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   1179篇
  免费   78篇
  国内免费   16篇
耳鼻咽喉   4篇
儿科学   69篇
妇产科学   35篇
基础医学   134篇
口腔科学   12篇
临床医学   107篇
内科学   254篇
皮肤病学   17篇
神经病学   41篇
特种医学   152篇
外科学   81篇
综合类   117篇
预防医学   89篇
眼科学   4篇
药学   53篇
中国医学   1篇
肿瘤学   103篇
  2022年   7篇
  2021年   10篇
  2019年   7篇
  2018年   8篇
  2017年   14篇
  2016年   19篇
  2015年   27篇
  2014年   35篇
  2013年   43篇
  2012年   53篇
  2011年   39篇
  2010年   55篇
  2009年   46篇
  2008年   66篇
  2007年   61篇
  2006年   43篇
  2005年   32篇
  2004年   32篇
  2003年   29篇
  2002年   31篇
  2001年   35篇
  2000年   27篇
  1999年   42篇
  1998年   50篇
  1997年   41篇
  1996年   34篇
  1995年   25篇
  1994年   31篇
  1993年   24篇
  1992年   19篇
  1991年   12篇
  1990年   25篇
  1989年   20篇
  1988年   27篇
  1987年   31篇
  1986年   19篇
  1985年   20篇
  1984年   7篇
  1983年   11篇
  1982年   17篇
  1981年   8篇
  1980年   6篇
  1979年   11篇
  1978年   12篇
  1977年   6篇
  1976年   8篇
  1975年   8篇
  1974年   8篇
  1973年   7篇
  1972年   5篇
排序方式: 共有1273条查询结果,搜索用时 15 毫秒
51.

Introduction

The optimal treatment of high energy tibial fractures remains controversial and a challenging orthopaedic problem. The role of external fixators for all these tibial fractures has been shown to be crucial.

Methods

A five-year consecutive series was reviewed retrospectively, identifying two treatment groups: Ilizarov and Taylor Spatial Frame (TSF; Smith & Nephew, Memphis, TN, US). Fracture healing time was the primary outcome measure.

Results

A total of 112 patients (85 Ilizarov, 37 TSF) were identified for the review with a mean age of 45 years. This was higher in women (57 years) than in men (41 years). There was no significant difference between frame types (p=0.83). The median healing time was 163 days in both groups. There was no significant difference in healing time between smokers and non-smokers (180 vs 165 days respectively, p=0.07), open or closed fractures (p=0.13) or age and healing time (Spearman''s r=0.12, p=0.18). There was no incidence of non-union or re-fracture following frame removal in either group.

Conclusions

Despite the assumption of the rigid construct of the TSF, the median time to union was similar to that of the Ilizarov frame and the TSF therefore can play a significant role in complex tibial fractures.  相似文献   
52.
BACKGROUND: In laboratory research, nicotine administration is associated with increases in blood pressure. In epidemiologic research, however, the amount of reported cigarette smoking has no consistent relation with blood pressure. The objective of this study was to examine the relation of a nicotine metabolite (salivary cotinine) to systolic and diastolic blood pressure in current smokers being screened for entry to a clinical trial. METHODS AND RESULTS: Data were obtained from 5164 middle-aged cigarette smokers during screening for the Lung Health Study. Multiple linear regression was used to examine the association of salivary cotinine and number of cigarettes smoked per day to systolic and diastolic blood pressure with age, body mass, years of education, alcohol intake, and recent caffeinated beverage use controlled in all analyses. Although smoking frequency was unrelated to blood pressure, salivary cotinine was related to greater systolic blood pressure in both men and women and greater diastolic blood pressure in men. CONCLUSIONS: The association between salivary cotinine and blood pressure in these analyses suggests that long-term nicotine exposure may be related to modest elevations in blood pressure in cigarette smokers.  相似文献   
53.
54.
55.
The purpose of this study was to analyze the expression of B cell growth factor (BCGF) receptors and to elucidate the biologic effects of biochemically purified natural BCGF at the B cell precursor stage of human B lineage lymphoid differentiation. The specific binding of radioiodinated high-mol-wt BCGF (125I-HMW-BCGF) and low-molecular-wt BCGF (125I-LMW-BCGF) to fresh marrow blasts from B cell precursor acute lymphoblastic leukemia (ALL) patients was initially investigated. The estimated number of radioiodinated BCGF molecules bound per blast ranged from undetectable to 24.3 X 10(3) for HMW-BCGF, and from 11.5 X 10(3) to 457.8 X 10(3) for LMW-BCGF. In 3H-TdR incorporation assays, 75% of cases showed a significant response to LMW-BCGF with a median stimulation index of 9.3. By comparison, only 33% of cases showed a significant response to HMW-BCGF with a median stimulation index of 2.4. Subsequently, B cell precursor colony assays were performed to assess and compare the biologic effects of BCGF on leukemic B lineage lymphoid progenitor cells. Among 28 cases studied, 57% responded to both HMW-BCGF and LMW-BCGF, 21% responded only to LMW-BCGF, and the remaining cases showed no proliferative response to either growth factor. The response patterns of virtually pure populations of FACS- sorted leukemic B cell precursors were essentially identical to the proliferative responses of unsorted leukemic B-cell precursors. Synergistic effects between HMW-BCGF and LMW-BCGF were observed in 80% of the cases that responded to both. The numbers of cell-bound radioiodinated BCGF molecules, the stimulation indices, as well as the number of B cell precursor colonies in BCGF-stimulated cultures showed a marked interpatient variation. Patients with structural chromosomal abnormalities (SCAs) involving 12p11-13 or patients with a Philadelphia chromosome showed a greater HMW-BCGF response at the level of leukemic progenitor cells than did other patients (P = .02). The LMW-BCGF response was significantly greater for patients with SCA than for patients without SCA (P = .04). The response of leukemic progenitor cells to HMW-BCGF or LMW-BCGF did not correlate with sex, age, disease status, FAB morphology, WBC at diagnosis, or immunophenotype. To our knowledge, this study represents the first detailed analyses of BCGF receptor expression and BCGF effects in B cell precursor ALL. The data presented provide direct evidence for the expression of functional receptors for both HMW-BCGF and LMW-BCGF in B cell precursor ALL.  相似文献   
56.
i(12p)-negative testicular germ cell tumors. A different group?   总被引:2,自引:0,他引:2  
Cytogenetic analysis was performed of three seminomas, two primary nonseminomas, and two mature residual teratomas following chemotherapy, all lacking i(12p). Testicular germ cell tumors without an i(12p) may represent a subgroup of germ cell tumors, also in their clinical course, compared with those having i(12p).  相似文献   
57.
58.
59.
We investigated the impact of pre-existing mental ill health on postpartum maternal outcomes. Women reporting childbirth trauma received counselling (Promoting Resilience in Mothers' Emotions; n?=?137) or parenting support (n?=?125) at birth and 6 weeks. The EuroQol Five dimensional (EQ-5D)-measured health-related quality of life at 6 weeks, 6 and 12 months. At 12 months, EQ-5D was better for women without mental health problems receiving PRIME (mean difference (MD) 0.06; 95 % confidence interval (CI) 0.02 to 0.10) or parenting support (MD 0.08; 95 % CI 0.01 to 0.14). Pre-existing mental health conditions influence quality of life in women with childbirth trauma.  相似文献   
60.
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