全文获取类型
收费全文 | 820篇 |
免费 | 31篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 38篇 |
妇产科学 | 3篇 |
基础医学 | 75篇 |
口腔科学 | 11篇 |
临床医学 | 115篇 |
内科学 | 223篇 |
皮肤病学 | 20篇 |
神经病学 | 26篇 |
特种医学 | 144篇 |
外科学 | 34篇 |
综合类 | 24篇 |
一般理论 | 1篇 |
预防医学 | 9篇 |
眼科学 | 5篇 |
药学 | 102篇 |
中国医学 | 3篇 |
肿瘤学 | 63篇 |
出版年
2023年 | 2篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 4篇 |
2015年 | 23篇 |
2014年 | 17篇 |
2013年 | 22篇 |
2012年 | 9篇 |
2011年 | 15篇 |
2010年 | 37篇 |
2009年 | 26篇 |
2008年 | 17篇 |
2007年 | 50篇 |
2006年 | 14篇 |
2005年 | 15篇 |
2004年 | 12篇 |
2003年 | 17篇 |
2002年 | 20篇 |
2001年 | 30篇 |
2000年 | 13篇 |
1999年 | 15篇 |
1998年 | 47篇 |
1997年 | 52篇 |
1996年 | 60篇 |
1995年 | 35篇 |
1994年 | 33篇 |
1993年 | 23篇 |
1992年 | 14篇 |
1991年 | 19篇 |
1990年 | 11篇 |
1989年 | 37篇 |
1988年 | 29篇 |
1987年 | 23篇 |
1986年 | 21篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 7篇 |
1982年 | 15篇 |
1981年 | 11篇 |
1980年 | 15篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1931年 | 1篇 |
1925年 | 1篇 |
排序方式: 共有898条查询结果,搜索用时 31 毫秒
61.
肾康片质量标准的研究 总被引:4,自引:0,他引:4
目的:研究肾康片的质量标准并控制该制剂的质量。方法:用薄层色谱法鉴别了肾康片中的黄芪,山茱萸,桑寄生及丹参,用薄层色谱法限量检查屯该制剂中的乌头碱,用双波长薄层扫描法测定了该制剂中黄芪甲苷的含量。结果:乌头碱限量符合中国药典测定,黄芪甲苷的平均回收率为97.5%,其RSD为1.43%。结论:本文的结果显示出这些方法可用于控制该制剂的质量,方法灵敏,简便,专属,准确。 相似文献
62.
A total of 68 major complications of cervical myelography were reported by 220 neuroradiologists in a mail survey. Two-thirds of the complications were attributed to cervical spine hyperextension and one-third to lateral C1-2 puncture. Narrow sagittal diameter of the spinal canal and severe cervical spondylosis were frequent contributing factors to hyperextension injury of the cervical spinal cord. Clinical and radiographic premyelography screening is suggested, with magnetic resonance imaging performed first in patients with spinal canal stenosis, severe spondylosis, and/or myelopathy of any cause. Neck extension should be minimal during myelography. All C1-2 punctures should be monitored with lateral fluoroscopy for accurate needle positioning and prevention of contrast medium injection into the spinal cord. 相似文献
63.
64.
The Nb rat prostatic adenocarcinoma model has served as an animal model for testing various chemotherapeutic agents. Herein this preliminary report, the tumor Nb PRST-1 Ca was evaluated in 25 animals with testosterone, dihydrotestosterone, orchiectomized and control treatments. Tumor growth curves were determined and show a significant difference on day 13 (T-test) between the control group and treatment groups. Metastases were found in the lungs of all animals and a remarkable rounding of the liver was noted in the androgen treatment groups. 相似文献
65.
RS de Vreeze D de Jong IH Tielen HJ Ruijter PM Nederlof RL Haas F van Coevorden 《Modern pathology》2009,22(2):223-231
Almost all primary retroperitoneal liposarcomas can be classified as well-/dedifferentiated liposarcoma. Rarely, however, primary retroperitoneal liposarcoma is classified as myxoid/round cell liposarcoma, based on the presence of myxoid areas and vascular crow's feet pattern, which has resulted in a debate on the classification of liposarcoma in the retroperitoneum. Genetically, myxoid/round cell liposarcoma and well-/dedifferentiated liposarcoma are different diseases. Myxoid/round cell liposarcoma is characterized by a translocation causing FUS-CHOP or EWSR1-CHOP fusion, whereas well-/dedifferentiated liposarcoma is characterized by an amplification of the 12q13-15 region, including MDM2 and CDK4 genes. As myxoid/round cell liposarcoma is highly radio- and chemosensitive, differentiation between subtypes is important to optimize treatment. We studied whether primary retroperitoneal liposarcomas diagnosed as myxoid/round cell liposarcoma represent molecularly true myxoid/round cell liposarcoma or are histopathological mimics and represent well-/dedifferentiated liposarcoma. Primary retroperitoneal myxoid/round cell liposarcoma (n=16) were compared to primary extremity myxoid/round cell liposarcoma (n=20). Histopathological and immunohistochemical features were studied. Amplification status of the 12q13-15 region was studied using a multiplex ligation-dependent probe amplification analysis, and FUS-CHOP or EWS-CHOP translocations were studied using RT-PCR. In primary retroperitoneal myxoid/round cell liposarcoma, MDM2 and CDK4 staining was both positive in 12 of 15 cases. In primary extremity myxoid/round cell liposarcoma, MDM2 was negative in 18/20 and CDK4 was negative in all cases. Multiplex ligation-dependent probe amplification showed the amplification of 12q13-15 region in 16/16 primary retroperitoneal myxoid/round cell liposarcomas and in 1/20 primary extremity myxoid/round cell liposarcomas. Translocation was present in all (18/18) primary extremity myxoid/round cell liposarcomas, but absent in all primary retroperitoneal myxoid/round cell liposarcomas. On the basis of immunohistochemical and molecular characteristics, apparent primary retroperitoneal myxoid/round cell liposarcoma can be recognized as well-/dedifferentiated liposarcoma with morphological features mimicking myxoid/round cell liposarcoma. In these cases, treatment should probably be specifically designed as for well-/dedifferentiated liposarcoma. Moreover, finding of myxoid/round cell liposarcoma translocations in a retroperitoneal localization is highly suggestive of metastasis and should prompt search for a primary localization outside the retroperitoneum. 相似文献
66.
目的:探讨谷氨酸对脑组织即早基因表达的影响以及醋酸锌对谷氨酸诱导c-fos和c-jun过度表达的拮抗作用。方法:体外小鼠海马脑片培养;在培养基中加入200μmol/L的谷氨酸(或同时加入谷氨酸和醋酸锌),作用0.5,1,2,3h,然后进行RT-PCR实验,检测c-fos和c-jun的表达变化。结果:200μmol/L谷氨酸处理的脑片中,1-2h期间c-fos的表达升高,当谷氨酸与100μmol/L醋酸锌共同处理脑片时,1-3h期间c-fos表达基本恢复正常;200μmol/L谷氨酸作用下,脑片c-jun表达水平从0.5h起即明显升高,谷氨酸与醋酸锌共同作用时,可见c-jun基因在各检测时段表达基本接近正常。结论:谷氨酸可引起c-fos及c-jun的过度表达,锌离子可拮抗谷氨酸诱导的c-fos和c-jun过度表达作用,使二基因表达恢复正常。 相似文献
67.
Ultraviolet irradiation of blood prevents transfusion-induced sensitization and marrow graft rejection in dogs 总被引:1,自引:1,他引:0
In a canine model using DLA-identical littermate pairs, we have shown that a regimen of three transfusions of donor blood given 24, 17, and 10 days before transplant uniformly leads to marrow graft rejection, presumably due to sensitization to minor (non-DLA) histocompatibility antigens. Untransfused dogs uniformly achieve sustained engraftment. In the present study, we investigated whether the exposure of blood to ultraviolet (UV) light (220-300 nm) prior to transfusion prevented sensitization of the recipient and allowed for successful marrow engraftment. Ten dogs were each given three pretransplant transfusions from the marrow donor. Each transfusion consisted of 50 mL of whole blood exposed in vitro to UV light for a total of 1.35 J/cm2. All ten dogs achieved engraftment. In contrast, all four dogs that had received sham-exposed transfusions rejected their grafts. In vitro studies revealed that although cell viability was not affected, leukocytes contained in UV-exposed blood were unable to function as stimulator cells in mixed leukocyte cultures or as accessory cells in mitogen- stimulated cultures. These data are consistent with the hypothesis that accessory cells are involved in transfusion-induced sensitization. We conclude that in vitro exposure of blood to UV light before transfusion prevents sensitization and allows for subsequent marrow engraftment. 相似文献
68.
69.
C Ziebold R von Kries A Siedler HJ Schmitt 《Acta paediatrica (Oslo, Norway : 1992)》2000,89(S435):17-21
Recently published and as yet unpublished data allow a reasonable estimate of the annual burden of pneumococcal disease in Germany. At least 277000 episodes of otitis media and at least 2000 episodes of sinusitis occur in children under the age of 5 y. Pneumococcal meningitis was found in 200 children under the age of 16 y; the estimate for all age groups ranges from 450 to 1100 cases. Of approximately 150000 cases of ambulatory pneumococcal pneumonia, at least 63 000–105000 patients are hospitalized each year.
Conclusion: Further studies of pneumococcal epidemiology in Germany are needed, and continued surveillance will be necessary for a better understanding of the overall burden of pneumococcal disease in children as well as adults. 相似文献
Conclusion: Further studies of pneumococcal epidemiology in Germany are needed, and continued surveillance will be necessary for a better understanding of the overall burden of pneumococcal disease in children as well as adults. 相似文献
70.
JH Burridge DE Wood HJ Hermens GE Voerman GR Johnson F. Van Wijck T. Platz M. Gregoric R. Hitchcock AD Pandyan 《Disability and rehabilitation》2005,27(1):69-80
Purpose: To discuss the measurement of spasticity in the clinical and research environments, make recommendations based on the SPASM reviews of biomechanical, neurophysiological and clinical methods of measuring spasticity and indicate future developments of measurement tools. Method: Using the results of the systematic reviews of the biomechanical, neurophysiological and clinical approaches, methods were evaluated across three dimensions: (1) validity, reliability and sensitivity to change; (2) practical quality such as ease of use and (3) qualities specific to the measurement of spasticity, for example ability to be applied to different muscle groups. Methods were considered in terms of applicability to research and clinical applications. Results: A hierarchy of measurement approaches was identified from highly controlled and more objective (but unrelated to function) to ecologically valid, but less objective and subject to contamination from other variables. The lack of a precise definition of spasticity may account for the problem of developing a valid, reliable and sensitive method of measurement. The reviews have identified that some tests measure spasticity per se, some phenomena associated with spasticity or consequential to it and others the effect of spasticity on activity and participation and independence. Conclusions: Methods appropriate for use in research, particularly into the mechanism of spasticity did not satisfy the needs of the clinician and the need for an objective but clinically applicable tool was identified. A clinical assessment may need to generate more than one 'value' and should include evaluation of other components of the upper motor neurone syndrome. There is therefore a need for standardized protocols for 'best practice' in application of spasticity measurement tools and scales. 相似文献