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   3727篇
  免费   250篇
  国内免费   25篇
耳鼻咽喉   39篇
儿科学   72篇
妇产科学   105篇
基础医学   500篇
口腔科学   204篇
临床医学   296篇
内科学   922篇
皮肤病学   122篇
神经病学   209篇
特种医学   81篇
外科学   576篇
综合类   35篇
一般理论   1篇
预防医学   288篇
眼科学   62篇
药学   222篇
中国医学   16篇
肿瘤学   252篇
  2023年   26篇
  2022年   66篇
  2021年   125篇
  2020年   73篇
  2019年   103篇
  2018年   112篇
  2017年   102篇
  2016年   70篇
  2015年   99篇
  2014年   162篇
  2013年   152篇
  2012年   284篇
  2011年   299篇
  2010年   164篇
  2009年   151篇
  2008年   272篇
  2007年   257篇
  2006年   228篇
  2005年   206篇
  2004年   219篇
  2003年   164篇
  2002年   167篇
  2001年   53篇
  2000年   48篇
  1999年   39篇
  1998年   20篇
  1997年   31篇
  1996年   23篇
  1995年   20篇
  1994年   15篇
  1993年   11篇
  1992年   21篇
  1991年   22篇
  1990年   20篇
  1989年   18篇
  1988年   13篇
  1987年   10篇
  1986年   17篇
  1985年   11篇
  1984年   16篇
  1983年   13篇
  1982年   6篇
  1981年   5篇
  1980年   5篇
  1979年   11篇
  1978年   6篇
  1976年   10篇
  1973年   5篇
  1972年   7篇
  1970年   4篇
排序方式: 共有4002条查询结果,搜索用时 46 毫秒
1.
We report on a 3‐year‐old girl with a microvesicular generalized rash in whom primary infection by parvovirus B19 was demonstrated by seroconversion. To our knowledge, this is the first instance of an eruption arising from parvovirus B19 with this peculiar clinical pattern.  相似文献   
2.
Clinical decisions are often made with incomplete information, yet patient care decisions are made every day. Patients vary clinically, uncertainty exists in diagnostic and prognostic information, and many preventive and treatment alternatives have not been formally assessed for their effectiveness. Because scientific information will never answer all clinical questions, clinical decisions are partially based on probabilistic information.
This paper describes how to apply clinical decision making to diagnosing and managing dental caries and periodontal diseases. By using explicit information to quantify probabilities and outcomes, clinical decision making analyzes decisions made under uncertain conditions and the uncertain impact of clinical information.
Clinical decision making incorporates concepts for preventing, diagnosing and treating dental caries and periodontal diseases: risk assessment, evidence-based dentistry, and multiple oral health outcomes. This information can serve as a tool for clinicians to augment clinical judgment and expertise.  相似文献   
3.
Although renal dysfunction is common after liver transplantation, postoperative renal function after split liver transplantation (SLT) has not been well studied. Renal function immediately after surgery was analyzed retrospectively in 16 patients that received a SLT (SLT group). The results were compared with corresponding data from 31 matched patients that received a full-size liver transplant (FSLT group) during the same period. Serum creatinine (SCr) was measured before surgery, and, after transplantation, daily during the first week and at days 14, 21, and 28. Renal dysfunction (RD) was defined as the requirement for renal replacement therapy (RRT) or a 100% increase in SCr if the basal value had been <1.0 mg/dL or a 50% increase in SCr if the basal value had been >1.0 mg/dL. SCr had to be at least 1.5 mg/dL for a diagnosis of RD to be considered. The classification of RD was: mild, SCr 1.5-2.4 mg/dL; moderate, SCr 2.5-4.0 mg/dL; or severe, SCr >4.0 mg/dL (the requirement for RRT). Both donor and recipient age and cold ischemia time were lower in the SLT group than in the FSLT group (P < 0.05). Length of surgery was longer in the SLT group (P < 0.05). There were no significant differences between groups with respect to Model for End-Stage Liver Disease scores, the need for transfusions, the length of admission to the intensive care unit (ICU), survival rate, individual severity index, or sepsis-related organ failure assessment scores at the time of diagnosing RD. Immunosuppression regimens were similar in both groups. RD developed in 82% of SLT patients, but in only 58% of FSLT patients (P = not significant [NS]). Among SLT patients, RD (23.0% mild, 15.5% moderate, and 61.5% severe) was more severe (P = 0.007) than in FSLT patients (63.1% mild, 15.8% moderate, and 24.1% severe). The requirement for RRT in the SLT group (43.7%) was significantly greater (P < 0.05) than that in the FSLT group (12.9%). This finding may be due to the different incidence of sepsis in the 2 groups (SLT 37.5% vs. FSLT 9.7%; P < 0.05). In conclusion, although the number of patients studied was small, our data suggest a higher incidence of RD and a greater requirement for RRT in patients that receive a split liver graft than in those that receive a full size liver graft.  相似文献   
4.
5.
6.
7.
8.
Mice pretreated with Bacillus megaterium ATCC 33085 grown on TSA medium developed a significant increase in primary antibody response to SRBC. Conversely, pretreatment with a spore suspension harvested from nutrient Agar medium decreased this antibody response. A suspension of organisms grown on a defined, phosphorus-deficient medium (P-Medium) had no effect. Otherwise, only the spore suspension was able to enhance the contact sensitivity to dinitrofluorobenzene. Peritoneal leucocyte numbers were increased by inoculation with both TSA-cultured bacteria and the spore suspension, but not by P-Medium-cultured bacteria. Administration of both the spore suspension and P-Medium-cultured bacteria decreased the in vitro phagocytosis by peritoneal adherent cells. These immunomodulator properties are discussed in relation to characteristics of the strain tested.  相似文献   
9.
Since their approval in 1998, the popularity of selective cyclooxygenase-2 (COX2) inhibitors has swung from a domination of drug sales to serious disputes about their cardiovascular safety. Despite the numerous studies on COX2 inhibitors that have emerged, drawing conclusions about their cardiovascular safety has been complicated by conflicting results, underpowered clinical trials, and the lack of a placebo group and use of post hoc analyses in many trials. Nonetheless, certain conclusions can be made with reasonable accuracy. This review addresses the controversy in 3 segments. It begins with a discussion of the several mechanisms proposed to explain how selective COX2 inhibition impacts the cardiovascular system. This is followed by a recount of the several clinical studies that delved into the cardiovascular outcomes associated with COX2 inhibitors. Finally, answers to key questions are provided to assist the clinician in devising a systematic approach to the risk-benefit analysis of COX2 inhibitors in actual practice.  相似文献   
10.
PURPOSE: The goal of this study was to analyze the effect of positive end-expiratory pressure (PEEP), with and without a lung recruitment maneuver, on dead space. METHODS: 16 anesthetized patients were sequentially studied in three steps: 1) without PEEP (ZEEP), 2) with 5 cm H(2)O of PEEP and 3) with 5 cm H(2)O of PEEP after an alveolar recruitment strategy (ARS). Ventilation was maintained constant. The single breath test of CO(2) (SBT-CO(2)), arterial oxygenation, end-expiratory lung volume (EELV) and respiratory compliance were recorded every 30 min. RESULTS: Physiological dead space to tidal volume decreased after ARS (0.45 +/- 0.01) compared with ZEEP (0.50 +/- 0.07, P < 0.05) and PEEP (0.51 +/- 0.06, P < 0.05). The elimination of CO(2) per breath increased during PEEP (25 +/- 3.3 mL.min(-1)) and ARS (27 +/- 3.2 mL.min(-1)) compared to ZEEP (23 +/- 2.6 mL.min(-1), P < 0.05), although ARS showed larger values than PEEP (P < 0.05). Pa-etCO(2) difference was lower after recruitment (0.9 +/- 0.5 kPa, P < 0.05) compared to ZEEP (1.1 +/- 0.5 kPa) and PEEP (1.2 +/- 0.5 kPa). Slope II increased after ARS (63 +/- 11%/L, P < 0.05) compared with ZEEP (46 +/- 7.7%/L) and PEEP (56 +/- 10%/L). Slope III decreased significantly after recruitment (0.13 +/- 0.07 1/L) compared with ZEEP (0.21 +/- 0.11 1/L) and PEEP (0.18 +/- 0.10 1/L). The angle between slope II and III decreased only after ARS. After lung recruitment, PaO(2), EELV, and compliance increased significantly compared with ZEEP and PEEP. CONCLUSION: Lung recruitment improved the efficiency of ventilation in anesthetized patients.  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