全文获取类型
收费全文 | 1859篇 |
免费 | 155篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 72篇 |
妇产科学 | 73篇 |
基础医学 | 253篇 |
口腔科学 | 13篇 |
临床医学 | 206篇 |
内科学 | 318篇 |
皮肤病学 | 27篇 |
神经病学 | 131篇 |
特种医学 | 103篇 |
外科学 | 270篇 |
综合类 | 20篇 |
一般理论 | 2篇 |
预防医学 | 191篇 |
眼科学 | 24篇 |
药学 | 155篇 |
肿瘤学 | 154篇 |
出版年
2021年 | 34篇 |
2020年 | 15篇 |
2019年 | 28篇 |
2018年 | 35篇 |
2017年 | 21篇 |
2016年 | 34篇 |
2015年 | 42篇 |
2014年 | 39篇 |
2013年 | 74篇 |
2012年 | 99篇 |
2011年 | 114篇 |
2010年 | 58篇 |
2009年 | 51篇 |
2008年 | 84篇 |
2007年 | 86篇 |
2006年 | 89篇 |
2005年 | 92篇 |
2004年 | 72篇 |
2003年 | 94篇 |
2002年 | 68篇 |
2001年 | 67篇 |
2000年 | 54篇 |
1999年 | 49篇 |
1998年 | 23篇 |
1997年 | 18篇 |
1996年 | 15篇 |
1995年 | 25篇 |
1993年 | 23篇 |
1992年 | 37篇 |
1991年 | 31篇 |
1990年 | 33篇 |
1989年 | 22篇 |
1988年 | 32篇 |
1987年 | 30篇 |
1986年 | 31篇 |
1985年 | 31篇 |
1984年 | 22篇 |
1983年 | 18篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1979年 | 13篇 |
1978年 | 13篇 |
1977年 | 12篇 |
1976年 | 13篇 |
1975年 | 14篇 |
1974年 | 11篇 |
1973年 | 11篇 |
1971年 | 14篇 |
1967年 | 10篇 |
1966年 | 10篇 |
排序方式: 共有2017条查询结果,搜索用时 31 毫秒
1.
Cynthia J. Hines Thomas J. Lentz Lauralynn McKernan Pranav Rane Christine Whittaker 《Journal of occupational and environmental hygiene》2019,16(2):120-128
Bisphenol A is a commercially important chemical used to make polycarbonate plastic, epoxy resins, and other specialty products. Despite an extensive body of in vitro, animal and human observational studies on the effects of exposure to bisphenol A, no authoritative bodies in the U.S. have adopted or recommended occupational exposure limits for bisphenol A. In 2017, the National Institute for Occupational Safety and Health published a Draft process for assigning health-protective occupational exposure bands, i.e., an airborne concentration range, to chemicals lacking an occupational exposure limit. Occupational exposure banding is a systematic process that uses both quantitative and qualitative toxicity information on selected health effect endpoints to assign an occupational exposure band for a chemical. The Draft process proposes three methodological tiers of increasing complexity for assigning an occupational exposure band. We applied Tier 1 (based on the Globally Harmonized System of Classification and Labelling) and Tier 2 (based on authoritative sources/reviews) to assign an occupational exposure band to bisphenol A. Under both Tier 1 and 2, the occupational exposure band for bisphenol A was “E” (<0.01?mg/m3), an assignment based on eye damage. “E” is the lowest exposure concentration range, reserved for chemicals with high potential toxicity. If eye damage was excluded in assigning an air concentration exposure range, then bisphenol A would band as “D” (>0.01 to 0.1?mg/m3) under Tier 1 (based on reproductive toxicity and respiratory/skin sensitization) and under Tier 2 (based on specific target organ toxicity-repeated exposure). In summary, Tiers 1 and 2 gave the same occupational exposure band for bisphenol A when eye damage was included (“E”) or excluded (“D”) as an endpoint. 相似文献
2.
Esther M. John Amanda I. Phipps Lisa M. Hines Jocelyn Koo Sue A. Ingles Kathy B. Baumgartner Martha L. Slattery Anna H. Wu 《International journal of cancer. Journal international du cancer》2020,147(7):1808-1822
We pooled multiethnic data from four population-based studies and examined associations of menstrual and reproductive characteristics with breast cancer (BC) risk by tumor hormone receptor (HR) status [defined by estrogen receptor (ER) and progesterone receptor (PR)]. We estimated odds ratios and 95% confidence intervals using multivariable logistic regression, stratified by age (<50, ≥50 years) and ethnicity, for 5,186 HR+ (ER+ or PR+) cases, 1,365 HR− (ER− and PR−) cases and 7,480 controls. For HR+ BC, later menarche and earlier menopause were associated with lower risk in non-Hispanic whites (NHWs) and Hispanics, and higher parity and longer breast-feeding were associated with lower risk in Hispanics and Asian Americans, and suggestively in NHWs. Positive associations with later first full-term pregnancy (FTP), longer interval between menarche and first FTP and shorter time since last FTP were limited to younger Hispanics and Asian Americans. Except for nulliparity, reproductive characteristics were not associated with risk in African Americans. For HR− BC, lower risk was associated with later menarche, except in African Americans and older Asian Americans and with longer breast-feeding in Hispanics and Asian Americans only. In younger African Americans, HR− BC risk associated with higher parity (≥3 vs. 1 FTP) was increased fourfold in women who never breast-fed, but not in those with a breast-feeding history, suggesting that breast-feeding may mitigate the adverse effect of higher parity in younger African American women. Further work needs to evaluate why menstrual and reproductive risk factors vary in importance according to age and ethnicity. 相似文献
3.
4.
5.
6.
7.
The association between speed of transition from initiation to subsequent use of cannabis and later problematic cannabis use,abuse and dependence 下载免费PDF全文
8.
9.
10.
Anika L. Hines Debra Roter Bri K. Ghods Dinoso Kathryn A. Carson Gail L. Daumit Lisa A. Cooper 《Patient education and counseling》2018,101(2):233-240