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   25930篇
  免费   1376篇
  国内免费   66篇
耳鼻咽喉   363篇
儿科学   2051篇
妇产科学   626篇
基础医学   2987篇
口腔科学   480篇
临床医学   1405篇
内科学   4804篇
皮肤病学   1005篇
神经病学   1152篇
特种医学   957篇
外科学   3887篇
综合类   918篇
一般理论   11篇
预防医学   1272篇
眼科学   1297篇
药学   2137篇
中国医学   147篇
肿瘤学   1873篇
  2023年   136篇
  2022年   298篇
  2021年   744篇
  2020年   415篇
  2019年   484篇
  2018年   703篇
  2017年   461篇
  2016年   671篇
  2015年   595篇
  2014年   933篇
  2013年   1095篇
  2012年   1547篇
  2011年   1650篇
  2010年   895篇
  2009年   719篇
  2008年   1245篇
  2007年   1325篇
  2006年   1135篇
  2005年   1083篇
  2004年   971篇
  2003年   891篇
  2002年   805篇
  2001年   725篇
  2000年   684篇
  1999年   599篇
  1998年   245篇
  1997年   179篇
  1996年   145篇
  1995年   136篇
  1994年   115篇
  1993年   130篇
  1992年   356篇
  1991年   390篇
  1990年   343篇
  1989年   358篇
  1988年   308篇
  1987年   277篇
  1986年   268篇
  1985年   279篇
  1984年   219篇
  1983年   181篇
  1979年   241篇
  1978年   158篇
  1977年   148篇
  1976年   135篇
  1975年   163篇
  1974年   154篇
  1973年   177篇
  1972年   138篇
  1971年   122篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Genetic polymorphisms in the methylene tetrahydrofolate reductase (MTHFR) gene have been associated with the development of acute leukemias and various malignancies. The role of MTHFR polymorphism in the development of pediatric acute lymphoblastic leukemia (ALL) has been extensively studied among north Indians in various settings, yet its association with acute leukemias remains unresolved. To evaluate the relationship between functional MTHFR polymorphisms, C677T and A1298C and possible effect on risk of ALL in adults and children in North Indian population by comparing them with healthy controls. DNA was isolated from peripheral blood of 184 ALL patients (33 adults, 151 children) and 155 controls and analyzed by a PCR-restriction fragment length polymorphism assay. The frequency of MTHFR 677CT and 1298 AC genotypes were significantly lower among adult ALL cases when compared to the controls. We found a 1.74-fold reduced risk of ALL in individuals with 1298AC polymorphic variant and a 9.17-fold decreased risk of adult ALL. However, no statistically significant difference was evident between the above polymorphisms and susceptibility to ALL in children. Polymorphisms in the MTHFR gene possibly modulate risk of ALL in north Indian adults but not in children, although larger studies are needed.  相似文献   
992.
Acute leukemia, secondary myelodysplasia and paroxysmal nocturnal hemoglobinuria evolving from severe aplastic anemia (AA) following immunosuppressive therapy are well recognized. However, severe AA occurring after complete remission of acute promyelocytic leukemia (APL) has been documented only once in 2009. We report a case of 30-year-old male diagnosed with APL who achieved complete cytogenetic remission with all-trans retinoic acid based induction regimen and developed severe AA few months later during maintenance therapy.  相似文献   
993.
Survival and outcomes have improved considerably among patients with juvenile dermatomyositis (JDM) in the west. However, mortality continues to be high in the developing world. There is paucity of literature on this aspect of JDM from developing countries. We reviewed case files of all patients with JDM registered in the Pediatric Rheumatology Clinic, Advanced Pediatrics Centre at the Post Graduate Institute of Medical Education and Research, Chandigarh, during the period 1993–2013. Seventy-six children were diagnosed to have inflammatory myopathy during this period. Of these, 63 had JDM, 3 had polymyositis while 10 had an overlap syndrome. We had reported 2 deaths out of 33 (8.3 %) patients with JDM in 2004, and over the last 9 years, we have encountered five more deaths in this group, thereby accounting for a mortality rate of 11.1 % (7/63) over two decades of follow-up. In these five children now being described, the mean duration between onset of symptoms and institution of appropriate therapy was 9.2 months. Four children (80 %) had severe muscle weakness needing nasogastric tubes at the onset, three (60 %) had cutaneous ulcers and three (60 %) had superadded infections. Two children (40 %) had gastrointestinal vasculitis and one of these developed an intestinal perforation. Three patients (60 %) had progressive pulmonary disease and air leak was identified in two of them. Although the prognosis for survival in JDM has steadily improved, in our experience the disease remains a serious illness and still carries significant mortality in the context of a developing country.  相似文献   
994.
This overview provides a guideline for the management of stable ischemic heart disease. It represents the work of a primary and secondary panel of participants from across Canada who achieved consensus on behalf of the Canadian Cardiovascular Society. The suggestions and recommendations are intended to be of relevance to primary care and specialist physicians with an emphasis on rational deployment of diagnostic tests, expedited implementation of long- and short-term medical therapy, timely consideration of revascularization, and practical follow-up measures.  相似文献   
995.
996.
997.
As the COVID-19 pandemic has spread across the globe, questions have arisen about the approach healthcare systems should adopt in order to optimally manage patient influx. With a focus on the impact of COVID-19 on the NHS, we describe the frontline experience of a severely affected hospital in close proximity to London. We highlight a protocol-driven approach, incorporating the use of CT in the rapid triage, assessment and cohorting of patients, in an environment where there was a lack of readily available, onsite RT-PCR testing facilities. Furthermore, the effects of the protocol on the effective streamlining of patient flow within the hospital are discussed, as are the resultant improvements in clinical management decisions within the acute care service. This model may help other healthcare systems in managing this pandemic whilst assessing their own needs and resources.  相似文献   
998.

Background

The T594M variant of the β-subunit of the sodium epithelial channel (ENaC) gene may contribute to hypertension in individuals of Indo-Aryan origin.

Methods

Present study was performed to assess the role of the ENaC gene variant as an independent risk factor for hypertension in subjects of Indo-Aryan ancestry. A total of 150 patients of recently detected essential hypertension and 150 matched controls were genotyped for the T594M polymorphism of the ENaC gene by PCR–RFLP method.

Results

β-T594M mutation was found to be non-polymorphic. There was major genotype call in both the groups i.e. cases and controls. Other phenotypic parameters like age, sex and body mass index were also similar among hypertensive patients and controls (P > 0.05). Hypertensive patients had significantly higher total cholesterol and triglycerides compared with controls (P < 0.0001).

Conclusion

These results do not suggest an important role for the T594M variant of the ENaC gene contributing to either the development or severity of hypertension in subjects of Indo-Aryan ancestry.  相似文献   
999.
1000.
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