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   1732篇
  免费   96篇
  国内免费   42篇
耳鼻咽喉   2篇
儿科学   39篇
妇产科学   3篇
基础医学   228篇
口腔科学   7篇
临床医学   330篇
内科学   169篇
皮肤病学   13篇
神经病学   10篇
特种医学   45篇
外科学   101篇
综合类   228篇
预防医学   316篇
眼科学   7篇
药学   289篇
  1篇
中国医学   47篇
肿瘤学   35篇
  2023年   15篇
  2022年   34篇
  2021年   71篇
  2020年   42篇
  2019年   44篇
  2018年   44篇
  2017年   33篇
  2016年   42篇
  2015年   69篇
  2014年   100篇
  2013年   116篇
  2012年   103篇
  2011年   102篇
  2010年   73篇
  2009年   89篇
  2008年   94篇
  2007年   89篇
  2006年   76篇
  2005年   101篇
  2004年   70篇
  2003年   58篇
  2002年   74篇
  2001年   45篇
  2000年   40篇
  1999年   23篇
  1998年   24篇
  1997年   27篇
  1996年   27篇
  1995年   18篇
  1994年   22篇
  1993年   14篇
  1992年   11篇
  1991年   14篇
  1990年   10篇
  1989年   8篇
  1988年   11篇
  1987年   3篇
  1986年   4篇
  1985年   1篇
  1984年   2篇
  1983年   4篇
  1982年   6篇
  1981年   3篇
  1980年   4篇
  1979年   3篇
  1978年   1篇
  1977年   3篇
  1976年   2篇
  1974年   1篇
排序方式: 共有1870条查询结果,搜索用时 15 毫秒
81.
瞿理华 《齐鲁药事》2014,(3):182-183,186
目的观察卡介菌多糖核酸治疗白癜风的临床疗效。方法将68例白癜风患者随机分为两组,治疗组36例肌注卡介菌多糖核酸注射液联合外用30%补骨脂酊,对照组32例单纯外用30%补骨脂酊,给药3个月。分别用流式细胞术和ELISA方法检测卡介苗多糖核酸治疗白癜风前后患者外周血T细胞亚群、IL-10和IFN-γ的水平。结果治疗组总有效率为91.7%,对照组总有效率59.4%,治疗组显著优于对照组(P<0.01)。卡介菌多糖核酸治疗后,患者CD4+百分比及CD4+/CD8+比值较治疗前升高,CD8+百分比降低,IFN-γ水平升高(P<0.05),IL-10水平下降(P<0.05)。结论卡介菌多糖核酸可显著改善患者细胞免疫功能,能有效治疗白癜风。  相似文献   
82.

Background

Although maintenance bacillus Calmette-Guérin (BCG) is the recommended treatment in high-risk non–muscle-invasive bladder cancer (NMIBC), its efficacy in older patients is controversial.

Objective

To determine the effect of age on prognosis and treatment outcome in patients with stage Ta T1 NMIBC treated with maintenance BCG.

Design, setting, and participants

A total of 957 patients with intermediate- or high-risk Ta T1 (without carcinoma in situ) NMIBC were randomized in European Organization for Research and Treatment of Cancer (EORTC) trial 30911 comparing six weekly instillations of epirubicin, BCG, and BCG plus isoniazid followed by three weekly maintenance instillations over 3 yr.

Outcome measurements and statistical analysis

Cox multivariate proportional hazards regression models were used to assess the relative importance of age for recurrence, progression, overall survival, and NMIBC-specific survival with adjustment for EORTC risk scores.

Results and limitations

Overall, 822 eligible patients were included: 546 patients in the BCG with or without INH arms and 276 in the epirubicin arm. In patients treated with BCG with or without INH, 34.1% were >70 yr of age and 3.7% were >80 yr. With a median follow-up of 9.2 yr, patients >70 yr had a shorter time to progression (p = 0.028), overall survival (p < 0.001), and NMIBC-specific survival (p = 0.049) after adjustment for EORTC risk scores in the multivariate analysis. The time to recurrence was similar compared with the younger patients. BCG was more effective than epirubicin for all four end points considered, and there was no evidence that BCG was any less effective compared with epirubicin in patients >70 yr.

Conclusions

In intermediate- and high-risk Ta T1 urothelial bladder cancer patients treated with BCG, patients >70 yr of age have a worse long-term prognosis; however, BCG is more effective than epirubicin independent of patient age.

Patient summary

Intravesical bacillus Calmette-Guérin for non–muscle-invasive bladder cancer is less effective in patients >70 yr of age, but it is still more effective than epirubicin.

Trial registration

This study was registered with the US National Cancer Institute clinical trials database (protocol ID: EORTC 30911; http://www.cancer.gov/clinicaltrials/search/view?cdrid=77075&version=HealthProfessional&protocolsearchid=12442243#StudyIdInfo_CDR0000077075).  相似文献   
83.
Bacillus thuringiensis (Bt) is the best known and most widely used of all pesticidal microbes. The aim of this study was to assess the toxicity of a new formulation of Bacillus thuringiensis var israelensis SH-14 in rats through acute dermal toxicity, dermal and eye irritation experiments. The acute dermal toxicity and dermal and eye irritation studies were performed using rabbits according to the United States Environmental Protection Agency guidelines 885.3100, 870.2500 and 870.2500, respectively. The skin sensitization study was carried out in accordance to the EPA OPPTS 870.2600 using guinea pigs. There was no mortality and no evidence of treatment-related toxicity in acute dermal toxicity test. No dermal responses, including erythema/eschar or edema, were found in rabbits treated with the new formulation of Bti SH-14. Minimum response was observed after eye application of test substance. No skin sensitization reactions were observed after the challenge with the new formulation of Bti SH-14 in the Bti SH-14-treated guinea pigs. In summary, the present study demonstrated that the new formulation of Bti SH-14 is not acutely toxic via dermal route, has low eye irritation and would not cause dermal irritation or hypersensitivity to tested animals.  相似文献   
84.
目的 对海洋芽孢杆菌B-9987中macrolactin生物合成基因簇及其关键基因进行分析、鉴定及功能研究。方法 通过生物信息学手段对基因簇的基因组成和功能结构域进行了分析;构建了用于酰基转移酶基因高表达的大肠杆菌—芽孢杆菌穿梭载体,采用电击转化方法导入B-9987之中进行高表达。 结果 macrolactins是由位于同一个操纵子的8个基因bmmA-I所编码的反式酰基转移酶聚酮合酶体系组装而成,反式酰基转移酶(trans-acyltransferase,trans-AT)BmmA的高表达使macrolactin A的产量提高了约0.6倍。结论 macrolactin生物合成基因簇在具有生物防治活性的芽孢杆菌中普遍存在,且高度保守;反式酰基转移酶的高表达能够增加macrolactin A的产量。  相似文献   
85.
目的:探讨双歧杆菌四联活菌片治疗小儿非感染性腹泻的临床效果及对血清IL-6、IL-17表达的影响。方法选取2013年2月~2014年6月本院收治的120例非感染性腹泻小儿,将其随机分为观察组和对照组,各60例,对照组采用常规方法治疗,观察组在对照组基础上采用双歧杆菌四联活菌片治疗,比较两组的总有效率、腹泻停止时间、住院时间和IL-6、IL-17水平。结果观察组总有效率为96.67%,高于对照组的85.00%,差异有统计学意义(P<0.05);观察组腹泻停止时间和住院时间均短于对照组,差异有统计学意义(P<0.05);治疗72 h后,观察组IL-6、IL-17水平显著低于对照组(P<0.05)。结论双歧杆菌四联活菌片治疗小儿非感染性腹泻可缩短患儿腹泻停止时间及住院时间,降低IL-6、IL-17水平,具有显著的临床疗效,值得推广应用。  相似文献   
86.
Yingying Wang  Zhaonong Hu  Wenjun Wu 《Toxins》2015,7(12):5448-5458
Bacillus thuringiensis (Bt) Cry toxins from the Cry1A family demonstrate significantly different toxicities against members of the family Noctuidae for unknown reasons. In this study, membrane potential was measured and analyzed in freshly isolated midgut samples from Mythimna separata and Agrotis ipsilon larvae under oral administration and in vitro incubation with Bt toxin Cry1Ab to elucidate the mechanism of action for further control of these pests. Bioassay results showed that the larvae of M. separata achieved a LD50 of 258.84 ng/larva at 24 h after ingestion; M. separata larvae were at least eightfold more sensitive than A. ipsilon larvae to Cry1Ab. Force-feeding showed that the observed midgut apical-membrane potential (Vam) of M. separata larvae was significantly depolarized from −82.9 ± 6.6 mV to −19.9 ± 7.2 mV at 8 h after ingestion of 1 μg activated Cry1Ab, whereas no obvious changes were detected in A. ipsilon larvae with dosage of 5 μg Cry1Ab. The activated Cry1Ab caused a distinct concentration-dependent depolarization of the apical membrane; Vam was reduced by 50% after 14.7 ± 0.2, 9.8 ± 0.4, and 7.6 ± 0.6 min of treatment with 1, 5, and 10 μg/mL Cry1Ab, respectively. Cry1Ab showed a minimal effect on A. ipsilon larvae even at 20 μg/mL, and Vam decreased by 26.3% ± 2.3% after 15 min. The concentrations of Cry1Ab displayed no significant effect on the basolateral side of the epithelium. The Vam of A. ipsilon (−33.19 ± 6.29 mV, n = 51) was only half that of M. separata (−80.94 ± 6.95 mV, n = 75). The different degrees of sensitivity to Cry1Ab were speculatively associated with various habits, as well as the diverse physiological or biochemical characteristics of the midgut cell membranes.  相似文献   
87.
BackgroundDiagnosis of genital tuberculosis (TB) as a cause of infertility still remains a diagnostic dilemma for clinicians, as no standard guidelines exist. The recently proposed best practices for genital TB diagnosis have not been evaluated yet in India.ObjectivesTo implement best practices to diagnose and treat likely genital TB as a cause of infertility.MethodsBetween April 2016 and June 2018, consenting women seen at a tertiary hospital infertility clinic were assessed by thorough TB related clinical history, ultrasonography, tuberculin skin test (TST), and ESR. Those with suspected genital TB underwent laparohysteroscopy. Clinical and laboratory characteristics were compared between likely (microbiologically confirmed or probable TB) and unlikely (possible and no genital TB) genital TB. Fertility outcome was assessed among women initiated on anti-TB treatment (ATT).ResultsOf 185 women seeking infertility care, likely genital TB was identified among 29 (15.7%) women, with 6 (21%) confirmed and 23 (79%) probable genital TB. Compared to unlikely genital TB cases, the likely genital TB group were found to have past history of TB (p < 0.001); positive TST (p = 0.002) and elevated ESR (p = 0.001). Among the likely genital TB group, all 6 confirmed genital TB were started on ATT and 2 (33.3%) conceived. Of 5 probable genital TB started on ATT, 3 (60%) conceived.ConclusionApproximately 1/6th of women seeking infertility care met the criteria for likely genital TB. Conception among over-half of treated probable genital TB cases provides preliminary evidence that best clinical practices can be utilized, but needs further confirmatory studies.  相似文献   
88.
In August 2012, the Centers for Disease Control and Prevention, in partnership with the Association of Maternal and Child Health Programs, convened a meeting of national subject matter experts to review key clinical elements of anthrax prevention and treatment for pregnant, postpartum, and lactating (P/PP/L) women. National experts in infectious disease, obstetrics, maternal fetal medicine, neonatology, pediatrics, and pharmacy attended the meeting, as did representatives from professional organizations and national, federal, state, and local agencies. The meeting addressed general principles of prevention and treatment for P/PP/L women, vaccines, antimicrobial prophylaxis and treatment, clinical considerations and critical care issues, antitoxin, delivery concerns, infection control measures, and communication. The purpose of this meeting summary is to provide updated clinical information to health care providers and public health professionals caring for P/PP/L women in the setting of a bioterrorist event involving anthrax.  相似文献   
89.
Where wildlife disease requires management, culling is frequently considered but not always effective. In the British Isles, control of cattle tuberculosis (TB) is hindered by infection in wild badger (Meles meles) populations. Large-scale badger culling can reduce the incidence of confirmed cattle TB, but these benefits are undermined by culling-induced changes in badger behavior (termed perturbation), which can increase transmission among badgers and from badgers to cattle. Test–vaccinate/remove (TVR) is a novel approach that entails testing individual badgers for infection, vaccinating test-negative animals, and killing test-positive animals. Imperfect capture success, diagnostic sensitivity, and vaccine effectiveness mean that TVR would be expected to leave some infected and some susceptible badgers in the population. Existing simulation models predict that TVR could reduce cattle TB if such small-scale culling causes no perturbation, but could increase cattle TB if considerable perturbation occurs. Using data from a long-term study, we show that past small-scale culling was significantly associated with four metrics of perturbation in badgers: expanded ranging, more frequent immigration, lower genetic relatedness, and elevated prevalence of Mycobacterium bovis, the causative agent of TB. Though we could not reject the hypothesis that culling up to three badgers per social group might avoid perturbation, we also could not reject the hypothesis that killing a single badger prompted detectable perturbation. When considered alongside existing model predictions, our findings suggest that implementation of TVR, scheduled for 2014, risks exacerbating the TB problem rather than controlling it. Ongoing illegal badger culling is likewise expected to increase cattle TB risks.Infectious diseases are often difficult to control where wildlife hosts contribute to pathogen persistence. Wildlife culling is a frequently considered control option, which is sometimes effective (1, 2), but often ineffective (36).In the United Kingdom, the cattle farming industry is seriously affected by bovine tuberculosis (TB) caused by Mycobacterium bovis (7). Selective culling of test-positive cattle has helped to eradicate TB across much of the developed world, but eradication from the United Kingdom is impeded by M. bovis infection in European badgers (Meles meles) (8), as well as by continued transmission among cattle (911). Transmission has also been documented among badgers (12), from cattle to badgers (13), and from badgers to cattle (14, 15). Because badgers are clearly a contributing factor to the UK’s TB problem, successive TB control policies have included culling of badgers (7, 8). To date, cattle controls have emphasized selective slaughter of test-positive animals, whereas badger culls have typically been nonselective, with no testing of live animals before culling (but see ref. 16).The impacts of nonselective badger culling on M. bovis transmission are well established. Such culling reduces badger density (17), but also promotes dispersal into the culled area (18) as well as expanding badger ranging in and around the areas where culls occurred (19). In Britain these behavioral changes—termed social perturbation—have been linked to increases in the proportion of badgers infected with M. bovis (13, 20), and reductions in the spatial clustering of infection (21). In cattle, the incidence of confirmed TB was reduced inside large culling areas where badger numbers were substantially suppressed by annual “proactive” culling. However, on adjoining unculled lands, and in areas receiving localized “reactive” culling, reductions in badger numbers were smaller, the incidence of confirmed cattle TB was elevated (14, 15, 2224), and spatial clustering of cattle infection was reduced (21).This propensity of nonselective badger culling to prompt social perturbation and hence increase disease transmission is a major constraint on its utility as a tool for controlling cattle TB. An alternative approach, first proposed in the 1980s, would be to target culling at test-positive badgers, just as current controls target test-positive cattle (16, 25). A further elaboration, termed test–vaccinate/remove (TVR), involves killing test-positive badgers while vaccinating test-negative badgers. A pilot TVR program is scheduled to take place across 100 sq km in Northern Ireland in 2014 (26).Selective culling approaches (such as TVR) are likely to remove relatively small numbers of badgers. First, constraints on capture success limit testing to 56–85% of the badger population (27, 28). Second, not all captured badgers will be infected with M. bovis: in the 10 initial proactive culls of the Randomized Badger Culling Trial (RBCT), 2–38% of badgers had infection detectable by bacterial culture at standard necropsy (29). Third, not all infected badgers are detectable by available live tests: the only available trap-side test detected 49% of badgers that were culture-positive at necropsy (30), and standard necropsy itself detected only 55% of infected badgers (31). This combination of imperfect capture success, low average infection prevalence, and imperfect test sensitivity means that the numbers of badgers to be killed by selective culling would probably be low, usually just one or two badgers within a social group (32). The same factors, combined with incomplete vaccine efficacy (33), mean that some infected and some susceptible badgers would be expected to remain despite implementation of TVR.Simulations indicate that the likely consequences of TVR for cattle TB control are highly sensitive to assumptions about whether culling small numbers of badgers prompts social perturbation (34, 35). Neither cage trapping for testing nor vaccination has been found to cause behavioral change. If the culling component of TVR likewise causes no perturbation, then TVR is predicted to reduce the prevalence of M. bovis infection in badgers and hence the incidence of cattle TB (34, 35). However, if TVR causes perturbation similar to that associated with past large- and small-scale culling, then it is projected to prompt sustained (34) or transient (35) increases in cattle TB. Unfortunately, it is not known which of these scenarios is more likely. Although the behavioral and epidemiological consequences of nonselective culling are relatively well understood, there have been no empirical studies of badgers’ behavioral responses to killing small numbers of animals per social group, as would occur under TVR and other forms of selective culling.In this paper, we use data from a large-scale study to assess whether killing small numbers of badgers would be expected to prompt social perturbation. We compare patterns of badger movement and M. bovis infection at the start of the RBCT (conducted 1998–2005) (14) with two indices of badger mortality. Our first measure, road density, provides an index of the numbers of badgers killed in road accidents (36), an important cause of badger mortality in Britain (37, 38). Our second measure is prior nonselective culling, conducted during the period 1986–1998 as small-scale badger removal operations (BROs), which typically targeted single farms (8). We hypothesized that high road densities and intense prior culling would each lead to expanded badger movement and elevated M. bovis prevalence. Further, we hypothesized that perturbation might be avoided if the number of badgers killed remained below a certain threshold, and sought to estimate this threshold.  相似文献   
90.

Objective

The Mycobacterium bovis Bacillus Calmette-Guerin (BCG) neonatal vaccination inhibits allergy-induced pathologic changes. However, the mechanisms underlying this process are unclear. This study aimed to investigate the role of interferon (IFN)-γ and interleukin (IL)-17 in the protective effects of the BCG neonatal vaccination on allergic pulmonary inflammation and airway hyperresponsiveness (AHR).

Methods

Wild type (WT)-neonate and IL-17 knock out (KO) neonate mice were vaccinated with BCG. A murine asthma model was developed by sensitization and then challenging with ovalbumin (OVA). Recombinant IL-17 or recombinant IFN-γ was delivered to the airway to overexpress IL-17 or IFN-γ. An anti-IFN-γ neutralizing antibody was used to block the effects of IFN-γ.

Results

We found exogenous IL-17 delivered to the airway reversed the anti-asthma effects of the neonatal BCG vaccination. BCG neonatal vaccination further reduced OVA-induced inflammation and AHR in IL-17 KO mice. Inhibition of IFN-γ in BCG neonatal vaccinated OVA-induced asthma model mice led to a further reduction in airway inflammation and AHR. In addition, airway inflammation and AHR were robust following treatment with exogenous IFN-γ. Neutralizing IL-17 was not sufficient to block OVA-induced airway inflammation and AHR. In IL-17 KO mice, airway inflammation and AHR did not occur following treatment with an anti-IFN-γ neutralizing antibody.

Conclusions

In an OVA-induced murine asthma model, inhibition of IFN-γ enhanced the anti-asthma effects of BCG neonatal vaccination.  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