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   244019篇
  免费   37719篇
  国内免费   2728篇
耳鼻咽喉   6103篇
儿科学   7715篇
妇产科学   4087篇
基础医学   15287篇
口腔科学   3180篇
临床医学   36442篇
内科学   65713篇
皮肤病学   8608篇
神经病学   24242篇
特种医学   10018篇
外国民族医学   3篇
外科学   55895篇
综合类   1306篇
现状与发展   72篇
一般理论   131篇
预防医学   14906篇
眼科学   5319篇
药学   7307篇
中国医学   114篇
肿瘤学   18018篇
  2024年   543篇
  2023年   5145篇
  2022年   2023篇
  2021年   5026篇
  2020年   7158篇
  2019年   4136篇
  2018年   9681篇
  2017年   8893篇
  2016年   10093篇
  2015年   10399篇
  2014年   18501篇
  2013年   19834篇
  2012年   12749篇
  2011年   13144篇
  2010年   14559篇
  2009年   17900篇
  2008年   12620篇
  2007年   11223篇
  2006年   13393篇
  2005年   10420篇
  2004年   9564篇
  2003年   7888篇
  2002年   7649篇
  2001年   4508篇
  2000年   3458篇
  1999年   3986篇
  1998年   4724篇
  1997年   4256篇
  1996年   3997篇
  1995年   3791篇
  1994年   2471篇
  1993年   2098篇
  1992年   1767篇
  1991年   1751篇
  1990年   1349篇
  1989年   1434篇
  1988年   1261篇
  1987年   1115篇
  1986年   1098篇
  1985年   978篇
  1984年   830篇
  1983年   764篇
  1982年   838篇
  1981年   674篇
  1980年   575篇
  1979年   396篇
  1978年   453篇
  1977年   498篇
  1975年   341篇
  1972年   346篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
ABSTRACT

Domestic chickens (Gallus gallus domesticus) were exposed to imidacloprid by gavage once daily for 7 consecutive days at 0, 0.03, 0.34, 3.42, 10.25, and 15.5 mg/kg/day (n = 20 per group; 5 6-week-old males, 5 6-week-old females, 5 9-week-old males, and 5 9-week-old females). The severity and duration of neurobehavioral abnormalities were recorded. Components of the innate and adaptive immune system were assessed with 7 standard functional assays. Temporary neurobehavioral abnormalities were observed in a dose-dependent manner, including muscle tremors, ataxia, and depressed mentation. Based upon mean clinical severity scores, the no observed adverse effect level (NOAEL) was 3.42 mg/kg/day, and the lowest observed adverse effect level (LOAEL) was 10.25 mg/kg/day. The effective dose value for the presence of any neurobehavioral abnormalities in 50% of the test group (ED50) was 4.62 ± 0.98 mg/kg/day. The ED50 for an adjusted score that included both severity and duration of neurobehavioral abnormalities was 11.24 ± 9.33 mg/kg/day. These ED50 values are equivalent to a 1 kg bird ingesting 29 or 70 imidacloprid treated soybean seeds respectively. Immunotoxicity was not documented, possible causes include the assays were insensitive, relevant immune functions were not examined, or imidacloprid is not immunotoxic at this dosing schedule in this species. Neurobehavioral abnormalities were a more sensitive indicator of the sublethal effects of imidacloprid than immunotoxicity.  相似文献   
52.
53.
54.
55.
56.
57.
Multimodality primary therapies for breast cancer combined with earlier detection have led to a sharp decline in the death rate from breast cancer in the UK over the last 40 years in the face of a rising incidence. The latest UK statistics from Cancer Research UK report 55,122 new cases of breast cancer in 2015 with 11,563 deaths from breast cancer recorded in 2016. Crudely, this equates to a cure rate of around 80% for all comers and demonstrates a clear improvement in outcome with 50,285 new cases in 2011 and 11,716 deaths in 2012. Despite this good news, there are still significant numbers of women (and men) who suffer from either a local recurrence or metastatic disease following apparently successful treatment for early breast cancer (Stage I to III). Only a minority of individuals, 6.6% with the stage recorded at diagnosis, present with stage IV disease. This review considers the treatment options available to individuals with locally recurrent and advanced breast cancer (ABC).  相似文献   
58.
59.
60.
PurposeOur purpose was to determine the effect of chemoradiotherapy (CRT) on patient-reported quality of life (QOL) for patients with intact pancreas cancer.Methods and MaterialsWe reviewed a prospective QOL registry for patients with intact, clinically localized pancreatic ductal adenocarcinoma treated with CRT between June 2015 and November 2018. QOL was assessed pre-CRT (immediately before CRT, after neoadjuvant chemotherapy) and at the completion of CRT with the Functional Assessment of Cancer Therapy-Hepatobiliary (FACT-Hep) and its component parts: FACT-General (FACT-G) and hepatobiliary cancer subscore (HCS). A minimally important difference from pre-CRT was defined as ≥ 6, 5, and 8 points for FACT-G, HCS, and FACT-Hep, respectively.ResultsOf 157 patients who underwent CRT, 100 completed both pre- and post-CRT surveys and were included in the primary analysis. Median age at diagnosis was 65 years (range, 23-90). National Comprehensive Cancer Network resectability status was resectable (3%), borderline resectable (40%), or locally advanced (57%). Folinic acid, 5-fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX) (75%) or gemcitabine and nab-paclitaxel (42%) were given for a median of 6 cycles (range, 0-42) before CRT. Radiation therapy techniques included 3-dimensional conformal (22%), intensity modulated photon (55%), and intensity modulated proton (23%) radiation therapy to a median dose of 50 Gy (range, 36-62.5). Concurrent chemotherapy was most commonly capecitabine (82%). Sixty-three patients (63%) had surgery after CRT. The mean decline in FACT-G, HCS subscale, and FACT-Hep from pre- to post-CRT was 3.5 (standard deviation [SD], 13.7), 1.7 (SD 7.8), and 5.2 (SD 19.4), respectively. Each of these changes were statistically significant, but did not meet the minimally important difference threshold. Pancreatic head tumor location was associated with decline in FACT-Hep. Nausea was the toxicity with the greatest increase from pre- to post-CRT by both physician-assessment and patient-reported QOL.ConclusionsFor patients with intact pancreatic adenocarcinoma, modern CRT is well tolerated with minimal decline in QOL during treatment.  相似文献   
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