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   3000篇
  免费   247篇
  国内免费   39篇
耳鼻咽喉   16篇
儿科学   72篇
妇产科学   48篇
基础医学   371篇
口腔科学   51篇
临床医学   348篇
内科学   738篇
皮肤病学   53篇
神经病学   210篇
特种医学   139篇
外科学   400篇
综合类   119篇
预防医学   186篇
眼科学   64篇
药学   181篇
中国医学   8篇
肿瘤学   282篇
  2023年   18篇
  2022年   26篇
  2021年   67篇
  2020年   45篇
  2019年   64篇
  2018年   59篇
  2017年   46篇
  2016年   61篇
  2015年   78篇
  2014年   103篇
  2013年   148篇
  2012年   165篇
  2011年   185篇
  2010年   119篇
  2009年   118篇
  2008年   157篇
  2007年   181篇
  2006年   157篇
  2005年   153篇
  2004年   141篇
  2003年   115篇
  2002年   119篇
  2001年   85篇
  2000年   53篇
  1999年   57篇
  1998年   67篇
  1997年   65篇
  1996年   42篇
  1995年   36篇
  1994年   37篇
  1993年   39篇
  1992年   23篇
  1991年   22篇
  1990年   33篇
  1989年   53篇
  1988年   31篇
  1987年   39篇
  1986年   28篇
  1985年   13篇
  1984年   17篇
  1983年   14篇
  1982年   14篇
  1981年   16篇
  1980年   14篇
  1977年   8篇
  1976年   16篇
  1975年   11篇
  1966年   6篇
  1963年   6篇
  1941年   11篇
排序方式: 共有3286条查询结果,搜索用时 31 毫秒
1.
2.
In the present review, we updated current information on the chemistry, contents, and anticancer properties of matrine (MT), oxymatrine (OMT), and compound Kushen injection (CKI). The anticancer properties were focused on lung, breast, and liver cancer cells because they are most susceptible. Sources of information were from Google, Google Scholar, PubMed, PubMed Central, Science Direct, PubChem, J-Stage, Directory of Open Access Journals (DOAJ), and China National Knowledge Infrastructure (CNKI). Reference was also made on botanical websites, such as Flora of China and World Flora Online. MT and OMT are dominant quinolizidine alkaloids from the roots of Sophora flavescens (Kushen) of the family Fabaceae. Against lung, breast, and liver cancer cells, MT and OMT inhibit cell proliferation; induce cell cycle arrest, apoptosis, and autophagy; restrict angiogenesis; and inhibit cell metastasis, invasion, and migration. The processes involve various molecular targets and signaling pathways. CKI is a traditional Chinese medicine (TCM) composed of root extracts of S. flavescens and Smilax glabra (Baituling) of the family Smilacaceae. With MT and OMT as major components, CKI has been approved for the treatment of cancer in China more than 20 years ago. In recent years, systematic reviews and meta-analysis have been undertaken to evaluate the anticancer effects of CKI. When CKI is used alone and in combination with chemotherapy of western medicine, there is much to be learned concerning their interactions besides their individual and integrated efficacy. Some perspectives of MT, OMT, and CKI are discussed, and their suggestions for future research are provided.  相似文献   
3.
We report a case of successful transvenous, catheter-based, cavotricuspid isthmus ablation for treatment of atrial flutter using microwave energy. Microwave energy was delivered at 900–930 MHz using 21 W of power. Bidirectional cavotricuspid isthmus conduction block was achieved by microwave ablation without any patient discomfort or complication during the procedure. Our initial experience suggests that transcatheter microwave ablation is feasible for the cure of typical atrial flutter.  相似文献   
4.
OBJECTIVES: The study aimed to review the etiologies of patients who underwent surgery for small bowel obstruction (SBO) and to evaluate the risk factors affecting the early postoperative outcomes. MATERIALS AND METHODS: A case series of 430 patients (252 men) with a mean age of 64.5 years, who underwent 437 operations for SBO, were retrospectively reviewed. RESULTS: Peritoneal adhesions and hernia were the most common causes of SBO, contributing 42.3 and 26.8% of all cases, respectively. Strangulation occurred in 27.7% and caused nonviable bowel in 13.0% of obstructing episodes. Old age (age >/= 70 years), female patient, nonadhesive obstruction, and hernia were the independent significant factors associated with bowel strangulation. The 30-day mortality was 6.5%, and the median postoperative hospital stay was 8 days. Old age, the presence of premorbid pulmonary disease, and malignant obstruction were the independent factors associated with operative mortality. The overall complication rate was 35.5%, and old age was the only significant factor associated with postoperative complications. CONCLUSIONS: Surgery for SBO is still associated with significant mortality and morbidity. As old age is significantly associated with an increased incidence of strangulation, operative mortality, and complications, this group of patients should be managed with extra cautions to avoid unfavorable outcome of surgery.  相似文献   
5.
In today''s environment, providers are extremely time-constrained. Assembling relevant contextual data to make decisions on laboratory results can take a significant amount of time from the day. The Regenstrief Institute has created a system which leverages data within Indiana Health Information Exchange''s (IHIE''s) repository, the Indiana Network for Patient Care (INPC), to provide well-organized and contextual information on returning laboratory results to outpatient providers. The system described here uses data extracted from INPC to add historical test results, medication-dispensing events, visit information, and clinical reminders to traditional laboratory result reports. These “Enhanced Laboratory Reports” (ELRs) are seamlessly delivered to outpatient practices connected through IHIE via the DOCS4DOCS clinical messaging service. All practices, including those without electronic medical record systems, can receive ELRs. In this paper, the design and implementation issues in creating this system are discussed, and generally favorable preliminary results of attitudes by providers towards ELRs are reported.  相似文献   
6.
Three patients who presented with scrotal swelling within a few days of inguinal herniorrhaphy are reported. Ultrasonography scans performed in these patients all demonstrated features suspicious of recurrence of hernia. One patient underwent surgical exploration, which revealed only a scrotal haematoma without evidence of recurrent hernia. The other two patients were managed conservatively because clinically the swellings were regarded to be more compatible with haematoma. Both patients had subsequent resolution of the scrotal swelling with no clinical evidence of recurrence of hernia on follow‐up. It is concluded that sonographic diagnosis of recurrence of hernia shortly after inguinal herniorrhaphy can occasionally be misleading.  相似文献   
7.
As a part of our ongoing study on Alzheimer's disease (AD) in elderly African Americans, we obtained clinical assessment and apolipoprotein E (ApoE) genotype data on 288 individuals (including 60 with AD). The ApoE σ4 allele frequency was significantly increased in AD patients compared with controls. The age-adjusted odds ratio (OR) for AD in σ4 homozygotes was 4.83 (95% confidence interval [CI], 1.71–13.64) compared with the σ3/σ3 genotype, but the OR for AD with the σ3/σ4 genotype did not reach significance (1.20; 95% CI, 0.58–2.45). These findings suggest that the association between ApoE σ4 and AD is weaker in African Americans than in whites.  相似文献   
8.
Background. Extensive questioning of patients with a wide variety of skin disorders led to the impression that nocturnal overheating was probably an important factor in the initiation and the perpetuation of many skin disorders. Methods. In order to test the hypothesis, 12 “clean-skinned” subjects (6M/6F) aged 18 to 45 years were monitored electronically every 30 seconds during an 8 hour sleep period (2300 to 0700 hours), sleeping under a standard 10 tog duvet. Results. All the subjects were too hot by 3 to 4°C. All showed changes in their EEG patterns with reduced REM sleep, increased awakenings, and all showed changes in their sleep stage patterns. In addition, they all showed evidence of increased sweating in the “heat-sink” area. Conclusions. The mechanisms where by such changes could be implicated in the precipitation and perpetuation of skin disease are discussed. “Lifestyle” modification as a very effective, noninvasive, therapeutic regime is recommended. Further research along these lines would probably be very valuable and instructive.  相似文献   
9.
Background In recent years, the number of women entering the field of emergency medicine (EM) has increased.
Objectives To determine if authorship in EM publications has increased in parallel with this trend.
Methods The gender of first and last authors of EM articles in Academic Emergency Medicine , American Journal of Emergency Medicine , Annals of Emergency Medicine , and Journal of Emergency Medicine were examined. The authors reviewed articles from 1985, 1995, and 2005 for American Journal of Emergency Medicine , Annals of Emergency Medicine , and Journal of Emergency Medicine and from 1999 and 2005 for Academic Emergency Medicine . The primary outcomes were the proportions of female authors.
Results A total of 2,016 articles were reviewed. Overall, 18% of first and last authors were female. Respectively, for 1985, 1995, 1999, and 2005, the proportions of female first authors were 9%, 15%, 19%, and 24%; the proportions of female last authors were 9%, 18%, 19%, and 22%. The trend of increases in female authorship was statistically significant.
Conclusions Although female authorship remains a minority in EM publications, it has increased significantly in parallel with increases in female participation in EM.  相似文献   
10.
BACKGROUND: Increased autoantibody prevalence has been described in instances of high-dose exposure to polychlorinated biphenyls (PCBs). In 1996, an equipment malfunction at the Swan Hills Treatment Centre in Alberta, Canada, caused the release of gases containing PCBs into the ambient air. In view of the immune effects of PCBs and their potential as endocrine disruptors, we assessed autoantibody prevalence and looked for correlations with PCB levels. METHODS: Fifty-seven persons living within a 100 km radius of the waste treatment facility were assessed. Autoantibodies were measured by indirect immunofluorescence, double immunodiffusion, and immunoblotting. The levels of 26 congeners of PCBs were measured by gas chromatography and mass spectrometry. Provincial health records for physician visits and hospitalizations were reviewed for diagnoses of autoimmune disease. RESULTS: The prevalence of autoantibodies was 11% in the study participants and 0% in healthy controls. There was no correlation of PCB levels with autoantibody results. There was no associated increase in autoimmune disease noted on physician visits or hospitalizations. PCB levels were comparable to background levels reported for other populations. CONCLUSION: A correlation of titers of autoantibodies in the sera of individuals at risk and the blood levels of PCBs was not found, and the prevalence of autoantibodies in the at-risk group was not statistically different (p > .05) from that of an unexposed control group. The study group had higher titers of autoantibodies and some strong reactivity with intracellular antigens, but the significance of this observation may be understood only after long-term clinical assessments and follow-up.  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