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   927篇
  免费   51篇
  国内免费   2篇
耳鼻咽喉   1篇
儿科学   46篇
妇产科学   8篇
基础医学   125篇
口腔科学   7篇
临床医学   65篇
内科学   239篇
皮肤病学   133篇
神经病学   120篇
特种医学   10篇
外科学   85篇
综合类   2篇
预防医学   27篇
眼科学   13篇
药学   25篇
肿瘤学   74篇
  2022年   13篇
  2021年   14篇
  2020年   12篇
  2019年   9篇
  2018年   16篇
  2017年   9篇
  2016年   17篇
  2015年   17篇
  2014年   15篇
  2013年   32篇
  2012年   54篇
  2011年   57篇
  2010年   28篇
  2009年   31篇
  2008年   50篇
  2007年   57篇
  2006年   48篇
  2005年   44篇
  2004年   42篇
  2003年   41篇
  2002年   42篇
  2001年   16篇
  2000年   25篇
  1999年   23篇
  1998年   21篇
  1997年   6篇
  1996年   12篇
  1995年   9篇
  1994年   15篇
  1993年   12篇
  1992年   17篇
  1991年   21篇
  1990年   14篇
  1989年   15篇
  1988年   15篇
  1987年   15篇
  1986年   10篇
  1985年   13篇
  1984年   4篇
  1983年   11篇
  1982年   7篇
  1981年   6篇
  1980年   4篇
  1979年   5篇
  1976年   3篇
  1975年   3篇
  1973年   4篇
  1971年   3篇
  1969年   3篇
  1966年   3篇
排序方式: 共有980条查询结果,搜索用时 15 毫秒
1.
A prognosis of patients with a curative resected advanced cancer of the lower gastric region was worse than that of the other region of the stomach. The 5 year survival rate was only 47.3%. One of the main reasons was that a rate of lymph node recurrence was higher. In this point of view, we studied on lymphatic flow of the lower gastric region using an activated carbon particle (CH40). Lymph nodes were stained black soon after the injection of CH40 into the lower gastric wall at laparotomy. The black stained rate of an each regional lymph node was as follows. 3. 58%, 4. 17%, 5. 50%, 6. 25%, 1. 21%, 7. 58%, 8. 83%, 9. 58%, 11. 17% and 12. 33% in case of injection into the greater curvature and and 4. 31%, 6. 100%, 8. 25%, 9. 25%, 14V and 56% in case of injection into the lesser curvature. The stained rate was relatively high in 12 and 14V lymph node which we had not routinely dissected. The rates of lymph nodes stained black were related to those of cancer metastasis. The results suggest that lymphadenectomy of 12 for the cancer at the lesser curvature and that of 14V for the cancer at the greater curvature might make a prognosis of lower gastric cancer better.  相似文献   
2.
A nationwide survey of transient hyperammonemia in newborns was carried out in Japan. A total of 18 patients, consisting of 12 male and 6 female infants, were reported from 11 facilities. These neonates exhibited hyperammonemia with plasma ammonia levels in the range from 124 to 6256 micrograms/dl. Four newborn infants of the 18 died in the neonatal period, and an additional one died in the early infancy. Among the 13 infants who were alive at the time of this survey, 6 had neurological sequelae, including mental retardation, spastic quadriplegia and epilepsy. The multivariate analysis revealed that the Apgar score at 1 minute, peak plasma ammonia concentration, birth weight and sex were significant factors affecting the prognosis of life.  相似文献   
3.
4.
In recent years, dramatic advances in the applications of molecular genetic techniques have made it possible to identify molecular defects in man that account for inherited metabolic diseases. Thus molecular genetic techniques has rapidly expanded our ability to diagnose disease. DNA diagnosis includes prenatal and presymptomatic diagnosis as well as identification of carriers of many inherited metabolic disorders. Disorders that are always caused by a specific mutation can be diagnosed by direct detection of the mutation, while diagnosis of disorders with genetic heterogeneity or unknown genetic defect can be based on polymorphism in linkage analysis. DNA amplification by the PCR has made possible the rapid identification of DNA sequences variations. After PCR, mutations can be detected by various methods such as restriction enzyme analysis, amplification refractory mutation system, dot blot hybridization, chemical cleavage, or single strand conformational polymorphism. In addition, the PCR technique can be applied to polymorphism analysis. These methods have made DNA diagnosis quicker, easier, and cheaper.  相似文献   
5.
The antitumorigenic effect of cryptoporic acid E (CPA-E), a dimeric drimane sesquiterpenoid isolated from the fungus Cryptoporus volvatus , on colon carcinogenesis was investigated. Female F344 rats given an intrarectal instillation of 2 mg of N-methyl-N-nitrosourea 3 times weekly in weeks 1 and 2 were fed diet containing 0.2% CPA-E from week 3. Femal ICR mice given 15 weekly intraperitoneal injections of 10 mg of 1,2-dimethylhydrazine/kg body weight during weeks 1 to 15 were fed diet containing 0.06% CPA-E from week 1. The experiment was terminated at week 35 for rats and at week 25 for mice. The incidence and the number of tumors per animal were reduced in CPA-E-fed animals compared to the controls: 31% vs. 75% (P<0.05) and 0.4±0.2 (SEM) vs. 0.9 ± 0.2 (0.1> P >0.05) in rats, and 31% vs. 63% (0.1>P>0.05) and 0.4±0.2 vs. 2.4 ± 0.8 (P<0.05) in mice (16 animals in each group). Intrarectal deoxycholic acid-induced colonic mucosal ornithine decarboxylase activity was significantly lowered in CPA-E-fed animals compared to controls. This shows an antipromoting activity of CPA-E against colon carcinogenesis. Thus, it was concluded that CPA-E inhibits colon cancer development in both rats and mice treated with 2 different colon carcinogens.  相似文献   
6.
A peculiar case of “nevus on nevus” was reported. A 67-year-old man had had a pigmented lesion in the left hypochondrial area since birth. The clinicopathologic findings of the pigmented lesion revealed a combination of speckled lentiginous nevus and patch-type blue nevus. This case of “nevus on nevus” is not described under the term of combined nevus as is current in the literature; it was considered to be a subtype of the type II atypical blue nevus described by Kawamura.  相似文献   
7.
Notch receptors and their ligands contribute to many developmental systems, but it is not apparent how they function after birth, as their null mutants develop severe defects during embryogenesis. Here we used the Cre-loxP system to delete the Delta-like 1 gene (Dll1) after birth and demonstrated the complete disappearance of splenic marginal zone B cells in Dll1-null mice. In contrast, T cell development was unaffected. These results demonstrated that Dll1 was dispensable as a ligand for Notch1 at the branch point of T cell-B cell development but was essential for the generation of marginal zone B cells. Thus, Notch signaling is essential for lymphocyte development in vivo, but there is a redundancy of Notch-Notch ligand signaling that can drive T cell development within the thymus.  相似文献   
8.
In the present study, we evaluated the potential of bradykinin (BK) to induce the release of neutrophil and monocyte chemotactic activity (NCA and MCA) and cytokines from an alveolar type II epithelial cell line, A549 cells. BK stimulated A549 cells to release NCA and MCA in a dose- and time-dependent manner (P < 0.001). Checkerboard analysis revealed that both NCA and MCA involved chemotactic and chemokinetic activity. Molecular sieve column chromatography showed three molecular weight masses (near 19 kd, 8 kd, and 400 d) for NCA and several molecular weight peaks (near 66 kd, 25 kd, 19 kd, 16 kd, and 400 d) for MCA. The release of NCA and MCA was inhibited by cycloheximide and lipoxygenase inhibitors (P < 0.01). The NCA and MCA were inhibited by leukotriene B4 (LTB4) receptor antagonist (P < 0.01), and the concentration of LTB4 was high enough for NCA and MCA. Antibodies to interleukin (IL)-8 and granulocyte colony-stimulating factor (G-CSF) attenuated NCA (P < 0.01), and antibodies to monocyte chemotactic protein-1 (MCP-1), G-CSF, and transforming growth factor (TGF)-β attenuated MCA (P < 0.01). The levels of IL-8, G-CSF, MCP-1, and TGF-β increased time dependently (P < 0.01). BK also stimulated the release of ILeukin-6 from A549 cells (P < 0.001). The receptors responsible for the release of NCA, MCA, and individual chemokines involved both BKB1 and BKB2 receptors. These data suggest that BK may stimulate alveolar type II pneumocytes to release inflammatory cytokines, which then may modulate the lung inflammation.  相似文献   
9.
A 43-year-old woman was diagnosed as having stage IV follicular lymphoma. Phenotypically, the lymphoma cells were CD5(-), CD10(+), CD19(+), CD20(+), CD23(-), HLA-DR(+), and IgM-lambda(+). Conventional chromosomal analysis showed a three-way t(3;14;18)(q27;q32;q21) in the lymphoma cells, which was confirmed by spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH). Immunohistochemistry revealed that both BCL2 and BCL6 proteins were expressed in the lymphoma cells, whereas only the BCL6 gene, and not the BCL2 gene, was rearranged by Southern blotting. The patient received combination chemotherapy and has been well for 3 years. This is the first reported case showing a three-way translocation involving 2 major lymphoma-specific abnormalities, 3q27 and t(14;18)(q32;q21).  相似文献   
10.
The effects of IL-7 on the growth and differentiation of thymocyteswere analyzed using murine fetal thymua organ cultures (FTOC)in the presence of mAbs specific for the conventional IL-7 receptor(1L-7R) and for the common (c) chain. In FTOC, the developmentof CD4CD8 double-negative thymocytes to CD4+CD8+double-positive (DP) and CD4+ or CD8+ single-positive (SP) cellswas not completely blocked by adding these mAbs, although cellgrowth was reduced by the treatment. To define a developingstage sensitive to the mAbs, most immature thymocytes, Pgp-1+c-kit cells, were cultured in the 2-deoxyguartosine treatedfetal thymus. In the presence of both mAbs in the culture, neitherDP nor SP thymocytes developed whereas either of the mAbs partiallyblocked their development. These results indicate that the Cchain is involved in early T cell development as an indispensablesubunlt of the functional IL-7 receptor complex.  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