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   6152篇
  免费   254篇
  国内免费   22篇
耳鼻咽喉   23篇
儿科学   107篇
妇产科学   54篇
基础医学   838篇
口腔科学   78篇
临床医学   349篇
内科学   1548篇
皮肤病学   61篇
神经病学   532篇
特种医学   287篇
外科学   1258篇
综合类   19篇
预防医学   180篇
眼科学   131篇
药学   365篇
中国医学   5篇
肿瘤学   593篇
  2023年   36篇
  2022年   69篇
  2021年   130篇
  2020年   78篇
  2019年   99篇
  2018年   123篇
  2017年   96篇
  2016年   110篇
  2015年   121篇
  2014年   176篇
  2013年   229篇
  2012年   370篇
  2011年   395篇
  2010年   199篇
  2009年   168篇
  2008年   344篇
  2007年   400篇
  2006年   391篇
  2005年   410篇
  2004年   389篇
  2003年   402篇
  2002年   357篇
  2001年   60篇
  2000年   56篇
  1999年   76篇
  1998年   98篇
  1997年   94篇
  1996年   87篇
  1995年   79篇
  1994年   64篇
  1993年   62篇
  1992年   58篇
  1991年   52篇
  1990年   60篇
  1989年   44篇
  1988年   37篇
  1987年   39篇
  1986年   38篇
  1985年   24篇
  1984年   42篇
  1983年   34篇
  1982年   40篇
  1981年   20篇
  1980年   27篇
  1979年   11篇
  1978年   15篇
  1977年   13篇
  1976年   12篇
  1974年   15篇
  1973年   11篇
排序方式: 共有6428条查询结果,搜索用时 15 毫秒
91.
· Background: Choroideremia (CHM) is an X-linked progressive dystrophy of the choroid, retinal pigment epithelium, and retina. Recently, the REP-1 gene was isolated and the causative mutations in the gene were detected in patients with CHM. In a previous study, we described a Japanese family with CHM who had a mutation in the REP-1 gene. In the present study, we performed extensive analysis of the REP-1 gene in patients with CHM from several institutions in Japan. · Methods: Twenty-six patients with CHM and 5 unaffected females from 22 independently ascertained families were examined. Exons 1–15 of the REP-1 gene were screened by single-strand conformation polymorphism. The DNA fragments suspected of any variations were directly sequenced. · Results: Fifteen different mutations, including one previously reported mutation, were detected in 18 families. In addition, carrier status was proven in four unaffected females found to be heterozygous for the mutant allele. · Conclusions: Fifteen different mutations of the REP-1 gene were detected in 18 Japanese families. There were no hot spots for the mutations and no missense mutations. The results show that REP-1 gene defects cause CHM in Japanese patients, and the mutations in these Japanese patients differed from the mutations reported for CHM patients in Europe, Canada, and America except for R267X and 1313delTC. These findings suggest that the mutations occurred independently in the Japanese patients. Received: 13 August 1998 Revised version received: 16 November 1998 Accepted: 9 December 1998  相似文献   
92.
Tsutomu  Ohtsuka  MD    Akira  Hasegawa  MD    Akihiko  Nakano  MD    Akio  Yamakage  MD    Mary  Yamaguchi  MD  Yoshiki  Miyachi  MD 《International journal of dermatology》1997,36(2):116-122
Background Patients with systemic sclerosis (SSC) show a capillary abnormality of nailfolds with controversial correlation with organ involvement. Our purpose was to study the correlation between this nailfold capillary abnormality and pulmonary hypertension in patients with SSC. Methods We studied the nailfold capillaries, using capillary microscopy, and the pulmonary arterial pressure, using right-heart catheterlzation, in 44 patients with SSC. Canonical discriminant analysis was used to define the capillary abnormality in patients with SSC, which was then compared with that of 40 normal controls. The correlations between the patterns of nailfold capillaries and the cardiopulmonary findings. Including the pulmonary arterial pressure, were examined using Fisher's test. Results Thirty-two of 44 patients with SSC could be differentiated from normal controls by our definition of the SSC pattern. The SSC pattern correlated significantly with elevated pulmonary vascular resistance, as well as with pulmonary fibrosis, eiectrocardiographic abnormalities, decreased vital capacity, and decreased diffusing capacity for carbon monoxide. All SSC patients with pulmonary hypertension showed this SSC pattern. In patients with elevated pulmonary arterial pressure, capillary microscopy and diffusion capacity for carbon monoxide (DCCM) showed the highest rate of abnormalities. A limited-type SSC significantly correlated with DCCM and with anticentromere antibody, and the diffuse-type SSC with pulmonary fibrosis and anti-sci-70 antibody. Conclusion Our data suggest that in patients with SSC, nailfold capillary abnormalities correlate with pulmonary arterial hypertension as well as with clinical and laboratory findings indicating pulmonary hypertension.  相似文献   
93.
Abstract Human α1(I) and α1(III) procollagen mRNA expression in skin tissue from 15 systemic sclerosis (SSc) patients and from 7 normal control subjects was quantitatively analyzed using in situ hybridization. The grains accumulating in each area, representing procollagen mRNA expression per cell, were counted. To normalize the results from each subject, the number of cells and the number of grains per cell were divided by the area of the skin specimen (in square millimeters). The number of cells per square millimeter expressing α<1(I) and α1(III) procollagen mRNA in SSc skin was significantly elevated compared with normal control skin (both P < 0.01). The number of grains per cell per square millimeter expressing α1(III) procollagen mRNA in SSc skin was also significantly elevated compared with normal control skin (P < 0.01). The relationship between procollagen mRNA expression and the histological findings in SSc was also studied. The numbers of cells and grains per cell per square millimeter expressing α1(I) procollagen mRNA in fibrotic zone SSc skin were significantly elevated compared with normal control skin (both P < 0.01). The numbers of cells and grains per cell per square millimeter expressing α1(III) procollagen mRNA in SSc skin were significantly elevated compared with normal control skin (both P < 0.01) and with border zone SSc skin (number of cells P < 0.01, number of grains P < 0.05). These results indicate an increase in the number of cells showing elevated expression of α1(I) and α1(III) procollagen mRNA, and a close relationship between α1(I) and α1(III) procollagen mRNA expression and the histological findings in SSc. Received: 24 February 1999 / Received after revision: 20 May 1999 / Accepted: 16 August 1999  相似文献   
94.
BACKGROUND: Many patients with acute myocardial infarction will still die after admission. Recent trends in hospital mortality were analyzed to identify aspects that need improvement. METHODS AND RESULTS: A total of 1,247 patients admitted to Kinki University School of Medicine within 24 h of the onset of infarction were analyzed between 1975 and 2001. The percentage of patients discharged with 100% occlusion decreased gradually from 31.3% during 1975-1982 to 2.1% during 1998-2001, while those with 50% stenosis or less gradually increased from 12.5% to 82.5% during the same period (trends: p < 0.01). The cardiac death rate was 17.1% in 1975-1982, and 7.7% in 1998-2001, showing a significant decrease with time (p < 0.01). This decrease was particularly marked among those admitted within 6 h of the onset of infarction. Death due to cardiac rupture decreased significantly with time (p < 0.001). In contrast, the non-cardiac death rate, amounting to 2.2% on average, did not decline. CONCLUSIONS: Cardiac deaths due to acute myocardial infarction have decreased markedly of late. However, patients must be admitted within 6 h of the onset of infarction to benefit from this improvement. More effort should be made to improve the general care of patients in order to reduce the incidence of non-cardiac death.  相似文献   
95.
96.
97.
We screened patients with choroideremia using next-generation sequencing (NGS) and identified a novel mutation and a known mutation in the CHM gene. One patient presented an atypical fundus appearance for choroideremia. Another patient presented macular hole retinal detachment in the left eye. The present case series shows the utility of NGS-based screening in patients with choroideremia. In addition, the presence of macular hole in 1 of the 2 patients, together with a previous report, indicated the susceptibility of patients with choroideremia to macular hole.Key Words: Choroideremia, Next-generation sequencing, Diagnosis, Utility  相似文献   
98.
99.
Journal of Gastroenterology - In clinical practice, rectal cancer (RC) is classified according to tumor location. However, RC’s genetic characteristics according to tumor location remain...  相似文献   
100.
Anomalous coronary arteries are usually identified incidentally by angiography or autopsy, but some "malignant" coronary anomalies are associated with a high incidence of syncope, arrhythmia, myocardial infarction, and sudden death. So far, the pathogenesis of the coronary events in such cases has only been revealed by autopsy. In the present case report, a patient with anomalous origin of the right coronary artery from the left sinus of Valsalva developed acute myocardial infarction, and visualization of the anomaly and assessment of the culprit plaque in the artery were done by multidetector row computed tomography and intravascular ultrasound.  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