全文获取类型
收费全文 | 42115篇 |
免费 | 4416篇 |
国内免费 | 2754篇 |
专业分类
耳鼻咽喉 | 333篇 |
儿科学 | 558篇 |
妇产科学 | 471篇 |
基础医学 | 4913篇 |
口腔科学 | 868篇 |
临床医学 | 5380篇 |
内科学 | 6268篇 |
皮肤病学 | 452篇 |
神经病学 | 1955篇 |
特种医学 | 1514篇 |
外国民族医学 | 18篇 |
外科学 | 4557篇 |
综合类 | 7020篇 |
现状与发展 | 14篇 |
一般理论 | 15篇 |
预防医学 | 3092篇 |
眼科学 | 1359篇 |
药学 | 4130篇 |
59篇 | |
中国医学 | 2441篇 |
肿瘤学 | 3868篇 |
出版年
2024年 | 170篇 |
2023年 | 785篇 |
2022年 | 1841篇 |
2021年 | 2396篇 |
2020年 | 1763篇 |
2019年 | 1529篇 |
2018年 | 1561篇 |
2017年 | 1414篇 |
2016年 | 1326篇 |
2015年 | 1973篇 |
2014年 | 2461篇 |
2013年 | 2299篇 |
2012年 | 3196篇 |
2011年 | 3536篇 |
2010年 | 2252篇 |
2009年 | 1883篇 |
2008年 | 2285篇 |
2007年 | 2222篇 |
2006年 | 2257篇 |
2005年 | 1947篇 |
2004年 | 1403篇 |
2003年 | 1242篇 |
2002年 | 1039篇 |
2001年 | 900篇 |
2000年 | 834篇 |
1999年 | 866篇 |
1998年 | 557篇 |
1997年 | 499篇 |
1996年 | 395篇 |
1995年 | 334篇 |
1994年 | 338篇 |
1993年 | 190篇 |
1992年 | 258篇 |
1991年 | 208篇 |
1990年 | 173篇 |
1989年 | 219篇 |
1988年 | 140篇 |
1987年 | 151篇 |
1986年 | 72篇 |
1985年 | 77篇 |
1984年 | 49篇 |
1983年 | 34篇 |
1982年 | 29篇 |
1981年 | 26篇 |
1980年 | 19篇 |
1979年 | 28篇 |
1978年 | 11篇 |
1975年 | 13篇 |
1974年 | 13篇 |
1968年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Gresham T Richter Jacob E Smith Horace J Spencer Chun Y Fan Emre Vural 《Otolaryngology--head and neck surgery》2007,137(2):239-242
OBJECTIVES: Histological comparison of human-based (AlloDerm) and porcine-based (ENDURAGen) dermal matrices regarding tissue incorporation and neovascularization as potential soft tissue augmentation materials. STUDY DESIGN: In vivo, rat model. METHODS: Subcutaneous implantation of 1-mm thick, 1 cm x 1 cm pieces of AlloDerm, ENDURAGen, and meshed ENDURAGen was performed in 24 Sprague Dawley rats. Implant materials were harvested at 4 (n = 12) and 8 weeks (n = 12). Histological quantification of soft tissue ingrowth and microvascular density was performed following hematoxylin-eosin staining and CD34 immunohistochemistry, respectively. RESULTS: AlloDerm showed significantly greater soft tissue ingrowth and microvascular density compared with both ENDURAGen and meshed ENDURAGen at 4 and 8 weeks (P < 0.001). CONCLUSIONS: Although these results may differ in human host tissues, AlloDerm seems to be a more suitable dermal matrix implant than ENDURAGen for cases in which tissue incorporation and neovascularization are sought for the optimal outcome based on this animal model. 相似文献
42.
目的探讨交叉韧带重建术中可吸收挤压螺钉的使用方法和疗效。方法总结53例交叉韧带重建病例使用可吸收挤压螺钉的情况,在术中、术后并发症、术后康复、膝关节功能状况等方面进行回顾性分析。结果三例出现韧带切割现象。两例股骨侧螺钉拧入后导引针无法拔出。一例挤压螺钉断裂。术后Lysholm评分平均92.4±4.1。结论交叉韧带重建术中使用可吸收挤压螺钉固定的方法固定牢固,术后恢复快,利于早期康复。 相似文献
43.
44.
急性心肌梗塞患者血清唾液酸含量测定 总被引:2,自引:0,他引:2
本文测定了50例正常人,32例急性心肌梗塞,54例冠心病无梗塞者血清SA水平,结果表明,急性心肌梗塞组血清SA水平与冠心病无梗塞组及正常人相比,具显著性差异,可能与心肌梗塞造成心肌细胞受损所致使细胞表面成份释放入血有关,所以血清SA测定可提供一新的心肌梗塞诊断依据。 相似文献
45.
戊四氮诱发大鼠全身强直-阵挛性癫痫发作诱导丘脑c-fos癌基因表达 总被引:1,自引:0,他引:1
首次运用Fos癌蛋白抗体免疫组化法详细研究了戊四氮诱发大鼠全身强直-阵挛性癫痫发作诱导丘脑c-fos癌基因表达的动态分布。主要结果是:腹腔内注入戊四氮诱导大鼠癫痫发作后0.5h,丘脑室旁核出现低密度的Fos-免疫阳性(Fos-ir)细胞核标记;3h时,中等密度的Fos-ir标记扩布至大部分丘脑中线和板内核群及网状核;6h时,所有上述丘脑核群的Fos-ir标记普遍增为中等至高密度。结合文献报道,上述结果提示:丘脑室旁核很可能是戊四氮诱发大鼠全身强直-阵挛性癫痫发作的重要起源部位之一;丘脑中线和板内核群及网状核很可能在此种癫痫发作的病理生理机制中起重要作用。 相似文献
46.
A prospective randomised clinical trial was conducted to examine the efficacy of 2 weeks pre-operative parenteral nutrition (PPN) for the prevention of complications following surgery for oesophageal cancer. Forty patients were studied, the diet of twenty being supplemented by pre-operative parenteral nutrition. There were no significant differences in age, nutritional status, tumour staging and histology between the two groups of patients. The use of PPN resulted in a significant gain in body weight and nitrogen but failed to produce an overall reduction in post-operative morbidity and mortality rates. However patients receiving PPN exhibited two types of changes in serum albumin levels. Those with a fall in serum albumin levels associated with an increase in body weight (indicating an expansion of extracellular volume) had a significantly higher incidence of post-operative pulmonary complications than the group exhibiting a rise in serum albumin levels concomitant with increase in body weight. These data suggested that two weeks PPN might not be adequate in certain patients and a longer period of PPN is required. They also show no clinical benefit from the routine use of pre-operative parenteral nutrition in all patients, but do not exclude benefit in selected groups. 相似文献
47.
Fan Xiao-Guang Zheng Zhen-Qun FAN XIAO-GUANG ZHENG ZHEN-QUN 《American journal of reproductive immunology (New York, N.Y. : 1989)》1997,37(5):359-364
PROBLEM and METHOD: Early pregnancy factor (EPF), an Immunosuppressive substance, which appears in pregnant women's sera 48 h after fertilization, is a kind of pregnancy-specific protein. To determine whether the EPF activity could be a super early indicator of pregnancy, we used rosette inhibition assay to detect EPF activity in the sera, collected from 70 women 2–7 days after ovulation intending to conceive monitored by ultrasonography. Simultaneously we selected 40 non-pregnant sera and 12 early-pregnant sera as negative control and positive control, respectively. RESULTS: The results of this study demonstrated that EPF activity is detected in 35 women's sera out of 70 women within 2–7 days after ovulation, and 28 women out of the 35 were pregnant, which was known by follow-up, and 7 were not pregnant, possibly due to either false positive results or embryo loss because of preimplantation failure, thus causing no pregnancy. The other 35 out of 70 had no EPF activity and 34 of them were not pregnant, which was known by follow-up, but one case became pregnant, which was false negative result. Our study showed that diagnosis of the super early pregnancy could be made by detecting EPF activity in maternal serum within the time of preimplantation. The accuracy of pregnancy diagnosis by this method is 88.6%, with a false negative rate of 3.4% and a false positive rate of 17.1%. The β-HCG level was measured from the above 70 women's sera in order to contrast EPF activity. All of the sera collected 2–6 days following ovulation indicated that there were lower β-HCG values in very early pregnancy (≥a5 mIU/ml). On the seventh day after ovulation, EPF activity was detected in 11 out of 15 sera with only 2 of them with a b-HCG level that reached or slightly surpassed that of the early pregnancy diagnosis (5 mIU/ml and 5.4 mIU/ml, respectively). This demonstrated that β-HCG is not the earliest signal of pregnancy; otherwise the EPF activity is one that appears 2–6 days earlier than β-HCG appears. We measured the progesterone level of the 48 sera from the 70 collected above within 2–7 days postovulation and found most of them reached the level of progesterone in the luteal phase (7.5–98.3 nmol/L). This indicated that ovulation had taken place in these women, which was in accordance with observations by ultrasonography. CONCLUSIONS: Our study showed that diagnosis (of 88.6%) of super early pregnancy could be made with an accuracy of 88.6% by detecting EPF activity in maternal serum within 2-days after ovulation. This offers a basis for pregnancy diagnosis for the women who attempt to terminate their pregnancy safely or who conceive unexpectedly, and it contributes to family-planning. 相似文献
48.
49.
胆总管的矢状断层解剖研究 总被引:1,自引:0,他引:1
在30套成人腹部连续矢状断层标本上,胆总管与下腔静脉主要出现于R2-R3断层;胆总管胰腺段与胰头的关系有部分包埋,完全包埋及胰腺后型;十二指肠大乳头集中出现于R3断层;胆总管的行程有4种形式。文内还探讨了矢状断层里胆总管各段的毗邻及识别标志。 相似文献
50.
本文通过28例正常人及28例癌症病患者的头发的分析,得出癌症病患者的头发区别于正常人的头发的特征是:癌症病患者的头发中含有微量元素As、Ni、Mn。 相似文献