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   2905篇
  免费   102篇
  国内免费   179篇
耳鼻咽喉   22篇
儿科学   53篇
妇产科学   24篇
基础医学   576篇
口腔科学   14篇
临床医学   166篇
内科学   842篇
皮肤病学   96篇
神经病学   133篇
特种医学   13篇
外科学   151篇
综合类   366篇
预防医学   163篇
眼科学   33篇
药学   320篇
  2篇
中国医学   48篇
肿瘤学   164篇
  2024年   3篇
  2023年   19篇
  2022年   43篇
  2021年   66篇
  2020年   42篇
  2019年   54篇
  2018年   55篇
  2017年   54篇
  2016年   78篇
  2015年   119篇
  2014年   189篇
  2013年   217篇
  2012年   178篇
  2011年   223篇
  2010年   169篇
  2009年   164篇
  2008年   159篇
  2007年   183篇
  2006年   174篇
  2005年   154篇
  2004年   92篇
  2003年   102篇
  2002年   71篇
  2001年   69篇
  2000年   60篇
  1999年   71篇
  1998年   41篇
  1997年   45篇
  1996年   38篇
  1995年   39篇
  1994年   36篇
  1993年   27篇
  1992年   17篇
  1991年   18篇
  1990年   14篇
  1989年   13篇
  1988年   21篇
  1987年   13篇
  1986年   13篇
  1985年   10篇
  1984年   7篇
  1983年   5篇
  1982年   10篇
  1981年   5篇
  1980年   3篇
  1979年   1篇
  1978年   2篇
排序方式: 共有3186条查询结果,搜索用时 31 毫秒
21.
To investigate immune effects of interferon (IFN) therapy in hepatitis B e antigen (HBeAg)-positive chronic hepatitis B, serum immunoglobulin concentrations and peripheral lymphocyte subpopulations were sequentially studied before, during, and after therapy in nine patients who were treated with recombinant human -IFN in doses ranging from 3 to 10 million units per day for 28 days. Serum immunoglobulin A levels decreased significantly, from 414±23 mg/dl (mean ± SE) to 379±28 mg/dl (P<0.05), after the first week of therapy and to a bottom value of 323±20 mg/dl (P<0.001) at the fourth week. Immunoglobulin G levels decreased significantly, from 2603±175 to 2328±169 mg/dl (P<0.005), after the first week of therapy and to a bottom value of 2005±199 mg/dl (P<0.001) at the fourth week. Immunoglobulin M levels were also reduced significantly after 3 weeks of therapy (from 229±23 to 188±15 mg/dl;P<0.01). These reductions in immunoglobulins A, G, and M returned to pretreatment levels by 4 months after the end of the therapy. In lymphocyte subpopulations, significant depressions were found in CD3-, CD4-, CD8-, and B1-positive cells in peripheral blood after the first week of therapy (CD3, from 1700±114 to 1234±114/mm3,P<0.005; CD4, from 1036±88 to 780±64/mm3,P<0.005; CD8, from 620±57 to 426±60/mm3,P<0.05; and B1, from 519±84 to 276±48/mm3,P<0.01) followed during therapy, while Leul la-positive cells did not change significantly. During the 6-month follow-up period, three patients had a sustained clinical remission in which HBeAg disappeared from serum. Disappearance of HBeAg was unassociated with initial levels or percentage changes of serum immunoglobulins and peripheral lymphocytes expressing each of the test markers in these patients. These findings suggest that immune effects of IFN therapy are independent from its antiviral effects.  相似文献   
22.
The changes in thermoregulatory effectors produced by an injection of polyriboinosinic acid: polyribocytidylic acid (Poly I:C) or interferon were assessed and compared in control rats, in rats with hypothalamic somatostatin (SS) receptor blockade and in rats with hypothalamic SS depletion. Intrahypothalamic (i.h., 0.05–0.50 μg) or intraperitoneal (i.p., 100–600 μg) administration of Poly I:C caused a dose-related rise in colon temperature in control rats at all ambient temperatures (Ta) studied. A Poly I:C-induced fever was produced by increased metabolism at a Ta of 8 °C, whereas at 30 °C, it was caused by cutaneous vasoconstriction. At a Ta of 22 °C, the fever was caused by increased metabolism and cutaneous vasoconstriction. On the other hand, i.h. administration of SS-14 antagonist (0.1–0.5 ng) caused a dose-related fall in colon temperature at Ta of 8 °C or 22 °C. At a Ta of 8 °C, the hypothermia was caused by decreased metabolism, whereas at 22 °C, it was caused by decreased metabolism and cutaneous vasodilation. At a Ta of 30 °C, the thermoregulatory effectors were not affected by SS-14 antagonist treatment. Furthermore, the fever induced by Poly I:C or interferon was significantly reduced by pretreatment of rats with an i.p. dose of cysteamine (30 mg. kg−1) or an i.h. dose of SS-14 antagonist (0.1 ng). The results indicate that a somatostatinergic pathway in rat hypothalamus may mediate the fever induced by interferon or its inducer Poly I:C.  相似文献   
23.
Komatsu T  Takeuchi K  Yokoo J  Gotoh B 《Virology》2004,325(1):137-148
We here report a molecular basis for downregulation of interferon (IFN)-beta production by V and C proteins of Sendai virus (SeV). The infection of HeLa cells with SeV poorly induced IFN-beta even if the expression of C/C' was disrupted. In contrast, when the expression of C/C'/Y1/Y2 or V/W was disrupted, SeV infection strongly induced IFN-beta production and significantly activated the interferon regulatory factor (IRF)-3 pathway. The independent expression of C or V inhibited the double-stranded (ds) RNA- or Newcastle disease virus (NDV)-induced activation of IRF-3 and NF-kappa B, as well as the IFN-beta promoter. This inhibitory effect was also observed when Y1, Y2, or a C-terminal half fragment (aa 85-204) of C was independently expressed. Phosphorylation and homodimer formation of IRF-3 were suppressed not only in cells infected with SeV capable of expressing both C/C'/Y1/Y2 (or Y1/Y2) and V/W, but also in HeLa cells constitutively expressing Y1. These results suggest that C, Y1, Y2, and V block signaling pathways leading to IRF-3 activation to downregulate IFN-beta production.  相似文献   
24.
Summary Even though the enhancement of the lyitc capacity and the kinetics of lysis of natural killer cells (NK) by interferon has been well documented, an increase of the target-effector cell binding percentage is still disputed. We, therefore, modified the Grimm-Bonavida single-cell assay so that 400 to 600 cells per individual determination could be reliably evaluated. Using this assay, which makes possible separate determination of effector-target cell binding and target lysis, we demonstrated that, in addition to lytic capacity, target-effector cell binding is also increased by preincubating NK with 100 to 1,000 IU interferon alpha 2 per 106 cells. Our data indicate that interferon alpha 2 induces pre-NK cells to bind target cells and that it activates these pre-NK cells to kill the targets.Abbreviations NK Natural killer cells - LCMV Lymphocytic choriomeningitis virus - IFN Interferon - FCS Fetal calf serum - RPMI 1640 Culture medium Dedicated to Prof. H.D. Waller on the occasion of his 60th birthday  相似文献   
25.
目的 探讨聚乙二醇α-2a干扰素(PEG INFα-2a)治疗HBeAg阳性慢性乙型肝炎的疗效和安全性。方法 按随机对照原则选择80例HBV DNA、HBeAg阳性的慢性乙型肝炎患者,按1:1随机分配进入PEG INFa-2a组和IFNα-2a组。结果 治疗6个月时,PEG INFα-2a组HBeAg血清转换率(45.7%)高于IFNα-2a组(35.1%),但P〉0.05。停药6个月后,持续的HBeAg血清转换率分别为48.6%和37.8%,P〉0.05。停药6个月后,持续的HBVDNA阴转率分别为62.9%和45.9%,P〉0.05。治疗后,两组的丙氨酸转氨酶(ALT)复常率差异无显著性,为62.9%和45.9%,停药后6个月,两组的联合应答率分别为57.1%和40.5%。PEG INFα-2a组有3例患者HBsAg阴转,而IFNα-2a组仅有1例患者HBsAg阴转。两组有相似的不良反应,不良反应间差异无统计学意义,两组治疗过程中均未发生重要的不良事件。结论PEG INFα-2a治疗HBeAg阳性的慢性乙型肝炎疗效优于普通干扰素IFN-2a,耐受性和安全性好。  相似文献   
26.
丙型肝炎病毒基因分型及其与干扰素治疗应答的关系   总被引:4,自引:0,他引:4  
目的为了解山西省丙型肝炎病毒的基因型和基因型对干扰素疗效的预示价值。方法用HCV5’NC区酶切分型方法对94例丙型肝炎病人进行基因分型,并观察其中45例患者对干扰素α1b治疗的应答。结果显示HCVⅠ组(Ⅰ、Ⅱ型)感染80例(851%),HCVⅡ组(Ⅲ、Ⅳ型)感染12例(128%),HCVⅠ/Ⅱ组混合感染2例(21%)。在接受干扰素治疗的病例中,HCVⅠ组感染(35例)的应答率为371%,持续应答率为171%,而Ⅱ组感染(10例)的应答率为80%,持续应答率为60%,两组相比,有显著性差异(P<005,P<0025)。结论表明山西省以HCVⅠ组感染为主,干扰素对HCVⅡ组感染的疗效优于HCVⅠ组感染,HCV基因型有预测干扰素疗效的意义。  相似文献   
27.
Cancer patients were given a recombinant mutant interferon by alternating IM and IV injections with weekly escalation of doses from 0.1 to 400 million U. Antibodies specific to the interferon of the IgG class were detected in 24 of 30 patients using an indirect enzyme-linked immunosorbent assay. Serum from only 1 of the 30 patients had detectable ability to neutralize interferon biological activity. Thein vivo interferon serum level, assayed as antiviral activity immediately after IV injection, was not lower than levels seen in the absence of antibodies. Antibodies did not alter the kinetics of clearance of interferon from the serum after IV administration. Antibody levels progressively decreased when interferon administration was discontinued. In most patients antibody levels decreased during a maintenance period when interferon was being administered only by the IV route. In a subsequent trial interferon was given IV, and antibody developed in only 2 of 36 patients. In contrast, in a trial in which interferon was given IM, 20 of 25 patients developed antibody. No antibody-related clinical sequelae could be detected in any of these patients.  相似文献   
28.
Ahmed M  Cramer SD  Lyles DS 《Virology》2004,330(1):34-49
Because of its potent ability to induce apoptosis, vesicular stomatitis virus (VSV) is an attractive candidate as an oncolytic virus for tumor therapy. Previous studies have suggested that VSV selectively infects tumor cells due to defects in their antiviral responses making them more susceptible to VSV infection than normal cells. We tested this hypothesis in the prostate tumor system by comparing LNCaP and PC-3 prostate tumor cells to benign human prostatic epithelial cells from patient prostatectomy specimens. We compared the cell killing ability of a recombinant virus containing a wild-type (wt) M protein (rwt) and an isogenic M protein mutant virus (rM51R-M) that induces interferon (IFN) in infected cells and should display a greater selectivity for tumor cells. Our results showed that in single-cycle infection experiments, LNCaP cells were sensitive to killing by both wt and mutant viruses, while PC-3 cells were highly resistant to VSV-induced cell killing. LNCaP and benign prostate cells were similarly susceptible to both viruses, indicating that normal prostate cells are not inherently resistant to killing by VSV. In each of the cell lines, the rM51R-M virus induced similar levels of apoptosis to rwt virus, showing that the M protein does not play a significant role in apoptosis induction by VSV in these cells. In multiple-cycle infection experiments, LNCaP cells were more sensitive than benign prostatic epithelial cells to virus-induced cell killing by rM51R-M virus, but not rwt virus. Both viruses were equally effective at reducing LNCaP tumor volume in vivo following intratumoral and intravenous inoculation in nude mice, while PC-3 tumors were resistant to VSV treatment. None of the mice treated with rM51R-M virus died as a result of virus infection, while 50-71% of mice treated with rwt virus succumbed to virus infection. Similarly, when inoculated by the more sensitive intranasal route, the rM51R-M virus was less pathogenic than the rwt virus from which it was derived. These results indicate that M protein mutant viruses are superior candidates as oncolytic viruses for therapies of prostate tumors, but future strategies for use of VSV will require testing individual tumors for their susceptibility to virus infection.  相似文献   
29.
目的:探究人乳头状瘤病毒(HPV)感染并阴道上皮内瘤变(VAIN)患者采用干扰素配合CO2激光治疗的应用效果。方法:选取常德市第一人民医院2017年7月至2019年7月收治的194例HPV感染并VAIN患者,依据随机数字表法分组为A组(64例,采用CO2激光治疗),B组(64例,采用CO2激光配合保妇康栓治疗),C组(66例,采用CO2激光配合干扰素治疗),比较各组患者的疗效。结果:治疗后C组患者的阴道出血量、阴道排液量低于A组、B组,且阴道出血时间、阴道排液时间少于A组、B组,差异具有统计学意义(P <0.05)。治疗后C组患者不同时间段的病变逆转率均高于A组、B组,差异具有统计学意义(P <0.05)。治疗后2年各组患者恶化率比较,差异无统计学意义(P> 0.05)。C组患者的不同时段病变复发率均低于A组、B组,且不同时段HPV转阴率均高于A组、B组,差异具有统计学意义(P <0.05)。结论:干扰素配合CO2激光治疗可显著减轻本研究患者术后阴道出血...  相似文献   
30.
目的观察重组人干扰素α2b雾化吸入联合远红外止咳贴治疗毛细支气管炎的效果。方法选取2018年3月至2020年3月玉林市妇幼保健院收治的80例毛细支气管炎患儿,采用随机数字表法分为观察组与对照组,每组各40例。对照组给予常规综合治疗,观察组在常规综合治疗的基础上给予氧气驱动雾化吸入α2b干扰素联合远红外止咳贴治疗。比较两组治疗后的临床疗效、临床症状消失时间、住院时间以及肺部功能。结果观察组临床总有效率高于对照组,差异有统计学意义(P<0.05);观察组喘憋消失时间、咳嗽消失时间、肺部啰音消失时间、体温恢复正常时间、住院时间均短于对照组,差异有统计学意义(P<0.05);观察组治疗后潮气量、达峰时间比、达峰容积比均高于对照组,差异有统计学意义(P<0.05)。结论雾化吸入干扰素α2b联合远红外止咳贴治疗毛细支气管炎对提高治疗有效率,缩短临床症状消失时间、住院时间,改善肺功能具有重要作用,值得临床推广使用。  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