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   8960篇
  免费   2487篇
  国内免费   127篇
耳鼻咽喉   370篇
儿科学   191篇
妇产科学   251篇
基础医学   192篇
口腔科学   151篇
临床医学   2884篇
内科学   1659篇
皮肤病学   307篇
神经病学   684篇
特种医学   329篇
外科学   1293篇
综合类   360篇
现状与发展   2篇
预防医学   1700篇
眼科学   100篇
药学   198篇
  1篇
中国医学   99篇
肿瘤学   803篇
  2024年   61篇
  2023年   410篇
  2022年   115篇
  2021年   257篇
  2020年   486篇
  2019年   166篇
  2018年   557篇
  2017年   599篇
  2016年   615篇
  2015年   707篇
  2014年   706篇
  2013年   1035篇
  2012年   381篇
  2011年   329篇
  2010年   510篇
  2009年   627篇
  2008年   300篇
  2007年   231篇
  2006年   270篇
  2005年   187篇
  2004年   144篇
  2003年   109篇
  2002年   106篇
  2001年   178篇
  2000年   111篇
  1999年   149篇
  1998年   269篇
  1997年   285篇
  1996年   308篇
  1995年   243篇
  1994年   173篇
  1993年   117篇
  1992年   85篇
  1991年   81篇
  1990年   73篇
  1989年   92篇
  1988年   70篇
  1987年   56篇
  1986年   49篇
  1985年   52篇
  1984年   45篇
  1983年   43篇
  1982年   30篇
  1981年   44篇
  1980年   19篇
  1979年   10篇
  1978年   13篇
  1977年   15篇
  1976年   14篇
  1975年   9篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
111.
Cognitive Impairment (CI) screening is recommended for those engaged in harmful levels of alcohol use. However, there is a lack of evidence on implementation. This paper explores the barriers and facilitators to CI screening experienced across a service specifically for older drinkers. The findings draw on data gathered as part of an evaluation of a multilevel programme to reduce alcohol-related harm in adults aged 50 and over in five demonstration areas across the United Kingdom. It is based on qualitative interviews and focus groups with 14 service providers and 22 service users. Findings are presented thematically under the section headings: acceptability of screening, interpretation and making sense of screening and treatment options. It is suggested that engagement with CI screening is most likely when its fit with agency culture and its purpose is clear; where service providers have the technical skills to administer and discuss the results of screening with service users; and where those undertaking screening have had the opportunity to reflect on their own experience of being screened. Engagement with CI screening is also most likely where specific intervention pathways and engagement practices can be accessed to respond to assessed need.  相似文献   
112.
113.
Transgender (trans) women experience barriers to access to HIV care, which result in their lower engagement in HIV prevention, treatment and support relative to cisgender people living with HIV. Studies of trans women's barriers to HIV care have predominantly focused on perspectives of trans women, while barriers are most often described at provider, organisation and/or systems levels. Comparing perspectives of trans women and service providers may promote a shared vision for achieving health equity. Thus, this qualitative study utilised focus groups and semi-structured interviews conducted 2018–2019 to understand barriers and facilitators to HIV care from the perspectives of trans women (n = 26) and service providers (n = 10). Barriers endorsed by both groups included: (a) anticipated and enacted stigma and discrimination in the provision of direct care, (b) lack of provider knowledge of HIV care needs for trans women, (c) absence of trans-specific services/organisations and (d) cisnormativity in sexual healthcare. Facilitators included: (a) provision of trans-positive trauma-informed care, (b) autonomy and choice for trans women in selecting sexual health services and (c) models for trans-affirming systems change. Each theme had significant overlap, yet nuanced perspective, between trans women and service providers. Specific recommendations to improve HIV care access for trans women are discussed. These recommendations can be used by administrators and service providers alike to work collaboratively with trans women to reduce barriers and facilitators to HIV care and ultimately to achieve health equity for trans women.  相似文献   
114.
Lack of expression of the fragile X mental retardation protein (FMRP) results in mental retardation and macroorchidism, seen as the major pathological symptoms in fragile X patients. FMRP is a cytoplasmic RNA- binding protein which cosediments with the 60S ribosomal subunit. Recently, two proteins homologous to FMRP were discovered: FXR1 and FXR2. These novel proteins interact with FMRP and with each other and they are also associated with the 60S ribosomal subunit. Here, we studied the expression pattern of the three proteins in brain and testis by immunohistochemistry. In adult brain, FMR1, FXR1 and FXR2 proteins are coexpressed in the cytoplasm of specific differentiated neurons only. However, we observed a different expression pattern in fetal brain as well as in adult and fetal testis, suggesting independent functions for the three proteins in those tissues during embryonic development and adult life.   相似文献   
115.
Members of 183 families (biological parents and one adult offspring) completed questionnaires on their quantity and frequency of alcohol use, what they would consider a "normal" quantity-frequency of alcohol use, "problem" quantity-frequency of use, flushing after alcohol use, and other expected physiological and subjective responses to alcohol. Within individuals, own quantity-frequency of alcohol use was moderately negatively correlated with flushing after one drink or less ("fast flushing"), but more highly positively correlated with judged normal alcohol use and with expected subjective effects. Spouse resemblances were low for quantity-frequency of alcohol use and flushing, but high for alcohol use norms and expected physiological and subjective responses. Parent-offspring resemblances were low to moderate for own alcohol use and flushing, but moderate to high for expected physiological and subjective effects. These results were discussed in terms of the effects of genetically transmitted flushing after alcohol use and culturally transmitted alcohol norms and expectations on alcohol use.  相似文献   
116.
Case reports are presented on three patients treated for morbid obesity by vertical gastroplasty. Prior to surgery the patients had diabetes which required insulin, up to 200 units per day, or oral hypoglycaemics for its control. Six months after surgery the diabetes had been resolved in all three patients, and they were no longer dependent on medication. Subjective reports from the patients suggests that their quality of life improved significantly.  相似文献   
117.
A prospective study of biochemical changes after vertical banded gastroplasty for morbid obesity, in 94 patients (10 males and 84 females, ages ranging from 18 to 59 years) has been carried out. Liver function tests and electrolyte estimations were performed preoperatively, during hospitalisation for surgery, at 6 weeks and at 6 months postoperatively, and demonstrated no significant changes in liver function in these patients 6 months after surgery. The study concludes that there is no increase in the risk of liver damage or electrolyte disturbance after vertical gastroplasty, but that there may be subtle hepatic changes present as gall bladder disease developed in 18 patients postoperation (19%).  相似文献   
118.
  • • Recent research from America has confirmed that the quality of metabolic control achieved by people with insulin-dependent diabetes does influence the onset and progression of diabetic complications.
  • • More than ever before diabetic individuals now have good reasons for striving to attain as good a standard of diabetic control as is possible. Regular monitoring of diabetic status is essential if good control is to be achieved.
  • • This article will focus upon the concept of control and consider aspects of diabetic monitoring which may be undertaken either by patients or through professional services.
  • • Both direct and indirect monitoring methods will be discussed and strengths and weaknesses considered.
  相似文献   
119.
A retrospective study of 136 men undergoing forefoot amputation was done to test the hypothesis that preoperative toe pressure (TP) could predict the likelihood of wound healing. Demographic data included age, smoking history, diabetes mellitus (DM), hypertension, hyperlipidemia, and coronary artery disease. Clinical data included infection, preoperative arterial Doppler data, TP, wound disposition, concomitant revascularization (REV), and healing outcome. Among diabetics, no primary amputation healed with a preoperative TP <38 mm Hg. Among REV diabetics, no healing occurred with a TP <40 mm Hg after bypass, but no failures occurred either with a TP >68 mm Hg or an increase in TP >30 mm Hg after bypass. Nondiabetic patients exhibited no threshold TP values. Univariate analysis revealed that DM and REV were significantly different in the healed (N=83) vs. nonhealed (N=53) populations ( p =0.027 and 0.034). In healed patients, mean TP (71.8 ± 3.5 mm Hg SEM) was significantly higher than in nonhealed patients (45.1 ± 4.3 mm Hg SEM,p =0.000). Logistic regression analysis identified age >60 years (p =0.03), DM (p =0.003), preoperative TP ( p <0.001), and REV ( p <0.001) as significant independent predictors of forefoot amputation healing. Healing probability was calculated and plotted vs. TP for subpopulations based on age, DM, and REV status for both primary forefoot amputation and amputation concomitant with bypass. In this study population, therefore, preoperative TP appeared to be a useful clinical tool for predicting the healing potential of both primary forefoot amputations and amputations plus concomitant bypass for any given patient.  相似文献   
120.
Roecklein  BA; Torok-Storb  B 《Blood》1995,85(4):997-1005
A replication-defective recombinant retrovirus containing the human papilloma virus E6/E7 genes (LXSN-16 E6E7) was used to immortalize stromal cells from human marrow. The E6/E7 gene products interfere with the function of tumor-suppressor proteins p53 and Rb, respectively, thereby preventing cell cycle arrest without causing significant transformation. Twenty-seven immortalized clones designated HS-1 to HS- 27 were isolated, four of which are characterized in this report. Two cell lines, HS-5 and HS-21, appear to be fibroblastoid and secrete significant levels of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage-CSF (GM-CSF), macrophage-CSF (M-CSF), Kit ligand (KL), macrophage-inhibitory protein-1 alpha, interleukin-6 (IL-6), IL- 8, and IL-11. However, only HS-5 supports proliferation of hematopoietic progenitor cells when cocultured in serum-deprived media with no exogenous factors. Conditioned media (CM) from HS-5 promotes growth of myeloid colonies to significantly greater extent than a cocktail of recombinant factors containing 10 ng/mL of IL-1, IL-3, IL- 6, G-CSF, GM-CSF, and KL and 3 U of erythropoietin (Epo). Two additional clones, HS-23 and HS-27, resemble "blanket" cells, with an epithelioid morphology, and are much larger, broader, and flatter when compared with HS-5 and HS-21. These lines secrete low levels of growth factors and do not support proliferation of isolated progenitor cells in cocultures. CM from HS-23 and HS-27 also fail to support growth of myeloid colonies. Both HS-23 and HS-27 express relatively high levels of VCAM-1, yet HS-27 is the only line that supports the formation of "cobblestone" areas by isolated CD34+38lo cells. We hypothesize that HS- 5, HS-21, HS-23, and HS-27 represent functionally distinct components of the marrow microenvironment.  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