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   4777篇
  免费   243篇
  国内免费   35篇
耳鼻咽喉   72篇
儿科学   99篇
妇产科学   29篇
基础医学   543篇
口腔科学   62篇
临床医学   386篇
内科学   1741篇
皮肤病学   180篇
神经病学   268篇
特种医学   161篇
外科学   599篇
综合类   10篇
预防医学   163篇
眼科学   34篇
药学   183篇
中国医学   1篇
肿瘤学   524篇
  2023年   22篇
  2022年   60篇
  2021年   115篇
  2020年   67篇
  2019年   86篇
  2018年   97篇
  2017年   75篇
  2016年   82篇
  2015年   104篇
  2014年   122篇
  2013年   156篇
  2012年   269篇
  2011年   242篇
  2010年   119篇
  2009年   98篇
  2008年   158篇
  2007年   175篇
  2006年   185篇
  2005年   196篇
  2004年   179篇
  2003年   201篇
  2002年   194篇
  2001年   165篇
  2000年   153篇
  1999年   151篇
  1998年   60篇
  1997年   46篇
  1996年   37篇
  1995年   24篇
  1994年   38篇
  1993年   35篇
  1992年   114篇
  1991年   109篇
  1990年   109篇
  1989年   115篇
  1988年   83篇
  1987年   89篇
  1986年   97篇
  1985年   96篇
  1984年   75篇
  1983年   76篇
  1982年   29篇
  1980年   24篇
  1979年   45篇
  1978年   31篇
  1977年   22篇
  1976年   21篇
  1974年   36篇
  1973年   21篇
  1972年   27篇
排序方式: 共有5055条查询结果,搜索用时 15 毫秒
31.
The cases of 29 patients with cervical myelopathy, who had been treated by anterior spine fusion, were reviewed. The relationship between pre- and postoperative magnetic resonance (MR) images was investigated with special reference to increased signal intensity in the spinal cord on the T2-weighted images and the relevance of this finding to clinical conditions. Preoperatively, there were areas of increased signal intensity in 12 patients whereas there were no areas of increased signal intensity in the other 17. The lesions were not clearly demonstrated on T1-weighted images. The pre- and postoperative clinical condition of the patients whose preoperative MR images showed areas of increased signal intensity in the spinal cord on T2-weighted images was worse than that of the patients who did not have areas of increased signal intensity. Of the 12 patients with regions of increased signal intensity preoperatively, five showed decreased signal intensity postoperatively compared to the preoperative levels and seven had no change. The postoperative recovery of the five patients who showed decreased signal intensity postoperatively was better than that of the seven patients who exhibited no change. The areas of increased MR signal in the spinal cord might be due to edema, cord gliosis, demyelination, or microcavities.  相似文献   
32.
33.
A case of small fibrolamellar hepatocellular carcinoma (HCC) coexistent with a HCC of common type is herein reported. A 56-year-old man was diagnosed as having multi-nodular type HCC with liver cirrhosis. The serum alpha-fetoprotein (AFP) level was slightly increased. The patient underwent a partial caudate lobectomy and lateral segmentectomy. Histologically, both resected tumors were small HCCs measuring less than 2 cm in diameter. One was a fibrolamellar type located in the caudate lobe, while the other was the common type in the lateral segment of the liver. Positive immunohistochemical staining for AFP was observed in the tumor cells of the HCC of common type but was not observed in the fibrolamellar HCC. We also reviewed previously reported cases of fibrolamellar HCC in Japan, and discussed the clinicopathologic implications of this disease.  相似文献   
34.
This study focuses on a possible role of intercellular adhesion molecule-1 (ICAM-1) in interstitial pulmonary diseases. We determined a soluble form of ICAM-1 in serum and bronchoalveolar lavage fluid (BALF) using ELISA in patients with usual interstitial pneumonia (UIP), bronchiolitis obliterance organizing pneumonia (BOOP), or nonspecific interstitial pneumonia (NSIP). In addition, we investigated the expression of ICAM-1 in the lung tissues of these patients by means of immunohistochemical staining. Serum levels of soluble ICAM-1 were significantly higher in patients with UIP or NSIP than in healthy subjects, and were also high in patients with BOOP. The soluble ICAM-1 in BALF tended to be higher in patients with UIP, BOOP, or NSIP than in normal subjects. A significant correlation was seen between soluble levels of ICAM-1 in serum and BALF. In the immunostaining of ICAM-1 of the lung tissues, ICAM-1 expression was more pronounced in patients with UIP than in those with BOOP or NSIP. The increased expression of ICAM-1 was seen in type II alveolar epithelium and vascular endothelium in patients with interstitial pneumonia. A positive correlation was observed between the degree of ICAM-1 expression in the lung tissues and the BALF levels of soluble ICAM-1. The expression of ICAM-1 in type II alveolar epithelium suggests that ICAM-1 plays a specific role in the fibrotic process of the lung, and that the measurement of soluble ICAM-1 in sera and BALF could be a useful marker for evaluating the progression of fibrosis.  相似文献   
35.
36.
37.
To determine the transacting genetic factors of NZW contributing to the development of autoimmune disease in (NZB X NZW)F1 (B/W F1) mice, we examined the relationship between the T cell receptor beta chain gene deletion and the severity of autoimmune manifestations in 76 B/W F1 X NZB backcross mice. Very high association between the T cell receptor beta chain gene deletion and the development of autoimmune manifestations including the production of IgG anti-DNA antibodies and circulating retroviral gp70 immune complexes was observed, indicating that a defect in the NZW T cell receptor beta chain gene or a locus closely linked to it contributes to the autoantibody formation in B/W F1.  相似文献   
38.
39.
A rounding cell-forming--GC strain, which is a variant of a syncytial giant cell-forming herpes simplex virus (+GC Miyama strain), was highly attenuated for Swiss, BALB/c nu/nu, and nu/+ mice, whereas +GC was highly virulent to all the mice tested. +GC and -GC were antigenically indistinguishable from each other by cross-neutralization and cross-immunization. Immunosuppression induced by cyclophosphamide converted the nonlethal -GC infection of mice into a fatal infection. -GC replication in tissue culture was more effectively suppressed by spleen cells immunized with either +GC or -GC than was the +GC replication. -GC replication was also inhibited more effectively by antibody or the antibody-dependent cell-mediated system than was the +GC replication. -GC is highly sensitive to mouse interferon, but +GC was relatively resistant. These findings indicate that attenuation of this avirulent -GC strain may be due to a high susceptibility of its replication to humoral and cell-mediated defense factors. The probable roles of each defense factor in recovery from the infection with virulent and attenuated herpes simplex virus are also discussed.  相似文献   
40.
We evaluated the performances of a ligase chain reaction (LCR)-based assay and two enzyme immunoassays (Chlamydiazyme and IDEIA) in the detection of Chlamydia trachomatis in urine specimens. We compared the results of testing urine specimens by these assays with those of urethral swab culture by examining samples from 131 men with nongonococcal urethritis. Discrepant results were analyzed by testing urethral swab specimens for C. trachomatis by a PCR-based assay. After the resolution of discrepant results, the sensitivity of urethral swab culture was 85.3%, whereas those of the LCR assay, Chlamydiazyme, and IDEIA with urine specimens were 94.1, 82.4, and 94.1%, respectively. The LCR assay and IDEIA were more sensitive than was urethral swab culture. In addition, the LCR assay, with a sensitivity equal to that of IDEIA, was more specific. Overall, the LCR assay proved to be superior to the enzyme immunoassays in detecting C. trachomatis in urine specimens. Testing urine specimens by LCR assay should be a helpful alternative method for diagnosing C. trachomatis urethral infection in men with nongonococcal urethritis.  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