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   8831篇
  免费   321篇
  国内免费   55篇
耳鼻咽喉   145篇
儿科学   187篇
妇产科学   82篇
基础医学   1094篇
口腔科学   107篇
临床医学   661篇
内科学   2199篇
皮肤病学   75篇
神经病学   580篇
特种医学   437篇
外科学   1523篇
综合类   29篇
预防医学   237篇
眼科学   306篇
药学   583篇
中国医学   28篇
肿瘤学   934篇
  2023年   30篇
  2022年   74篇
  2021年   118篇
  2020年   53篇
  2019年   77篇
  2018年   112篇
  2017年   95篇
  2016年   131篇
  2015年   135篇
  2014年   200篇
  2013年   303篇
  2012年   474篇
  2011年   571篇
  2010年   334篇
  2009年   323篇
  2008年   564篇
  2007年   632篇
  2006年   598篇
  2005年   649篇
  2004年   694篇
  2003年   684篇
  2002年   673篇
  2001年   96篇
  2000年   96篇
  1999年   105篇
  1998年   159篇
  1997年   124篇
  1996年   119篇
  1995年   109篇
  1994年   97篇
  1993年   107篇
  1992年   72篇
  1991年   64篇
  1990年   62篇
  1989年   54篇
  1988年   60篇
  1987年   43篇
  1986年   26篇
  1985年   33篇
  1984年   30篇
  1983年   16篇
  1982年   23篇
  1981年   22篇
  1980年   34篇
  1979年   26篇
  1978年   23篇
  1977年   15篇
  1976年   9篇
  1974年   8篇
  1971年   9篇
排序方式: 共有9207条查询结果,搜索用时 31 毫秒
991.
A 30 year old female was admitted with right upper abdominal pain and fever. Ultrasonography and computed tomography revealed a large cystic mass in the right lobe of the liver, and aspiration bacteriology was negative. A right hepatic lobectomy was performed for a suspected cystadenocarcinoma, however, the tumor was histologically diagnosed as a hemangiopericytoma with prominent venous invasion. The patient died within a short time of multiple pulmonary metastases. Primary hepatic hemangiopericytoma is extremely rare, and according to our research, this is only the 4th case reported in the literature.  相似文献   
992.
Total IgE and specific IgE antibodies to common allergens were determined by the enzyme-linked im-munosorbent assay in children with Mycoplasma pneumoniae or respiratory syncytial virus (RSV) infections. The decrease of total IgE from the acute to convalescent phase was observed in 105 of 134 (78.4%) children with M. pneumoniae infection and in 40 of 49 (81.6%) of those with RSV infection. Similarly, many patients showed a decrease of the responses of specific IgE in the convalescent phase of the infections. The results indicated that these infections might alter the production of total IgE and IgE specific to common allergens unrelated to the infectious agents.  相似文献   
993.
994.
Two aged women suddenly suffered from severe cervical and back pain followed by ipsilateral hemiparesis sparing the face. One woman had taken anticoagulant for prosthetic mitral valve and another had taken antiplatelet for prevention of recurrent brain infarction. On admission, MRI did not document any definite lesions in the brain, and revealed epidural hematoma compressing the cervical spinal cord for both patients. We promptly stopped their anticoagulants and antiplatelets use, because the agents seemed to be the leading cause of hematoma. In addition, we performed emergent laminectomy and evacuation of hematoma for the former patient. These cases suggest dual warnings against recently prevalent antithrombotic therapy for patients with histories of thromboembolic accidents. First, we should be careful about spinal epidural hematoma as a hemorrhagic complication of antithrombotic therapy. Second, we should not misdiagnose spinal epidural hematoma as ischemic stroke nor select hyperacute thrombolytic therapy. Cervical pain and hemiparesis sparing face are important signs for distinction of spinal epidural hematoma from stroke.  相似文献   
995.
We present a rare case of recurrent dedifferentiated liposarcoma of the spermatic cord which was clearly depicted by FDG-PET imaging. Preceding the FDG study, it was difficult to discriminate whether a mass detected by CT was recurrent tumor or postradiation necrosis. The FDG-PET finding was informative in relation to the extent of a viable tumor. We suggest that FDG-PET seems to be useful in differentiating recurrent tumor from radiation necrosis in patients with liposarcoma after therapy.  相似文献   
996.
Summary: Chronic localized encephalitis (Rasmussen's syndrome) developed in an 11-year-old girl 1 month after operation for residual cataract due to chronic uveitis that had appeared at age 9 years ipsilateral to the affected cerebral hemisphere. Although the pathogenesis of Rasmussen's syndrome remains unknown, our case provides additional evidence indicating that a viral ocular infection is a possible cause or part of the disorder.  相似文献   
997.
In order to create the least restrictive setting in psychiatric practice, we investigated the effects of an assessment by a committee on seclusion and restraint. Using consistent procedures, the committees, which were established in 9 hospitals, reviewed seclusion and restraint maintained for periods of over 2 weeks during a 4-month period. Frequency and duration of seclusion and restraint, staff perceptions of and attitudes to the review system, and patient satisfaction were evaluated before and after the study period. As a result of this review process, the frequency of seclusion decreased slightly in 7 hospitals and 1 of the remaining 2 hospitals showed an increased frequency of seclusion days that were partially interrupted. Frequency of restraint decreased slightly in 5 hospitals, and of the remaining 3, 1 interrupted all periods of restraint, while the other 2 institutions showed an increase in interruption of restraint periods. As there were no common patients in 2 specialist psychiatric emergency hospitals between before and after the study periods, statistical analyses were performed. Only minor variables such as duration of partially interrupted periods of restraint, and duration of periods of restraint that were partially released showed a statistically significant increase. Although patient satisfaction showed a significant increase, staff attitudes to and perceptions of the review system became appreciably more negative. These findings suggest that although the review system had the potential to slightly reduce the use of seclusion and restraint, and to increase patient satisfaction, staff burnout was risked because staff effort was perceived to be disproportionately high in relation to the effect achieved. Furthermore, the possibility remains that the slight decrease of seclusion and restraint demonstrated did not necessarily reflect the appropriate use of these strategies, and were not necessarily lasting effects. However, as differences in opinion existed between the review system committee and treating clinicians regarding continuation of long term seclusion and restraint, the review system could have a role in monitoring the long term use of seclusion and restraint. Further investigation is needed into the long term effectiveness of procedures reviewing the use of seclusion and restraint in the psychiatric setting, taking into account both positive and negative outcomes.  相似文献   
998.
Background: Acute upper gastrointestinal hemorrhage is a common and life‐threatening medical emergency. Despite a large number of endoscopic methods for hemostasis, active bleeding lacks an adequate therapeutic remedy. The aim of the present study was to evaluate the hemostatic effect of argon plasma coagulation on upper gastrointestinal active bleeding, especially in comparison with heater probe and pure ethanol injection therapy. Methods: Sixty‐eight patients with 77 lesions presenting active bleeding were treated endoscopically and divided into three groups depending on the procedures, that is, argon plasma coagulation group (27 patients with 32 lesions), heater probe group (20 patients with 22 lesions) and pure ethanol injection group (21 patients with 23 lesions). The three groups were similar with respect to all background variables. Episodes of rebleeding were retreated with the same modality as used previously. Results: The primary hemostatic rate in the argon plasma coagulation group was 81.3%, that in the heater probe group was 77.3%, and that in the pure ethanol injection group was 87.0%. The permanent hemostatic rate in the argon plasma coagulation group was 75.0%, that in the heater probe group was 63.6%, and that in the pure ethanol injection group was 78.3%. When examined in terms of Forrest's criteria, the argon plasma coagulation group in Forrest's type I b and the pure ethanol injection group in type I a showed the highest permanent hemostatic rate. Conclusions: Argon plasma coagulation is most suitable in arresting oozing hemorrhage. If pure ethanol injection therapy is possible, it is more effective than other therapies in the case of spurters.  相似文献   
999.
Pyridoxine dependent seizure (PDS) is a disorder of neonates or infants with autosomal recessive inheritance characterized by seizures, which responds to pharmacological dose of pyridoxine. Recently, mutations have been identified in the ALDH7A1 gene in Caucasian families with PDS. To elucidate further the genetic background of PDS, we screened for ALDH7A1 mutations in five PDS families (patients 1-5) that included four Orientals. Diagnosis as having PDS was confirmed by pyridoxine-withdrawal test. Exon sequencing analysis of patients 1-4 revealed eight ALDH7A1 mutations in compound heterozygous forms: five missense mutations, one nonsense mutation, one point mutation at the splicing donor site in intron 1, and a 1937-bp genomic deletion. The deletion included the entire exon 17, which was flanked by two Alu elements in introns 16 and 17. None of the mutations was found in 100 control chromosomes. In patient 5, no mutation was found by the exon sequencing analysis. Furthermore, expression level or nucleotide sequences of ALDH7A1 mRNA in lymphoblasts were normal. Plasma pipecolic acid concentration was not elevated in patient 5. These observations suggest that ALDH7A1 mutation is unlikely to be responsible for patient 5. Abnormal metabolism of GABA/glutamate in brain has long been suggested as the underlying pathophysiology of PDS. CSF glutamate concentration was elevated during the off-pyridoxine period in patient 3, but not in patient 2 or 5. These results suggest allelic and non-allelic heterogeneities of PDS, and that the CSF glutamate elevation does not directly correlate with the presence of ALDH7A1 mutations.  相似文献   
1000.
Antiangiogenic therapy, including blockade of vascular endothelial growth factor (VEGF) signaling, was highly anticipated to improve the prognosis for patients with advanced cancers following the success of preclinical animal models. However, antiangiogenic monotherapy with VEGF antagonists has produced disappointing results in clinical trials to date. One of the reasons for this poor outcome is that angiogenesis is not solely regulated by VEGF. Inhibition of VEGF signaling, therefore, may select for tumor cell populations that stimulate angiogenesis through VEGF-independent pathways. Successful antiangiogenic therapy, therefore, may require simultaneous blockade of signaling downstream from multiple proangiogenic factor receptors. Recently, we found that non-receptor protein-tyrosine kinases, including members of the Src and Fes families, play vital roles in the responses of cultured endothelial cells to several proangiogenic factors. In this review, we summarize the contributions of these kinase families to angiogenic pathways in endothelial cells, and discuss the potential of these kinases as new targets for antiangiogenic drug discovery.  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