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   5992篇
  免费   339篇
  国内免费   53篇
耳鼻咽喉   65篇
儿科学   178篇
妇产科学   91篇
基础医学   820篇
口腔科学   169篇
临床医学   479篇
内科学   1400篇
皮肤病学   122篇
神经病学   499篇
特种医学   146篇
外国民族医学   1篇
外科学   770篇
综合类   118篇
一般理论   3篇
预防医学   246篇
眼科学   225篇
药学   555篇
  2篇
中国医学   60篇
肿瘤学   435篇
  2023年   57篇
  2022年   111篇
  2021年   155篇
  2020年   79篇
  2019年   115篇
  2018年   135篇
  2017年   123篇
  2016年   154篇
  2015年   148篇
  2014年   191篇
  2013年   227篇
  2012年   307篇
  2011年   396篇
  2010年   217篇
  2009年   196篇
  2008年   367篇
  2007年   387篇
  2006年   339篇
  2005年   368篇
  2004年   330篇
  2003年   292篇
  2002年   285篇
  2001年   92篇
  2000年   73篇
  1999年   76篇
  1998年   54篇
  1997年   47篇
  1996年   44篇
  1995年   28篇
  1994年   37篇
  1993年   21篇
  1992年   71篇
  1991年   66篇
  1990年   53篇
  1989年   56篇
  1988年   64篇
  1987年   63篇
  1986年   58篇
  1985年   51篇
  1984年   41篇
  1983年   23篇
  1982年   29篇
  1979年   30篇
  1978年   30篇
  1977年   34篇
  1976年   25篇
  1973年   22篇
  1972年   22篇
  1970年   24篇
  1967年   20篇
排序方式: 共有6384条查询结果,搜索用时 15 毫秒
91.
Recent studies suggest a relationship between intestinal microbiota and metabolic syndromes; however, the underlying mechanism remains unclear. To clarify this issue, we assessed the effects of bacterial cell wall components on adiponectin, leptin and resistin secretion from rat visceral adipocytes in vitro. We also measured the relative population of Firmicutes and Bacteroidetes in fecal microbiota and the amount of fecal mucin as an intestinal barrier function, when mice were fed a high-fat diet. In the present study, we demonstrated that bacterial cell wall components affect the secretion of adipokines, depending on the presence of antigens from gram-positive or gram-negative bacteria. Lipopolysaccharide markedly inhibited adiponectin, leptin, and resistin secretion, whereas peptidoglycan increased adiponectin secretion and decreased resistin secretion in vitro. In vivo experiments showed that the high-fat diet increased the population of Firmicutes and decreased that of Bacteroidetes. In contrast, the high-fat diet downregulated the stool output and fecal mucin content. These results demonstrate that bacterial cell wall components affect the onset of metabolic syndromes by mediating the secretion of adipokines from visceral adipose tissue. Furthermore, we believe that metabolic endotoxemia is not due to the increasing dominance of gram-negative bacteria, Bacteroidetes, but due to the depression of intestinal barrier function.  相似文献   
92.
We investigated the changes in energy expenditure during induction therapy in patients with severe or moderate ulcerative colitis. Thirteen patients (10 men, 3 women; mean age, 36.5 years) with ulcerative colitis admitted to the Shiga University Hospital were enrolled in this study. We measured the resting energy expenditure and respiratory quotients of these patients before and after induction therapy with indirect calorimetry. We analyzed the changes of nutritional status and serum inflammatory cytokine levels and also evaluated the relationship between energy metabolism and disease activity by using the Seo index and Lichtiger index. The resting energy expenditure was 26.3 ± 3.8 kcal/kg/day in the active stage and significantly decreased to 23.5 ± 2.4 kcal/kg/day after induction therapy (p<0.01). The resting energy expenditure changed in parallel with the disease activity index and C-reactive protein and inflammatory cytokine levels. The respiratory quotient significantly increased after induction therapy. Thus, moderate to severe ulcerative colitis patients had a hyper-metabolic status, and the energy metabolism of these patients significantly changed after induction therapy. Therefore, we recommend that nutritional management with 30–34 kcal/kg/day (calculated as measured resting energy expenditure × activity factor, 1.3) may be optimal for hospitalized ulcerative colitis patients.  相似文献   
93.
Reduced port surgery has been attracting attention in the field of minimally invasive surgery. Although the use of SILS is becoming widespread, technical difficulty has delayed its adoption for laparoscopic liver resection. Recently, advances in laparoscopic liver resection have been made in tandem with advances in surgical skill and devices. The main driver in conventional laparoscopic liver resection's evolution to become less surgically invasive seems to be single‐incision laparoscopic liver resection (SILLR). To date, most reports on SILLR have been single case reports or case series. Only a few cohort studies on conventional laparoscopic surgery and SILLR have been conducted. Recent reports have described the use of SILLR for well‐localized lesions and solitary tumors located in the anterolateral segments of the liver or left liver lobe, but its application remains limited to partial resection and left lateral sectionectomy. The feasibility and safety of SILLR have been demonstrated, but additional work is needed for standardization of the procedure.  相似文献   
94.
Blood flow volume of the portal venous system of 3 patients with splenic artery aneurysm, an uncommon disease, was measured using an ultrasonic duplex system. A huge increase in splenic blood flow volume was found in each case. A large portasystemic shunt through which the portal blood flowed hepatofugally was present in 2 cases. We suspect the shunt is partially responsible for an increase in splenic blood flow volume, which would lead to the formation of splenic artery aneurysm together with portal hypertension.  相似文献   
95.
The Cytochrome P450 is the major enzyme involved in drug metabolism. CYP enzymes are responsible for the metabolism of most clinically used drugs. Individual variability in CYP activity is one important factor that contributes to drug therapy failure. We have developed a new straightforward TaqMan PCR genotyping assay to investigate the prevalence of the most common allelic variants of polymorphic CYP enzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A5 in the Japanese population. Moreover, we focused on the combination of each genotype for clinical treatment. The genotype analysis identified a total of 139 out of 483 genotype combinations of five genes in the 1,003 Japanese subjects. According to our results, most of subjects seemed to require dose modification during clinical treatment. In the near future, modifications should be considered based on the individual patient genotype of each treatment.  相似文献   
96.
种植体周围炎是种植义齿常见的并发症,是导致种植义齿失败的主要原因。种植体表面去污会影响种植体周围炎手术治疗的疗效,是种植体周围骨缺损重建前的必要处理步骤。由于良好的杀菌和去污能力,激光疗法和光动力学疗法在处理污染种植体表面上拥有良好的应用前景。本文就不同种植体表面去污的方法及其联合手术疗法治疗种植体周围炎的效果作一归纳总结。  相似文献   
97.
98.
Cognitive impairment has long been recognized as a complication of chronic kidney disease. However, there is little information available regarding regional cerebral blood flow (rCBF) in patients with peritoneal dialysis (PD). Therefore, we evaluated rCBF using brain single photon emission computed tomography (SPECT). We conducted a cross‐sectional study in our hospital. Eighteen consecutive PD patients who could visit the hospital by themselves without any history of stroke were examined by Technetium‐99 m‐labeled ethylcrysteinate dimer brain SPECT. An easy Z‐score imaging system (eZIS) was used to compare rCBF in PD patients with those in age‐matched healthy controls. We also evaluated cognitive dysfunction with the mini‐mental state examination (MMSE) questionnaire. Only one patient showed an MMSE score of 18 points, and the remaining 14 patients were considered as normal (MMSE ≥ 27), and three patients were considered to have mild cognitive impairment (24 ≤ MMSE ≤ 26). In all patients, rCBF in the posterior cingulated gyri, precunei, and parietal cortices was significantly decreased. The ratio of the reduction of rCBF in each region relative to that of rCBF across the whole brain correlated positively with the PD duration (r = 0.559; P < 0.05). The serum β2‐microglobulin level was significantly higher in patients who had a higher ratio of rCBF reduction compared with those with lower ratios. In conclusion, all PD patients in the present study had decreased rCBF irrespective of MMSE scores.  相似文献   
99.
100.
G protein-coupled receptors (GPCRs) are seven-transmembrane proteins that mediate most cellular responses to hormones and neurotransmitters, representing the largest group of therapeutic targets. Recent studies show that some GPCRs signal through both G protein and arrestin pathways in a ligand-specific manner. Ligands that direct signaling through a specific pathway are known as biased ligands. The arginine-vasopressin type 2 receptor (V2R), a prototypical peptide-activated GPCR, is an ideal model system to investigate the structural basis of biased signaling. Although the native hormone arginine-vasopressin leads to activation of both the stimulatory G protein (Gs) for the adenylyl cyclase and arrestin pathways, synthetic ligands exhibit highly biased signaling through either Gs alone or arrestin alone. We used purified V2R stabilized in neutral amphipols and developed fluorescence-based assays to investigate the structural basis of biased signaling for the V2R. Our studies demonstrate that the Gs-biased agonist stabilizes a conformation that is distinct from that stabilized by the arrestin-biased agonists. This study provides unique insights into the structural mechanisms of GPCR activation by biased ligands that may be relevant to the design of pathway-biased drugs.  相似文献   
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