全文获取类型
收费全文 | 1731833篇 |
免费 | 130127篇 |
国内免费 | 4713篇 |
专业分类
耳鼻咽喉 | 25167篇 |
儿科学 | 47096篇 |
妇产科学 | 47153篇 |
基础医学 | 247456篇 |
口腔科学 | 51862篇 |
临床医学 | 152371篇 |
内科学 | 333110篇 |
皮肤病学 | 35253篇 |
神经病学 | 135517篇 |
特种医学 | 68827篇 |
外国民族医学 | 252篇 |
外科学 | 275483篇 |
综合类 | 43753篇 |
现状与发展 | 10篇 |
一般理论 | 485篇 |
预防医学 | 124636篇 |
眼科学 | 40672篇 |
药学 | 133154篇 |
24篇 | |
中国医学 | 5057篇 |
肿瘤学 | 99335篇 |
出版年
2018年 | 17040篇 |
2016年 | 14689篇 |
2015年 | 17500篇 |
2014年 | 24131篇 |
2013年 | 35228篇 |
2012年 | 48109篇 |
2011年 | 50021篇 |
2010年 | 29681篇 |
2009年 | 27965篇 |
2008年 | 47222篇 |
2007年 | 50179篇 |
2006年 | 50717篇 |
2005年 | 48998篇 |
2004年 | 47605篇 |
2003年 | 45866篇 |
2002年 | 44365篇 |
2001年 | 84077篇 |
2000年 | 86302篇 |
1999年 | 72450篇 |
1998年 | 19150篇 |
1997年 | 17122篇 |
1996年 | 17101篇 |
1995年 | 16067篇 |
1994年 | 15076篇 |
1993年 | 13919篇 |
1992年 | 57725篇 |
1991年 | 55771篇 |
1990年 | 54398篇 |
1989年 | 52927篇 |
1988年 | 48904篇 |
1987年 | 47842篇 |
1986年 | 44928篇 |
1985年 | 43298篇 |
1984年 | 32164篇 |
1983年 | 27416篇 |
1982年 | 15738篇 |
1981年 | 14137篇 |
1979年 | 30678篇 |
1978年 | 21385篇 |
1977年 | 18172篇 |
1976年 | 16259篇 |
1975年 | 17788篇 |
1974年 | 21890篇 |
1973年 | 20845篇 |
1972年 | 19802篇 |
1971年 | 18585篇 |
1970年 | 17711篇 |
1969年 | 17053篇 |
1968年 | 15358篇 |
1967年 | 14062篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
New 2,5-dialkylpyrrolidines found in the venom of Monomorium indicum include trans-2-butyl-5-(4-pentenyl)pyrrolidine [1], trans-2-butyl-5-(6-heptenyl)pyrrolidine [4], trans-5-(5-hexenyl)-2-(4-pentenyl)pyrrolidine [6], trans-5-(6-heptenyl)-2-(5-hexenyl)pyrrolidine [8], and trans-5-heptyl-2-hexylpyrrolidine [16], whose structures were confirmed by synthesis. The concomitance of five previously reported trans-2,5-dialkyl-pyrrolidines along with small amounts of the cis isomers and N-methyl analogues makes the venom of M. indicum the most qualitatively diverse blend of alkaloids reported from an ant to date. The toxicities to termites of four of these alkaloids were determined. 相似文献
992.
Forty samples of cord blood lymphocytes were isolated from 40 normal healthy full-term newborns. The initial 20 samples were used to determine the dose-response curve of three different thymic extracts (TP-1, bovine thymic extract; TG-15-I and TG-15-II, both porcine thymic extracts) and one of renal origin (KG-1) as a control of non-lymphoid organ extract, by measuring the E-rosette T cells. Results showed that E-rosette T cells increased significantly when the thymic extract concentration was increased to 12.5 micrograms/ml. However, there was no statistical difference between TP-1, TG-15-I and TG-15-II in the increase of E-rosette-forming cells. The remaining 20 samples were preincubated with 0, 12.5, 25 or 50 micrograms/ml of thymic extracts. It was observed that the lymphoproliferation, interleukin-2 (IL-2), gamma-interferon (IFN-gamma) and tumor necrotic factor (TNF) production were all significantly increased after thymic extract treatment. No statistical difference between these three thymic preparations in the stimulation of lymphoproliferative response was found. However, among the three thymic extracts, TP-1 appears to induce the highest amounts of IL-2, IFN-gamma and TNF. Of the TG-15-I and TG-15-II, the former stimulates higher IL-2 production whereas the latter enhances IFN-gamma and TNF production. The different immunostimulating effects and potencies that these three thymic extracts showed may reflect not only the species difference but also the difference in preparation procedures. Different components in these thymic extracts may be responsible for different biological activities. Results from these comparative studies may provide useful information in future clinical trials for the treatment of the primary immunodeficiency diseases according to their pathogenesis and may also indicate a possible beneficial effect of the combination of chemotherapy and thymic extracts. 相似文献
993.
994.
T L Taylor 《Clinics in Podiatric Medicine and Surgery》1989,6(3):537-553
In summary, factors to consider in treatment are (1) the patient's age; (2) the flexibility of the condition; (3) the severity of deformity; (4) the presence of equinus; (5) abnormal shoe wear; and (6) the symptoms. When a child presents with severe flexible flatfoot one should rule out an underlying neuromuscular disorder and perform a complete biomechanical evaluation to ascertain any rotational or angular conditions of the legs that might influence the treatment. If a child is in group 1 (ages 4 to 7), a Helfet heel seat with a medial plantar wedge is usually adequate treatment. In the group II (ages 8 to 12) adolescent with flexible flatfoot, more control of the calcaneal eversion is needed. This is obtained by using a device constructed from a plaster mold taken while the foot is in neutral position. This UCBL type of device must usually extend to the metatarsal heads and be elevated on the medial and lateral sides. The group III (ages 13 to 17) adolescent usually has the additional problem of a forefoot varus, which must be controlled using a forefoot post. It is also not unusual to have to add additional wedging inside the heel of the shoe to invert the heel. 相似文献
995.
A study on the pathologic findings after recession and resection of extraocular muscles in rabbits was performed. Fibrosis of the extraocular muscles increased with time, which showed no difference between the recessed and resected muscles. Inflammation and foreign body reaction decreased with time, which showed no difference between the recessed and resected muscles. Adhesions of extraocular muscles to the sclera were observed from one month after the operation. The resected muscles showed milder adhesion to the sclera than the recessed ones. The operated extraocular muscles showed atrophies at one month, which showed no difference between the recessed and resected muscles. According to our results, when reoperation is needed, fibrosis of the extraocular muscles after recession and resection should be considered when making a decision on the amount of muscle to be recessed and resected. 相似文献
996.
997.
Mycobacterium ulcerans infection in Ashanti region, Ghana 总被引:1,自引:0,他引:1
T S van der Werf W T van der Graaf D G Groothuis A J Knell 《Transactions of the Royal Society of Tropical Medicine and Hygiene》1989,83(3):410-413
We describe a series of 96 cases of Mycobacterium ulcerans infection (Buruli ulcer) from a new endemic focus in the Afram valley, north of Agogo, in Ghana. 63 cases were children under 13 years old. Active treatment by excision and skin grafting necessitates long stays in hospital and repeated procedures. Scarring and contracture are frequent. Eyes and other vital organs may be destroyed. In its endemic foci Buruli ulcer is a serious health burden on rural populations. Research is urgently needed, especially in prevention and non-surgical management. 相似文献
998.
999.
1000.
J. J. KEUR J. P. S. CAMPBELL J. F. McCARTHY W. J. RALPH 《Journal of oral rehabilitation》1987,14(2):183-191
A sample consisting of 1135 edentulous patients with clinically healthy denture bearing areas, was examined radiologically. It appears that the diagnostic yield is high whereas the expected radiation induced risk is low. Patients should therefore be examined radiologically prior to full denture construction. 相似文献