全文获取类型
收费全文 | 46111篇 |
免费 | 4838篇 |
国内免费 | 123篇 |
专业分类
耳鼻咽喉 | 438篇 |
儿科学 | 1206篇 |
妇产科学 | 1096篇 |
基础医学 | 6906篇 |
口腔科学 | 1060篇 |
临床医学 | 5685篇 |
内科学 | 8446篇 |
皮肤病学 | 546篇 |
神经病学 | 4453篇 |
特种医学 | 1841篇 |
外国民族医学 | 57篇 |
外科学 | 5931篇 |
综合类 | 995篇 |
一般理论 | 43篇 |
预防医学 | 5158篇 |
眼科学 | 1129篇 |
药学 | 3445篇 |
1篇 | |
中国医学 | 24篇 |
肿瘤学 | 2612篇 |
出版年
2021年 | 657篇 |
2020年 | 408篇 |
2019年 | 645篇 |
2018年 | 718篇 |
2017年 | 552篇 |
2016年 | 605篇 |
2015年 | 644篇 |
2014年 | 965篇 |
2013年 | 1518篇 |
2012年 | 2029篇 |
2011年 | 2068篇 |
2010年 | 1235篇 |
2009年 | 1072篇 |
2008年 | 1969篇 |
2007年 | 1976篇 |
2006年 | 1999篇 |
2005年 | 1914篇 |
2004年 | 1948篇 |
2003年 | 1719篇 |
2002年 | 1692篇 |
2001年 | 1487篇 |
2000年 | 1628篇 |
1999年 | 1367篇 |
1998年 | 596篇 |
1997年 | 515篇 |
1996年 | 469篇 |
1995年 | 474篇 |
1994年 | 438篇 |
1993年 | 400篇 |
1992年 | 1072篇 |
1991年 | 1113篇 |
1990年 | 1021篇 |
1989年 | 1008篇 |
1988年 | 1014篇 |
1987年 | 882篇 |
1986年 | 872篇 |
1985年 | 844篇 |
1984年 | 701篇 |
1983年 | 584篇 |
1982年 | 382篇 |
1981年 | 360篇 |
1980年 | 350篇 |
1979年 | 661篇 |
1978年 | 516篇 |
1977年 | 438篇 |
1976年 | 414篇 |
1975年 | 385篇 |
1974年 | 438篇 |
1973年 | 435篇 |
1972年 | 377篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
942.
RESOLVE: a randomized,controlled, blinded study of bioabsorbable steroid‐eluting sinus implants for in‐office treatment of recurrent sinonasal polyposis 下载免费PDF全文
Joseph K. Han MD Keith D. Forwith PhD MD Timothy L. Smith MD MPH Robert C. Kern MD William J. Brown MD Steven K. Miller MD Randall A. Ow MD David M. Poetker MD Boris Karanfilov MD Keith E. Matheny MD James Stambaugh BS Anna K. Gawlicka PhD MBA 《International forum of allergy & rhinology》2014,4(11):861-870
943.
Sreekanth Vemulapalli Jamy Ard George L. Bakris Deepak L. Bhatt Alan S. Brown William C. Cushman Keith C. Ferdinand John M. Flack Jerome L. Fleg Barry T. Katzen John B. Kostis Suzanne Oparil Chet B. Patel Carl J. Pepine Ileana L. Piña Krishna J. Rocha-Singh Raymond R. Townsend Eric D. Peterson Robert M. Califf Manesh R. Patel 《American heart journal》2014
944.
945.
946.
947.
948.
949.
950.
Felicity Payne Koini Lim Amandine Girousse Rebecca J. Brown Nora Kory Ann Robbins Yali Xue Alison Sleigh Elaine Cochran Claire Adams Arundhati Dev Borman David Russel-Jones Phillip Gorden Robert K. Semple Vladimir Saudek Stephen O’Rahilly Tobias C. Walther Inês Barroso David B. Savage 《Proceedings of the National Academy of Sciences of the United States of America》2014,111(24):8901-8906
Phosphatidylcholine (PC) is the major glycerophospholipid in eukaryotic cells and is an essential component in all cellular membranes. The biochemistry of de novo PC synthesis by the Kennedy pathway is well established, but less is known about the physiological functions of PC. We identified two unrelated patients with defects in the Kennedy pathway due to biallellic loss-of-function mutations in phosphate cytidylyltransferase 1 alpha (PCYT1A), the rate-limiting enzyme in this pathway. The mutations lead to a marked reduction in PCYT1A expression and PC synthesis. The phenotypic consequences include some features, such as severe fatty liver and low HDL cholesterol levels, that are predicted by the results of previously reported liver-specific deletion of murine Pcyt1a. Both patients also had lipodystrophy, severe insulin resistance, and diabetes, providing evidence for an additional and essential role for PCYT1A-generated PC in the normal function of white adipose tissue and insulin action.All living cells are surrounded by a lipid membrane. Eukaryotic cells also contain several internal membrane-bound organelles, which enable them to compartmentalize related biological functions and thereby to enhance the efficiency of these processes. Phospholipids are the predominant component of these membranes. Their hydrophilic head groups interact with the cytosol, whereas their hydrophobic side chains are either buried within the hydrophobic interior of a typical membrane bilayer or interact with the hydrophobic neutral lipid core of lipoproteins and lipid droplets (LDs). Phospholipids are generally defined by their organic head group with phosphatidylcholine (PC) constituting over 50% of all membrane phospholipids. PC was first isolated in the 19th century and the major enzymatic pathway involved in its synthesis was revealed by Kennedy and Weiss (1) in the 1950s. Cells synthesize PC in three consecutive steps (Fig. 1A): choline kinase phosphorylates choline before choline phosphate cytidylyltransferase 1 α (encoded by the PCYT1A gene) generates the high-energy donor CDP-choline in the rate-limiting step of the pathway. In the last step, DAG:CDP-choline cholinephosphotransferase (CPT) uses CDP-choline and diacylglycerol (DAG) to form PC (2, 3).Open in a separate windowFig. 1.Cosegregation of biallelic PCYT1A mutations with fatty liver, low HDL cholesterol levels, lipodystrophy, insulin-resistant diabetes, and short stature. (A) Schematic illustration of the Kennedy PC synthesis pathway. CK, choline kinase; CPT, CDP-choline:1,2-diacylglycerol cholinephosphotransferase; PCYT1A, choline-phosphate cytidylyltransferase A, CTP:phosphocholine-cytidylyltransferase. (B) Family pedigrees of both probands demonstrating that only compound heterozygous carriers of PCYT1A mutations manifest fatty liver (red), low HDL cholesterol (blue), lipodystrophy (yellow), and insulin resistance/type 2 diabetes (T2DM) (green). PCYT1A mutation status, height (Ht.), and body mass index (BMI) are indicated below each individual’s symbol. ND, not determined; WT, wild type. (C) The location of PCYT1A mutations E280del, V142M, and 333fs in relation to known functional domains of PCYT1A. Domain M, membrane binding domain; domain P, phosphorylated region. (D) Conservation around the V142(red*) and E280(red*) mutation sites. Sequence alignment of representative metazoan sequences in the region surrounding the mutated residues. Hydrophobic (blue) and polar (green) residues interacting with V142 are highlighted. Only residues different from the human sequence are shown. Sequence IDs: human (Homo sapiens) , zebrafish (Danio rerio) F1QEN6, sea squirt (Ciona intestinalis) P49585, sea urchin (Strongylocentrotus purpuratus) H3I3V9, water flee (Daphnia pulex) E9G1P5, Drosophila (D. melanogaster) Q9W0D9, Caenorhabditis (C. elegans) XP_002130773.1, Trichoplax (T. adherens) B3RI62. (E and F) Structure of the catalytic domain of PCYT1A highlighting the role of V142M in the core packing. The two chains in the dimer are shown in yellow and gray; the residues and the secondary structure units are highlighted in color in the yellow monomer A: loop L3 with V142, red; α-helix, green; and the interacting β-sheet, blue. The residues packing with V142 are shown in ball-and-stick and space-filling representations, the dimer stabilizing R140 is shown in ball-and-stick colored according to the atom type. E is a global view, and F is a zoomed-in view of the catalytic core.Membrane phospholipids are a defining feature of advanced life-forms so it is perhaps not surprising that the pathways involved in their synthesis are ancient, and mutations affecting them are rarely tolerated in evolution. Here, we describe the identification and characterization of pathogenic human loss-of-function mutations affecting the eponymous Kennedy pathway. P49583相似文献