全文获取类型
收费全文 | 15294篇 |
免费 | 1102篇 |
国内免费 | 367篇 |
专业分类
耳鼻咽喉 | 52篇 |
儿科学 | 207篇 |
妇产科学 | 165篇 |
基础医学 | 1698篇 |
口腔科学 | 140篇 |
临床医学 | 623篇 |
内科学 | 2252篇 |
皮肤病学 | 245篇 |
神经病学 | 861篇 |
特种医学 | 311篇 |
外国民族医学 | 1篇 |
外科学 | 1025篇 |
综合类 | 2063篇 |
预防医学 | 717篇 |
眼科学 | 160篇 |
药学 | 2373篇 |
中国医学 | 3046篇 |
肿瘤学 | 824篇 |
出版年
2024年 | 53篇 |
2023年 | 179篇 |
2022年 | 365篇 |
2021年 | 413篇 |
2020年 | 336篇 |
2019年 | 684篇 |
2018年 | 675篇 |
2017年 | 490篇 |
2016年 | 354篇 |
2015年 | 397篇 |
2014年 | 636篇 |
2013年 | 803篇 |
2012年 | 769篇 |
2011年 | 870篇 |
2010年 | 666篇 |
2009年 | 649篇 |
2008年 | 652篇 |
2007年 | 721篇 |
2006年 | 625篇 |
2005年 | 470篇 |
2004年 | 442篇 |
2003年 | 464篇 |
2002年 | 403篇 |
2001年 | 431篇 |
2000年 | 287篇 |
1999年 | 246篇 |
1998年 | 169篇 |
1997年 | 174篇 |
1996年 | 102篇 |
1995年 | 101篇 |
1994年 | 85篇 |
1993年 | 74篇 |
1992年 | 63篇 |
1991年 | 63篇 |
1990年 | 60篇 |
1989年 | 53篇 |
1987年 | 50篇 |
1985年 | 271篇 |
1984年 | 389篇 |
1983年 | 265篇 |
1982年 | 268篇 |
1981年 | 244篇 |
1980年 | 204篇 |
1979年 | 219篇 |
1978年 | 171篇 |
1977年 | 97篇 |
1976年 | 165篇 |
1975年 | 135篇 |
1974年 | 90篇 |
1973年 | 82篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
傣药芽拉勐龙(Cassia alata L.)是傣医药史籍中有记载且傣医临床中最常用的药材之一,它在泰国应用同样广泛多见,是已开发应用得较为成熟的药用植物,相关研究也较多。在西双版纳,民间傣医常在夏秋季节采收芽拉勐龙,认为这期间的芽拉勐龙叶才有更好的疗效,但尚未发现相关的理论依据支持这种说法,因此笔者在2008年7月到11月间,采集每个月份的芽拉勐龙叶进行其乙醇提取物的含量测定,以找到它的最佳采集使用期。通过其采收季节中有效成分含量的比较结果显示,有效成分最高的时间是11月份,故在采收芽拉勐龙时,应掌握时机,在11月份采收为佳。 相似文献
12.
Robert M. Levy Roman Saikovsky Evgeniya Shmidt Alexander Khokhlov Bruce P. Burnett 《Nutrition Research》2009
Flavocoxid (Limbrel), a proprietary mixture of flavonoid molecules (baicalin and catechin), was tested against a traditional nonsteroidal anti-inflammatory drug, naproxen, for the management of the signs and symptoms of moderate osteoarthritis (OA) in humans. Discomfort and global disease activity were used as the primary end points, and safety assessments were also taken for both treatments as a secondary endpoint. In this double-blind study, 103 subjects were randomly assigned to receive either flavocoxid [500 mg twice daily (BID)] or naproxen (500 mg BID) in a 1-month onset of action trial. Outcome measures included the short Western Ontario and McMaster University Osteoarthritis Index, subject Visual Analogue Scale for discomfort and global response, and investigator Visual Analogue Scale for global response and fecal occult blood. Both flavocoxid and naproxen showed significant reduction in the signs and symptoms of knee OA (P ≤ .001). There were no statistically detectable differences between the flavocoxid and naproxen groups with respect to any of the outcome variables. Similarly, there were no statistically detectable differences between the groups with respect to any adverse event, although there was a trend toward a higher incidence of edema and nonspecific musculoskeletal discomfort in the naproxen group. In this short-term pilot study, flavocoxid was as effective as naproxen in controlling the signs and symptoms of OA of the knee and would present a safe and effective option for those individuals on traditional nonsteroidal anti-inflammatory drugs or cyclooxygenase-2 inhibitors. A low incidence of adverse events was reported for both groups. 相似文献
13.
Marc Ziegler Alexandre Castro-Caldas Susanna Del Signore Olivier Rascol 《Movement disorders》2003,18(4):418-425
Piribedil is a non-ergot D2/D3 agonist with a significant antagonist action on alpha2A and alpha2C adrenergic receptor subtypes. This double-blind placebo-controlled study was undertaken to confirm the efficacy of 150 mg/day piribedil po in improving motor symptoms of idiopathic Parkinson's disease (PD) in nonfluctuating patients insufficiently controlled by a stable daily dose of levodopa (L-dopa). Efficacy was assessed using the Unified Parkinson's Disease Rating Scale (UPDRS) III score as primary criterion over 4 months. A second comparison was planned at 6 months, after possible adjustment of L-dopa. At 4 months, the rate of response, defined as a 30% decrease from baseline on UPDRS III score, was significantly greater with piribedil compared with placebo (56.4% vs. 37.7%; P = 0.040). At 6 months, the better efficacy of piribedil was maintained (61.8% of responders vs. 39.6% on placebo; P = 0.020). The difference between groups on UPDRS III change from baseline reached statistical significance only at 6 months: -10.0 points in the piribedil group vs. -6.7 points in the placebo group (P = 0.037). Secondary end-points were not significantly different. The most frequently reported adverse events were gastrointestinal symptoms (27 of 61 patients in the piribedil group vs. 13 of 54 patients in the placebo group). In conclusion, a 6-month oral administration of 150 mg/day piribedil in combination with L-dopa is well tolerated, except for minor gastrointestinal symptoms at the beginning of the treatment and significantly improves motor symptoms compared with placebo in PD nonfluctuating patients. 相似文献
14.
本文采用RP-HPLC方法对紫苏油及其习用品白苏油、野苏油甘油酯进行了定性定量分析。利用HPLC分析油脂也为中药材真伪鉴别提供了一条有效途径。 相似文献
15.
D. Nolte S. Pickelmann S. Swaid F. H?lzle und K.-D. Wolff 《Mund-, Kiefer- und Gesichtschirurgie》2003,7(1):31-35
Zusammenfassung
Fragestellung. Ziel der vorliegenden Untersuchung war, die Effekte der Sauerstoff tragenden freien H?moglobinl?sung (Diaspirin-crosslinked-H?moglobin,
DCLHb) auf die kapillare Perfusion sowie die Oxygenation im quergestreiften Hautmuskelgewebe nach kritischer Isch?miezeit
und nachfolgender Reperfusion zu analysieren.
Material und Methode. Die kapillare Gewebeperfusion wurde anhand der funktionellen Kapillardichte im Hautmuskel des syrischen Goldhamsters quantitativ
vor der Induktion einer 4-stündigen Isch?mie sowie nach 0,5 h, 2 h und 24 h Reperfusion mittels intravitaler Fluoreszenzmikroskopie
erfasst (n=8 pro Versuchsgruppe). In separaten Tieren wurde nach demselben Versuchsansatz mit der Mehrdrahtoberfl?chenelektrode (MDO,
Eschweiler, Kiel) die Gewebeoxygenation gemessen (n=8 pro Versuchsgruppe). Die Tiere der Testgruppe (n=8) erhielten 15 min vor der Reperfusion eine Kurzinfusion von 5 ml/kg KG DCLHb (Diaspirin-crosslinked-H?moglobin, 10 g/dl,
Baxter, IL, USA). Die Kontrolltiere (n=8) erhielten ?quivalente Dosen einer isotonen Kochsalzl?sung (Braun, Melsungen).
Ergebnisse. Die funktionelle Kapillardichte als Ma? für die L?nge von erythrozytenperfundierten Kapillaren pro Beobachtungsfeld war bei
den Kontrolltieren in der Reperfusionsphase dramatisch vermindert, w?hrend bei den mit DCLHb behandelten Tieren signifikant
h?here Werte nachweisbar waren (p<0,05). Diese Beobachtung spiegelte sich in einer vollst?ndigen Erholung des Gewebe-pO2 bei den Behandlungstieren wider, was in Kontrolltieren nicht erreicht wurde.
Schlussfolgerungen. Die Ergebnisse dieser Studie zeigen, dass die Sauerstoff tragende L?sung DCLHb nach kritischer Isch?mie und Reperfusion die
nutritive Perfusion und Gewebeoxygenation gegenüber kristalloiden L?sungen verbessert. Die Anwendung derartiger L?sungen scheint
unter den klinischen Bedingungen einer kritischen Isch?mie daher als viel versprechender adjuvanter therapeutischer Ansatz.
Electronic Publication 相似文献
16.
余甘子是一种具有较高的食用和药用价值的野生植物资源,风味独特,含有丰富的类SOD活性物质和其他多种具有生物活性的物质,具有清除自由基、抗肿瘤、抗衰老等保健作用。作者提出了余甘予保健口服液的生产工艺流程及配方,并采用改良的Marklund方法测定了类SOD的活力,结果较为满意。 相似文献
17.
目的 从福参Angelica morii提取分离活性成分。方法 采用乙醇提取,溶剂萃取,大孔树脂、聚酰胺、硅胶柱层析,LH-20、重结晶等纯化,对福参饮片进行系统提取分离;运用波谱学方法及理化常数对照进行结构鉴定。结果 从正丁醇和水部分分离到6个苷类化合物,分别为升麻索苷(prim-O-glucosylcimifugin,Ⅰ)、紫花前胡苷(marmesinin,Ⅱ)、芹菜素7-O-β-D-葡萄糖苷(apigenin 7-O0-β-D-glucoside,Ⅲ)、木犀草素7-O-β-D-葡萄糖苷(1ute—olin 7-O-β-D-glucoside,Ⅳ),umbeliferone 7-apiosylglucoside(V)和胡萝卜苷(daucosterol,Ⅵ)。结论 6个化合物均为首次该植物中分得;化合物Ⅲ首次从当归属中分得。 相似文献
18.
目的 大量富集三裂叶蟛蜞菊倍半萜内酯A,B(WTA,WTB)。方法 采用气相色谱法测定WTA和WTB,并以WTA和WTB的含量、洗脱率、精制度为考察指标,研究D101大孔树脂吸附WTA和WTB的工艺条件及参数。结果 通过大孔树脂吸附后,WTA和WTB的洗脱率达90%,50%乙醇洗脱部分中WTA和WTB的含量为总固物的4.01%~4.09%。结论 可以采用大孔树脂富集WTA和WTB。 相似文献
19.
Monocyte adhesion molecule expression in interstitial inflammation in patients with renal failure. 总被引:2,自引:0,他引:2
Elham Dadfar Joachim Lundahl Stefan H Jacobson 《Nephrology, dialysis, transplantation》2004,19(3):614-622
BACKGROUND: Patients with renal failure have an increased susceptibility to infections. We therefore studied the recruitment of monocytes and their expression of adhesion molecules CD11b and CD62L at the site of interstitial inflammation in patients with renal failure. Furthermore, we studied if the capacity of monocytes to up-regulate CD11b in interstitial inflammation was determined by the interstitial concentration of chemotactic factors. METHODS: Three intensities of interstitial inflammation (0, intermediate and intense) were established in skin blister chambers. Leukocyte count, CD11b/CD62L expression, monocyte chemotactic protein-1 (MCP-1) and blister activity in terms of CD11b mobilization were determined. RESULTS: The CD62L expression on monocytes was lower in the peripheral circulation in patients with renal failure compared with healthy subjects (P<0.005 and P<0.001). At the site of interstitial inflammation patients had a higher expression of CD62L (intermediate, P<0.05; intense, P<0.005). Furthermore, monocytes from patients had an impaired capacity to mobilize CD11b both in the peripheral circulation (P<0.005) and at the intermediate and intense sites of interstitial inflammation (P<0.005 and P<0.001, respectively) compared with cells collected from healthy subjects. We incubated monocytes in blister exudates, in order to explore whether this phenomenon is caused by cellular factors and/or to the interstitial concentration of chemotactic mediators. The expression of CD11b on monocytes from healthy blood donors incubated in blister exudates from either patients or healthy subjects in vitro was similar. The interstitial concentration of MCP-1 at the site of intermediate inflammation was significantly lower in patients with renal failure compared with the corresponding blister exudate collected from healthy subjects (P<0.05), but no differences were observed at the site of intense inflammation. Furthermore, neutralizing the action of MCP-1 in blister exudates with monoclonal antibodies did not have any impact on monocyte CD11b expression following incubation in blister exudates. CONCLUSION: These studies indicate that the impaired capacity of monocytes to mobilize CD11b at the site of inflammation in patients with renal failure is more dependent on constitutive cellular factors than the concentration of CD11b mobilizing factors in the interstitium. 相似文献
20.
利用主客体分子包结现象选择分离蛇床子有效成分的方法 总被引:2,自引:0,他引:2
利用1,1,6-四苯基-2,4-已二炔-1,6-二醇(I)的包结能力,可简单而迅速地从蛇床子中选择分离出有效成分欧前胡素(2)和花椒毒素(3),收率分别为0.054%(2)和0.002%(3)。本文用UV,IR,1HNMR和13CNMR验证了2和3的化学结构,并用HPLC检验了2和3的纯度。X-射线衍射晶体结构分析表明主体分子I与组分2靠氢键形成包结物,它们的摩尔比为1:2,氢键长为2.8612A。包结物晶体属单斜晶系,空间群为已P21/C,晶胞参数:a=15.468(5)A,b=8.595(3)A,c=18.663(7)A,β=93.64(5)°,Z=4和R=0.088。 相似文献