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   675篇
  免费   38篇
  国内免费   20篇
耳鼻咽喉   2篇
儿科学   29篇
妇产科学   7篇
基础医学   48篇
口腔科学   26篇
临床医学   140篇
内科学   144篇
皮肤病学   2篇
神经病学   12篇
特种医学   164篇
外科学   51篇
综合类   24篇
预防医学   25篇
药学   25篇
肿瘤学   34篇
  2023年   6篇
  2022年   2篇
  2021年   10篇
  2020年   2篇
  2019年   3篇
  2018年   5篇
  2017年   6篇
  2016年   9篇
  2015年   5篇
  2014年   16篇
  2013年   25篇
  2012年   15篇
  2011年   25篇
  2010年   26篇
  2009年   44篇
  2008年   15篇
  2007年   15篇
  2006年   9篇
  2005年   13篇
  2004年   3篇
  2003年   13篇
  2002年   12篇
  2001年   18篇
  2000年   15篇
  1999年   10篇
  1998年   40篇
  1997年   38篇
  1996年   37篇
  1995年   35篇
  1994年   22篇
  1993年   25篇
  1992年   7篇
  1991年   5篇
  1990年   8篇
  1989年   25篇
  1988年   24篇
  1987年   15篇
  1986年   9篇
  1985年   16篇
  1984年   10篇
  1983年   8篇
  1982年   20篇
  1981年   13篇
  1980年   20篇
  1979年   4篇
  1978年   8篇
  1977年   11篇
  1976年   7篇
  1975年   3篇
  1974年   1篇
排序方式: 共有733条查询结果,搜索用时 31 毫秒
91.
The present study attempted to identify psychological differences among different headache diagnoses defined by IHS criteria as well as psychological differences by headache intensity and frequency. Differences between diagnostic categories reflected characteristics used to assign diagnoses, namely the constancy of pain and distracting behaviors of significant others due to isolating behavior from photophobia and phonophobia. A rating of headache intensity and frequency was a more powerful predictor of psychological ratings than diagnosis. Diagnosis was related to headache frequency but not intensity. The results suggest that a continuum diagnosis based on severity can be useful in conceptualizing headaches, and a dual-diagnostic system integrating headache characteristics with perceptions and coping ability would be helpful in determining treatment options.  相似文献   
92.
93.
MR imaging of ductal carcinoma in situ   总被引:15,自引:0,他引:15  
  相似文献   
94.
Hardy  DC; Murphy  WA; Siegel  BA; Reid  IR; Whyte  MP 《Radiology》1989,171(2):403-414
The radiologic studies of 38 essentially untreated adults with X-linked hypophosphatemia (XLH) were reviewed to determine the prevalence of radiologic features, to compare the findings in men and in women, and to elucidate the natural history of the disease by comparing the findings in young, intermediate-age, and older patients. Bone-reinforcement lines were common, but no characteristic mineral mass alteration was established. Looser zones were more prevalent in older subjects. Osteoarthritis was common, occurring in the ankles, knees, feet, sacroiliac joints, and wrists. Enthesopathy was infrequent in the younger group but was present in every member of the intermediate and older groups and was often accompanied by extra ossicles. Curvatures of the lower-extremity long bones were common in all age groups. Three new skeletal alterations in XLH were found to be common: flaring of the iliac wings, trapezoidal distal femoral condyles, and alterations in talar morphology, including shortening of the talar neck and flattening of the talar dome. Technetium-99m methylene diphosphonate scintigrams of 17 subjects were often abnormal, depicting bowing deformity and focal tracer accumulation in diaphyseal cortices and in periarticular and extraarticular regions. The mean metabolic index was moderately elevated (4.0). Both radiographic and scintigraphic findings were more severe in men, consistent with hemizygosity. The natural history of untreated XLH in both sexes is characterized by the development of a variety of age-related skeletal abnormalities during adulthood.  相似文献   
95.
96.
97.
98.
AIMS: To ascertain whether women who consulted their GP because they perceived themselves as at increased risk of familial breast cancer were indeed at increased risk, and to evaluate potential strategies for assessing genetic risk of breast cancer in general practice. METHODS: Sixty-seven out of 81 women who had consulted their GP for advice about their possible increased risk of developing breast cancer due to breast cancer in the family were interviewed. Familial breast cancer risk was assessed by a clinical geneticist. This assessment was compared with two recent guidelines for referral for genetic counselling. RESULTS: More than half (52%; n = 35) the women had a relative risk of two and over for developing breast cancer, while another half of these 35 (25%; n = 17) had a relative risk of three and over. All the women (n = 17) with a relative risk of three and over were identified by means of the two current guidelines for referral for genetic counselling, while more than half of the women (61%; n = 11) with a relative risk between two and three were identified. CONCLUSIONS: More than half the women concerned about their familial risk of breast cancer are indeed at increased risk of breast cancer. Current guidelines correctly identify women at high risk. However, doubts about the health gain and feasibility of referral warrant caution, and need further investigation.   相似文献   
99.
Lung lesions: correlation between viewing time and detection   总被引:2,自引:0,他引:2  
The influence of viewing time on the detectability of subtle and obvious lung cancers was studied. Frontal chest radiographs of 40 patients with subtle cancers, 40 patients with obvious cancers, and 40 healthy control subjects were shown to four observers for four different viewing times (0.25 second, 1 second, 4 seconds, and unlimited time). Receiver operating characteristic analysis was used to compare the detectability of lesions. Performance was degraded as viewing time decreased. The true-positive fractions for subtle and obvious cancers were 30% and 70% at 0.25 second and 74% and 98% at unlimited viewing time, respectively, for a given false-positive fraction of 20%. Thus, even with unlimited viewing time, the false-negative fraction for subtle cancers was 26%. The difference in detectability between subtle and obvious lung cancers was exaggerated at 1.0 second compared with 4 seconds and unlimited viewing time. The following conclusions were reached: (a) a substantial proportion of subtle lung lesions are missed, even with unlimited viewing time; (b) a large proportion of obvious lung cancers are detected with flash viewing; (c) the detectability of lesions decreases considerably as viewing time becomes less than 4 seconds; and (d) differences in detectability are exaggerated by short viewing times.  相似文献   
100.
Neurotensin (NT), an endogeneous tridecapeptide, produces significant hypothermia after intracisternal (i.c.) or intracerebroventricular (i.c.v.) administration in microgram quantities in a variety of laboratory animals. The present study sought to clarify the mechanism of the hypothermic action by utilizing pharmacological treatments which alter the function of brain neurotransmitter systems. Pretreatment of rats with anti-muscarinic (atropine), anti-noradrenergic (propranolol, a β-blocker; phenoxybenzamine, an α-blocker) or anti-opiate (naloxone) agents did not significantly alter NT-induced hypothermia. Similarly depletion of brain serotonin (5-HT) with parachlorophenylalanine did not affect NT-induced hypothermia. However, depletion of brain catecholamine content with 6-hydroxydopamine resulted in a significant potentiation of NT-induced hypothermia as did pretreatment with haloperidol, a dopamine (DA) receptor antagonist. Furthermore, in rats with selective depletions of brain DA, but not norepinephrine (NE), NT-induced hypothermia was significantly augmented. Thus an interaction between brain DA systems and NT appears likely.These data indicate that NT-induced hypothermia is not dependent on intact functional activity of NE, 5-HT, muscarinic ACh or endogeneous opiate systems but suggests interactions between brain DA circuits and NT. In other experiments, NT-induced hypothermia was found to be antagonized significantly by i.c. injection of thyrotropin-releasing hormone (TRH), but not by pretreatment withl-triiodothyroidectomy. Another endogeneous tripeptide (ProLeuGlyNH2, MIF-I) had no effect. Thyroidectomy (THX) significantly potentiated NT-induced hypothermia; NT administered i.c. significantly reduced the high serum TSH levels of THX rats. Thus, NT and TRH, two endogenous peptides, appear to be antagonists in certain systems.  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