全文获取类型
收费全文 | 1501篇 |
免费 | 58篇 |
国内免费 | 81篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 83篇 |
妇产科学 | 17篇 |
基础医学 | 164篇 |
口腔科学 | 28篇 |
临床医学 | 260篇 |
内科学 | 362篇 |
皮肤病学 | 55篇 |
神经病学 | 34篇 |
特种医学 | 300篇 |
外科学 | 94篇 |
综合类 | 29篇 |
一般理论 | 3篇 |
预防医学 | 58篇 |
眼科学 | 7篇 |
药学 | 84篇 |
肿瘤学 | 61篇 |
出版年
2021年 | 8篇 |
2019年 | 12篇 |
2018年 | 7篇 |
2017年 | 12篇 |
2016年 | 11篇 |
2015年 | 25篇 |
2014年 | 15篇 |
2013年 | 31篇 |
2012年 | 12篇 |
2011年 | 16篇 |
2010年 | 53篇 |
2009年 | 58篇 |
2008年 | 21篇 |
2007年 | 59篇 |
2006年 | 23篇 |
2005年 | 27篇 |
2004年 | 9篇 |
2003年 | 14篇 |
2002年 | 18篇 |
2001年 | 18篇 |
2000年 | 20篇 |
1999年 | 30篇 |
1998年 | 105篇 |
1997年 | 99篇 |
1996年 | 117篇 |
1995年 | 94篇 |
1994年 | 92篇 |
1993年 | 82篇 |
1992年 | 27篇 |
1991年 | 35篇 |
1990年 | 29篇 |
1989年 | 38篇 |
1988年 | 37篇 |
1987年 | 33篇 |
1986年 | 36篇 |
1985年 | 34篇 |
1984年 | 15篇 |
1983年 | 25篇 |
1982年 | 25篇 |
1981年 | 23篇 |
1980年 | 21篇 |
1978年 | 14篇 |
1977年 | 16篇 |
1976年 | 13篇 |
1975年 | 13篇 |
1958年 | 20篇 |
1957年 | 9篇 |
1956年 | 17篇 |
1955年 | 24篇 |
1954年 | 11篇 |
排序方式: 共有1640条查询结果,搜索用时 15 毫秒
81.
Bals-Pratsch M; De Geyter C; Muller T; Frieling U; Lerchl A; Pirke KM; Hanker JP; Becker-Carus C; Nieschlag E 《Human reproduction (Oxford, England)》1997,12(5):896-904
Preliminary data have suggested that female infertility due to corpus
luteum insufficiency may be caused by subclinical hypothyroidism
[exaggerated thyroid-stimulating hormone (TSH) response to thyrotrophin-
releasing hormone (TRH) stimulation]. L-Thyroxine supplementation has been
recommended to achieve pregnancies in subclinical hypothyroid women. This
controlled study was carried out in order to investigate the biochemical
diagnosis of subclinical hypothyroidism as a possible infertility factor.
Five infertile patients (aged 25-36 years) with subclinical hypothyroidism
(n = 4, stimulated TSH >20 microU/ml) or primary hypothyroidism (n = 1)
and five healthy controls (aged 22-39 years) with normal thyroid function
(stimulated TSH <15 microU/ml), regular cycles and no history of
infertility were studied in the early follicular phase. In the pre-study
evaluation, eight of 23 volunteers (34.8%) had to be excluded because of
subclinical hypothyroidism with stimulated TSH values (TSHs) >15
microU/ml. Cycle function of patients and controls was compared by the
method of LH pulse pattern analysis. Therefore blood samples were drawn
every 10 min during a 24 h period. Sleep was recorded from midnight to 7
a.m. Repetition of the TRH tests at the end of the 24 h blood sampling
period confirmed the difference in stimulated TSH values of the two study
groups. Pulse analysis for luteinizing hormone (LH), TSH and prolactin
showed no differences between patients and controls for pulse frequency,
amplitude, height, length, area under curve (AUC) and the 24 h mean. Even
the hypothyroid patient had a normal LH pulse pattern. Additional
measurement of melatonin in pooled sera every 30 min gave the
well-documented diurnal profiles during day and night for both groups.
Patients had significantly higher melatonin values at seven time points
during the night. Peaks for LH, TSH, prolactin and cortisol were correlated
with the sleep stages wake, rapid eye movement, 1 + 2 and 3 + 4. We
concluded that corpus luteum insufficiency in female infertility cannot be
explained by subclinical hypothyroidism and thus should not be treated with
L-thyroxine for fertility reasons.
相似文献
82.
Assisted reproductive technology and complex chromosomal rearrangements: the limits of ICSI 总被引:4,自引:0,他引:4
Siffroi JP; Benzacken B; Straub B; Le Bourhis C; North MO; Curotti G; Bellec V; Alvarez S; Dadoune JP 《Molecular human reproduction》1997,3(10):847-851
Complex chromosomal rearrangements are very rare events in the human
population. According to our knowledge on the consequences of simple
reciprocal translocations for male fertility, translocations involving
three or more chromosomes are thought to lead to severe reproductive
impairments in terms of meiotic disturbance or chromosomal imbalance of
gametes. We report the case of a 48 year old man whose sperm count revealed
either oligozoospermia (<10(3) spermatozoa/ml) or azoospermia. He was
referred to the laboratory for in-vitro fertilization after
intracytoplasmic sperm injection. Cytogenetic investigations showed a
complex chromosomal rearrangement involving firstly a translocation between
the short arm of chromosome 7 and the long arm of chromosome 13 and
secondly a translocation between the short arm of the same chromosome 13
and the short arm of chromosome 9. Diagnosis was ascertained by
fluorescence in-situ hybridization and staining of the nucleolar organizer
regions. Theoretical study of the translocated chromosomes predicted a
'chain' configuration of the hexavalent at the pachytene stage of meiosis.
In all, 32 modes of segregation were considered and only one resulted
either in a normal or a balanced gamete karyotype. Genetic counselling and
choice of appropriate artificial reproduction technique are discussed.
相似文献
83.
The GAP-related domain of tuberin, the product of the TSC2 gene, is a target for missense mutations in tuberous sclerosis 总被引:5,自引:0,他引:5
Maheshwar MM; Cheadle JP; Jones AC; Myring J; Fryer AE; Harris PC; Sampson JR 《Human molecular genetics》1997,6(11):1991-1996
Tuberous sclerosis is an autosomal dominant trait in which the
dysregulation of cellular proliferation and differentiation results in the
development of hamartomatous growths in many organs. The TSC2 gene is one
of two genes determining tuberous sclerosis. Inactivating germline
mutations of TSC2 in patients with tuberous sclerosis and somatic loss of
heterozygosity at the TSC2 locus in the associated hamartomas indicate that
TSC2 functions as a tumour suppressor gene and that loss of function is
critical to expression of the tuberous sclerosis phenotype. The TSC2
product, tuberin, has a region of homology with the GTPase activating
protein rap1GAP and stimulates the GTPase activity of rap1a and rab5a in
vitro. Here we show that the region of homology between tuberin and human
rap1GAP and the murine GAP mSpa1 is more extensive than previously reported
and spans approximately 160 amino acid residues encoded within exons 34-38
of the TSC2 gene. Single strand conformation polymorphism analysis of these
exons in 173 unrelated patients with tuberous sclerosis and direct
sequencing of variant conformers together with study of additional family
members enabled characterisation of disease associated mutations in 14
cases. Missense mutations, which occurred in exons 36, 37 and 38 were
identified in eight cases, four of whom shared the same recurrent change
P1675L. Each of the five different missense mutations identified was shown
to occur de novo in at least one sporadic case of tuberous sclerosis. The
high proportion of missense mutations detected in the region of the TSC2
gene encoding the GAP-related domain supports its key role in the
regulation of cellular growth.
相似文献
84.
In our initial immunochemical study of the red blood cell (RBC) membrane proteins targeted in 20 cases of warm-antibody autoimmune hemolytic anemia (AHA), RBC eluates of 6 patients mediated immunoprecipitation (IP) of both band 3 and glycophorin A (GPA). This dual IP pattern had previously been observed with murine monoclonal antibodies (MoAbs) against the high frequency blood group antigen, Wrb (Wright), suggesting that the Wrb epitope may depend on a band 3-GPA interaction. Earlier, anti-Wrb had been identified serologically as a prominent non-Rh specificity of AHA autoantibodies. In the present study, 6 autoantibody eluates immunoprecipitating band 3 and GPA from common Wr(b+) RBCs were retested, in parallel with murine anti-Wrb MoAbs, against very rare Wr(a+b-)En(a+)RBCs. One patient's autoantibodies were unreactive with the Wr(b-) RBCs by either IP or indirect antiglobulin test (IAT) and were judged to have "pure" anti- Wrb specificity. Two other patients' autoantibodies displayed both IP and serologic evidence for anti-Wrb as a major component in combination with one or more additional specificities. However, among 3 other patients whose autoantibodies coprecipitated band 3 and GPA, there was no reduction in IP or IAT reactivity with Wr(b-) RBCs in 2 and only slight reduction in the third. We conclude (1) that human anti-Wrb autoantibodies, like their murine monoclonal counterparts, coprecipitate band 3 and GPA from human RBCs; but (2) that not all antibodies with this IP behavior have anti-Wrb serologic specificity, as defined by this donor's Wr(b-) RBCs. The possibility of an additional (non-Wrb) RBC epitope dependent on a band 3-GPA interaction is raised. 相似文献
85.
Lauener RP; Huttner S; Buisson M; Hossle JP; Albisetti M; Seigneurin JM; Seger RA; Nadal D 《Blood》1995,86(4):1400-1407
One mechanism proposed to play a role in T-cell depletion in human immunodeficiency virus (HIV) infection is apoptosis (activation-induced cell death). We assessed whether apoptosis is related to activation of T cells in vivo and its possible triggers. DNA was extracted from peripheral blood mononuclear cells (PBMC) taken from 16 vertically HIV- infected children and 9 HIV-negative children born to HIV-positive mothers (controls) and tested by agarose gel electrophoresis for the presence of DNA fragments specific for apoptosis. Signs of apoptosis were found on in vitro culture of PBMC from 12 of 16 HIV-infected children, but not in PBMC from the nine controls. Eleven of the 12 HIV- infected children with apoptosis showed an elevated (> 15%) proportion of CD3+/HLA-DR+ cells. This was due to an increased proportion of CD8+/HLA-DR+ cells, as shown in 7 of 7 further tested patients. In none of the probands an increased (> 5%) proportion of IL-2 receptor expressing CD3+ cells was found. T cells undergoing apoptosis were preferentially of the CD8+ phenotype. Expansion of circulating CD8+/interleukin-2 receptor (IL-2R)-/HLA-DR+ T cells is known to occur during active infection with herpes viruses. To investigate the possible role of herpes viral coinfections for apoptosis in HIV infection, we focused on Epstein-Barr virus (EBV) as an example for a herpes virus usually acquired during childhood. In 10 of 12 patients with apoptosis, we found increased levels of EBV genome in PBMC and/or tissues, indicating active EBV replication. By contrast, no increased burden of EBV was found in the four HIV-infected patients without apoptosis or in the controls. Our data indicate that in children the occurrence of apoptosis in HIV infection is closely related to activation of CD8+ T cells. Furthermore, primoinfection with or reactivation of herpes viruses, such as EBV, may substantially contribute to such T-cell activation and the ensuing apoptosis. Additional studies are warranted to evaluate the contribution of herpes virus-triggered apoptosis to the T-cell loss leading to the acquired immunodeficiency syndrome. 相似文献
86.
José GM Hofhuis Henk F van Stel Augustinus JP Schrijvers Johannes H Rommes Jan Bakker Peter E Spronk 《Critical care (London, England)》2009,13(1):118-3
During recent years increasing attention has been given to the quality of survival in critical care. Health-related quality
of life (HRQOL) is an important issue both for patients and their families. Furthermore, admission to the intensive care unit
can have adverse psychological effects in critically ill patients. Recent studies conducted in critically ill patients have
measured HRQOL. However, usually absent from such reports are evaluations of conceptual issues, addressing factors such as
why HRQOL should be measured in critically ill patients, how to define and standardize domains of HRQOL, whether proxies can
provide useful information about HRQOL in critically ill patients, whether response shift occurs in critically ill patients,
and whether post-traumatic stress disorder (PTSD) occurs in critically ill patients. Some studies reported moderate agreement
between patients and their proxies, although lower levels of agreement may be reported for psychosocial or physical functioning.
Response shift (adaptation and change in perception) appears to be an important phenomenon and likely to be present, but it
is seldom measured when estimating HRQOL in critically ill patients. Furthermore, vigilance for symptoms of PTSD and early
interventions to prevent PTSD are needed. 相似文献
87.
ZEHRA JAFFERY M.D. ADAM B. GREENBAUM M.D. MOHAMMAD F. SIDDIQUI M.D. NEETU MAHENDRAKER M.D. VIKESH GUPTA M.D. VIDU MOKKALA M.D. UDAY KANAKADANDI M.D. ANDREW ROBBINS M.D. JAMES MCCORD M.D. 《Journal of interventional cardiology》2009,22(6):564-570
Background: Peripheral arterial disease (PAD) is associated with increased mortality. Lower extremity (LE) revascularization improves symptoms, but less is known about long‐term survival benefits of LE arterial revascularization. Methods: Two hundred and eighty‐three patients with an ankle brachial index (ABI) ≤0.9 were identified at the Veterans Administration Hospital, Danville, Illinois, and rates of LE arterial revascularization and all‐cause mortality were measured at 5 years. Results: Of 283 patients identified, 42 (15%) underwent LE revascularization including 39 surgical procedures and 18 percutaneous interventions for symptomatic PAD. Eleven (26%) patients underwent repeat procedures over the 5 years of follow‐up. Those undergoing revascularization were more often Caucasian (95% vs. 79%, P = 0.01) and had lower ABIs (ABI ≤ 0.4, 45% vs. 17%, P = <0.001). At 44 ± 19 months follow‐up, there were fewer deaths in patients that underwent revascularization compared to patients who did not undergo revascularization; 10/42 (24%) versus 107/241 (44%) patients, P = 0.012. In a multivariate model LE arterial revascularization was associated with a trend toward lower all‐cause mortality (HR 0.51 [95% CI 0.26–1.02], P = 0.056). Independent predictors of mortality were age ≥65 years (HR 2.42 [95% CI 1.52–3.85], P < 0.001), history of coronary artery disease (HR 1.67 [95% CI 1.13–2.46], P = 0.010), chronic kidney disease (HR 1.75 [95% CI 1.15–2.67], P = 0.010), and an ABI ≤ 0.4 (HR 1.88 [95% CI 1.19–2.96], P = 0.006). Conclusion: Few patients at this center with LE‐PAD underwent arterial revascularization. After adjusting for baseline differences, there is a trend toward lower 5‐year mortality in those undergoing LE arterial revascularization when compared to those who do not. 相似文献
88.
89.
A Lacout M El Hajjam C Julie P Lacombe JP Pelage 《Journal of Medical Imaging and Radiation Oncology》2008,52(6):580-582
We report the case of a patient with a single liver metastasis of a mucinous colonic carcinoma that mimics a haemangioma in T2‐weighted sequences. Although a very high T2 signal in non‐cystic lesions is highly specific for the diagnostic of haemangioma, the use of gadolinium‐enhancement MRI is recommended. In patients with a history of neoplasia, the diagnosis of benign liver nodules should be made with caution. 相似文献
90.
ABSTRACT. Sixty of 68 consecutive patients detected during the first two years of the Swedish screening programme for congenital hypothyroidism were Griffiths tested at the age 6.5–7.5 years. The test quotients of the patients could not be distinguished from those of reference population. Replacement therapy with 8.7 ± 2.8 μg of l -thyroxine (mean±SD)/kg/d had been started at 15.0 ± 7.1 days of life. Furthermore, normal results on Griffiths tests were also found in 13 patients with delayed normalization of serum TSH, i.e. ≥ 19 mU/l at the age of six weeks, as well as in patients with retarded skeletal maturity and/or very low neonatal serum levels of thyroxine, i.e. < 18 nmol/l and tri-iodothyronine, i.e. <0.92 nmol/l. Our findings indicate that replacement dose of 6–11 μg l -thyroxine/kg/d is adequate and allows normal psychological development if treatment is started early. 相似文献