全文获取类型
收费全文 | 28499篇 |
免费 | 1524篇 |
国内免费 | 133篇 |
专业分类
耳鼻咽喉 | 532篇 |
儿科学 | 1610篇 |
妇产科学 | 818篇 |
基础医学 | 3186篇 |
口腔科学 | 1238篇 |
临床医学 | 2614篇 |
内科学 | 5193篇 |
皮肤病学 | 774篇 |
神经病学 | 2616篇 |
特种医学 | 1141篇 |
外国民族医学 | 4篇 |
外科学 | 4894篇 |
综合类 | 376篇 |
一般理论 | 24篇 |
预防医学 | 1636篇 |
眼科学 | 649篇 |
药学 | 1551篇 |
4篇 | |
中国医学 | 180篇 |
肿瘤学 | 1116篇 |
出版年
2023年 | 282篇 |
2022年 | 331篇 |
2021年 | 634篇 |
2020年 | 458篇 |
2019年 | 531篇 |
2018年 | 825篇 |
2017年 | 654篇 |
2016年 | 714篇 |
2015年 | 796篇 |
2014年 | 1046篇 |
2013年 | 1369篇 |
2012年 | 1854篇 |
2011年 | 2013篇 |
2010年 | 1093篇 |
2009年 | 891篇 |
2008年 | 1505篇 |
2007年 | 1743篇 |
2006年 | 1603篇 |
2005年 | 1752篇 |
2004年 | 1666篇 |
2003年 | 1538篇 |
2002年 | 1378篇 |
2001年 | 758篇 |
2000年 | 826篇 |
1999年 | 592篇 |
1998年 | 239篇 |
1997年 | 193篇 |
1996年 | 146篇 |
1995年 | 128篇 |
1994年 | 104篇 |
1993年 | 96篇 |
1992年 | 219篇 |
1991年 | 183篇 |
1990年 | 172篇 |
1989年 | 133篇 |
1988年 | 153篇 |
1987年 | 131篇 |
1986年 | 120篇 |
1985年 | 108篇 |
1984年 | 101篇 |
1983年 | 72篇 |
1982年 | 62篇 |
1979年 | 88篇 |
1978年 | 72篇 |
1975年 | 49篇 |
1974年 | 66篇 |
1973年 | 75篇 |
1972年 | 49篇 |
1971年 | 59篇 |
1970年 | 56篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
A combination of psyllium fiber with nutrients in a commercially available wafer (Fiberall-Ciba Consumer Pharmaceutical) was evaluated for its effectiveness in reducing food intake and appetite. Each of 15 nonobese healthy women received no wafers and four different amounts (39, 104, 169, and 234 kcal) of the fiber wafer with water, in a ratio of 13 kcal (and 0.565 g psyllium) wafer per 41.67 g water, 30 minutes prior to a test meal of macaroni and beef, on nonconsecutive days. Intake of the test meal and hunger ratings were both significantly reduced after intake of the two largest wafer amounts (169 and 234 kcal, respectively), in comparison with the two smaller amounts and none at all. The reduction produced by the largest amount compared to none at all was 122 kcal (about half the energy of the amount given). There were no significant differences in intake and hunger ratings among the two smaller amounts and none at all. Thus the threshold for intake reduction by this product with water lies between 104 and 169 kcal. Methodologically, this work underscores the importance of testing the satiating effects of foods at multiple levels before conclusions are drawn about their satiating effectiveness, and suggests that the threshold for significant reduction should be considered as a measure of the product's satiating effectiveness. The relative contributions of the nutrients, the fiber, and the water to the satiating effect still need to be determined. 相似文献
72.
ADP plays a key role in thrombogenesis in rats 总被引:3,自引:0,他引:3
J P Maffrand A Bernat D Delebassée G Defreyn J P Cazenave J L Gordon 《Thrombosis and haemostasis》1988,59(2):225-230
The relative importance of ADP, arachidonic acid metabolites and serotonin as thrombogenic factors was evaluated in rats by comparing, after oral administration, the effects of two inhibitors of ADP-induced platelet aggregation (ticlopidine and PCR 4099), three cyclo-oxygenase inhibitors (aspirin, triflusal and indobufen) and a selective serotonin 5HT2 receptor antagonist (ketanserin) on platelet aggregation, in four platelet-dependent thrombosis models and on bleeding time. Platelet aggregation induced by ADP and collagen was completely inhibited by ticlopidine and PCR 4099 whereas only the collagen aggregation was reduced by the cyclo-oxygenase inhibitors. Ketanserin or a depletion of platelet serotonin by reserpine did not affect platelet aggregation. Ticlopidine and PCR 4099 greatly prolonged rat tail transection bleeding time. This is probably related to their known ability to inhibit ADP-mediated platelet aggregation. In contrast, the cyclooxygenase inhibitors did not affect bleeding time at all. Reserpine and ketanserin prolonged bleeding time by interfering with the action of serotonin on the vascular wall. Ticlopidine and PCR 4099 were very potent antithrombotics in all the models. Aspirin, only at a high dose, inhibited poorly thrombus formation on a silk thread in an arterio-venous shunt, suggesting that the inhibition of cyclo-oxygenase was not responsible. Triflusal was inactive in all models while indobufen slightly reduced thrombus formation in the silk thread and metallic coil models. Ketanserin and reserpine reduced thrombus only in the metallic coil model. Thrombus formation was greatly reduced in fawn-hooded rats, which lack ADP in their platelet dense granules because of a genetic storage pool deficiency.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
73.
Emmanuelle Ponty Michel Carton Georges Soula Gillcs Favre Rachid Benaniba Andre Boneu Henriette Lucot 《International journal of cancer. Journal international du cancer》1993,54(3):411-417
Since there is strong evidence of a preferential LDL accumulation in tumor cells, LDL might be of interest for tumor imaging. We have tested the ability of 99mTc-LDL in tumor imaging with B16-melanoma-bearing mice as a model for further applications in human studies. The LDL fixation rate was higher with 99mTc-labeled LDL than with 125I labeled LDL. Since technetium-99m remains trapped in the cells, 99mTc-LDL is a well-adapted radioligand because of information given by this radiotracer on the receptor metabolism. We observed that, at early growth stages, the tumor took up the LDL at a maximal rate, suggesting differences in cholesterol metabolism as a function of tumor growth. Accumulation of label in the tumor area was perfectly observable in tumor-bearing mice on scintigraphic images. Computerized quantification of the regions of interest (as well as biodistribution studies including killing of the animals) showed a 1.81 -fold increase in uptake by the tumor as compared to the liver and a 28-fold increase as compared with corresponding normal tissue (muscle of the left leg) at day 8 of tumor growth. These data give strong support to the value of this non-invasive method in visualizing and quantifying the tissue LDL uptake in vivo, including the precise information provided by nuclear scintigraphy on the distribution of the radiolabeled LDL in the different tissues. 99mTc-LDL could be an efficient tool for further diagnostic or therapeutic exploration in cancer patients. 相似文献
74.
N. J. Krag J. Nrregaard J. K. Larsen B. Danneskiold-Samse 《Acta psychiatrica Scandinavica》1994,89(6):370-375
The objective of the study was to evaluate the presence of psychopathology in fibromyalgia patients compared with a control group of other rheumatologic patients with pain. Forty-nine fibromyalgia patients and 33 control patients were interviewed blinded, using standardized psychometric scales. Pain was scored on a visual analogue scale. Fibromyalgia patients scored significantly higher than the controls on the Bech-Rafaelsen Melancholia Scale, the Atypical Depression Scale and the Hamilton Anxiety Rating Scale. On the Newcastle Depression Scale there was no difference. In both groups a correlation was found between pain score and psychometric scoring. The fibromyalgia patients scored significantly higher on pain than the controls. After correcting for this difference, the fibromyalgia patients still scored higher on anxiety and depression. 相似文献
75.
Buket Pene Nilgn Atakan Sevin Akkaya Aytac Gkz 《Journal of the European Academy of Dermatology and Venereology》1994,3(4):484-489
In recent years, research on the aetiology of psoriasis has focused on immune aetiopathogenesis. However, in the last few years, research on the immunoloogical changes in psoriasis has failed to mention the lymphatics. Also, studies emphasizing the importance of the dermal lymphatics have neglected the lymphatic changes seen in psoriasis. Therefore, we decided to put this matter back on the agenda. Skin biopsies from 20 patients with psoriasis vulgaris were examined lymphatically by light microscopy using the orcein stain. We found a considerable increase in both number and dilatation in the lymphatics of psoriatic plaques, compared with both the clinically uninvolved skin of the psoriatic patients and also the skin of the control group. 相似文献
76.
S Jacobsen B Danneskiold-Sams?e 《Archives of physical medicine and rehabilitation》1992,73(2):170-173
The objective of the study was to quantify the voluntary dynamic muscular endurance (DME) in patients with primary fibromyalgia (PF) since easy fatigability of muscles is one of the major symptoms in this syndrome. Consecutive outpatients referred to a rheumatology clinic specializing in PF were investigated. Thirty-six patients with PF were compared with 18 patients with chronic myofascial pain (CMP) syndrome. Subjects were matched according to gender, age, height, weight, peak torque, and contractional work. The DME was defined as the number of repeated knee extensions necessary for the contractional work in two successive knee extensions to be equal to or below 70% of the initial value measured with an isokinetic dynamometer. A significantly lower DME was found in the PF group than in the CMP group: 11 (7-13) and 18 (11-25), respectively (median and quartiles), p less than .005. Patients with PF have a low voluntary muscular endurance compared to CMP patients. 相似文献
77.
L A D'Albuquerque A de Oliveira e Silva T Genzini M P de Miranda F Roldan-Molina 《Arquivos de gastroenterologia》1991,28(4):124-131
In the period of January 1978 to October 1988, 32 Le Veen shunts (LVS) were implanted in 20 patients, out of which 16 were alcoholic cirrhotics and 4 postnecrotic cirrhotics. In the present study, we correlated preoperative laboratory data of these patients with their postoperative evolution, comparing the clinical results of patients who survived more than 30 days (13 patients = 65%) with the results of those who died within the same period (7 patients = 35%). For that matter, 14 laboratory tests were performed in order to measure the serum levels of hematocrit, hemoglobin, urea, creatinine, sodium, potassium, bilirubin, albumin, AST, ALT, alkaline phosphatase, fibrinogen, gamma GT and prothrombin activity. After statistical analysis, we observed that 6 of the 14 tests performed could be considered of prognostic value in the following decreasing order of importance: fibrinogen, alkaline phosphatase, prothrombin activity, urea, gamma GT and bilirubin. We observed that all the 7 patients who died prematurely presented 3 or more of these levels altered, when compared with standard values. Based on these data, we concluded that serum levels of fibrinogen, alkaline phosphatase, urea, gamma GT, bilirubin and activity of prothrombin proved to be important factors in determining the prognosis of immediate survival in cirrhotic patients who underwent LVS implantation. We also concluded that when 3 or more of these factors are altered, the implant of LVS is contraindicated, whatever clinical criteria for indication and contraindication were taken into account. 相似文献
78.
Pelvic floor muscle training with biofeedback and bladder training in elderly women: a feasibility study. 总被引:1,自引:0,他引:1
Louise Perrin Sharon Wood Dauphinée Jacques Corcos James A Hanley George A Kuchel 《Journal of wound, ostomy, and continence nursing》2005,32(3):186-199
OBJECTIVE: It is generally assumed that interventions used to treat urinary incontinence (UI) in young women could simply be applied to older competent and motivated women, but these assumptions have not been formally tested. The purpose of this study was to determine the feasibility of using physical therapies to treat UI in older women. DESIGN: Twelve-week time series. SETTINGS AND SUBJECTS: We recruited women older than 75 years with UI from an outpatient urology clinic and a waiting list for incontinence surgery. METHODS: After a baseline evaluation, the women collected data on their incontinence symptoms and bladder habits for 3 weeks using the 72-hour voiding diary and the 24-hour pad test. They then received 6 physical therapy treatments consisting of a combination of bladder training and pelvic floor muscle training assisted with biofeedback for 6 weeks. This was followed by another 3-week period of data collection and a final evaluation. RESULTS: Ten women participated in the study; 7 completed it. They were all comfortable with the treatment. They complied with the study demands in terms of attendance at treatment session (100%), data collection (96%), and completion of exercises at home (82%). The authors observed a decrease in the number of incontinent and urgency episodes. CONCLUSION: This preliminary study demonstrates that some women older than 75 years are good candidates to undertake physical therapies for UI and follow study demands. Random controlled studies that include this population will provide evidence regarding the effectiveness of these therapies. 相似文献
79.
Dr. Bektaş Açikgöz Mehmet Turgut Osman Ekin Özcan Tunçalp Özgen Beyhan Demirhan Şevket Ruacan 《Lasers in medical science》1992,7(1-4):49-53
In this study we have investigated the negative influence of CO2 and Nd-YAG laser irradiation on rapid cranial regeneration and whether it has any use in certain types of craniosynostosis.
Twenty-two newborn rats were used in the study. Both CO2 and Nd-YAG laser irradiation, which was applied to free bony edges after, suturectomies, resulted in a significant decrease
in skull regeneration. Histopathological examinations revealed severe degeneration caused by both types of laser energies. 相似文献
80.
P Wattiau B Bernier P Deslée T Michiels G R Cornelis 《Proceedings of the National Academy of Sciences of the United States of America》1994,91(22):10493-10497
Pathogenic yersiniae secrete anti-host proteins called Yops, by a recently discovered Sec-independent pathway. The Yops do not have a classical signal peptide at their N terminus and they are not processed during membrane translocation. The secretion domain is nevertheless contained in their N-terminal part but these domains do not resemble each other in the different Yops. We have previously shown that YopE secretion requires SycE, a 15-kDa acidic protein acting as a specific cytosolic chaperone. Here we show that the gene downstream from yopH encodes a 16-kDa acidic protein that binds to hybrid proteins made of the N-terminal part of YopH and either the bacterial alkaline phosphatase or the cholera toxin B subunit. Loss of this protein by mutagenesis led to accumulation of YopH in the cytoplasm and to a severe and selective reduction of YopH secretion. This protein thus behaves like the counterpart of SycE and we called it SycH. We also engineered a mutation in lcrH, the gene upstream from yopB and yopD, known to encode a 19-kDa acidic protein. Although this mutation was nonpolar, the mutant no longer secreted YopB and YopD. The product of lcrH could be immunoprecipitated together with cytoplasmic YopD. lcrH therefore seems to encode a YopD-specific chaperone, which we called SycD. Determination of the dependence of YopB on SycD requires further investigation. SycE, SycH, and SycD appear to be members of a new family of cytosolic chaperones required for Yop secretion. 相似文献