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   14812篇
  免费   960篇
  国内免费   37篇
耳鼻咽喉   126篇
儿科学   608篇
妇产科学   462篇
基础医学   2137篇
口腔科学   256篇
临床医学   2055篇
内科学   2388篇
皮肤病学   284篇
神经病学   1656篇
特种医学   267篇
外科学   1011篇
综合类   157篇
现状与发展   1篇
一般理论   37篇
预防医学   2198篇
眼科学   208篇
药学   810篇
中国医学   11篇
肿瘤学   1137篇
  2023年   144篇
  2022年   181篇
  2021年   342篇
  2020年   253篇
  2019年   371篇
  2018年   372篇
  2017年   336篇
  2016年   293篇
  2015年   355篇
  2014年   508篇
  2013年   799篇
  2012年   1103篇
  2011年   1147篇
  2010年   582篇
  2009年   544篇
  2008年   992篇
  2007年   975篇
  2006年   1009篇
  2005年   997篇
  2004年   905篇
  2003年   834篇
  2002年   826篇
  2001年   107篇
  2000年   65篇
  1999年   107篇
  1998年   189篇
  1997年   149篇
  1996年   106篇
  1995年   110篇
  1994年   93篇
  1993年   77篇
  1992年   76篇
  1991年   48篇
  1990年   49篇
  1989年   39篇
  1988年   36篇
  1987年   24篇
  1986年   46篇
  1985年   43篇
  1984年   55篇
  1983年   65篇
  1982年   82篇
  1981年   53篇
  1980年   50篇
  1979年   31篇
  1978年   33篇
  1977年   21篇
  1976年   19篇
  1974年   22篇
  1973年   15篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
MenBvac and Menjugate are safe and efficacious vaccines. The purpose of this study was to evaluate safety and immunogenicity of the combination (MenB/C) of the lyophilized active components of the conjugated group C vaccine Menjugate when reconstituted with the full liquid group B outer membrane vesicle vaccine MenBvac compared to MenBvac and Menjugate given separately. At 6-week intervals, healthy adults were given one dose of MenB/C followed by two doses of MenBvac (MenB/C group), three doses of MenBvac (MenB group), or one dose of Menjugate and two doses of placebo (MenC group). Injection site reactions were frequent in all groups. However, most reactions were short lasting and mild or moderate in intensity, and the vaccines were found to be well tolerated, with no vaccine-related serious adverse events. MenB/C was immunogenic with regard to both serogroup B and C meningococci. Both the serum bactericidal assay and the enzyme-linked immunosorbent assay analyses showed that the immune responses of the combination vaccine were similar to the immune responses of its separate components MenBvac and Menjugate for both serogroup B and C. In conclusion, the combined MenB/C vaccine is safe and immunogenic. The two vaccines do not interact negatively with each other and can easily be administered in the same syringe. The induced immune responses suggest that the combined vaccine is likely to confer protection against systemic group B disease caused by the vaccine strain as well as against group C meningococcal disease.  相似文献   
52.
Physical illness is a life experience which challenges an individual'ssense of control and thus represents a potential threat to mentalhealth. For children, a serious illness threatens not only theirsense of physical and psychological well-being but also threatensthe psychological well-being of their family. In this study,severely ill patients (n = 15) and a member of their family(n = 15) were interviewed. The patients, who ranged in age from12 to 21 years, were being treated for metastatic solid tumorsor lymphoma that failed to respond to conventional therapeuticregimens. Correlates of control for the patients and familymembers, the relationship between control and developmentalstage of the patients, and the difference between levels ofcontrol in patients and family member were examined. The findingsare discussed in relation to development and their implicationsfor medical management.  相似文献   
53.
Partial trisomy 22: A recognizable syndrome   总被引:3,自引:0,他引:3  
A patient identified as being a partial trisomy 22 mosaic is presented. The presence of a translocation t(4;22) (pter;q12) is noted in the mother, sister and maternal aunt. Comparison is made with nine other reported cases of partial trisomy 22 confirmed by parental translocation. These suggest a definite syndrome, including mental retardation, congenital heart disease, skeletal anomalies, anti-mongoloid slant of the palpebral fissures, preauricular skin tags and low-set ears.  相似文献   
54.
55.
56.
Self-report symptoms of anxiety are widely used in mental health and social science research as an index of current psychiatric state. Previous twin studies have suggested that genetic factors account for a significant proportion of the variance in these symptoms. To replicate and extend these findings, we examined self-report symtoms of panic-phobia and somatization in the “Virginia 30,000” twin-family sample. Model fitting applied to 80 unique relationships in the twin-family pedigree produced the following major results: (i) genetic effects were significant for both symptom factors, accounting for between 25 and 49% of the total variance, with the exception of symptoms of panic-phobia in females, where they accounted for 15–16% of the variance; (ii) familial environmental effects were absent for symptoms of somatization, while for symptoms of panic-phobia they accounted for a very small proportion of variance in males (≤1.2%) and a modest proportion in females (6–17%) (iii) spousal correlations were present for both factors, ranging from +0.05 to +0.20; (iv) genetic factors which influenced symptoms were generally the same in males and females, although their effect was greater in males; (v) heritability estimates were lower in the population-based than in the volunteer sample; and (vi) when test-retest reliability was included in the model, results suggest that genetic factors account for at least half of the stable variance for all symptom factors, except panic-phobia in females. Our results support the validity of previous twin studies of self-report symptoms of anxiety and suggest that genetic factors significantly influence these symptoms but familial-environmental factors play little or no etiologic role.  相似文献   
57.
Mature cystic teratomas of the ovary frequently contain intestinal type epithelium, but they are rarely associated with complete intestinal wall. The association of mature cystic teratoma with mucinous cystadenoma is not unusual. However, the pathogenetic relationship between these two lesions remains unanswered. We report a mature cystic teratoma of the ovary in a 16-yr old female that contained a complete colonic wall in continuity with an endocervical-type mucinous cystadenoma. Both the mucinous cystadenoma and the colonic wall showed the typical histopathological and immunohistochemical patterns of classical mucinous cystadenoma (positive for CK7, negative for CK20) and normal colonic wall (positive for CK20, negative for CK7), respectively. The microscopic and immunohistochemical patterns of the epithelium from the transitional zone between colonic wall-like structure and mucinous cystadenoma demonstrated features of both types of epithelium, positive for both CK7 and CK20, and focally positive for a neuroendocrine marker, chromogranin, which is normally present in colonic mucosa. These results suggest that the mucinous cystadenoma originated from the colonic epithelium of the mature cystic teratoma.  相似文献   
58.
Summary When the loss of body heat is accelerated by exposure to low environmental temperatures, additional substrates must be oxidized to provide energy to sustain temperature homeostasis. Therefore, the present investigation examined the relation between feeding regime [pre-experimental carbohydrate feeding (FED) vs a fast (FAST)], during 120 min of exposure to 8, 20, and 27° C in well-nourished men. The following were examined: tissue insulation (I; °C · m2 · W–1), rectal temperature (T re; °C), and oxygen consumption ( O2; ml · kg–1 · min–1). O2, T re, and I revealed no significant differences between treatments (FED vs FAST) at any temperature. At 27° C, I was less (P < 0.05) than at 20 and 8° C, and decreased (P < 0.05) as exposure time increased. At 8° C, O2was higher (P < 0.5) than at 20 or 27°C, and O2increased as time increased (P < 0.05). T re decreased (P < 0.05) as time increased for all conditions. Respiratory exchange ratio (R) differed (P < 0.05) between treatments (FED vs FAST), temperature (8 vs 20° C), and across time. Values for R suggests that carbohydrate accounted for 56% and 33% of caloric utilization during the FED vs FAST conditions, respectively. At 8 vs 20° C, R represented 54% vs 30% of cabohydrate utilization. Across time, R demonstrated that in both conditions (FED vs FAST) there was a decreased reliance on carbohydrate utilization for energy provision. From these data it appears that while substrate utilization differed between dietary treatment and across time this did not differentially affect O2or T re during protracted exposure to 8, 20, and 27° C. The higher R in the 8° C condition for both dietary treatments demonstrates that carbohydrate utilization is increased in shivering cold-exposed humans. However, the reduction in R across time suggests that fat oxidation is also involved in metabolic heat production and core temperature maintenance during shivering in the cold.  相似文献   
59.
60.
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