全文获取类型
收费全文 | 11860篇 |
免费 | 813篇 |
国内免费 | 183篇 |
专业分类
耳鼻咽喉 | 115篇 |
儿科学 | 259篇 |
妇产科学 | 426篇 |
基础医学 | 1554篇 |
口腔科学 | 401篇 |
临床医学 | 1132篇 |
内科学 | 2624篇 |
皮肤病学 | 211篇 |
神经病学 | 935篇 |
特种医学 | 427篇 |
外国民族医学 | 3篇 |
外科学 | 1900篇 |
综合类 | 260篇 |
一般理论 | 4篇 |
预防医学 | 615篇 |
眼科学 | 117篇 |
药学 | 668篇 |
1篇 | |
中国医学 | 47篇 |
肿瘤学 | 1157篇 |
出版年
2023年 | 73篇 |
2022年 | 124篇 |
2021年 | 346篇 |
2020年 | 187篇 |
2019年 | 257篇 |
2018年 | 319篇 |
2017年 | 221篇 |
2016年 | 267篇 |
2015年 | 304篇 |
2014年 | 390篇 |
2013年 | 497篇 |
2012年 | 818篇 |
2011年 | 801篇 |
2010年 | 453篇 |
2009年 | 390篇 |
2008年 | 657篇 |
2007年 | 774篇 |
2006年 | 609篇 |
2005年 | 628篇 |
2004年 | 597篇 |
2003年 | 513篇 |
2002年 | 513篇 |
2001年 | 349篇 |
2000年 | 349篇 |
1999年 | 345篇 |
1998年 | 132篇 |
1997年 | 123篇 |
1996年 | 91篇 |
1995年 | 84篇 |
1994年 | 99篇 |
1993年 | 73篇 |
1992年 | 173篇 |
1991年 | 161篇 |
1990年 | 132篇 |
1989年 | 151篇 |
1988年 | 84篇 |
1987年 | 121篇 |
1986年 | 84篇 |
1985年 | 56篇 |
1984年 | 67篇 |
1983年 | 43篇 |
1982年 | 26篇 |
1981年 | 30篇 |
1980年 | 27篇 |
1979年 | 46篇 |
1978年 | 23篇 |
1976年 | 32篇 |
1975年 | 22篇 |
1974年 | 29篇 |
1972年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
de Pontual L Népote V Attié-Bitach T Al Halabiah H Trang H Elghouzzi V Levacher B Benihoud K Augé J Faure C Laudier B Vekemans M Munnich A Perricaudet M Guillemot F Gaultier C Lyonnet S Simonneau M Amiel J 《Human molecular genetics》2003,12(23):3173-3180
Congenital central hypoventilation syndrome (CCHS, Ondine's curse) is a rare disorder of the chemical control of breathing. It is frequently associated with a broad spectrum of dysautonomic symptoms, suggesting the involvement of genes widely expressed in the autonomic nervous system. In particular, the HASH-1-PHOX2A-PHOX2B developmental cascade was proposed as a candidate pathway because it controls the development of neurons with a definitive or transient noradrenergic phenotype, upstream from the RET receptor tyrosine kinase and tyrosine hydroxylase. We recently showed that PHOX2B is the major CCHS locus, whose mutation accounts for 60% of cases. We also studied the proneural HASH-1 gene and identified a heterozygous nucleotide substitution in three CCHS patients. To analyze the functional consequences of HASH-1 mutations, we developed an in vitro model of noradrenergic differentiation in neuronal progenitors derived from the mouse vagal neural crest, reproducing in vitro the HASH-PHOX-RET pathway. All HASH-1 mutant alleles impaired noradrenergic neuronal development, when overexpressed from adenoviral constructs. Thus, HASH-1 mutations may contribute to the CCHS phenotype in rare cases, consistent with the view that the abnormal chemical control of breathing observed in CCHS patients is due to the impairment of noradrenergic neurons during early steps of brainstem development. 相似文献
72.
Simbirtsev SA Loĭt AA Lebedev AK Kagan II Zheleznov LM 《Morfologii?a (Saint Petersburg, Russia)》1999,116(5):72-74
Method of creation computer models of upper floor of abdomen organs: liver, gallbladder, duodenum, pancreas, stomach, blood vessels with using computer system "DUCT" was described. Details of modelled structures of the cylindric and complicated forms were noted. 相似文献
73.
Bilateral simultaneous tubal sextuplets: pregnancy after in-vitro fertilization--embryo transfer following salpingectomy 总被引:2,自引:1,他引:2
The presence of a damaged tube has been suggested in recent studies to have
a negative effect on in-vitro fertilization (IVF) outcome. Performing
bilateral salpingectomy prior to IVF to maximize pregnancy rates may also
result in unnecessary surgery. This case is also an example of the
occurrence of interstitial pregnancy after salpingectomy. This unusual type
of ectopic pregnancy must be kept in mind when evaluating a patient
suspected of a possible early abnormal gestation after assisted
reproductive technolologies.
相似文献
74.
S. K. F. Lo K. W. Y. Ip P. K. S. Chan J. M. Nicholls R. B. Heath S. Y. W. Shiu 《Archives of virology》1993,129(1-4):295-299
Summary Human cytomegalovirus (HCMV) infection is an important cause of neonatal death. Using primers derived from sequences within the morphological transforming region II (mtrII), HCMV DNA was amplified by polymerase chain reaction (PCR) from fixed tissues of infants who had died of congenital HCMV infection. In one neonate, HCMV DNA with reduction in the expected size was detected in the liver, spleen, kidney, adrenal, und thyroid tissues by gel electrophoresis. Nucleotide sequencing of the PCR product revealed a 65bp frame-shift deletion within the 79 amino acid open reading frame (ORF) of themtrII. Based upon this observation, it is likely that viral genomic rearrangement involving themtrII may occur in some cases of congenital HCMV infection. 相似文献
75.
Pulmonary pathological features in coronavirus associated severe acute respiratory syndrome (SARS) 总被引:5,自引:0,他引:5
Tse GM To KF Chan PK Lo AW Ng KC Wu A Lee N Wong HC Mak SM Chan KF Hui DS Sung JJ Ng HK 《Journal of clinical pathology》2004,57(3):260-265
BACKGROUND: Severe acute respiratory syndrome (SARS) became a worldwide outbreak with a mortality of 9.2%. This new human emergent infectious disease is dominated by severe lower respiratory illness and is aetiologically linked to a new coronavirus (SARS-CoV). METHODS: Pulmonary pathology and clinical correlates were investigated in seven patients who died of SARS in whom there was a strong epidemiological link. Investigations include a review of clinical features, morphological assessment, histochemical and immunohistochemical stainings, ultrastructural study, and virological investigations in postmortem tissue. RESULTS: Positive viral culture for coronavirus was detected in most premortem nasopharyngeal aspirate specimens (five of six) and postmortem lung tissues (two of seven). Viral particles, consistent with coronavirus, could be detected in lung pneumocytes in most of the patients. These features suggested that pneumocytes are probably the primary target of infection. The pathological features were dominated by diffuse alveolar damage, with the presence of multinucleated pneumocytes. Fibrogranulation tissue proliferation in small airways and airspaces (bronchiolitis obliterans organising pneumonia-like lesions) in subpleural locations was also seen in some patients. CONCLUSIONS: Viable SARS-CoV could be isolated from postmortem tissues. Postmortem examination allows tissue to be sampled for virological investigations and ultrastructural examination, and when coupled with the appropriate lung morphological changes, is valuable to confirm the diagnosis of SARS-CoV, particularly in clinically unapparent or suspicious but unconfirmed cases. 相似文献
76.
Torti C Quiros-Roldan E Monno L Patroni A Saracino A Angarano G Tinelli C Lo Caputo S Tirelli V Mazzotta F Carosi G;MASTER Cohort GenPheRex Study Group;MASTER Cohort PhenGen Study Group 《Journal of medical virology》2004,74(1):29-33
This study aimed at identifying HIV-1 protease amino acid changes associated with protease inhibitor (PI) exposure and susceptibility. New amino acid substitutions were correlated with the number of experienced PIs, reaching statistical significance only for those at positions 3, 44, and 74. The correspondence multivariate model demonstrated that > or =3 experienced PIs and substitutions or mutations at positions 3, 46, 54, 73, 74, and 84 were correlated with PI cross-resistance, including resistance for lopinavir and amprenavir in this cohort of patients who were naive for these drugs. 相似文献
77.
Fishbein DA Lo Y Reinus JF Gourevitch MN Klein RS 《Journal of acquired immune deficiency syndromes (1999)》2004,37(3):1367-1375
The objective of this study was to determine outcomes of referring drug users (DUs) with chronic hepatitis C for clinical evaluation and care. Two hundred twenty-eight persons with detectable hepatitis C virus RNA were given expedited referrals for evaluation and possible treatment of hepatitis C from a prospective study cohort of current and former opiate-addicted DUs. Four outcomes were analyzed: accepted referral, arrived for clinical evaluation, had liver biopsy, and received treatment. One hundred twenty-seven participants (56%) accepted referral, of whom 54 (43%) arrived for evaluation. Of these participants, 12 (22%) had liver biopsy, and 4 (7%) were treated. Multivariate logistic regression revealed that HIV-infected DUs were significantly less likely to accept referral (adjusted odds ratio [O(Radj)], 0.51; 95% confidence interval [CI], 0.30-0.88), and older participants were more likely to keep an appointment (O(Radj), 1.06/y; 95% CI, 1.00-1.12). Of HIV-seropositive participants, those with a history of injection were more likely to accept referral (O(Radj), 3.60; 95% CI, 1.08-11.96), and those with higher HIV load (O(Radj), 0.50/log10; 95% CI, 0.26-0.94) and Hispanic ethnicity (O(Radj), 0.26; 95% CI, 0.07-0.89) were less likely to keep an appointment. Despite expedited referrals for hepatitis C care, only a few participants received an evaluation, and even far fewer were treated. Because increasingly effective treatment is available, better methods are urgently needed to improve evaluation and treatment of HCV-infected DUs, including those coinfected with HIV. 相似文献
78.
79.
80.
The effects of a 3-day tail suspension on central and peripheral sympathetic activity were studied in rats by determining the in vivo noradrenaline (NA) turnover in the brain cell groups involved in central blood pressure control (A1, A2, A5 and A6) and in two peripheral organs, heart and kidneys. In addition, cardiovascular parameters and their variabilities were investigated by recording blood pressure (BP) and heart rate (HR) before and after suspension. These measurements were processed by spectrum analysis to assess the influence of tail suspension on autonomic balance. The NA turnover in the suspended rats was markedly reduced in A2 (–49%, P<0.01) and A5 (–38%, P<0.01) nuclei but unchanged in A1 and A6 cell groups compared with the control rats. Peripheral NA turnover was decreased in cardiac atria (–44%, P<0.001) and ventricles (–27%, P<0.01) while it was unchanged in kidneys after suspension. The BP, HR and their variabilities were similar in both groups of animals and showed no changes after suspension compared with baseline values. Spectrum analysis of BP and HR in our conscious suspended rats revealed no changes in power spectrum density or in peak frequencies. The discrepancy between the decrease in central sympathetic activity and the absence of changes in cardiovascular parameters after tail suspension raises the question of the validity of the tail suspended rat model when studying the cardiovascular deconditioning observed in humans after an exposure to actual or simulated weightlessness. 相似文献