首页 | 官方网站   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   6403篇
  免费   411篇
  国内免费   56篇
医药卫生   6870篇
  2023年   101篇
  2022年   50篇
  2021年   336篇
  2020年   172篇
  2019年   189篇
  2018年   219篇
  2017年   171篇
  2016年   212篇
  2015年   200篇
  2014年   217篇
  2013年   281篇
  2012年   430篇
  2011年   488篇
  2010年   244篇
  2009年   178篇
  2008年   299篇
  2007年   310篇
  2006年   284篇
  2005年   258篇
  2004年   230篇
  2003年   240篇
  2002年   217篇
  2001年   73篇
  2000年   88篇
  1999年   107篇
  1998年   43篇
  1997年   45篇
  1996年   44篇
  1995年   37篇
  1994年   39篇
  1993年   28篇
  1992年   70篇
  1991年   75篇
  1990年   68篇
  1989年   76篇
  1988年   61篇
  1987年   66篇
  1986年   60篇
  1985年   63篇
  1984年   55篇
  1983年   41篇
  1982年   34篇
  1979年   33篇
  1978年   28篇
  1976年   30篇
  1975年   29篇
  1974年   30篇
  1972年   24篇
  1971年   23篇
  1968年   23篇
排序方式: 共有6870条查询结果,搜索用时 15 毫秒
1.
Pediatric Surgery International - The programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway has garnered much attention for its roles in clinical oncology. The aim of this study was...  相似文献   
2.
Objectives: To examine the factors associated with increase in lumbar spine bone mineral density (LS-BMD) by bisphosphonates (BPs) with active vitamin D analog (aVD).

Methods: Two independent postmenopausal osteoporotic patients treated by BPs with aVD for 24 months (Study 1: n?=?93, Study 2: n?=?99) were retrospectively analyzed.

Results: In Study 1, LS-BMD of the patients significantly increased for 24 m (5.4%, p?r2: 0.088, p?=?.02). While average sCa of the patients was 9.2?mg/dL before treatment, it increased time-dependently to 9.6?mg/dL for 24 m by treatment. As each patient had their LS-BMD five times during the study, there were four instances of %LS-BMD in each patient, resulting in 372 instances of %LS-BMD in Study 1. The smallest Akaike’s information criterion value for the most appropriate cut-off levels of sCa for %LS-BMD by treatment every 6 m was 9.3?mg/dL. The %LS-BMD by treatment for 6 m during 24 m period in patients with sCa ≥9.3?mg/dL (1.5%) was significantly higher than that in patients with sCa <9.3?mg/dL (0.8%, p?=?.038). The results of Study 2 were similar to those of Study 1, confirming the phenomena observed.

Conclusion: sCa was associated with an increased LS-BMD by BPs with aVD.  相似文献   
3.
ObjectiveTo verify if the relationship between pain catastrophizing and pain worsening would be mediated by muscle weakness and disability in patients with symptomatic knee osteoarthritis.MethodsThis was a cross-sectional study in a hospital out-patient setting. Convenience sampling was used with a total of 50 participants with symptomatic knee osteoarthritis. Pain and the activities of daily livings (ADL) were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale. Pain catastrophizing was assessed using the Coping Strategy Questionnaire (CSQ) subscale. Muscle strength of knee extension and 30-s chair stand test (30CST) were also assessed. Path analysis was performed to test the hypothetical model. Goodness of fit of models were assessed by using statistical parameters such as the chi-square value, goodness of fit index (GFI), adjusted goodness of fit index (AGFI), comparative fit index (CFI), and root mean square error of approximation (RMSEA).ResultsThe chi-square values were not significant (chi-square = 0.283, p = 0.594), and the indices of goodness of fit were high, implying a valid model (GFI = 1.000; AGFI = 0.997; CFI = 1.000; RMSEA = 0.000). Pain was influenced significantly by muscle strength and ADL; muscle strength was influenced significantly by ADL via 30CST; ADL was influenced by pain catastrophizing.ConclusionThe relationship between pain catastrophizing with pain worsening are mediated by muscle weakness and disability.  相似文献   
4.
5.
This study focuses on obtaining more information about the site of anastomosis, with three-dimensional examination using methylmethacrylate resin (Mercox) corrosion casts. Seventy microvascular anastomoses were performed in Wistar albino rats, divided into two groups before sacrifice. In Group 1 (35), Mercox was injected into the vessels, whereas in Group 2 (35), the tissues were prepared without injecting Mercox. Both groups were compared under the scanning electron microscope (SEM). The SEM preparation in Group 1 was simple, easy, and artifacts were significantly minimized. The anastomotic site could be well appreciated in three-dimensional views. Clear negative imprints of the endothelial surface were achieved without any breakage in the Mercox corrosion cast, and it can be reliably used in the evaluation of small vessel anastomosis.  相似文献   
6.
Two cases of vasovagal syncope (VVS) during venous access are reported. Both patients had a history of fainting episodes and experienced bradycardia with asystole, hypotension, and fainting. Pain and phobic stress during venous access triggered an increase in parasympathetic tone, resulting in bradycardia with asystole and hypotension in both cases. Hypotension and bradycardia likely caused cerebral hypoperfusion, leading to fainting. The intense parasympathetic tone triggered by somatic or emotional stress was likely responsible for directly depressing the sinus node, leading to asystole and bradycardia. Bradycardia with asystole progressing to syncope is a potentially fatal dysrhythmia in patients with cardiovascular disease or older patients with decreased cardiac function. Appropriate treatment for VVS includes the administration of intravenous fluids, vagolytics, ephedrine, and the rapid use of the Trendelenburg position. Intravenous fluids and atropine were used to treat the present patients.  相似文献   
7.
Left ventricular (LV) remodeling after myocardial infarction (MI) is a maladaptive process that increases the risk of heart failure and death. The myocardial phosphoinositide cycle, which is located downstream from several neurohumoral factors, plays a crucial role in LV remodeling. Our animal studies demonstrated that 1-[1-11C]butyryl-2-palmitoyl-rac-glycerol (11C-DAG) can be used to visualize regions with an activated phosphoinositide cycle. Therefore, we examined whether myocardial 11C-DAG accumulation assessed by PET is relevant to LV enlargement and systolic dysfunction in post-MI patients. METHODS: We performed PET with 11C-DAG in 13 post-anteroseptal MI patients and 4 healthy volunteers. We placed regions of interest on the noninfarcted myocardium and calculated the myocardium-to-left atrial (LA) chamber ratio of 11C-DAG accumulation. RESULTS: The myocardium-to-LA chamber ratio of 11C-DAG was significantly higher in the post-MI patients (mean +/- SD, 1.73 +/- 0.35) compared with that of the healthy volunteers (mean +/- SD, 1.25 +/- 0.13; P < 0.05). In the post-MI patients, the myocardium-to-LA chamber ratio of (11)C-DAG was significantly correlated with the LV end-diastolic volume index (r = 0.79, P < 0.01) and the plasma concentration of brain natriuretic peptide (r = 0.85, P < 0.001) and negatively correlated with the LV ejection fraction (r = -0.69, P < 0.01). CONCLUSION: These findings suggest that the myocardial 11C-DAG accumulation assessed by PET is relevant to LV enlargement, LV systolic dysfunction, and humoral activation in post-MI patients. This new imaging strategy based on intracellular signaling may contribute to the assessment and treatment of post-MI patients.  相似文献   
8.
Background: The study hypothesizes that nitrous oxide (N2O) releases opioid peptide in the brain stem, which results in inhibition of [gamma]-aminobutyric acid-mediated (GABAergic) neurons that tonically inhibit the descending noradrenergic inhibitory neurons (DNIN), resulting in activation of DNIN. In the spinal cord, activation of DNIN leads to the release of norepinephrine, which inhibits nociceptive processing through direct activation of [alpha]2 adrenoceptor and indirect activation of GABAergic neurons through [alpha]1 adrenoceptor. Arising from this hypothesis, it follows that GABAergic neurons will modulate the antinociceptive effect of N2O in diametrically opposite directions at supraspinal and spinal levels. The authors have tested this tenet and further examined the effect of midazolam, a GABA-mimetic agent, on N2O-induced antinociceptive effect.

Methods: Adult male Fischer rats were administered muscimol (GABAA receptor agonist) intracerebroventricularly (icv), gabazine (GABAA receptor antagonist) intrathecally (intrathecal), or midazolam intraperitoneally (intraperitoneal). Fifteen minutes later, they were exposed to air or 75% N2O and were subjected to the plantar test after 30 min of gas exposure. In some animals administered with midazolam, gas exposure was continued for 90 min, and the brain and spinal cord were examined immunohistochemically.

Results: The N2O-induced antinociceptive effect, which was attenuated by icv muscimol, intrathecal gabazine, and intraperitoneal midazolam. Midazolam inhibited N2O-induced c-Fos expression (a marker of neuronal activation) in the pontine A7 and spinal cord.  相似文献   

9.
10.
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-23

京公网安备 11010802026262号