全文获取类型
收费全文 | 256500篇 |
免费 | 14786篇 |
国内免费 | 8628篇 |
专业分类
耳鼻咽喉 | 2765篇 |
儿科学 | 8326篇 |
妇产科学 | 2973篇 |
基础医学 | 16859篇 |
口腔科学 | 4244篇 |
临床医学 | 27778篇 |
内科学 | 41129篇 |
皮肤病学 | 3066篇 |
神经病学 | 11298篇 |
特种医学 | 12798篇 |
外国民族医学 | 24篇 |
外科学 | 33278篇 |
综合类 | 23735篇 |
现状与发展 | 25篇 |
预防医学 | 15964篇 |
眼科学 | 4504篇 |
药学 | 45145篇 |
90篇 | |
中国医学 | 14366篇 |
肿瘤学 | 11547篇 |
出版年
2023年 | 1947篇 |
2022年 | 8153篇 |
2021年 | 10333篇 |
2020年 | 5446篇 |
2019年 | 11309篇 |
2018年 | 5953篇 |
2017年 | 5432篇 |
2016年 | 7604篇 |
2015年 | 10512篇 |
2014年 | 19581篇 |
2013年 | 17220篇 |
2012年 | 21694篇 |
2011年 | 18848篇 |
2010年 | 16962篇 |
2009年 | 16558篇 |
2008年 | 15244篇 |
2007年 | 15721篇 |
2006年 | 13349篇 |
2005年 | 9015篇 |
2004年 | 4986篇 |
2003年 | 4335篇 |
2002年 | 3392篇 |
2001年 | 2684篇 |
2000年 | 2334篇 |
1999年 | 1510篇 |
1998年 | 1855篇 |
1997年 | 1686篇 |
1996年 | 1375篇 |
1995年 | 1378篇 |
1994年 | 1360篇 |
1993年 | 1004篇 |
1992年 | 1255篇 |
1991年 | 1105篇 |
1990年 | 1151篇 |
1989年 | 1110篇 |
1988年 | 1000篇 |
1987年 | 882篇 |
1986年 | 712篇 |
1985年 | 1665篇 |
1984年 | 1819篇 |
1983年 | 1325篇 |
1982年 | 1380篇 |
1981年 | 1348篇 |
1980年 | 1152篇 |
1979年 | 987篇 |
1978年 | 758篇 |
1977年 | 758篇 |
1976年 | 663篇 |
1974年 | 456篇 |
1973年 | 433篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
Saturated solubility and reaction rate constants for the decomposition of benzoyl peroxide in solution and suspension were determined for use in formulation development. The solvents studied included ethanol, propylene glycol, and cosolvent mixtures of PEG 400 and water. The solubility of benzoyl peroxide was inversely related to the solvent polarity, with greater solubility occurring with semipolar solvents. The stability of benzoyl peroxide in solution was dependent on the solvent, concentration of benzoyl peroxide, and temperature. The compound was least stable in PEG 400. Stability was improved when water was added to PEG 400. Similar solvent effects were observed in suspension. In benzoyl peroxide suspensions of PEG 400 and PEG 400/water blends, benzoyl peroxide stability was dependent on solubility, with improved stability occurring in blends where the benzoyl peroxide was least soluble. Thus, solution formulations of benzoyl peroxide in pharmaceutically acceptable solvents are unlikely to show good stability; however, suspension formulations should be reasonably stable if the vehicle is selected to provide low benzoyl peroxide solubility. 相似文献
972.
Prognostic factors in myeloma are not only important for allowing comparisons to be made between therapeutic protocols but they also provide us with an insight into the pathophysiology of the disease and important mechanisms which result in disease progression. Prognostic factors in myeloma relate to the inherent proliferative capacity of the malignant clone, tumor bulk, renal function and other factors which reflect tumor host and host tumor interactions. The highly significant effect of the labelling index (LI) suggests that the clonogenic cell is ontologically very close to the malignant plasma cell on which the labelling index is derived. The explanation for the important role of the β2-microglobulin (β2M) level over and above its reflection of renal function is as yet unclear. 相似文献
973.
氧氟沙星滴耳剂的高效液相色谱分析和稳定性研究 总被引:6,自引:2,他引:4
本文采用反相高效液相色谱法考察了氧氟沙星滴耳剂的稳定性。该法简便、迅速、专属性强、精密度好,制剂回收率为99.97%。经光照、高温、低温和加速试验,结果表明:本制剂对冷和热稳定,对光不稳定。建议氧氟沙星滴耳剂暂定有效期2年,使用中应注意避光保存。 相似文献
974.
The mortality of neonates with oesophageal atresia in the Third World remains high because of delays in presentation and diagnosis. Lack of appropriate intensive care facilities is a further contributing factor. Caudothoracic epidural anaesthesia was used during surgical repair of oesophageal atresia in 35 patients in an attempt to minimise the need for post-operative ventionally support. This group was compared with 36 patients whose surgery was performed under general anaesthesia. The age at the time of referral, sex ratio, and weight were comparable in both groups. Using the Waterson classification, a greater number of poorer prognostic patients were seen in the epidural group (P <0.02). In all Waterson risk categories fewer patients required ventionally support post-operatively, which was statistically significant (P <0.01) when all categories were combined. We are encouraged by our results and believe this technique has a rôle in the management of neonates undergoing major surgery, both where neonatal intensive care exist or is deficient as in many parts of the Third World. 相似文献
975.
Is the effect of acute hyperglycaemia on interdigestive antroduodenal motility and small-bowel transit mediated by insulin? 总被引:2,自引:0,他引:2
H. A. J. GIELKENS M. VERKIJK M. FRÖLICH C. B. H. W. LAMERS & A. A. M. MASCLEE 《European journal of clinical investigation》1997,27(8):703-710
Acute hyperglycaemia inhibits antroduodenal motility. In non-diabetic subjects this inhibitory effect may result from reactive endogenous hyperinsulinaemia. Therefore, we investigated the effects of hyperinsulinaemia during both hyperglycaemia and euglycaemia on interdigestive antroduodenal motility (perfusion manometry) and duodenocaecal transit time (DCTT; lactulose breath-H2 test). Six healthy volunteers (age 20–26 years) were studied for 240 min on three separate occasions in random order during: (a) i.v. saline (control); (b) acute hyperglycaemic hyperinsulinaemia (HG) with plasma glucose at 15 mmol L?1; and (c) euglycaemic hyperinsulinaemia (HI) with plasma insulin at 80 mU L?1 and glucose at 4–5 mmol L?1. Results: DCTT was significantly (P < 0.05) prolonged during HG (158 ± 23 min) compared with control (95 ± 25 min), whereas HI had no effect (100 ± 17 min). Mean duration of complete migrating motor complex (MMC) cycles was significantly (P < 0.05) reduced during HG (63 ± 9 min) compared with control (103 ± 15 min) and HI (105 ± 16 min), which resulted from a significantly (P < 0.05) shorter duration of phase II. Antral motility was significantly (P < 0.05) reduced during both HI (20 ± 8 contractions 240 min?1) and HG (9 ± 5) compared with control (43 ± 7). It is concluded that in healthy subjects hyperglycaemia prolongs DCTT, increases duodenal MMC cycle frequency and inhibits antral motility. Hyperinsulinaemia reduces antral motor activity but has no effect on interdigestive duodenal motility or DCTT. Thus, other factors, apart from insulin, mediate the inhibitory effect of hyperglycaemia on interdigestive intestinal motility and transit. 相似文献
976.
977.
ATP片剂的UV—HPLC测定 总被引:2,自引:0,他引:2
采用UV-HPLC法测定ATP片剂的含量,较地方标准收载的方法方便易行,重现性好。测定的回收率为100.8±1.5%。 相似文献
978.
采用HPLC测定健康志愿者血浆中头孢克洛的浓度。方法简便快速,结果准确。平均回收率为102.18±4.01%,日间及日内RSD均小于6%。血药浓度-时间曲线符合一室模型。 相似文献
979.
Daniel P. Venter 《European journal of pharmacology》1997,320(2-3):223-231
A new method for estimating relative efficacies and relative intrinsic efficacies of agonists is described. Relative efficacy is estimated by employing a newly defined efficacy related parameter (eES) and it may be estimated without prior knowledge of efficacy values or the value of the equilibrium dissociation constants, KA, of agonist-receptor complexes. The parameter eES is directly related to efficacy (e) and is defined as the ratio of maximal stimulus to maximal effect of an agonist. The value of eES indicates whether or not spare receptors are present for a particular agonist–effector system. The eES values of agonists are estimated by utilizing submaximal concentration–effect curves determined with fixed agonist-competitive antagonist concentration combinations and choosing a suitable reference (height of an agonistic concentration–effect curve) to which the height of the stimulus concentration–effect curves of the agonist may be compared. In addition to eES, other new agonist–effector parameters, namely SEm/Sm and φmin, were also defined. 相似文献
980.
高效液相色谱法测定芩连葛根片中葛根素的含量 总被引:3,自引:0,他引:3
采用反相高效液相色谱法测定芩连葛根片中葛根素的含量,以ODSC18为分析柱,柱温为室温,流动相为甲醇-0.3%醋酸液梯度淋洗,检测波长为280nm。在此色谱条件下,葛根素得到较好的分离,测定方法简便、准确、灵敏度高。 相似文献