全文获取类型
收费全文 | 3775篇 |
免费 | 208篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 47篇 |
儿科学 | 175篇 |
妇产科学 | 116篇 |
基础医学 | 436篇 |
口腔科学 | 62篇 |
临床医学 | 232篇 |
内科学 | 856篇 |
皮肤病学 | 95篇 |
神经病学 | 289篇 |
特种医学 | 233篇 |
外科学 | 609篇 |
综合类 | 99篇 |
一般理论 | 1篇 |
预防医学 | 163篇 |
眼科学 | 137篇 |
药学 | 257篇 |
中国医学 | 11篇 |
肿瘤学 | 174篇 |
出版年
2023年 | 37篇 |
2022年 | 55篇 |
2021年 | 129篇 |
2020年 | 55篇 |
2019年 | 94篇 |
2018年 | 134篇 |
2017年 | 94篇 |
2016年 | 104篇 |
2015年 | 109篇 |
2014年 | 142篇 |
2013年 | 146篇 |
2012年 | 257篇 |
2011年 | 262篇 |
2010年 | 132篇 |
2009年 | 115篇 |
2008年 | 178篇 |
2007年 | 186篇 |
2006年 | 201篇 |
2005年 | 160篇 |
2004年 | 166篇 |
2003年 | 135篇 |
2002年 | 119篇 |
2001年 | 115篇 |
2000年 | 96篇 |
1999年 | 70篇 |
1998年 | 33篇 |
1997年 | 18篇 |
1996年 | 16篇 |
1995年 | 13篇 |
1992年 | 47篇 |
1991年 | 41篇 |
1990年 | 42篇 |
1989年 | 39篇 |
1988年 | 28篇 |
1987年 | 35篇 |
1986年 | 38篇 |
1985年 | 27篇 |
1984年 | 33篇 |
1983年 | 21篇 |
1982年 | 21篇 |
1979年 | 19篇 |
1978年 | 18篇 |
1977年 | 15篇 |
1976年 | 13篇 |
1975年 | 16篇 |
1974年 | 13篇 |
1973年 | 15篇 |
1972年 | 14篇 |
1968年 | 13篇 |
1967年 | 13篇 |
排序方式: 共有3992条查询结果,搜索用时 15 毫秒
71.
72.
Hitesh Chawla Rohtas K Yadav Mahavir S Griwan Ranjana Malhotra Pramod K Paliwal 《The Australasian medical journal》2015,8(7):235-238
Background
Emergency departments rely on CT scans to manage trauma victims, especially for head injuries. Although the detection of an undisplaced fracture on a CT scan of the head without significant intracranial findings may be insignificant for a clinician, such cases are of paramount importance for medico-legal purposes because they help ascertain the nature, manner, and cause of the head injury.Aims
The study was conducted with the objective of knowing the sensitivity and specificity of ante-mortem CT scan findings indicating the presence or absence of skull fractures.Methods
Findings were confirmed during post-mortem examination of the subjects who had died during management but who had not had any surgical intervention. A comparative study of ante-mortem CT scan and autopsy findings with respect to fracture in traumatic head injuries was undertaken on 60 deceased individuals brought in for medico-legal post-mortem examination over a period of two years.Results
Considering the autopsy findings as the gold standard, we have concluded that 14.6 per cent of the fractures were missed on CT scan findings compared to fractures found during autopsy. The sensitivity of CT scan for skull fractures was found to be 85.4 per cent and specificity was 100 per cent. Kappa was 0.787, which shows good agreement with p<0.001, which was highly significant.Conclusion
In developing countries, images are interpreted in the axial plane only on a CT scan of the head, which may be due to a lack of financial and human resources. For better delineation of fractures, the use of techniques like multi-detector CT with sagittal and coronal reformations should be considered in the routine interpretation of a CT scan of the head. 相似文献73.
Ritika Sharma Manu Jamwal Hari Kishan Senee Varun Uppal Jasbir Kaur Hira Parveen Bose Narender Kumar Deepak Bansal Amita Trehan Pankaj Malhotra Jasmina Ahluwalia Reena Das 《Indian journal of hematology & blood transfusion》2021,37(3):414
Glanzmann thrombasthenia (GT) is an autosomal recessive platelet function disorder characterized by mucocutaneous bleeding as the most common clinical phenotype. Patients with GT have normal platelet counts, platelet morphology but reduced platelet aggregation in response to various agonists. Homozygosity or compound heterozygosity for variants in the ITGA2B/ITGB3 genes is the genetic basis for GT. Establishing a molecular diagnosis is definitive and is important for predictive testing. Using multi-gene panels is an accurate, faster, and cost-effective mode as compared to Sanger sequencing in large genes. We used a targeted resequencing based approach to identify pathogenic variants in eight cases in seven families. These variants were validated using Sanger sequencing in patients as well as family members and were predicted probably pathogenic using in-silico prediction tools. The variants include three missense (3/7 = 43%) (ITGA2B:c.1028 T > C, ITGA2B:c.1186G > A, ITGB3:c.1388G > C), two deletions (ITGA2B:c.559delG, ITGA2B:c.3092delT), one duplication (ITGA2B:c.1424_1427dupAGGT) and nonsense variant (ITGA2B:c.2578C > T, p.Gln860Ter). Except for one case which was compound heterozygous, the rest of the cases were homozygous. We found two novel variants that are reported for the first time in GT. The targeted resequencing based approach revealed varied genetic variants in North Indian patients, including two novels ones. The high yield of our panel indicates its suitability for usage in larger cohorts for the genetic diagnosis of GT patients. This approach is cost-effective and less cumbersome as compared to Sanger sequencing for these large size genes with multiple exons. The information so obtained is helpful in prenatal testing, carrier analysis, and genetic counseling. 相似文献
74.
Chatterjee T Dixit A Mohapatra M Tyagi S Gupta PK Mishra P Bhattacharya M Karan AS Pati HP Saxena R Choudhry VP 《European journal of haematology》2004,73(2):93-97
Myelodysplastic syndromes (MDS) are clonal haematopoietic stem cell disorders characterised by ineffective and dyspoietic haematopoiesis. The natural history of these disorders is variable and ranges from a chronic to a rapid course towards leukaemic progression. Certain shortcomings have been encountered in the French-American-British (FAB) classification over the years, and therefore there is a need for an alternative method of classification. In 1999, the WHO published a revised classification of MDS. In the present study, we have analysed the clinical, haematological and histomorphological features in 96 cases of primary MDS seen in the department of haematology at the All India Institute of Medical Sciences (AIIMS) over a 6-yr period (1996-2001). Both FAB and WHO classifications have been incorporated and the Bournemouth scoring system applied in each case at presentation. The Bournemouth scoring system, in the absence of a cytogenetic study, offers a good prognostication and long-term survival estimate. 相似文献
75.
G K Rastogi M S Malhotra M C Srivastava R C Sawhney G L Dua K Sridharan R S Hoon I Singh 《The Journal of clinical endocrinology and metabolism》1977,44(3):447-452
The alterations in serum levels of T3, T4, TSH and TBG, TSH response to 100 mug iv TRH, and urinary excretion of T3 and T4 were studied in 8 healthy men at sea level (SL), on days 1, 2, 4, 8 and 16 after arrival by air at high altitude (3,700 m, HA), and during days 5 to 7 after their return to SL. No significant alterations in serum levels of TSH and TBG or TSH response to TRH were observed during exposure to HA or on return to SL. There was, however, an acute elevation in both serum total T3 and T4. Serum total T3 from a mean basal+/-SE value of 128+/-13 ng/dl increased to 320+/-18 on day 1 and remained significantly elevated at 225+/-48 up to day 8 after arrival at high altitude. Similarly serum total T4 increased from basal level of 9+/-0.92 mug/dl to 15.2+/-1.2 and remained elevated till day 16 and it was 11+/-1.19 mug/dl during days 5 to 7 after return to SL. The urinary excretion of both T3 and T4 was decreased. These changes perhaps were the result of complex physiologic adjustments on acute exposure to high altitude, like shrinkage of the T3 and T4 distribution pools, altered binding capacities of thyroid hormones binding proteins, and a reduction in clearance of thyroid hormones from the plasma compartment; and were probably not suggestive of an enhanced thyroid activity. Their actual significance in high altitude adaptation in man is not clearly understood. 相似文献
76.
GOALS: To report the use of pH-impedance testing in evaluating patients with suspected gastroesophageal reflux disease (GERD) with atypical symptoms. BACKGROUND: Although the role of acid reflux in causing atypical GERD symptoms is generally accepted, the role, if any, of nonacid reflux is controversial, largely because until recently it has not been possible to detect nonacid reflux. The advent of intraluminal combined pH impedance testing (MII-pH), to detect nonacid reflux has heightened interest in its possible contribution to atypical symptoms. STUDY: Fifty consecutive patients referred for MII-pH testing to evaluate the cause of atypical symptoms presumed due to GERD were evaluated. The symptoms were either refractory to acid inhibition therapy or so atypical that further work up was desired by the referring physician. Patients underwent MII-pH testing to determine whether reflux was present, and, if so, if it was due to acid, nonacid, or gas. RESULTS: Only 16%, 22%, and 2% patients were found to have symptoms due to acid reflux, nonacid reflux, or both, respectively. Ten percent of these patients had gas reflux. MII-pH testing was useful in redirecting the management of patients who did not have reflux as the cause of their symptoms. CONCLUSIONS: MII-pH testing is useful in determining whether gastroesophageal reflux is present in patients with atypical symptoms that have not responded to proton pump inhibitor therapy. It also distinguishes between reflux due to acid, nonacid, and gas, with consequences for management. 相似文献
77.
Yasar Kucukardali Oral Oncul Saban Cavuslu Mehmet Danaci Semra Calangu Hakan Erdem Ayse Willke Topcu Zuhal Adibelli Murat Akova Emel Azak Karaali Ahmet Melih Ozel Zahit Bolaman Bulent Caka Birsen Cetin Erkan Coban Oguz Karabay Cagla Karakoc Mehmet Akif Karan Selda Korkmaz Gulsen Ozkaya Sahin Alaaddin Pahsa Fatma Sirmatel Emrullah Solmazgul Namik Ozmen Ilyas Tokatli Cengiz Uzun Gulsen Yakupoglu Bulent Ahmet Besirbellioglu Hanefi Cem Gul 《International journal of infectious diseases》2008,12(1):71-79
OBJECTIVE: The purpose of this trial was to determine the spectrum of diseases with fever of unknown origin (FUO) in Turkey. METHODS: A prospective multicenter study of 154 patients with FUO in twelve Turkish tertiary-care hospitals was conducted. RESULTS: The mean age of the patients was 42+/-17 years (range 17-75). Fifty-three (34.4%) had infectious diseases (ID), 47 (30.5%) had non-infectious inflammatory diseases (NIID), 22 (14.3%) had malignant diseases (MD), and eight (5.2%) had miscellaneous diseases (Mi). In 24 (15.6%) of the cases, the reason for high fever could not be determined despite intensive efforts. The most common ID etiologies were tuberculosis (13.6%) and cytomegalovirus (CMV) infection (3.2%). Adult Still's disease was the most common NIID (13.6%) and hematological malignancy was the most common MD (7.8%). In patients with NIID, the mean duration of reaching a definite diagnosis (37+/-23 days) was significantly longer compared to the patients with ID (25+/-12 days) (p=0.007). In patients with MD, the mean duration of fever (51+/-35 days) was longer compared to patients with ID (37+/-38 days) (p=0.052). CONCLUSIONS: Although infection remains the most common cause of FUO, with the highest percentage for tuberculosis, non-infectious etiologies seem to have increased when compared with previous studies. 相似文献
78.
Malhotra R Holman M Ito T 《Proceedings of the National Academy of Sciences of the United States of America》2001,98(22):12342-12343
Over the last two decades, there has come about a recognition that chaotic dynamics is pervasive in the solar system. We now understand that the orbits of small members of the solar system-asteroids, comets, and interplanetary dust-are chaotic and undergo large changes on geological time scales. Are the major planets' orbits also chaotic? The answer is not straightforward, and the subtleties have prompted new questions. 相似文献
79.
80.
Mitchell G. Spring Aaron Caccamise Elizabeth A. Panther Bethany M. Windsor Karan R. Soni Jayme R. McReynolds Daniel S. Wheeler John R. Mantsch Robert A. Wheeler 《The Journal of neuroscience》2021,41(11):2428
Chronic stress impairs the function of multiple brain regions and causes severe hedonic and motivational deficits. One brain region known to be susceptible to these effects is the PFC. Neurons in this region, specifically neuronal projections from the prelimbic region (PL) to the nucleus accumbens core (NAcC), have a significant role in promoting motivated approach. However, little is known about how activity in this pathway changes during associative learning to encode cues that promote approach. Less is known about how activity in this pathway may be altered by stress. In this study, an intersectional fiber photometry approach was used in male Sprague Dawley rats engaged in a Pavlovian autoshaping design to characterize the involvement of the PL-NAcC pathway in the typical acquisition of learned approach (directed at both the predictive cue and the goal), and its potential alteration by stress. Specifically, the hypothesis that neural activity in PL-NAcC would encode a Pavlovian approach cue and that prior exposure to chronic stress would disrupt both the nature of conditioned approach and the encoding of a cue that promotes approach was tested. Results of the study demonstrated that the rapid acquisition of conditioned approach was associated with cue-induced PL-NAcC activity. Prior stress both reduced cue-directed behavior and impaired the associated cortical activity. These findings demonstrate that prior stress diminishes the task-related activity of a brain pathway that regulates approach behavior. In addition, the results support the interpretation that stress disrupts reward processing by altering the incentive value of associated cues.SIGNIFICANCE STATEMENT Chronic stress causes hedonic and motivational deficits and disrupts the function of the PFC. A specific projection from the prelimbic region of the PFC to the nucleus accumbens core (PL-NAcC) promotes approach behavior and is a strong candidate for contributing to stress-induced disruptions in motivation. However, it is not known how activity in this pathway encodes cues that promote approach, and how this encoding may be altered by stress. Here we show that the rapid acquisition of conditioned approach is associated with cue-induced activity in the PL-NAcC pathway. Prior stress both reduces cue-directed behavior and impairs the associated cortical activity. These findings demonstrate that stress diminishes task-related activity in a brain pathway that regulates approach behavior. 相似文献