全文获取类型
收费全文 | 22053篇 |
免费 | 1500篇 |
国内免费 | 120篇 |
专业分类
耳鼻咽喉 | 285篇 |
儿科学 | 552篇 |
妇产科学 | 413篇 |
基础医学 | 2870篇 |
口腔科学 | 483篇 |
临床医学 | 2105篇 |
内科学 | 4066篇 |
皮肤病学 | 213篇 |
神经病学 | 2731篇 |
特种医学 | 799篇 |
外国民族医学 | 1篇 |
外科学 | 2803篇 |
综合类 | 252篇 |
一般理论 | 14篇 |
预防医学 | 2092篇 |
眼科学 | 754篇 |
药学 | 1821篇 |
中国医学 | 48篇 |
肿瘤学 | 1371篇 |
出版年
2023年 | 91篇 |
2022年 | 141篇 |
2021年 | 354篇 |
2020年 | 214篇 |
2019年 | 321篇 |
2018年 | 429篇 |
2017年 | 345篇 |
2016年 | 337篇 |
2015年 | 392篇 |
2014年 | 608篇 |
2013年 | 941篇 |
2012年 | 1391篇 |
2011年 | 1464篇 |
2010年 | 771篇 |
2009年 | 650篇 |
2008年 | 1342篇 |
2007年 | 1448篇 |
2006年 | 1404篇 |
2005年 | 1457篇 |
2004年 | 1442篇 |
2003年 | 1347篇 |
2002年 | 1310篇 |
2001年 | 287篇 |
2000年 | 270篇 |
1999年 | 299篇 |
1998年 | 291篇 |
1997年 | 272篇 |
1996年 | 222篇 |
1995年 | 246篇 |
1994年 | 164篇 |
1993年 | 197篇 |
1992年 | 194篇 |
1991年 | 178篇 |
1990年 | 175篇 |
1989年 | 175篇 |
1988年 | 126篇 |
1987年 | 162篇 |
1986年 | 146篇 |
1985年 | 167篇 |
1984年 | 152篇 |
1983年 | 145篇 |
1982年 | 180篇 |
1981年 | 200篇 |
1980年 | 168篇 |
1979年 | 118篇 |
1978年 | 116篇 |
1977年 | 133篇 |
1976年 | 109篇 |
1975年 | 72篇 |
1972年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
The authors report the association of erythroleukemia (FAB M6) and fetal hemoglobin (HbF) level of at least 65% after therapy for ovarian carcinoma. The patient's erythrocytes had many signs of reversion to fetal-like erythropoiesis including: elevated HbF with a fetal G gamma/A gamma (gly/ala) of 3/1, low hemoglobin A2 (HbA2), macrocytosis, and increased i antigen. These data and data from other case reports suggest that elevation of HbF to greater than 25% with reversion to fetal-like erythropoiesis is useful in differentiating erythroleukemia from other preleukemic disorders. 相似文献
12.
Recent epidemiologic studies have found that the behaviors that characterize seasonal affective disorder (SAD) show seasonal variation in 92%-95% of the general population, suggesting that seasonal variation in behavior and mood is a continuous, dimensional variable extending throughout the general population, defined at the upper extreme by SAD. Research into population seasonality will require a dimensional measure of seasonal variation in mood and behavior that produces a broad, finely graded distribution of seasonality scores sensitive to individual differences throughout the entire range of scores. Accordingly, the Inventory of Seasonal Variation (ISV) was developed as such a measure. This study demonstrated that the ISV has high internal structural validity and is highly sensitive to individual differences in seasonality across its entire range of scores in the normal population. This latter characteristic is not shared by other existing measures of seasonality. Initial external validity of the ISV was supported in that the mean of ISV scores of a SAD sample was found to lie at the 97th percentile of the normal population of scores. Analysis of ISV scores revealed that a winter pattern of seasonality was reported by over 95% of subjects, a pattern that was more pronounced in women than men, while a summer type of seasonality was reported by only 0.6% of the general population. 相似文献
13.
14.
Physiologic mechanism and preoperative prediction of new-onset dysphagia after laparoscopic Nissen fundoplication 总被引:2,自引:0,他引:2
Dennis Blom M.D. Jeffrey H. Peters M.D. Tom R. DeMeester M.D. Peter F. Crookes M.D. Jeffrey A. Hagan M.D. Steven R. DeMeester M.D. Cedric Bremner M.D. 《Journal of gastrointestinal surgery》2002,6(1):22-28
The aim of this study was to determine whether preoperative physiologic factors can account for and be used to predict the
development of postoperative dysphagia after laparoscopic Nissen fundoplication. One hundred sixty-three patients with gastroesophageal
reflux disease underwent laparoscopic Nissen fundoplication with a median follow-up of 14 months (range 6 to 81 months). Preoperative
dysphagia was present in 37% (60 of 163) and was relieved in all but five patients (92%). Female sex (P = 0.01) and the presence of a stricture (P = 0.02) were the only preoperative variables associated with the presence of preoperative dysphagia. Eight percent (8 of
103) of patients without preoperative dysphagia developed new-onset dysphagia, and of these 63% (5 of 8) had a normal lower
esophageal sphincter (LES) (pressure >6 mm Hg; length >2 cm; abdominal length >1 cm). New-onset dysphagia was significantly
more common in patients with a normal LES (22% [5 of 23] vs. 4% [3 of 80], P = 001). Patients with a normal LES had almost a sixfold increase in the risk of developing dysphagia as those with an abnormal
LES (relative risk = 5.8). Only a preoperative normal LES (P = 0.02) or mean LES pressures (P = 0.04) were positively associated with the development of postoperative dysphagia. The severity of this dysphagia also showed
a strong positive trend of increasing with mean preoperative LES pressures (P = 0.07). Finally, preoperative LES pressure significantly correlated with postoperative LES pressure (r = 0.48, P = 0.01) and with mean residual LES (nadir) pressure (r = 0.33, P = 0.05) offering insight into the mechanism of this dysphagia. In conclusion, preoperative LES parameters play a role in
the development of dysphagia after laparoscopic Nissen fundoplication. Patients with a normal LES or high mean LES pressures
are at increased risk for developing this complication and should be informed of this before laparoscopic Nissen fundoplication.
Presented at the Forty-Second Annual Meeting of The Society for Surgery of the Alimentary Tract, Atlanta, Ga., May 20–23,
2001. 相似文献
15.
16.
Angela Bryan Reuben N Robbins Monica S Ruiz Dennis O'Neill 《Health education & behavior》2006,33(2):154-177
Prisons and prison inmates present important targets for HIV/AIDS prevention interventions. Inmates often have histories of high-risk behavior that place them in danger of contracting HIV/AIDS, and rates of HIV/AIDS tend to be much higher in this population. The goal of this study was to assess the effectiveness of a prison-based HIV/AIDS intervention to change attitudes toward HIV prevention, norms supporting HIV prevention, perceived behavioral control (i.e., self-efficacy) for HIV prevention behaviors, and intentions to engage in HIV prevention behaviors postrelease. The intervention also had the goal of encouraging inmates to become HIV/AIDS peer educators. The intervention appeared most successful at influencing beliefs and behaviors related to peer education and somewhat successful at influencing beliefs and intentions related to condom use. Analyses also showed some significant differences in effectiveness by race/ethnicity. Results are discussed from the perspectives of both research and practice with regard to prison-based HIV prevention efforts. 相似文献
17.
18.
Color Stability of Dry Earth Pigmented Maxillofacial Silicone A-2186 Subjected to Microwave Energy Exposure 总被引:2,自引:0,他引:2
Sudarat Kiat-amnuay DDS MS ; Dennis A. Johnston PhD ; John M. Powers PhD ; Rhonda F. Jacob DDS MS 《Journal of prosthodontics》2005,14(2):91-96
PURPOSE: The purpose of this study was to measure spectrophotometrically the color stability of pigmented A-2186 silicone maxillofacial elastomer with 10% by volume of titanium white dry earth opacifier before and after exposure to microwave energy over a simulated 1.5-year period of microwave sterilization. Materials AND METHODS: A-2186 silicone elastomer opacified with titanium white dry earth pigment, pigmented with 5 cosmetic dry earth pigment colors [no pigment (control) group (Pc), red (Pr), yellow ochre (Py), burnt sienna (Po), and a mixture of Pr + Py + Po color group (P3)], was used in this study. Each of the 5 experimental groups consisted of 5 specimens. All specimens were placed in a 250 ml glass beaker filled with 150 ml of water (replenished for each microwave exposure). An exposure of 6 minutes was used 18 times (simulating 1.5 years of microwave sterilization with one 6 minute exposure monthly). Reflectance values were measured by spectrophotometer. Three- and two-way analyses of variance with repeated measures were performed for the color difference (DeltaE*) with the factors of group/color/months, and group/months, respectively. Means were compared by Tukey Honest Significant Difference (HSD) multiple range test calculated at the 0.05 level of significance using SPSS. RESULTS: The trained human eye can detect color changes (DeltaE*) greater than 1.0. Most DeltaE* values of the red pigment group at all intervals and the mixed pigment group at 15- and 18- month intervals increased significantly greater than 1.0 (p < 0.001) compared with the control group. Yellow and burnt sienna groups remained the most color stable over time with DeltaE* values below 0.35. CONCLUSIONS: Lack of color stability of red dry earth pigmented A-2186 silicone maxillofacial elastomers was clinically significant after 12-month exposure to microwave energy as compared with yellow, burnt sienna, and opacified A-2186 dry earth pigments. 相似文献
19.
Phoebe S. Y. Lo Michael C. F. Tong Dennis A. Revicki Ching Chyi Lee John K. S. Woo Henry C. K. Lam C. Andrew van Hasselt 《Quality of life research》2006,15(5):877-887
Background: The Rhinitis Symptom Utility Index (RSUI), originally developed in the United States, consists of a patient-preference weighting
scheme and a 10-item questionnaire measuring the severity and frequency of rhinitis related symptoms over a 14-day period.
This study aimed to determine whether the Chinese RSUI could adopt the US-based multi-attribute utility function (MAUF) in
scoring rhinitis symptoms. Methods: In a Hong Kong study, 116 Chinese adults with allergic rhinitis completed the RSUI questionnaire and 36-item Short-Form
Health Survey (SF-36) after they had been seen by two otorhinolaryngologists for disease-severity ratings. Respondents then
completed computer-administered direct preference measures, i.e., visual analogue scale (VAS) and standard gamble (SG) assessments.
The VAS and SG data were used to estimate a MAUF for the Chinese-based RSUI. Results: The derived MAUF was somewhat different than the one developed for the US RSUI. Test–retest reliability for the Chinese
RSUI was satisfactory (ICC = 0.71, p<0.001). Scores differentiated among cases with mild, moderate, and severe symptoms (p<0.001); and between those who did and did not require medications to control symptoms (p = 0.031). Findings were significantly correlated with SF-36 domain scores (r = 0.19 to 0.37; p=0.041 to <0.001). When the US-based scoring function was applied to the Chinese subjects, the resulting mean RSUI score was
significantly lower (p<0.001). Comparisons between directly measured VAS and SG scores between the US and Chinese samples, demonstrated significant
differences (all p<0.05), with the US subjects consistently rating rhinitis symptoms as worse than Chinese subjects. Conclusions: The Chinese RSUI has good measurement properties that reflect patient preferences from the Chinese. Results suggest that
there are differences in preference rating between US and Chinese subjects and that use of the US-based preference function
for the RSUI would bias the measurement of rhinitis symptom outcomes in Chinese subjects. 相似文献
20.
This study determined nursing research priorities and focused on the development of a nursing research program within a single institution. Of the 715 nurses within the Department of Nursing, 286 (40%) responded to the first round of a two-round Delphi technique, and 137 (48%) responded to the second. The following clinical priorities were determined: prevention and treatment of pressure sores, pain management, treatment of nosocomial infections, and patient education. Nonclinical priorities included staffing and its effects on turnover and patient care, job satisfaction, and factors influencing the quality of nursing care. Serendipitous findings underscored the relevance of the Department of Nursing's conceptual framework to nursing practice and research, revealed the need for dissemination of current research results, and suggested that nurses want to participate in research without assuming responsibility beyond their expertise. 相似文献