全文获取类型
收费全文 | 107257篇 |
免费 | 8852篇 |
国内免费 | 5969篇 |
专业分类
耳鼻咽喉 | 966篇 |
儿科学 | 1703篇 |
妇产科学 | 965篇 |
基础医学 | 10834篇 |
口腔科学 | 1863篇 |
临床医学 | 13552篇 |
内科学 | 13999篇 |
皮肤病学 | 1619篇 |
神经病学 | 4629篇 |
特种医学 | 4108篇 |
外国民族医学 | 26篇 |
外科学 | 9321篇 |
综合类 | 21372篇 |
现状与发展 | 23篇 |
一般理论 | 7篇 |
预防医学 | 9949篇 |
眼科学 | 2359篇 |
药学 | 11546篇 |
83篇 | |
中国医学 | 6253篇 |
肿瘤学 | 6901篇 |
出版年
2024年 | 217篇 |
2023年 | 953篇 |
2022年 | 2495篇 |
2021年 | 3457篇 |
2020年 | 2716篇 |
2019年 | 2325篇 |
2018年 | 2444篇 |
2017年 | 2618篇 |
2016年 | 2690篇 |
2015年 | 4248篇 |
2014年 | 5554篇 |
2013年 | 6071篇 |
2012年 | 8840篇 |
2011年 | 9370篇 |
2010年 | 7357篇 |
2009年 | 6398篇 |
2008年 | 7413篇 |
2007年 | 7368篇 |
2006年 | 6828篇 |
2005年 | 6088篇 |
2004年 | 4803篇 |
2003年 | 4939篇 |
2002年 | 3891篇 |
2001年 | 3101篇 |
2000年 | 2413篇 |
1999年 | 1603篇 |
1998年 | 877篇 |
1997年 | 934篇 |
1996年 | 623篇 |
1995年 | 541篇 |
1994年 | 457篇 |
1993年 | 308篇 |
1992年 | 345篇 |
1991年 | 288篇 |
1990年 | 254篇 |
1989年 | 207篇 |
1988年 | 175篇 |
1987年 | 158篇 |
1986年 | 117篇 |
1985年 | 120篇 |
1984年 | 70篇 |
1983年 | 53篇 |
1982年 | 38篇 |
1981年 | 30篇 |
1980年 | 20篇 |
1979年 | 37篇 |
1978年 | 34篇 |
1976年 | 23篇 |
1973年 | 27篇 |
1970年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Almeida G. L.; Hong D. A.; Corcos D.; Gottlieb G. L. 《Journal of neurophysiology》1995,74(4):1374-1381
102.
Ehrlich S Breeze JL Hesdorffer DC Noam GG Hong X Alban RL Davis SE Renshaw PF 《Journal of affective disorders》2005,86(2-3):281-287
INTRODUCTION: Researchers and clinicians have increasingly recognized that biological markers may help identify patients who are at risk for suicide. The objective of this retrospective, cross-sectional study was to compare the prevalence and location of white matter hyperintensities (WMH) in young inpatients with major depressive disorder (MDD) with and without histories of suicide attempts. METHODS: T2-weighted magnetic resonance images (MRI) of 102 young psychiatric inpatients with MDD were rated for the presence of WMH. Medical charts were reviewed to ascertain history of suicide attempt, demographic and clinical variables. Fisher's Exact Tests and logistic regression modeling were used to test the association between WMH and suicidality. RESULTS: Bivariate analysis showed that the prevalence of periventricular WMH was significantly higher in subjects with past suicide attempts (Fisher's Exact Test, p=0.02). Logistic regression analyses controlling for age, sex, and several clinical risk factors supported this finding (odds ratio=5.7; 95% confidence interval: 1.6, 21.2). LIMITATIONS: Due to the retrospective, cross-sectional design of our study, we are unable to determine if the WMH preceded or followed past suicide attempts. The generalizability of our findings is limited since this group of inpatients is more severely ill than the general psychiatric population. CONCLUSIONS: The increased prevalence of periventricular WMH in young adults with MDD and a history of suicide attempt, compared to similarly depressed adults without such a history, is consistent with our findings in children and youth, and suggests there might be neurobiological in addition to psychosocial risk factors for suicide. 相似文献
103.
D S Longnecker O S Pettengill B H Davis B K Schaeffer J Zurlo H L Hong E T Kuhlmann 《The American journal of pathology》1991,138(2):333-340
Nodules of acinar cells with increased proliferative potential develop in the pancreas of carcinogen-treated rats and in untreated aged rats. Large nodules are classed as adenomas. Phenotypic and genotypic characteristics of nodule cells were compared with normal pancreas and transplantable acinar cell carcinomas by several methods. Nuclei of acinar cells from normal pancreas, adenomas, and three carcinomas in situ had normal diploid DNA content as determined by flow cytometry. One of two primary carcinomas had a hypodiploid DNA content. Two of three transplantable carcinomas were aneuploid with a DNA content in the tetraploid range. Explants from nodules and adenomas failed to grow in soft agar, whereas several carcinomas were positive in this assay. A primary carcinoma was serially transplanted, but transplantation of nodules or adenomas failed. Transfection of DNA from carcinomas in situ yielded a higher frequency of NIH 3T3 transformants than DNA from adenomas. DNAs from the transformants did not contain ras sequences. These studies indicate that cells from nodules and adenomas have low growth potential and lack critical phenotypic and genotypic characteristics of transformed malignant cells that were present in some primary and transplanted carcinomas. 相似文献
104.
105.
领导干部心理健康量表的初步编制 总被引:1,自引:0,他引:1
目的编制一套适用于领导干部群体的心理健康量表。方法通过文献研究、个案分析、问卷调查等,确立测验结构并编制成预测量表,通过对127位被试施测结果进行条目分析等形成正式量表,并进行因子分析等考察量表的信度和效度。结果编制成一个含3个量表:心理症状量表、自我概念量表、外界适应量表,共计93个项目的测评系统。项目与其所在量表的题总相关系数在0.445~0.855之间(P<0.001),各条目决断值(CR值)均具有显著性;对自我概念量表和外界适应量表探索性因素分析分别提取4个和3个公因子,累计解释总变异量分别为54.842%,48.365%,因子载荷在0.427~0.814和0.434~0.796之间;各量表的Cronbach'sα系数分别为0.775,0.860,0.952。结论初步研究显示量表的信效度均达到心理学测量标准,具有较好的信效度。 相似文献
106.
We report on the antileukemia effect of interleukin 2 (IL2) on different immune cells from 22 patients with chronic myeloid leukemia (CML). Bone marrow cells from these patients were first cultured in modified long-term bone marrow culture medium for several days, then separately cultured with lymphokine activated killer cells (LAK), cytokine-induced killer cells (CIK), and dendritic cell cocultured CIK (DC-CIK) for another 1-2 days. They were then detected for presence of the Philadelphia chromosome (Ph) by cytogenetic analysis and fluorescence in situ hybridization (FISH). The percentage of Ph-chromosome-positive cells in the bone marrow mononuclear cells after culturing with CIK and DC-CIK was significantly lower than that after culturing with IL2 or LAK. Our results demonstrate that cytogenetics and FISH are useful techniques for the evaluation of the anti-CML effect of immune cells and that CIK or DC-CIK can be appropriate candidates for adoptive immune cell therapy in vivo or for leukemia cell purging ex vivo. 相似文献
107.
Increased endostatin/collagen XVIII expression correlates with elevated VEGF level and poor prognosis in hepatocellular carcinoma. 总被引:2,自引:0,他引:2
Tsung-Hui Hu Chao-Cheng Huang Chia-Ling Wu Pey-Ru Lin Shang-Yun Liu Jui-Wei Lin Jiin-Haur Chuang Ming Hong Tai 《Modern pathology》2005,18(5):663-672
Liver is the primary source for collagen XVIII, the precursor of angiogenesis inhibitor, endostatin. However, the role of endostatin/collagen XVIII expression during liver carcinogenesis remains elusive. Therefore, we studied its expression in five hepatoma cell lines and 105 hepatocellular carcinoma specimens. The poorly differentiated hepatoma cell lines exhibited increased endostatin/collagen XVIII levels compared with the well-differentiated ones. In hepatoma tissues, endostatin/collagen XVIII expression was detected in various types of liver cells and was significantly stronger in adjacent nontumor tissues than that in tumors (P<0.001). Endostatin/collagen XVIII expression in nontumor tissues correlated with tumor stages (P=0.014) and expression of vascular endothelial growth factor (P=0.007), but not the stages of hepatic fibrosis (P>0.05). Kaplan-Meier analysis showed that patients with higher endostatin/collagen XVIII expression had significantly shorter overall survival (P=0.011) and disease-free survival (P=0.0034). Moreover, endostatin/collagen XVIII level was an independent prognostic factor for tumor recurrence (P=0.034) by multivariate analysis. In conclusion, increased endostatin/collagen XVIII expression correlated with hepatoma progression and predicted poor prognosis for patients with hepatocellular carcinoma. 相似文献
108.
109.
Soo Hyun Kim Yang-Kyoo Han Young Ha Kim Sung Ill Hong 《Macromolecular chemistry and physics.》1992,193(7):1623-1631
L -Lactide was polymerized with stannous 2-ethylhexanoate (stannous octoate) in the presence of pentaerythritol to investigate multifunctional initiation. The prepared oligomers contain starshaped 4-arm molecules when the mole ratio of [lactide]/[pentaerythritol] is above 32. The molecular weight of oligomers coincides with the [lactide]/[pentaerythritol] ratio, indicating that pentaerythritol in conjugation with stannous octoate is an initiator for the “living” polymerization of L-lactide. 相似文献
110.
目的研究路氏乳杆菌(Lactobacillus reuteri,也称罗伊氏乳杆菌)JCM1081菌体表面蛋白对其黏附HT-29细胞的影响。方法将路氏乳杆菌JCM1081菌体进行胰蛋白酶、蛋白酶K处理;用氯化锂和盐酸胍对乳杆菌表面的蛋白进行抽提,进行SDS-PAGE后与黏蛋白受体进行Western blot,并对杂交阳性蛋白进行质谱分析鉴定。结果路氏乳杆菌JCM1081菌体经胰蛋白酶、蛋白酶K处理后,其对HT-29细胞的黏附力显著下降(P<0.01);用氯化锂去除路氏乳杆菌JCM1081菌体外表面的S层蛋白后,路氏乳杆菌JCM1081对HT-29细胞的黏附力无显著变化;Western blot结果显示相对分子质量(Mr)为29×103和14×103的两种菌体表面蛋白与黏蛋白受体杂交中出现了强阳性;质谱分析结果显示29×103蛋白与路氏乳杆菌ATCC55730的h0793蛋白相似性高达71.1%。结论路氏乳杆菌JCM1081菌体表面的蛋白参与了乳杆菌的黏附,其中29×103和14×103的两种胞壁表面蛋白能够特异地识别黏蛋白受体并与之结合,29×103蛋白属ABC转运蛋白家族。 相似文献