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   1570篇
  免费   80篇
  国内免费   12篇
耳鼻咽喉   9篇
儿科学   64篇
妇产科学   12篇
基础医学   177篇
口腔科学   57篇
临床医学   218篇
内科学   329篇
皮肤病学   31篇
神经病学   55篇
特种医学   176篇
外国民族医学   1篇
外科学   244篇
综合类   66篇
预防医学   79篇
眼科学   7篇
药学   70篇
中国医学   16篇
肿瘤学   51篇
  2024年   2篇
  2023年   15篇
  2022年   30篇
  2021年   41篇
  2020年   14篇
  2019年   20篇
  2018年   46篇
  2017年   31篇
  2016年   35篇
  2015年   38篇
  2014年   54篇
  2013年   85篇
  2012年   91篇
  2011年   76篇
  2010年   103篇
  2009年   83篇
  2008年   84篇
  2007年   67篇
  2006年   71篇
  2005年   51篇
  2004年   42篇
  2003年   47篇
  2002年   35篇
  2001年   25篇
  2000年   22篇
  1999年   18篇
  1998年   41篇
  1997年   41篇
  1996年   39篇
  1995年   37篇
  1994年   27篇
  1993年   23篇
  1992年   18篇
  1991年   12篇
  1990年   9篇
  1989年   20篇
  1988年   20篇
  1987年   12篇
  1986年   18篇
  1985年   10篇
  1984年   14篇
  1983年   15篇
  1982年   13篇
  1981年   13篇
  1980年   17篇
  1979年   5篇
  1978年   10篇
  1977年   2篇
  1976年   8篇
  1975年   5篇
排序方式: 共有1662条查询结果,搜索用时 29 毫秒
61.
A cell line of Madin-Darby canine kidney (MDCK) cells persistently infected with human influenza A virus has been established and designated as MDCK-IVpi cells. Production of progeny virus in MDCK-IVpi cells was suppressed when the cells were incubated in the presence of 10% fetal calf serum (FCS). FCS impaired virus mRNA synthesis in MDCK-IVpi cells, which resulted in a scarcity of virus proteins for virion formation. However, MDCK-IVpi cells well supported the growth of superinfecting heterologous influenza viruses, even in the presence of FCS. A certain fetuin-like substance in FCS might be responsible for the observed inhibition of virus replication.  相似文献   
62.

Background

Hydrocele is abnormal collection of serous fluid in the tunica vaginalis or a patent processus vaginalis. It is commonly encountered in our practice and often requires surgical treatment. However in our setting and in many underdeveloped countries, availability of general anaesthetic service is poor due to lack of trained personnel and equipment.

Objectives

To ascertain the practicability and acceptability of hydrocelectomy under sedation and local anaesthesia in Nigerian adults with hydrocele

Patients and Methods

A prospective study was carried out over a two year period on patients that had hydrocelectomy at the surgery unit of the Obafemi Awolowo University Teaching Hospitals Complex, Wesley Guild Hospital, Ilesa. Consecutive patients with diagnosis of hydrocele who consented had hydrocelectomy using intramuscular diazepam sedation and spermatic-cord block with 0.5% plane xylocaine and the scrotum infiltrated with same along the line of incision.

Results

Fifty adult patients were studied: age range 15–94 years. Eighty percent of the patients had unilateral hydrocele and the commonest type was vaginal hydrocele (94%). All patients had hydrocelectomy, 96% were under local anaesthesia while 4% were converted to general anaesthesia. All patients except one prefer to have future surgery under such local anaesthesia and sedation.

Conclusion

Hydrocelectomy under local anaesthesia and sedation is practicable and was tolerated and accepted by the adults patients studied.  相似文献   
63.
A temperature-sensitive mutant virus unable to replicate at 38 degrees C was recovered from passage 189 (IVpi-189) of Madin-Darby canine kidney cells infected persistently with influenza A. Immunofluorescent staining of the IVpi-189 virus-infected cells revealed disrupted transport of the matrix (M) 1 protein into the nucleus at non-permissive temperatures, resulting in retention of the nucleoprotein (NP) in the nucleus. Upon comparison with the parental influenza A E61-24-P15 strain used to establish persistent infection, amino acid exchanges were found in the M1 protein of IVpi-189 virus; arginine to glutamine at position 72 and threonine to alanine at position 139. When mice were inoculated intranasally with IVpi-189 virus, virus growth in the lungs was restrained and terminated rapidly. Prior intranasal inoculation with only a small dose of IVpi-189 virus induced humoral and cellular immune responses and protected mice against subsequent virulent virus challenge. These results indicate that IVpi-189 virus, an avirulent temperature-sensitive mutant, is a promising candidate for use as a live-attenuated vaccine.  相似文献   
64.
65.
Bilbey  JH; Muller  NL; Connell  DG; Luoma  AA; Nelems  B 《Radiology》1989,171(2):381-384
Diagnosis of the thoracic outlet syndrome is often difficult, particularly in patients without osseous abnormalities on plain radiographs. The radiographic and computed tomographic (CT) findings were reviewed from 27 patients with thoracic outlet syndrome and 21 normal subjects. The plain radiographs and CT scans were assessed by two independent observers without awareness of the clinical history. Fifteen patients with thoracic outlet syndrome had osseous abnormalities (anomalous cervical ribs; abnormally long, drooping C-7 transverse processes) identifiable on plain radiographs. CT did not provide further diagnostic information in the patients with abnormal radiographs. Eight of 12 patients (66%) with normal plain radiographs had abnormal findings on CT scans, consisting of impingement of the C-7 transverse process on the scalene triangle or anteromedial aspect of the middle scalene muscle. Only two of 21 control patients (9.5%) displayed this CT abnormality (P less than .01). CT may be useful in patients with symptoms suggestive of thoracic outlet syndrome and no osseous abnormalities on plain radiographs.  相似文献   
66.
OBJECTIVE: Assessment of haemodynamic effects of 250 ml hypertonic saline 7.5% (HS) perfusion in critically ill patients with severe sepsis or septic shock. STUDY DESIGN: Observational study. PATIENTS: Twelve mechanically ventilated patients with severe sepsis or septic shock requiring a pulmonary artery catheter and volume loading. INTERVENTION: Two hundred and fifty millilitres HS were given over 15 min. Were measured: heart rate (HR), mean arterial pressure (MAP) and pulmonary artery pressure (MPAP), pulmonary capillary wedge pressure (PCWP), right atrial pressure (RAP), cardiac index (CI), indexed systemic vascular resistance (ISVR), indexed pulmonary vascular resistance (IPVR), plasma sodium, chloride, protein and haemoglobin concentrations and arterial blood lactate. Studied parameters were assessed at baseline (T(0)) and 5 (T(0)) and 105 min (T(120)) after the end of HS infusion. RESULTS: MAP, HR and RAP were not altered. HS increased PAPM (25 +/- 5-30 +/- 6 mmHg), PCWP (13 +/- 3-18 +/- 4 mmHg) and CI (3.5 +/- 1.2-4.6 +/- 1.1 l/min per m(2)) at T(20) (P < 0.05). ISVR and IPVR were decreased at T(20). Protein and haemoglobin were decreased at T(20). Sodium and chloride were increased at T(20) (from 136 +/- 4 to 147 +/- 4 and from 110 +/- 6 to 123 +/- 6 mmol/l, respectively, P < 0.01) and T(120). CONCLUSION: In patients with severe sepsis or septic shock, 250 ml HS transiently (<120 min) increases CI and PCWP and induces an increase in sodium and chloride concentrations.  相似文献   
67.
Cardiac amyloidosis is a heterogeneous and challenging diagnostic disease with poor prognosis that is now being altered by introduction of new therapies. Echocardiography remains the first-line imaging tool, and when disease is suspected on echocardiography, cardiac magnetic resonance imaging and nuclear imaging play critical roles in the non-invasive diagnosis and evaluation of cardiac amyloidosis. Advances in multi-modality cardiac imaging allowing earlier diagnosis and initiation of novel therapies have significantly improved the outcomes in these patients. Cardiac imaging also plays important roles in the risk stratification of patients presenting with cardiac amyloidosis. In the current review, we provide a clinical and imaging focused update, and importantly outline the imaging protocols, diagnostic and prognostic utility of multimodality cardiac imaging in the assessment of cardiac amyloidosis.  相似文献   
68.

Purpose

We compared renal function outcomes among patients in the surveillance and intervention arms of the DISSRM registry.

Materials and methods

Patients were grouped into chronic kidney disease stages by estimated glomerular filtration rate range. Cases were considered up staged if a more advanced chronic kidney disease stage was entered during followup. Chronic kidney disease up staging-free survival was compared among groups using Kaplan-Meier analysis and paired comparisons log rank tests. Multivariate Cox regression identified independent predictors of chronic kidney disease up staging-free survival.

Results

A total of 162 patients met the study inclusion criteria, with 68 in the surveillance arm, 65 undergoing partial nephrectomy, 15 undergoing radical nephrectomy, and 14 undergoing cryoablation. Median tumor size was 2.2 cm. Mean estimated glomerular filtration rate change was significantly larger for radical nephrectomy vs. surveillance (?9.2 vs. ?0.5 ml/min/1.73 m2) and for radical vs. partial nephrectomy (?9.2 vs. ?1.9 ml/min/1.73 m2) (P = 0.001). No other groups differed significantly. On Kaplan-Meier analysis, patients undergoing radical nephrectomy had significantly worse chronic kidney disease up staging-free survival vs. those treated with partial nephrectomy (P = 0.029), surveillance (P = 0.007), and cryoablation (P = 0.019). No other groups differed significantly. On multivariate analysis, radical nephrectomy independently predicted poor chronic kidney disease up staging-free survival (odds ratio vs. surveillance 30.6, P = 0.001). Neither partial nephrectomy (P = 0.985) nor cryoablation (P = 0.976) predicted poor chronic kidney disease up staging-free survival relative to surveillance.

Conclusions

Patients in the surveillance arm had superior estimated glomerular filtration rate preservation compared to those in the radical nephrectomy but not the partial nephrectomy arm. In certain patients with small renal masses, surveillance and partial nephrectomy may offer comparable renal functional outcomes. This could be partly attributable to a modest estimated glomerular filtration rate decrease associated with surveillance itself. A thorough understanding of the renal functional impacts of treatment modalities is critical in the management of small renal masses.  相似文献   
69.
70.
The neuropeptide Y (NPY) is widely expressed in the central nervous system and has been shown to stimulate neurogenesis in the hippocampus and the olfactory epithelium. Here, we demonstrate that intracerebroventricular injection of NPY stimulates proliferation of neural precursors in the mice subventricular zone (SVZ), one the most neurogenic areas of the brain. Newly generated neuroblasts migrate through the rostral migratory stream to the olfactory bulb and also directly to the striatum, as evidenced by BrdU labelling and cell phenotyping. Using knock-out mice, specific NPY receptor agonists and antagonists, we report that this neuroproliferative effect is mediated by the Y1 receptor subtype that we found to be highly expressed in the SVZ both at the mRNA and protein levels. Our data suggest that stimulating endogenous SVZ neural stem cells by NPY may be of a potential interest in cell replacement based therapies of neurodegenerative diseases affecting the striatum such as Huntington's disease.  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