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   2421580篇
  免费   197946篇
  国内免费   4406篇
耳鼻咽喉   34933篇
儿科学   73888篇
妇产科学   63814篇
基础医学   340716篇
口腔科学   68629篇
临床医学   220390篇
内科学   477751篇
皮肤病学   48864篇
神经病学   205492篇
特种医学   97516篇
外国民族医学   886篇
外科学   368110篇
综合类   56826篇
现状与发展   1篇
一般理论   1026篇
预防医学   194411篇
眼科学   56552篇
药学   180263篇
  7篇
中国医学   4401篇
肿瘤学   129456篇
  2018年   25271篇
  2017年   19565篇
  2016年   21460篇
  2015年   24271篇
  2014年   34929篇
  2013年   52898篇
  2012年   71910篇
  2011年   75748篇
  2010年   44373篇
  2009年   42637篇
  2008年   71935篇
  2007年   76354篇
  2006年   77149篇
  2005年   75196篇
  2004年   72356篇
  2003年   69948篇
  2002年   69008篇
  2001年   112878篇
  2000年   116923篇
  1999年   98802篇
  1998年   28425篇
  1997年   26006篇
  1996年   25872篇
  1995年   25032篇
  1994年   23517篇
  1993年   21868篇
  1992年   79700篇
  1991年   76650篇
  1990年   73818篇
  1989年   71065篇
  1988年   66079篇
  1987年   65025篇
  1986年   61527篇
  1985年   58634篇
  1984年   44461篇
  1983年   37905篇
  1982年   23197篇
  1981年   20589篇
  1980年   19267篇
  1979年   41436篇
  1978年   29116篇
  1977年   24483篇
  1976年   22907篇
  1975年   24030篇
  1974年   29718篇
  1973年   28116篇
  1972年   26271篇
  1971年   24197篇
  1970年   22792篇
  1969年   21131篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Relatives of 22 schizotypal probands were evaluated for lifetime psychiatric diagnoses. Forty-four (N = 44) of the 97 available relatives were interviewed directly using the Diagnostic Interview Schedule. The rates of psychiatric diagnoses were compared with those of sixty-six (N = 66) of 140 relatives of 30 depressed patients. Family history of mental illness was ascertained by the informant method on the remainder of relatives of both proband groups. The rate of depression found in the relatives of schizotypal patients was 52% in those directly interviewed and 25.7% when informants' reports on unavailable relatives are pooled with direct interview data. These rates were not significantly higher than those found for the relatives of depressed probands (34.8% by direct interview and 21% including reports from informants). The high rates of depression in the relatives of schizotypal probands may indicate that schizotypal personality is associated with affective disorder and not only with schizophrenia. However, the high rates may be due to the presence of depressive character traits in relatives, which inflate the rates of dysthymic disorder and other chronic depressive disorders in the relatives of borderline patients.  相似文献   
992.
993.
During 1983 and 1984, 1305 patients underwent 1,400 pulmonary artery (PA) catheterizations. Successful placement was achieved in 1397 (99.6%) of 1,403 attempts. The catheters were inserted via the right internal jugular vein on 1364 occasions. The median duration of monitoring was 28 h with a range from 3 to 220 h. Central venous puncture complications included carotid artery puncture in 67 instances (4.8%) and pneumothorax in one patient. Insertion of the catheters was associated with supraventricular arrhythmias on 11 occasions, ventricular arrhythmias on 930 (66.4%), right bundle branch block on two and a total heart block on one occasion. Eighteen (2.3%) of the 794 cultured catheter tips were positive. An in situ time of more than 72 h was associated with a significantly higher percentage (7.2%) of positive tip cultures compared with an in situ time of less than 72 h (P less than 0.01). Repeated PA catheterization was not associated with significantly more complications than the initial catheterization. The results show that monitoring with a PA catheter in cardiac surgical patients is associated with a low incidence of morbidity.  相似文献   
994.
995.
996.
997.
Immunocytochemical methods have been used to examine the localisation of 3 neurofilament proteins and the calcium binding protein, calbindin D28k, in whole mount preparations of the submucous plexus in the Wistar rat. Neurofilament-M (160 kDA protein) was present in 40% of the submucosal neurons, staining fine filaments in the soma and the axonal processes. Calbindin D28k was present in 40% of the submucosal neurons staining both the soma and nerves within the plexus. The neurofilament proteins and calbindin D28k were never observed within the same neurons. Neurofilament-M was co-localised with substance P and calcitonin gene-related peptide but not somatostatin or the other neuropeptides investigated. Calbindib D28k was co-localised with vasoactive intestinal polypeptide and neuropeptide Y. Galanin- and somatostatin-immunoreactive neurons did not contain either the neurofilament proteins or calbindin D28k. The results demonstrate the presence of subsets of submucosal neurons that can be distinguished by the presence of neurofilament-M or calbinsin D28k.  相似文献   
998.
Behavioral state-specific changes in human hippocampal theta activity   总被引:1,自引:0,他引:1  
Although there has been extensive examination of the behavioral and physiologic correlates of hippocampal theta activity in animals, the human literature consists of a single case study. We investigated the differential effects of four behavioral states on human hippocampal theta activity in 16 epilepsy surgery patients. Behavioral conditions included resting eyes closed (RC), resting eyes open (RO), eyes open with auditory word activation (AW), and eyes open with visuospatial activation (VS). Hippocampal theta activity decreased during both RO and VS compared to both RC and AW. There were reciprocal changes in delta activity. Comparisons of RO to VS and of RC to AW were nonsignificant. The results demonstrate state-specific changes in human hippocampal theta and are consistent with the animal literature that relates hippocampal theta to sensorimotor integration and forebrain volitional mechanisms.  相似文献   
999.
We have succeeded in recording short and middle latency vestibular evoked responses in human subjects. The head was held rigidly in a special, patented head holder, constructed individually for each subject, which gripped the teeth of the upper jaw. The stimulus consisted of 2/sec steps of angular acceleration impulses produced by a special motor with intensities of about 10,000 degrees/sec 2 and with a rise time of 1-2 msec. The electrical activity was recorded as the potential difference between special forehead and mastoid electrodes having a large, secure contact area with the skin. The activity was digitally filtered and averaged in 2 separate channels by means of a Microshev 2000 evoked response system. The short latency responses, with peaks at about 3.5 msec (forehead positive), 6.0 msec (forehead negative) and 8.4 msec (forehead positive; bandpass: 200-2000 Hz; average of 1024 trials), had amplitudes of about 0.5 microV. The middle latency responses had peaks at about 8.8 msec (forehead positive), 18.8 msec (forehead negative) and 26.8 msec (forehead positive; 30-300 Hz; N = 128 trials), with larger amplitudes (about 15 microV). These responses were consistently recorded in the same subject at different times and were similar in different normal subjects. Strenuous control experiments were conducted in order to ensure that these responses are not artefacts due to the movement of conducting media (head, electrodes and leads) in the electromagnetic field of the motor and are elicited by activation of normal labyrinths.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
1000.
Because of the trend toward a marked decrease in length of psychiatric hospitalization, clinicians need to improve the organization of the therapeutic milieu so that behavioral changes can be effected more rapidly. A university general psychiatric unit has adapted a problem-solving model that integrates groups and activities so that each one focuses on complementary behavioral objectives for each patient with the aim of effecting more rapid behavior change. The stages of the model are incorporated in a weekly sequence that begins with a goal-setting group. In a series of subsequent groups, each patient tries to develop and implement a solution to the problem identified that week. At the end of each week, patients participate in a goal review group, with feedback from staff and peers and self-reinforcement. The model can be used with a diverse patient population without interfering with each patient's individual psychotherapy or pharmacotherapy.  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