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   24398篇
  免费   1291篇
  国内免费   130篇
耳鼻咽喉   265篇
儿科学   319篇
妇产科学   324篇
基础医学   3291篇
口腔科学   754篇
临床医学   1663篇
内科学   6329篇
皮肤病学   414篇
神经病学   1492篇
特种医学   750篇
外科学   3978篇
综合类   121篇
一般理论   1篇
预防医学   840篇
眼科学   566篇
药学   1653篇
中国医学   68篇
肿瘤学   2991篇
  2023年   106篇
  2022年   231篇
  2021年   400篇
  2020年   232篇
  2019年   297篇
  2018年   423篇
  2017年   327篇
  2016年   414篇
  2015年   404篇
  2014年   532篇
  2013年   656篇
  2012年   994篇
  2011年   1140篇
  2010年   618篇
  2009年   519篇
  2008年   970篇
  2007年   1078篇
  2006年   1058篇
  2005年   1106篇
  2004年   1036篇
  2003年   1094篇
  2002年   977篇
  2001年   893篇
  2000年   909篇
  1999年   868篇
  1998年   294篇
  1997年   241篇
  1996年   254篇
  1995年   217篇
  1994年   182篇
  1993年   166篇
  1992年   690篇
  1991年   619篇
  1990年   572篇
  1989年   654篇
  1988年   551篇
  1987年   507篇
  1986年   517篇
  1985年   474篇
  1984年   303篇
  1983年   234篇
  1982年   134篇
  1981年   100篇
  1980年   111篇
  1979年   222篇
  1978年   174篇
  1977年   137篇
  1974年   111篇
  1971年   120篇
  1969年   126篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Many reports about the increase of renal cell carcinoma patients have been published in Japan recently, however, the real fluctuations in the total number of patients in relation to the change of population have not been reported yet. Most of the patients with renal cell carcinoma in the last 10 years were examined in Chiba prefecture, which has a population of about five million and 25 active urological offices. Histologically confirmed cases were investigated by sending questionnaire letters. The items were as follows; sex, age, address, occupation, family history, past history, symptoms, examination methods that first detected the tumor, operation date, tumor diameter and clinical stage. Twenty two offices returned answers and 560 cases who lived in Chiba were found to have renal cell carcinoma from 1980 to 1989. Yearly incidence rates per 100,000 persons demonstrated a significant increase from 0.32 to 2.07. Small, asymptomatic and low stage cancers have been increasing rapidly, however, the rate of metastatic disease has not shown any decrease. The main cause of rapid increase seems to be attributed to progress in diagnostic methods and increase of early detection, but the possibility of an increase in some carcinogenic factors can not be ruled out.  相似文献   
52.
In recent studies, site-directed mutagenesis has been used to alter the tripeptide glycosylation recognition sequences of glycoprotein hormone subunits, thereby affecting their structure and function. However, it is not known whether these effects result from changes in glycosylation status, amino acid sequence, or both. We therefore studied the synthesis of wild-type and mutant recombinant human thyrotropins produced by transient transfection of a human cell line. Mutating the TSH-beta subunit glycosylation recognition sequence, Asn-Thr-Thr (codons 23-25), to either Gln-Thr-Thr or Asn-Thr-Tyr abolished subunit glycosylation, as demonstrated by the inability to incorporate 3H-carbohydrates. However, a third mutation (Asn-Thr-Ser) contained an intact glycosylation recognition sequence site, and was shown to retain glycosylation. The mutations that abolished TSH-beta subunit glycosylation resulted in greater than 90% decreases in TSH synthesis. However, the glycosylation recognition sequence mutant that retained beta subunit glycosylation exhibited a 70% decrease in TSH production. These decreases were not attributable to the intracellular accumulation of TSH or its free beta subunit. We also engineered two TSH-beta subunit mutations that did not alter the glycosylation recognition sequence. A glycine to arginine mutation adjacent to the glycosylation recognition sequence, in a region thought to be critical for heterodimer formation, abolished TSH production. In contrast, shortening the TSH-beta subunit carboxyterminus by six amino acids increased TSH synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
53.
54.
Primary extranodal malignant lymphoma frequently occurs in the gastrointestinal tract; however, it is rarely encountered in the rectum. We report herein the case of an 85-year-old man who underwent abdominoperineal resection for primary malignant lymphoma of the rectum, and 1 year later, developed hematemesis caused by gastric metastasis. To our knowledge this is the first case report of such distant metastasis developing from malignant lymphoma of the rectum.  相似文献   
55.
Kimura's disease is a rare disorder that involves regional lymph nodes and the major salivary glands, which become infiltrated by eosinophils and lymphocytes. Renal lesions associated with Kimura's disease are rare. We describe the case of a 60-year-old Japanese woman who first noted a nodular mass in a salivary gland. As the nodule grew, nephrotic syndrome and heart failure developed. A biopsy of the nodule revealed Kimura's disease, and surgical excision was performed. After the operation, the heart failure and nephrotic syndrome, which were diagnosed as minimal change disease on renal biopsy, improved rapidly without steroid therapy. Four months later, the nephrotic syndrome recurred without recurrence of Kimura's disease. The patient showed marked improvement during prednisolone therapy (40 mg/d) and was in complete remission 4 weeks after the initiation of steroid therapy. This case shows that surgical excision and prednisolone therapy are useful for nephrotic syndrome associated with Kimura's disease.  相似文献   
56.
We report on a family with ataxia type 6 (SCA6) showing peculiar oculomotor symptoms. The proband presented with periodic alternating nystagmus (PAN), and her 2 brothers had rebound nystagmus and gaze-evoked nystagmus. They carried the identical mutation (the number of expanded CAG repeat, 24) in the CACNA1A gene. The intrafamilial variability of oculomotor symptoms may be ascribed to factors other than CAG repeat expansion size in SCA6.  相似文献   
57.
58.
We examined the localization of basic fibroblast growth factor (basic FGF) in the adult rat brain by immunohistochemical and Western blotting analysis using a specific antibody against a synthetic basic FGF fragment (N-terminal 12 residues). The antibody did not cross-react with acidic FGF. Basic FGF-like immunoreactivity was located exclusively in the neuronal elements and had very heterogenous distribution. Immunoreactive cell bodies were observed in the paraventricular, supraoptic and circular nuclei of the hypothalamus. Numerous immunoreactive neuronal processes originating from these basic FGF-positive cells extended lateroventrally and then caudally to the internal layer of the median eminence. In addition, the neurohypophysis contained a significant number of basic FGF-like immunoreactive fibers. Western-blotting analysis revealed that the hypothalamus and the hypophysis contained a main band of basic FGF immunoreactive with an apparent molecular weight of 17 kDa. These results show that the hypothalamo-hypophyseal neuroendocrine pathway contains basic FGF.  相似文献   
59.
60.
A simplified technique of the liver transplantation under hypothermia has been studied in dog. An immersion hypothermia was used in both the donor and the recipient. The temperature of the graft at excision was lowered to 20 degrees C with supplemental use of topical cooling. The temperature of the recipient was lowered at 27 degrees C when the transplantation was attempted. Chlorpromazine and dopamine were employed beneficially in hypothermia. No perfusion or irrigation of the graft was performed. The use of heparin was avoided. Anastomoses were carried out in turn of the proximal vena cava, portal vein, distal vena cava and the hepatic artery with a stem shaped aorta. Reperfusion was established after the completion of anastomosis between the proximal vena cava and portal vein. The anhepatic phase of the recipient was uneventfully lasted without heparinization. All dogs, 5 out of 11 without early surgical troubles survived more than 5 days. Immunosuppressive therapy was not employed except one which died of pneumonia on the 19th postoperative day. Histologically, these dogs were free from ischemic injury and/or thrombotic lesion throughout transplantation procedure.  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