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   2692篇
  免费   215篇
  国内免费   11篇
耳鼻咽喉   21篇
儿科学   104篇
妇产科学   112篇
基础医学   414篇
口腔科学   88篇
临床医学   288篇
内科学   532篇
皮肤病学   117篇
神经病学   220篇
特种医学   36篇
外科学   192篇
综合类   51篇
一般理论   4篇
预防医学   210篇
眼科学   67篇
药学   229篇
中国医学   50篇
肿瘤学   183篇
  2024年   6篇
  2023年   49篇
  2022年   66篇
  2021年   194篇
  2020年   164篇
  2019年   189篇
  2018年   188篇
  2017年   107篇
  2016年   140篇
  2015年   116篇
  2014年   157篇
  2013年   188篇
  2012年   249篇
  2011年   236篇
  2010年   118篇
  2009年   83篇
  2008年   116篇
  2007年   106篇
  2006年   89篇
  2005年   93篇
  2004年   61篇
  2003年   32篇
  2002年   33篇
  2001年   4篇
  1999年   6篇
  1998年   3篇
  1997年   4篇
  1996年   2篇
  1995年   4篇
  1994年   3篇
  1993年   5篇
  1992年   5篇
  1991年   4篇
  1990年   5篇
  1989年   5篇
  1988年   8篇
  1987年   13篇
  1986年   6篇
  1985年   12篇
  1984年   6篇
  1983年   3篇
  1982年   2篇
  1980年   4篇
  1979年   8篇
  1977年   3篇
  1976年   4篇
  1973年   3篇
  1972年   2篇
  1970年   3篇
  1936年   1篇
排序方式: 共有2918条查询结果,搜索用时 46 毫秒
1.
2.
Cancer Chemotherapy and Pharmacology - Despite all advances in the treatment of ovarian cancer (OC), it remains the most lethal gynecological malignancy worldwide. There are growing amounts of...  相似文献   
3.
The World Health Organization has reported an annual global suicide rate of 14.5 per 100,000 people. On the other hand, it is estimated that approximately one‐third of the global population are infected with Toxoplasma gondii (T. gondii) parasite. It is widely assumed that microbial pathogens, such as T. gondii, are probably associated with affective and behavioural modulation. The present article aimed to assess the proposed role of toxoplasmosis in raising the risk of suicidal ideation (SI) and suicide attempts (SA) using the available epidemiological data. Seven major electronic databases and the Internet search engine Google were searched for all the studies published between the 1st of January 1950 and 31st of October 2019. The heterogeneity and the risk of bias within and across studies were assessed. Following data extraction, pooled odds ratios (ORs) with 95% confidence interval (CI) across studies were calculated using the random‐effects models. A total number of 9,696 articles were screened and 27 studies were regarded as eligible in our systematic review (SI with five papers and 22 papers on SA). A significant association was detected between antibodies against T. gondii with TA (ORs = 1.57; 95% confidence interval [CI] 1.23–2.00, p = .000). Exploration of the association between T. gondii and SA yielded a positive effect of seropositivity for IgG antibodies but not IgM. Despite the limited number of studies, a statistical association was detected between suicidal behaviours and infection with latent T. gondii.  相似文献   
4.
Introduction Iniencephaly, a neural tube defect involving occiput and inion and combined with rachischisis of the cervical, thoracic spine, and retroflexion position of the head is a very rare congenital abnormality of the fetus–newborn with a 0.1–10 of 10,000 prevalence. This abnormality’s prognosis is thought to be dismal. This abnormality can be associated with other abnormalities such as anencephaly, encephalocele, hydrocephalus, cyclopia, absence of the mandible, cleft lip and palate, cardiovascular disorders, diaphragmatic hernia, renal abnormalities, overgrowth of the arms compared to the legs, and club food and gastrointestinal atresia. Discussion Most of the patients are dead born, and the others die in a few hours. There are only six previously documented long-term survivors. In our case, our patient with iniencephalic signs and findings is still living. She is 2 years old now. We think that this patient presents a mild form of iniencephaly.  相似文献   
5.
A topographic CEEG investigation was carried out in 20 drug-free, DSM-IIIR diagnosed schizophrenics and in a group of matched healthy controls. The effects of acute and chronic haloperidol treatment were then assessed in the patient group. On the baseline recording, schizophrenics showed a widespread increase in delta, theta 1 and beta 3 amplitude. Acute haloperidol administration produced a decrease in delta and an increase in slow beta amplitude. After 28 days of treatment, delta and fast beta were reduced while theta 2 and alpha 1 were increased. CEEG abnormalities in schizophrenic subjects appear, therefore, to be reduced by chronic neuroleptic treatment.  相似文献   
6.
Aim: Rheumatoid arthritis (RA) is the most common chronic inflammatory erosive joint disease with the worldwide distribution of approximately 0.5–1.0%. Etiology of RA is not exactly known but immunologic and genetic factors play an important role in the pathogenesis of the disease. Genetic factors such as human leukocyte antigens (HLA) are responsible for many autoimmune diseases; therefore we decided to look for a correlation between RA and the presence of HLA‐DQβ1 alleles as possible genetic markers. Methods: Genomic DNA from the whole blood samples of 25 patients with RA and 86 normal individuals as control group were extracted by salting out method. The genomic DNA was amplified by polymerase chain reaction‐sequence specific primer (PCR‐SSP) technique. HLA‐typing was done by this method after optimizing the PCR reaction for each allele. In this procedure seven serological subclasses of HLA‐DQβ1 can be detected. Results: Comparing the results between the patients and controls show a significant increase in the frequency of HLA‐DQ8 (*0302, *0305) alleles in RA patients. The P‐values were 0.007 and the relative risk for these alleles was evaluated higher than 1. Conclusions: The results suggest that DQ8 is the dominant HLA‐DQβ1 allele that is associated with susceptibility to RA in north‐eastern Iran.  相似文献   
7.
8.
Objective Teratoma is the most frequently encountered intracranial tumor at birth and constitutes 18–20% of all germ cell tumors. They are usually located in pineal and suprasellar regions. The authors aim to report an extremely unusual presentation, location, and appearance of a teratoma in a newborn. Case report A soft tissue swelling in the vertex was detected in a 1-month-old girl. Neurological examination was normal. A big, cystic–solid lesion beginning from pineal region and extending to the scalp was detected in magnetic resonance imaging. It is interesting to note that cerebral venous angiography showed that the superior sagittal sinus (SSS) was divided into three branches at the level of the lesion and they joined together distally. The tumor was excised totally. Histopathological examination revealed the diagnosis of a mature cystic teratoma. Conclusion A mature cystic teratoma mimicking parietal encephalocele is extremely rare. Germ cell tumors should be kept in mind in the differential diagnosis of all midline lesions with unusual radiographic appearance. Cerebral venous angiography or MR angiography must be performed for the diagnosis and the surgical planning in lesions located near SSS.  相似文献   
9.
Sputum and serum from patients with active pulmonary tuberculosis (TB), healthy purified protein derivative-positive adults, and patients with bacterial pneumonia were collected to simultaneously assess local immunity in the lungs and peripheral blood. To determine whether cytokine profiles in sputum from TB patients and control subjects were a reflection of its cellular composition, cytospin slides were prepared in parallel and assessed for the presence of relative proportions of epithelial cells, neutrophils, macrophages, and T cells. Gamma interferon (IFN-γ) in sputum from TB patients was markedly elevated over levels for both control groups. With anti-TB therapy, IFN-γ levels in sputum from TB patients decreased rapidly and by week 4 of treatment were comparable to those in sputum from controls. Further, IFN-γ levels in sputum closely followed mycobacterial clearance. Although detected at fourfold-lower levels, IFN-γ immunoreactivities in serum followed kinetics in sputum. TNF-α, interleukin 8 (IL-8) and IL-6 also were readily detected in sputum from TB patients at baseline and responded to anti-TB therapy. In contrast to IFN-γ, however, TNF-α and IL-8 levels also were elevated in sputum from pneumonia controls. These data indicate that sputum cytokines correlate with disease activity during active TB of the lung and may serve as potential early markers for sputum conversion and response to anti-TB therapy.  相似文献   
10.
The pathophysiologic basis for the exuberant intracellular growth of Mycobacterium avium complex (MAC) in AIDS patients is unclear but may relate to altered expression of modulatory cytokines. Interleukin (IL)-1, IL-6, and TNF- expression by monocytes from AIDS patients and healthy subjects (HS) stimulated with isogeneic MAC strains (SmT, smooth-transparent, virulent; SmD, smooth-domed, avirulent) was examined. Spontaneous cytokine production was not observed in patients with AIDS. MAC strains induced less IL-1 and IL-1 release in AIDS patients than HS (P < 0.05). The ratio of cell-associated to supernatant IL-1 also was increased in AIDS patients (P = 0.03). IL-1 mRNA expression paralleled protein release in either group of subjects. In both HS and AIDS patients, stimulation with SmD induced more IL-1 and TNF- release by monocytes compared to SmT. In AIDS patients, SmD also induced greater IL-6 release than SmT (P < 0.01). Alterations in monocyte expression and compartmentalization of the regulatory cytokines IL-1 and IL-6 may enhance bacterial replication and contribute to the patho-genesis of MAC infection in AIDS.  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