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   968篇
  免费   53篇
  国内免费   4篇
耳鼻咽喉   3篇
儿科学   18篇
妇产科学   6篇
基础医学   116篇
口腔科学   22篇
临床医学   59篇
内科学   198篇
皮肤病学   24篇
神经病学   79篇
特种医学   45篇
外科学   160篇
综合类   6篇
预防医学   69篇
眼科学   4篇
药学   84篇
肿瘤学   132篇
  2024年   2篇
  2023年   17篇
  2022年   39篇
  2021年   53篇
  2020年   27篇
  2019年   29篇
  2018年   32篇
  2017年   20篇
  2016年   21篇
  2015年   24篇
  2014年   28篇
  2013年   35篇
  2012年   62篇
  2011年   56篇
  2010年   31篇
  2009年   27篇
  2008年   49篇
  2007年   42篇
  2006年   48篇
  2005年   44篇
  2004年   37篇
  2003年   26篇
  2002年   31篇
  2001年   20篇
  2000年   14篇
  1999年   22篇
  1998年   5篇
  1997年   6篇
  1996年   12篇
  1995年   9篇
  1994年   4篇
  1993年   8篇
  1992年   23篇
  1991年   20篇
  1990年   10篇
  1989年   9篇
  1988年   16篇
  1987年   14篇
  1986年   14篇
  1985年   7篇
  1984年   3篇
  1983年   4篇
  1982年   2篇
  1979年   4篇
  1978年   2篇
  1972年   3篇
  1971年   2篇
  1968年   1篇
  1967年   4篇
  1965年   1篇
排序方式: 共有1025条查询结果,搜索用时 0 毫秒
61.
62.
Rat experimental models using Ar-butyl-Af-(4-hydroxybutyl) nitrosamine(BBN) as an initiating agent have been widely used to studycarcinogenic processes in the urinary bladder. In this study,early neoplastic lesions from 10 male F344 rats treated with0.05% BBN for 16 weeks were analyzed for changes in the H-rasor p53 genes by polymerase chain reaction (PCR)-single strandconformation polymorphism (SSCP) analysis and subsequent DNAsequencing. Lesions were pooled for each of the 10 rats andsix showed point mutations in the p53 gene and one in the H-rasgene. These results would indicate that BBNinduced rat urinarybladder carcinomas are similar to human urinary bladder carcinomaswith respect to alterations in the p53 and H-ras genes and thatp53 gene alterations are relatively early events in rat urinarybladder carcinogenesis induced by BBN treatment  相似文献   
63.
To elucidate whether common genetic events in human urinarybladder carcinogenesis also occur in rodent models, we investigatedthe presence of p53, H- and K-ras mutations in 18 urinary bladdercarcinomas induced by various concentrations of N-butyl-N-(4-hydroxybutyl)nitrosamine(BBN) in male NON/Shi mice. Histopathologically, all were invasive,11 being squamous cell carcinomas (SCCs) and the remaining sevenbeing transitional cell carcinomas (TCCs). Using polymerasechain reaction single-strand conformation polymorphism (PCR-SSCP)analysis followed by DNA sequencing, p53, H- and K-ras mutationswere observed in 14 (78%; exons 5–7), two (11%; one eachon exons 1 and 2) and one (5.6%; exon 1) animals respectively.The frequencies of mutations in p53 exons 5, 6 and 7 were 7(39%), 4 (22%), and 9 (50%) respectively, and no mutation wasfound in exon 8. All mutations involved one base-pair substitutionwith or without amino acid changes and the types of base-pairsubstitution were random. No evident association was observedbetween mutation sites and the histological phenotypes. In conclusion,p53 mutations are frequent in BBN-induced mouse invasive urinarybladder tumors, at similar levels to those observed for humanhigh-grade invasive carcinomas, and this plus their distributionsuggests their possible participation in this model of urinarybladder carcinogenesis.  相似文献   
64.
65.
Prostatic cancer is rarely diagnosed by detection of lung metastases. We report a case of prostatic cancer in a 73-year-old man detected by abnormalities in chest X-ray and serum prostate specific antigen (PSA) level. He was initially admitted to our hospital due to elevation of PSA level. On the first transperineal prostatic needle biopsy, prostatic cancer was not detected and he was followed. Seven months after the first biopsy, chest X-ray revealed multiple abnormal nodules in the lung fields bilaterally and PSA level was again elevated. A second prostatic biopsy and whole-body examination were performed, and he was diagnosed with moderately differentiated prostatic adenocarcinoma with multiple lung metastases. Complete androgen blockade therapy was performed immediately. Two months after the beginning of treatment, PSA level was normalized and the multiple lung metastases had completely disappeared. There has been no evidence of recurrence or PSA relapse 24 months after detection of the prostatic cancer. This is the 26th case of prostatic cancer diagnosed in Japan following detection of multiple lung metastases.  相似文献   
66.
A case of bilateral renal cell carcinoma in a 42-year-old polycystic kidney male is reported. He had been treated with hemodialysis for 22 years. An abnormal small mass was found in one of the left renal cystic lesions by screening ultrasonography and CT scan at the 19th year of the hemodialysis. Left radical nephrectomy was performed and the histological diagnosis was a renal cell carcinoma (RCC). There was no evidence of recurrence and metastasis, however, he presented with asymptomatic macrohematuria two years after the operation. CT scan demonstrated the rapidly progressing right renal tumor and multiple para-aortic lymph node swelling. Right nephrectomy and lymphadenectomy were performed and pathological examination showed the advanced RCC with multiple lymph node metastasis. Eleven months after the second operation followed by interferon therapy. he died of multiorgan metastasis of the RCC. This is the first bilateral RCC case in polycystic kidney patient treated with hemodialysis in Japan.  相似文献   
67.
In order to clarify smokers' characteristics by "Stages of Change" based on Prochaska's transtheoretical model, we conducted cross-sectional and logitudinal studies with biochemical markers of smoking and smoking habits. In a workplace-based sample of 277 male smokers, we examined cross-sectionally the relationships between stages and biochemical markers of smoking which include expired carbon monoxide concentrations and urinary nicotine metabolite concentrations, and smoking habits which include the number of cigarettes smoked per day, yields of cigarettes, inhalation patterns, time to first morning cigarette, and quit attempts in the past. Additionally we examined longitudinally the relationship between stages and expired carbon monoxide concentrations, the number of cigarettes, and yields of cigarettes. In the cross-sectional study there were significant differences among stages on expired carbon monoxide concentrations (P = 0.006), urinary nicotine metabolite concentrations (P = 0.049), the number of cigarettes smoked per day (P = 0.001), and yields of cigarettes (P = 0.042) using analyses of variance. There were also significant differences among stages on time to first morning cigarette (P = 0.018) and quit attempts in the past (P < 0.001) using chi-square tests. In the longitudinal study for each level of elevation in stage during a one-year period, expired carbon monoxide concentrations decreased on an average of 2.3 ppm (P = 0.125) and the number of cigarettes smoked per day decreased on an average of 2.8 cigarettes per day (P = 0.07). However, the yields of cigarettes did not change during the one-year period.  相似文献   
68.
69.
To improve the prognosis after hepatectomy for HCC, repeated postoperative transcatheter arterial infusions of anticancer drugs and lipiodol (TAI) were given. TAI may be effective as an adjuvant therapy for prevention of residual liver recurrence after hepatectomy, probably by suppression of the development of intrahepatic micrometastases rather than of multicentric carcinogenesis.  相似文献   
70.
We report a case of abdominal wall abscess caused by diverticulitis of the jejunum penetrating through the abdominal wall. A 53-year-old Japanese woman visited a local hospital complaining of abdominal pain and a mass in the left lower abdomen. An abdominal computed tomography scan showed a tumor with isodensity in the left lower abdominal wall. Magnetic resonance imaging showed a mass in the abdominal wall with isointensity in the T1-intensified image and high intensity in the T2-intensified images. The mass was heterogeneous inside and protruded partially toward the intraperitoneal cavity. Ultrasound examination showed a heteroechoic mass extending into the intraperitoneal cavity. Laparotomy revealed a tumor in the abdominal wall with a fistulous tract extending to the jejunum. We resected the abdominal wall tumor with partial resection of the small intestine. The resected specimen contained a tumor with a fistulous tract passing through the abdominal wall. Histological examination revealed remarkable infiltration of neutrophils and a bacterial mass in the abdominal wall tumor, with a fistulous tract connected to the area adjacent to the mesenteric border of the jejunum. These findings suggested that diverticulitis of the jejunum had penetrated through the abdominal wall, leading to the formation of an abscess. We report this case to highlight the need for complete gastrointestinal evaluation with gastrointestinal barium studies and imaging analysis to examine extension of intra-abdominal lesions in patients with an unexplained abdominal wall abscess.  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