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   1911篇
  免费   90篇
  国内免费   17篇
耳鼻咽喉   17篇
儿科学   69篇
妇产科学   24篇
基础医学   238篇
口腔科学   38篇
临床医学   117篇
内科学   312篇
皮肤病学   18篇
神经病学   161篇
特种医学   159篇
外科学   370篇
综合类   29篇
预防医学   57篇
眼科学   33篇
药学   176篇
中国医学   2篇
肿瘤学   198篇
  2024年   2篇
  2023年   14篇
  2022年   40篇
  2021年   63篇
  2020年   33篇
  2019年   47篇
  2018年   38篇
  2017年   26篇
  2016年   43篇
  2015年   45篇
  2014年   57篇
  2013年   86篇
  2012年   142篇
  2011年   148篇
  2010年   75篇
  2009年   79篇
  2008年   152篇
  2007年   137篇
  2006年   137篇
  2005年   111篇
  2004年   114篇
  2003年   95篇
  2002年   92篇
  2001年   21篇
  2000年   16篇
  1999年   28篇
  1998年   13篇
  1997年   9篇
  1996年   7篇
  1995年   12篇
  1994年   5篇
  1993年   11篇
  1992年   17篇
  1991年   15篇
  1990年   13篇
  1989年   19篇
  1988年   12篇
  1987年   6篇
  1986年   5篇
  1985年   2篇
  1984年   3篇
  1983年   3篇
  1982年   4篇
  1981年   3篇
  1980年   5篇
  1979年   4篇
  1975年   2篇
  1972年   1篇
  1970年   1篇
  1966年   1篇
排序方式: 共有2018条查询结果,搜索用时 0 毫秒
1.
2.
The aqueous extract of the fruits of Terminalia chebula Retz. has been evaluated for its antidiabetic activity in streptozotocin (STZ) induced mild diabetic rats and compared with a known drug, tolbutamide. The oral effective dose (ED) of the extract was observed to be 200 mg/kg body weight, which produced a fall of 55.6% (p<0.01) in the oral glucose tolerance test. Oral administration of ED of aqueous extract of T.chebula (AETC) daily once for two months reduced the elevated blood glucose by 43.2% (p<0.01) and significantly reduced the increase in glycosylated hemoglobin (HbA1c) (p<0.01). The same dose also showed a marked improvement in controlling the elevated blood lipids as well as decreased serum insulin levels in contrast to the untreated diabetic animals. Hepatic and skeletal muscle glycogen content decreased by 75% and 62.9% respectively in diabetic controls, these alterations were partly prevented (34.9% and 21.17%) in AETC treated group when compared to the healthy controls. The in vitro studies with pancreatic islets showed that the insulin release was nearly two times more than that in untreated diabetic animals. The treatment did not have any unfavorable effect on other blood parameters of liver and kidney function tests. LD 50 was found to be above 3 g/kg bw i.e. 15 times of ED, because there were no deaths of animals even at this dose indicating high margin of safety. These findings suggest further investigations for the possible use of the aqueous extract of fruits of T.chebula for the treatment of diabetes.  相似文献   
3.
4.
5.
Oral Submucous Fibrosis is an insidious, chronic disease affecting the oral cavity, sometimes the pharynx and rarely the tongue. 15 patients with Oral Submucous Fibrosis presenting with severe trismus were treated with lysis of the fibrotic bands with a KTP-532 Laser and adjunctive treatment with excellent results over a 12 month follow-up period.  相似文献   
6.
Bronchiolitis obliterans syndrome (BOS) is a major cause of lung allograft dysfunction. Although previous studies have identified mild to severe rejection (grade>or=A2) as a risk factor for BOS, the role of minimal rejection (grade A1) remains unclear. To determine if A1 rejection by itself is a risk factor for BOS, we performed a retrospective cohort study on 228 adult lung transplant recipients over a 7-year period. Cohorts were defined by their most severe rejection episode (none, A1 only, and >or=A2) and analyzed for the subsequent development and progression of BOS using univariate and multivariate time-dependent Cox regression analysis. In the univariate model, the occurrence of isolated minimal rejection was a risk factor for all stages of BOS. Similarly, multivariate models that included HLA mismatch, cytomegalovirus pneumonitis, community acquired viral infection, underlying disease and type of transplant demonstrated that A1 rejection was a distinct risk factor for BOS. Furthermore, the associated risk with A1 rejection was slightly greater than the risk from >or=A2 and treatment of A1 rejection decreased the risk for subsequent BOS stage 1. We conclude that minimal rejection is associated with an increased risk for BOS development and progression that is comparable to A2 rejection.  相似文献   
7.
Presented are the results of an extensive noninvasive assessment of supraclinoid internal carotid artery (ICA) stenosis with moyamoya-like vasculopathy in 3 patients with a history of stroke. Five noninvasive criteria for the diagnosis based on magnetic resonance imaging of the brain, and hemodynamic testing using ocular pneumoplethysmography, duplex carotid ultrasound, and transcranial Doppler sonography were established: (1) normal ocular pneumoplethysmography demonstrating no pressure significant stenosis to the level of the ophthalmic artery; (2) abnormal Doppler spectral waveforms showing either no flow or a high-resistance flow pattern for the ipsilateral cervical internal carotid artery; (3) paradoxically low flow velocities for the ipsilateral intracranial (ICA) and middle cerebral artery (MCA), and markedly abnormal high velocities for the contralateral ICA and MCA; (4) decreased ipsilateral MCA vasomotor reactivity; and (5) deep MCA territory ipsilateral subcortical watershed infarction evidenced by magnetic resonance imaging. This report demonstrates that a noninvasive battery of tests may be useful in the early diagnosis and treatment of these patients.  相似文献   
8.
Nasopharyngeal carcinoma (NPC) is a rare malignancy world-wide. It shows an increasing trend in the southern parts of India. Genetic alterations brought about by environmental factors, HPV and EBV are thought to be crucial for NPC carcinogenesis. This study reports for the first time the incidence of HPV infection in NPC in Southern India. Detection of HPV was carried out in 36 NPC and 10 adenoid lesions by immunohistochemical analysis. 38.8% of NPC were positive for HPV with higher positivity in WHO Type I and WHO Type II cancers. One among 10 adenoid lesions also showed presence of HPV. The patients belonged to low socio-economic status and had exposure to either tobacco or alcohol alone or in combination or kitchen smoke.  相似文献   
9.
Prostate-specific antigen (PSA) production by nonprostatic tissues has been reported, casting doubts on its specificity. The immunohistochemical relative specificity and sensitivity of PSA expression using monoclonal and polyclonal anti-PSA was analyzed on 60 prostate carcinomas, 40 normal seminal vesicles, and 310 nonprostatic tumors. All nonprostatic tumors proved negative with both antibodies. However, 13 (32%) seminal vesicles showed immunoreactivity with polyclonal anti-PSA, but none showed immunoreactivity with the monoclonal antibody. The sensitivity of the 2 antibodies for prostate cancer varied with tumor grade. In Gleason pattern 3, both antibodies showed diffuse immunostaining in all cases. In Gleason pattern 5, polyclonal anti-PSA showed diffuse (>95%) tumor cell positivity in 18 cases (90%), while with the monoclonal antibody, 7 cases (35%) showed only focal (<10%) tumor cell immunoreactivity. Thus, monoclonal anti-PSA seems to be useful in small gland proliferations in which the differential diagnosis includes seminal vesicle, while for poorly differentiated neoplasms, polyclonal anti-PSA is considered superior. Sections of high-grade prostate cancer should be included as positive controls for PSA immunostaining.  相似文献   
10.
Malignant melanoma of soft parts (MMSP) was originally described as a distinct entity by Enzinger in 1965 and was termed “clear cell sarcoma of tendons and aponeuroses” because of its association with tenosynovial structures. It has been shown immunophenotypically and ultrastructurally that this tumor is derived from neuroectoderm and shares a number of features with cutaneous melanoma. Over 95% of MMSPs present in the extremities, with the head and neck region (1.9%) being an unusual site. This study presents an additional case of MMSP of the head and neck region involving the posterior cervical region in a 15-year-old Hispanic male and reviews the literature on MMSP. Ultrastructural examination showed rudimentary cell attachments, smooth cell membranes, discontinuous basal lamina, scanty glycogen, and occasional premelanosomes in some tumor cells. Cytogenetic analysis showed a reciprocal translocation between the long arms of chromosomes 12 and 22 [t(12:22)(q13;q12.2)], characteristic for MMSP and not seen in cutaneous melanoma. Survival in MMSP has been correlated with tumor size, tumor necrosis, and ploidy status. Overall reported clinical outcome for this tumor is as follows: died of disease, 45%; alive with disease, 23%; no evidence of disease, 30%; and died of other causes, 2%. MMSP represents a distinct entity with a characteristic ultrastructural appearance and a tumor defining cytogenetic translocation.  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