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   664798篇
  免费   40403篇
  国内免费   959篇
耳鼻咽喉   8966篇
儿科学   20993篇
妇产科学   17052篇
基础医学   107107篇
口腔科学   19703篇
临床医学   53294篇
内科学   126833篇
皮肤病学   16314篇
神经病学   48710篇
特种医学   22043篇
外国民族医学   63篇
外科学   94300篇
综合类   9226篇
一般理论   142篇
预防医学   56892篇
眼科学   16210篇
药学   52378篇
中国医学   1631篇
肿瘤学   34303篇
  2021年   5394篇
  2019年   6093篇
  2018年   9585篇
  2017年   6573篇
  2016年   7003篇
  2015年   7805篇
  2014年   9648篇
  2013年   15013篇
  2012年   22488篇
  2011年   24349篇
  2010年   13284篇
  2009年   11406篇
  2008年   21920篇
  2007年   23597篇
  2006年   23400篇
  2005年   22476篇
  2004年   21537篇
  2003年   20359篇
  2002年   19906篇
  2001年   28232篇
  2000年   29646篇
  1999年   24000篇
  1998年   6097篇
  1997年   5137篇
  1996年   5468篇
  1995年   4997篇
  1992年   17646篇
  1991年   18065篇
  1990年   18168篇
  1989年   17274篇
  1988年   15993篇
  1987年   15748篇
  1986年   14916篇
  1985年   14208篇
  1984年   10533篇
  1983年   9038篇
  1979年   10474篇
  1978年   7570篇
  1977年   6475篇
  1976年   6262篇
  1975年   7182篇
  1974年   8610篇
  1973年   8138篇
  1972年   7960篇
  1971年   7653篇
  1970年   7070篇
  1969年   6833篇
  1968年   6539篇
  1967年   5887篇
  1966年   5248篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Clinical Oral Investigations - The aim of this study was the analysis of WNT10A variants in seven families of probands with various forms of tooth agenesis and self-reported family history of...  相似文献   
72.
73.
Food-grade titanium dioxide (E171) is widely used as a food additive, and it is known that after oral consumption, E171 is translocated into the bloodstream reaching the highest titanium level at 6 h. E171 is accumulated in some organs triggering toxicity, but the effects on the blood parameters after oral consumption have been less studied. Recently, evidence shows that oral exposure to E171 induces behavioral signs of anxiety and depression. The relation between blood alterations and psychiatric disorders has been previously demonstrated. However, the oral exposure to E171 effects on alterations in blood parameters and effects linked to alterations in animal behavior has not been explored. In this short communication, we aimed to investigate the effects of E171 on specific blood parameters (hematocrit, hemoglobin, number of erythrocytes, and leukocytes) and anxiety and compulsive-like behavior in males and females orally exposed to ~5 mg/kg for 4 weeks. The results showed that E171 decreased hematocrit and hemoglobin in male but not in female mice while leukocyte and erythrocyte count remained unaltered. Oral consumption of E171 decreased the levels of anxiety-like behavior in females but not in male mice, while compulsive-like behavior was increased in both male and female mice.  相似文献   
74.
75.
ObjectiveIdentify factors associated with healthcare providers' frequency of depot medroxyprogesterone acetate (DMPA) provision to adolescents.Study designWe analyzed data from surveys mailed to a nationally representative sample of public-sector providers and office-based physicians (n=1984). We estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of factors associated with frequent DMPA provision to adolescents in the past year.ResultsAlthough most providers (>95%) considered DMPA safe for adolescents, fewer reported frequent provision (89% of public-sector providers; 64% of office-based physicians). Among public-sector providers, factors associated with lower odds of frequent provision included working in settings without Title X funding (aOR 0.44, 95% CI 0.30–0.64), reporting primary care as their primary clinical focus versus reproductive or adolescent health (aOR 0.42, 95% CI 0.28–0.61), and providing fewer patients with family planning services. Among office-based physicians, factors associated with lower odds of frequent provision included specializing in obstetrics/gynecology (aOR 0.50, 95% CI 0.27–0.91) and family medicine (aOR 0.21, 95% CI 0.09–0.47) versus adolescent medicine, completing training ≥15 versus <5 years ago (aOR 0.27, 95% CI 0.09–0.83), and reporting that 0–24% of patients pay with Medicaid or other government healthcare assistance versus ≥50% (aOR 0.23, 95% CI 0.09–0.61). The reason most commonly reported by providers for infrequent DMPA provision was patient preference for another method.ConclusionsWhile most providers reported frequently providing DMPA to adolescents, training on evidence-based recommendations for contraception, focused on subgroups of providers with lower odds of frequent DMPA provision, may increase adolescents' access to contraception.ImplicationsAlthough >95% of providers considered depot medroxyprogesterone (DMPA) a safe contraceptive for adolescents, only 89% of public-sector providers and 64% of office-based physicians reported frequently providing DMPA to adolescents. Provider training on evidence-based recommendations for contraception counseling and provision may increase adolescents' access to DMPA and all methods of contraception.  相似文献   
76.
77.
Rheological behaviour of pharmaceutical semisolid preparations significantly affects manufacturing process, administration, stability, homogeneity of incorporated drug, accuracy of dosing, adhesion in the place of application, drug release, and resulting therapeutic effect of the product. We performed test of consistency by penetrometry, rotational, oscillation and creep tests, and squeeze and tack tests of model samples to introduce methods suitable for characterization and comparison of semisolids in practice. Penetrometry is a simple method allowing sorting the semisolids to low and high stress-resistant materials but deficient for rheological characterization of semisolids. Value of yield stress, generally considered to be appropriate feature of semisolids, is significantly influenced by the method of testing and the way of evaluation. The hysteresis loops of model semisolids revealed incomplete thixotropy, therefore, three-step thixotropy test was employed. Semisolids showed nonlinear response in the creep phase of tests and partial recovery of structure by storing energy in the recovery phase. Squeeze and tack tests seem to be convenient ways for comparison of semisolids. Our study can contribute to a better understanding of different flow behaviour of semisolids given by different physicochemical properties of excipients and can bring useful approaches to evaluation and comparison of semisolids in practice.  相似文献   
78.
Bulletin of Experimental Biology and Medicine - Fast neutron therapy, which previously has demonstrated effective results, but along with a large number of complications, can again be considered a...  相似文献   
79.
Background: Most theoretical models of self-determination suggest that both environmental and personal factors influence the development of self-determination. The design and implementation of interventions must be conducted with foreknowledge of such mediating and moderating factors if the intervention is to be successful.

Methods: The purpose of this study was to examine the degree to which several personal factors and school characteristics affect and explain students’ self-determination. A total of 232 students with intellectual disability from Spain participated. Their self-determination level was assessed by the ARC-INICO Scale.

Results: Students with moderate levels of intellectual disability obtained significantly lower scores on self-determination than their peers with mild intellectual disability. There were significant differences in relation to the level of support needs and their experience with transition programs. The level of support needs was a significant predictor.

Conclusion: These findings contribute to current research in this field and practical implications were discussed.  相似文献   

80.
Journal of Digital Imaging - Vertebral Compression Fracture (VCF) occurs when the vertebral body partially collapses under the action of compressive forces. Non-traumatic VCFs can be secondary to...  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