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   2234篇
  免费   130篇
  国内免费   13篇
耳鼻咽喉   30篇
儿科学   102篇
妇产科学   17篇
基础医学   394篇
口腔科学   56篇
临床医学   184篇
内科学   493篇
皮肤病学   16篇
神经病学   179篇
特种医学   154篇
外科学   265篇
综合类   12篇
一般理论   1篇
预防医学   132篇
眼科学   24篇
药学   89篇
中国医学   3篇
肿瘤学   226篇
  2023年   12篇
  2022年   20篇
  2021年   37篇
  2020年   20篇
  2019年   38篇
  2018年   44篇
  2017年   37篇
  2016年   40篇
  2015年   34篇
  2014年   59篇
  2013年   82篇
  2012年   126篇
  2011年   112篇
  2010年   77篇
  2009年   70篇
  2008年   94篇
  2007年   97篇
  2006年   100篇
  2005年   97篇
  2004年   88篇
  2003年   85篇
  2002年   68篇
  2001年   89篇
  2000年   60篇
  1999年   64篇
  1998年   35篇
  1997年   37篇
  1996年   41篇
  1995年   29篇
  1994年   44篇
  1993年   26篇
  1992年   23篇
  1991年   27篇
  1990年   34篇
  1989年   35篇
  1988年   29篇
  1987年   39篇
  1986年   22篇
  1985年   15篇
  1983年   13篇
  1982年   12篇
  1981年   11篇
  1980年   11篇
  1979年   16篇
  1976年   10篇
  1975年   11篇
  1974年   13篇
  1970年   10篇
  1932年   10篇
  1931年   20篇
排序方式: 共有2377条查询结果,搜索用时 15 毫秒
31.
A polyclonal antibody-based, group-specific, indirect, sandwich ELISA (S-ELISA) for the detection of equine encephalosis virus (EEV) antigen was developed. Purified EEV particles were titrated in the S-ELISA and the limit of detection was determined to be approximately 9.0 ng of antigen/ml (0.45 ng/well). Positive S-ELISA reactions were recorded with seven serologically distinct EEV serotypes. No cross-reactions were recorded with other arboviruses including African horse sickness virus (AHSV) serotypes 1-9, bluetongue serotypes 1-24, epizootic haemorrhagic disease serotypes 1-8 and isolate 318, and selected isolates of Palyam, Eubenangee, Corriparta, Warrego, Akabane and bovine ephemeral fever viruses. The assay proved to be sensitive and specific for the rapid detection of EEV in cell cultures and in homogenated suckling mouse brain (MB). The data generated in this study suggest that the ELISA will be valuable for epidemiological studies of EE and will assist in making a reliable differential diagnosis between EEV and AHSV infections.  相似文献   
32.
Clonal chromosome abnormalities were found in short-term cultures from two epithelial skin tumors, a basal cell papilloma and a keratoacanthoma. The three-way translocation t(2;6;11)(q21;q27;p13) was the sole clonal rearrangement in the basal cell papilloma. The karyotype of the keratoacanthoma was more complex: 46,XX,der(2)(2pter----2p13::2p11----cen----2q37: :5q33----5qter),der(2) (:2p13----cen----2q37::6q23----6qter),der(5)t(2; 7;5)(q37;q11;q33),der(6) (6pter----cen----6q23::2p13----2pter),der(7)t(2; 7;5)(q37;q11;q33), del(13)(q11q14). In addition, several nonclonal structural changes were seen in both tumors.  相似文献   
33.
Phenotypically, ganciclovir-resistant human cytomegalovirus strains could be selected by aciclovir as effectively as by ganciclovir in vitro. Three clinical human cytomegalovirus isolates with different sensitivities against ganciclovir, aciclovir, foscarnet, and cidofovir, but without any mutation in the viral UL97 protein known to confer ganciclovir resistance, were propagated each in duplicate in the presence of ganciclovir or aciclovir. After drug selection, all 12 strains were less susceptible to ganciclovir (increase of 50% focus reduction dose between 2.1- and 31.5-fold) but were still sensitive to foscarnet and cidofovir; 7/12 exhibited a ganciclovir-resistant phenotype with a 50% focus reduction dose >30 microM, and in 6 out of these typical mutations in the UL97 coding region could be found by genotyping. All four strains selected from one isolate carried the identical UL97 mutation at amino acid position 460 (methionine to valine). The decreased sensitivity to ganciclovir and aciclovir in the other strains could neither be attributed to known UL97 mutations nor to mutations in the viral polymerase (UL54), which have been reported to induce resistance.  相似文献   
34.
A new high yield 123I radioiodination (97%), based on the Cu(I) assisted isotopic exchange in an ethanol water mixture, of 15(p-I-phenyl)-9 methyl pentadecanoic acid, a potential myocardial tracer, is proposed. The method allows a true kit preparation of radioiodinated phenyl fatty acids for a substrate concentration of ±10-6 moles. High specific activities (>0.1 mCi/g) can be obtained when coupling the labelling method to HPLC purification with an overall radiochemical yield of 75%.  相似文献   
35.
To validate anecdotal evidence on scabies infestations, we analyzed inpatient and outpatient claims data in Germany. Scabies diagnoses increased 9-fold and treatment failure 4-fold during 2009–2018, driven mainly by persons 15–24 years of age. Prevention and control in young adults appear key because of these persons’ high mobility and social connectivity.  相似文献   
36.
37.
Ten liposarcomas were analyzed cytogenetically after short-term culturing. Eight tumors had a t(12;16) (q13;p11) and two tumors had complex translocations involving chromosomes 7, 12, and 16 and 2, 9, 12, 16 and 20, respectively. Among the secondary aberrations seen in five tumors, +8 was found in two tumors and i(7)(q10) in four tumors. Trisomy 8 has previously been described as a nonrandom secondary aberration in myxoid liposarcoma, but i(7q) has only been reported in a single case before. All recurrent chromosome aberrations reported in liposarcomas with recombination between 12q13 and 16p11 (42 cases) were surveyed and compared with their frequencies in liposarcomas without this recombination (33 cases). Trisomy 5 and 8 were found in both tumor groups, whereas +19, t(3;15)(p23;q15), del(6)(q21), i(7q), and rearrangements of 1p11 and 2q35 were found exclusively in tumors with 12q13 and 16p11 aberrations.  相似文献   
38.
The case of a 54-year-old woman with metastatic follicular thyroid cancer and undetectable serum thyroglobulin is presented. Many years after the patient had a subtotal thyroidectomy for a large goiter that had no clear evidence of malignancy, metastatic bone disease developed. When the bone metastases were detected and during the follow-up period, serum thyroglobulin values remained undetectable, but radioiodine uptake in the metastases was abundant. This case indicates that the combination of 1-131 scintigraphy and serum thyroglobulin values is superior to the measurement of serum thyroglobulin alone in detecting well-differentiated, metastatic thyroid cancer.  相似文献   
39.
The authors report a series of 23 patients with central neuropathic pain who were treated with the recently developed technique of precentral cortex stimulation (PCS). Of the 20 patients with a follow-up of more than 1 year (mean of 23 months) 25% had an excellent, 35% a good and 15% a fair relief of pain. In 25% the method failed. On the basis of these findings and the literature data (127 reported cases), the authors advocate PCS in patients with severe and medically refractory poststroke pain.  相似文献   
40.
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