全文获取类型
收费全文 | 36834篇 |
免费 | 3015篇 |
国内免费 | 102篇 |
专业分类
耳鼻咽喉 | 395篇 |
儿科学 | 1012篇 |
妇产科学 | 563篇 |
基础医学 | 4975篇 |
口腔科学 | 747篇 |
临床医学 | 3500篇 |
内科学 | 7654篇 |
皮肤病学 | 577篇 |
神经病学 | 4028篇 |
特种医学 | 1478篇 |
外国民族医学 | 3篇 |
外科学 | 5301篇 |
综合类 | 855篇 |
一般理论 | 73篇 |
预防医学 | 3257篇 |
眼科学 | 729篇 |
药学 | 2362篇 |
中国医学 | 21篇 |
肿瘤学 | 2421篇 |
出版年
2023年 | 130篇 |
2022年 | 219篇 |
2021年 | 541篇 |
2020年 | 294篇 |
2019年 | 527篇 |
2018年 | 648篇 |
2017年 | 487篇 |
2016年 | 548篇 |
2015年 | 643篇 |
2014年 | 952篇 |
2013年 | 1501篇 |
2012年 | 2230篇 |
2011年 | 2370篇 |
2010年 | 1269篇 |
2009年 | 1241篇 |
2008年 | 2236篇 |
2007年 | 2390篇 |
2006年 | 2360篇 |
2005年 | 2556篇 |
2004年 | 2294篇 |
2003年 | 2128篇 |
2002年 | 2167篇 |
2001年 | 568篇 |
2000年 | 491篇 |
1999年 | 520篇 |
1998年 | 495篇 |
1997年 | 471篇 |
1996年 | 432篇 |
1995年 | 417篇 |
1994年 | 346篇 |
1993年 | 352篇 |
1992年 | 359篇 |
1991年 | 391篇 |
1990年 | 393篇 |
1989年 | 346篇 |
1988年 | 316篇 |
1987年 | 335篇 |
1986年 | 282篇 |
1985年 | 283篇 |
1984年 | 317篇 |
1983年 | 299篇 |
1982年 | 332篇 |
1981年 | 320篇 |
1980年 | 268篇 |
1979年 | 197篇 |
1978年 | 205篇 |
1977年 | 145篇 |
1976年 | 145篇 |
1975年 | 121篇 |
1974年 | 150篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Bruce Becker MD Robert Woolard MD Ted D. Nirenberg PhD P. Allison Minugh PhD Richard Longabaugh EdD Patrick R. Clifford PhD 《Academic emergency medicine》1995,2(9):784-790
Objectives: To determine the incidence of alcohol use in subcritically injured patients presenting to the ED, by using a saliva alcohol test (SAT) at ED triage during the ED initial assessment; to compare the incidence of alcohol use revealed by the SAT with documentation of alcohol use by ED nurses and emergency physicians (EPs) blinded to the SAT results; and to describe the demographics of the SAT-positive, subcritically injured population.
Methods: A blinded, prospective, observational evaluation of ED patients presenting with subcritical injuries was performed. The patients were tested for alcohol use with an SAT, and a subsequent record review was conducted for extraction of demographic data and evidence of documentation of alcohol use by ED nurses and EPs blinded to the SAT results.
Results: During the study. 791 subcritically injured patients had SATs performed. Twenty-one percent of these patients were found to be alcohol-positive by SAT. Either the ED nurse or the EP documented a clinical impression of alcohol use for 52% of the SAT-positive patients. There were higher SAT-positive rates among men (24%), victims of assault (47%), and patients arriving at night (41%).
Conclusions: While the SAT identified 21% of the subcritically injured patient population as alcohol-positive, ED nurse and EP documentation did not identify half of these alcohol-positive patients. Many of these patients may be at risk for additional injuries related to their drinking behavior. 相似文献
Methods: A blinded, prospective, observational evaluation of ED patients presenting with subcritical injuries was performed. The patients were tested for alcohol use with an SAT, and a subsequent record review was conducted for extraction of demographic data and evidence of documentation of alcohol use by ED nurses and EPs blinded to the SAT results.
Results: During the study. 791 subcritically injured patients had SATs performed. Twenty-one percent of these patients were found to be alcohol-positive by SAT. Either the ED nurse or the EP documented a clinical impression of alcohol use for 52% of the SAT-positive patients. There were higher SAT-positive rates among men (24%), victims of assault (47%), and patients arriving at night (41%).
Conclusions: While the SAT identified 21% of the subcritically injured patient population as alcohol-positive, ED nurse and EP documentation did not identify half of these alcohol-positive patients. Many of these patients may be at risk for additional injuries related to their drinking behavior. 相似文献
82.
V. A. Dunand C.-M. Ng J. A. Wade J. Bwayo F. A. Plummer K. S. MacDonald 《Tissue antigens》1997,49(4):397-402
The genes of the major histocompatibility complex (MHC) are amongst the most polymorphic loci known in the human population. The population genetics of the MHC encoded HLA loci of sub-Saharan Africa are of major interest because of their particular genetic diversity. Here we report on the HLA-DR 52- and 51-associated determinants of the DRB1 loci observed in 165 East African individuals studied in Nairobi, Kenya. The HLA-DR typing was done by serologic and by molecular DNA techniques (PCR-SSOP). The most frequent allele identified was DRB1*1101, followed by DRB1*1503 and DRB1*1302. Some unexpected alleles were repeatedly identified: DRB1*1108, DRB1*1316 and DRB1*1421. Most oftheDR 52-and 51-associated DRB1 alleles were correctly identified by serology as part of the DR3, DR5, DR6 and DR2 groups respectively. The HLA-DRB1 profile reported here corroborates previous genetic and linguistic data supporting the concept that the Eastern African Black population is genetically distinct from other African Black populations. This has important implications in public health issues related to the genetic profile of a population (transplantation, vaccine design for example). 相似文献
83.
J. Randolph Swartz Ira M. Lesser Kyle B. Boone Bruce L. Miller Ismael Mena 《International journal of geriatric psychiatry》1995,10(6):437-446
Global and regional cerebral blood flow (CBF) were evaluated with single photon emission computerized tomography (SPECT) utilizing both 133Xenon (133Xe) (47 subjects, 47–82 years old) and 99Tc-hexamethylpropyleneamine oxime (99Tc-HMPAO) (27 subjects, 47–80 years old). The 133Xe results showed: among total subjects, no age-related decline in global CBF, but a significant regional decline in the occipital lobe (p < 0.05); among men, significant age-related declines in global, frontal, temporal, occipital and right hemisphere CBF (all p < 0.05); among women, no age-related decline in global or regional CBF. The 99Tc-HMPAO results showed no age-related decline in either global or regional perfusion among total subjects, men or women. These results suggest that age-related global and regional (including frontal lobe) CBF declines do not occur in healthy control subjects after the age of 45 years. However, gender differences in age-related CBF changes warrant further study. 相似文献
84.
Six of 175 Angus heifers died after ingesting excessive amounts of Durango root (Datisca glomerata). Animals had rumens full of Durango root, were extremely lethargic, and had diarrhea prior to death. The animals had nonspecific postmortem lesions. This case is discussed in light of previous findings from trials in which Durango root was experimentally fed to cattle. 相似文献
85.
This study was designed to determine the effect of dietary carbohydrate and fiber on mucosal insulin receptors, in order to correlate changes in cellular proliferation with hormonal responsiveness. In two protocols insulin binding was significantly affected by the consumption of dietary fiber. Compared to fiber-free, feeding corn bran increased binding in the duodenum 30% and ileum 50% but decreased binding in the jejunum 44%, and feeding guar gum increased binding in the colon 73% but decreased binding in the jejunum 40%. Feeding wheat bran or oat bran increased binding 50% in the small intestine compared to cellulose or fiber-free. Receptor autophosphorylation was 30% higher with fiber-free or wheat bran feeding than cellulose or oat bran. These changes in receptor binding and activity may correlate with altered rates of cell proliferation induced by dietary fiber. 相似文献
86.
Active and passive surveillance for communicable diseases in child care facilities, Seattle-King County, Washington.
下载免费PDF全文
![点击此处可从《American journal of public health》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J K MacDonald J Boase L K Stewart E R Alexander S L Solomon R L Cordell 《American journal of public health》1997,87(12):1951-1955
OBJECTIVES: The purpose of this study was to develop and evaluate models for public health surveillance of illnesses among children in out-of-home child care facilities. METHODS: Between July 1992 and March 1994, 200 Seattle-King County child care facilities participated in active or enhanced passive surveillance, or both. Reporting was based on easily recognized signs, symptoms, and sentinel events. Published criteria were used in evaluating surveillance effectiveness, and notifiable disease reporting of participating and nonparticipating facilities was compared. RESULTS: Neither surveillance model was well accepted by child care providers. Enhanced passive and active surveillance had comparable sensitivity. Reporting delays and the large amount of time needed for data entry led to problems with timeliness, especially in terms of written reporting during active surveillance. CONCLUSIONS: Widespread active public health surveillance in child care facilities is not feasible for most local health departments. Improvements in public health surveillance in child care settings will depend on acceptability to providers. 相似文献
87.
The Workup for Bariatric Surgery Does Not Require a Routine Upper Gastrointestinal Series 总被引:1,自引:0,他引:1
Andrew J Ghassemian Kenneth G MacDonald MD Paul G Cunningham MD Melvin Swanson PhD Brenda M Brown MRA Patricia G Morris BSN Walter J Pories MD 《Obesity surgery》1997,7(1):16-18
Background: Morbid obesity is a serious disease that afflicts over five million Americans, threatening their health with such
co-morbidities as diabetes, arthritis, pulmonary failure and stroke. Surgery is the only effective therapy, providing long-term
control of weight, diabetes, pulmonary failure, and hypertension for as long as 14 years. Because the operation presents a
major expense, this study examined whether X-ray examination of the gut could be omitted safely as a cost-saving measure.
Methods: The records of 814 consecutive morbidly obese patients who underwent gastric bypass were reviewed to determine: (1)
whether these individuals had undergone an upper gastro-intestinal (GI) series, and (2) if these studies influenced therapy
or caused cancellation or postponement of surgery. Results: Of the 814 patients, 657 (80.7%) underwent a preoperative GI radiography.
Of these examinations, 393 (59.8%) were normal, with the following abnormalities in the remaining 264: hiatal hernia, 164;
esophageal reflux, 39; Schatzki's ring, 18; small bowel diverticula, four; renal stones, four; malrotation, three; gall stones,
two; pyloric ulcer, one; possible pelvic mass, one; calcified leiomyoma, one; and dysphagial lusoria, one. None of these findings
resulted in cancellation or a delay in surgery. Conclusions: The upper GI series can be safely omitted from the routine preoperative
evaluation of patients undergoing gastric bypass. At a cost of $741.00 per examination, this change represents significant
potential savings. Similar evaluations of other routine preoperative tests may well provide a better basis for the evaluation
of these complex patients. 相似文献
88.
89.
90.
Dr. David M. Euhus MD Lucille Kimura PhD Bruce Arnold MD 《Annals of surgical oncology》1997,4(5):432-439
Background: Mice immunized with murine mammary carcinoma cells genetically engineered to secrete interleukin-2 (IL-2) are rendered resistant
to subsequent challenge with unmodified tumor cells, and in the case of mice bearing established tumors, the rate of development
of pulmonary metastases is reduced. Despite these encouraging animal results, little is known about the induction of antitumor
immunity by IL-2 gene transfer in human breast cancer.
Methods: Adenovirally mediated IL-2 gene transfer was performed in 12 tumor fragment cultures established from seven primary breast
cancers. Autologous tumor infiltrating lymphocytes (TILs) or peripheral blood mononuclear cells (PBMCs) were cocultured with
transduced tumor fragments, and changes in phenotype and cytotoxicity were measured.
Results: IL-2 was never detectable in the untransduced cultures, but it peaked at 5.0—1,324.8 ng/ml in the transduced cultures. Lymphocyte
counts declined in all untransduced cultures, but they increased two- to sevenfold in four transduced cultures. CD4:CD8 ratios
decreased from a mean of 2.11 at baseline to 1.27 after stimulation in coculture (p=0.03). Expansion of lymphocytes expressing
the natural killer cell phenotype (CD3−CD56+) occurred in only one culture, but the CD3+CD56+ population increased in four of six cultures. Lymphocytes from four of 10 cocultures generated significant cytotoxicity against
allogeneic breast cancer cells. Induction of cytotoxicity correlated with expansion of the CD3+CD56+ phenotype (R2=0.805, p=0.02).
Conclusions: IL-2 gene expression by human breast cancer causes expansion of CD3+CD56+ cytotoxic lymphocytes. This phenotype is consistent with that of a non-major histocompatibility complex (MHC)-restricted
cytokine induced killer cell population previously described.
Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the
U.S. Army.
Presented at the 49th Annual Cancer Symposium of The Society of Surgical Oncology, Atlanta, Georgia, March 21–24, 1996. 相似文献