全文获取类型
收费全文 | 3209篇 |
免费 | 450篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 111篇 |
妇产科学 | 39篇 |
基础医学 | 420篇 |
口腔科学 | 90篇 |
临床医学 | 312篇 |
内科学 | 682篇 |
皮肤病学 | 102篇 |
神经病学 | 281篇 |
特种医学 | 294篇 |
外科学 | 436篇 |
综合类 | 80篇 |
一般理论 | 4篇 |
预防医学 | 329篇 |
眼科学 | 60篇 |
药学 | 235篇 |
1篇 | |
肿瘤学 | 207篇 |
出版年
2021年 | 40篇 |
2020年 | 40篇 |
2019年 | 39篇 |
2018年 | 56篇 |
2017年 | 30篇 |
2016年 | 43篇 |
2015年 | 48篇 |
2014年 | 62篇 |
2013年 | 114篇 |
2012年 | 117篇 |
2011年 | 124篇 |
2010年 | 126篇 |
2009年 | 96篇 |
2008年 | 104篇 |
2007年 | 115篇 |
2006年 | 111篇 |
2005年 | 126篇 |
2004年 | 113篇 |
2003年 | 104篇 |
2002年 | 94篇 |
2001年 | 79篇 |
2000年 | 93篇 |
1999年 | 92篇 |
1998年 | 116篇 |
1997年 | 104篇 |
1996年 | 82篇 |
1995年 | 82篇 |
1994年 | 64篇 |
1993年 | 70篇 |
1992年 | 78篇 |
1991年 | 67篇 |
1990年 | 64篇 |
1989年 | 78篇 |
1988年 | 87篇 |
1987年 | 68篇 |
1986年 | 57篇 |
1985年 | 76篇 |
1984年 | 41篇 |
1983年 | 52篇 |
1982年 | 34篇 |
1981年 | 38篇 |
1980年 | 27篇 |
1979年 | 33篇 |
1978年 | 35篇 |
1977年 | 44篇 |
1976年 | 31篇 |
1975年 | 35篇 |
1972年 | 16篇 |
1971年 | 23篇 |
1970年 | 26篇 |
排序方式: 共有3689条查询结果,搜索用时 15 毫秒
61.
BACKGROUND: In young adults it can be difficult to differentiate between an early bipolar illness and borderline personality disorder. There are considerable areas of clinical overlap between cyclothymic temperament, bipolar-spectrum disorders and borderline characteristics. The aim of this study was to measure borderline characteristics in young adults during an index depressive episode and to compare three diagnostic groups: DSM-IV bipolar affective disorder (BPAD); bipolar spectrum disorder (BSD); and DSM-IV recurrent major depressive disorder (MDD). METHODS: Eighty-seven young adults with a current episode of major depression and at least one previous episode of depression were recruited from consecutive referrals to a psychiatric clinic. Diagnoses were based on the Structured Clinical Interview for DSM-IV (SCID-1) and recently proposed structured diagnostic criteria for BSD. All patients also completed the borderline questions from the screening questionnaire of the International Personality Disorders Examination (IPDE). RESULTS: Diagnostically, the cohort of 87 patients divided into three groups: 14 with BPAD; 27 with BSD; and 46 with MDD. None of the subjects fulfilled DSM-IV or ICD-10 diagnostic criteria for personality disorder and all three groups were well matched in terms of age, gender distribution, ethnicity, socioeconomic and educational status, age at onset of illness, and severity of index depressive episode. Both of the bipolar-depressed groups reported significantly higher median levels of borderline characteristics than the MDD group (p<0.0001). Three of the borderline characteristics emerged as potentially useful in differentiating bipolar depression from unipolar depression: 'I've never threatened suicide or injured myself on purpose' (sensitivity=0.93; positive predictive value [PPV]=56.7); 'I have tantrums or angry outbursts' (sensitivity 0.66; PPV=65.6%); and 'Giving in to some of my urges gets me into trouble' (sensitivity=0.76; PPV=59.6%). LIMITATIONS: All of the subjects were recruited from a university health service clinic and as such are unlikely to be representative of patients from more diverse socio-economic backgrounds. No structured diagnostic assessment of personality disorder was administered. The diagnostic criteria for BSD are not yet fully validated. CONCLUSIONS: Young adults with bipolar depression exhibit significantly higher levels of borderline personality pathology than those with unipolar depression. Those borderline screening questions that reflect cyclothymic characteristics or depressive mixed states may be of practical use to clinicians in helping to differentiate between bipolar depression and unipolar depression in young adults. 相似文献
62.
Detecting pre-ovulatory luteinizing hormone surges in urine 总被引:2,自引:1,他引:2
Kesner JS; Knecht EA; Krieg EF Jr; Wilcox AJ; O'Connor JF 《Human reproduction (Oxford, England)》1998,13(1):15-21
The study objectives were to determine (i) if pre-ovulatory luteinizing
hormone (LH) surges, undetected in urine by two immunoradiometric assays
(IRMA), were detectable by an ultrasensitive immunofluorometric assay
(IFMA) and (ii) the influence of creatinine adjustment on the detection and
timing of the urinary LH surges. Daily urine specimens were contributed by
healthy 25-36 year old volunteers during 14 ovulatory menstrual cycles for
an epidemiological study conducted in 1983-1985. Specimens were selected as
having been previously assayed by two IRMA without consistently detecting
LH surges. These urine specimens were remeasured using an IFMA and adjusted
for creatinine concentration. IFMA measurements revealed unambiguous LH
surges in all cycles. Adjusting IRMA urinary LH values for creatinine
concentrations revealed previously undetected LH surges in four of eight
cycles. Creatinine adjustment also altered the timing of IRMA and IFMA LH
surges by 1-5 days. These results demonstrate an IFMA that detects pre-
ovulatory LH surges in unpreserved, frozen urine from cycles where such
surges were previously undetectable. Further, creatinine adjustment can
markedly affect detection and timing of the onset and peak of the urinary
LH surge. While our analysis suggests that this adjustment improves the
validity of the LH measure, this requires further investigation.
相似文献
63.
We performed a randomized doubled-blind study to evaluate whether there was a benefit in delay in tourniquet deflation with intra-articular administration of morphine and bupivacaine following operative arthroscopic surgery. In 34 patients the tourniquet was deflated immediately and in 38 patients the tourniquet remained inflated for 10 min following injection. The analgesic efficacy was assessed using pain scores and the amount of supplementary analgesia required. The results demonstrate no benefit in delay in tourniquet deflation. 相似文献
64.
65.
66.
Previous research indicates a role of pheromones in novel male-induced early pregnancy disruptions. Although some reports suggest that urine alone is sufficient to produce this effect, others raise procedural concerns and fail to replicate such effects. On Days 1 to 5 after insemination, female CF-1 mice had their nasal regions repeatedly painted with water, urine from males housed in isolation, or urine from males housed in proximity to females. Almost all (87.5%) of the control females delivered litters. There was a small nonsignificant reduction in proportion parturient (78.5%) among females exposed to urine of males housed without social contact. The proportion of females parturient (57.1%) after treatment with urine from males housed in proximity to females was significantly different from controls. The magnitude of the effect of socially stimulated male urine is substantially less than that recorded when males are housed directly above inseminated females separated by a wire-mesh grid. These data suggest that production of pregnancy-disrupting male pheromones is stimulated by contact with conspecifics. 相似文献
67.
The present study was a longitudinal study of age-related changes in performance of the 5-choice serial reaction time task, a test of visual attention. Following acquisition of the task, animals were tested on two occasions on their ability to perform the 5-choice task. In Test 1 (Young: 7 months; Aged: 13–14 months) no age-related effects on baseline performance were revealed. However, increasing the attentional load of the task revealed an impairment in choice accuracy by animals of the Aged group. In Test 2 (Young: 10–11 months; Aged 23–24 months), animals of the Aged group were significantly impaired on the baseline schedule of the task compared to the Young group. The deficit in accuracy on the task could be improved in the Aged animals by decreasing the attentional load. The results of the present study suggest a deficit in attentional function as a result of the aging process, markedly similar to that observed following lesions of the basalo-cortical cholinergic system. 相似文献
68.
69.
H. Lode P. Magyar J. F. Muir U. Loos K. Kleutgens 《Clinical microbiology and infection》2004,10(6):512-520
A double-blind, double-dummy, multicentre, multinational, parallel-group study was designed to establish proof of equivalence between oral gatifloxacin and oral co-amoxiclav in the treatment of 462 patients with mild-to-moderate community-acquired pneumonia. Eligible patients were randomised equally to either gatifloxacin 400 mg once-daily plus matching placebo for 5-10 days, or amoxycillin 500 mg + clavulanic acid 125 mg three-times-daily for 5-10 days. The primary efficacy endpoint was clinical response (clinical cure plus improvement) at the end of treatment. Overall, a successful clinical response was achieved in 86.8% of gatifloxacin-treated patients, compared with 81.6% of those receiving co-amoxiclav, while corresponding rates of bacteriological efficacy (eradication plus presumed eradication) were 83.1% and 78.7%, respectively. The safety and tolerability profile of gatifloxacin was comparable to that of co-amoxiclav, with adverse gastrointestinal events, e.g., diarrhoea and nausea, being the most common treatment-related adverse events in both groups. The study showed no evidence of gatifloxacin-induced phototoxicity, musculoskeletal disorders, or hepatic and renal problems. Overall, this study showed that gatifloxacin was equivalent clinically to a standard course of co-amoxiclav in patients with community-acquired pneumonia, and that gatifloxacin was safe and well-tolerated. 相似文献
70.
S I Firshein L W Hoyer J Lazarchick B G Forget J C Hobbins L P Clyne F A Pitlick W A Muir I R Merkatz M J Mahoney 《The New England journal of medicine》1979,300(17):937-941
Prenatal diagnosis of classic hemophilia (hemophilia A) in mid-trimester was achieved by means of immunoradiometric assays for factor VIII on fetal plasma and amniotic-fluid mixtures obtained by fetoscopy. Samples were analyzed from six male fetuses at risk for severe hemophilia and from nine control fetuses for which fetoscopy was carried out to attempt prenatal diagnosis of other genetic disorders. The factor VIII coagulant-antigen values for the control (non-hemophilic) samples were 17 to 94, and the factor VIII related-antigen concentrations were 50 to 155 U per deciliter. Three of the fetuses at risk for hemophilia had factor VIII values in the control range, and these infants were normal at birth. The other three fetuses had low concentrations of factor VIII coagulant antigen but normal concentrations of factor VIII related antigen. These values and the diagnoses of severe hemophilia were confirmed with blood from the abortuses. 相似文献