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   67591篇
  免费   5106篇
  国内免费   1109篇
耳鼻咽喉   684篇
儿科学   1451篇
妇产科学   1273篇
基础医学   10423篇
口腔科学   973篇
临床医学   8371篇
内科学   11421篇
皮肤病学   1499篇
神经病学   6263篇
特种医学   2396篇
外国民族医学   5篇
外科学   6946篇
综合类   2758篇
现状与发展   8篇
一般理论   42篇
预防医学   5465篇
眼科学   1449篇
药学   5710篇
  15篇
中国医学   1103篇
肿瘤学   5551篇
  2024年   61篇
  2023年   591篇
  2022年   1142篇
  2021年   2387篇
  2020年   1448篇
  2019年   1857篇
  2018年   2158篇
  2017年   1706篇
  2016年   2024篇
  2015年   2484篇
  2014年   3201篇
  2013年   3764篇
  2012年   5631篇
  2011年   5807篇
  2010年   3276篇
  2009年   2842篇
  2008年   4421篇
  2007年   4377篇
  2006年   3930篇
  2005年   3932篇
  2004年   3335篇
  2003年   3010篇
  2002年   2708篇
  2001年   946篇
  2000年   869篇
  1999年   868篇
  1998年   655篇
  1997年   543篇
  1996年   403篇
  1995年   399篇
  1994年   327篇
  1993年   281篇
  1992年   281篇
  1991年   278篇
  1990年   228篇
  1989年   202篇
  1988年   166篇
  1987年   146篇
  1986年   131篇
  1985年   98篇
  1984年   105篇
  1983年   89篇
  1982年   89篇
  1981年   87篇
  1980年   87篇
  1979年   62篇
  1978年   48篇
  1977年   53篇
  1976年   42篇
  1974年   41篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The aim of the study was to explore the relationship between college graduates’ dual self-consciousness, job search clarity and perceived stress, and reveal the mediating role of perceived stress between dual self-consciousness and job search clarity. In this study, 467 college graduates were investigated using the Dual Self-Consciousness Scale, Job Search Clarity Scale, and Perceived Stress Scale. After controlling for gender, age, and region, the results revealed that: (1) private self-consciousness has a significant positive predictive effect on job search clarity; (2) perceived stress has a significant negative predictive effect on job search clarity; (3) perceived stress plays partial mediation effects between private self-consciousness and job search clarity; (4) perceived stress plays complete mediation effects between public self-consciousness and job search clarity; (5) perceived stress has suppressing effects between public self-consciousness and job search clarity.  相似文献   
42.
43.
BACKGROUND: Presently, complementary and alternative medicine, including both therapies and herbal/oral supplements, is used globally. Few studies have examined the use of specific therapies, separate from herbal/oral supplements, in cardiac rehabilitation. This paper presents a systematic evaluation of current research evidence related to use of specific complementary and alternative medicine therapies in secondary prevention of cardiovascular disease, with a view to making recommendations for cardiac rehabilitation. DESIGN AND METHODS: A literature search was conducted using complementary and alternative medicine websites, Medline, Allied and Complementary Medicine, CINAHL, Cochrane databases, EMBASE, SportDiscus, Clinical Evidence, and Evidence-Based Practice to locate research-based scientific evidence related to the use of complementary and alternative medicine in cardiac rehabilitation. Search keywords included heart, cardiac, cardiovascular, coronary, myocardial and rehabilitation, combined with particular therapies. Herbal/oral supplements were not included in this evaluation. RESULTS: Some complementary and alternative medicine therapies may be useful to patients by themselves or coupled with traditional cardiac rehabilitation. Tai chi, as a complement to existing exercise interventions, can be utilized for low and intermediate risk patients. transcendental meditation may be used as a stress reduction technique. There was insufficient evidence found for the use of acupuncture or chelation therapy in cardiac rehabilitation or secondary prevention. CONCLUSIONS: Some complementary and alternative medicine therapies hold promise for patients in cardiac rehabilitation. Further research is essential, however, in all areas of complementary and alternative medicine to confirm its usefulness as an adjunct to cardiac rehabilitation.  相似文献   
44.
Background. It has been reported that gender differences in cardiovascular outcomes found in adults also are present in children who undergo surgical repair for congenital heart disease. Methods. California statewide hospital discharge data 1989–99 were used to study outcomes in children <18 years undergoing cardiac surgery. Hospital discharge data were linked to death registry data to study postdischarge death within 30 days of discharge. We used logistic regression to evaluate the effect of gender on mortality controlling for age, race and ethnicity, type of insurance, household income, date and month of surgery, type of admission, hospital case volume, and various types of procedures. Results. There were 25 402 cardiac surgery cases with 1505 in‐hospital deaths (mortality rate of 5.92%). An additional 37 deaths occurred within 30 days after hospital discharge. Crude mortality rates for males (5.99%) and females (5.84%) were not significantly different. However, fewer neonates were female and females underwent a higher proportion of low‐risk procedures than males. Logistic regression revealed that females, compared with males, had a significantly higher odds ratio (OR) for in‐hospital mortality (OR = 1.18, P < .01) and overall (up to 30 days post discharge) mortality (OR = 1.18, P < .01). The risk‐adjusted length of hospital stay was similar between females and males while charges per hospital day were slightly higher in females than males. The prevalence of Down syndrome, pulmonary hypertension, and failure to thrive were higher in females. Conclusions. Female gender is associated with an 18% higher in‐hospital and 30‐day postdischarge mortality as compared with male gender. There was no difference in length of hospital stay between males and females. The mechanism by which female gender acts as a risk factor requires further investigation.  相似文献   
45.
46.
皮质发育障碍模型的建立及其致痫敏感性的研究   总被引:1,自引:0,他引:1  
目的:建立皮质发育障碍模型,探讨皮质发育障碍模型的敏感性。方法:在SD大鼠孕17d腹腔注入1,3-二氯乙烯-亚硝基脲(BCNU)制作皮质发育障碍模型;Nissl染色观察P60d仔鼠病理变化;选取P60d雄性仔鼠,腹腔注射氯化锂-毛果芸香碱,分别比较两组大鼠癫发生的潜伏期、持续状态时间和死亡率。结果:同龄仔鼠脑组织湿重实验组比对照组显著减轻(P<0.01);Nissl染色显示皮质变薄、皮质层次紊乱、海马区域异位细胞异常聚集;有皮质发育障碍的仔鼠注射氯化锂-毛果芸香碱后,癫发生的潜伏期显著缩短(P<0.01),癫持续状态时间延长(P<0.01),死亡率显著升高(P<0.05)。结论:BCNU致皮质发育障碍模型具有癫易感性。  相似文献   
47.
Abstract: Background: Fetal pulse oximetry improves the assessment of fetal well‐being during labor. The objective of this study was to evaluate women's satisfaction with their experience with this additional technology. Methods: We surveyed women participating in the FOREMOST trial, a randomized controlled trial comparing the addition of fetal pulse oximetry (FPO) to conventional cardiotocograph (CTG) monitoring (intervention group), versus CTG‐only (control group), in the presence of nonreassuring fetal status during labor. Our survey evaluated 3 aspects of women's experience: labor, fetal monitoring, and participation in the research. The survey was administered within a few days of giving birth and repeated 3 months later. Results: No differences were found between the intervention and control groups for women's evaluations of their labor, fetal monitoring, research, or overall experiences when surveyed on both occasions. Within each study group, a small but statistically significant decline occurred in women's scores for their experience of labor and overall experience from the initial survey close to the time of giving birth, to 3 months later. The magnitude of differences in responses over time was similar for the both groups. Women were more satisfied after a spontaneous or assisted vaginal birth than after cesarean section. Length of time the research midwife was present had a significant positive effect on women's ratings of their experience several days after giving birth (p = 0.006), but no effect at 3 months. Conclusions: The addition of fetal pulse oximetry for the assessment of fetal well‐being during labor did not affect childbearing women's perceptions of fetal monitoring or their labor. Women evaluated their experience in the research process positively overall. Small changes occurred in women's perception of their satisfaction over time. (BIRTH 33:2 June 2006)  相似文献   
48.
Although surgical lung resection could improve prognosis in some patients with multidrug-resistant tuberculosis (MDR-TB), there are no reports on the optimal candidates for this surgery. The aim of the present study was to elucidate the prognostic factors for surgery in patients with MDR-TB. Patients who underwent lung resection for the treatment of MDR-TB between March 1993 and December 2004 were included in the present study. Treatment failure was defined as greater than or equal to two of the five cultures recorded in the final 12 months of treatment being positive, any one of the final three cultures being positive, or the patient having died during treatment. The variables that affected treatment outcomes were identified through univariate and multivariate logistic regression analysis. In total, 79 patients with MDR-TB were included in the present study. The treatment outcomes of 22 (27.8%) patients were classified as failure. A body mass index <18.5 kg x m(-2), primary resistance, resistance to ofloxacin and the presence of a cavitary lesion beyond the range of the surgical resection were associated with treatment failure. Low body mass index, primary resistance, resistance to ofloxacin and cavitary lesions beyond the range of resection are possible poor prognostic factors for surgical lung resection in multidrug-resistant tuberculosis patients.  相似文献   
49.
BACKGROUND: Few data are currently available investigating neurosteroids (NS) in Alzheimer's disease (AD). The NS allopregnanolone may be decreased in serum and plasma in patients with AD, but it is unclear if allopregnanolone is also reduced in brain. Because a number of NS exhibit neuroprotective effects and impact cognitive performance in rodent models, these molecules may be relevant to the pathophysiology of neurodegenerative disorders. We therefore investigated prefrontal cortex (PFC) NS levels in AD. METHODS: Neurosteroid levels (allopregnanolone, pregnenolone, dehydroepiandrosterone [DHEA]) were determined in postmortem PFC in 14 male subjects with AD and 15 cognitively intact male control subjects by gas chromatography/mass spectrometry preceded by high-performance liquid chromatography purification. RESULTS: Subjects with AD exhibit significant reductions in allopregnanolone compared with cognitively intact control subjects (median levels = 2.50 ng/g vs. 5.59 ng/g, respectively; p = .02). Allopregnanolone levels are inversely correlated with neuropathological disease stage (Braak), r = -.49, p = .007. Median DHEA levels are elevated in subjects with AD (p = .01). CONCLUSIONS: Subjects with AD demonstrate significant reductions in PFC allopregnanolone levels, a finding that may be relevant to neuropathological disease stage severity. Neurosteroids may have utility as candidate biomarkers in AD.  相似文献   
50.
BACKGROUND CONTEXT: Substantial variation exists regarding the use of sedation before interventional spine techniques. Patient preference should play an important role in decision making regarding the need for sedation. However, little is known about patients' anxiety levels before spinal injections and their perceptions about the necessity of sedation. PURPOSE: To determine patient perception for need for sedation before epidural steroid injections and zygapophyseal joint injections. STUDY DESIGN/SETTING: Survey of consecutive spinal injection patients in an outpatient spine center. PATIENT SAMPLE: 500 consecutive lumbar, thoracic, and cervical patients receiving spinal injections. OUTCOME MEASURES: A 12-item questionnaire assessing patients' perceived anxiety before to a spinal injection. METHODS: Subjects were given the questionnaire after their spinal injection. Percentages requesting sedation for a first and potential second procedure were assessed. Additionally, anxiety level and pain rating, location of injection, age, sex, and other medication use were analyzed to determine the effect on the request for sedation. RESULTS: 17% of patients questioned requested sedation before an injection, and 28% would request sedation if they were to have a second injection. CONCLUSIONS: Routine sedation before diagnostic and therapeutic injections is not necessary as the majority of patients would not request sedation before the procedure when given the option. However, in some patients sedation is indicated, and all patients would benefit from educational material on sedation before the injection.  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