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   6202篇
  免费   422篇
  国内免费   11篇
耳鼻咽喉   93篇
儿科学   176篇
妇产科学   143篇
基础医学   787篇
口腔科学   62篇
临床医学   739篇
内科学   1205篇
皮肤病学   71篇
神经病学   609篇
特种医学   127篇
外科学   788篇
综合类   38篇
一般理论   14篇
预防医学   707篇
眼科学   158篇
药学   504篇
中国医学   4篇
肿瘤学   410篇
  2024年   9篇
  2023年   72篇
  2022年   117篇
  2021年   291篇
  2020年   153篇
  2019年   227篇
  2018年   236篇
  2017年   191篇
  2016年   199篇
  2015年   233篇
  2014年   298篇
  2013年   438篇
  2012年   600篇
  2011年   555篇
  2010年   260篇
  2009年   257篇
  2008年   422篇
  2007年   420篇
  2006年   368篇
  2005年   372篇
  2004年   276篇
  2003年   200篇
  2002年   201篇
  2001年   29篇
  2000年   15篇
  1999年   17篇
  1998年   33篇
  1997年   14篇
  1996年   15篇
  1995年   12篇
  1994年   10篇
  1993年   17篇
  1992年   17篇
  1991年   8篇
  1990年   9篇
  1989年   7篇
  1988年   7篇
  1987年   5篇
  1986年   4篇
  1985年   5篇
  1984年   7篇
  1983年   1篇
  1982年   2篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1976年   1篇
  1973年   1篇
排序方式: 共有6635条查询结果,搜索用时 11 毫秒
51.
52.
New treatment strategies are urgently needed to overcome early mortality in acute bacterial infections. Previous studies have shown that administration of a novel immunoactivating peptide (P4) alongside passive immunotherapy prevents the onset of septicemia and rescues mice from lethal invasive disease models of pneumococcal pneumonia and sepsis. In this study, using two diverse populations of adult volunteers, we determined whether P4 treatment of human alveolar macrophages would upregulate phagocytic killing of Streptococcus pneumoniaeex vivo. We also measured macrophage intracellular oxidation, cytokine secretion, and surface marker expression following stimulation. Peptide treatment showed enhanced bacterial killing in the absence of nonspecific inflammation, consistent with therapeutic potential. This is the first demonstration of P4 efficacy on ex vivo-derived human lung cells.  相似文献   
53.
Purpose : To collect qualitative information about personal experiences with stroke rehabilitation from members of a community based stroke club. Method : In this focused ethnographic study, four data collectors observed and videotaped two sessions of a community based stroke club. The videotape and written notes were reviewed and analysed according to standard qualitative research procedures. Results : Two themes emerged from analysis of the qualitative data: concerns that individualized needs were not addressed during the rehabilitation process and that services were insufficient to ease the transition to community living. Conclusions : Rehabilitation professionals can benefit from soliciting reflections and suggestions from individuals who have returned to community living after completing poststroke rehabilitation programmes. Specific recommendations are provided for tailoring interventions to meet individual goals, for enhancing follow up services provided after inpatient rehabilitation, and for providing early access to available resources in stroke survivors' communities.  相似文献   
54.
Background and purpose: The transition from a baccalaureate program to a medical curriculum can be a difficult period for some students. Our study asked whether providing students with review materials and a means of assessing their degree of preparedness prior to matriculation influenced actual and perceived performance in 1st-year basic science courses. Methods: Didactic review materials in basic science subjects encountered in the 1st year were made available to prematriculants online. Access to materials for each subject was contingent upon completion of a pretest. Prematriculants were free to use the materials as they saw fit. Once students matriculated, performance in basic science subjects was compared between those who had accessed the materials and those who had not. Students who accessed the materials were also surveyed to determine if they perceived any benefit from their use. Results: More than half of matriculants chose to access the intervention materials. There was no significant difference in MCAT, prerequisite grade point average, or total grade point average between those students who chose to access the intervention materials and those who did not. Students who accessed the intervention materials reported gains in confidence in their ability to perform well in medical school. Those students who accessed the intervention materials had significantly higher examination scores in an early basic science course than those who did not. Conclusions: An online prematriculation intervention can provide useful background material to interested students. Access to this material increased performance in a 1st-year basic science course and was perceived as valuable by students.  相似文献   
55.
56.
This case study reports on DNA analysis from different skeletal elements of an individual recovered 2 years after going missing in the English Channel. Selected bones were also re-submerged for an additional 2 years and re-analysed. By comparing results from both time points, this study concludes that high-load-bearing bones, particularly the bones of the feet, appear to be a preferable source of DNA for identification of skeletal tissue recovered from similar conditions.  相似文献   
57.
The goal of animal wound healing models is to replicate human physiology and predict therapeutic outcomes. There is currently no model of wound healing in rodents that closely parallels human wound healing. Rodents are attractive candidates for wound healing studies because of their availability, low cost, and ease of handling. However, rodent models have been criticized because the major mechanism of wound closure is contraction, whereas in humans reepithelialization and granulation tissue formation are the major mechanisms involved. This article describes a novel model of wound healing in mice utilizing wound splinting that is accurate, reproducible, minimizes wound contraction, and allows wound healing to occur through the processes of granulation and reepithelialization. Our results show that splinted wounds have an increased amount of granulation tissue deposition as compared to controls, but the rate of reepithelialization is not affected. Thus, this model eliminates wound contraction and allows rodents' wounds to heal by epithelialization and granulation tissue formation. Given these analogies to human wound healing, we believe that this technique is a useful model for the study of wound healing mechanisms and for the evaluation of new therapeutic modalities.  相似文献   
58.
A subset of corticotropin‐releasing hormone (CRH) neurons was previously identified in the hippocampus with unknown function. Here we demonstrate that hippocampal CRH neurons represent a novel subtype of interneurons in the hippocampus, exhibiting unique morphology, electrophysiological properties, molecular markers, and connectivity. This subset of hippocampal CRH neurons in the mouse reside in the CA1 pyramidal cell layer and tract tracing studies using AAV‐Flex‐ChR2‐tdTomato reveal dense back‐projections of these neurons onto principal neurons in the CA3 region of the hippocampus. These hippocampal CRH neurons express both GABA and GAD67 and using in vitro optogenetic techniques, we demonstrate that these neurons make functional connections and release GABA onto CA3 principal neurons. The location, morphology, and importantly the functional connectivity of these neurons demonstrate that hippocampal CRH neurons represent a unique subtype of hippocampal interneurons. The connectivity of these neurons has significant implications for hippocampal function. © 2015 Wiley Periodicals, Inc.  相似文献   
59.

Background

Although recent studies have shown the feasibility and safety of robotic adrenalectomy, an advantage over the laparoscopic approach has not been demonstrated. Our hypothesis was that the use of the robot would facilitate minimally invasive resection of large adrenal tumors.

Methods

Adrenal tumors ??5?cm resected robotically were compared with those removed laparoscopically from a prospective institutional review board-approved adrenal database. Clinical and perioperative parameters were analyzed using t and chi-square tests. All data are expressed as mean?±?standard error of mean.

Results

There were 24 patients with 25 tumors in the robotic group and 38 patients with 38 tumors in the laparoscopic group. Tumor size was similar in both groups (6.5?±?0.4 [robotic] vs 6.2?±?0.3?cm [laparoscopic], P?=?.661). Operative time was shorter for the robotic versus laparoscopic group (159.4?±?13.4 vs 187.2?±?8.3 min, respectively, P?=?.043), while estimated blood loss was similar (P?=?.147). The conversion to open rate was less in the robotic (4%) versus the laparoscopic (11%) group; P?=?.043. Hospital stay was shorter for the robotic group (1.4?±?0.2 vs 1.9?±?0.1?days, respectively, P?=?.009). The 30-day morbidity was 0 in robotic and 2.7% in laparoscopic group. Pathology was similar between groups.

Conclusions

Our study shows that the use of the robot could shorten operative time and decrease the rate of conversion to open for adrenal tumors larger than 5?cm. Based on our favorable experience, robotic adrenalectomy has become our preferred minimally invasive surgical approach for removing large adrenal tumors.  相似文献   
60.
There have been few studies examining the short-term effect of high-impact activities on bone metabolism measured by bone serum marker concentrations. The purpose of this study was to examine the effect of short-term high-impact jump activity on bone turnover in female college-aged non-athletes. Twenty six healthy females were randomly assigned to a control or jump group. The subjects jumped 5 days per week for 2 weeks. The participants completed 10 jumps per session. A general health questionnaire and a bone-specific physical activity assessment instrument (BPAQ) were completed. BPAQ scores were calculated based on the past history of exercise. Blood draws were taken in both groups before and after the two-week experimental period. The vertical ground reaction force (VGRF) of all jumps and jump height were measured for each subject daily and the osteogenic index (OI) was measured. Concentrations of serum osteocalcin (OC), Bone Specific Alkaline Phosphatase (BAP), C-Terminal Telopeptides of Type I Collagen (CTX) and plasma Tartrate-Resistant Acid Phosphatase (TRAP5b) were assessed pre and post jump protocol to measure bone formation and resoprtion respectively. A significant interaction (time x group) was found in TRAP5b, and BAP values (p < 0.05). There was a significant decrease in CTX and BAP values in the jump group (p < 0.05) after the two week jump protocol. No significant interactions or changes were observed in OC values for either the jump or the control group. Two weeks of jump activity consisting of 10 jumps/day for 5 days/week with a weekly osteogenic index of 52.6 significantly decreased markers of bone resorption (TRAP5b and CTX) and bone formation (BAP) in young female non-athletes.

Key points

  • Please provide 3-5 bullet points of the study.
  • Inductive qualitative methodologies can encourage the much-needed voice of female youth in sport and physical activity research.
  • Vignettes serve, not only as a method to illustrate data, but also as a medium to teach contextually relevant information to participants and sport science service providers.
  • The barriers and solutions to female youth engagement in physical activity are best understood through the perspectives of the intended participant.
  • Female youth can serve as central informants in the development and analysis of research projects relating to female youth physical activity.
Key words: Jump exercise, vertical ground reaction force, bone serum markers, randomized controlled study  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