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   176323篇
  免费   1068篇
  国内免费   7篇
耳鼻咽喉   1138篇
儿科学   6687篇
妇产科学   3058篇
基础医学   16608篇
口腔科学   1605篇
临床医学   12472篇
内科学   30795篇
皮肤病学   699篇
神经病学   16525篇
特种医学   9082篇
外科学   28957篇
综合类   2386篇
预防医学   18099篇
眼科学   2737篇
药学   9497篇
中国医学   647篇
肿瘤学   16406篇
  2019年   27篇
  2018年   21945篇
  2017年   17382篇
  2016年   19528篇
  2015年   906篇
  2014年   812篇
  2013年   793篇
  2012年   6960篇
  2011年   21001篇
  2010年   18835篇
  2009年   11528篇
  2008年   19504篇
  2007年   21706篇
  2006年   539篇
  2005年   2156篇
  2004年   3348篇
  2003年   4329篇
  2002年   2459篇
  2001年   312篇
  2000年   463篇
  1999年   207篇
  1998年   274篇
  1997年   264篇
  1996年   132篇
  1995年   126篇
  1994年   129篇
  1993年   90篇
  1992年   56篇
  1991年   103篇
  1990年   141篇
  1989年   113篇
  1988年   90篇
  1987年   69篇
  1986年   48篇
  1985年   65篇
  1984年   38篇
  1983年   39篇
  1982年   41篇
  1980年   52篇
  1977年   24篇
  1976年   24篇
  1974年   28篇
  1969年   24篇
  1939年   25篇
  1938年   60篇
  1937年   25篇
  1935年   23篇
  1934年   32篇
  1932年   56篇
  1930年   50篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
101.
Background Insular thyroid carcinoma was described as a tumor with aggressive behavior, and patients usually present themselves with an advanced tumor stage. Whether the insular component is an independent factor for poor prognosis remains unclear. Therefore, in the present study, we compared the survival of patients with advanced insular, follicular, and papillary thyroid cancer. Materials and methods The clinical behavior of tumors in three groups of patients with T4 thyroid carcinoma—8 patients with insular, 11 patients with follicular, and 21 patients with papillary thyroid carcinomas—was compared. Disease-free survival and disease-specific death were analyzed statistically. Cox regression analysis was used to evaluate the influence of histotype and other prognostic factors. Results At 3 years, survival was 37.5% (mean 26 months) among patients with insular thyroid carcinoma, 80% (mean 59 months) among those with follicular, and 89% (mean 126 months) among those with papillary thyroid carcinomas (p = 0.007). Disease-free survival in patients without initial distant metastasis was worst in patients with insular thyroid carcinoma (20%) compared to those with follicular (75%) and those with papillary thyroid carcinomas (71%). Conclusion Patients with advanced insular thyroid carcinoma have a poorer outcome in comparison to patients with similar advanced stage who have follicular or papillary thyroid carcinoma.  相似文献   
102.
Isolated pure dislocations of the fifth carpo-metacarpal joint are extremely rare injuries. The dorsal form was described in mere 12 cases. The diagnosis can be easily missed. The lesion is also often overlooked in the routine diagnostic X-ray. Lateral and oblique views are important for the recognition of the true extent of the lesion. Treatment of these injures is still controversial and both closed reduction with percutaneous pinning or open reduction with internal fixation are advocated. The goal of treatment is early reduction and fixation of the metacarpal. Early diagnosis is the key to success. The aim of this paper is to review literature and present two new cases.  相似文献   
103.
With a view to the development of new controlled drug delivery systems, the formation of an interpolyelectrolyte complex (IPEC) between chitosan (CTS) and Eudragit L100 (L-100) has been studied. The structure of this IPEC is such that two maxima are observed in the curves of IPEC swelling in the media with different pH values. The release of a model drug (ibuprofen) from IPEC-based tablets is significantly retarded, and this delay can be controlled by changing the molecular weight of CTS in the IPEC composition. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 39, No. 12, pp. 44–46, December, 2005.  相似文献   
104.
Introduction Amisulpride is a substituted benzamide that, at low doses, selectively blocks D2 and D3 presynaptic dopamine receptors, enhancing dopaminergic transmission in frontal cortex and limbic areas. Many clinical studies versus placebo, tricyclic antidepressants and selective serotonin reuptake inhibitors showed amisulpride antidepressant effect, supporting its safety and rapid onset of action. In oncological population, depression is quite frequent and difficult to treat because of the particular sensitivity of cancer patients to the antidepressants’ side effects. Goals of work The aims of this study were to evaluate efficacy, safety and tolerability of low doses of amisulpride (50 mg) in oncological, depressed patients during chemotheraphy. Materials and methods One hundred six consecutive cancer outpatients with depressive symptoms were treated in a prospective, intention to treat, 4-week study, and were evaluated in single-blind with Montgomery Asberg rating scale for depression (MADRS), clinical global impression (CGI) and dosage record treatment emergent symptom scale (DOTES) to assess side effects of treatment. Main results After 4 weeks of treatment, scores of MADRS and CGI significantly improved (p < 0.002; p < 0.001, respectively), with a reduction of depressive symptoms concerning both emotional (such as apparent sadness, reported sadness, inner tension, etc.) and physical cluster (such as lack of appetite, reduction in weight, tiredness and insomnia) with good tolerability (only two patients dropped out). Conclusions This study is the first trial on the use of amisulpride in a cohort of oncological, depressed patients during chemotherapy. Amisulpride demonstrated high efficacy and safety. Controlled studies are needed to confirm these preliminary data.  相似文献   
105.
The implantation of chondrocytes, seeded on matrices such as hyaluronic acid or collagen membranes, is a method that is being widely used for the treatment of chondral defects. The aim of the present study was to evaluate the distribution, viability and phenotype expression of the cells seeded on a collagen membrane just at the time of the implantation. Twelve patients who were suffering from articular cartilage lesions were treated by the MACI® procedure. The residual part of each membrane was tested by colorimetric assay (MTT) and histochemical and ultrastructural analyses were carried out. In all of the samples a large number of viable cells, quite homogenously distributed, was detected. The cells expressed the markers of the differentiated hyaline chondrocytes. These data reassure in that the MACI procedure provides a suitable engineered tissue for cartilage repair, in line with the clinical evidences emerging in the literature.  相似文献   
106.
Chronically elevated levels of corticotropin-releasing factor (CRF) in transgenic mice overexpressing CRF in the brain (CRF-OE) appear to be associated with alterations commonly associated with major depressive disorder, as well as with sensorimotor gating deficits commonly associated with schizophrenia. In the present study, we tested the hypothesis that antipsychotics may be effective in normalizing prepulse inhibition (PPI) of acoustic startle in CRF-OE mice, which display impaired sensorimotor gating compared to wild-type (WT) mice. The typical antipsychotic haloperidol and atypical antipsychotic risperidone improved PPI in the CRF-OE mice, but were ineffective in WT mice. The atypical antipsychotic clozapine did not influence PPI in CRF-OE mice, but reduced gating in WT mice. This effect of clozapine in the CRF-OE mice may thus be regarded as a relative improvement, consistent with the observed effect of haloperidol and risperidone. As expected, the anxiolytic, nonantipsychotic chlordiazepoxide was devoid of any effect. All four compounds dose-dependently reduced the acoustic startle response irrespective of genotype. These results indicate that antipsychotic drugs are effective in improving startle gating deficits in the CRF-OE mice. Hence, the CRF-OE mouse model may represent an animal model for certain aspects of psychotic depression, and could be a valuable tool for research addressing the impact of chronically elevated levels of CRF on information processing.  相似文献   
107.
We experienced a rare case of giant cell tumor (GCT) arising in the 5th rib involving the 5th vertebral body and transverse process. A 57-year-old man presented with a well-defined mass in the left thoracic cavity on chest x ray examination. Chest computed tomography showed a heterogeneous 7cm-diameter mass originating in the posterior segment of the left 5th rib. The tumor had spread to the 5th thoracic vertebra destroying the left half of the body and transverse process. Magnetic resonance imaging showed a heterogeneous-intensity mass involving the 4th to 6th ribs. A radical excision of the tumor followed by a 50 Gy radiotherapy was performed after embolization of the feeding arteries. The pathological diagnosis was a GCT. The patient remains well without evidence of recurrence for 6 years following surgery. The present case is only the 14th case of GCT arising in the rib to have been reported in Japan.  相似文献   
108.

Purpose  

Hepatitis B virus (HBV) is endemic in Bangladesh, and the quality of life (QoL) of these patients remains unknown as there is no instrument available in the native language. In this study, we translated the 56-item Hepatitis Quality of Life Questionnaire (HQLQ) into Bengali and evaluated its validity and reliability.  相似文献   
109.
Healthcare information systems (HISs) are often implemented to enhance the quality of care and the degree to which it is patient-centered, as well as to improve the efficiency and safety of services. However, the outcomes of HIS implementations have not met expectations. We set out to organize the knowledge gained in qualitative studies performed in association with HIS implementations and to use this knowledge to outline an updated structure for implementation planning. A multi-disciplinary team performed the analyses in order to cover as many aspects of the primary studies as possible. We found that merely implementing an HIS will not automatically increase organizational efficiency. Strategic, tactical, and operational actions have to be taken into consideration, including management involvement, integration in healthcare workflow, establishing compatibility between software and hardware and, most importantly, user involvement, education and training. The results should be interpreted as a high-order scheme, and not a predictive theory.  相似文献   
110.
Objective Approximately 10% of patients with neurofibromatosis I (NFI) patients will have central nervous system (CNS) tumors. The most common of these are hypothalamic–optic gliomas, followed by brainstem and cerebellar pilocytic astrocytomas. While isolated pilocytic astrocytomas in NFI are well described, the appearance of multiple pilocytic astrocytomas in an individual patient is less common. The most frequent combination in NFI patients with more than one pilocytic astrocytoma is optic tract/hypothalamic and brainstem. Other combinations are exceedingly rare; multiple pilocytic astrocytomas have only been reported once in the cerebral hemispheres in a patient with NFI. This report presents the first documented case, to our knowledge, of multiple pilocytic astrocytomas in the cerebellum of a patient with NF1. Methods Case report. Conclusion The finding of multiple cerebellar pilocytic astrocytomas in a patient with NF1 is important because it expands the spectrum of presentations for patients with NF1 and also highlights specific diagnostic and therapeutic challenges faced by the treating physicians. The genetic and molecular basis of NF1 is reviewed. Strategies of diagnosis and treatment outlined here are relevant to both patients with NF1 and all patients with multiple posterior fossa tumors.  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