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   530篇
  免费   15篇
  国内免费   7篇
耳鼻咽喉   4篇
儿科学   13篇
妇产科学   48篇
基础医学   44篇
口腔科学   5篇
临床医学   43篇
内科学   73篇
皮肤病学   3篇
神经病学   14篇
特种医学   20篇
外科学   116篇
综合类   14篇
预防医学   44篇
眼科学   6篇
药学   43篇
中国医学   7篇
肿瘤学   55篇
  2023年   8篇
  2022年   14篇
  2021年   17篇
  2020年   10篇
  2019年   10篇
  2018年   24篇
  2017年   11篇
  2016年   6篇
  2015年   12篇
  2014年   26篇
  2013年   33篇
  2012年   33篇
  2011年   35篇
  2010年   27篇
  2009年   17篇
  2008年   30篇
  2007年   30篇
  2006年   17篇
  2005年   20篇
  2004年   19篇
  2003年   21篇
  2002年   19篇
  2001年   9篇
  2000年   7篇
  1999年   4篇
  1995年   3篇
  1994年   6篇
  1992年   8篇
  1991年   7篇
  1990年   9篇
  1989年   4篇
  1988年   4篇
  1987年   2篇
  1986年   1篇
  1985年   3篇
  1984年   8篇
  1983年   4篇
  1982年   3篇
  1981年   1篇
  1980年   3篇
  1979年   3篇
  1978年   1篇
  1976年   1篇
  1975年   1篇
  1974年   5篇
  1973年   4篇
  1972年   2篇
  1971年   4篇
  1970年   3篇
  1960年   1篇
排序方式: 共有552条查询结果,搜索用时 218 毫秒
51.
52.
Eighteen women with hepatic cirrhosis were examined for plasma levels of testosterone, estrone, estradiol, progesterone and sex hormone binding globulin. For eight who were amenorrheic, with advanced liver cirrhosis and ascites, the reduction of testosterone and rise in estrone and sex hormone binding globulin concentrations were significant. Plasma extradiol and progesterone were lower than normal levels, but the differences were not statistically significant. The other ten patients were menstruating (mostly irregularly), and their hormonal levels were assessed in different states of their cycles. All of them did not ovulate, had low levels of plasma progesterone and also showed consistent estrone concentration excess relative to estradiol and significant lowering of testosterone and elevation of sex hormone binding globulin. These findings are compared with previous reports on males with liver cirrhosis.  相似文献   
53.
Two comparable groups of kidney transplant recipients were identified according to the age of their kidney donors. The first group (A) comprised 42 recipients of donors aged < 40 years, and the second group (B) comprised 48 recipients of donors aged > 50 years. The patients were followed for a mean period of 26 months (range 13–50 months). Post-transplant renal function and graft survival were assessed together with the frequency of post-transplant proteinuria and hypertension. More-over, the functional reserve of the grafts was determined by comparing the clearance values, obtained by both isotope and chemical means, before and after a combined infusion of dopamine and an amino acids preparation. The graft function was significantly better in group A according to the serum creatinine levels (µmol/l) at 1 month (107 ± 4.5 vs. 134 ± 10.7, P < 0.01), 12 months (119 ± 5.3 vs. 181 ± 88, P < 0.05) and at last follow-up visit (118 ± 6.2 vs. 223 ± 63, P < 0.03) for groups A and B, respectively. The graft survival in group A was significantly higher than that in group B (100 % vs. 87 % at 1 year, P < 0.05). The graft functional reserve was significantly better in group A than in group B. Post-transplant proteinuria was significantly more frequent in group B recipients (70 % vs. 40 %, P < 0.03). The age of the donors had no impact on the incidence of post-transplant hypertension. These observations suggest that the transplantation of a kidney from an older live kidney donor is associated with an inferior post-transplant outcome.  相似文献   
54.
55.
Flow cytometric DNA analysis and ABO(H) cell surface antigen expression were studied in 46 patients with cystectomies for carcinoma of bilharzial bladder. The most significant prognostic indicators were the DNA index and the status of the pelvic lymph nodes at operation. Diploid tumors were associated with a low metastatic potential (7.7%) and a better five-year survival (54%) in contrast to aneuploid cases that had a higher metastatic potential (45.5%) and a low five-year survival (21%). The ABO(H) isoantigen status did not correlate with pathologic parameters or the clinical course of these invasive bilharzial bladder tumors as was previously reported.  相似文献   
56.
A general survey was made on the zoosaprophagous insects and their associates in a natural ecosystem in the Egyptian western desert (80 km west of Alexandria, 12 km from the Mediterranean Sea shore). Two types of traps were used, one for flying insects and the other for soil-burrowing insects. Two types of decaying media were used as baits: the common freshwater fish (Tilapia zilii Gerv.) and the desert snail (Eremina desertorum). More than 30 insect species were trapped. The following orders and families were represented: Diptera (Calliphoridae, Sarcophagidae, Muscidae); Coleoptera (Histeridae, Scarabaeidae, Dermestidae, Tenebrionidae); Hymenoptera (Chalcididae, Pteromalidae, Eulophidae, Formicidae). Monthly totals of numbers trapped in each of these groups are presented.  相似文献   
57.
Progress toward clinical application of ESC-derived hematopoietic cellular transplantation will require rigorous evaluation in a large animal allogeneic model. However, in contrast to human ESCs (hESCs), efforts to induce conclusive hematopoietic differentiation from rhesus macaque ESCs (rESCs) have been unsuccessful. Characterizing these poorly understood functional differences will facilitate progress in this area and likely clarify the critical steps involved in the hematopoietic differentiation of ESCs. To accomplish this goal, we compared the hematopoietic differentiation of hESCs with that of rESCs in both EB culture and stroma coculture. Initially, undifferentiated rESCs and hESCs were adapted to growth on Matrigel without a change in their phenotype or karyotype. Subsequent differentiation of rESCs in OP9 stroma led to the development of CD34(+)CD45(-) cells that gave rise to endothelial cell networks in methylcellulose culture. In the same conditions, hESCs exhibited convincing hematopoietic differentiation. In cytokine-supplemented EB culture, rESCs demonstrated improved hematopoietic differentiation with higher levels of CD34(+) and detectable levels of CD45(+) cells. However, these levels remained dramatically lower than those for hESCs in identical culture conditions. Subsequent plating of cytokine-supplemented rhesus EBs in methylcellulose culture led to the formation of mixed colonies of erythroid, myeloid, and endothelial cells, confirming the existence of bipotential hematoendothelial progenitors in the cytokine-supplemented EB cultures. Evaluation of four different rESC lines confirmed the validity of these disparities. Although rESCs have the potential for hematopoietic differentiation, they exhibit a pause at the hemangioblast stage of hematopoietic development in culture conditions developed for hESCs.  相似文献   
58.
Regulatory T cells (Treg) has been documented to be protective against myocardial ischemia–reperfusion injury (MIRI). The administration of drugs which recruit Treg cells may participate in the cardioprotection of MIRI. The purpose of the present study was to investigate whether the add-on vildagliptin (vild) to standard treatment of MIRI prior to reperfusion could increase Treg recruitment, anti-inflammatory, and antioxidant effects of the standard treatment or not. Sixty diabetic patients with ST-segment elevation myocardial infarction were randomly divided into two equal groups: control group was given the standard medical treatment and vild group was given the standard medical treatment plus vild. There were no statistical differences between the mean of percentage of changes in nitric oxide, ischemia modified albumin, highly sensitive C reactive protein, and interferon-gamma levels in the studied groups. While, the percentages of changes of myeloperoxidase level, CD4+CD25+ Treg cells count, and transforming growth factor-beta1 level were significantly higher in vild group compared with control group. We concluded that addition of vild to standard medical treatment of MIRI could increase its effectiveness through recruitment of CD4+CD25+ Treg cells.  相似文献   
59.
OBJECTIVE: Polymorphonuclear cell functions frequently are impaired in critically ill patients, and restoration of normal functions could help to prevent nosocomial infections. The aim of this study was to evaluate the effects of pretreatment with granulocyte colony-stimulating factor (G-CSF) on bacterial pneumonia induced 48 hrs after peritonitis (cecal ligation and puncture [CLP]) in rats. DESIGN: Controlled animal study. SETTING: Research laboratory of an academic institution. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: First, the CLP model was characterized. Second, alveolar endotoxin instillation allowed us to evaluate the ability of neutrophils to migrate to airspaces after CLP was assessed. In the last set of experiments, CLP was followed by G-CSF treatment as a preventive therapy for subsequent bacterial superinfection induced by alveolar instillation. MEASUREMENTS AND MAIN RESULTS: CLP induced a brief increase in proinflammatory cytokines (tumor necrosis factor-alpha, interleukin-1beta) at the 6th hr followed by a longer-lived anti-inflammatory response (interleukin-10 increase from days 1 to 3) in plasma, compared with healthy rats. Impaired neutrophil migration to alveolar spaces denoting immunoparalysis was evidenced after endotracheal endotoxin instillation following CLP, compared with non-CLP rats challenged with endotoxin. No such impairment was found when G-CSF (100 microg/kg: glycosylated recombinant human G-CSF, Lenograstim) was given before endotoxin. G-CSF (100 microg/kg 24 and 48 hrs after CLP) given before endotracheal instillation increased bacterial clearance, as shown by counts in both bronchoalveolar lavage (8.9 x 10 +/- 2.8 x 10 colony-forming units/mL vs. 3.3 x 10 +/- 1.5 x 10 colony-forming units/mL with saline) and lung tissue (4.2 x 10 +/- 1.0 x 10 colony-forming units/g vs. 1.5 x 10 +/- 0.6 x 10 colony-forming units/g with saline). Furthermore, G-CSF pretreatment kept clearance in CLP rats similar to that in non-CLP rats challenged with. CONCLUSION: These results suggest that G-CSF (Lenograstim) may enhance host defenses in rats with peritonitis and immunoparalysis.  相似文献   
60.
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