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   12587篇
  免费   824篇
  国内免费   48篇
耳鼻咽喉   187篇
儿科学   285篇
妇产科学   236篇
基础医学   1801篇
口腔科学   1183篇
临床医学   1016篇
内科学   2765篇
皮肤病学   348篇
神经病学   878篇
特种医学   359篇
外国民族医学   1篇
外科学   1442篇
综合类   67篇
一般理论   6篇
预防医学   1285篇
眼科学   202篇
药学   861篇
中国医学   82篇
肿瘤学   455篇
  2023年   110篇
  2022年   287篇
  2021年   451篇
  2020年   316篇
  2019年   430篇
  2018年   480篇
  2017年   342篇
  2016年   380篇
  2015年   396篇
  2014年   552篇
  2013年   675篇
  2012年   966篇
  2011年   1029篇
  2010年   587篇
  2009年   468篇
  2008年   685篇
  2007年   741篇
  2006年   587篇
  2005年   569篇
  2004年   463篇
  2003年   385篇
  2002年   366篇
  2001年   279篇
  2000年   278篇
  1999年   207篇
  1998年   76篇
  1997年   64篇
  1996年   59篇
  1995年   54篇
  1994年   48篇
  1993年   38篇
  1992年   88篇
  1991年   85篇
  1990年   89篇
  1989年   60篇
  1988年   63篇
  1987年   73篇
  1986年   60篇
  1985年   54篇
  1984年   57篇
  1983年   43篇
  1982年   36篇
  1980年   21篇
  1979年   33篇
  1978年   28篇
  1970年   23篇
  1969年   20篇
  1967年   25篇
  1966年   23篇
  1965年   21篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
The occurrence in chickens of small viruses with bisegmented double-stranded RNA (dsRNA) genome is confirmed and a new virus with similar properties but with three genome segments is described. Both differ from birnaviruses (Intervirology 25, 141-143, 1986) in having indistinct surface structure, smaller diameters (35 nm), and higher buoyant density (1.4 g/ml) in CsCl but are similar in these respects to viruses previously described in several mammals (Lancet 2, 103-104, 1988; J. Gen. Virol. 69, 2749-2754, 1988; Res. Vet. Sci, in press) under the tentative name of picobirnaviruses (PBV). Genome segment length estimations gave values of 2.6 and 1.9 kbp for the avian PBV and 2.9, 2.4 and 0.9 kbp for the trisegmented viruses. The source and pathogenic potential of these viruses remain to be established.  相似文献   
52.
Introduction: Neuropsychiatric systemic lupus erythematosus (NPSLE) is characterized by a heterogeneity of clinical manifestations. The absence of diagnostic criteria and the lack of clinical trials is a challenge in clinical practice.

Areas covered: A literature review was performed to describe epidemiology, characterization (clinical, immunological, and imaging), diagnosis and treatment of NPSLE. Classification criteria have been the first step towards a uniform definition. More recently, different attribution models have been developed to help to determine if the NP event is due to SLE. Disease activity is a major risk factor for NP events. Cytokines and autoantibodies are associated with NP events, however, only a few studies have identified risk factors for individual NP events.

Expert opinion: Further research needs to search for and validate biomarkers for NPSLE and individual NP events, including neuroimaging findings, attribution models, and serologic markers. This will be a fundamental step in planning randomized control trials in the treatment of NPSLE to improve outcome.  相似文献   

53.
The authors evaluated 20 patients, diagnosed by Research Diagnostic Criteria after 1 week of hospitalization as having schizophrenia, weekly throughout their hospitalization. Four patients developed syndromes of depression after resolution of their psychoses: three manifesting a "minor" and one a "major" postpsychotic depressive syndrome. Four other patients went on to develop syndromes equivalent to major depression at a time when they were still actively psychotic, and their cross-sectional diagnoses were therefore changed to schizoaffective disorder, depressed type. The authors discuss the implications of these findings for diagnosis.  相似文献   
54.
55.
In peritoneal dialysis (PD), a cloudy dialysate is an alarming finding. Bacterial peritonitis is the most common cause, however, atypical infections and non‐infectious causes must be considered. A 46‐year‐old man presented with asthenia, paraesthesia, foamy urine and hypertension. Laboratory testing revealed severe azotaemia, anaemia, hyperkalaemia and nephrotic‐range proteinuria. Haemodialysis was started through a central venous catheter. Later, due to patient preference, a Tenckhoff catheter was inserted. Conversion to PD occurred 3 weeks later, during hospitalization for a presumed central line infection. A month later, the patient was hospitalized for neutropenic fever. He was diagnosed an acute parvovirus infection and was discharged under isoniazid for latent tuberculosis. Four months later, the patient presented with fever and a cloudy effluent. Peritoneal fluid (PF) cytology was suggestive of infectious peritonitis, but the symptoms persisted despite antibiotic therapy. Bacterial and mycological cultures were negative. No neoplastic cells were detected. Mycobacterium tuberculosis eventually grew in PF cultures, despite previous negative molecular tests. Directed therapy was then initiated with excellent response. Thus, facing a cloudy effluent, one must consider multiple aetiologies. Diagnosis of peritoneal tuberculosis is hampered by the lack of highly sensitive and specific exams. Here, diagnosis was only possible due to positive mycobacterial cultures.  相似文献   
56.
Pseudoangiosarcomatous squamous cell carcinoma, also called pseudovascular, pseudoangiomatoid or adenoid pseudovascular carcinoma, is an uncommon and highly aggressive variant of squamous cell carcinoma. Histologically, it is characterized by proliferation of atypical keratinocytes with acantholysis and formation of pseudovascular spaces, forming anastomosed channels lined with neoplastic cells that invade the dermis. These cells are positive for cytokeratin and negative for vascular markers such as CD31 and CD34. There are few reports of this variant in the literature. Skin, breast, lung and vulva involvement have been described, but to the best of our knowledge, no cases involving the penis has been described. This study aims to describe the first case of angiosarcomatous squamous cell carcinoma of the penis. The patient presented with a painful lesion in the penis associated with urinary retention. Macroscopic findings exhibited an ulcerative vegetating lesion that involving the entire glans and part of the penile body, as well as infiltration of penile structures and scrotal skin. Microscopy shows atypical proliferation of sarcomatous keratinocyte pattern mimicking vascular spaces. Human papilloma virus (HPV) biomarkers and polymerase chain reaction (PCR) were all negative. Advanced penile squamous cell carcinoma with aggressive lymph node metastasis. This report presents the first case of penile pseudoangiosarcomatous squamous cell carcinoma, as an important differential diagnosis.  相似文献   
57.
58.
A case is presented of an eight-year-old child with a mediastinal tumour, who had developed acute renal failure following the institution of steroid therapy. Intrapleural analgesia was successfully used for the insertion of a peritoneal dialysis catheter so that the considerable risks of general anaesthesia were avoided. Subsequent dialysis allowed chemotherapy to commence and, as a result of the shrinkage in tumour size, general anaesthesia was administered safely two days later. The purpose of this report is to highlight the use of intrapleural analgesia in children as an alternative to general anaesthesia, when the latter is contraindicated. The mechanism of action of intra-pleural analgesia and the risks of anaesthesia in the presence of a mediastinal tumour are discussed.  相似文献   
59.
This paper examines the peculiarities of the expression of emotion in a poor neighborhood from Northeastern Brazil, the bairro of Nordeste de Amaralina, in Salvador, Bahia. Focusing on the expression of sadness, we built a scheme in which to understand how the informants perceive, identify, and deal with this emotion in the course of their daily lives. We attempted to reach an understanding of the wavs people in the bairro interpret sadness. In order to accomplish this goal. we built a semantic network which revealed three main clusters of emotional expression: the inner set, the bodily set, and the interactional set. We came to realize the various superpositions benween the universe of emotional expression and the local concept of person.  相似文献   
60.
This paper aims to discuss which one is the best estimator of past diet: a retrospective report or a recent diet recall. The analysis included 13 articles published between 1984-1997 and selected from a MEDLINE search and from other reviews on this subject. The selection criterion was the use of a food frequency questionnaire (FFQ) in a validation study of retrospective report of dietary intake in remote past. Literature review shows that even taking into account misclassification, retrospective report of diet usually yields to a more reliable estimate of past diet pattern than current report. Past diet recall was strongly influenced by current intake and by diet patterns change. Analyzed investigations indicate that agreement between original and retrospective report was higher either for foods eaten rarely or frequently and lower for foods moderately consumed. This review allows considering the FFQ as a valuable instrument when studying the role of diet on the etiology of chronic diseases.  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