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   12702篇
  免费   1231篇
  国内免费   36篇
耳鼻咽喉   219篇
儿科学   430篇
妇产科学   561篇
基础医学   1759篇
口腔科学   435篇
临床医学   1309篇
内科学   2772篇
皮肤病学   148篇
神经病学   1504篇
特种医学   489篇
外国民族医学   1篇
外科学   1735篇
综合类   222篇
一般理论   2篇
预防医学   752篇
眼科学   272篇
药学   679篇
中国医学   3篇
肿瘤学   677篇
  2021年   127篇
  2019年   133篇
  2018年   191篇
  2017年   175篇
  2016年   156篇
  2015年   203篇
  2014年   268篇
  2013年   422篇
  2012年   458篇
  2011年   472篇
  2010年   338篇
  2009年   366篇
  2008年   419篇
  2007年   479篇
  2006年   492篇
  2005年   460篇
  2004年   431篇
  2003年   388篇
  2002年   421篇
  2001年   378篇
  2000年   379篇
  1999年   307篇
  1998年   206篇
  1997年   198篇
  1996年   202篇
  1995年   151篇
  1994年   164篇
  1993年   127篇
  1992年   265篇
  1991年   275篇
  1990年   294篇
  1989年   311篇
  1988年   304篇
  1987年   297篇
  1986年   265篇
  1985年   298篇
  1984年   225篇
  1983年   173篇
  1982年   147篇
  1981年   147篇
  1979年   204篇
  1978年   163篇
  1977年   142篇
  1976年   121篇
  1975年   105篇
  1974年   159篇
  1973年   147篇
  1972年   117篇
  1971年   105篇
  1970年   108篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
OBJECTIVE: Although cutaneous leishmaniasis (CL) occurs mostly in the facial area, periocular involvement accounts for 2-5% of the facial lesions. CL lesions localized in the periocular region can easily be confused with various other diseases. The aim of this study was to examine the frequency of periocular involvement in CL in the Cukurova region of Turkey, as well as the clinical characteristics, diagnosis and methods of treatment of this disease. METHODS: Between December 1998 and December 2004, patients who were diagnosed with CL were evaluated prospectively with respect to periocular involvement. RESULTS: From the 2066 patients evaluated with CL, 2622 lesions were identified. In 59 (2.9%) of these patients, a total of 66 (2.5%) lesions were located in the periocular area. Thirty-two (48.5%) of these lesions were of the papular type, 15 (22.7%) the nodulo-ulcerative type, 10 (15.2%) the plaque type, and nine (13.6%) the nodular type. Dacryocystitis was identified in four patients with periocular involvement. Over the follow-up period, no ocular or periocular deformities or complications developed in these patients. CONCLUSION: Patients suspected of CL should be evaluated and treated early in the course of their disease to prevent any permanent ocular or periocular deformities.  相似文献   
52.
53.
The new thiazolyl peptide antibiotic MDL 62,879 (GE2270 A) showed excellent in vitro activity in testing against staphylococci and streptococci, with MIC90s ranging from 0.23 to 0.9 mg/l. It was very active againstClostridium difficile andPropionibacterium acnes (MIC90 0.06 mg/l in each case) and had variable activity againstBacteroides spp. MDL 62,879 had exceptionally good activity againstEnterococcus faecalis, including against a collection of high-level aminoglycoside-resistant isolates where it had an MIC90 of 0.047. The antibiotic was bacteriostatic for enterococcal isolates but bactericidal for a methicillin-resistant isolate ofStaphylococcus aureus.  相似文献   
54.
Occlusion of the vena cava has long been considered an insurmountable difficulty in patients needing liver transplantation. We report the case of a patient with a patent mesoatrial shunt and complete vena cava obstruction who underwent liver transplantation.  相似文献   
55.
Zolmitriptan (ZomigTM) is a 5HT1B/1D agonist which has the ability to cross the intact blood-brain barrier to access central as well as peripheral receptors. Because of the potential for central nervous system side effects, this randomized, double-blind, placebo-controlled, 6-period crossover study evaluated the effects of 2.5 and 5 mg doses of zolmitriptan on psychomotor performance and investigated any pharmacodynamic or pharmacokinetic interaction with diazepam. Twelve healthy volunteers received the following "treatments" as single doses: zolmitriptan 2.5 mg, zolmitriptan 5 mg, diazepam 10 mg, zolmitriptan 2.5 mg+diazepam 10 mg, zolmitriptan 5 mg+diazepam 10 mg and placebo. Pre-dose and at 1, 4, 8, and 24 h post-dose, the following validated battery of psychomotor tests was performed: Bond-Lader visual analogue scales (calmness, contentedness, and alertness factors), critical flicker fusion test, choice reaction time (recognition, motor, and total reaction times), finger-tapping test, number cancellation test and digit symbol substitution test. Plasma concentrations of zolmitriptan, its active metabolite, and diazepam and its active metabolites were measured at the same timepoints. Zolmitriptan 2.5 and 5 mg had no effect on psychomotor function when given alone. In contrast, diazepam 10 mg had profound effects, consistent with its sedative properties, but there was no synergism on concomitant administration of either dose of zolmitriptan. Plasma concentrations of zolmitriptan, diazepam, and their respective active metabolites were similar when the two drugs were given alone or in combination.  相似文献   
56.
Regulation of the immune system by neuroendocrine hormones is receiving increased attention. Prolactin, a hormone normally associated with lactation, has been shown recently to reconstitute immunosuppressed hypophysectomized rats. The present studies demonstrate that prolactin administration to normal mice results in a biphasic stimulation of antibody production to sheep red blood cells. While 100 and 200 micrograms bovine prolactin/animal stimulated antibody production, 400 micrograms had no effect. Potentiation of lectin-induced T-cell mitogenesis by prolactin was also biphasic. As the concentration of prolactin increased the incorporation of [3H]thymidine into the cells first increased and then decreased. Decreasing serum prolactin levels with the dopaminergic agonist bromocriptine resulted in a reduction of antibody titers to sheep erythrocytes and a modulation of thymic weight. These data show that prolactin can stimulate the immune system in a biphasic manner and that a reduction in the basal levels of this hormone results in an attenuated immune response.  相似文献   
57.
58.
59.
We developed a nursery Neurobiologic Risk Score (NBRS) based on potential mechanisms of brain cell injury in preterm infants and correlated it with developmental outcome at the corrected ages of 6, 15, and 24 months. The NBRS was determined at 2 weeks of age and at the time of discharge from intensive care in 58 preterm infants with birth weights less than or equal to 1500 gm. The NBRS correlated significantly with the Bayley Scales of Infant Development, Mental Development Index (MDI) (r = -0.61 to -0.40) and Psychomotor Development Index (PDI) (r = -0.59 to -0.46), and with abnormal neurologic examination findings (r = 0.59 to 0.73) at the three testing periods. Although 12 of the 13 items composing the NBRS individually correlated with one or more outcome variables, seven items (infection, blood pH, seizures, intraventricular hemorrhage, assisted ventilation, periventricular leukomalacia, and hypoglycemia) accounted for almost all of the explained variance. Logistic regression of individual items demonstrated intraventricular hemorrhage to be the most important item for predicting the MDI at 24 months; pH was the most influential item for predicting the PDI at every testing period. A shorter, revised NBRS that included only the seven significant items demonstrated as strong a correlation with developmental outcome as the original NBRS. A revised 2-week score of greater than or equal to 5 or a discharge score of greater than or equal to 6 demonstrated 100% specificity and had a 100% positive predictive value for an abnormal outcome at 24 months of age in this group of infants. We conclude that the NBRS identifies during the intensive care nursery stay those infants at highest risk for an abnormal outcome related to nursery events. In addition, analysis of NBRS items provides insight into the relative importance of individual factors for influencing mental, motor, and neurologic outcome.  相似文献   
60.
OBJECTIVES: Using two existing ethnographic studies of drug-involved adults, this study evaluates the association between child-abuse victimization and levels of involvement in inhalant use. METHODS: Historical accounts of childhood exposure to physical or sexual abuse were compared among nonusers of inhalants (n = 197), light inhalant users (n = 64), and heavy inhalant users (n = 24). Crude and adjusted odds ratios were used to compare informants with no history of inhalant use with those having a history of light inhalant use and those having a history of heavy inhalant use. RESULTS: Heavy inhalant use was associated with history of any child abuse (adjusted odds ratio [OR] = 4.6) and physical abuse (adjusted OR = 3.8). Light inhalant use showed no association with child-abuse history. CONCLUSIONS: Child abuse may be an important correlate of extensive involvement in inhalant use. The findings invite speculation with respect to a hypothetical causal role for child abuse in the etiology of inhalant use. The lack of support for causality in this study underscores the need for replication and more carefully designed longitudinal research.  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