全文获取类型
收费全文 | 113821篇 |
免费 | 10816篇 |
国内免费 | 1216篇 |
专业分类
耳鼻咽喉 | 546篇 |
儿科学 | 2564篇 |
妇产科学 | 1861篇 |
基础医学 | 8931篇 |
口腔科学 | 6143篇 |
临床医学 | 17896篇 |
内科学 | 9515篇 |
皮肤病学 | 667篇 |
神经病学 | 5422篇 |
特种医学 | 2898篇 |
外科学 | 14343篇 |
综合类 | 11006篇 |
现状与发展 | 3篇 |
一般理论 | 90篇 |
预防医学 | 34553篇 |
眼科学 | 343篇 |
药学 | 4187篇 |
88篇 | |
中国医学 | 1487篇 |
肿瘤学 | 3310篇 |
出版年
2024年 | 232篇 |
2023年 | 2761篇 |
2022年 | 2761篇 |
2021年 | 5459篇 |
2020年 | 5430篇 |
2019年 | 5215篇 |
2018年 | 4819篇 |
2017年 | 4491篇 |
2016年 | 4565篇 |
2015年 | 4621篇 |
2014年 | 7301篇 |
2013年 | 9230篇 |
2012年 | 6370篇 |
2011年 | 7067篇 |
2010年 | 5423篇 |
2009年 | 5753篇 |
2008年 | 5590篇 |
2007年 | 5649篇 |
2006年 | 5022篇 |
2005年 | 4235篇 |
2004年 | 3587篇 |
2003年 | 3077篇 |
2002年 | 2297篇 |
2001年 | 2164篇 |
2000年 | 2020篇 |
1999年 | 1486篇 |
1998年 | 1240篇 |
1997年 | 1070篇 |
1996年 | 875篇 |
1995年 | 716篇 |
1994年 | 648篇 |
1993年 | 606篇 |
1992年 | 512篇 |
1991年 | 435篇 |
1990年 | 361篇 |
1989年 | 297篇 |
1988年 | 336篇 |
1987年 | 249篇 |
1986年 | 246篇 |
1985年 | 244篇 |
1984年 | 186篇 |
1983年 | 107篇 |
1982年 | 152篇 |
1981年 | 128篇 |
1980年 | 130篇 |
1979年 | 129篇 |
1978年 | 112篇 |
1977年 | 106篇 |
1976年 | 80篇 |
1973年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
《Value in health》2022,25(12):1958-1966
ObjectivesNational health technology assessments (HTAs) across Europe show differences in evidentiary requirements from assessments by the European Medicines Agency (EMA), affecting time to patient access for drugs after marketing authorization. This article analyzes the differences between EMA and HTA bodies’ evidentiary requirements for oncology drugs and provides recommendations on potential further alignment to minimize and optimally manage the remaining differences.MethodsInterviews were performed with representatives and drug assessment experts from EMA and HTA bodies to identify evidentiary requirements for several subdomains and collect recommendations for potentially more efficiently addressing differences. A comparative analysis of acceptability of the evidence by EMA and the HTA bodies and for potential further alignment between both authorities was conducted.ResultsAcceptability of available evidence was higher for EMA than HTA bodies. HTA bodies and EMA were aligned on evidentiary requirements in most cases. The subdomains showing notable differences concerned the acceptance of limitation of the target population and extrapolation of target populations, progression-free survival and (other) surrogate endpoints as outcomes, cross-over designs, short trial duration, and clinical relevance of the effect size. Recommendations for reducing or optimally managing differences included joint early dialogues, joint relative effectiveness assessments, and the use of managed entry agreements.ConclusionsDifferences between assessments of EMA and HTA bodies were identified in important areas of evidentiary requirements. Increased alignment between EMA and HTA bodies is suggested and recommendations for realization are discussed. 相似文献
104.
Sandrine F. Chebekoue 《Journal of occupational and environmental hygiene》2019,16(4):308-319
This study aimed at deriving occupational thresholds of toxicological concern for inhalation exposure to systemically-acting organic chemicals using predicted internal doses. The latter were also used to evaluate the quantitative relationship between occupational exposure limit and internal dose. Three internal dose measures were identified for investigation: (i) the daily area under the venous blood concentration vs. time curve, (ii) the daily rate of the amount of parent chemical metabolized, and (iii) the maximum venous blood concentration at the end of an 8-hr work shift. A dataset of 276 organic chemicals with 8-hr threshold limit values-time-weighted average was compiled along with their molecular structure and Cramer classes (Class I: low toxicity, Class II: intermediate toxicity, Class III: suggestive of significant toxicity). Using a human physiologically-based pharmacokinetic model, the three identified dose metrics were predicted for an 8-hr occupational inhalation exposure to the threshold limit value for each chemical. Distributional analyses of the predicted dose metrics were performed to identify the percentile values corresponding to the occupational thresholds of toxicological concern. Also, simple linear regression analyses were performed to evaluate the relationship between the 8-hr threshold limit value and each of the predicted dose metrics, respectively. No threshold of toxicological concern could be derived for class II due to few chemicals. Based on the daily rate of the amount of parent chemical metabolized, the proposed internal dose-based occupational thresholds of toxicological concern were 5.61?×?10?2 and 9?×?10?4 mmol/d at the 10th percentile level for classes I and III, respectively, while they were 4.55?×?10?1 and 8.5?×?10?3 mmol/d at the 25th percentile level. Even though high and significant correlations were observed between the 8-hr threshold limit values and the predicted dose metrics, the one with the rate of the amount of chemical metabolized was remarkable regardless of the Cramer class (r2 = 0.81; n = 276). The proposed internal dose-based occupational thresholds of toxicological concern are potentially useful for screening-level assessments as well as prioritization within an integrated occupational risk assessment framework. 相似文献
105.
《Research in social & administrative pharmacy》2022,18(9):3699-3703
As one of the overreaching goals of Healthy People 2030, addressing the social determinants of health (SDOH) to reduce health disparities is a nationwide concern, with objectives informed by interdisciplinary teams of experts. However, there remains much discussion regarding the roles of healthcare providers in addressing SDOH. While current guidance suggests that all members of the healthcare team must be empowered to address SDOH, current guidance explicitly references physicians, nurses, social workers and staff, and do not specifically include pharmacists. While pharmacists are taught about the impact of SDOH in pharmacy curricula, actionable strategies for pharmacists to address SDOH in practice have not been clearly outlined. Pharmacists have multifaceted interactions with patients and may be influential in meeting individual patient needs, identifying social risk factors, and addressing upstream causes of health disparities. This paper proposes a framework for the role of pharmacists in addressing the SDOH through strategies at the patient, practice, and community levels. The concepts presented in this paper are meant to serve as a launch point for discussion and to promote the inclusion of pharmacists in the conversations around sustainable efforts to achieve health equity. This framework is not intended to limit the scope of pharmacists in addressing SDOH – on the contrary, it is our hope that this outline may be used to expand the education of future healthcare professionals regarding their role in addressing the social determinants of health. 相似文献
106.
Thomas W. McDade Alexander V. Georgiev Christopher W. Kuzawa 《Evolution, Medicine, and Public Health》2016,2016(1):1-16
Immune defenses provide resistance against infectious disease that is critical to survival. But immune defenses are costly, and limited resources allocated to immunity are not available for other physiological or developmental processes. We propose a framework for explaining variation in patterns of investment in two important subsystems of anti-pathogen defense: innate (non-specific) and acquired (specific) immunity. The developmental costs of acquired immunity are high, but the costs of maintenance and activation are relatively low. Innate immunity imposes lower upfront developmental costs, but higher operating costs. Innate defenses are mobilized quickly and are effective against novel pathogens. Acquired responses are less effective against novel exposures, but more effective against secondary exposures due to immunological memory. Based on their distinct profiles of costs and effectiveness, we propose that the balance of investment in innate versus acquired immunity is variable, and that this balance is optimized in response to local ecological conditions early in development. Nutritional abundance, high pathogen exposure and low signals of extrinsic mortality risk during sensitive periods of immune development should all favor relatively higher levels of investment in acquired immunity. Undernutrition, low pathogen exposure, and high mortality risk should favor innate immune defenses. The hypothesis provides a framework for organizing prior empirical research on the impact of developmental environments on innate and acquired immunity, and suggests promising directions for future research in human ecological immunology. 相似文献
107.
《Biomaterials》2015
In normal tissue repair, macrophages exhibit a pro-inflammatory phenotype (M1) at early stages and a pro-healing phenotype (M2) at later stages. We have previously shown that M1 macrophages initiate angiogenesis while M2 macrophages promote vessel maturation. Therefore, we reasoned that scaffolds that promote sequential M1 and M2 polarization of infiltrating macrophages should result in enhanced angiogenesis and healing. To this end, we first analyzed the in vitro kinetics of macrophage phenotype switch using flow cytometry, gene expression, and cytokine secretion analysis. Then, we designed scaffolds for bone regeneration based on modifications of decellularized bone for a short release of interferon-gamma (IFNg) to promote the M1 phenotype, followed by a more sustained release of interleukin-4 (IL4) to promote the M2 phenotype. To achieve this sequential release profile, IFNg was physically adsorbed onto the scaffolds, while IL4 was attached via biotin-streptavidin binding. Interestingly, despite the strong interactions between biotin and streptavidin, release studies showed that biotinylated IL4 was released over 6 days. These scaffolds promoted sequential M1 and M2 polarization of primary human macrophages as measured by gene expression of ten M1 and M2 markers and secretion of four cytokines, although the overlapping phases of IFNg and IL4 release tempered polarization to some extent. Murine subcutaneous implantation model showed increased vascularization in scaffolds releasing IFNg compared to controls. This study demonstrates that scaffolds for tissue engineering can be designed to harness the angiogenic behavior of host macrophages towards scaffold vascularization. 相似文献
108.
Theodore M. Brasky Roberta M. Ray Sandi L. Navarro Jeannette M. Schenk Alison M. Newton Marian L. Neuhouser 《International journal of cancer. Journal international du cancer》2020,147(5):1374-1384
We and others have reported associations between B vitamins principally involved in one-carbon metabolism and increased lung cancer risk; however, results for women have been inconsistent. Here we report on the association of supplemental vitamins B6, folic acid and B12 intake and lung cancer risk using data from the Women's Health Initiative (WHI) study of postmenopausal women. Between 1993 and 1998, 161,808 women were recruited to participate in the WHI at 40 clinical centers in the US. After exclusions, 159,232 women were available for analysis and followed prospectively for an average of 18.3 years. Among them, 3,836 incident lung cancer cases were diagnosed. At baseline, supplemental B vitamins from multivitamins, vitamin mixtures and individual supplements were assessed. Adjusted Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between supplemental B vitamin intake and lung cancer risk. Relative to no intake, women who took ≥50 mg/day of vitamin B6 had 16% (HR 0.84, 95% CI: 0.71–0.99) reduced lung cancer risk. Associations did not differ significantly by smoking status or lung cancer histology. Intakes of folic acid and vitamin B12 were not associated with risk. There is a need for replication of our findings from other large, prospective studies with similar high-quality measurement of supplement intakes before any recommendations can be made at present on B6 supplementation for lung cancer prevention in women. 相似文献
109.
《Clinical Lymphoma, Myeloma & Leukemia》2020,20(7):415-421
Myelofibrosis (MF) is a BCR-ABL1− myeloproliferative neoplasm that arises from hematopoietic stem and progenitor cells frequently harboring a somatic driver mutation in 1 of 3 genes: JAK2, CALR, or MPL. The pathologic features of this hematologic malignancy include myeloproliferation, diffuse bone marrow fibrosis, and overactivation of the JAK-STAT pathway, resulting in enhanced inflammatory cytokine release. The common clinical manifestations of MF include systemic symptoms, abnormal peripheral blood count levels, and splenomegaly. However, it has become increasingly appreciated that significant clinical heterogeneity exists among patients with MF. Two distinct MF clinical phenotypes include the myeloproliferative and myelodepletive phenotype, with peripheral blood counts being the main discerning feature. Patients with the myeloproliferative phenotype will present with elevated peripheral blood counts and often experience significant constitutional symptoms and progressive splenomegaly. In contrast, patients with the myelodepletive phenotype will have low peripheral blood counts and will frequently require transfusion support. Current frontline therapies for MF, include ruxolitinib and fedratinib, which can exacerbate cytopenias and thereby pose an impediment to effective treatment of the myelodepletive patient. The present review discusses the clinical and prognostic implications of the myelodepletive phenotype and the therapeutic options and limitations for this subset of patients, representing an unmet clinical need. 相似文献
110.
Anna Grace Tribble Phillip Summers Haiying Chen Sara A. Quandt 《Archives of environmental & occupational health》2016,71(6):309-316
The jobs of Latino manual laborers place their mental and physical health at risk. This study evaluates the associations among musculoskeletal pain, mental health, and work organization in Latino manual laborers. Farmworkers and nonfarmworkers (n = 189) in North Carolina were interviewed for self-reported musculoskeletal pain, depressive symptoms, stress, work safety climate, and precarious job status. More nonfarmworkers than farmworkers had neck and shoulder pain, but they did not differ in other areas of musculoskeletal pain. Depressive symptoms had a significant association with neck and shoulder pain (p < .05). Precariousness had a significant association with back pain (p < .05). Farmworker participants had H-2A visas and were afforded some protection compared to nonfarmworker manual workers. Research is needed to improve policy that relieves pain and improves mental health for all Latino manual workers. 相似文献