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   1837篇
  免费   163篇
  国内免费   3篇
耳鼻咽喉   99篇
儿科学   71篇
妇产科学   33篇
基础医学   292篇
口腔科学   29篇
临床医学   185篇
内科学   425篇
皮肤病学   12篇
神经病学   135篇
特种医学   64篇
外科学   174篇
综合类   28篇
一般理论   2篇
预防医学   68篇
眼科学   78篇
药学   175篇
肿瘤学   133篇
  2021年   14篇
  2020年   17篇
  2019年   14篇
  2018年   17篇
  2017年   18篇
  2016年   16篇
  2015年   20篇
  2014年   23篇
  2013年   32篇
  2012年   64篇
  2011年   50篇
  2010年   39篇
  2009年   36篇
  2008年   64篇
  2007年   68篇
  2006年   61篇
  2005年   61篇
  2004年   63篇
  2003年   64篇
  2002年   59篇
  2001年   56篇
  2000年   75篇
  1999年   43篇
  1996年   20篇
  1995年   15篇
  1994年   19篇
  1993年   18篇
  1992年   55篇
  1991年   59篇
  1990年   53篇
  1989年   60篇
  1988年   53篇
  1987年   70篇
  1986年   57篇
  1985年   66篇
  1984年   43篇
  1983年   30篇
  1982年   29篇
  1981年   21篇
  1980年   15篇
  1979年   44篇
  1978年   25篇
  1977年   30篇
  1976年   34篇
  1975年   17篇
  1974年   18篇
  1973年   20篇
  1972年   18篇
  1970年   16篇
  1966年   15篇
排序方式: 共有2003条查询结果,搜索用时 15 毫秒
131.
The effect of indomethacin as an antagonist to prostaglandin was evaluated on a series of 16 women during spontaneous labour in the ninth month of pregnancy. The evaluation of the effect of indomethacin on the progression of labour was determined by the deviation from the normal curve of Friedman. In 8 cases there was complete cessation of labour from 3 to 192 hours and in 8 additional cases there was protraction of the active phase from 3 to 17 hours. In 2 cases there was no effect. Seven births terminated spontaneously and in 9 cases it was necessary to administer pitocin intravenously to strengthen or renew contractions in order to terminate the pregnancy. There is no correlation between the obstetric state (the degree of cervical dilation, or effacement or rupture of membranes) at the time of indomethacin administration and the uterine response, or the speed of return to the normal curve of Friedman. The effect of indomethacin, as an antagonist to prostaglandin, at the time of labour was studied.  相似文献   
132.
A case of ectodermal dysplasia and aplastic anemia is presented in which a cell-mediated immunodeficiency led to a fatal Pneumocystis carinii infection. Elevated levels of IgG, IgA and IgD were present with normal specific antibody titres. A deficient cell-mediated immunity was documented by low T cell numbers, poor in vitro mitogenic responses, negative skin tests and by the histologic finding at autopsy of thymic dysplasia.  相似文献   
133.
Maize co-contamination with aflatoxin B1 (AFB1) and fumonisin B1 (FB1) is frequently found in several countries. Although the alterations on nutritional and immunologic parameters induced by these mycotoxins, when administered individually, are partially characterised, little is known about the effects induced in animals by a subchronic administration of both toxins mixtures. We have studied the nutritional and immunological alterations induced in rats fed during 90 days with a diet without mycotoxins, containing 40 ppb AFB1, and with a diet containing a mixture of 40 ppb AFB1 and 100 ppm FB1. Animals fed with the mixture of toxins obtained lower body weight than the control ones. The mitogenic response of spleen mononuclear cells (SMC) in vivo was higher in animals fed with AFB1. In in vitro studies, lower proliferations of SMC pre-exposed to AFB1 and to the mixture of toxins were detected. The SMC of animals fed with AFB1 produced lower levels of IL-2, higher of IL-4 and equal levels of IL-10. The SMC of animals fed with both toxins produced higher levels of IL-4, lower of IL-10 and equal levels of IL-2. The SMC preincubated with an AFB1-FB1 mixture produced higher concentrations of IL-4, lower of IL-10 and equal levels of IL-2. The peritoneal macrophages of animals that consumed AFB1 released less H(2)O(2), while animals fed with the mixture of toxins produced higher levels. In in vitro studies, macrophages pre-exposed to the mixture of toxins released less H(2)O(2). These results show different immunobiological effects produced by a mixture of mycotoxins in comparison to the individual action of the same toxins.  相似文献   
134.
The past 100 years have witnessed dramatic shifts in the concept of ideal surgical goals and operative technique in tonsil surgery. Surgeons are reviving a technique of intracapsular tonsillectomy with increasing precision thanks to modern technology. With intracapsular tonsillectomy, pediatric patients recover faster, use less pain medication, and have a lower risk of dehydration and hemorrhage. Various considerations will dictate the adoption of this technology in the coming years. This current review explores concepts and controversies surrounding tonsillectomy with a focus on quality improvement.  相似文献   
135.
The in vitro effect of ciprofloxacin and pefloxacin on growth of normal hematopoietic progenitor cells and on leukemic cell lines was investigated. Ciprofloxacin and pefloxacin caused dose-dependent inhibition of colony formation both from normal bone marrow cells and from the leukemic line K-562 cells. This inhibition exerted by ciprofloxacin and pefloxacin was statistically significant at concentrations of 25 micrograms/ml and above. Ciprofloxacin appeared to be the most potent inhibitor of colony formation among the antimicrobial agents tested. Although the inhibitory effect of pefloxacin on normal hematopoietic stem cells was similar to that of cefazolin and chloramphenicol, the inhibitory effect of pefloxacin on leukemic cells was more prominent than that of cefazolin and chloramphenicol. In a proliferation assay in liquid culture of the cell line HL-60, ciprofloxacin and pefloxacin caused a dose-dependent inhibition of cell proliferation. Both drugs failed to induce cellular differentiation, as assessed by the nitrogen blue tetrazolium dye reduction assay. In therapeutic concentrations no cumulative toxic effect of the combination of ciprofloxacin with cytosine-arabinoside, vincristine, actinomycin D and doxorubicin on colony formation by HL-60 cells was observed. It is concluded that ciprofloxacin does not exert in vitro inhibitory effect on human leukemic cells when assayed at concentrations of less than or equal to 5 micrograms/ml. However, at concentrations of 25 and 50 micrograms/ml of ciprofloxacin alone and in combination with several antineoplastic agents exerts an inhibitory effect on colony formation.  相似文献   
136.
The mechanism of intestinal secretion of the difluorinated quinolone sparfloxacin was investigated with the epithelial cell line Caco-2 and was compared to that of the P-glycoprotein (P-gp) substrate vinblastine. The P-gp inhibitors verapamil and progesterone significantly increased the epithelial cell accumulation of both vinblastine and sparfloxacin. This increase is likely to result from an inhibition of drug secretion since both vinblastine uptake and sparfloxacin uptake are known to proceed through a passive transmembrane diffusion. The unidirectional fluxes across cell monlayers grown on permeable filters indicated that a net secretion of sparfloxacin and vinblastine occurred across Caco-2 cells. These secretions were significantly inhibited by the MDR-reversing agent verapamil. We conclude that the P-gp is likely to be involved in the intestinal elimination of the difluorinated quinolone sparfloxacin.  相似文献   
137.
Computed tomography (CT) after abdominoperineal (AP) resection for rectal carcinoma is a routine procedure for the detection of recurrent tumor and distal metastases. We reviewed sequential CT scans after AP resection in 52 patients in order to see whether the urinary tract as a neighboring organ is involved in recurrent malignancy. Bladder displacement in itself was not associated with hydronephrosis. Such hydronephrosis developed, however, in 14 patients--13 with a presacral mass, and one with retroperitoneal lymphadenopathy. In 23 of the 52 patients a presacral mass appeared, either fibrosis, infection, or recurrence. Severe hydronephrosis was found only with malignancy. We suggest that marked hydronephrosis associated with a presacral mass after AP resection is an indirect sign of malignancy.  相似文献   
138.
139.
140.
Summary Two patients with hyponatremia (130 mEq/l and 122 mEq/l, respectively), and rickettsial disease are described. The causes of hyponatremia were attributed to rickettsial vasculitis and increased capillary permeability in the first patient and to the syndrome of inappropriate anti-diuretic hormone (ADH) secretion in the second patient. The differentiation between the mechanisms was established by measurement of urinary sodium excretion which was low in the first patient (7 mEq/l) and high in the second patient (60 mEq/l), and levels of ADH that were inappropriately high in the second patient (7–9 pg/ml) in the presence of low plasma osmolality. The differentiation between these causes of hyponatremia has important therapeutic implications.
Hyponatriämie bei Rickettsiose
Zusammenfassung Es werden zwei Patienten beschrieben, die bei einer Rikkettsien-Infektion eine Hyponatriämie von 130 mÄq/l bzw. 122 mÄq/l entwickelten. Die Ursache für die Hyponatriämie wird beim ersten Patienten in einer Rikkettsien-Vaskulitis mit erhöhter Kapillarpermeabilität und beim zweiten in einer inadäquaten Sekretion von antidiuretischem Hormon (ADH) gesehen. Durch Messung der Natriumausscheidung im Urin war eine Differenzierung der beiden Pathomechanismen möglich: beim ersten Patienten war die Natriumausscheidung mit 7 mÄq/l niedrig und beim zweiten mit 60 mÄq/l hoch. Zudem waren die ADH-Spiegel beim zweiten Patienten mit 7–9 pg/ml bei geringer Plasmaosmolalität unangemessen hoch. Die Unterscheidung der Ursachen der Hyponatriämie hat wichtige therapeutische Konsequenzen.
  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