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   1288262篇
  免费   93111篇
  国内免费   2040篇
耳鼻咽喉   18306篇
儿科学   42538篇
妇产科学   38001篇
基础医学   188395篇
口腔科学   35773篇
临床医学   109097篇
内科学   253983篇
皮肤病学   26830篇
神经病学   100500篇
特种医学   50398篇
外国民族医学   368篇
外科学   199121篇
综合类   26614篇
现状与发展   1篇
一般理论   303篇
预防医学   93264篇
眼科学   29259篇
药学   98551篇
  1篇
中国医学   2522篇
肿瘤学   69588篇
  2018年   12073篇
  2016年   10283篇
  2015年   11885篇
  2014年   16383篇
  2013年   24815篇
  2012年   34333篇
  2011年   36708篇
  2010年   21643篇
  2009年   20397篇
  2008年   35637篇
  2007年   38567篇
  2006年   39113篇
  2005年   38419篇
  2004年   36954篇
  2003年   35862篇
  2002年   35380篇
  2001年   58383篇
  2000年   59873篇
  1999年   50928篇
  1998年   14331篇
  1997年   12891篇
  1996年   13159篇
  1995年   12420篇
  1994年   11836篇
  1993年   10927篇
  1992年   41163篇
  1991年   40503篇
  1990年   40010篇
  1989年   38812篇
  1988年   36206篇
  1987年   35447篇
  1986年   33810篇
  1985年   32225篇
  1984年   23992篇
  1983年   20864篇
  1982年   12414篇
  1981年   10963篇
  1979年   22686篇
  1978年   15906篇
  1977年   13758篇
  1976年   12999篇
  1975年   14235篇
  1974年   16717篇
  1973年   16106篇
  1972年   15369篇
  1971年   14257篇
  1970年   13244篇
  1969年   12756篇
  1968年   12009篇
  1967年   10509篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
191.
Safety and efficacy of botulinum toxin type A following long-term use   总被引:2,自引:0,他引:2  
Botulinum toxin serotype A (BoNT-A) has long heritage of use leading to confidence in its safety and efficacy. The application of BoNT-A does not lead to persistent histological changes in the nerve terminal or the target muscle. Clinical trials defined the safety and tolerability profile of BoNT-A across common therapeutic indications and showed an incidence of adverse events of approximately 25% in the BoNT-A-treated group compared with 15% in the control group. Focal weakness was the only adverse event to occur more often following BoNT-A treatment. Long-term BoNT-A administration has been assessed in various treatment settings, with the level and duration of BoNT-A efficacy response being maintained over repeated rounds of injection with no major safety concerns. The treatment of children with cerebral palsy often require long-term, repeated, multimuscle BoNT-A injections that lead to the administration of comparably higher toxin doses. Despite the high total body doses used, their distribution over multiple muscles and injection sites means that systemic side effects are rare. Recent formulation changes have reduced the incidence of antibody development following treatment with BOTOX®. These findings show long-term BoNT-A treatment to be both safe and efficacious for a wide variety of indications.  相似文献   
192.
Is atrial fibrillation an inflammatory disorder?   总被引:2,自引:0,他引:2  
I read with great interest the excellent review on the influenceof inflammation in the pathogenesis of atrial fibrillation (AF)by Boos   相似文献   
193.
194.
The incidence of uterine cervical cancer has increased slightly in Western countries, with an increase in relatively young women. Overexpression of matrix metalloproteinases (MMPs)-2 and -9 has turned out as a prognostic factor in many cancers. We compared the expression of the proteins MMP-2 and MMP-9 in cervical primary tumors with clinical outcome and risk factors of cervical cancer. One hundred sixty-one patients with cervical cancer treated in Ume? University Hospital or Sahlgrenska University Hospital, Sweden, between 1991 and 1995 were included in the study. Paraffin-embedded tissue samples obtained prior to treatment were examined immunohistochemically by specific antibodies for MMP-2 and MMP-9. Forty-two percent of the tumors were intensively positive for MMP-2 and 31% for MMP-9. Nineteen percent of the samples were intensively positive for both proteinases and 47% negative or weak for both. Overexpression of MMP-2 seemed to predict unfavorable survival under Kaplan-Meier analysis and in the multivariate analysis. Early sexual activity and low parity seemed to correlate to overexpression of MMP-2. MMP-9 was not associated with survival or sexual behavior. Intensive MMP-9 was noted in grade 1 tumors. We conclude that MMP-2 and MMP-9 have different roles in uterine cervical cancer. MMP-2 could be associated with aggressive behavior, but MMP-9 expression diminishes in high-grade tumors.  相似文献   
195.
The main objectives of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) are to harmonise breakpoints for antimicrobial agents in Europe, and to act as the breakpoint committee for the European Medicines Agency (EMEA) during the registration of new antimicrobial agents. Detailed EUCAST procedures for harmonising and setting breakpoints for antimicrobial agents are available on the EUCAST website. Beginning with the current issue, a series of EUCAST Technical Notes will be published in CMI, based on the rationale documents produced by EUCAST for each of the antimicrobial agents studied, with the aim of highlighting important background information underlying decisions on breakpoints made by EUCAST.  相似文献   
196.
Uniparental isodisomy (iUPD) is a rare genetic condition caused by non-disjunction during meiosis that ultimately leads to a duplication of either the maternal or paternal chromosome in the affected individual. Two types of disorders can result, those due to imprinted genes and those due to homozygosity of recessive disease-causing mutations. Here, we describe the third known case of complete chromosome 4 iUPD of maternal origin. This condition became apparent during whole genome linkage studies of psychiatric disorders in the Portuguese population. The proband is an adult female with normal fertility and no major medical complaints, but a history of major depressive disorder and multiple suicide attempts. The proband's siblings and parents had normal chromosome 4 genotypes and no history of mood disturbance. A brief review of other studies lends support for the possibility that genes on chromosome 4 might confer risk for mood disorders. We conclude that chromosome 4 maternal uniparental disomy (UPD) is a rare disorder that may present with a major depressive phenotype. The lack of a common disease phenotype between this and two other cases of chromosome 4 iUPD [Lindenbaum et al. [1991] Am J Med Genet 49(Suppl 285):1582; Spena et al. [2004] Eur J Hum Genet 12:891-898) would suggest that there is no vital maternal gene imprinting on chromosome 4. However, since there is no reported case of paternal chromosome 4 UPD, paternal gene imprinting on chromosome 4 cannot be excluded.  相似文献   
197.
OBJECTIVES: To identify and describe current women's thoughts about the menopause, hormone treatment (HT) and perceptions about breast cancer. METHODS: Between December 2004 and January 2005, 4201 postmenopausal women in seven European countries were interviewed via a standardized computer-aided telephone interview protocol. RESULTS: Almost all women reported to have experienced climacteric symptoms, and 63% of the women rated them as being severe. Only 52% of women were aware of the benefits of HT for relief of climacteric symptoms. Although 84% felt that severe symptoms should be treated, only 40% had used HT at some point in time. Thirty-four percent of the women preferring treatment with natural products did so because of the risk of breast cancer associated with HT. HT was recognized by 59% of the women as one of the most important contributors to an increased breast cancer risk. Most women received their information about HT and breast cancer risk from the media. CONCLUSIONS: This European survey reveals that the majority of women experience climacteric symptoms but that their decision whether or not to use HT is highly dependent on their concern about breast cancer risk. An increase in knowledge of the benefits and risks of HT is required for women to make appropriate decisions about hormone use.  相似文献   
198.
199.
BACKGROUND: Arterial hypertension and postmenopausal reduction of estrogen levels may be involved in modifications of the stiffness of large arteries. OBJECTIVES: To evaluate the pulse-wave velocity (PWV) and indirectly the arterial stiffness in hypertensive postmenopausal women submitted to hormone therapy with estradiol alone or combined with norethisterone acetate. SUBJECTS: Forty-five hypertensive postmenopausal women were double-blindly, randomly assigned to three arms of treatment: placebo (group I); estradiol 2 mg/day (group II); or estradiol 2 mg/day and norethisterone acetate 1 mg/day (group III). METHODS: Arterial stiffness was assessed from PWV measurements of the common carotid and femoral arteries (CF-PWV) and the common carotid and radial arteries (CR-PWV) obtained using the automatic Complior(R) device, taken at baseline and after 12 weeks of treatment. RESULTS: After the 12-week treatment, values of CF-PWV and CR-PWV were not significantly different (p = 0.910 and p = 0.736, respectively) among the groups. Systolic blood pressure showed a positive correlation with CF-PWV in groups II and III (p = 0.02 and p < 0.001, respectively). CONCLUSIONS: PWV and arterial stiffness in postmenopausal hypertensive women did not reduce over a 12-week treatment with estradiol alone compared with the same period of treatment with estradiol combined with norethisterone acetate.  相似文献   
200.
The worldwide burden of hepatitis B mandates accurate and timely diagnosis of patients infected with the hepatitis B virus (HBV) and the use of treatment strategies derived from evidence-based guidelines. HBV is a DNA virus that produces a series of viral protein products circulating HBV DNA. Serologic and nucleic acid testing are critical to disease prevention and treatment objectives. Information from such testing helps determine patients' infectivity and immune status, appropriate monitoring strategies, and the efficacy of treatment, as well as providing data that contributes to a better understanding of the natural history and epidemiology of the disease. This article reviews the clinical use of state-of-the-art serologic and nucleic acid tests, including the relevance of hepatitis B e antigen and antibody and HBV DNA measurements as markers of disease activity. Viral load can be used to distinguish between active and inactive disease, define response to therapy, and detect the development of antiviral resistance. Some recent reports have suggested that high viral load is associated with poorer patient outcomes (eg, more rapid progression to cirrhosis and a higher incidence of hepatocellular carcinoma). Durable suppression of HBV DNA is evolving to become the primary goal of therapy, although all currently licensed medications have used histology as the primary end point of therapy. Suggested frequencies for HBV DNA monitoring are presented.  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