全文获取类型
收费全文 | 1355464篇 |
免费 | 96277篇 |
国内免费 | 2906篇 |
专业分类
耳鼻咽喉 | 19913篇 |
儿科学 | 41472篇 |
妇产科学 | 39086篇 |
基础医学 | 190931篇 |
口腔科学 | 39880篇 |
临床医学 | 113649篇 |
内科学 | 265502篇 |
皮肤病学 | 30450篇 |
神经病学 | 108119篇 |
特种医学 | 55579篇 |
外国民族医学 | 435篇 |
外科学 | 212210篇 |
综合类 | 31136篇 |
现状与发展 | 6篇 |
一般理论 | 436篇 |
预防医学 | 93341篇 |
眼科学 | 31693篇 |
药学 | 101392篇 |
3篇 | |
中国医学 | 2988篇 |
肿瘤学 | 76426篇 |
出版年
2018年 | 13217篇 |
2016年 | 11606篇 |
2015年 | 12353篇 |
2014年 | 16856篇 |
2013年 | 25342篇 |
2012年 | 34419篇 |
2011年 | 35559篇 |
2010年 | 20783篇 |
2009年 | 20423篇 |
2008年 | 33686篇 |
2007年 | 36778篇 |
2006年 | 37436篇 |
2005年 | 40353篇 |
2004年 | 41107篇 |
2003年 | 37877篇 |
2002年 | 33871篇 |
2001年 | 63654篇 |
2000年 | 65328篇 |
1999年 | 55389篇 |
1998年 | 14654篇 |
1997年 | 13458篇 |
1996年 | 12937篇 |
1995年 | 12221篇 |
1994年 | 11468篇 |
1992年 | 42762篇 |
1991年 | 41282篇 |
1990年 | 40553篇 |
1989年 | 39550篇 |
1988年 | 36964篇 |
1987年 | 36409篇 |
1986年 | 34899篇 |
1985年 | 33101篇 |
1984年 | 24822篇 |
1983年 | 21052篇 |
1982年 | 12664篇 |
1981年 | 11568篇 |
1979年 | 23923篇 |
1978年 | 17068篇 |
1977年 | 14834篇 |
1976年 | 13386篇 |
1975年 | 15267篇 |
1974年 | 18080篇 |
1973年 | 17560篇 |
1972年 | 16810篇 |
1971年 | 15717篇 |
1970年 | 14914篇 |
1969年 | 14346篇 |
1968年 | 13460篇 |
1967年 | 12015篇 |
1966年 | 11258篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
Toneva Diana H. Nikolova Silviya Y. Tasheva-Terzieva Elena D. Zlatareva Dora K. Lazarov Nikolai E. 《International journal of legal medicine》2022,136(6):1851-1863
International Journal of Legal Medicine - Sex identification is a primary step in forensic analysis of skeletal remains. The accuracy of sex estimation methods greatly depends on the sexual... 相似文献
182.
183.
184.
185.
186.
S. Xing X. Zhang J. H. Liu X. Huang P. Zhou 《Clinical and experimental immunology》2019,195(1):121-131
Recent experimental strategies to reduce graft-versus-host disease (GVHD) have focused largely on modifying innate immunity. Toll-like receptor (TLR)-driven myeloid differentiation primary response 88 (MyD88)-dependent signalling pathways that initiate adaptive immune function are also critical for the pathogenesis of GVHD. This study aimed to delineate the role of host MyD88 in the development of acute GVHD following fully major histocompatibility complex-mismatched allogeneic bone marrow transplantation (BMT). When myeloablated BALB/c MyD88 knock-out recipients were transplanted with C57BL/6 (B6) donor cells, they developed significantly more severe GVHD than wild-type (WT) BALB/c hosts. The increased morbidity and mortality in MyD88–/– mice correlated with increased serum levels of lipopolysaccharide and elevated inflammatory cytokines in GVHD target organs. Additionally, MyD88 deficiency in BMT recipients led to increased donor T cell expansion and more donor CD11c+ cell intestinal infiltration with apoptotic cells but reduced proliferation of intestinal epithelial cells compared with that in WT BMT recipients. Decreased expression of tight junction mRNA in epithelial cells of MyD88–/– mice suggested that MyD88 contributes to intestinal integrity. Cox-2 expression in the GVHD-targeted organs of WT mice is increased upon GVHD induction, but this enhanced expression was obviously inhibited by MyD88 deficiency. The present findings demonstrate an unexpected role for host MyD88 in preventing GVHD after allogeneic BMT. 相似文献
187.
Darren R. Feldman MD Yasser Ged MBBS Chung-Han Lee PhD Andrea Knezevic MS Ana M. Molina MD Ying-Bei Chen PhD Joshua Chaim DO Devyn T. Coskey MS Samuel Murray MS Satish K. Tickoo MD Victor E. Reuter MD Sujata Patil PhD Han Xiao MD Jahan Aghalar MD Arlyn J. Apollo MD Maria I. Carlo MD Robert J. Motzer MD Martin H. Voss MD 《Cancer》2020,126(24):5247-5255
188.
189.
Solid-state reactions between sodium hydride and sodium hydroxide are unusual among hydride-hydroxide systems since hydrogen can be stored reversibly. In order to understand the relationship between hydrogen uptake/release properties and phase/structure evolution, the dehydrogenation and hydrogenation behavior of the Na-O-H system has been investigated in detail both ex- and in-situ. Simultaneous thermogravimetric-differential thermal analysis coupled to mass spectrometry (TG-DTA-MS) experiments of NaH-NaOH composites reveal two principal features: Firstly, an H2 desorption event occurring between 240 and 380 °C and secondly an additional endothermic process at around 170 °C with no associated weight change. In-situ high-resolution synchrotron powder X-ray diffraction showed that NaOH appears to form a solid solution with NaH yielding a new cubic complex hydride phase below 200 °C. The Na-H-OH phase persists up to the maximum temperature of the in-situ diffraction experiment shortly before dehydrogenation occurs. The present work suggests that not only is the inter-phase synergic interaction of protic hydrogen (in NaOH) and hydridic hydrogen (in NaH) important in the dehydrogenation mechanism, but that also an intra-phase Hδ+… Hδ– interaction may be a crucial step in the desorption process. 相似文献
190.
Ming-Yeh Yang Ching-Yuan Huang Tina H.T. Chiu Kai-Chih Chang Ming-Nan Lin Liang-Yü Chen Anren Hu 《Yao wu shi pin fen xi = Journal of food and drug analysis.》2019,27(2):494-501
Vitamin D is responsible for multiple metabolic functions in humans. Rickets are the most common disease caused by vitamin D deficiency. It is caused by poor calcium intake resulting in poor serum-ionized calcium. The purpose of this study is to develop a rapid, sensitive, and feasible method to determine the 25-hydroxy-vitamin D3 (25(OH)D3) levels in blood samples for clinical assessment. In this study, gas chromatography coupled mass spectrometry with trimethylsilyl derivatization (TMS-GC-MS) is the most suitable protocol for quantitative analyses of 25(OH)D3. Performance of method was evaluated and compared with liquid chromatography and immunoassay. Method validation has been carried out with plasma specimens. The limit of quantitation of TMS-GC-MS method is 1.5 ppb with good linear correlation. Furthermore, the dietary intake and nutritional status of vegetarian and non-vegetarians in Taiwan were assessed by our validated method. As a result, this vitamin D nutrition survey demonstrates that most Taiwanese people have insufficient vitamin D. Due to dietary habits; the male vegans may have the highest risk of vitamin D deficiency. 相似文献