全文获取类型
收费全文 | 932142篇 |
免费 | 66351篇 |
国内免费 | 1343篇 |
专业分类
耳鼻咽喉 | 12974篇 |
儿科学 | 24361篇 |
妇产科学 | 23259篇 |
基础医学 | 132910篇 |
口腔科学 | 28248篇 |
临床医学 | 80557篇 |
内科学 | 183469篇 |
皮肤病学 | 19227篇 |
神经病学 | 72184篇 |
特种医学 | 36801篇 |
外国民族医学 | 79篇 |
外科学 | 152079篇 |
综合类 | 18046篇 |
现状与发展 | 1篇 |
一般理论 | 234篇 |
预防医学 | 61751篇 |
眼科学 | 21307篇 |
药学 | 72553篇 |
3篇 | |
中国医学 | 2162篇 |
肿瘤学 | 57631篇 |
出版年
2018年 | 8964篇 |
2017年 | 7032篇 |
2016年 | 7762篇 |
2015年 | 8859篇 |
2014年 | 11985篇 |
2013年 | 17509篇 |
2012年 | 24096篇 |
2011年 | 25041篇 |
2010年 | 14809篇 |
2009年 | 14276篇 |
2008年 | 24606篇 |
2007年 | 25689篇 |
2006年 | 26486篇 |
2005年 | 25432篇 |
2004年 | 24565篇 |
2003年 | 23610篇 |
2002年 | 23154篇 |
2001年 | 54730篇 |
2000年 | 56556篇 |
1999年 | 46951篇 |
1998年 | 10733篇 |
1997年 | 9468篇 |
1996年 | 9594篇 |
1995年 | 8926篇 |
1994年 | 8280篇 |
1993年 | 7595篇 |
1992年 | 35499篇 |
1991年 | 33922篇 |
1990年 | 32751篇 |
1989年 | 31880篇 |
1988年 | 28999篇 |
1987年 | 28265篇 |
1986年 | 26303篇 |
1985年 | 25161篇 |
1984年 | 17843篇 |
1983年 | 15145篇 |
1982年 | 7802篇 |
1981年 | 6775篇 |
1979年 | 15799篇 |
1978年 | 10605篇 |
1977年 | 9060篇 |
1976年 | 7872篇 |
1975年 | 8632篇 |
1974年 | 10470篇 |
1973年 | 9866篇 |
1972年 | 9360篇 |
1971年 | 8854篇 |
1970年 | 8428篇 |
1969年 | 7926篇 |
1968年 | 7203篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
951.
Brain abscess in the 1980s 总被引:1,自引:0,他引:1
F E Donald J L Firth I M Holland D T Hope P Ispahani J A Punt 《British journal of neurosurgery》1990,4(4):265-271
Brain abscess was reviewed in 24 patients admitted to University Hospital, Nottingham over a period of 3 years. Chronic ear infection was the most common predisposing factor, but in 11 patients the focus of infection remained unknown. CT scanning, carried out in all patients, was negative in one patient with clinical signs of meningitis. Polymicrobial and anaerobic infections were common. Actinomyces species were isolated in mixed culture from seven patients; in five the abscess was located in the cerebellum. Therapy was most often a combination of surgical drainage and antimicrobial therapy with beta-lactam agents and metronidazole. Evidence suggests that cefotaxime may offer a suitable alternative to chloramphenicol and benzylpenicillin in the treatment of brain abscess. 相似文献
952.
M T Khan C S McKinstry K E Bell T F Fannin D P Byrnes R Vasishta 《British journal of neurosurgery》1990,4(3):217-223
Giant serpentine aneurysms form a subgroup of giant intracranial aneurysms with specific radiological and surgical features. Previous reports have stressed the predilection of these lesions for the carotid circulation, particularly the middle cerebral artery. Two cases of serpentine aneurysm affecting the posterior circulation are reported and the problems of diagnosis and treatment of this lesion are discussed. 相似文献
953.
The aim of the present study was to investigate if distant effects could be detected within the central nervous system after impact of a high-energy missile in the left thigh of young pigs. Pressure transducers implanted in various parts of the body of the animal, including the brain, recorded a short-lasting burst of oscillating pressure waves with high frequencies and large amplitudes, traversing the body tissue with a velocity of about that of sound in water (1,460 m/s). The distance between the point of impact and the brain and cervical spinal cord is in the range of 0.5 m. Macroscopic examination revealed that there was no gross brain tissue disruption or visible blood-brain barrier dysfunction. Light microscopic examination demonstrated myelin invaginations in the largest axons and shrinkage of axoplasm. Electron microscopic examination revealed a reduction in the number of microtubules, especially in the larger axons in the brainstem. Disintegration of Nissl substance, i.e., chromatolysis, was noticed after 48 hr in many Purkinje nerve cells in the cerebellum, concomitantly with the appearance of an increased frequency of association between lamellar bodies and mitochondria. Changes could also be observed in the cervical spinal cord and, at reduced frequency and extent, in the optic nerve and in other parts of the brain. These effects were evident within a few minutes after the trauma and persisted even 48 hr after the extremity injury. It is concluded that distant effects, likely to be caused by the oscillating high-frequency pressure waves, appear in the central nervous system after a high-energy missile extremity impact. 相似文献
954.
Long-term survival in an infant with urethral atresia 总被引:2,自引:0,他引:2
Complete urethral atresia is an anomaly that previously was incompatible with life. We report on a surviving infant with this anomaly. As a fetus urinary decompression was accomplished with a vesicoamniotic shunt. Peritoneal dialysis was initiated shortly after birth and at 9 months supramembranous scrotal inlay urethroplasty was performed to provide for egress of urine from the bladder. A maternal renal allograft was performed when he was 12 months old. When the patient was 3 1/2 years old he had normal renal function and emptied the bladder to completion through the reconstructed urethra. Although mildly delayed, he continues to progress with all developmental milestones. 相似文献
955.
Pathogenesis and biological significance of seminal vesicle invasion in prostatic adenocarcinoma 总被引:2,自引:0,他引:2
A A Villers J E McNeal E A Redwine F S Freiha T A Stamey 《The Journal of urology》1990,143(6):1183-1187
Seminal vesicle invasion and the percentage involvement by cancer of each seminal vesicle were related to cancer volume, quantitative histological grade and presence or absence of lymph node metastases in 243 radical prostatectomy specimens. There were 47 prostates with seminal vesicle invasion. Frequency and extent of seminal vesicle invasion were strongly correlated with cancer volume, with minimal invasion noted in only 6% of the cases less than 4 cc. The relationship of seminal vesicle invasion to lymph node metastasis was statistically significant but cancer volume and histological grade were much stronger predictors of lymph node metastasis. The route of invasion from the prostate in 46 cases involved direct tumor spread into the midbase region near the ejaculatory ducts. Seminal vesicle invasion often may not be identified if the tissue nearest the ejaculatory ducts at the prostate base is not sampled. 相似文献
956.
We evaluated 162 high risk male patients for the presence of subclinical anogenital human papillomavirus infection with magnified penile surface scanning. Infected patients were treated as outpatients with the carbon dioxide laser under local anesthesia. Of the patients 43 were followed for a mean of 8.7 months or 2.1 treatments after the initial treatment (range 3 to 30 months). A subset of 10 patients was followed for more than 20 months or 6.2 treatments. To date a 51% recurrence rate has been observed in the over-all population and a 50% recurrence rate was noted in the 20-month followup population. In a separate arm of this study a small number of patients (15) with deoxyribonucleic acid typed subclinical intraurethral disease plus subclinical skin lesions were treated with topical carbon dioxide laser therapy for the penile lesions and adjuvant intraurethral 5% 5-fluorouracil. Mean followup in the group was approximately 4 months. The addition of intraurethral therapy in this positive human papillomavirus reservoir group had no significant effect on the high rate of human papillomavirus recurrence. 相似文献
957.
Addition of immunomodulating therapy with Thymalin, a thymus agent, to the multimodality therapy of burnt patients contributes to a rapid normalization of immunological parameters. The most marked immune response was observed 7-10 days after a therapy course initiated in the early periods of burn disease in patients with severely depressed T-system immunity and a high sensitivity to the drug. Inclusion of a donor blood leukomass transfusion course activates the cellular link of the immune system just after the treatment course, but fails to favour a stable normalization of thymus-dependent lymphocyte ratios. 相似文献
958.
The frequency of the development of rejection crises in the early postoperative period in 32 recipients of allogeneic kidneys from alive related donors was analysed depending on the histocompatibility according to the antigens of the HLA-AB system and the nature of the immunosuppressant therapy. The results of the analysis showed that the frequency of rejection crises was 100% when the donor and recipient were compatible in 1-2 antigens, and 40% in compatibility according to 3-4 antigens. The incidence of rejection crises was 71.4% among patients who received the standard immunosuppressant therapy (corticosteroids + azathioprine) and 36% among those given also sandimmune. Analysis of the frequency of rejection crises according to the ABO blood group system to which the donor-recipient pair occurred, showed that rejection crises occurred most frequently among patients with A (II) blood group. 相似文献
959.
Ia V Shparik B T Bilynski? 《Klinichna khirurhiia / Ministerstvo okhorony zdorov'ia Ukra?ny, Naukove tovarystvo khirurhiv Ukra?ny》1990,(5):16-17
In 53 patients with gastric and intestinal cancer, the content and functional activity of the natural killer cells was studied. The suppression of these indices at the first days after the operation, and restoration of their preoperative levels within 2-2.5 weeks was noted. 相似文献
960.
The role of CD4+ helper T cells in the destruction of microencapsulated islet xenografts in nod mice 总被引:4,自引:0,他引:4
C J Weber S Zabinski T Koschitzky L Wicker R Rajotte V D'Agati L Peterson J Norton K Reemtsma 《Transplantation》1990,49(2):396-404
Islet transplants for large numbers of patients with diabetes will require xenografts. Microencapsulation is an appealing method for islet xenografting. However, graft function has been limited by a cellular reaction, particularly intense in spontaneously diabetic, NOD mice. The purpose of this study was to elucidate the mechanism of this reaction. Poly-1-lysine-alginate microcapsules containing 4000-12,000 dog or 1800-2000 rat islets were xenografted intraperitoneally into streptozotocin (SZN)-diabetic C57BL/6J and NOD mice, with or without recipient treatment with GK 1.5 (anti-CD4 monoclonal antibody) (20-30 microliters i.p. every 5 days, begun on day -7. Grafts were considered technically successful if random blood glucose (BG) was normalized (less than 150 mg/dl) within 36 hr. Graft failure was defined as BG greater than 250 mg/dl. Dog and rat islets in microcapsules normalized BG in both SZN and NOD mice within 24 hr routinely. Empty microcapsules and GK 1.5 treatments alone did not affect BG. NODs destroyed both microencapsulated dog and rat islets more rapidly than did SZN-diabetic mice (P less than .01). Graft biopsies showed an intense cellular reaction, composed of lymphocytes, macrophages and giant cells, and no viable islets. GK 1.5 treatment significantly prolonged both dog-to-NOD and rat-to-NOD grafts (P less than 0.01). Biopsies of long-term functioning grafts (on days 65-85) demonstrated viable islets and no cellular reaction around microcapsules; 1/4 rat and 1/8 dog islet xenografts continued to function indefinitely in NOD recipients, even after cessation of GK 1.5 therapy. Prediabetic NODs receiving encapsulated dog or rat islets mounted a moderate cellular reaction to grafts. Empty microcapsules excited no cellular reaction in diabetic or prediabetic NODs. We conclude that the NOD reaction to microencapsulated xenogeneic islets is helper T cell-dependent, and that the target of this reaction is not the microcapsule itself, but the donor cells within. 相似文献