全文获取类型
收费全文 | 1606360篇 |
免费 | 106459篇 |
国内免费 | 3519篇 |
专业分类
耳鼻咽喉 | 23279篇 |
儿科学 | 48944篇 |
妇产科学 | 44639篇 |
基础医学 | 225145篇 |
口腔科学 | 46583篇 |
临床医学 | 133487篇 |
内科学 | 322714篇 |
皮肤病学 | 38094篇 |
神经病学 | 130123篇 |
特种医学 | 61240篇 |
外国民族医学 | 555篇 |
外科学 | 242294篇 |
综合类 | 32283篇 |
现状与发展 | 6篇 |
一般理论 | 503篇 |
预防医学 | 117060篇 |
眼科学 | 36464篇 |
药学 | 118668篇 |
4篇 | |
中国医学 | 3859篇 |
肿瘤学 | 90394篇 |
出版年
2021年 | 12389篇 |
2019年 | 13186篇 |
2018年 | 20018篇 |
2017年 | 14997篇 |
2016年 | 15991篇 |
2015年 | 17920篇 |
2014年 | 23872篇 |
2013年 | 36266篇 |
2012年 | 51047篇 |
2011年 | 53161篇 |
2010年 | 30279篇 |
2009年 | 28078篇 |
2008年 | 48955篇 |
2007年 | 52999篇 |
2006年 | 52524篇 |
2005年 | 51310篇 |
2004年 | 49238篇 |
2003年 | 47195篇 |
2002年 | 45960篇 |
2001年 | 70613篇 |
2000年 | 72429篇 |
1999年 | 61625篇 |
1998年 | 16162篇 |
1997年 | 14670篇 |
1996年 | 14005篇 |
1995年 | 13217篇 |
1992年 | 46117篇 |
1991年 | 44326篇 |
1990年 | 43472篇 |
1989年 | 42147篇 |
1988年 | 39413篇 |
1987年 | 38721篇 |
1986年 | 37107篇 |
1985年 | 35102篇 |
1984年 | 26305篇 |
1983年 | 22299篇 |
1982年 | 13429篇 |
1979年 | 25194篇 |
1978年 | 17970篇 |
1977年 | 15644篇 |
1976年 | 14097篇 |
1975年 | 16130篇 |
1974年 | 19122篇 |
1973年 | 18630篇 |
1972年 | 17831篇 |
1971年 | 16740篇 |
1970年 | 15887篇 |
1969年 | 15354篇 |
1968年 | 14345篇 |
1967年 | 12789篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
H M Meinck 《Der Nervenarzt》1991,62(12):762-765
The discovery of autoimmune processes in the stiff-man syndrome (SMS) not only raises questions concerning the syndrome itself, but may also lead to new insights into pathogenetic principles of neurological disorders. Autoantibodies against GAD, the GABA synthesising enzyme, may become a helpful (though not specific) diagnostic tool, and furthermore may serve as a plausible explanation for both the symptoms of the syndrome and the delayed development of type I diabetes mellitus. However, it remains unexplained why autoimmunity against such widespread inhibitory transmitter systems should induce a syndrome which by definition is confined to only a few symptoms, and for which the majority of neurological signs are regarded as exclusion criteria. It is therefore hypothesised that SMS is part of a broad spectrum of encephalomyelopathies with autoimmunity against GABAergic neurones in common, but with a heterotopic manifestation. Progressive encephalomyelitis with rigidity may be an extreme variant within this spectrum. 相似文献
992.
Differential distribution of pepsinogen II between the zones of the human prostate and the seminal vesicle 总被引:2,自引:0,他引:2
J H Reese J E McNeal E A Redwine I M Samloff T A Stamey 《The Journal of urology》1986,136(5):1148-1152
Pepsinogen II (PG II) is a gastric proenzyme which has previously been found in both human seminal fluid and the prostate gland. However, no regional distribution of PG II has been noted within the prostate nor has it been found in the seminal vesicle. Bouins-fixed sections of central zone, peripheral zone and seminal vesicle, taken from 10 prostates removed at radical prostatectomy or cystectomy, were exposed to antibody against PG II and stained using the A-B-C immunoperoxidase technique. Formalin-fixed tissue from autopsy prostates of four men in the third decade, and six cases with BPH nodules, were also examined for PG II activity. In nine of 10 seminal vesicles, and seven of 10 central zone samples, more than 50 per cent of the cells stained positive for PG II. By contrast, in nine of 10 peripheral zone samples staining was present in five per cent or less of the epithelial cells. Similarly, PG II activity in the four autopsy prostates occurred almost entirely within the central zone and ended abruptly at the boundary between the peripheral and central zones. BPH nodules contained no PG II activity. These findings provide the first evidence that the central and peripheral zones may serve different biological functions. Embryologically it is currently thought that the prostate is of endodermal origin and the seminal vesicle of mesodermal origin. The presence of large amounts of PG II in both the seminal vesicle and central zone lends support to the hypothesis of a common mesodermal origin for these two structures. 相似文献
993.
Quality of object relations versus interpersonal functioning as predictors of therapeutic alliance and psychotherapy outcome 总被引:1,自引:0,他引:1
W E Piper H F Azim A S Joyce M McCallum G W Nixon P S Segal 《The Journal of nervous and mental disease》1991,179(7):432-438
The purpose of the study was to compare an interview measure of quality of object relations to questionnaire and interview measures of recent interpersonal functioning with respect to the prediction of therapeutic alliance and psychotherapy outcome. The sample consisted of 64 patients who had received approximately 20 sessions of short-term individual psychotherapy within a controlled, clinical-trial investigation. Ratings of therapeutic alliance were provided independently by the patient and the therapist after each session. Outcome measures, which were provided by three sources (patient, therapist, and independent assessor), covered the areas of interpersonal functioning, psychiatric symptomatology, self-esteem, and life satisfaction. Quality of object relations, which characterizes the patient's lifelong pattern of relationships, was the best predictor. It was significantly related to patient-rated and therapist-rated therapeutic alliance and to patient improvement of both general symptomatology and specific target problems. The study also replicated previous studies that have reported significant relationships between therapeutic alliance and therapy outcome. The advantages of pretherapy predictors of therapy outcome, such as quality of object relations, are discussed. 相似文献
994.
Lack of effect of the calcium antagonist isradipine on cyclosporine pharmacokinetics in renal transplant patients. 总被引:1,自引:0,他引:1
L Endresen S Bergan H Holdaas T Pran B Sinding-Larsen K J Berg 《Therapeutic drug monitoring》1991,13(6):490-495
Hypertension has emerged as a frequent side effect in transplant recipients on effective doses of cyclosporine (CsA). To control hypertension in renal transplant patients, calcium channel blockers have been used; some of these, however, have been shown to cause significant increases in CsA levels. These findings point out that possible interactions of each calcium antagonist with CsA deserve investigation. We performed an open, placebo-controlled study in 12 stable renal transplant recipients to determine whether short-term isradipine influences CsA pharmacokinetics. All patients had mild to moderate hypertension and received triple immunosuppressive therapy with CsA, azathioprine, and prednisolone. Throughout a 4-week period of isradipine treatment, blood CsA levels (specific and nonspecific monoclonal antibodies) remained stable. The mean trough specific level was 121 +/- 14 micrograms/L following placebo, compared to 120 +/- 14 micrograms/L during isradipine. Corresponding non-specific values were 465 +/- 68 and 474 +/- 63 micrograms/L. Also, values for Cmax, AUC, and t1/2 were not significantly changed following 4 weeks of isradipine. Mean arterial pressure was significantly reduced at the end of the study. This study implies that isradipine does not influence CsA metabolism. Further studies should be carried out to determine its long-term effects on CsA pharmacokinetics and renal function in transplanted patients. 相似文献
995.
When human divers and experimental animals are exposed to an increasing environmental pressure, they develop the high pressure neurological syndrome (HPNS) characterized by electroencephalographic changes and sleep and behavioral disturbances. In rats, behavioral disturbances essentially include hyperlocomotor activity (HLA), tremor and myoclonia. Moreover, HLA has recently been demonstrated to be linked to a pressure-induced striatal increase of dopamine (DA). In these experiments, it was proposed to investigate in rats, at the behavioral level, the role of DA receptors in the occurrence of the pressure-induced DA disturbances. DA receptor agonists were found to induce no significant changes in the development of HLA, tremor, and myoclonia. Alternatively, HLA was found to be dramatically antagonized by the use of DA receptor antagonists (SCH 23390, sulpiride, and haloperidol), while tremor and myoclonia only decreased in SCH 23390 experiments. 相似文献
996.
997.
Mice simultaneously expressing the mutations nude and X-linked immune deficiency (xid) were previously shown to have pro-B cells and/or early pre-B cells while lacking C mu+ and surface Ig+ cells. We now report that thymus grafts restore both T cells and B cells in nude-xid mice. By the use of Thy-1 and Igh allogeneic donors it was shown that both the T and B cells were host derived. The B cells had a functional phenotype typical of xid mice. It is concluded that the maturation of xid B cells past the pro-B or early pre-B stage is T cell dependent. 相似文献
998.
D. M. Reid I. Mackay S. Wilkinson C. Miller D. G. Schuette J. Compston C. Cooper E. Duncan N. Galwey R. Keen B. Langdahl A. McLellan H. Pols A. Uitterlinden J. O’Riordan J. A. H. Wass S. H. Ralston S. T. Bennett 《Osteoporosis international》2006,17(1):125-132
Osteoporosis is a common disease with a strong genetic component characterized by reduced bone mass and an increased risk of fragility fractures. Bone mineral density (BMD) is the most important determinant of osteoporotic fracture risk, but the genes responsible for BMD regulation and fracture are incompletely defined. To enable multi-center studies to examine the genetic influences on BMD there is a requirement to standardize measurements across different manufacturers of bone densitometers, different versions of machines and different normative ranges. This paper describes a method developed to allow near-identical subjects with low age-adjusted BMD (based on Z-scores) to be recruited in 17 centers using 27 different densitometers. Cross-calibration was based on measurements using a European spine phantom circulated to all centers and measured ten times on each individual machine. From theses values an individual exponential curve, based on nominal versus observed BMD, was derived for each machine. As expected, there were large and significant variations in nominal BMD values, not only between scanners from different manufacturers but also between different versions of scanners from the same manufacturer. Hologic scanners tended to underestimate the nominal BMD, while Lunar scanners overestimated the value. Norland scanners gave mixed values over estimating BMD at the lower nominal value (0.5 g/cm2) while underestimating the value at the higher value (1.5 g/cm2). The validity of the exponential equations was tested using hip and spine measurements on 991 non-proband women from a familial osteoporosis study (FAMOS). After cross-calibration there was a considerable reduction in variation between machines. This observation, coupled with the absence of a similar reduction in variation attributable to a linear regression on age, demonstrated the validity of the cross-calibration approach. Use of the cross-calibration curves along with a standard normative range (in the case of this study, the Hologic normative range) allowed age-specific Z-scores to be used as an inclusion criterion in this genetic study, a method that will be useful for other trials where age-specific BMD inclusion criteria are required. 相似文献
999.
Raúl González-García Francisco J Rodríguez-Campo Verónica Escorial-Hernández Mario F Mu?oz-Guerra Jesús Sastre-Pérez Luis Naval-Gías José L Gil-Díez Usandizaga 《Journal of oral and maxillofacial surgery》2006,64(11):1587-1591
PURPOSE: Temporomandibular joint (TMJ) arthroscopy has been considered a safe surgical procedure in the treatment of TMJ derangement. However, it is not exempt from complications. This study evaluates the complications of arthroscopy in patients with internal derangement of TMJ. PATIENTS AND METHODS: Five hundred consecutive patients (670 joints) with TMJ derangement who underwent arthroscopy between 1995 and 2004 were retrospectively analyzed. All the patients were classified as II to V in the Wilkes classification. Lysis and lavage, electrocautery of the posterior ligament, injection of corticoids, injection of ethanolamine, myotomy of lateral pterygoid muscle attachments, myotomy and electrocautery, motor debridement, injection of sodium hyaluronate, and meniscal suture were performed in different patients. RESULTS: Complications were recognized during or immediately after the surgery. They were observed in 5 of 341 (1.26%) arthroscopies of the right TMJ and 4 of 329 (1.21%) arthroscopies of the left TMJ. A 1.34% complication rate was found in the whole series. No blood clots within the external auditory canal were observed. Bleeding within the superior TMJ space was observed in 57 cases (8.5%), 36 of them in the right TMJ and 21 in the left TMJ, but they were not considered as true complications. Lacerations of the external auditory canal were found in 2 cases (0.3%), with no cases of perforation of the tympanic membrane. Lesion of the auriculotemporal nerve was observed in a case. Paresia of the facial nerve was found in 4 cases (0.6%). Alteration of visual accuracy of the ipsilateral eye was also observed in a patient immediately after the surgery. CONCLUSION: Special care must be taken to reduce complications within the upper joint space by means of an adequate instrumentation and by paying attention to essential points of the arthroscopic technique. 相似文献
1000.
Z. Malazgirt K. Topgul S. Sokmen S. Ersin A. G. Turkcapar H. Gok N. Gonullu M. Paksoy M. Ertem 《Hernia》2006,10(4):326-330
Most of the papers published on spigelian hernia are either case reports or small retrospective series. In this prospective
multicenter study, we aimed to outline the specific features of spigelian hernias and patients’ characteristics more clearly.
Surgeons enrolled patients to be entered into the database as they diagnosed and treated the hernias at will. The baseline
and surgical outcome parameters were noted in each patient. A painful mass was the main presenting complaint in half of 34
patients. Accurate preoperative diagnosis was possible in 31 patients. Open intraperitoneal mesh repair was the preferred
technique. The mean hospital stay and time until return to normal daily activities were 4.1 and 15.6 days. Although a rare
condition, diagnosis of a spigelian hernia is not difficult once remembered. Its surgical repair seems to cause few complications
and is very well tolerated by the patient. 相似文献