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   225篇
  免费   12篇
  国内免费   19篇
儿科学   11篇
妇产科学   2篇
基础医学   22篇
口腔科学   8篇
临床医学   21篇
内科学   34篇
皮肤病学   7篇
神经病学   6篇
特种医学   41篇
外科学   20篇
综合类   20篇
预防医学   9篇
药学   41篇
中国医学   1篇
肿瘤学   13篇
  2023年   1篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2018年   3篇
  2017年   3篇
  2016年   3篇
  2015年   9篇
  2014年   10篇
  2013年   12篇
  2012年   5篇
  2011年   4篇
  2010年   12篇
  2009年   12篇
  2008年   6篇
  2007年   14篇
  2006年   16篇
  2005年   7篇
  2004年   4篇
  2003年   6篇
  2002年   2篇
  2001年   7篇
  2000年   4篇
  1999年   5篇
  1998年   19篇
  1997年   15篇
  1996年   10篇
  1995年   6篇
  1994年   11篇
  1993年   10篇
  1992年   1篇
  1991年   3篇
  1990年   1篇
  1989年   5篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1985年   4篇
  1984年   4篇
  1983年   5篇
  1982年   3篇
  1981年   1篇
  1980年   1篇
  1977年   3篇
排序方式: 共有256条查询结果,搜索用时 15 毫秒
91.
To prospectively compare the feasibility, safety and diagnostic role of carbon dioxide (CO2) digital subtraction angiography (DSA) using a ‘home made’ delivery system with iodinated contrast medium (ICM) DSA in the evaluation of peripheral arterial occlusive diseases (PAOD) of lower limbs. Twenty‐one patients (27 limbs; all men; mean age, 47.6 years) who presented with PAOD of lower limbs underwent DSA using both intra‐arterial CO2 and ICM. Conventional ICM DSA was performed first and used as gold standard. Carbon dioxide was then injected by hand using a locally improvised home made plastic bag delivery system. Patient tolerance was assessed subjectively. Arteries from aortic bifurcation to the ankle were independently evaluated by two radiologists and graded for stenosis using a five‐point scale. For each patient, the quality of CO2 DSA images were compared with the corresponding images of ICM DSA and an overall grade of ‘good’, ‘acceptable’ or ‘poor’ was assigned. Cohen’s kappa coefficient was used to determine inter‐observer agreement. Carbon dioxide opacified 86.2% (188/195) of major arteries and depicted stenosis adequately in 84.5% (191/226) of arterial segments. A good or acceptable image quality of CO2 DSA was obtained in over 95% of patients. Infrapopliteal arteries were inadequately visualized. Mild pain was seen in six (28.6%) patients with both contrast agents; one patient developed severe pain during CO2 DSA. Inter‐observer agreement was good (k > 0.75) at 70% of the segments. Administration of CO2 into lower limb arteries is well tolerated. Carbon dioxide DSA using the locally improvised home made delivery system is a feasible and safe alternative to ICM DSA in the evaluation of PAOD. It provides adequate imaging of arteries of lower extremities except infrapopliteal segments.  相似文献   
92.
目的:考察不同辅料的国产碘海醇(Iohexol)注射液稳定性的影响。方法:测定高温灭菌前后6组不同辅料的碘海醇注射液PH、碘离子浓度、含量变化。结果与结论:同时含三羟甲基氨基甲烷(Tris,1.2mg/ml)、乙二胺四乙酸二钠钙(EDTA-Na2Ca,0.1mg/ml)2种辅料时,碘海醇注射液最稳定。  相似文献   
93.
94.
Glick  SN; Teplick  SK 《Radiology》1985,154(2):313-317
A diffuse granular mucosal pattern, produced by a reticular network of radiolucent foci 0.5 to 1 mm in diameter, was identified in 39 out of 46 consecutive patients with Crohn disease of the small intestine. Resected specimens demonstrated that this pattern represented wide, blunted villi with lymphocytic infiltration. Such a pattern was the only evidence of small bowel involvement in 17 cases. In 3 patients with the commonly recognized lesions, separate regions of diffuse granularity were seen. No such pattern was detected in normal patients. Demonstration of diffuse granularity may contribute to the diagnosis and management of Crohn disease.  相似文献   
95.
96.
用高效液相色谱法对5-乙基-5-对氟苯甲酰丙基巴比妥酸在家兔体内的代谢物进行了分离,用二极管阵列检测器测定了原药及代谢物紫外图谱,得出代谢物的紫外吸收性质;同时测试了原药及代谢物的质谱,推测出代谢物的可能结构,并用化学方法合成了代谢物对照品,通过核磁和质谱的测定进一步确证了结构。  相似文献   
97.
用离体大鼠肝脏灌流法,研究了抗痫灵在肝脏灌流过程中的代谢规律。用高效液相色谱法由灌流液中分离、制备得到了两种代谢物,经紫外吸收光谱与质谱鉴定,确定代谢物的结构为3,4-次甲基二氧桂皮酰羟基哌啶及阿魏酰哌啶,后者经化学合成得到了进一步的确证。本文还研究了肝循环过程中抗痫灵的代谢动力学,揭示了大部份抗痫灵以原形结合贮存于肝脏中。  相似文献   
98.
Exosomes (EXO) derived from dendritic cells (DC) and tumor cells have been used to stimulate antitumor immune responses in animal models and in clinical trials. However, there has been no side-by-side comparison of the stimulatory efficiency of the antitumor immune responses induced by these two commonly used EXO vaccines. In this study, we selected to study the phenotype characteristics of EXO derived from a transfected EG7 tumor cells expressing ovalbumin (OVA) and OVA-pulsed DC by flow cytometry. We compared the stimulatory effect in induction of OVA-specific immune responses between these two types of EXO. We found that OVA protein-pulsed DCovA-derived EXO (EXODC) can more efficiently stimulate naive OVA-specific CD8+ T cell proliferation and differentiation into cytotoxic T lymphocytes in vivo, and induce more efficient antitumor immunity than EG7 tumor cell-derived EXO (EXOEG7). In addition, we elucidated the important role of the host DC in EXO vaccines that the stimulatory effect of EXO is delivered to T cell responses by the host DC. Therefore, DC-derived EXO may represent a more effective EXO-based vaccine in induction of antitumor immunity.  相似文献   
99.
A competitive protein binding radioassay kit for serum vitamin B12 has been assessed. Precision, linearity, sensitivity, and specificity have been found to be satisfactory. Falsely-normal assay results in patients with vitamin B12 deficiency have not been observed.  相似文献   
100.
Vascular endothelial growth factor (VEGF) is a cytokine that induces angiogenesis. Angiogenesis is a prominent histologic component of the luteinization process. Luteinization is also characterized by granulosa cell progesterone secretion in response to the luteinizing hormone (LH) surge. Local VEGF production in human pre-ovulatory follicles, induced by LH, was postulated to be a luteinization mediator in women. To investigate this hypothesis, serum and fluid from the dominant follicle of 31 healthy regularly cycling multiparous women undergoing laparoscopic sterilization were obtained. VEGF was measured by enzyme- linked immunosorbent assay, and LH and progesterone were measured by radioimmunoassay. Follicle aspiration was performed at a median of 13 days from the last menstrual period (range 11-17 days). The median pre- ovulatory follicle diameter was 16 mm (range 11-23 mm). Follicle fluid VEGF concentrations (mean 6900 pg/ml, range 1200-17 100 pg/ml) were correlated positively with follicle fluid progesterone concentrations (mean 10 176 nmol/l, range 636-66780 nmol/l, r=0.62, P=0.002). This correlation was even tighter (r=0.87, P < 0.0001) when only samples from the 22 women in the earliest stages of follicle luteinization were considered. In these women serum LH concentrations were also correlated with follicle fluid VEGF concentrations (r=0.51, P=0.02). Our findings demonstrate the close dynamic relationship between VEGF production and early luteinization in human follicles during normal non-stimulated cycles.   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