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   3087872篇
  免费   216292篇
  国内免费   4449篇
耳鼻咽喉   43210篇
儿科学   100210篇
妇产科学   83145篇
基础医学   450268篇
口腔科学   85764篇
临床医学   278400篇
内科学   591137篇
皮肤病学   68654篇
神经病学   240725篇
特种医学   117288篇
外国民族医学   676篇
外科学   464414篇
综合类   63137篇
现状与发展   13篇
一般理论   1044篇
预防医学   235519篇
眼科学   72189篇
药学   235373篇
  18篇
中国医学   6537篇
肿瘤学   170892篇
  2019年   24421篇
  2018年   34026篇
  2017年   25911篇
  2016年   29170篇
  2015年   32786篇
  2014年   45986篇
  2013年   68866篇
  2012年   94574篇
  2011年   100684篇
  2010年   59817篇
  2009年   56284篇
  2008年   94279篇
  2007年   100671篇
  2006年   101599篇
  2005年   98280篇
  2004年   94129篇
  2003年   90752篇
  2002年   87831篇
  2001年   145908篇
  2000年   150075篇
  1999年   125928篇
  1998年   35437篇
  1997年   31143篇
  1996年   31454篇
  1995年   29575篇
  1994年   27213篇
  1993年   25665篇
  1992年   96980篇
  1991年   94307篇
  1990年   92444篇
  1989年   88943篇
  1988年   81539篇
  1987年   79942篇
  1986年   75048篇
  1985年   71545篇
  1984年   52939篇
  1983年   44986篇
  1982年   26251篇
  1979年   48447篇
  1978年   34071篇
  1977年   28974篇
  1976年   26996篇
  1975年   29534篇
  1974年   35035篇
  1973年   33525篇
  1972年   31693篇
  1971年   29948篇
  1970年   27601篇
  1969年   26415篇
  1968年   23982篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
ObjectiveTo assess for the presence of gastric dysmotility in familial and sporadic Parkinson disease (PD).Methods10 subjects with familial Parkinson disease (fPD), 35 subjects with sporadic Parkinson disease (sPD), and 15 controls, all from academic tertiary care movement disorders centers, were studied. fPD was defined as the presence of at least 2 affected individuals within 2–3 consecutive generations in a family. Molecular genetic analysis has not revealed, thus far, any known genomic abnormality in these families. Gastric emptying was assessed by dynamic abdominal scintigraphy over 92 min following ingestion of a solid meal containing 99mTc-labeled colloid of 40 MBq activity. The main outcome measures were gastric emptying half-time and radiotracer activity over the gastric area at 46 and at 92 min.ResultsGastric emptying time was delayed in 60% of subjects with PD. In comparison to mean t1/2 of 38 ± 7 min in controls, mean t1/2 was 58 ± 25 min in fPD (p = 0.02) and 46 ± 25 min in sPD (p = 0.10). Both fPD and sPD groups included subjects with delayed gastric emptying at an early stage of disease.ConclusionsPatients with fPD showed significantly delayed gastric emptying in comparison to normal age-matched individuals. Further studies of gastrointestinal dysfunction in PD, particularly fPD, are warranted.  相似文献   
992.
993.
994.
AimsLocal coronary and systemic inflammation is pronounced in patients with diabetes mellitus (DM). Intracoronary thermography detects local inflammation and C-reactive protein (CRP) is a marker of systemic inflammation. We investigated whether or not, in patients with DM, thermal heterogeneity of culprit lesions (CLs) correlates with that of non-culprit lesions (NCLs) and with systemic inflammation.MethodsWe included DM patients who had two angiographically significant lesions and were undergoing percutaneous coronary intervention. We measured the temperature difference (ΔT) between the lesion and proximal vessel wall.ResultsWe included 104 (n = 208 lesions) patients: 32 (n = 64 lesions) had DM and 72 (n = 144 lesions) were non-DM (control group). ΔT was increased in DM in both CLs and NCLs (CLs: DM = 0.12 ± 0.06 °C; no DM = 0.06 ± 0.04 °C; P < 0.01 versus NCLs: DM = 0.13 ± 0.08 °C versus no DM = 0.06 ± 0.05 °C; P < 0.01). Patients with DM had similar ΔT in CLs and NCLs (P = 0.49). A linear correlation was detected between heat production in all lesions and CRP (R = 0.45; P < 0.01), which was attributed to the correlation of ΔT in lesions of patients with DM and CRP (R = 0.32; P < 0.01). In lesions of patients with low CRP, a greater rate of discrepancy was found, as 100% of lesions in patients with DM versus 66.1% of lesions of patients without DM had a high ΔT in one or both lesions (P < 0.01).ConclusionIn patients with DM, local inflammatory activation is diffuse and correlates with systemic inflammation. However, low systemic inflammatory activation does not always predict an increase in local thermal heterogeneity.  相似文献   
995.
996.
Abstract: As the most prevalent pathogen among transplant patients, cytomegalovirus (CMV) affects up to three-quarters of all solid organ transplant recipients. While we have made great strides in preventing CMV infection and disease in the early post-transplant period, late CMV infection and indirect effects due to viral immunomodulation remain problematic. Changing immunosuppression practices, including the increasing use of T-cell depleting induction antibodies, have the potential to affect the risk for CMV infection and disease, even in the face of good prophylactic and preemptive therapy. The purpose of this review article is to discuss the impact of CMV infection on long-term allograft outcomes and to re-evaluate the risks and management strategies for prevention of CMV in the framework of evolving modern immunosuppressive strategies.  相似文献   
997.
998.
999.
Breast cancer is the female malignant neoplasia with the highest incidence in the industrialized world. Despite many undeniable therapeutic successes obtained, breast cancer still remains, however, a major health issue. In the last few years, thanks to aromatase inhibitors, the hormone therapy for oestrogen-dependent breast cancer has evolved in terms of efficacy and tolerability; at the same time, it has enabled us to better define the role of oestrogens in the etiopathogenesis of this tumour. Weight increase and obesity have been identified as the most important risk and prognostic factors for breast cancer in postmenopausal women. Several hypotheses have been proposed to explain the association of obesity with postmenopausal breast cancer. A more recent hypothesis suggests that adipocytes and their autocrine (paracrine and endocrine actions) are at the centre of such an etiopathogenetic mechanism. A better understanding of the main mechanisms that link together menopause, body-weight increase and hormone-dependent breast cancer is paramount to enable the identification of key molecules involved in the development of breast carcinoma and suggest new therapeutic options. The present review will discuss important findings on the therapeutic aspects of adipose tissue and adipokines as a target for treatment of hormone-dependent breast cancer.  相似文献   
1000.
This study evaluated the effects of tobacco Purchase, Use and Possession (PUP) laws on student perceptions of adolescent tobacco use within towns and schools. Twenty‐four towns were randomly assigned into two conditions, the experimental condition (E PUP) involved efforts to increase both PUP law enforcement and reduce minors' access to commercial sources of tobacco, whereas the control condition (C) focused only on efforts to reduce minors' access to commercial sources of tobacco. A hierarchical linear modeling analytical approach was selected due to the multilevel data and nested design. The present study found that over time, youth in the experimental PUP condition observed less youth tobacco usage at school and in their town, and perceived lower rates of tobacco among their peers at school and among friends than youth in the control condition. The findings suggest that PUP law enforcement might be used to strengthen community norms against youth tobacco use.  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