全文获取类型
收费全文 | 22612篇 |
免费 | 2175篇 |
国内免费 | 64篇 |
专业分类
耳鼻咽喉 | 371篇 |
儿科学 | 690篇 |
妇产科学 | 362篇 |
基础医学 | 3229篇 |
口腔科学 | 594篇 |
临床医学 | 2289篇 |
内科学 | 4129篇 |
皮肤病学 | 295篇 |
神经病学 | 1695篇 |
特种医学 | 800篇 |
外科学 | 3340篇 |
综合类 | 533篇 |
一般理论 | 26篇 |
预防医学 | 2444篇 |
眼科学 | 656篇 |
药学 | 1438篇 |
中国医学 | 16篇 |
肿瘤学 | 1944篇 |
出版年
2021年 | 294篇 |
2020年 | 170篇 |
2019年 | 260篇 |
2018年 | 341篇 |
2017年 | 262篇 |
2016年 | 300篇 |
2015年 | 328篇 |
2014年 | 474篇 |
2013年 | 714篇 |
2012年 | 1018篇 |
2011年 | 1014篇 |
2010年 | 567篇 |
2009年 | 502篇 |
2008年 | 887篇 |
2007年 | 1013篇 |
2006年 | 959篇 |
2005年 | 982篇 |
2004年 | 872篇 |
2003年 | 877篇 |
2002年 | 795篇 |
2001年 | 760篇 |
2000年 | 769篇 |
1999年 | 682篇 |
1998年 | 297篇 |
1997年 | 285篇 |
1996年 | 275篇 |
1995年 | 228篇 |
1994年 | 248篇 |
1993年 | 216篇 |
1992年 | 595篇 |
1991年 | 522篇 |
1990年 | 491篇 |
1989年 | 513篇 |
1988年 | 463篇 |
1987年 | 434篇 |
1986年 | 407篇 |
1985年 | 392篇 |
1984年 | 329篇 |
1983年 | 266篇 |
1982年 | 212篇 |
1981年 | 219篇 |
1979年 | 293篇 |
1978年 | 263篇 |
1977年 | 181篇 |
1976年 | 167篇 |
1975年 | 189篇 |
1974年 | 253篇 |
1973年 | 195篇 |
1972年 | 203篇 |
1971年 | 169篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Comparative studies of the pharmacological effects of the d- and l-isomers of codeine 总被引:1,自引:0,他引:1
Opiates are known for their stereospecificity. The following studies show that l-codeine was active in the mouse tail-flick test as well as in the hot plate test whether given p.o. or s.c. The ED50 in the first test was 4.09 mg/kg s.c. (2.01-8.34 mg/ kg) and 13.41 mg/kg p.o. (6.91-26.0 mg/kg). In the second antinociceptive test, the ED50 was 20.66 mg/kg s.c. (11.52-37.08 mg/kg) and 20.47 mg/kg p.o. (14.63-28.57 mg/kg). The d-isomer of codeine was inactive ina both tests up to 100 mg/kg but caused hyperexcitability, convulsions and ultimately death. Although l-codeine was more potent than d-codeine inhibiting the cough reflex in the anesthetized cat, the d-compound did have good activity. The ED50 of the l-isomer was 0.27 mg/kgi.v. (0.14-0.47 mg/kg) and that of the d-isomer was 1.61 mg/kg i.v. (0.98-2.65 mg/kg). In these animals, l-codeine did not significantly affect the cardiovascular parameters at the doses tested, whereas d-codeine caused a significant but transient decrease in the blood pressure and heart rate. The specific and nonspecific properties of d- and l-codeine were further delineated in the opiate receptor binding assay. l-Codeine inhibited the stereospecific binding of 2.2 x 10(-9) M [3H]dihydromorphine in mouse brain homogenate with the IC50 being 1.6 x 10(-5) M (1.2 x 10(-5)--2.0 x 10(-5) M). d-Codeine had no effect up to 10(-4) M. 相似文献
62.
Pain attitudes and knowledge among RNs, pharmacists, and physicians on an inpatient oncology service 总被引:1,自引:0,他引:1
Xue Y Schulman-Green D Czaplinski C Harris D McCorkle R 《Clinical journal of oncology nursing》2007,11(5):687-695
Patients with cancer often experience pain, yet studies continue to document inadequate and inappropriate assessment and management of cancer-related pain. This study aimed to evaluate the attitudes and knowledge of inpatient oncology healthcare providers toward pain management by surveying nurses, pharmacists, and physicians working on the inpatient oncology units at an academic medical center. Healthcare providers generally reported positive attitudes toward pain management but were deficient in their knowledge of pain management. The authors suggest that pharmacists become more integral members of palliative care teams and actively participate in rounds. A need exists for educational programs in pain management for healthcare providers, especially for those who do not routinely care for patients with cancer. 相似文献
63.
Effect of a hospital-associated urinary tract infection reduction policy on general surgery patients
Sheena K. Harris Erica L. Mitchell Michael R. Lasarev Fouad Attia John G. Hunter Brett C. Sheppard 《American journal of surgery》2018,215(4):658-662
Background
Hospital-associated UTI rates in surgery patients have not improved despite recommendations for reducing indwelling catheter days.Methods
We performed a retrospective review of institutional NSQIP general surgery patient data, 2006–2015. During this time, a UTI-reduction policy was implemented. Demographics, HA-UTI incidence, CA-UTI incidence, indwelling catheter days, straight catheterization rates, and mortality were examined.Results
Females had significantly higher risk of HA-UTI. There was no significant change in HA-UTI (X12?=?0.02, p?=?.878) or indwelling catheter days (5.18?±?1.12 days v 3.73?±?0.39 days, p?=?.23). Straight catheterizations among those with HA-UTI increased (0.04?±?0.04 v 0.32?±?0.12, p?=?.029). There was no change in CA-UTI (1.38 v 1.11 CAUTI/1000 patient hospital-days P?=?.555) or in initial indwelling catheter days of patients with CA-UTI (7.2 SD 8.89 v 47.0 SD 7.04 days P?=?.961) after policy implementation.Conclusions
The reduction policy increased the number of straight catheterizations for patients developing HA-UTI, but did not reduce the number of initial indwelling catheter days, HA-UTI rates, or CA-UTI rates. 相似文献64.
65.
66.
67.
Tokiko Hamasaki René Pelletier Daniel Bourbonnais Patrick Harris Manon Choinière 《Journal of hand therapy》2018,31(2):215-226
Study Design
Literature review.Introduction
Pain is a subjective experience that results from the modulation of nociception conveyed to the brain via the nervous system. Perception of pain takes place when potential or actual noxious stimuli are appraised as threats of injury. This appraisal is influenced by one's cognitions and emotions based on her/his pain-related experiences, which are processed in the forebrain and limbic areas of the brain. Unarguably, patients' psychological factors such as cognitions (eg, pain catastrophizing), emotions (eg, depression), and pain-related behaviors (eg, avoidance) can influence perceived pain intensity, disability, and treatment outcomes. Therefore, hand therapists should address the patient pain experience using a biopsychosocial approach. However, in hand therapy, a biomedical perspective predominates in pain management by focusing solely on tissue healing.Purpose of the Study
This review aims to raise awareness among hand therapists of the impact of pain-related psychological factors.Methods and Results
This literature review allowed to describe (1) how the neurophysiological mechanisms of pain can be influenced by various psychological factors, (2) several evidence-based interventions that can be integrated into hand therapy to address these psychological issues, and (3) some approaches of psychotherapy for patients with maladaptive pain experiences.Discussion and Conclusion
Restoration of sensory and motor functions as well as alleviating pain is at the core of hand therapy. Numerous psychological factors including patients' beliefs, cognitions, and emotions alter their pain experience and may impact on their outcomes. Decoding the biopsychosocial components of the patients' pain is thus essential for hand therapists. 相似文献68.
69.
Dan Wu Jonathan M. Han Xin Yu Avery J. Lam Romy E. Hoeppli Anne M. Pesenacker Qing Huang Virginia Chen Cate Speake Ekua Yorke Nam Nguyen Sharadh Sampath David Harris Megan K. Levings 《European journal of immunology》2019,49(2):336-347
Obesity‐associated visceral adipose tissue (AT) inflammation promotes insulin resistance and type 2 diabetes (T2D). In mice, lean visceral AT is populated with anti‐inflammatory cells, notably regulatory T cells (Tregs) expressing the IL‐33 receptor ST2. Conversely, obese AT contains fewer Tregs and more proinflammatory cells. In humans, however, there is limited evidence for a similar pattern of obesity‐associated immunomodulation. We used flow cytometry and mRNA quantification to characterize human omental AT in 29 obese subjects, 18 of whom had T2D. Patients with T2D had increased proportions of inflammatory cells, including M1 macrophages, with positive correlations to body mass index. In contrast, Treg frequencies negatively correlated to body mass index but were comparable between T2D and non‐T2D individuals. Compared to human thymic Tregs, omental AT Tregs expressed similar levels of FOXP3, CD25, IKZF2, and CTLA4, but higher levels of PPARG, CCR4, PRDM1, and CXCL2. ST2, however, was not detectable on omental AT Tregs from lean or obese subjects. This is the first comprehensive investigation into how omental AT immunity changes with obesity and T2D in humans, revealing important similarities and differences to paradigms in mice. These data increase our understanding of how pathways of immune regulation could be targeted to ameliorate AT inflammation in humans. 相似文献
70.
York Pei Young-Hwan Hwang John Conklin Jamie L. Sundsbak Christina M. Heyer Winnie Chan Kairong Wang Ning He Anand Rattansingh Mostafa Atri Peter C. Harris Masoom A. Haider 《Journal of the American Society of Nephrology : JASN》2015,26(3):746-753
The clinical use of conventional ultrasonography (US) in autosomal dominant polycystic kidney disease (ADPKD) is currently limited by reduced diagnostic sensitivity, especially in at-risk subjects younger than 30 years of age. In this single-center prospective study, we compared the diagnostic performance of MRI with that of high-resolution (HR) US in 126 subjects ages 16–40 years born with a 50% risk of ADPKD who underwent both these renal imaging studies and comprehensive PKD1 and PKD2 mutation screening. Concurrently, 45 healthy control subjects without a family history of ADPKD completed the same imaging protocol. We analyzed 110 at-risk subjects whose disease status was unequivocally defined by molecular testing and 45 unaffected healthy control subjects. Using a total of >10 cysts as a test criterion in subjects younger than 30 years of age, we found that MRI provided both a sensitivity and specificity of 100%. Comparison of our results from HR US with those from a previous study of conventional US using the test criterion of a total of three or more cysts found a higher diagnostic sensitivity (approximately 97% versus approximately 82%) with a slightly decreased specificity (approximately 98% versus 100%) in this study. Similar results were obtained in test subjects between the ages of 30 and 40 years old. These results suggest that MRI is highly sensitive and specific for diagnosis of ADPKD. HR US has the potential to rival the diagnostic performance of MRI but is both center- and operator-dependent. 相似文献