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   4738篇
  免费   259篇
  国内免费   31篇
耳鼻咽喉   36篇
儿科学   162篇
妇产科学   55篇
基础医学   479篇
口腔科学   105篇
临床医学   372篇
内科学   1456篇
皮肤病学   47篇
神经病学   377篇
特种医学   122篇
外科学   906篇
综合类   17篇
预防医学   171篇
眼科学   64篇
药学   206篇
中国医学   20篇
肿瘤学   433篇
  2023年   47篇
  2022年   100篇
  2021年   180篇
  2020年   99篇
  2019年   119篇
  2018年   133篇
  2017年   101篇
  2016年   136篇
  2015年   103篇
  2014年   152篇
  2013年   203篇
  2012年   272篇
  2011年   307篇
  2010年   154篇
  2009年   125篇
  2008年   224篇
  2007年   237篇
  2006年   181篇
  2005年   202篇
  2004年   215篇
  2003年   185篇
  2002年   220篇
  2001年   86篇
  2000年   91篇
  1999年   77篇
  1998年   63篇
  1997年   39篇
  1996年   32篇
  1995年   37篇
  1994年   23篇
  1993年   26篇
  1992年   80篇
  1991年   61篇
  1990年   63篇
  1989年   70篇
  1988年   71篇
  1987年   71篇
  1986年   67篇
  1985年   55篇
  1984年   43篇
  1983年   26篇
  1980年   17篇
  1979年   32篇
  1978年   15篇
  1977年   15篇
  1976年   16篇
  1975年   15篇
  1972年   18篇
  1971年   18篇
  1970年   14篇
排序方式: 共有5028条查询结果,搜索用时 31 毫秒
91.
Activated monocytes are present in the arterial walls of hypertensive patients and animals. Monocyte chemoattractant protein-1 (MCP-1), which controls monocyte function through its receptor (CCR2), is implicated in hypertensive inflammatory changes in the arterial wall. The role of CCR2 expression on monocytes in hypertension-induced vascular remodeling, however, has not been addressed. We hypothesized that CCR2 on monocytes is critical in hypertension-induced vascular inflammation and remodeling. Hypertension was induced by infusion of angiotensin II (Ang II) into wild-type mice, CCR2-deficient (CCR2-/-) mice, and bone marrow-transferred mice with a leukocyte-selective CCR2 deficiency (BMT-CCR2-/-). In wild-type mice, Ang II increased CCR2 intensity in circulating monocytes, which was prevented by an Ang II type-1 (AT1) receptor blocker or blunted in AT1 receptor-deficient mice. Enhanced CCR2 intensity on monocytes was observed in hypertensive patients and rats, and was reduced by treatment with the Ang II receptor blocker, supporting the clinical relevance of the observation in mice. In CCR2-/- and BMT-CCR2-/- mice, Ang II-induced vascular inflammation and vascular remodeling (aortic wall thickening and fibrosis) were blunted as compared with control mice. In contrast, Ang II-induced left ventricular hypertrophy developed in CCR2-/- and BMT-CCR2-/- mice. The present study suggests that CCR2 expression in monocytes has a critical role in vascular inflammation and remodeling in Ang II-induced hypertension, and possibly in other forms of hypertension.  相似文献   
92.
The accumulation of uremic toxins is involved in the progression of CKD. Various uremic toxins are derived from gut microbiota, and an imbalance of gut microbiota or dysbiosis is related to renal failure. However, the pathophysiologic mechanisms underlying the relationship between the gut microbiota and renal failure are still obscure. Using an adenine-induced renal failure mouse model, we evaluated the effects of the ClC-2 chloride channel activator lubiprostone (commonly used for the treatment of constipation) on CKD. Oral administration of lubiprostone (500 µg/kg per day) changed the fecal and intestinal properties in mice with renal failure. Additionally, lubiprostone treatment reduced the elevated BUN and protected against tubulointerstitial damage, renal fibrosis, and inflammation. Gut microbiome analysis of 16S rRNA genes in the renal failure mice showed that lubiprostone treatment altered their microbial composition, especially the recovery of the levels of the Lactobacillaceae family and Prevotella genus, which were significantly reduced in the renal failure mice. Furthermore, capillary electrophoresis–mass spectrometry-based metabolome analysis showed that lubiprostone treatment decreased the plasma level of uremic toxins, such as indoxyl sulfate and hippurate, which are derived from gut microbiota, and a more recently discovered uremic toxin, trans-aconitate. These results suggest that lubiprostone ameliorates the progression of CKD and the accumulation of uremic toxins by improving the gut microbiota and intestinal environment.  相似文献   
93.
94.
Background Medication for the relief of heartburn should have the rapid onset of action required for on-demand use. We studied the inhibition of gastric acid secretion by lafutidine and rabeprazole, given in single doses to fasting and postprandial subjects.Methods A total of 22 healthy male, Helicobacter pylori-negative volunteers participated in this randomized, two-way crossover study. They were randomly assigned to receive a single oral dose of 10mg lafutidine or 20mg rabeprazole after fasting overnight (12 subjects, fasting study) or after eating a test meal (noodles, 364kcal; protein, 10.1g; fat, 16g; carbohydrates, 44.9g; NaCl, 1.1g; 10 subjects, postprandial study). Intragastric pH was monitored continuously for 6h after treatment. The other drug was given after a washout period of at least 7 days, and intragastric pH was similarly monitored.Results In the fasting study, lafutidine sustained pH at >3 and >4 during the second, third, fourth, fifth, and sixth hours of the study for significantly longer than rabeprazole. During the first 6h after treatment, lafutidine sustained pH at more than 2, 3, 3.5, 4, 5, 6, and 7 longer than rabeprazole. In the postprandial study, lafutidine sustained pH >3 and >4 for longer periods than rabeprazole during the third, fourth, fifth, and sixth hours of the study. During the first 6h after treatment, lafutidine sustained pH at more than 2, 3, 3.5, 4, 5, 6, and 7 longer than rabeprazole.Conclusions Lafutidine 10mg produces a prompter rise in intragastric pH than rabeprazole 20mg in fasting and postprandial Helicobacter pylori-negative male subjects.  相似文献   
95.
We describe an XXX female patient accompanied with essential thrombocythemia. To our knowledge this is the first case ever to have been reported. The patient was asymptomatic, but her platelet count had increased to 111.2 x 10(4)/microliter, and she was diagnosed as having essential thrombocythemia based on the diagnostic criteria of the Polycythemia Vera Study Group. At the same time, chromosome analysis of bone marrow cells revealed that she was an XXX female. The patient remained asymptomatic throughout the course of treatment.  相似文献   
96.
97.
98.
The efficient induction of cardiomyocyte differentiation from embryonic stem (ES) cells is crucial for cardiac regenerative medicine. Although Wnts play important roles in cardiac development, complex questions remain as to when, how and what types of Wnts are involved in cardiogenesis. We found that Wnt2 was strongly up-regulated during cardiomyocyte differentiation from ES cells. Therefore, we investigated when and how Wnt2 acts in cardiogenesis during ES cell differentiation. Wnt2 was strongly expressed in the early developing murine heart. We applied this embryonic Wnt2 expression pattern to ES cell differentiation, to elucidate Wnt2 function in cardiomyocyte differentiation. Wnt2 knockdown revealed that intrinsic Wnt2 was essential for efficient cardiomyocyte differentiation from ES cells. Moreover, exogenous Wnt2 increased cardiomyocyte differentiation from ES cells. Interestingly, the effects on cardiogenesis of intrinsic Wnt2 knockdown and exogenous Wnt2 addition were temporally restricted. During cardiomyocyte differentiation from ES cells, Wnt2 didn't activate canonical Wnt pathway but utilizes JNK/AP-1 pathway which is required for cardiomyocyte differentiation from ES cells. Therefore we conclude that Wnt2 plays strong positive stage-specific role in cardiogenesis through non-canonical Wnt pathway in murine ES cells.  相似文献   
99.
Severe skeletal relapse is one of the most difficult problems after mandibular advancement, and the management to overcome such problems tends to require more compromised methods and longer treatment period. We described that mandibular backward distraction osteogenesis with maxillomandibular fixation at an appropriate occlusion. Furthermore, to avoid inappropriate distraction vector, the distal plates of the distraction device were fixed with 1 screw to work as a pivot after the manipulation of the condyle to the glenoid fossa at the end of distraction activation. This technique was applied to 3 female patients with mandibular deficiency. The intraoral distractors were set on the lateral surface of the mandibular body; the fixation of the distal plate was fixed with 1 monocortical screw to make the proximal segment including the condyle manipulating at the end of the distraction phase by releasing the maxillomandibular fixation. The distraction rate was 1 mm/d, and the latency period was 7 days. The follow-up period after mandibular backward distraction osteogenesis ranged from 26 to 56 months. No specific complication, such as broken device, severe infection, or bony nonunion, occurred. Postoperative relapse was not observed during the follow-up period. This technique might become 1 choice to apply for mandibular deficiency in a patient with high risk for relapse.  相似文献   
100.
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