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   10850篇
  免费   697篇
  国内免费   79篇
耳鼻咽喉   69篇
儿科学   214篇
妇产科学   90篇
基础医学   1459篇
口腔科学   206篇
临床医学   815篇
内科学   2865篇
皮肤病学   155篇
神经病学   781篇
特种医学   449篇
外科学   1707篇
综合类   44篇
一般理论   2篇
预防医学   250篇
眼科学   131篇
药学   1031篇
中国医学   24篇
肿瘤学   1334篇
  2023年   165篇
  2022年   304篇
  2021年   532篇
  2020年   287篇
  2019年   361篇
  2018年   412篇
  2017年   333篇
  2016年   339篇
  2015年   351篇
  2014年   374篇
  2013年   434篇
  2012年   655篇
  2011年   733篇
  2010年   381篇
  2009年   308篇
  2008年   582篇
  2007年   554篇
  2006年   487篇
  2005年   441篇
  2004年   431篇
  2003年   439篇
  2002年   408篇
  2001年   204篇
  2000年   228篇
  1999年   193篇
  1998年   115篇
  1997年   105篇
  1996年   78篇
  1995年   64篇
  1994年   49篇
  1993年   51篇
  1992年   112篇
  1991年   102篇
  1990年   73篇
  1989年   91篇
  1988年   71篇
  1987年   73篇
  1986年   71篇
  1985年   92篇
  1984年   60篇
  1983年   45篇
  1982年   25篇
  1979年   42篇
  1977年   26篇
  1976年   24篇
  1975年   25篇
  1974年   25篇
  1972年   33篇
  1970年   32篇
  1969年   32篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
We describe a patient with acute lymphoblastic leukemia (ALL) in whom hemopoiesis recovered after an autologous marrow graft purged by in vitro hyperthermia. A 17-year-old woman was diagnosed as having ALL in April 1985. After clinical remission was induced, marrow cells were harvested. The marrow cells were treated with hyperthermia at 42.0 degrees C for 1 h in the presence of alpha-interferon to eliminate residual leukemic cells, and then cryopreserved. In January 1990, during her fourth remission she was treated with busulfan and cyclophosphamide, and then received the thawed autologous marrow. Her hematopoietic recovery was prompt with normal trilineage regeneration without any life-threatening complications. She is in good health without evidence of a leukemic relapse at 6 months after autologous bone marrow transplantation. This case suggests that human multilineage progenitor cells retain self-renewal capacity in vivo even after treatment with heat and alpha-interferon in vitro followed by the freezing and thawing procedures.  相似文献   
12.
13.
We investigated the pathological and biochemical changes of skeletal muscle in rats with lysosomal acid lipase deficiency, which is an animal counterpart of human Wolman's disease. In the affected rats, the acid lipase activity for three different substrates, 4-methylumbelliferyl-oleate (18.9% of the normal control level), [14C]cholesteryl oleate (23.5%), and [14C]triolein (26.9%), was similarly decreased in the lysosomal fraction of skeletal muscle which was obtained by differential centrifugation. Histochemical studies showed that acid phosphatase activity was high in the endomysium and perimysium and in some muscle fibers. Some fibers showed vacuolar degeneration resembling "rimmed vacuoles". Ultrastructural studies demonstrated many membrane-bound lipid droplets in the muscle fibers, especially in the subsarcolemmal space, indicating that a low density lipoprotein (LDL) uptake pathway apparently existed in the muscle cells. However, such lipid accumulation was much greater in the interstitial cells and the endothelial cells. This distribution also suggests that LDL/cholesterol is supplied to muscle cells predominantly through endothelial cells.  相似文献   
14.
15.
Elective cesarean as a risk factor for transfusion after delivery of twins   总被引:1,自引:0,他引:1  
We examined deliveries of twins to identify factors most strongly associated with an increased risk of transfusion. We reviewed the obstetric records of 511 twin deliveries at the Japanese Red Cross Katsushika Maternity Hospital from 2003 through 2007. After 18 (3.5%) of these deliveries, transfusions were required. Transfusion was significantly more likely after elective cesarean delivery at a gestational aged of 37 weeks or more (odds ratio, 4.85; 95% confidence interval, 1.87-12.61). Emergency cesarean delivery (at > or =37 weeks' gestation) was not associated with an increased risk of transfusion. The delivery mode of twins should be carefully considered because of the increased risk of transfusion after elective cesarean delivery at a gestational age of 37 weeks or more.  相似文献   
16.
17.
We found a glutamine/arginine polymorphism at codon 349 of the hBUBR1 gene, encoding a protein kinase required for spindle assembly checkpoint function. The observed heterozygosity was estimated to be 45% in the Japanese population. This polymorphism may be helpful for genetic studies of many cancer types in which chromosomal instability is observed. Received: October 19, 1998 / Accepted: October 24, 1998  相似文献   
18.
We report three possibly disease-causing point mutations in one of the inner-ear-specific genes, KIAA1199. We identified an R187C mutation in one family, an R187H mutation in two unrelated families, and an H783Y mutation in one sporadic case of nonsyndromic hearing loss. In situ hybridization indicated that the murine homolog of KIAA1199 mRNA is expressed specifically in Deiters cells in the organ of Corti at postnatal day zero (Pn) P0 before the onset of hearing, but expression in those cells disappears by day P7. The signal of KIAA1199 was also observed in fibrocytes of the spiral ligament and the spiral limbus through to P21, when the murine cochlea matures. Thus, the gene product may be involved in uptake of potassium ions or trophic factors with a particular role in auditory development. Although the R187C and R187H mutations did not appear to affect subcellular localization of the gene product in vitro, the H783Y mutation did present an unusual cytoplasmic distribution pattern that could underlie the molecular mechanism of hearing impairment. Our data bring attention to a novel candidate for hearing loss and indicate that screening of mutations in inner-ear-specific genes is likely to be an efficient approach to finding genetic elements responsible for deafness.Nucleotide sequence data reported herein are available in the DDBJ/EMBL/GenBank databases; for details, see the electronic eatabase section of this article.  相似文献   
19.
20.
Chondroitin sulfate dipalmitoylphosphatidylethanolamine (CS-PE), when immobilized onto substratum, inhibited the adhesion of B16F10 mouse melanoma cells to fibronectin-coated dishes (anti-adhesion activity). CS-PE showed the most potent anti-adhesion activity for the melanoma cells among various GAG-PEs. CS-PE also inhibited the adhesion of B16F10 cells to Matrigel and the invasion of the cells into Matrigel. In the in vivo system of experimental metastasis, administration of B16F10 cells with CS-PE into C57BL/6 mice significantly inhibited lung metastasis. The inhibition degree of CS or hyaluronic acid-PE was lower than CS-PE. CS-PE administered intravenously into mice before the injection of B16F10 cells also inhibited metastasis. Pretreatment of B16F10 cells with CS-PE caused some but a lower degree of inhibition. When CS-PE was injected intravenously into mice, more binding in the lung was found than when CS was injected. CS-PE but not CS inhibited the retention in the lung of fluorochrome-labeled B16F10 cells when injected intravenously into mice. Since there was no significant effect of CS-PE on the viability and growth of B16F10 cells, the results suggest that CS-PE immobilized onto the subendothelial matrix may prevent melanoma cells from adhering to the subendothelial substrata of lung capillaries and inhibit subsequent invasion processes of metastasis.  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