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   732篇
  免费   45篇
  国内免费   96篇
耳鼻咽喉   3篇
儿科学   39篇
基础医学   84篇
口腔科学   25篇
临床医学   123篇
内科学   178篇
皮肤病学   8篇
神经病学   39篇
特种医学   110篇
外科学   61篇
综合类   36篇
预防医学   37篇
眼科学   15篇
药学   82篇
中国医学   2篇
肿瘤学   31篇
  2023年   3篇
  2021年   9篇
  2020年   6篇
  2019年   7篇
  2018年   4篇
  2017年   8篇
  2016年   9篇
  2015年   8篇
  2014年   13篇
  2013年   28篇
  2012年   19篇
  2011年   19篇
  2010年   37篇
  2009年   27篇
  2008年   22篇
  2007年   72篇
  2006年   27篇
  2005年   34篇
  2004年   15篇
  2003年   20篇
  2002年   13篇
  2001年   22篇
  2000年   12篇
  1999年   14篇
  1998年   41篇
  1997年   39篇
  1996年   31篇
  1995年   31篇
  1994年   30篇
  1993年   39篇
  1992年   9篇
  1991年   15篇
  1990年   18篇
  1989年   28篇
  1988年   26篇
  1987年   21篇
  1986年   19篇
  1985年   15篇
  1984年   11篇
  1983年   4篇
  1982年   9篇
  1981年   5篇
  1980年   10篇
  1979年   5篇
  1978年   3篇
  1977年   7篇
  1976年   5篇
  1975年   1篇
  1967年   1篇
  1966年   1篇
排序方式: 共有873条查询结果,搜索用时 15 毫秒
51.
52.
Cemento-ossifying fibroma presents with ophthalmic symptoms and signs rarely. We report the clinical and pathological findings in a case of cemento-ossifying fibroma of the right maxilla with extension into the orbital floor causing intermittent vertical diplopia, proptosis, and upward displacement of the globe. Compression of the nasolacrimal duct produced epiphora early in the course of the disease. Fibrous dysplasia has often been diagnosed in other cases of benign monostotic fibro-osseous conditions. Ossifying fibroma is easily confused with fibrous dysplasia. The histopathological difference between the two lesions is described.  相似文献   
53.
Cytotoxic T lymphocytes (CTL) are critical for control of lentiviruses, including equine infectious anemia virus (EIAV). Measurement of equine CTL responses has relied on chromium-release assays, which do not allow accurate quantitation. Recently, the equine MHC class I molecule 7-6, associated with the ELA-A1 haplotype, was shown to present both the Gag-GW12 and Env-RW12 EIAV CTL epitopes. In this study, 7-6/Gag-GW12 and 7-6/Env-RW12 MHC class I/peptide tetrameric complexes were constructed and used to analyze Gag-GW12- and Env-RW12-specific CTL responses in two EIAV-infected horses (A2164 and A2171). Gag-GW12 and Env-RW12 tetramer-positive CD8+ cells were identified in nonstimulated peripheral blood mononuclear cells as early as 14 days post-EIAV inoculation, and frequencies of tetramer-positive cells ranged from 0.4% to 6.7% of nonstimulated peripheral blood CD8+ cells during the 127-day study period. Although both horses terminated the initial viremic peak, only horse A2171 effectively controlled viral load. Neutralizing antibody was present during the initial control of viral load in both horses, but the ability to maintain control correlated with Gag-GW12-specific CD8+ cells in A2171. Despite Env-RW12 dominance, Env-RW12 escape viral variants were identified in both horses and there was no correlation between Env-RW12-specific CD8+ cells and control of viral load. Although Gag-GW12 CTL escape did not occur, a Gag-GW12 epitope variant arose in A2164 that was recognized less efficiently than the original epitope. These data indicate that tetramers are useful for identification and quantitation of CTL responses in horses, and suggest that the observed control of EIAV replication and clinical disease was associated with sustained CTL recognition of Gag-specific epitopes.  相似文献   
54.
55.
A 55-year-old woman who underwent orbital fat excision for cosmesis was incidentally found to have an isolated orbital cysticercus identified by histopathologic examination. The ensuing workup was negative for disseminated cysticercal infection and further treatment was deferred. Although uncommon, orbital cysticercosis should be considered in the differential diagnosis of an asymptomatic orbital mass. Symptomatic orbital myocysticercosis has been effectively treated with albendazole at a dosage of 30 mg/kg for 15 days combined with simultaneous low-dose steroids.  相似文献   
56.
BACKGROUND: Because apomorphine is a dopamine agonist that acts on areas of the central nervous system believed to mediate penile erection, its use in erectile dysfunction (ED) has been investigated. However, it also produces nausea by dopamine-receptor stimulation of the chemotrigger zone in the brain. Therefore, a low plasma concentration, achieved rapidly, would be selective for the desired erectile response but would be below the dopamine threshold for nausea. OBJECTIVE: We evaluated the efficacy and tolerability of a dose-optimized regimen of a sublingual formulation of apomorphine (apomorphine SL) in the treatment of ED. METHODS: This was a multicenter, open-label, uncontrolled, Phase III dose-optimization study of apomorphine SL in heterosexual men with ED. The 2-week screening period, during which baseline severity of ED was determined using the International Index of Erectile Function, was followed by a 3-week dose-optimization period beginning at a dose of 2 mg. Patients were to make at least 2 attempts at intercourse per week throughout the study, placing 1 apomorphine tablet under the tongue beforehand. At the end of the first week, the dose could be increased to 3 mg at the discretion of the investigator; at the end of the second week, the dose could be increased to a maximum of 4 mg or decreased as needed. In the following 4-week treatment period, patients took their individual optimal doses. The primary efficacy variable was the percentage of attempts resulting in erections firm enough for intercourse, as assessed by investigators' review of data from patients' diaries. Secondary variables included the percentage of attempts resulting in successful intercourse, time to erection, and duration of erection. Information about adverse events, including their severity and relation to treatment, was determined on the basis of direct questioning, spontaneous reports, and review of patient diaries. RESULTS: The study enrolled 849 heterosexual men whose ages ranged from 31 to 78 years (mean, 58.1 years). They had a mean 5.7-year history of ED of varbus causes. ED was mild in 11.5% of the men, moderate in 23.8 c, and severe in 48.1%. When results of the last 8 attempts were pooled, representing the period during which patients were taking their optimal doses of apomorphine SL, the mean percentage of attempts resulting in erections firm enough for intercourse was 39.4%, compared with 13.1% at baseline; attempts resulting in intercourse increased from a mean of 12.7% at baseline to 38.3% with treatment. The average median time to erection was 23 minutes, and the average median duration of erection was 13 minutes. Nausea, the most common treatment-related adverse event (11.7%). was dose related and diminished with continued dosing. One patient had a single syncopal episode that was judged to be related to apomorphine SL. CONCLUSIONS: In the present study, a dose-optimization regimen of apomorphine SL-with dosing initiated at 2 mg and adjusted up to a maximum of 4 mg as needed-was effective and well tolerated in the treatment of ED, regardless of its cause or severity.  相似文献   
57.
Background: An outbreak of food poisoning in a military establishment mess was investigated and remedial measures suggested.  相似文献   
58.
Meningitis is the most common serious manifestation of infection of the central nervous system. Inflammatory involvement of the subarachnoid space with meningeal irritation leads to the classical triad of headache, fever, and meningism, and to a pleocytosis of the cerebrospinal fluid (CSF). Meningitis is clinically categorized into an acute and chronic disease based on the acuity of symptoms. Acute meningitis develops over hours to days, while in chronic meningitis symptoms evolve over days or even weeks. Aseptic meningitis, in which no bacterial pathogen can be isolated by routine cultures, can mimic bacterial meningitis, but the disease has a much more favorable prognosis. Many cases of aseptic meningitis are caused by viruses, primarily enteroviruses, but bacteria and noninfectious etiologies also cause meningitis with negative cultures. Symptoms of meningeal inflammation with CSF pleocytosis that persist for more than 4 weeks define the chronic meningitis syndrome. The diagnosis is based on the patient history, clinical evidence of meningitis, CSF examination, and often imaging studies. The differential diagnosis is broad, and the predominant CSF cell type can provide clues as to the underlying disease. Empiric therapy is primarily based on the age of the patient, with modifications if there are positive findings on CSF gram stain or if the patient presents with special risk factors. In patients with chronic meningitis, a definite diagnosis is often not available or delayed for days, in which case empiric therapy may have to be initiated. It is important to cover the treatable causes of meningitis, for which the outcome is poor if treatment is delayed.  相似文献   
59.
高效液相色谱法测定寒痹停片中士的宁含量   总被引:6,自引:0,他引:6  
目的:建立用HPLC测定寒痹停片中士的含量的方法。方法:氰基柱;流动相-甲醇-水-三乙胺-乙酸(9800:155:15:30);紫外检测波长254nm。结果:在4~20ug/ml范围内,标准曲线回归方程为:Y=-2803+8967x(r=0.9997),RSD=1.65%?加样回收率的平均值为99.82%。结论:实验表明,这是一个适用于生产控制和产品质量检验的简单、快速、准确的方法。  相似文献   
60.
黄柏及中成药中小檗碱和巴马亭的高效液相色谱法测定   总被引:6,自引:0,他引:6  
本文以正相高效液相色谱法,用窗口图解技术对色谱条件进行了优化。对黄柏及其中成药中的有效成分——小檗碱、巴马亭的提取、测定条件、标准曲线进行了研究。并对两种含黄柏的中成药样品进行了分析。其中小檗碱的回收率均在97%以上,巴马亭的回收率均在96%以上。  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