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   3262篇
  免费   251篇
  国内免费   16篇
耳鼻咽喉   33篇
儿科学   80篇
妇产科学   85篇
基础医学   313篇
口腔科学   47篇
临床医学   264篇
内科学   1018篇
皮肤病学   92篇
神经病学   209篇
特种医学   92篇
外科学   568篇
综合类   77篇
一般理论   1篇
预防医学   176篇
眼科学   63篇
药学   145篇
中国医学   20篇
肿瘤学   246篇
  2024年   3篇
  2023年   59篇
  2022年   126篇
  2021年   246篇
  2020年   150篇
  2019年   176篇
  2018年   226篇
  2017年   133篇
  2016年   120篇
  2015年   115篇
  2014年   161篇
  2013年   202篇
  2012年   273篇
  2011年   240篇
  2010年   145篇
  2009年   96篇
  2008年   153篇
  2007年   179篇
  2006年   161篇
  2005年   137篇
  2004年   127篇
  2003年   95篇
  2002年   92篇
  2001年   11篇
  2000年   12篇
  1999年   9篇
  1998年   6篇
  1997年   7篇
  1996年   8篇
  1995年   11篇
  1994年   7篇
  1993年   11篇
  1992年   4篇
  1991年   3篇
  1990年   3篇
  1989年   5篇
  1988年   2篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1981年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1974年   2篇
  1970年   1篇
  1943年   1篇
  1923年   2篇
排序方式: 共有3529条查询结果,搜索用时 15 毫秒
61.

Objective

To determine adverse event rates for adult cranial neuro-oncologic surgeries performed at a high-volume quaternary academic center and assess the impact of resident participation on perioperative complication rates.

Patients and Methods

All adult patients undergoing neurosurgical intervention for an intracranial neoplastic lesion between January 1, 2009, and December 31, 2013, were included. Cases were categorized as biopsy, extra-axial/skull base, intra-axial, or transsphenoidal. Complications were categorized as neurologic, medical, wound, mortality, or none and compared for patients managed by a chief resident vs a consultant neurosurgeon.

Results

A total of 6277 neurosurgical procedures for intracranial neoplasms were performed. After excluding radiosurgical procedures and pediatric patients, 4151 adult patients who underwent 4423 procedures were available for analysis. Complications were infrequent, with overall rates of 9.8% (435 of 4423 procedures), 1.7% (73 of 4423), and 1.4% (63 of 4423) for neurologic, medical, and wound complications, respectively. The rate of perioperative mortality was 0.3% (14 of 4423 procedures). Case performance and management by a chief resident did not negatively impact outcome.

Conclusion

In our large-volume brain tumor practice, rates of complications were low, and management of cases by chief residents in a semiautonomous manner did not negatively impact surgical outcomes.  相似文献   
62.

Objective

To assess the effect of race on the incidence of aortic stenosis (AS) and utilization and outcomes of aortic valve replacement (AVR).

Patients and Methods

Patients older than 60 years hospitalized with a primary diagnosis of AS and those who underwent AVR between 2003 and 2014 were included. Adjusted and unadjusted incidence of AS-related hospitalizations, utilization rates of AVR, in-hospital morbidity and mortality, and resource utilization was compared between whites and African Americans (AAs).

Results

Between January 1, 2003, and December 31, 2014, the incidence of AS-related admissions increased from 13 (95% CI, 12.8-13.2) to 26 (95% CI, 25.7-26.4) cases per 100,000 patient-years in whites and from 3 (95% CI, 3.5-3.8) to 9.5 (95% CI, 9.4-9.8) cases per 100,000 patient-years in AAs (P<.001). The incidence density ratio decreased from 4.3 (95% CI, 2.27-6.6) in 2003 to 2.7 (95% CI, 1.1-3.8) in 2014. The ratio of AVR to AS-related admissions was 11.3% in whites and 6.7% in AAs (P<.001). Crude in-hospital mortality after AVR was higher in AAs (6.4% vs 4.7%; P<.001). However, after propensity score matching, in-hospital morality after isolated AVR was not significantly different between AAs and whites (4.7% vs 3.7%; P=.12). African Americans also had longer hospitalizations (12±12 days vs 10±9 days; P<.001), higher rates of nonhome discharge (32.1% vs 27.2%; P=.004), and higher cost of hospitalization ($55,631±$37,773 vs $52,521±$38,040; P<.001).

Conclusions

African Americans undergo AVR less than whites. The underlying etiology of this disparity is multifactorial, but may be related to a lower incidence of AS in AAs. Aortic valve replacement is associated with similar risk-adjusted in-hospital mortality but higher cost and longer hospitalizations in AAs than in whites.  相似文献   
63.
Implantable cardioverter defibrillators (ICDs) have been shown to have a significant benefit in reducing sudden cardiac death (SCD) in patients with systolic heart failure. Additionally, cardiac devices as a bridge to transplant or destination therapy are often used in patients with end‐stage systolic heart failure. As a result, most patients with left ventricular assist devices (LVADs) also have an ICD. Here, we present an electromagnetic interference (EMI) between HeartMate 3 LVAD and ICD. This issue might be critical for both electrophysiologists and advanced heart failure cardiologists to understand prior to implantation of ICD/LVADs in these patients.  相似文献   
64.
Fungal diversity in the Hyrcanian forests can greatly vary due to diverse ecological conditions. The scope of the present research was to investigate the diversity of wood decay fungi at three sites in the northern forests of Iran. Fruiting bodies of fungi were collected in three plots dominated by Quercus castaneifolia C.A.M. (oak) and Carpinus betulus L. (hornbeam) in the Hyrcanian Forest. As many as 19 and 13 taxa were found on hornbeam and oak, respectively. The identification of these fungi revealed Fomes fomentarius (L.) Fr. and Ganoderma lucidum (Curtis) P. Karst. as highly abundant on hornbeam and oak, respectively. Highest fungal abundance was observed at an altitude range of 1150-1200 meters above sea level. Diversity of macro-fungi was determined and the mean Shannon diversity index was found to be 2.52 and 1.94 for hornbeam and oak, respectively, and mean equitability was calculated as 0.84 and 0.73 for hornbeam and oak, respectively. There were no significant differences in the Shannon Diversity Index or equitability. Overall, current work showed that most of the identified fungi were classified as white rot fungi.  相似文献   
65.
Objectives: This study aimed to examine “intention to” and “performance of” oral hygiene care to stroke patients using the Theory of Planned Behavior.

Materials and methods: A large scale survey of 13 centers in Malaysia was conducted involving 806 nurses in relation to oral hygiene care intentions and practices. In addition, information on personal and environmental factors was collected.

Results: The response rate was 95.6% (778/806). The domains of the Theory of Planned Behavior were significantly associated with general intention to perform oral hygiene care: attitudes (β?=?0.21, p?p?p?p?<0.01), controlling for other factors. Knowledge scores, training, access to oral hygiene guidelines and kits, as well as working ward type were identified as key factors associated with intention and practice of oral hygiene care.

Conclusion: The Theory of Planned Behavior provides understanding of “intention to” and “performance of” oral hygiene care to stroke patients. Several provider and environmental factors were also associated with intentions and practices. This has implications for understanding and improving the implementation of oral hygiene care in stroke rehabilitation.

  • Implications for Rehabilitation
  • Oral hygiene care is crucial for stroke patients as it can prevent oral health problems and potentially life threatening events (such as aspiration pneumonia).

  • Despite oral hygiene care being relative simple to perform, it is often neglected during stroke rehabilitation.

  • A large-scale national survey was conducted to understand “intentions to” and “performance of” oral hygiene care to stroke patients using the Theory of Planned Behavior social cognition model.

  • These study findings may have implications and use in promoting oral hygiene care to stroke patients:i) by understanding the pathways and influences to perform oral hygiene care.ii) to conduct health promotion and health education based on behavioral models such as Theory of Planned Behavior.

  相似文献   
66.
Background: Interleukin 18 (IL-18) exerts pleiotropic roles in many inflammatory-related diseases including parasitic infection. Previous studies have demonstrated the promising therapeutic potential of modulating IL-18 bioactivity in various pathological conditions. However, its involvement during malaria infection has yet to be established. In this study, we demonstrated the effect of modulating IL-18 on the histopathological conditions of malaria infected mice. Methods: Plasmodium berghei ANKA infection in male ICR mice was used as a model for malaria infection. Modulation of IL-18 release was carried out by treatment of malarial mice with recombinant mouse IL-18 (rmIL-18) and recombinant mouse IL-18 Fc chimera (rmIL-18Fc) intravenously. Histopathological study and analysis were performed on major organs including brain, liver, spleen, lungs and kidney. Results: Treatment with rmIL-18Fc resulted in significant improvements on the histopathological conditions of the organs in malaria-infected mice. Conclusion: IL-18 is an important mediator of malaria pathogenesis and targeting IL-18 could prove beneficial in malaria-infected host.Key Words: Malaria, Interleukin-18, Plasmodium berghei, Histopathology  相似文献   
67.
68.
BACKGROUND: The diagnostic yield and safety of trans-gastric EUS-guided FNA of the left adrenal gland are not well defined. METHODS: All patients with an enlarged left adrenal gland on abdominal imaging and known or suspected malignancy referred to two EUS centers over a 3-year period were included in this study. EUS-guided FNA was performed on an outpatient basis by one of 4 experienced endosonographers. RESULTS: Thirty-one consecutive patients (21 men, 10 women; mean age 64.8 years) were evaluated. Tissue adequate for interpretation was obtained in all patients; no attempt to obtain tissue was unsuccessful. The median number of needle passes was 4.5 (range 1-8). No immediate complications were encountered. EUS-guided FNA confirmed malignant left adrenal involvement in 42% (13/31) of the patients. Patients with malignant left adrenal masses were more likely to have known cancer at another site (OR 12.0: 95% CI[1.6, 87.9]). Patients with benign masses were more likely to have preservation of the normal sonographic appearance of the adrenal gland ("seagull" configuration) compared with those with malignant masses (OR 9.8: 95% CI[1.9, 51.0]). The accuracy of EUS imaging based on size (> or =3 cm) alone was 81%: 95% CI[63, 93]). Of the patients with malignant adrenal masses, 85% (11/13) died or their clinical condition deteriorated during follow-up, while 15% (2/13) were being treated and were stable clinically. CONCLUSIONS: EUS-guided FNA of the left adrenal gland is a minimally invasive, safe, and highly accurate method that confirms or excludes malignant adrenal involvement in patients with thoracic or GI malignancies.  相似文献   
69.
OBJECTIVES: To compare the rapid shallow breathing index (RSBI) under different ventilatory support settings prior to extubation trials. DESIGN: Prospective study. SETTING: Cardiac surgery unit at a university hospital. PATIENTS: A total of 33 coronary artery bypass grafting patients ready for extubation. INTERVENTIONS: Enrolled patients received a continuous positive airway pressure (CPAP) trial of 5 cm H(2)O and fraction of inspired oxygen (FIO(2)) of 40% (condition 1), a CPAP trial of 5 cmH(2)O and FIO(2) of 21% (condition 2), and a 1-min spontaneously breathing room air trial without ventilatory support (condition 3). These trials were applied in random order. Measurements and main results: Average values of respiratory frequency and tidal volume were measured under the three experimental conditions in all patients immediately prior to extubation. The RSBIs were determined for each patient under each condition; the average RSBIs under conditions 1, 2, and 3 were compared for significance. The average RSBIs (+/- SD) were significantly smaller under condition 1 (34 +/- 13) and condition 2 (36 +/- 14) compared to condition 3 (71 +/- 24). There was no significant difference in RSBI between conditions 1 and 2. CONCLUSIONS: The administration of 5 cm H(2)O of CPAP can influence the determination of the RSBI. In contrast, changes in FIO(2) have no effect on RSBI determination. We speculate that using the RSBI during CPAP may mislead the clinician into premature discontinuation of mechanical ventilation. Consequently, different threshold values for the RSBI should be derived for different ventilatory support levels.  相似文献   
70.
A cross-sectional survey of 365 individuals, (51.9% males, 48.1% females; ages 5-85 years), from five remote interior communities in upper Rejang River basin Sarawak, Malaysia, found 24.4% were anemic. The range and mean of Hb concentration in male and female were: 7.2-17.0 mg/ml and 13.7 mg/ml and 7.9-15.7 mg/ml and 12.9 mg/ml respectively. Amongst the five tribes surveyed, the prevalence of anemia (range: 10.6-46.7%), was higher among the Penans (46.7%), Kenyahs (31.1%), Kajangs (27.8%) and Kayans (19.3%), than amongst the Ukits (10.6%). Anemia is more common among males >40 years and among adolescents and young reproductive females, as well as elderly females > 61 years old. Of the 83 anemic individuals, 6.0% and 3.6% had Trichuris trichiura or hookworm respectively; however there is no clear association with intestinal worm infection.  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