全文获取类型
收费全文 | 187311篇 |
免费 | 64475篇 |
国内免费 | 2332篇 |
专业分类
耳鼻咽喉 | 3538篇 |
儿科学 | 6626篇 |
妇产科学 | 3112篇 |
基础医学 | 19989篇 |
口腔科学 | 10013篇 |
临床医学 | 38359篇 |
内科学 | 47870篇 |
皮肤病学 | 10367篇 |
神经病学 | 23947篇 |
特种医学 | 5958篇 |
外国民族医学 | 3篇 |
外科学 | 32387篇 |
综合类 | 3726篇 |
现状与发展 | 44篇 |
一般理论 | 30篇 |
预防医学 | 17802篇 |
眼科学 | 3756篇 |
药学 | 8457篇 |
23篇 | |
中国医学 | 2324篇 |
肿瘤学 | 15787篇 |
出版年
2024年 | 823篇 |
2023年 | 5410篇 |
2022年 | 2015篇 |
2021年 | 5011篇 |
2020年 | 11093篇 |
2019年 | 13250篇 |
2018年 | 15693篇 |
2017年 | 17359篇 |
2016年 | 18337篇 |
2015年 | 18593篇 |
2014年 | 21135篇 |
2013年 | 23542篇 |
2012年 | 8658篇 |
2011年 | 8484篇 |
2010年 | 15656篇 |
2009年 | 14438篇 |
2008年 | 6354篇 |
2007年 | 4336篇 |
2006年 | 5592篇 |
2005年 | 3741篇 |
2004年 | 2923篇 |
2003年 | 2547篇 |
2002年 | 2479篇 |
2001年 | 3169篇 |
2000年 | 2430篇 |
1999年 | 2435篇 |
1998年 | 2415篇 |
1997年 | 2221篇 |
1996年 | 2228篇 |
1995年 | 1977篇 |
1994年 | 1314篇 |
1993年 | 1064篇 |
1992年 | 975篇 |
1991年 | 826篇 |
1990年 | 652篇 |
1989年 | 651篇 |
1988年 | 629篇 |
1987年 | 491篇 |
1986年 | 427篇 |
1985年 | 380篇 |
1984年 | 314篇 |
1983年 | 345篇 |
1982年 | 258篇 |
1981年 | 221篇 |
1980年 | 154篇 |
1979年 | 117篇 |
1978年 | 143篇 |
1977年 | 139篇 |
1976年 | 104篇 |
1972年 | 93篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
C. Edwin Polk DDS MSD David Buchanan PhD 《American journal of orthodontics and dentofacial orthopedics》2003,124(6):663-669
The cephalometric measurement known as Wits appraisal (AOBO) was studied to determine its importance in diagnosis, treatment, and prediction of treatment success. The Wits appraisal is used primarily to identify unreliable ANB values (those that do not accurately reflect the degree of horizontal jaw discrepancy, ie, those that differ greatly from the AOBO value). Therefore, differences between AOBO and ANB also were evaluated. Because neither measurement alone can assess jaw discrepancies with total accuracy, they were combined, plotted on a scattergram, and divided into equal zones to create a new index of horizontal skeletal discrepancies and treatment predictability. Pretreatment values correspond to treatment difficulty, and posttreatment values correspond to the effectiveness of treatment. Treatment time for each zone also was evaluated. We were able to draw several conclusions from this study. First, combining AOBO and ANB values results in a more accurate measurement of treatment difficulty. These combined values also can be used to predict both treatment time and the success of treatment for horizontal discrepancies. Second, the AOBO value predicts variations in treatment time at each ANB value. Finally, adding ANB and AOBO values and then dividing the total yields zones that represent statistically significant differences in treatment times and percentages of success. The zones also correlate with the difference between AOBO and ANB measurements. 相似文献
42.
Vincent Chung Liang Liu Zhaoxiang Bian Zhongzhen Zhao Wai Leuk Fong Wan Fung Kum Jing Gao Min Li 《Movement disorders》2006,21(10):1709-1715
The objective of this study is to assess the efficacy and safety of herbal medicines (HMs), as a monotherapy or adjunct therapy, compared to placebo or conventional approaches in the treatment of idiopathic Parkinson's disease (PD). We conducted a systematic review of randomized controlled trials from both conventional and alternative medicine sources. Outcome measures were overall improvement, quality of life, reduction of levodopa dose, and adverse events. Nine studies were included, each testing a different HM. Six of the trials had limited internal validity due to major flaws in design, including the lack of proper randomization; insufficient blinding; unclear inclusive criteria in terms of diagnostic criteria, baseline staging, and duration of disease; lack of proper sample size calculation; and insufficient data analysis. Imbalances in gender and ethnicity among the patients in the included trials were observed. No major adverse events emerged, and no specific pattern was detected from the trials describing such data. In addition to major methodological defects, heterogeneity in (1) HM tested, (2) control treatment, and (3) outcome measure hindered in-depth data analysis and synthesis. Current evidence is insufficient to evaluate the efficacy and safety of various HMs. Further studies with improved trial design and reporting, with assessment on cost-effectiveness, quality of life, and qualitative data are warranted. 相似文献
43.
44.
45.
46.
47.
The aim of this study was to design a new intravenous blood–gas exchange device and to estimate the design characteristics
of the device with a dimensionless function by using a substance that can be used instead of bovine blood. In addition, the
characteristics of oxygen transfer were estimated using empirical formulas and the reliability of the equations was ascertained
by comparing their output with an experiment performed using bovine blood. The dimensionless function was derived using distilled
water and bovine blood to estimate the oxygen transfer rate. Using the derived equations, the calculated oxygen transfer rates
for bovine blood and distilled water were similar for Reynolds numbers ranging from 0.7 to 7.0. Therefore, it is possible
to estimate the oxygen transfer rate in bovine blood, which is a non-Newtonian fluid, using distilled water, which is a Newtonian
fluid. Moreover, it was possible to verify the related equations because the oxygen transfer rate could be estimated using
the derived equations, according to the diameters of the various device modules. 相似文献
48.
Abstract: Background: Identification of risk drinking in expectant fathers may be helpful as an important part of efforts to minimize maternal alcohol use, and as an opportunity to inform them about a problematic practice during a critical developmental stage for the couple. The purpose of this study was to evaluate the T‐ACE screening questionnaire, which asks about t olerance to alcohol, being a nnoyed by other's comments about drinking, attempts to c ut down, and having a drink first thing in the morning (“ e ye‐opener”), in the male partners of pregnant women who themselves were T‐ACE positive. Methods: Two hundred fifty‐four male partners were asked to complete the T‐ACE embedded in a health survey, the Alcohol Use Disorders Identification Test (AUDIT), and other questions about their alcohol use in the past 30 days when their pregnant partners had a median gestation of 11.5 weeks (T1). After delivery, male partners again completed the T‐ACE and quantity‐frequency questions (T2). The predictive ability of the T‐ACE and AUDIT was compared, using risk drinking (>4 drinks/day or >14 drinks/week) as the criterion standard. Results: A substantial minority of male partners had risk drinking, 31 percent at T1 and 25 percent at T2. Although the AUDIT was better than the T‐ACE as an independent predictor of risk drinking, the latter was most accurate when the tolerance threshold exceeded 2 drinks, the same established for pregnant women. The sensitivity (T1 = 84.6%, T2 = 82.8%) and specificity (T1 = 43.8%, T2 = 51.1%) of the T‐ACE at this threshold compared favorably with those of the AUDIT at the standard cut point of 8. Conclusions: The T‐ACE may be a practical way for clinicians to identify risk drinking in both pregnant women and expectant fathers. (BIRTH 33:2 June 2006) 相似文献
49.
50.