全文获取类型
收费全文 | 11998篇 |
免费 | 847篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 235篇 |
儿科学 | 297篇 |
妇产科学 | 244篇 |
基础医学 | 1527篇 |
口腔科学 | 288篇 |
临床医学 | 1008篇 |
内科学 | 2551篇 |
皮肤病学 | 253篇 |
神经病学 | 924篇 |
特种医学 | 840篇 |
外国民族医学 | 1篇 |
外科学 | 1546篇 |
综合类 | 183篇 |
一般理论 | 11篇 |
预防医学 | 819篇 |
眼科学 | 380篇 |
药学 | 789篇 |
中国医学 | 30篇 |
肿瘤学 | 961篇 |
出版年
2023年 | 65篇 |
2022年 | 123篇 |
2021年 | 224篇 |
2020年 | 183篇 |
2019年 | 230篇 |
2018年 | 281篇 |
2017年 | 218篇 |
2016年 | 276篇 |
2015年 | 312篇 |
2014年 | 369篇 |
2013年 | 469篇 |
2012年 | 717篇 |
2011年 | 670篇 |
2010年 | 419篇 |
2009年 | 341篇 |
2008年 | 545篇 |
2007年 | 603篇 |
2006年 | 563篇 |
2005年 | 599篇 |
2004年 | 497篇 |
2003年 | 520篇 |
2002年 | 482篇 |
2001年 | 380篇 |
2000年 | 357篇 |
1999年 | 312篇 |
1998年 | 156篇 |
1997年 | 122篇 |
1996年 | 104篇 |
1995年 | 99篇 |
1994年 | 88篇 |
1993年 | 74篇 |
1992年 | 218篇 |
1991年 | 190篇 |
1990年 | 168篇 |
1989年 | 191篇 |
1988年 | 161篇 |
1987年 | 176篇 |
1986年 | 166篇 |
1985年 | 166篇 |
1984年 | 122篇 |
1983年 | 97篇 |
1982年 | 70篇 |
1981年 | 51篇 |
1980年 | 53篇 |
1979年 | 80篇 |
1978年 | 57篇 |
1977年 | 47篇 |
1976年 | 53篇 |
1975年 | 53篇 |
1973年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
James I. Geller MD Joseph G. Pressey MD Malcolm A. Smith MD Rachel A. Kudgus PhD Mariana Cajaiba MD Joel M. Reid PhD David Hall PhD Donald A. Barkauskas PhD Stephen D. Voss MD Steve Y. Cho MD Stacey L. Berg MD Jeffrey S. Dome MD PhD Elizabeth Fox MD Brenda J. Weigel MD 《Cancer》2020,126(24):5303-5310
3.
4.
Stacey A Thom Jeannette D Hoit Thomas J Hixon Alice E Smith 《The Cleft palate-craniofacial journal》2006,43(5):539-546
OBJECTIVE: To determine the age at which infants achieve velopharyngeal closure during vocalization. DESIGN: Longitudinal with repeated measures. SETTING: Laboratory. PARTICIPANTS: Six healthy infants were studied monthly from ages 2 to 6 months while they interacted with a parent and an investigator. MAIN OUTCOME MEASURES: The presence or absence of velopharyngeal closure, as determined by sensing ram pressure at the anterior nares. RESULTS: The velopharynx was open for windups, whimpers, and laughs, and it was closed for cries, screams, and raspberries, regardless of age. The frequency with which the velopharynx closed during syllable utterances increased significantly with age. CONCLUSIONS: Velopharyngeal closure for speech-like utterance increases with age, but is not complete and is still undergoing development at 6 months of age. Velopharyngeal closure during infancy may be influenced by pressure demands of the utterance; however, support for this speculation is stronger for other types of utterances than it is for speech-like utterances. The method used in this study holds promise for evaluating infants with suspected velopharyngeal impairment. 相似文献
5.
Katsuo Kamata Ayako Makino Noriyasu Kanie Shu-ichi Oda Takayuki Matsumoto Tsuneo Kobayashi Toyohiko Kikuchi Masato Nishimura Toshio Honda 《Journal of Smooth Muscle Research》2006,42(2-3):75-88
Anthocyanins, which are responsible for a variety of bright colors (including red, blue, and purple) in fruits, vegetables, and flowers, are consumed as dietary polyphenols. Anthocyanin-containing fruits are thought to decrease coronary heart disease and are used in anti-diabetic preparations. Diabetes is associated with a variety of cardiovascular complications that may be mediated by endothelial dysfunction, and so this study was designed mainly to characterize the influence of a synthesized anthocyanidin derivative (HK-008) over acetylcholine (ACh)-induced relaxation in mesenteric arterial beds isolated from rats. In a glucose-tolerance test in intact rats, HK-008 (30 mg/kg) reduced the glucose level as effectively as the same dose of glibenclamide. The aortic relaxation induced by pinacidil (an ATP-sensitive potassium channel opener) was greatly inhibited by glibenclamide (10 microM), and also significantly inhibited by HK-008 (10 microM). Interestingly, the ACh-induced relaxation in the perfused, preconstricted mesenteric arterial bed was significantly enhanced by HK-008 (10 microM), and this enhancement was significantly attenuated by indomethacin (10 microM). The ACh-induced mesenteric relaxation was impaired by an increase in oxidative stress, viz. superoxide-generating treatment [xanthine oxidase (XO; 0.1 U/ml) plus hypoxanthine (HX; 10 microM)]. However, this impairment was strongly suppressed by HK-008 (10 microM). These results suggest that HK-008 increases endothelium-induced relaxation by suppressing oxidative stress or modulating prostanoids signaling. This compound may therefore be useful against certain cardiovascular disorders. 相似文献
6.
Postpartum fatigue is a normal condition that most women experience. Breastfeeding is often associated in women's minds as contributing to the feeling of overall perceived fatigue, and many women indicate that they have ceased breastfeeding because of fatigue. However, the relationship between feeding choice and perceived fatigue has never been established. Two hundred and fifty-three women participated in a study examining whether perceived fatigue differed for bottle-feeding and breastfeeding women at 3 different times during the postpartum period (2-4 days, 6 weeks, and 12 weeks postpartum). Results showed no significant differences for these 2 groups, suggesting that perceived fatigue during the postpartum period is not dependent on feeding choice. Additional analyses examining other variables with a potential effect were nonsignificant. Because perceived physical fatigue does not appear to be dependent on feeding choice, women should be prepared for the feeling of perceived fatigue during the postpartum period while at the same time be reassured that feeding choice is not correlated. 相似文献
7.
Increase in Power through Multivariate Analyses 总被引:6,自引:0,他引:6
Power to detect genetic and environmental influences increases not only with sample size but also with the number of measurements through longitudinal and/or multivariate designs, if those measurements correlate with each other. Power simulations are presented for uni- through quadrivariate cases, with differing genetic and environmental parameters. Even though subject attrition is a problem for most longitudinal studies, the gain in power available may more than make up for this shortcoming in many situations. In terms of planning studies to examine genetic and environmental influences, power calculations should not only consider sample size but number of measurements on particular phenotypes and their intercorrelations. 相似文献
8.
Allergic Predisposition Among Infants with Bronchiolitis 总被引:1,自引:0,他引:1
Yoko Nagayama Nobukiyo Sakurai Toshiro Nakahara Masahiro Makuta Somei Kojima Shigeru Funabashi Akihito Honda 《The Journal of asthma》1987,24(1):9-17
Allergic predisposition among infants with bronchiolitis was examined. The number of infants with serum IgE exceeding mean +1 SD was 31/70 (44.3%). The rate of positive radioallergosorbent test (RAST) scores of 1 or more to mites, egg white, or milk was 31/71 (43.7%) and that of scores over 2 was 11/71 (15.5%). Eosinophils and/or mast cells were found in their nasal smears on several occasions. These results indicated that allergic predisposition may be observed among infants with bronchiolitis. 相似文献
9.
10.
A 67-year-old woman, who presented polyneuropathy, pleural effusion, ascites and sclerosing changes in the ribs, was admitted to our hospital on June 17, 1987. On admission, cerebrospinal examination showed a marked protein-cell dissociation and a delay in nerve conduction velocity. Bence-Jones protein was detected in urine, and the immunohistochemical study of biopsied bone marrow of the rib revealed lambda-chain positive plasmacytoma. Serum immunoelectrophoresis, however, showed no monoclonal gamma-globulinemia. From the findings described above, she was diagnosed as having Crow-Fukase syndrome associated with lambda-type light chain disease. Even with a therapy by prednisolone, platelet counts progressively declined to 10,000/ml3. Bone marrow aspiration showed normal number of megakaryocytes. Since platelet-associated IgG was increased to 452 ng/1.0 x 10(8) plt, a diagnosis of autoimmune thrombocytopenia was considered. Melphalan and cyclophosphamide to plasmacytoma resulted in a marked improvement of platelets. In addition, the level of platelet-associated IgG returned to normal range. Polyneuropathy, however, didn't respond to those therapies. It was suggested that both Crow-Fukase syndrome and thrombocytopenia were closely concerned with plasmacytoma but developed in a different manner. 相似文献