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   81759篇
  免费   6697篇
  国内免费   3533篇
耳鼻咽喉   1347篇
儿科学   1107篇
妇产科学   1021篇
基础医学   11724篇
口腔科学   1383篇
临床医学   8872篇
内科学   14771篇
皮肤病学   1864篇
神经病学   5416篇
特种医学   4498篇
外国民族医学   21篇
外科学   9577篇
综合类   6458篇
现状与发展   13篇
一般理论   21篇
预防医学   4090篇
眼科学   1993篇
药学   7739篇
  38篇
中国医学   2774篇
肿瘤学   7262篇
  2024年   190篇
  2023年   1041篇
  2022年   2714篇
  2021年   3916篇
  2020年   2677篇
  2019年   2694篇
  2018年   2890篇
  2017年   2496篇
  2016年   2841篇
  2015年   4084篇
  2014年   4724篇
  2013年   4756篇
  2012年   6830篇
  2011年   7011篇
  2010年   4405篇
  2009年   3516篇
  2008年   4605篇
  2007年   4433篇
  2006年   4093篇
  2005年   3775篇
  2004年   2902篇
  2003年   2599篇
  2002年   2217篇
  2001年   1434篇
  2000年   1405篇
  1999年   1360篇
  1998年   754篇
  1997年   729篇
  1996年   563篇
  1995年   489篇
  1994年   430篇
  1993年   270篇
  1992年   430篇
  1991年   375篇
  1990年   322篇
  1989年   298篇
  1988年   288篇
  1987年   241篇
  1986年   203篇
  1985年   149篇
  1984年   101篇
  1983年   108篇
  1982年   52篇
  1981年   53篇
  1980年   43篇
  1979年   65篇
  1978年   49篇
  1977年   51篇
  1976年   46篇
  1974年   39篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
BACKGROUND CONTEXT: Spinal manipulation (SM) is a form of manual therapy used clinically to treat patients with low back and neck pain. The most common form of this maneuver is characterized as a high-velocity (duration <150 ms), low-amplitude (segmental translation <2 mm, rotation <4 degrees , and applied force 220-889 N) impulse thrust (high-velocity, low-amplitude spinal manipulation [HVLA-SM]). Clinical skill in applying an HVLA-SM lies in the practitioner's ability to control the duration and magnitude of the load (ie, the rate of loading), the direction in which the load is applied, and the contact point at which the load is applied. Control over its mechanical delivery is presumably related to its clinical effects. Biomechanical changes evoked by an HVLA-SM are thought to have physiological consequences caused, at least in part, by changes in sensory signaling from paraspinal tissues. PURPOSE: If activation of afferent pathways does contribute to the effects of an HVLA-SM, it seems reasonable to anticipate that neural discharge might increase or decrease in a nonlinear fashion as the thrust duration approaches a threshold value. We hypothesized that the relationship between the duration of an impulsive thrust to a vertebra and paraspinal muscle spindle discharge would be nonlinear with an inflection near the duration of an HVLA-SM delivered clinically (<150 ms). In addition, we anticipated that muscle spindle discharge would be more sensitive to larger amplitude thrusts. STUDY DESIGN/SETTING: A neurophysiological study of spinal manipulation using the lumbar spine of a feline model. METHODS: Impulse thrusts (duration: 12.5, 25, 50, 100, 200, and 400 ms; amplitude 1 or 2 mm posterior to anterior) were applied to the spinous process of the L6 vertebra of deeply anesthetized cats while recording single unit activity from dorsal root filaments of muscle spindle afferents innervating the lumbar paraspinal muscles. A feedback motor was used in displacement control mode to deliver the impulse thrusts. The motor's drive arm was securely attached to the L6 spinous process via a forceps. RESULTS: As thrust duration became shorter, the discharge of the lumbar paraspinal muscle spindles increased in a curvilinear fashion. A concave-up inflection occurred near the 100-ms duration eliciting both a higher frequency discharge compared with the longer durations and a substantially faster rate of change as thrust duration was shortened. This pattern was evident in paraspinal afferents with receptive fields both close and far from the midline. Paradoxically, spindle afferents were almost twice as sensitive to the 1-mm compared with the 2-mm amplitude thrust (6.2 vs. 3.3 spikes/s/mm/s). This latter finding may be related to the small versus large signal range properties of muscle spindles. CONCLUSIONS: The results indicate that the duration and amplitude of a spinal manipulation elicit a pattern of discharge from paraspinal muscle spindles different from slower mechanical inputs. Clinically, these parameters may be important determinants of an HVLA-SM's therapeutic benefit.  相似文献   
12.
目的 合理应用影像学检查,探讨腰腿痛的病因诊断,为临床治疗提供依据.方法 对38例腰腿痛患者进行随访,观察普通照片后经CT、MRI及B超等复查的最后诊断,对比进行分析.结果 单纯普通照片对椎间盘脱出、椎管狭窄、骶部硬膜外囊肿、股骨头无菌坏死、梨状肌损伤等疾病缺乏直接征象,不能作为诊断依据.结论 应用CT、MRI现代影像技术,同时借助B超、肌电图等相关检查,是确诊腰腿痛病因的有效方法.  相似文献   
13.
14.
目的 对比分析食管癌病例组与对照组血缘亲属食管癌患病风险,并了解食管癌家族中危险亲属人群患病的新线索.方法 采用病例对照研究方法 ,对食管癌病例组及对照组各720例进行逐层分析,以比较两组各血缘亲属父系、母系食管癌患病危险度(OR)的大小及差异.结果 (1)病例组Ⅰ级亲属食管癌患病危险度(1.34%~2.24%)显著高于对照组(0.78%~1.21%)(P<0.01);Ⅰ级亲属中病例组父母亲食管癌患病危险度为6.11%,显著高于对照组父母亲食管癌患病危险度2.97%(P<0O01).(2)以血缘亲属中父系和母系亲属逐层分析可见,病例组父系食管癌患病危险度(0.87%~1.01%)与母系患病危险度(0.50%~0.79%)均显著高于对照组父系食管癌患病危险度(0.53%~0.65%)与母系患病危险度(0.38%~0.47%)(P<0.05).进一步分析显示,病例组父系中男性亲属与母系中女性亲属,即父系中祖父、父亲、叔伯食管癌患病危险度为2.68%与母系中外祖母、母亲、姨的食管癌患病危险度1.91%均显著高于对照组父系中男性亲属食管癌患病危险度1.50%与母系中女性亲属食管癌患病危险度0.92%(P<0.01).结论 山西省食管癌患者血缘亲属发病危险主要是父亲及其兄弟、母亲及其姐妹,其下代患食管癌风险要大.  相似文献   
15.
试析陆懋修从阳明论治温病之特色   总被引:1,自引:0,他引:1  
陆懋修(1818-1886),又名免研,字九芝,号江左下工,又号林屋山人,江苏元和(今江苏吴县)人,为清代后期著名的医学家。陆氏出身于官宦之家,儒医兼通,陆氏秉承家学,对先人的医学成就颇为敬重。他曾三十余年坚持潜心研究《内经》、《伤寒》等医学经典著作,终于贯通医理而成为一代名医。陆氏一生博览群书之余,著述不断,  相似文献   
16.
17.
BACKGROUND: Dialysis patient mortality remains high, and this high mortality may be due to many factors. In peritoneal dialysis (PD) patients, old age, co-morbid diseases, malnutrition, low residual renal function (RRF) and a high peritoneal transport rate have been shown to influence survival, but the relative importance of these factors may differ between different patient populations. Besides, centre practice patterns may differ between centres and may influence patient survival. In addition, the literature suggests that dialysis patient survival may be better in Asian than in Caucasian patients. METHODS: The influence of centre and patient characteristics on patient survival was investigated in 132 Korean and 106 Swedish incident PD patients, who underwent initial biochemical measurements and assessment of adequacy of dialysis, nutritional status, RRF and peritoneal transport characteristics. RESULTS: At the start of PD, Korean patients had a higher prevalence of diabetes, peritoneal Kt/V(urea), peritoneal creatinine clearance and peritoneal fluid removal, and lower body mass index, RRF and dialysate to plasma creatinine concentration ratio (D/P Cr) compared with Swedish patients. Significantly more patients from Korea were placed on temporary haemodialysis before PD (100 out of 132) when compared with Swedish patients (21 out of 106). During the follow-up, there was a significantly higher rate of transfer to other units in Korea and a significantly higher rate of kidney transplantation in Sweden. On Kaplan-Meier analysis, overall patient survival did not differ and relative risk for death was also not different between the two centres even after adjustment for age, diabetes, cardiovascular disease, RRF and D/P Cr. On Cox proportional hazards multivariate analysis, age, diabetes, RRF and D/P Cr were found to be independent predictors of mortality in the combined cohort of patients. While age, diabetes and D/P Cr were independent predictors of mortality in Korean patients, age and RRF independently predicted mortality in Swedish patients. CONCLUSION: Although there were significant differences in centre and patient characteristics, we were unable to confirm a survival advantage for Korean over Swedish PD patients. The results of this study suggest that the reported difference in survival between Asian and Caucasian dialysis patients may have been due, in part, to differences in centre and patient characteristics rather than to race as such. The genetic influence on patient characteristics remains, however, to be elucidated.  相似文献   
18.
Cooking processes that gelatinize granules or disrupt structure might increase the glucose and insulin responses because a disruption of the structure of starch by gelatinization increases its availability for digestion and absorption in the small intestine. We hypothesized that the uncooked form of rice, which has a relatively low degree of gelatinization even though in powder form, would result in lower metabolic glucose and insulin responses compared with cooked rice (CR). To assess the effects of the gelatinization of rice on metabolic response of glucose and insulin, we investigated the glucose and insulin responses to 3 rice meals of different gelatinization degree in female college students (n = 12): CR (76.9% gelatinized), uncooked rice powder (UP; 3.5% gelatinized), and uncooked freeze-dried rice powder (UFP; 5.4% gelatinized). Uncooked rice powders (UP and UFP) induced lower glucose and insulin responses compared with CR. The relatively low gelatinization degree of UPs resulted in low metabolic responses in terms of the glycemic index (CR: 72.4% vs UP: 49.7%, UFP: 59.8%) and insulin index (CR: 94.8% vs UP: 74.4%, UFP: 68.0%). In summary, UPs that were less gelatinized than CR induced low postprandial glucose and insulin responses.  相似文献   
19.
COPD机械通气病人下呼吸道感染致病菌分布特点   总被引:1,自引:0,他引:1  
①目的 探讨慢性阻塞性肺病(COPD)病人机械通气后下呼吸道感染致病菌的特点。②方法 取32例COPD并发呼吸衰竭行机械通气病人下呼吸道分泌物做痰细菌学培养,同时做药物敏感试验。③结果 32例病人共分离出菌株76株,阳性率71.7%,其中混合感染10例次。其中革兰阴性杆菌(GNB)58株,占76.3%;阳性球菌10株,占13.2%;真菌8株,占10.5%。常见致病菌以铜绿假单胞菌、鲍曼不动杆菌和肺炎杆菌为主,GNB中铜绿假单胞菌和不动杆菌的耐药率高。④结论 COPD应用机械通气病人下呼吸道感染以革兰阴性杆菌为主,耐药性高。  相似文献   
20.
目前,冠状动脉造影已成为诊断冠心病,明确冠状动脉狭窄部位、程度的重要方法,对冠心病的诊断可达定量水平,为估计病人预后、决定药物使用及介入性治疗提供了更为确切的指标。由于介入性诊治属有创性,存在一定的风险,且术后需卧床制动,因此,绝大多数病人对该术存在担心恐惧等心理,加之术中、术后所承受的不适感觉,在很大程度上影响着该术的成功及病情变化,为减轻病人恐惧与担心,增加手术的成功率,认真做好病人的心理护理就显得尤为重要。自2000年6月我科开展冠状动脉介入性诊治护理以来,对病人心理特征不断进行观察分析,现将其总结如下。  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