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   2677篇
  免费   141篇
  国内免费   24篇
耳鼻咽喉   28篇
儿科学   40篇
妇产科学   83篇
基础医学   345篇
口腔科学   177篇
临床医学   202篇
内科学   639篇
皮肤病学   106篇
神经病学   166篇
特种医学   30篇
外科学   380篇
综合类   26篇
预防医学   225篇
眼科学   36篇
药学   168篇
中国医学   14篇
肿瘤学   177篇
  2024年   2篇
  2023年   23篇
  2022年   54篇
  2021年   98篇
  2020年   48篇
  2019年   70篇
  2018年   86篇
  2017年   68篇
  2016年   48篇
  2015年   75篇
  2014年   126篇
  2013年   119篇
  2012年   225篇
  2011年   234篇
  2010年   135篇
  2009年   113篇
  2008年   210篇
  2007年   197篇
  2006年   165篇
  2005年   145篇
  2004年   162篇
  2003年   123篇
  2002年   126篇
  2001年   16篇
  2000年   10篇
  1999年   15篇
  1998年   14篇
  1997年   27篇
  1996年   14篇
  1995年   10篇
  1994年   7篇
  1993年   6篇
  1992年   9篇
  1991年   5篇
  1990年   3篇
  1989年   6篇
  1988年   3篇
  1987年   2篇
  1985年   2篇
  1984年   10篇
  1983年   6篇
  1982年   5篇
  1981年   3篇
  1979年   3篇
  1976年   4篇
  1973年   1篇
  1965年   1篇
  1964年   1篇
  1944年   2篇
  1934年   1篇
排序方式: 共有2842条查询结果,搜索用时 46 毫秒
161.
Fusobacterium nucleatum is a gram-negative anaerobe involved in various diseases, including periodontitis. Recently, other investigators isolated the F. nucleatum FDC 364 fusobacterial immunosuppressive protein (FIP). One subunit, FipA, impairs T-cell activation in vitro and shows homology with beta-ketothiolases. However, its distribution and variability among fusobacteria was not reported. Cloned fipA gene sequences from F. nucleatum ssp. polymorphum (ATCC 10953) and F. nucleatum ssp. nucleatum (ATCC 23726) shared 89 and 92% identity, respectively, with FDC 364 fipA, and 90 and 94% identity, respectively, with the FDC 364 FipA predicted amino acid sequence. Southern blot analyses of chromosomal DNA from fusobacterial strains, including F. nucleatum and other Fusobacterium species, were performed using partial fipA sequences as probes. The results indicate that fipA is highly conserved among the F. nucleatum strains examined and that fipA homologues are widely distributed among fusobacteria. A clear relationship between immune suppression, metabolism and the FipA protein remains to be determined.  相似文献   
162.
163.
164.
165.
166.
167.
To examine the association of low-grade systemic inflammation with diabetes, as well as its heterogeneity across subgroups, we designed a case-cohort study representing the approximately 9-year experience of 10,275 Atherosclerosis Risk in Communities Study participants. Analytes were measured on stored plasma of 581 incident cases of diabetes and 572 noncases. Statistically significant hazard ratios of developing diabetes for those in the fourth (versus first) quartile of inflammation markers, adjusted for age, sex, ethnicity, study center, parental history of diabetes, and hypertension, ranged from 1.9 to 2.8 for sialic acid, orosomucoid, interleukin-6, and C-reactive protein. After additional adjustment for BMI, waist-to-hip ratio, and fasting glucose and insulin, only the interleukin-6 association remained statistically significant (HR = 1.6, 1.01-2.7). Exclusion of GAD antibody-positive individuals changed associations minimally. An overall inflammation score based on these four markers plus white cell count and fibrinogen predicted diabetes in whites but not African Americans (interaction P = 0.005) and in nonsmokers but not smokers (interaction P = 0.13). The fully adjusted hazard ratio comparing white nonsmokers with score extremes was 3.7 (P for linear trend = 0.008). In conclusion, a low-grade inflammation predicts incident type 2 diabetes. The association is absent in smokers and African-Americans.  相似文献   
168.
We tested the hypothesis that acute hypoxia may alter the circadian pattern of body temperature in adult humans. Six healthy subjects were studied in normoxia, hypoxia (approximately 13% inspired O(2)), and again normoxia, each session lasting >24 h and spaced a few days apart, with a constant routine protocol of sustained wakefulness and minimal activity. Some parameters (e.g., tympanic and abdominal temperatures, heart rate) were recorded continuously; others (e.g., oxygen consumption and pulmonary ventilation) were monitored for approximately 10 min every 2 h. The amplitudes of the circadian oscillation of tympanic, abdominal, and calf skin temperatures were reduced in hypoxia, averaging, respectively, 61%, 80% and 50% of the normoxic amplitude. Oxygen consumption and pulmonary ventilation, which presented a circadian pattern in normoxia, had no longer significant oscillations during hypoxia, whereas the opposite was the case for heart rate and diastolic pressure. Therefore, acute hypoxia can disturb the normal circadian patterns and, specifically, depress those of body temperature. These effects, qualitatively similar to those observed in chronically hypoxic animals and humans, could contribute to sleep disturbances at high altitude.  相似文献   
169.
A mononucleotide repeat (D310) in mitochondrial DNA has been recently identified as a mutational hot spot in primary tumors. We analyzed 56 tumors for insertion/deletion mutations in the D310 repeat. A total of 13 mutations were detected. The highest frequency of mutations was found for cervical cancer, followed by bladder tumors, breast cancer and endometrial neoplasia. No alterations were observed in four patients suspected of malignancy but without evidence of malignant tumor. We detected identical changes in four of four urine sediments from patients with bladder cancer and in three of three fine needle aspirates of patients with breast cancer. Our results indicate that D310 abnormalities are detectable in cytology specimens from patients with cancer and support the notion that D310 analysis may represent a new molecular tool for cancer detection.  相似文献   
170.
Skin metastases from urothelial carcinoma of the bladder are uncommon, and there are few cases reported in literature. The present case report describes the results of a combination of cyclophosphamide, methotrexate and 5-fluorouracil (CMF) administered as second-line chemotherapy in a cisplatin-resistant metastatic bladder cancer patient. The improvement in cutaneous lesions and pain reduction obtained prompt further exploration of the activity of this regimen in a second-line approach.  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