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   2474篇
  免费   212篇
  国内免费   6篇
耳鼻咽喉   6篇
儿科学   56篇
妇产科学   45篇
基础医学   423篇
口腔科学   11篇
临床医学   262篇
内科学   582篇
皮肤病学   54篇
神经病学   270篇
特种医学   47篇
外科学   302篇
综合类   4篇
一般理论   1篇
预防医学   184篇
眼科学   32篇
药学   164篇
中国医学   1篇
肿瘤学   248篇
  2024年   6篇
  2023年   56篇
  2022年   70篇
  2021年   177篇
  2020年   78篇
  2019年   113篇
  2018年   162篇
  2017年   90篇
  2016年   106篇
  2015年   111篇
  2014年   129篇
  2013年   152篇
  2012年   272篇
  2011年   275篇
  2010年   118篇
  2009年   79篇
  2008年   144篇
  2007年   143篇
  2006年   100篇
  2005年   78篇
  2004年   50篇
  2003年   38篇
  2002年   23篇
  2001年   9篇
  2000年   8篇
  1999年   10篇
  1998年   5篇
  1997年   5篇
  1996年   3篇
  1995年   7篇
  1994年   8篇
  1992年   9篇
  1991年   10篇
  1990年   4篇
  1989年   2篇
  1988年   3篇
  1987年   4篇
  1986年   4篇
  1985年   2篇
  1984年   2篇
  1983年   2篇
  1981年   2篇
  1970年   2篇
  1928年   1篇
  1927年   2篇
  1926年   1篇
  1925年   1篇
  1923年   1篇
  1919年   1篇
  1915年   1篇
排序方式: 共有2692条查询结果,搜索用时 0 毫秒
41.
42.
Lorente N  Henry E  Fugon L  Yomb Y  Carrieri MP  Eboko F  Spire B 《AIDS care》2012,24(8):1020-1027
In low- and middle-income countries, men who have sex with men (MSM) are 19 times more likely to be HIV positive compared with background populations. Criminalisation and social rejection of homosexuality in most sub-Saharan African countries reinforce stigma and exclude MSM from prevention activities, including HIV testing. This paper's purpose is to identify factors associated with never having been HIV tested (NHT), among a sample of Cameroonian MSM. In 2008, a community-based study was conducted in Douala, the economic capital city of Cameroon, by a local NGO Alternatives-Cameroun, recruiting participants through the snowball technique and administering a questionnaire during face-to-face interviews. Proximity to HIV was investigated according to the following criteria: knowing at least one person living with HIV and having been exposed to HIV prevention interventions. NHT was defined as reporting to have never been HIV tested. A logistic regression was used to identify factors associated with NHT. Among the 165 MSM of our study group who reported that they were not HIV positive, 19% reported NHT. Factors independently associated with NHT were as follows: being younger, being Muslim, not having a steady male partner, not knowing any person living with HIV and never having been exposed to HIV prevention interventions. In this MSM population, a small proportion reported that they had never been HIV tested and among these, the percentage was higher among individuals not in proximity to HIV. Despite the hostile context of sub-Saharan African countries towards MSM, local and national HIV testing campaigns to date may have played a substantial role in raising HIV awareness in the MSM population living in Douala, and peer-based counselling may have educated those in contact with Alternatives-Cameroun regarding the positive value of HIV testing. This result is a further argument for continuing community-based prevention and extending it to difficult-to-reach MSM.  相似文献   
43.
It has been suggested that treatment with adequate dose titration of pegvisomant, a GH antagonist, up to a maximum of 40 mg daily, can achieve IGF-1 normalisation in virtually all patients with acromegaly. On the other hand, temozolomide (TMZ), an alkylating cytostatic agent, has been reported to reduce pituitary tumour size and hormone hypersecretion in a small number of aggressive pituitary macroadenomas. In this paper we report the case of a patient resistant to very high doses of pegvisomant used in combination with somatostatin analogs (SSA) and to TMZ therapy. The patient, initially a 22 year-old man with an invasive GH-secreting pituitary macroadenoma (IGF-1, 371% upper limit of normal), had active acromegaly despite a repeat transsphenoidal surgery followed by radiotherapy and SSA (octreotide 800 μg sc daily) (IGF-1, 262% ULN). In combination with SSA, pegvisomant was started at 20 mg daily and doses were titrated up to 60 mg daily. IGF-1 was moderately reduced and stabilized at 200% ULN after 1 year of treatment. Serum pegvisomant level was 30,500 ng/l, the denaturalized GHBP concentration 1,120 pM and the endogenous GH level was 220 μg/l. Pegvisomant was stopped and TMZ therapy was given for 5 cycles. However, the patient reported an increase of acromegaly symptoms and the serum IGF-1 was raised to the same level prior to pegvisomant therapy. Consequently, pegvisomant was tried again with doses up to 100 mg daily finally resulting in normalisation of serum IGF-1 level and improvement of acromegaly symptoms and patient well-being. We conclude that in some patients with severe acromegaly refractory to multimodal therapy, biochemical control may be difficult to attain with conventional doses of pegvisomant or TMZ therapy.  相似文献   
44.

Background

Whereas palliative chemotherapy offers a median survival of approximately 10 months in advanced gastric and junctional adenocarcinoma (AGJA), the survival impact of primary tumor resection is controversial. Our purpose was to identify which AGJA patients benefit from palliative resection.

Methods

In 3,202 AGJA patients scheduled for surgery in 21 French centers between 1997 and 2010, prognostic factors were identified in palliative group and the impact of each combination of these factors on survival was studied.

Results

Surgery was defined as palliative due to solid organ metastasis (5.6 %), localized (4.6 %) or diffuse (2.3 %) peritoneal carcinomatosis (PC), or incomplete tumoral resection (12.8 %). Median survival of AGJA patients resected with a palliative intent (n = 677) was longer than in nonresected patients (n = 532; 11.9 vs. 8.5 months, P < 0.001). Multivariable analyses identified ASA score III-IV (P < 0.001) as a predictor of postoperative mortality and solid organ metastasis (P = 0.009), localized PC (P = 0.004), diffuse PC (P = 0.046), and signet ring cell histology (SRC; P = 0.02) as predictors of survival. Only ASA I–II patients with incomplete resection without metastasis or PC, one site solid organ metastasis without PC, or localized PC without SRC had a survival benefit after palliative surgery with median survivals from 12.0 to 18.3 months. Nonresected ASA I–II patients with same risk factors had median survivals from 3.5 to 8.8 months (P < 0.05 for each).

Conclusions

In AGJA, patient and tumor-related factors should be used to select candidates for palliative surgery in association with chemotherapy.  相似文献   
45.
46.
Introduction: Bacterial respiratory tract infections (RTIs) are increasingly difficult to treat due to evolving antibiotic resistance. In this context, bacteriophages (or phages) are part of the foreseen alternatives or combination therapies. Delivering phages through the airways seems more relevant to accumulate these natural antibacterial viruses in proximity to their bacterial host, within the infectious site.

Areas covered: This review addresses the potential of phage therapy to treat RTIs and discusses preclinical and clinical results of phages administration in this context. Recent phage formulation and aerosolization attempts are also reviewed, raising technical challenges to achieve efficient pulmonary deposition via inhalation.

Expert opinion: Overall, the inhalation of phages as antibacterial treatment seems both clinically relevant and technically feasible. Several crucial points still need to be investigated, such as phage product pharmacokinetics and immunogenicity. Furthermore, given phage-specific features, appropriate regulatory and manufacturing guidelines will need to be defined. Finally, randomized controlled clinical trials should be carried out to establish phage therapy’s clinical positioning in the antimicrobial arsenal against RTIs.  相似文献   

47.
48.
Background: Given the increasing emphasis on community-based provision of palliative care and the view that good dying should occur at home, it is unsurprising that policy in many countries has started focusing on preventing hospital admissions at the end of life. However, little attention has been paid to the role of the emergency department (ED) in this regard, despite the fact that a high proportion of hospital admissions among patients with palliative care needs originate in the ED. This paper presents the next logical step in improving understanding of ED use within a palliative care context; as to determine what constitutes an avoidable ED presentation initially requires recognition of the reasons that such patients are presenting.

Methods: A systematic, narrative approach was used to appraise the relevant studies. From August to December 2014, electronic databases, gray literature and guidelines were searched, using MeSH headings and keywords. As it was anticipated that reasons for presentation would be differently described, all papers addressing presentations to the ED among patients with palliative care needs were identified; information regarding reasons for presentation were then examined.

Results: Twelve papers ultimately met the inclusion criteria and were accessible. The ‘reason’ for a patient's presentation was largely defined as their ‘presenting complaint’ or ‘underlying diagnosis.’ There was consistency in the studies in this respect; the majority found that people with lung cancer and those experiencing distressing respiratory symptoms were most likely the present to the ED. Subsequently, pain and gastrointestinal symptoms such as nausea and vomiting were uniformly found to be most common. The three prospective studies gathered information about reason for presentation from the patient perspective using structured questionnaires, but no study collected qualitative data from patients and families.

Discussion: This systematic narrative review is the first to explore reasons for ED presentation among patients with palliative care needs. However, the data does not facilitate a detailed discussion about the difficulties that this population of patients face, and whether they may be best managed in an acute or community setting. A deep understanding of the perspectives of patients is urgently needed, so as to both understand their reasons for presentation and implement relevant patient-directed changes in service provision.  相似文献   

49.
Much research has found that exposure to certain types of media portrayals of women can be related to body image concerns among women. The current paper focuses on the impact of certain messages on pregnant and postpartum women. These women are rarely examined in a media research context but are particularly vulnerable to body image concerns. This experimental study involved 192 pregnant or postpartum women who read a magazine containing glamorized media portrayals of pregnant/postpartum women or a control magazine. Pregnant women reported lower body image after only five minutes of exposure to the magazine with pregnant/postpartum women compared to the control group. There was no immediate effect on postpartum women. Implications for the media industry, health professionals, and women are discussed.  相似文献   
50.

Purpose

To analyze trends in second primary cancer (SPC) incidence by using a case-mix approach to standardize on first cancer site distribution.

Methods

Cases registered by 13 French cancer registries between 1989 and 2010 and followed-up until June 2013 were included. The person-year approach was used to compute standardized incidence ratios (SIRs) of metachronous SPC. Usual SIRs and cancer site–specific weighted SIRs called “case-mix SIRs” (cmSIRs) were estimated by sex and calendar period of first cancer diagnosis. Calendar trends in SIRs and cmSIRs were compared.

Results

More than 2.9 million person-years at risk were included. Among males, SIRs dropped from 1.49 to 1.23 between 1989–1994 and 2005–2010, while cmSIRs decreased from 1.40 to 1.27. This difference seems mainly related to a stronger representation of prostate cancers (at lower risk of SPC) and a weaker contribution of bladder and head and neck cancers (at higher risk of SPC) in recent periods of diagnosis. Among females, both SIRs and cmSIRs have remained stable at around 1.22 and 1.21, respectively.

Conclusions

The cmSIR is an indicator that is not influenced by changes in first cancer site distribution. Its use should be encouraged to assess second cancer incidence control.  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