全文获取类型
收费全文 | 191330篇 |
免费 | 15161篇 |
国内免费 | 6369篇 |
专业分类
耳鼻咽喉 | 2133篇 |
儿科学 | 4222篇 |
妇产科学 | 4784篇 |
基础医学 | 24900篇 |
口腔科学 | 5104篇 |
临床医学 | 18167篇 |
内科学 | 30612篇 |
皮肤病学 | 3200篇 |
神经病学 | 11367篇 |
特种医学 | 7117篇 |
外国民族医学 | 30篇 |
外科学 | 23953篇 |
综合类 | 20909篇 |
现状与发展 | 13篇 |
一般理论 | 36篇 |
预防医学 | 14805篇 |
眼科学 | 4782篇 |
药学 | 18258篇 |
53篇 | |
中国医学 | 6530篇 |
肿瘤学 | 11885篇 |
出版年
2023年 | 1300篇 |
2022年 | 2350篇 |
2021年 | 4589篇 |
2020年 | 3497篇 |
2019年 | 3341篇 |
2018年 | 3977篇 |
2017年 | 3666篇 |
2016年 | 3451篇 |
2015年 | 4739篇 |
2014年 | 6122篇 |
2013年 | 6983篇 |
2012年 | 9905篇 |
2011年 | 10373篇 |
2010年 | 7379篇 |
2009年 | 6388篇 |
2008年 | 8161篇 |
2007年 | 8246篇 |
2006年 | 7999篇 |
2005年 | 6820篇 |
2004年 | 5941篇 |
2003年 | 5471篇 |
2002年 | 4764篇 |
2001年 | 8418篇 |
2000年 | 8177篇 |
1999年 | 6616篇 |
1998年 | 2327篇 |
1997年 | 1929篇 |
1996年 | 1332篇 |
1995年 | 1192篇 |
1994年 | 1096篇 |
1992年 | 3871篇 |
1991年 | 3938篇 |
1990年 | 3661篇 |
1989年 | 3638篇 |
1988年 | 3500篇 |
1987年 | 3335篇 |
1986年 | 3137篇 |
1985年 | 2990篇 |
1984年 | 2064篇 |
1983年 | 1809篇 |
1979年 | 1911篇 |
1978年 | 1186篇 |
1975年 | 1190篇 |
1974年 | 1358篇 |
1973年 | 1412篇 |
1972年 | 1355篇 |
1971年 | 1243篇 |
1970年 | 1136篇 |
1969年 | 1113篇 |
1968年 | 1023篇 |
排序方式: 共有10000条查询结果,搜索用时 625 毫秒
101.
102.
OBJECTIVES: To assess the effectiveness and safety of additional bedtime H2‐receptor antagonists (H2RAs) in suppressing nocturnal gastric acid breakthrough (NAB) via a systematic review. METHODS: Eligible trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 2, 2004), MEDLINE (January 1966–June 2004), EMBASE (January 1980–June 2004) and CINAHL (January 1982–June 2004). Additional hand‐searching was conducted on the proceedings of correlated conferences, eight important Chinese journals and references of all included trials. All randomized controlled trials evaluating H2RAs for the control of NAB were eligible for inclusion. The systematic review was conducted using methods recommended by The Cochrane Collaboration. RESULTS: Only two randomized crossover studies, comprising 32 participants, met the inclusion criteria. Because the design, dosage and duration of the treatments were different between the studies, it was not possible to conduct meta‐analysis. There were no consistent conclusions found between the two included studies in evaluating H2RAs for the control of NAB. CONCLUSIONS: No implications for practice at this stage can be concluded. Appropriately designed large‐scale randomized controlled trials with long‐term follow up are needed to determine the effects of additional bedtime H2RAs in suppressing NAB. 相似文献
103.
G Steinitz M C Martín N Gazit-Yaari M L Quesada J de la Nuez R Casillas U Malik Z B Begin 《Applied radiation and isotopes》2006,64(4):520-524
Multi-day signals, generally with duration of 2-10 days, are a prominent temporal variation type of radon (Rn) in geogas in the unsaturated zone. Rare multi-day Rn signals have been found which are characterized by: (a) a declining limb lasting up to 10 days which conforms to the radioactive decay of Rn, (b) recurs at the same location and (c) is recorded in diverse situations-volcanic and seismogenic. It suggested that a Rn blob is injected at a lower level on a steady upward flow of geogas whereby the rise and final fall of the signal are attributed to the edges of the blob while the central Rn-decay segment records the passing of the decaying blob itself. Rn-decay signals are a small subset of multi-day Rn signals which are considered as highly irregular and unusable for the understanding of geophysical processes. In difference, it is concluded that multi-day Rn signals are probably proxies of subtle geodynamic processes at upper crustal levels and are therefore significant for studying such processes. 相似文献
104.
Objective To investigate the relationship between degree of endometrioma adhesions and clinical feature, surgical treatment and postoperative recurrence. Methods From Jan 2003 to Mar 2008, 662 patients with endometrioma undergoing laparoscopic ovarian endometrioma excision in Peking Union Medical College Hospital were studied retrospectively. All patients were classified into four groups according to the extent of adhesions: 31 cases in none adhesions group, 123 cases in mild adhesions group (filmy thickness, avascular, easily separated adhesions), 310 cases in moderate adhesions group (less than a half of ovary was adjacent to dense thickness adhesions which was difficult to separate, or above a half of ovary were adjacent to filmy thickness adhesions) and 198 cases in severe adhesions group (above a half of ovary was adjacent to dense thickness, well vascularized adhesions which was difficult to separate, and always involved the other pelvic organs, observed angiogenesis). The comparison of degree, characteristics, period of pain, lab test, surgical management and postoperative recurrence was performed among those above groups. In the mean time, risk factors and multinomial logistic regression were analyzed. Results (1)Clinical characteristics: The incidence of patients with dysmenorrhea, dyspareunia, straining feeling in anus, chronic pelvic pain and the level of CA125 (>35 kU/L) was remarkably higher in moderate-to-severe adhesion groups than in none-to-mild adhesions groups (P=0.000, 0.000, 0.001, 0.006 and 0.000, respectively). Infertility rate were significantly higher in severe adhesions group(15.7%,31/198) than none adhesions group(3.2%,1/31), mild adhesions group(11.4%,14/123) and moderate adhesions group(9.7%,30/310, OR=1.728, P<0.05).(2)Operating time and blood loss: Operating time of each groups was as followed: (37±15) min in none adhesions group, (42±19) min in mild adhesions group, (50±20) min in moderate adhesions group and (63±22) min in severe adhesion group. Blood loss was (23±12) ml in none adhesion group, (31±27) ml in mild adhesion group, (40±32) ml in moderate adhesion group and (70±67) ml in severe adhesions group. Thicker adhesions result in longer operation time and more blood loss. (3)Combined with other disease: The ratio of patients who combined with adenomyosis or deeply infiltrating endometriosis in moderate-to-severer adhesion groups was higher than patients in none-to-mild adhesions groups (OR=3.466, P=0.000). (4) Postoperative recurrence: It was categorized into recurrence of pain and cyst. Moderate-to-severe adhesions was related to higher recurrence rate of pain (OR=1.685,P=0.046), but was irrelevant to recurrence of cyst. Conclusion The more extent of endometrioma adhesions was related to severer pelvic pain symptoms, longer operating time and more blood loss. Postoperative pain recurrence rate was observed in moderate-to-severe adhesion group. Extent of adhesions was irrelevant to cyst recurrence. 相似文献
105.
通过分析中国马拉松运动员ACE基因I/D多态频率分布特征,探讨其作为杰出耐力基因标记的可行性。选择我国马拉松健将、国际健将级运动员26名作为马拉松运动员组,汉族学生216名作为对照组。对两组受试者进行ACE基因I/D多态性测定。结果显示:我国马拉松运动员组的等位基因频率和基因型频率与对照组比较无显著差异,其中15名国际健将中无一DD型纯合子,提示我国优秀马拉松运动员的纯合子DD型频率低下是其ACE基因多态频率分布的主要特征。 相似文献
106.
107.
108.
109.
Background Percutaneous abdominal aortic aneurysm(AAA) repair has been previously described using the "preclose"technique and general endotrachial anesthesia (GA). 相似文献
110.
S Dvorakova E Vaclavikova A Ryska J Cap P Vlcek J Duskova D Kodetova V Holub Z Novak B Bendlova 《Experimental and clinical endocrinology & diabetes》2006,114(4):192-196
Medullary thyroid carcinoma (MTC) is a rare form of thyroid cancer representing about 10% of all thyroid malignancies. It occurs mostly as a sporadic tumor or in association with autosomal dominant inherited cancer syndromes--multiple endocrine neoplasia (MEN) types 2A and 2B and familial MTC. Germline mutations in exons 8, 10, 11, 13, 14, 15 and 16 of the RET proto-oncogene are found in most of the familial cases. There are only a few published data reporting multiple germline mutations in the RET proto-oncogene. We have detected double germline mutations in 2 different exons on the same RET allele in two MEN 2 families. In the MEN 2A family, double germline mutation in exons 10 (Cys620Phe) and 13 (Tyr791Phe) was detected. In the MEN 2B family, beside the classical germline mutation in exon 16 (Met918Thr) a second germline mutation in exon 13 (Tyr791Phe) was found. This study revealed that MEN 2 syndromes can also be caused by double germline mutations in the RET proto-oncogene and these families can be added to small worldwide cohort of families with multiple germline mutations. 相似文献