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   1886篇
  免费   91篇
  国内免费   11篇
耳鼻咽喉   6篇
儿科学   42篇
妇产科学   48篇
基础医学   263篇
口腔科学   104篇
临床医学   85篇
内科学   407篇
皮肤病学   31篇
神经病学   251篇
特种医学   52篇
外科学   317篇
综合类   3篇
一般理论   1篇
预防医学   84篇
眼科学   47篇
药学   150篇
中国医学   11篇
肿瘤学   86篇
  2023年   12篇
  2022年   22篇
  2021年   65篇
  2020年   41篇
  2019年   50篇
  2018年   47篇
  2017年   28篇
  2016年   25篇
  2015年   33篇
  2014年   57篇
  2013年   76篇
  2012年   115篇
  2011年   131篇
  2010年   64篇
  2009年   65篇
  2008年   124篇
  2007年   94篇
  2006年   131篇
  2005年   116篇
  2004年   124篇
  2003年   102篇
  2002年   93篇
  2001年   30篇
  2000年   40篇
  1999年   41篇
  1998年   13篇
  1997年   22篇
  1996年   9篇
  1995年   11篇
  1994年   9篇
  1993年   8篇
  1992年   22篇
  1991年   19篇
  1990年   15篇
  1989年   12篇
  1988年   11篇
  1987年   9篇
  1986年   9篇
  1985年   11篇
  1984年   6篇
  1983年   9篇
  1982年   4篇
  1981年   6篇
  1980年   5篇
  1979年   11篇
  1978年   7篇
  1977年   6篇
  1976年   6篇
  1975年   4篇
  1973年   4篇
排序方式: 共有1988条查询结果,搜索用时 15 毫秒
91.
92.
BACKGROUND: Recent reports have suggested that bipolar disorder beginning in late life is strongly associated with organic brain disease whereas early-onset cases are more likely to be associated with a family history of mood disorder. It is not yet clear whether late-onset bipolar disorder is therefore a "phenocopy" of the classic early-onset disorder, sharing symptoms but having a different etiology, or whether people with early- and late-onset bipolar disorder have a common underlying vulnerability that interacts with age-specific triggering factors. AIM: The present study examines the administrative records of patients treated for bipolar disorder, to establish whether differences between early- and late-onset cases might be consistent with their having distinct etiological processes. METHODS: We used a file containing administrative data for all patients with a diagnosis of bipolar disorder who were in contact with the health services of Western Australia between 1980 and 1998. For each contact with psychiatric services, the file provided the patient's age, gender, marital status, educational achievement, employment, ethnic origin, postcode of residence, primary and secondary diagnoses, and the duration of the (administrative) episode. Subjects were designated "late-onset" when their first contact with psychiatric services occurred at or after 65 years of age. RESULTS: Between 1980 and 1998 there were 33,004 service contacts involving 6,182 individuals whose primary or secondary clinical diagnosis was bipolar disorder. This indicates that the prevalence of bipolar disorder in Western Australia is approximately 0.4%. Most patients had an onset of illness between 15 and 45 years of age, but 492 patients (8%) were aged 65 years or over at the time of first contact with mental health services. We observed that the relative frequency of late-onset bipolar disorder increased between 1980 and 1998 (1% to 11%). There was an excess of women in our cohort (3:2), but no difference in the age of onset between males and females. Early onset was associated with a subsequently lower socioeconomic status, aboriginal ethnicity, and a higher frequency of mixed affective episodes, other mood disorders, schizophrenia, and schizoaffective disorder. Patients with late-onset bipolar disorder were more likely to have a diagnosis of organic mental disorder recorded (2.8% vs. 1.2%). There was no evidence of a bimodal pattern of age-specific incidence. CONCLUSION: The observed differences between early- and late-onset bipolar disorders are small and most likely attributable to differences in the duration of illness. Only a small proportion of patients with bipolar disorder were ever diagnosed with an organic mental disorder, which suggests that the reported association between late onset of illness and organic factors may be of limited clinical relevance.  相似文献   
93.
Studies comparing 'subjective experiences' in schizophrenic and affective disorders have reached inconclusive results. We investigated the pattern of 'subjective perceived cognitive disturbances' in a group of 55 schizophrenic patients and 39 bipolar patients hospitalized for an index psychotic episode. The assessment of the subjective experiences was made using the Frankfurter Beschwerde-Fragebogen (FBF). Comparing the two groups on the four FBF factors, schizophrenic patients showed significantly higher scores in the areas of 'central cognitive disturbances', 'perception and motility' other than a significantly higher FBF total score. Our results suggest that cognitive, perception and motility disturbances are the most characteristic subjective experiences of schizophrenic patients in comparison with bipolar patients. This finding need to be further explored in light of the issue of cognitive dysfunction in schizophrenia.  相似文献   
94.
PURPOSE: To investigate the role of technetium-99m (99mTc) tetrofosmin single-photon emission Computed Tomography (SPECT) associated with nitrate administration in the detection of hypoperfused but still viable myocardium in patients with chronic coronary artery disease and left ventricular (LV) dysfunction. MATERIAL AND METHODS: Twenty-two patients (mean age 54 +/- 11 years) with coronary artery disease, previous myocardial infarction and LV dysfunction (LV ejection fraction 38 +/- 13%) were examined. On different days all patients underwent 99mTc tetrofosmin (740 MBq) SPECT under control conditions at rest and after sublingual nitroglycerin administration (10 mg). Regional tetrofosmin activity was quantitatively measured in 22 myocardial segments per patient. In each segment, tracer uptake was expressed as a percentage of the region with the peak activity. RESULTS: Under control conditions, 267 myocardial segments (55%) showed normal tetrofosmin uptake (> 70% of peak activity), 107 segments (22%) showed a moderate reduction (51-70%) and 110 segments (23%) a severe reduction (< or = 50%) in tracer uptake. Among the 110 segments with a severe reduction in tetrofosmin uptake, 20 (18%) showed increased tracer uptake > or = 10% of after nitrate administration (from 44 +/- 5% to 58 +/- 3%, p < 0.0001). The remaining 90 (82%) segments with a severe reduction in tetrofosmin uptake did not show any change after nitroglycerin administration (from 38 +/- 9% to 39 +/- 8%, p = ns). CONCLUSIONS: In patients with chronic coronary artery disease and LV dysfunction, tetrofosmin cardiac SPECT associated with sublingual nitrate administration allows the detection of severely hypoperfused but still viable myocardium.  相似文献   
95.
We review the etiology and age incidence of precocious puberty in 438 girls examined between 1988-1998; 428 (97.7%) had central precocious puberty (CPP), the remaining 10 (2.3%) gonadotropin-independent precocious puberty (GIPP) of ovarian origin. The majority of CPP girls (59.6%) were aged between 7-7.9 yr, 22.4% were 6 year olds, and only 18% were under 6 years old. Cranial CT and/or MRI performed in 304/428 girls, showed neurogenic abnormalities in 56/304 (18.4%) CPP girls; 30 (9.9%) were due to previously diagnosed intracranial abnormalities and the remaining 26 (8.5%) were detected at the diagnosis of CPP. The frequency of neurogenic CPP tended to be higher in girls under 4 years of age while the frequency of idiopathic CPP tended to be higher in girls aged between 7-7.9 years, but no statistically significant differences were found. Interestingly, some CNS anomalies either of tumoral or congenital origin were detected at presentation in 7% of the girls aged over 7 years. Other related or coincidental clinical anomalies, mainly due to genetic diseases, were observed in 22/304 (7.2%) patients. History of precocious maternal menarche was found in 12/304 (4%) girls. In conclusion, idiopathic CPP was observed in 74% of the girls in this study. Neurogenic anomalies or other coincidental or related clinical findings were observed in the remaining 26%. The increased frequency of idiopathic CPP in girls aged over 7 years may suggest an early, but otherwise normal onset of puberty in many of these girls as a consequence of the trend towards earlier maturation. Nonetheless, the finding of CNS anomalies also in the older patients, raises the question of whether these patients should undergo a complete diagnostic work-up.  相似文献   
96.

Objective

To evaluate if the use of lidocaine gel applied to the cervix prior to manual vacuum aspiration (MVA) in addition to paracervical blockade is useful in reducing the level of pain associated with the procedure.

Methods

A total of 88 patients were randomized to receive either 5?mL of lidocaine gel or a placebo applied topically to the cervix 5 minutes prior to paracervical blockade. Both groups received the same drugs for pain control (tramadol hydrochloride, diazepam, and sodium diclofenac). A visual analogue scale (VAS) was used for evaluation of pain intensity at two times: 2 minutes before the blockade (directly after tenaculum clamping of the anterior aspect of the cervix) and after MVA of the uterine cavity.

Results

There was a statistically significant difference in pain intensity between the arms of the study. At the first evaluation time (cervical clamping), VAS pain score for the placebo group (control) was 3.6 (2.1) and that for the lidocaine gel group (case) was 1.2 (1.4) (P?<?0.01). At the second evaluation time (after manual vacuum aspiration), VAS pain score perceived by the control group was 5.3 (2.5) and that for the case group was 3.1 (1.9) (P?<?0.01). The use of lidocaine gel was not associated with any adverse effects of interest.

Conclusion

The use of a topical lidocaine gel plus paracervical blockade was effective in reducing the intensity of pain associated with MVA when compared to paracervical blockade alone.  相似文献   
97.
In this work we analyzed the immunoreactive-methionine-enkephalin (IR-Met-enkephalin) levels in several brain regions of rats sacrificed during the tonic extension, induced by acute treatment with pentylenetetrazol (PTZ). The results show an increase of IR-Met-enkephalin content in striatum but not in amygdala, hypothalamus, septum, hippocampus and cortex. To characterize whether this elevation of enkephalin levels in striatum corresponded to the releasable pool, we studied the intro efflux of this peptide in striatal slices of rats sacrificed during the seizures, in acute PTZ and in PTZ-kindled rats (kindling group I). In addition, PTZ-kindled rats were analyzed 24 h after the last stimulus (kindling group II). The striatal slices of acute group and kindling group I displayed a significant increase in the evoked release of IR-Met-enkephalin. However, no significant changes occurred from striatal slices of kindling group II animals. In vitro superfusion of GABA (100 μM) produced a 63% decrease in IR-Met-enkephalin released from striatal slices in both saline and acute PTZ-treated rats. Several studies suggest that opioid peptides may be released in the ictal phase of seizure in order to mediate some transient postictal behavior. Our results suggest that of several brain regions tested, only the striatal IR-Met-enkephalin may be released during the ictus to mediate postical behavior in the acute PTZ treated and in PTZ-kindled rats. This effect may be regulated by the GABA system.  相似文献   
98.
A 21-year-old woman had myasthenic symptoms since birth that responded poorly to anticholinesterase therapy. Tests for acetylcholine receptor (AChR) antibodies were negative. An intercostal muscle specimen was obtained to investigate the character of the neuromuscular transmission defect. There were no immune deposits at the endplates. The quantal content of the endplate potential was normal. Miniature endplate potentials and currents were very small, but the number of AChR per endplate was normal. On electron microscopy, the synaptic vesicles were of normal size, the junctional folds were intact, and the density and distribution of AChR on the folds was normal. The kinetic properties of AChR were studied by analysis of acetylcholine (ACh)-induced current noise. The mean single channel conductance was normal. The noise power spectrum was abnormal, containing two components of different time course. This could result from an abnormal interaction of ACh with AChR, or from two populations of AChR at the endplate. The second possibility is unlikely because if two populations of AChR were present at the endplate, then both would have to have low conductance to explain the small miniature endplate current, but the average conductance of the channels that did open was normal. © 1993 John Wiley & Sons, Inc.  相似文献   
99.
Six children, originally regarded as being affected by prepubertal idiopathic growth failure, were found to have pituitary microadenomas. In all six patients, the growth failure (? 2 cm/yr) was the primary clinical sign, and was accompanied by a growth hormone deficiency that was discovered during the laboratory evaluation. Prominent alteration of the sella turcica was not demonstrated in the skull x-ray examinations of any of the children, even when the x-ray examinations were supplemented by hypocycloidal tomography. CT scanning proved to be a very useful integrating diagnostic procedure, revealing the adenoma to be a nodular area of increased density within the sella turcica. In all of the children, resumption of normal growth was obtained following the surgical removal of the tumor through a transsphenoidal approach.  相似文献   
100.
We present a case of cutaneous leiomyomas (CL) arising in a pleomorphic adenoma (PA) of the parotid gland. PA and CL are benign tumors arising from the parotid gland and the erector pilli muscle, respectively. They both have a benign clinical course and in most cases leiomyomas are multiple in nature. PAs of the parotid are the most frequent benign tumors of the major salivary glands. To our knowledge this is the first case of PA with CL.  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