Di Xiaodong?Wu Veronica?Moreno Lina?Li Celia?P.?Briscoe Nigel?Shankley G.?Lynis?Dohm Walter?J.?Pories 《Obesity surgery》2014,24(11):1969-1974
Changes in gastrointestinal peptide release may play an important role in improving glucose control and reducing body weight following Roux-en-Y gastric bypass (RYGB), but the impact of low caloric intake on gut peptide release post-surgery has not been well characterized. The purpose of this study was to assess the relationships between low caloric intake and gut peptide release and how they were altered by RYGB. Obese females including ten normoglycemic (ON) and ten with type 2 diabetes mellitus (T2DM) (OD) were studied before, 1 week, and 3 months after RYGB. Nine lean, normoglycemic women were studied for comparison. Subjects were given three separate mixed meal challenges (MMCs; 75, 150, and 300 kcal). Plasma glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) were analyzed. Prior to surgery, only minimal increases in GLP-1 and PYY were observed in response to the MMCs. After surgery, the peak GLP-1 concentration was progressively elevated in response to increasing meal sizes. The meal sizes had a statistically significant impact on elevation of GLP-1 incremental areas under the curve (ΔAUC) in both ON and OD at 1 week and 3 months post-surgery visits (p?<?0.05 for all comparisons). The PYY ?AUC was also significantly increased in a meal size-dependent manner in both ON and OD at both post-surgery visits (p?<?0.05 for all comparisons). Meal sizes as small as 75–300 kcal, which cause minimal stimulation in GLP-1 or PYY release in the subjects before RYGB, are sufficient to provide statistically significant, meal size-dependent increases in the peptides post-RYGB both acutely and after meaningful weight loss occurred. 相似文献
14.
15.
Depressed and socially anxious individuals were compared in terms of their social self-perceptions using the interpersonal problem circle, a conceptualization of the domain of interpersonal problems derived from Horowitz' Inventory of Interpersonal Problems. Subjects who were socially anxious, whether depressed or not, differed significantly from a control group of nondepressed, nonanxious subjects on both dimensions of problematic social behavior. These subjects characterized themselves as nonassertive and socially avoidant. Individuals who were depressed but not socially anxious were no different than control subjects in their social self-perceptions. These results suggest that beliefs and self-perceptions concerning characteristic patterns of interpersonal behavior may distinguish individuals with various types of affective complaints.This research was supported by a grant to Lynn Alden from the Social Sciences and Humanities Research Council of Canada. 相似文献
16.
Lynn J. White MS Jeffrey S. Jones MD Christopher W Felton MD Linda C. Pool RA 《Academic emergency medicine》1996,3(8):745-750
Objective: To identify common discrepancies and average reading grade levels for informed consent forms (ICFs) us submitted to institutional review boards (IRBs) by medical researchers.
Methods: A retrospective evaluation of ICFs as submitted to IRBs of 3 university-affiliated hospitals during a I-year period. ICF content was evaluated using a checklist of 23 requirements specified in the federal regulations governing human research. Documents then were computer-analyzed to determine the readability scores using 2 common indexes of comprehension. A discrepancy was defined as any instance in which an ICF did not address an applicable requirement in the Code of Federal Regulations.
Results: Eighty-two ICFs representing 16 medical specialties were evaluated; 8 (10%) were from emergency medicine. Eighteen ICFs (22%) were conspicuously incomplete, lacking 29 federal requirements. The mean number of discrepancies was 4.7 (95% CI, 3.9–5.5) Common omissions included: a statement about who is doing the research, number of subjects in the study, circumstances when a subject's participation may be terminated, disclosure of alternative procedures, and notice to subjects regarding new findings. The mean Flesch grade level required to read all ICFs was 13.8 (95% CI, 13.5–14.2), implying that the majority of the U.S. adult population would be unable to comprehend these forms.
Conclusion: Designing a consent form to meet all of the federal requirements while maintaining a level of reading comprehension suitable for the general population is a difficult task for investigators. 相似文献
Methods: A retrospective evaluation of ICFs as submitted to IRBs of 3 university-affiliated hospitals during a I-year period. ICF content was evaluated using a checklist of 23 requirements specified in the federal regulations governing human research. Documents then were computer-analyzed to determine the readability scores using 2 common indexes of comprehension. A discrepancy was defined as any instance in which an ICF did not address an applicable requirement in the Code of Federal Regulations.
Results: Eighty-two ICFs representing 16 medical specialties were evaluated; 8 (10%) were from emergency medicine. Eighteen ICFs (22%) were conspicuously incomplete, lacking 29 federal requirements. The mean number of discrepancies was 4.7 (95% CI, 3.9–5.5) Common omissions included: a statement about who is doing the research, number of subjects in the study, circumstances when a subject's participation may be terminated, disclosure of alternative procedures, and notice to subjects regarding new findings. The mean Flesch grade level required to read all ICFs was 13.8 (95% CI, 13.5–14.2), implying that the majority of the U.S. adult population would be unable to comprehend these forms.
Conclusion: Designing a consent form to meet all of the federal requirements while maintaining a level of reading comprehension suitable for the general population is a difficult task for investigators. 相似文献
17.
purpose . To identify sociodemographic and health-related correlates of smoking status among women in households with young children.
design . A secondary analysis of the 1992 California Behavioral Risk Factor Surveillance System public-use data tape
participants . Women (N = 520) in households with very young children (≤ 5 years of age)
main outcome measures . Current smoking status
results . Approximately 18% were current smokers; more than 40% smoked more than 10 cigarettes each day. A majority of smokers indicated a high level of nicotine addiction, but had plans to quit. Smoking prevalence varied by sociodemographic variables with higher rates for unmarried, less than college educated, and unemployed participants. Health status also was related to smoking, with higher rates among those with poor health and those limited in activities.
conclusions . Smoking is one way of coping with the stressors of daily life, including those associated with caring for young children. Special cessation efforts may be needed for the unemployed, the unmarried woman, and for those in poor health. 相似文献
design . A secondary analysis of the 1992 California Behavioral Risk Factor Surveillance System public-use data tape
participants . Women (N = 520) in households with very young children (≤ 5 years of age)
main outcome measures . Current smoking status
results . Approximately 18% were current smokers; more than 40% smoked more than 10 cigarettes each day. A majority of smokers indicated a high level of nicotine addiction, but had plans to quit. Smoking prevalence varied by sociodemographic variables with higher rates for unmarried, less than college educated, and unemployed participants. Health status also was related to smoking, with higher rates among those with poor health and those limited in activities.
conclusions . Smoking is one way of coping with the stressors of daily life, including those associated with caring for young children. Special cessation efforts may be needed for the unemployed, the unmarried woman, and for those in poor health. 相似文献
18.
Judith Gere Ph.D. Lynn M. Martire Ph.D. Francis J. Keefe Ph.D. Mary Ann Parris Stephens Ph.D. Richard Schulz Ph.D. 《Annals of behavioral medicine》2014,48(3):337-346
Background
In addition to patient self-efficacy, spouse confidence in patient efficacy may also independently predict patient health outcomes. However, the potential influence of spouse confidence has received little research attention.Purpose
The current study examined the influence of patient and spouse efficacy beliefs for arthritis management on patient health.Methods
Patient health (i.e., arthritis severity, perceived health, depressive symptoms, lower extremity function), patient self-efficacy, and spouse confidence in patients’ efficacy were assessed in a sample of knee osteoarthritis patients (N?=?152) and their spouses at three time points across an 18-month period. Data were analyzed using structural equation models.Results
Consistent with predictions, spouse confidence in patient efficacy for arthritis management predicted improvements in patient depressive symptoms, perceived health, and lower extremity function over 6 months and in arthritis severity over 1 year.Conclusions
Our findings add to a growing literature that highlights the important role of spouse perceptions in patients’ long-term health. 相似文献19.
20.