全文获取类型
收费全文 | 1700篇 |
免费 | 129篇 |
国内免费 | 159篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 50篇 |
妇产科学 | 54篇 |
基础医学 | 190篇 |
口腔科学 | 29篇 |
临床医学 | 221篇 |
内科学 | 309篇 |
皮肤病学 | 16篇 |
神经病学 | 197篇 |
特种医学 | 33篇 |
外科学 | 332篇 |
综合类 | 19篇 |
一般理论 | 2篇 |
预防医学 | 283篇 |
眼科学 | 7篇 |
药学 | 81篇 |
肿瘤学 | 150篇 |
出版年
2023年 | 13篇 |
2022年 | 24篇 |
2021年 | 64篇 |
2020年 | 40篇 |
2019年 | 69篇 |
2018年 | 55篇 |
2017年 | 28篇 |
2016年 | 55篇 |
2015年 | 55篇 |
2014年 | 80篇 |
2013年 | 85篇 |
2012年 | 141篇 |
2011年 | 141篇 |
2010年 | 70篇 |
2009年 | 67篇 |
2008年 | 101篇 |
2007年 | 132篇 |
2006年 | 103篇 |
2005年 | 101篇 |
2004年 | 107篇 |
2003年 | 91篇 |
2002年 | 97篇 |
2001年 | 50篇 |
2000年 | 43篇 |
1999年 | 33篇 |
1998年 | 27篇 |
1997年 | 17篇 |
1996年 | 4篇 |
1995年 | 11篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1977年 | 5篇 |
1975年 | 2篇 |
1961年 | 1篇 |
1945年 | 1篇 |
1932年 | 1篇 |
排序方式: 共有1988条查询结果,搜索用时 15 毫秒
101.
Kenagy GP 《Health & social work》2005,30(1):19-26
HIV/AIDS, suicide, violence, and barriers to health care access among transgender people were explored using two needs assessment surveys conducted in Philadelphia in 1997. A total of 182 people responded to a face-to-face interview or self-administered mail survey: 113 male-to-female individuals and 69 female-to-male individuals. About three-fifths of respondents had engaged in unprotected sexual activity during the past 12 months. The risk for HIV infection from unprotected sex was significantly higher among respondents of color than among white respondents. About one-third (30.1 percent) of respondents had attempted suicide. More than half of respondents had been forced to have sex, 56.3 percent had experienced violence in their homes, and 51.3 percent had been physically abused. Twenty-six percent of respondents had been denied medical care because they were transgender. These findings suggest that prevention services that specifically address HIV/AIDS, suicide, and violence among transgender people are urgently needed. 相似文献
102.
OBJECTIVE: To examine university students' attitudes, behaviors, and beliefs related to hazing. METHODS: A random and representative sample of students completed a web-based survey regarding team-building and initiation behaviors (N=736). RESULTS: Thirty-six percent of the respondents participated in hazing. Greeks, males, varsity athletes, leaders, and upperclassmen were more likely to engage in hazing. Students who engaged in hazing were more likely to engage in positive team-building activities. CONCLUSIONS: Hazing is occurring on campus, although not always recognized as such by students. Various factors that would enable someone to stop a hazing situation are addressed. 相似文献
103.
A combination of prebiotic short- and long-chain inulin-type fructans enhances calcium absorption and bone mineralization in young adolescents 总被引:1,自引:0,他引:1
Abrams SA Griffin IJ Hawthorne KM Liang L Gunn SK Darlington G Ellis KJ 《The American journal of clinical nutrition》2005,82(2):471-476
BACKGROUND: Short-term studies in adolescents have generally shown an enhancement of calcium absorption by inulin-type fructans (prebiotics). Results have been inconsistent; however, and no studies have been conducted to determine whether this effect persists with long-term use. OBJECTIVE: The objective was to assess the effects on calcium absorption and bone mineral accretion after 8 wk and 1 y of supplementation with an inulin-type fructan. DESIGN: Pubertal adolescents were randomly assigned to receive 8 g/d of a mixed short and long degree of polymerization inulin-type fructan product (fructan group) or maltodextrin placebo (control group). Bone mineral content and bone mineral density were measured before randomization and after 1 y. Calcium absorption was measured with the use of stable isotopes at baseline and 8 wk and 1 y after supplementation. Polymorphisms of the Fok1 vitamin D receptor gene were determined. RESULTS: Calcium absorption was significantly greater in the fructan group than in the control group at 8 wk (difference: 8.5 +/- 1.6%; P < 0.001) and at 1 y (difference: 5.9 +/- 2.8%; P = 0.04). An interaction with Fok1 genotype was present such that subjects with an ff genotype had the least initial response to fructan. After 1 y, the fructan group had a greater increment in both whole-body bone mineral content (difference: 35 +/- 16 g; P = 0.03) and whole-body bone mineral density (difference: 0.015 +/- 0.004 g/cm(2); P = 0.01) than did the control group. CONCLUSION: Daily consumption of a combination of prebiotic short- and long-chain inulin-type fructans significantly increases calcium absorption and enhances bone mineralization during pubertal growth. Effects of dietary factors on calcium absorption may be modulated by genetic factors, including specific vitamin D receptor gene polymorphisms. 相似文献
104.
Fawzi WW Villamor E Msamanga GI Antelman G Aboud S Urassa W Hunter D 《The American journal of clinical nutrition》2005,81(1):161-167
BACKGROUND: In observational studies, the zinc status of HIV-infected persons has been associated with both positive and adverse clinical outcomes. Such endpoints may affect the risk of adverse birth outcomes among HIV-infected women. OBJECTIVE: We examined the effects of zinc supplements on birth outcomes, hematologic indicators, and counts of T lymphocyte subsets among 400 HIV-infected pregnant women. DESIGN: Eligible women between 12 and 27 wk of gestation were randomly assigned to daily oral supplementation with either 25 mg Zn or placebo between recruitment and 6 wk after delivery. All women received iron, folic acid, and multivitamin supplements irrespective of the experimental assignment. RESULTS: We observed no significant differences in birth weight, duration of gestation, or fetal and neonatal mortality between women in the zinc and placebo groups. Hemoglobin concentrations increased between baseline and 6 wk postpartum in both groups. However, the rise in hemoglobin over this period was significantly lower (P = 0.03) in the zinc group (x +/- SD: 11.5 +/- 17.9 g/L) than in the placebo group (15.2 +/- 18.6 g/L). Similarly, the changes in red blood cell count and in packed cell volume over the same period were significantly lower in the zinc group (P < 0.01 and P = 0.01, respectively). Zinc had no effect on CD4(+), CD8(+), or CD3(+) cell counts during the follow-up period. CONCLUSION: Because of the lack of beneficial effects of zinc on adverse pregnancy outcomes and the likelihood of negative effects on hemoglobin concentrations, no compelling evidence exists to support the addition of zinc to prenatal supplements intended for pregnant HIV-infected women. 相似文献
105.
While the protective nature of parity with respect to ovarian cancer has been well documented, whether a history of incomplete pregnancy affects ovarian cancer risk is uncertain. Data collected from 739 epithelial ovarian cancer cases and 1,313 community controls in the Delaware Valley from 1994 to 1998 were used to evaluate the relation between gestational length and timing of first induced or spontaneous abortion and ovarian cancer risk. Incomplete pregnancy was not associated with ovarian cancer among nulliparous women or among ever-pregnant women either before or after adjustment for relevant confounders (for nulliparous women, odds ratio (OR) = 1.12, 95% confidence interval (CI): 0.66, 1.89; for ever-pregnant women, OR = 0.95, 95% CI: 0.76, 1.18). Among unigravid women, one full-term pregnancy was more protective than an incomplete pregnancy (adjusted OR = 0.29, 95% CI: 0.15, 0.57). These results were independent of the type of pregnancy loss. Among ever-pregnant women, a spontaneous abortion before a first birth provided significant protection (adjusted OR = 0.47, 95% CI: 0.30, 0.75), while no significant effect was found for an induced abortion prior to a first birth (adjusted OR = 0.80, 95% CI: 0.44, 1.47). These data do not support an independent association between incomplete pregnancies, either spontaneous or induced, and ovarian cancer risk. 相似文献
106.
107.
LeResche L Sherman JJ Huggins K Saunders K Mancl LA Lentz G Dworkin SF 《Journal of orofacial pain》2005,19(3):193-201
AIMS: To describe the course of reported musculoskeletal pain in the temporomandibular region and other signs and symptoms of temporomandibular disorders (TMD) as well as psychological distress over the course of pregnancy and 1 year postpartum. METHODS: Women with musculoskeletal orofacial pain (n = 19) and pain-free comparison subjects (n = 16) in the first trimester of pregnancy were selected through records review from the population of a large health maintenance organization. Subjects completed a self-administered questionnaire assessing pain, depression, and somatic symptoms; provided a sample of whole unstimulated saliva; and underwent a standardized clinical examination during the third, sixth, and ninth months of pregnancy and 1 year postpartum. RESULTS: At baseline (third month of pregnancy), 16 of the 19 patients with musculoskeletal orofacial pain met criteria for an RDC/TMD diagnosis. Reported musculoskeletal orofacial pain diminished significantly during the second or third trimester of pregnancy and increased again postpartum. Measures of mandibular opening increased over pregnancy in both cases and comparison subjects and remained high postpartum. Depression and somatic symptoms changed little over the course of pregnancy but were substantially lowered at 1 year postpartum for both groups. As expected, subjects with pain had higher levels of palpation pain, diminished mandibular range of motion, and higher levels of psychological distress compared to subjects without orofacial pain. CONCLUSION: Musculoskeletal orofacial pain and related symptoms appear to improve over the course of pregnancy. This improvement occurs in the presence of increased joint laxity and is not paralleled by improvements in psychological distress. Thus, it was concluded that the improvement in pain is most likely associated with the dramatic hormonal changes occurring during pregnancy. 相似文献
108.
Gimpel GA Collett BR Veeder MA Gifford JA Sneddon P Bushman B Hughes K Odell JD 《Clinical pediatrics》2005,44(5):405-411
The effect that treatment with stimulant medication has on the intellectual performance of children with attention deficit hyperactivity disorder (ADHD) was examined. Thirty-one children diagnosed with ADHD were given a WISC-III before any treatment was implemented. At least 1 year later, children were retested. At this time, 24 of the children were taking stimulant medications. Children receiving medications had significant increases in IQ scores, but no changes were found for those not taking medications. Changes in IQ scores were moderately related to parents' perceived efficacy of the medication and parent-reported compliance with medication but were not strongly related to changes in parent-reported ADHD symptoms. 相似文献
109.
110.