全文获取类型
收费全文 | 25045篇 |
免费 | 1499篇 |
国内免费 | 282篇 |
专业分类
耳鼻咽喉 | 453篇 |
儿科学 | 368篇 |
妇产科学 | 409篇 |
基础医学 | 3873篇 |
口腔科学 | 458篇 |
临床医学 | 1967篇 |
内科学 | 4740篇 |
皮肤病学 | 1076篇 |
神经病学 | 1671篇 |
特种医学 | 1820篇 |
外科学 | 3532篇 |
综合类 | 94篇 |
一般理论 | 2篇 |
预防医学 | 1077篇 |
眼科学 | 696篇 |
药学 | 2177篇 |
中国医学 | 333篇 |
肿瘤学 | 2080篇 |
出版年
2023年 | 161篇 |
2022年 | 557篇 |
2021年 | 853篇 |
2020年 | 442篇 |
2019年 | 624篇 |
2018年 | 724篇 |
2017年 | 577篇 |
2016年 | 906篇 |
2015年 | 1321篇 |
2014年 | 1521篇 |
2013年 | 1703篇 |
2012年 | 2411篇 |
2011年 | 2286篇 |
2010年 | 1472篇 |
2009年 | 1200篇 |
2008年 | 1571篇 |
2007年 | 1412篇 |
2006年 | 1259篇 |
2005年 | 1202篇 |
2004年 | 971篇 |
2003年 | 835篇 |
2002年 | 721篇 |
2001年 | 278篇 |
2000年 | 283篇 |
1999年 | 218篇 |
1998年 | 138篇 |
1997年 | 94篇 |
1996年 | 71篇 |
1995年 | 55篇 |
1994年 | 49篇 |
1993年 | 45篇 |
1992年 | 73篇 |
1991年 | 69篇 |
1990年 | 58篇 |
1989年 | 46篇 |
1988年 | 50篇 |
1987年 | 43篇 |
1986年 | 52篇 |
1985年 | 53篇 |
1984年 | 44篇 |
1983年 | 52篇 |
1982年 | 21篇 |
1981年 | 18篇 |
1980年 | 19篇 |
1979年 | 29篇 |
1978年 | 27篇 |
1977年 | 24篇 |
1976年 | 23篇 |
1974年 | 18篇 |
1973年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
11.
M W Moon 《Critical Care Nursing Clinics of North America》1992,4(3):457-465
Caring for the adolescent with HIV infection or AIDS in the critical care setting is challenging. This article discusses medical treatments for HIV, aspects of adolescent development that influence their behaviors, certain behaviors that put adolescents at risk for HIV acquisition, ethical and legal concerns for caring for this population, nursing implications for care, and the needs of nurses caring for this population. 相似文献
12.
A case of a paraffinoma in the urinary bladder is presented. Plain radiography and intravenous urography showed a low attenuation filling defect in the urinary bladder, and CT demonstrated a lobulated fat-attenuation mass floating in the urinary bladder. 相似文献
13.
The relationship of the extrinsic blood supply to regeneration in graft reconstructed peripheral nerves 总被引:3,自引:0,他引:3
A F Cook H K Moon M P Lynn D Margolin E Z Browne 《British journal of plastic surgery》1988,41(3):298-304
Median nerves of rats were reconstructed with conventional or vascular nerve grafts. After 2, 3 and 4 weeks, Allen Video-Enhanced Contrast, Differential Interference Contrast (AVEC-DIC) microscopy revealed axonal transport in most preparations, with varying degrees of myelination. Radio-isotope tracer was measured in the nerve. Two and 4 week measurements revealed no difference between the graft types. At 3 weeks the vascular graft group exhibited transport along the entire length of the nerve in contrast to a relatively abbreviated path length in the conventional graft group. Nerve conduction velocities (NCV) were measured proximal to, within and distal to the grafts. Three week NCV showed no difference between the graft types. The 4 week NCV revealed normal values in the vascular graft group at points distal to and within the graft. Significant slowing was seen in the conventional grafts at both points. 相似文献
14.
Kyung‐Sub Moon Shin Jung Jae‐Hyuk Lee Tae‐Young Jung In‐Young Kim Soo‐Han Kim Sam‐Suk Kang 《Neuropathology》2006,26(2):141-146
We present a case of benign osteoblastoma of the occipital bone. Benign osteoblastoma is an uncommon primary bone tumor, which usually involves the vertebrae and the long bones. This tumor rarely develops in the calvaria, showing a preference for the temporal and frontal bones when it does. To the best of our knowledge, this case is only the eighth reported case of benign osteoblastoma confined to the occipital bone. A 20‐year‐old male presented with a mild tender mass lesion of the occipital area, just below the lambda. Plain X‐ray films and CT scans demonstrated an osteolytic mass surrounded by the sclerotic rim within the diploic space. MRI proved to be effective for the evaluation of the intracranial and intraosseous extensions of the tumor. However, it was very difficult to formulate a differential diagnosis against other osteoblastic tumors, or osteoid osteoma, in view of its radiological appearance. The final diagnosis was obtained by careful consideration of the histopathological characteristics of the tumor combined with its clinical and radiological features. Although generally regarded as benign, a complete resection is preferred over conventional curettage as this can guard against possible recurrence and malignant transformation. 相似文献
15.
Seung Min Lee Seung Kyung Hann Soo II Chun Seung Hung Lee Yoon-Kee Park 《The Journal of dermatology》1994,21(2):106-110
A 25-year-old female has had brown to erythematous telangiectatic patches and grouped papules on her face, neck, arm, and trunk since childhood following B.C.G. vaccination. Histopathologically, the lesions consisted of hyperkeratosis, slight acanthosis, tuberculoid granulomas with some Langerhans type giant cells in the mid-dermis. Although various forms of cutaneous tuberculosis after B.C.G. vaccination have been reported, it was difficult for us to assign the patient's skin lesion to any specific disease entity. Remission of her cutaneous lesions occurred clinically and histopathologically after treatment with isoniazid and rifampin. 相似文献
16.
17.
Performance measurement of the microPET focus 120 scanner. 总被引:6,自引:0,他引:6
Jin Su Kim Jae Sung Lee Ki Chun Im Su Jin Kim Seog-Young Kim Dong Soo Lee Dae Hyuk Moon 《Journal of nuclear medicine》2007,48(9):1527-1535
The microPET Focus 120 scanner is a third-generation animal PET scanner dedicated to rodent imaging. Here, we report the results of scanner performance testing. METHODS: A (68)Ge point source was used to measure energy resolution, which was determined for each crystal and averaged. Spatial resolution was measured using a (22)Na point source with a nominal size of 0.25 mm at the system center and various off-center positions. Absolute sensitivity without attenuation was determined by extrapolating the data measured using an (18)F line source and multiple layers of absorbers. Scatter fraction and counting rate performance were measured using 2 different cylindric phantoms simulating rat and mouse bodies. Sensitivity, scatter fraction, and noise equivalent counting rate (NECR) experiments were repeated under 4 different conditions (energy window, 250 approximately 750 keV or 350 approximately 650 keV; coincidence window, 6 or 10 ns). A performance phantom with hot-rod inserts of various sizes was scanned, and several animal studies were also performed. RESULTS: Energy resolution at a 511-keV photopeak was 18.3% on average. Radial, tangential, and axial resolution of images reconstructed with the Fourier rebinning (FORE) and filtered backprojection (FBP) algorithms were 1.18 (radial), 1.13 (tangential), and 1.45 mm full width at half maximum (FWHM) (axial) at center and 2.35 (radial), 1.66 (tangential), and 2.00 mm FWHM (axial) at a radial offset of 2 cm. Absolute sensitivities at transaxial and axial centers were 7.0% (250 approximately 750 keV, 10 ns), 6.7% (250 approximately 750 keV, 6 ns), 4.0% (350 approximately 650 keV, 10 ns), and 3.8% (350 approximately 650 keV, 6 ns). Scatter fractions were 15.9% (mouse phantom) and 35.0% (rat phantom) for 250 approximately 750 keV and 6 ns. Peak NECR was 869 kcps at 3,242 kBq/mL (mouse phantom) and 228 kcps at 290 kBq/mL (rat phantom) at 250 approximately 750 keV and 6 ns. Hot-rod inserts of 1.6-mm diameter were clearly identified, and animal studies illustrated the feasibility of this system for studies of whole rodents and mid-sized animal brains. CONCLUSION: The results of this independent field test showed the improved physical characteristics of the F120 scanner over the previous microPET series systems. This system will be useful for imaging studies on small rodents and brains of larger animals. 相似文献
18.
Although breast milk is recommended as the optimal source of infant nutrition, breastfeeding initiation is below recommended levels, especially among teenage mothers. Breastfeeding initiation rates among Michigan (US) teenage mothers (12-19 y) were compared by demographics and health behaviors. Multivariate analyses determined which factors were significant independent predictors of breastfeeding initiation among teenage mothers enrolled prenatally in the Michigan Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) program in 1995. Significant predictors independently associated with breastfeeding initiation were race/ethnicity, education, marital status, postpartum anemia status, parity, prenatal trimester of WIC enrollment, and smoking. The strongest predictor of breastfeeding initiation differed for white mothers (positive predictor: education beyond high school [OR = 3.13]) and black mothers (negative predictor: multiparous [OR = 0.25]). Initiation rates for this population of teenage mothers fall below the national average for mothers of all ages and the US Healthy People 2010 goals. Research is needed concerning how breastfeeding support and education can be improved to reach the US national health goals. 相似文献
19.
Hy De Lee Euy Young Soh Hoon Sang Chi Byong Ro Kim Kyong Sik Lee Kyung Soon Song Hyun Joo Jung 《Surgery today》1990,20(2):180-185
The relationship between primary tumor proliferative activity and clinical and pathologic characteristics was analyzed in
relation to menopausal status in 32 patients with malignant or benign breast disease. The thymidine labeling index (TLI) showed
significantly higher median values in the cancer patients (3.48 per cent) than in the patients with benign diseases (1.02
per cent). TLI was not significantly affected by delayed incubation at room temperature for about 1 hour. In the breast cancer
patients, TLI did not significantly correlate to tumor size, the presence of axillary lymph node metastasis or pathologic
nuclear grading. The only significant difference was limited to the breast cancer patients without axillary lymph node metastasis
in relation to menopausal status; the TLI in the premenopausal patients (5.10 per cent) was significantly higher (p<0.05)
than that in the postmenopausal patients (2.28 per cent). These data thus suggest that among premenopausal patients without
axillary lymph node metastasis, those with a high TLI could be potential candidates for adjuvant chemotherapy. 相似文献
20.
The sperm penetration assay is an expensive, time-consuming test to assess male fertility in vitro. Although some investigators are enthusiastic in its application, others feel that it is not sensitive or specific enough to be used as part of the routine infertility evaluation. Indeed, this bioassay is not a faithful reproduction of in vivo conditions. However, if the SPA is abnormal, it is unlikely that sperm will fertilize a human ovum in vivo. Conversely, a normal SPA does not guarantee successful in vivo fertilization. No bioassay can be absolute in its predictive value, but false-negative results must be kept to a minimum for this bioassay to be of any clinical significance. Each laboratory performing the SPA should optimize the assay for sensitivity, reproducibility, and minimization of false-negative results and then establish normal and abnormal ranges of its own. If the limitations of the SPA are kept in mind, and if we employ it very selectively, it may still be useful. 相似文献