全文获取类型
收费全文 | 11911篇 |
免费 | 762篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 76篇 |
儿科学 | 420篇 |
妇产科学 | 232篇 |
基础医学 | 1385篇 |
口腔科学 | 157篇 |
临床医学 | 1304篇 |
内科学 | 2002篇 |
皮肤病学 | 148篇 |
神经病学 | 1551篇 |
特种医学 | 548篇 |
外科学 | 2009篇 |
综合类 | 123篇 |
一般理论 | 23篇 |
预防医学 | 1141篇 |
眼科学 | 110篇 |
药学 | 830篇 |
中国医学 | 24篇 |
肿瘤学 | 613篇 |
出版年
2023年 | 62篇 |
2022年 | 92篇 |
2021年 | 245篇 |
2020年 | 164篇 |
2019年 | 271篇 |
2018年 | 310篇 |
2017年 | 209篇 |
2016年 | 252篇 |
2015年 | 242篇 |
2014年 | 428篇 |
2013年 | 590篇 |
2012年 | 906篇 |
2011年 | 952篇 |
2010年 | 528篇 |
2009年 | 485篇 |
2008年 | 831篇 |
2007年 | 803篇 |
2006年 | 785篇 |
2005年 | 829篇 |
2004年 | 757篇 |
2003年 | 719篇 |
2002年 | 651篇 |
2001年 | 102篇 |
2000年 | 71篇 |
1999年 | 93篇 |
1998年 | 140篇 |
1997年 | 102篇 |
1996年 | 104篇 |
1995年 | 90篇 |
1994年 | 71篇 |
1993年 | 54篇 |
1992年 | 59篇 |
1991年 | 45篇 |
1990年 | 34篇 |
1989年 | 41篇 |
1988年 | 57篇 |
1987年 | 42篇 |
1986年 | 38篇 |
1985年 | 30篇 |
1984年 | 46篇 |
1983年 | 45篇 |
1982年 | 47篇 |
1981年 | 33篇 |
1980年 | 48篇 |
1979年 | 26篇 |
1978年 | 20篇 |
1977年 | 19篇 |
1976年 | 21篇 |
1972年 | 14篇 |
1971年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
Posttraumatic stress disorder and associated risk factors in Canadian peacekeeping veterans with health-related disabilities. 总被引:2,自引:0,他引:2
OBJECTIVES: This study investigates posttraumatic stress disorder (PTSD) and its associated risk factors in a random, national, Canadian sample of United Nations peacekeeping veterans with service-related disabilities. METHODS: Participants included 1016 male veterans (age < 65 years) who served in the Canadian Forces from 1990 to 1999 and were selected from a larger random sample of 1968 veterans who voluntarily and anonymously completed a general health survey conducted by Veterans Affairs Canada in 1999. Survey instruments included the PTSD Checklist-Military Version (PCL-M), Center for Epidemiological Studies-Depression Scale (CES-D), and questionnaires regarding life events during the past year, current stressors, sociodemographic characteristics, and military history. RESULTS: We found that rates of probable PTSD (PCL-M score > 50) among veterans were 10.92% for veterans deployed once and 14.84% for those deployed more than once. The rates of probable clinical depression (CES-D score > 16) were 30.35% for veterans deployed once and 32.62% for those deployed more than once. We found that, in multivariate analyses, probable PTSD rates and PTSD severity were associated with younger age, single marital status, and deployment frequency. CONCLUSIONS: PTSD is an important health concern in the veteran population. Understanding such risk factors as younger age and unmarried status can help predict morbidity among trauma-exposed veterans. 相似文献
3.
Outcomes at 3 years of a prospective pilot study of Campath-1H and sirolimus immunosuppression for renal transplantation 总被引:2,自引:0,他引:2
Rolf N. Barth Christina A. Janus Christine A. Lillesand Nancy A. Radke John D. Pirsch Bryan N. Becker Luis A. Fernandez L. Thomas Chin Yolanda T. Becker Jon S. Odorico Anthony M. D''Alessandro Hans W. Sollinger Stuart J. Knechtle 《Transplant international》2006,19(11):885-892
Campath-1H (alemtuzumab) induction was used for renal transplantation in combination with sirolimus as immunosuppression. We previously reported a high (28%) rate of early rejection with this regimen, and now report 3-year outcomes. Twenty-nine patients were recipients of either deceased donor or non-HLA (Human Leukocyte Antigen) identical living donor primary renal allografts. Clinical parameters including infection, malignancy, kidney function, and kidney histology were followed prospectively for 3 years. Three-year cumulative graft and patient survival were 96% and 100%, respectively. Twenty patients were maintained on steroid-free immunosuppressive regimens, and 15 patients were maintained on monotherapy for immunosuppression (12 on sirolimus). No serious infectious complications were observed and two patients developed basal cell skin cancer. The 3-year results of our initial pilot study demonstrate good graft (96%) and patient (100%) outcomes. Campath-1H induction has yielded a high proportion of patients maintained on immunosuppressive monotherapy (57%) without serious infectious- and no malignancy-related complications. The reported regimen yielded novel insights into both Campath-1H and sirolimus therapy in renal transplantation. Because of the higher incidence of early rejection, we recommend a modified strategy of immunosuppression including a brief course of a calcineurin inhibitor. 相似文献
4.
5.
Monolayer cultures of normal human bone cells contain multiple subpopulations of alkaline phosphatase positive cells 总被引:5,自引:0,他引:5
Toshikatsu Matsuyama K. -H. William Lau Jon E. Wergedal 《Calcified tissue international》1990,47(5):276-283
Summary Cytochemical staining of normal human bone cells in monolayer cultures for alkaline phosphatase (ALP) indicated that the cultures
contained mixed-cell populations. Time course evaluations of the cytochemical staining revealed, in addition to the ALP-negative
cell population, at least two subpopulations of ALP-positive human bone cells with different levels of ALP. A cytochemical
method has been developed which separates the ALP-positive cells into high and intermediate ALP subpopulations. In this method,
human bone cells were stained for ALP using an azo-dye method and incubating at 4°C for 10 and 30 minutes, respectively. We
defined the cell population that stained positively for ALP at 10 minutes as strong ALP-positive cells, and both strong and
intermediate cells were stained at 30 minutes. The intermediate cells were determined from the difference between the values
at the two time points. The intra- and interassay variations of the assay, with the same investigator in blinded investigations,
were both less than 10% and the interobserver variation was approximately 25%. Analysis of the distribution of ALP levels
in cells with a laser densitometer confirmed the presence of at least three cell subpopulations. 1,25(OH)2D3 treatment increased the proportions of both ALP-positive cell populations, whereas TGF-beta treatment increased only the
intermediate ALP-positive cell population. On the contrary, fluoride increased the proportion of the strong ALP cells, and
IGF-1 had no effect on the proportions of either ALP-positive subpopulation. When the ALP-specific activity was compared with
the percentage of each ALP-positive subpopulations for the cells treated with effectors, the ALP-specific activity correlated
with the total ALP-positive and with the strong ALP-positive populations but not with the intermediate ALP-positive subpopulation.
In summary, this study represents the first evidence that normal human bone cells in monolayer cultures contained at least
two subpopulations of ALP-positive cells, and that bone cell effectors could have differential effects on each cell population. 相似文献
6.
D. Caroline Blanchard Jon K. Shepherd Antonio De Padua Carobrez Robert J. Blanchard 《Neuroscience and biobehavioral reviews》1991,15(4):461-468
Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety. 相似文献
7.
Frank Lindseth Thomas Lang? Jon Bang Toril A Nagelhus Hernes 《Computer aided surgery》2002,7(4):197-222
8.
9.
10.
Jon Artun Faraj Behbehani Badreia Al-Jame Heidi Kerosuo 《American journal of orthodontics and dentofacial orthopedics》2005,128(3):347-352
INTRODUCTION: Incisor trauma is a significant clinical problem in children and adolescents. The purposes of this study were to report on the prevalence and severity of incisor trauma in a large population-based sample of adolescent Kuwaiti residents in the early permanent dentition, to determine the ages of and reasons for the injuries, and to test for any effects of sex, incisor occlusion, and lip coverage on the prevalence of incisor trauma. METHODS: Presence and type of traumatic injury were scored according to the National Institute of Dental Research index in a population-based sample of 795 girls and 788 boys with a mean age of 13.24 years (SD 0.42). RESULTS: Trauma prevalence was higher (P < .001) in boys (19.3%) than in girls (9.7%), and in the maxilla (13.6%) than in the mandible (1.5%). Most (77.3 %) of the affected subjects had only 1 injured tooth, and most (83.7%) of the traumatized teeth were maxillary central incisors. A total of 90.3% of the injuries were unrepaired enamel or enamel/dentin fractures. The major reasons for the injuries were falls and blows indoors (48.4%) or outdoors (41.6%). Nearly two-thirds (63.0%) of the traumas occurred at age 10 years or later. Mean overjet (OJ) was larger (3.9 v 3.0 mm, P < .01), and lip incompetence more frequent (12.7% v 7.3%, P < .01) among the subjects with injured maxillary incisors than among those without. Logistic regression showed that the odds of maxillary incisor trauma were 2.8 times higher in subjects with OJ between 6.5 and 9.0 mm, and 3.7 times higher in subjects with OJ > or = 9.5 mm than in subjects with OJ < or = 3.5 mm. CONCLUSIONS: Multiple logistic regression showed that the risk of maxillary incisor trauma was about 2 times higher in boys than in girls, and that the risk increased by 13% for every millimeter of increase in OJ. Lip competence was not included in the model. No associations were found between occlusion and mandibular incisor trauma. 相似文献