全文获取类型
收费全文 | 2637116篇 |
免费 | 199244篇 |
国内免费 | 4989篇 |
专业分类
耳鼻咽喉 | 37789篇 |
儿科学 | 83925篇 |
妇产科学 | 76060篇 |
基础医学 | 371006篇 |
口腔科学 | 79553篇 |
临床医学 | 229096篇 |
内科学 | 512031篇 |
皮肤病学 | 58373篇 |
神经病学 | 212631篇 |
特种医学 | 105318篇 |
外国民族医学 | 879篇 |
外科学 | 403730篇 |
综合类 | 64339篇 |
现状与发展 | 9篇 |
一般理论 | 918篇 |
预防医学 | 195791篇 |
眼科学 | 62109篇 |
药学 | 199349篇 |
7篇 | |
中国医学 | 5390篇 |
肿瘤学 | 143046篇 |
出版年
2018年 | 24047篇 |
2015年 | 24240篇 |
2014年 | 33660篇 |
2013年 | 51626篇 |
2012年 | 68627篇 |
2011年 | 72533篇 |
2010年 | 43078篇 |
2009年 | 41247篇 |
2008年 | 69666篇 |
2007年 | 74523篇 |
2006年 | 75499篇 |
2005年 | 73426篇 |
2004年 | 71905篇 |
2003年 | 69338篇 |
2002年 | 68136篇 |
2001年 | 122296篇 |
2000年 | 126048篇 |
1999年 | 107350篇 |
1998年 | 29261篇 |
1997年 | 26614篇 |
1996年 | 26102篇 |
1995年 | 25090篇 |
1994年 | 23587篇 |
1993年 | 22129篇 |
1992年 | 86561篇 |
1991年 | 83934篇 |
1990年 | 82176篇 |
1989年 | 80078篇 |
1988年 | 74556篇 |
1987年 | 73399篇 |
1986年 | 70078篇 |
1985年 | 67224篇 |
1984年 | 50358篇 |
1983年 | 43236篇 |
1982年 | 25665篇 |
1981年 | 23211篇 |
1980年 | 21748篇 |
1979年 | 48270篇 |
1978年 | 34031篇 |
1977年 | 29065篇 |
1976年 | 26820篇 |
1975年 | 29305篇 |
1974年 | 35464篇 |
1973年 | 34209篇 |
1972年 | 32028篇 |
1971年 | 30117篇 |
1970年 | 28131篇 |
1969年 | 26724篇 |
1968年 | 24848篇 |
1967年 | 22376篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
95.
T. Svara M. Gombac M. Vrecl P. Juntes R. Kostanjsek A. Pogacnik M. Pogacnik 《Transboundary and Emerging Diseases》2006,53(1):26-29
Clinicopathological and electron microscopical findings of eight cases of enzootic nasal adenocarcinoma of sheep, diagnosed solely in one big flock in Slovenia between years 2001 and 2003 are described. All affected sheep were female, their mean age was 4.5 ± 1.5 years and they either belonged to the Istrian pramenka breed (five sheep) or were crossbreeds (three sheep). Tumours that arose from the ethmoid area of the nasal cavity were unilateral in six cases (75%) and bilateral in two cases (25%). All tumours were classified as adenocarcinomas by histopathological examination and they displayed either a combination of tubular and papillary growth or less often solely tubular proliferation. No metastases were detected in regional lymph nodes, brain or other organs. Electron microscopical studies performed on the reprocessed paraffin‐embedded tissues revealed the presence of the virus‐like particles with an average diameter between 70 and 90 nm. 相似文献
96.
97.
98.
A new semi-empirical formula for the evaluation of (n,(3)He) reaction cross-sections at the energy of 14.6 and 20 MeV is presented. Formula was derived using the analytical expression for the evaluation of the (3)He spectrum within the frame of pre-equilibrium exciton model. The systematics obtained is compared with the empirical formula for the (n,(3)He) reaction cross-section. 相似文献
99.
Systems of care (SOCs) have been developed throughout the country to meet the needs of children with severe emotional disturbances (SED) and their families. In these SOCs, multiple agencies and disciplines are expected to work together with informal community supports to address families' needs (Stroul & Friedman, 1986a). A review of the literature on the impact of SOCs suggests: (a) communities' service delivery systems change; and (b) children experience modest improvements in symptomatology and functioning. At the same time, little is known about (a) which components of the SOC approach, at what levels, are necessary to impact child and family outcomes; (b) the degree to which SOCs affect other family members, beyond the target child; and (c) the impact of community contexts and supports in SOCs. Future research should improve measurement of key SOC constructs, examine the relation between specific levels of implementation and outcomes for the entire family, and investigate the impact of broader community systems and supports on families within SOCs. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 655–674, 2004. 相似文献
100.
Mahmoud R Hussein Dalia A Elsers Sabah A Fadel Abd-Elhady M Omar 《European journal of cancer prevention》2006,15(1):64-68
Although melanocytic skin lesions have been recognized since antiquity, their literature was limited to Caucasians. To date, the clinicopathologic features of these lesions in Egyptians are still unknown. To define these features, diagnostic records of the melanocytic skin lesions received at the Pathology Department, Assuit University Hospitals (1989-2004) were reviewed. The lesions examined included 12 benign naevi (BN), 10 dysplastic naevi (DN), and 21 cutaneous malignant melanomas (CMMs). The DN and CMMs were more common in men than in women (2 : 1 and 1.5 : 1, respectively) while BN were more common in women (2 : 1). The average age incidence was 33+/-5, 38+/-7 and 54+/-3 years, for BN, DN and CMM, respectively. The lower limb (13/21, 62%), head and neck (7/21, 33%) were the most common sites for CMMs. The average size (mm) was 2+/-0.3, 4+/-0.6 and 21+/-0.3 for BN, DN and CMMs, respectively. Recurrence occurred in 10% of CMMs. Histologically, CMMs were of nodular type and composed of epithelioid (7/21, 33%), spindle cells (1/21, 5%), or mixed cells (13/21, 62%). The mean tumour thickness (Breslow) was 6+/-0.5 mm. CMMs included two of 21(9%), three of 21(14%), six of 21(38%), and 10 of 21(38%) with Clark level II, III, IV and V. In Egypt, CMM is the third most common cutaneous neoplasm following squamous and basal cell carcinomas. Compared with Western societies, melanoma has a male sex predilection, similar histological features but different topographical distribution and rare incidence. The striking difference from Western series is the incidence of nodular melanoma - in the West this represents 15-30% of melanomas, with superficial spreading being the majority. Another key difference from the West is the 'sun-bed' culture of the West and the desire to have suntans. This is the first study that reports the clinicopathologic features of melanocytic skin lesions in Egypt. 相似文献