全文获取类型
收费全文 | 1461517篇 |
免费 | 115308篇 |
国内免费 | 13140篇 |
专业分类
耳鼻咽喉 | 17781篇 |
儿科学 | 45378篇 |
妇产科学 | 37725篇 |
基础医学 | 209666篇 |
口腔科学 | 38411篇 |
临床医学 | 147724篇 |
内科学 | 272902篇 |
皮肤病学 | 27942篇 |
神经病学 | 116335篇 |
特种医学 | 52641篇 |
外国民族医学 | 410篇 |
外科学 | 193874篇 |
综合类 | 57653篇 |
现状与发展 | 41篇 |
一般理论 | 468篇 |
预防医学 | 126281篇 |
眼科学 | 32534篇 |
药学 | 113842篇 |
238篇 | |
中国医学 | 13833篇 |
肿瘤学 | 84286篇 |
出版年
2021年 | 17269篇 |
2020年 | 12086篇 |
2019年 | 15513篇 |
2018年 | 20217篇 |
2017年 | 16714篇 |
2016年 | 16935篇 |
2015年 | 21389篇 |
2014年 | 28396篇 |
2013年 | 39853篇 |
2012年 | 55834篇 |
2011年 | 59173篇 |
2010年 | 36560篇 |
2009年 | 32790篇 |
2008年 | 51332篇 |
2007年 | 53304篇 |
2006年 | 52448篇 |
2005年 | 50068篇 |
2004年 | 45866篇 |
2003年 | 43479篇 |
2002年 | 41555篇 |
2001年 | 63343篇 |
2000年 | 64591篇 |
1999年 | 53842篇 |
1998年 | 15512篇 |
1997年 | 14242篇 |
1996年 | 13841篇 |
1995年 | 13080篇 |
1994年 | 12199篇 |
1993年 | 11254篇 |
1992年 | 41850篇 |
1991年 | 41035篇 |
1990年 | 39693篇 |
1989年 | 37533篇 |
1988年 | 34763篇 |
1987年 | 33847篇 |
1986年 | 32247篇 |
1985年 | 30713篇 |
1984年 | 23071篇 |
1983年 | 19623篇 |
1982年 | 11763篇 |
1979年 | 20815篇 |
1978年 | 14815篇 |
1977年 | 12065篇 |
1976年 | 11877篇 |
1975年 | 12114篇 |
1974年 | 14801篇 |
1973年 | 14476篇 |
1972年 | 13356篇 |
1971年 | 12418篇 |
1970年 | 11485篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
目的 通过观察早产儿不同胎龄Toll样受体9(TLR9)的表达,探讨早产儿免疫功能低下的机制。方法 采集2010年7月至2014年6月在上海市嘉定区妇幼保健院产科出生的活产新生儿的脐血229份,按胎龄分为4组,28~31周组,31~34周组,34~37周组,≥37周组,采用流式细胞术和实时荧光定量PCR方法,分别检测其TLR9的蛋白和mRNA表达情况,了解其与胎龄之间的关系,并分析mRNA和蛋白表达间的相关性。结果 TLR9阳性细胞率在28~31周组,31~34周组,34~37周组,≥37周组分别为(15.93±6.23)%,(11.63±6.70)%,(13.66±6.88)%,(20.51±12.06)%;其在胎龄28~31周较高,至31~34周逐渐下降至最低,两组差异有统计学意义(P<0.05);34~37周后TLR9阳性细胞率表达逐渐升高,至≥37周达最高,两胎龄组比较,差异具有统计学意义(P<0.05)。31~37周间新生儿脐血TLR9阳性细胞率与胎龄呈正相关(r=0.273,P=0.006)。TLR9 mRNA表达在28~31周组,31~34周组,34~37周组,≥37周组分别为(4.95±3.44)%,(8.89±8.49)%,(13.91±10.92)%,(7.19±7.11)%;其在28~36周逐渐升高,与胎龄呈正相关(r=0.355,P< 0.001)。≥37周TLR9 mRNA表达量下降,该值虽高于28~31周,但差异无统计学意义(P>0.05)。相关性分析表明,同胎龄时期同样本新生儿的TLR9 mRNA和TLR9阳性细胞率之间存在负相关(r=-0.227,P=0.011)。结论 TLR9阳性细胞率和TLR9 mRNA表达在不同胎龄组新生儿间有差异,TLR9阳性细胞率表达在31~37周间随着胎龄的增加而增加,TLR9 mRNA在28~36周间随着胎龄的增加而增加。 相似文献
123.
Dana Franzen-Klein Mark Jankowski Charlotte L. Roy Hoa Nguyen-Phuc Da Chen Lorin Neuman-Lee 《Journal of toxicology and environmental health. Part A》2020,83(2):45-65
ABSTRACTDomestic 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
124.
125.
126.
127.
128.
129.
Eric S. Zhou Larissa Nekhlyudov Sharon L. Bober 《Translational andrology and urology》2015,4(2):218-231
There is a large and growing population of long-term cancer survivors. Primary care physicians (PCPs) are playing an increasingly greater role in the care of these patients across the continuum of cancer survivorship. In this role, PCPs are faced with the responsibility of managing a range of medical and psychosocial late effects of cancer treatment. In particular, the sexual side effects of treatment which are common and have significant impact on quality of life for the cancer survivor, often go unaddressed. This is an area of clinical care and research that has received increasing attention, highlighted by the presentation of this special issue on Cancer and Sexual Health. The aims of this review are 3-fold. First, we seek to overview common presentations of sexual dysfunction related to major cancer diagnoses in order to give the PCP a sense of the medical issues that the survivor may present with. Barriers to communication about sexual health issues between patient/PCPs in order are also described in order to emphasize the importance of PCPs initiating this important conversation. Next, we provide strategies and resources to help guide the PCP in the management of sexual dysfunction in cancer survivors. Finally, we discuss case examples of survivorship sexual health issues and highlight the role that a PCP can play in each of these case examples. 相似文献
130.