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   640篇
  免费   36篇
  国内免费   4篇
耳鼻咽喉   2篇
儿科学   18篇
妇产科学   3篇
基础医学   49篇
口腔科学   20篇
临床医学   98篇
内科学   135篇
皮肤病学   23篇
神经病学   6篇
特种医学   96篇
外科学   39篇
综合类   64篇
预防医学   54篇
眼科学   2篇
药学   28篇
  1篇
中国医学   19篇
肿瘤学   23篇
  2023年   3篇
  2022年   7篇
  2021年   10篇
  2020年   12篇
  2019年   10篇
  2018年   17篇
  2017年   8篇
  2016年   7篇
  2015年   33篇
  2014年   25篇
  2013年   33篇
  2012年   36篇
  2011年   33篇
  2010年   43篇
  2009年   32篇
  2008年   28篇
  2007年   28篇
  2006年   9篇
  2005年   10篇
  2004年   7篇
  2003年   14篇
  2002年   4篇
  2001年   8篇
  2000年   1篇
  1999年   4篇
  1998年   27篇
  1997年   23篇
  1996年   29篇
  1995年   23篇
  1994年   22篇
  1993年   14篇
  1992年   3篇
  1991年   1篇
  1990年   3篇
  1989年   14篇
  1988年   16篇
  1987年   11篇
  1986年   8篇
  1985年   12篇
  1984年   9篇
  1983年   6篇
  1982年   8篇
  1981年   3篇
  1980年   8篇
  1979年   1篇
  1978年   3篇
  1977年   2篇
  1976年   7篇
  1975年   3篇
  1954年   1篇
排序方式: 共有680条查询结果,搜索用时 31 毫秒
51.
淋巴靶向制剂——吸附抗癌药毫微粒活性炭的研究进展   总被引:12,自引:0,他引:12  
目的介绍新型淋巴靶向制剂———吸附抗癌药毫微粒活性炭的研究进展。方法依据近年来的文献 ,对活性炭的制备工艺及体内外性质等方面进行了综述。结果活性炭具有很强的吸附功能 ,普通市售活性炭仅用作脱色、吸附热原与除味等。以微粒球磨机为粉碎器械 ,可加工制备粒径达1 0 0nm左右的纳米炭微粒 ,具有优越的淋巴趋向性。结论吸附抗癌药毫微粒活性炭在临床治疗癌症方面具有良好的运用前景  相似文献   
52.
Eleven female patients with cervicogenic headache (mean age, 43 years; range, 25-59 years) have been examined with the pupillometer. The pupillary diameter was examined in the basal state (that is, the status before pharmacologic stimulation) and after topically administered tyramine (2%), phenylephrine (1%), and hydroxyamphetamine (1%). A total of 51 tests were performed, 35 in the asymptomatic period and 16 during pain attacks. In a control group consisting of 26 age-matched women a total of 39 tests were carried out. Before pharmacologic stimulation (that is, in the "basal state") the pupils were smaller in the asymptomatic (pain-free) period than during pain attacks in the patients and also as compared with that of control individuals. The anisocoria (the difference in pupillary size in the same individual) observed was not significantly different between the patient group and control individuals either in the basal state (before pharmacologic stimulation) or after pharmacologic stimulation. The mydriasis resulting from the instillation of the three sympathicomimetic drugs was symmetrical in both controls and patients both during and between the pain attacks. This finding is in clear contrast to what is found in cluster headache, in which there is a "Horner-like" syndrome on the symptomatic side. These two headaches thus seem to differ essentially with regard to this variable.  相似文献   
53.
54.
55.
56.
TA Lane  ; GE Lamkin 《Transfusion》1988,28(3):237-242
Granulocyte (PMN) concentrates collected for transfusion to septic, neutropenic patients are stored in the blood bank for various periods of time before they are given. Current methods of blood bank storage of PMN concentrates are associated with impaired in vitro PMN chemotaxis (CTX) and in vivo recovery and circulation kinetics after 24 hours of storage. This suggested the possibility that PMN may become hyperadherent during storage. To test this hypothesis, PMN concentrates were harvested and stored at both 22 and 6 degrees C and their adherence properties to relevant biologic surfaces, endothelial cell (EC) monolayers, and extracellular matrix (ECM) derived from endothelium were measured. Adherence was measured within 4 hours of collection and after 24 and 48 hours of storage. The aggregation properties of fresh and stored PMN were also studied. The adherence of fresh, unstimulated PMN to EC and ECM (31 +/- 5% and 34 +/- 4%, respectively) increased significantly after storage for 24 hours (EC = 41 +/- 8%; ECM = 43 +/- 4%) at 22 degrees C. F-Met-Leu-Phe (FMLP) stimulated the adherence of fresh PMN (EC = 37 +/- 4%; ECM = 42 +/- 4%; p less than 0.05). The adherence of PMN stored at 22 degrees C was further stimulated by FMLP (EC = 46 +/- 6%; ECM = 50 +/- 4%). PMN stored at 6 degrees C had significantly higher adherence than PMN stored at 22 degrees C, and the percentage of increase in adherence induced by FMLP was attenuated in PMN stored at 6 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
57.
Clinical measurement of swallowing in health and in neurogenic dysphagia   总被引:8,自引:0,他引:8  
We studied clinical features potentially related to dysphagia and three indices from a timed test of swallowing--average volume per swallow (ml), average time (s) per swallow and swallowing capacity (ml/s)--in 181 screened healthy adults and 30 patients with motor neurone disease (MND). In healthy adults, age, sex and height accounted for 44.3% and 55.6% of the variance of log average volume per swallow and log swallowing capacity, respectively. Symptoms and signs were more prevalent in the MND group and were associated with reduced swallowing capacity and reduced average volume per swallow; repeatability studies on these two indices in both groups showed that the median difference between the mean of two recordings on successive days and the mean of all recordings (6-15 over 3 days) was < 5% (maximum third quartile 12.8%, indices expressed as percent predicted according to age and sex). Using this simple bedside test, swallowing function can be quantified on a ratio scale and expressed as percent of that predicted by age and sex; such information may improve the predictive value of clinical assessment and provides a practical way of monitoring change in patients with dysphagia.   相似文献   
58.
Gender Differences in Patients With AVNRT. Introduction: The detailed electrophysiological characteristics of the gender differences associated with atrioventricular nodal reentrant tachycardia (AVNRT) have not been clarified. This study investigated the gender‐related electrophysiological differences in a large series of patients undergoing radiofrequency catheter ablation. Methods and Results: A total of 2,088 consecutive AVNRT patients (men/women 869/1,219) who underwent catheter ablation were enrolled in this study. We evaluated the gender differences in their electrophysiological characteristics. Women had a significantly younger age of onset, higher incidence of multiple jumps, shorter AH interval, atrial effective refractory period (ERP), anterograde fast pathway ERP, anterograde slow pathway ERP, and retrograde slow pathway ERP, and longer ventricular ERP than men. The incidence of baseline ventriculoatrial dissociation was lower in women than in men. Women needed less isoproterenol/atropine to induce AVNRT. No gender differences in the radiation exposure time, procedure time, complication rate, acute success rate, or second procedure rate were noted. Both typical and atypical AVNRT were more predominant in women. In the patients with atypical AVNRT, there was no significant gender difference in incidence of baseline ventriculoatrial dissociation; however, the retrograde slow pathway ERP was significantly shorter in women than in men. Women of premenopausal age (≤50 years old) had a significantly higher incidence of anterograde multiple jumps and a retrograde jump phenomenon, and a shorter anterograde slow pathway ERP and retrograde slow pathway ERP than those of women over 50 years old. Conclusion: Gender differences in the anterograde and retrograde AV nodal electrophysiology were noted in the patients with AVNRT. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1114‐1119)  相似文献   
59.
Unipolar Characteristics of CFAEs. Background: The noncontact mapping (NCM) system possesses the merit of global endocardial recording for unipolar and activation mapping. Objective: We aimed to evaluate the unipolar electrogram characteristics and activation pattern over the bipolar complex fractionated atrial electrogram (CFAE) sites during atrial fibrillation (AF). Methods: Twenty patients (age 55 ± 11 years old, 15 males) who underwent NCM and ablation of AF (paroxysmal/persistent = 13/7) were included. Both contact bipolar (32–300 Hz) and NCM virtual unipolar electrograms (0.5–300 Hz) were simultaneously recorded along with the activation pattern (total 223 sites, 11 ± 4 sites/patient). A CFAE was defined as a mean bipolar cycle length of ≤ 120 ms with an intervening isoelectric interval of more than 50 ms (Group 1A, n = 63, rapid repetitive CFAEs) or continuous fractionated activity (Group 1B, n = 59, continuous fractionated CFAEs), measured over a 7.2‐second duration. Group 2 consisted of those with a bipolar cycle length of more than 120 ms (n = 101). Results: The Group 1A CFAE sites exhibited a shorter unipolar electrogram cycle length (129 ± 11 vs 164 ± 20 ms, P < 0.001), and higher percentage of an S‐wave predominant pattern (QS or rS wave, 63 ± 13% vs 35 ± 13%, P < 0.001) than the Group 2 non‐CFAE sites. There was a linear correlation between the bipolar and unipolar cycle lengths (P < 0.001, R = 0.87). Most of the Group 1A CFAEs were located over arrhythmogenic pulmonary vein ostia or nonpulmonary vein ectopy with repetitive activations from those ectopies (62%) or the pivot points of the turning wavefronts (21%), whereas the Group 1B CFAEs exhibited a passive activation (44%) or slow conduction (31%). Conclusions: The bipolar repetitive and continuous fractionated CFAEs represented different activation patterns. The former was associated with an S wave predominant unipolar morphology which may represent an important focus for maintaining AF. (J Cardiovasc Electrophysiol, Vol. 21, pp. 640‐648, June 2010)  相似文献   
60.
目的:研究野茼蒿的挥发性成分。方法:用固相微萃取(solid-phase microextrations,SPME)和气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)联用仪对野茼蒿的挥发性成分进行测定。结果:从中共鉴定出37种化学成分。含量最多的3种成分是月桂烯(61.609%)、牛儿烯D(6.481%)、α-葎草烯(6.293%)。结论:茼蒿主要挥发性成分为烯烃。  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