全文获取类型
收费全文 | 1497367篇 |
免费 | 112346篇 |
国内免费 | 3020篇 |
专业分类
耳鼻咽喉 | 21282篇 |
儿科学 | 46047篇 |
妇产科学 | 40697篇 |
基础医学 | 224042篇 |
口腔科学 | 43692篇 |
临床医学 | 133148篇 |
内科学 | 282977篇 |
皮肤病学 | 31697篇 |
神经病学 | 113889篇 |
特种医学 | 58188篇 |
外国民族医学 | 243篇 |
外科学 | 229530篇 |
综合类 | 37689篇 |
现状与发展 | 3篇 |
一般理论 | 408篇 |
预防医学 | 113460篇 |
眼科学 | 35610篇 |
药学 | 113660篇 |
3篇 | |
中国医学 | 3788篇 |
肿瘤学 | 82680篇 |
出版年
2018年 | 14436篇 |
2016年 | 12685篇 |
2015年 | 14491篇 |
2014年 | 20283篇 |
2013年 | 30675篇 |
2012年 | 41005篇 |
2011年 | 43163篇 |
2010年 | 25420篇 |
2009年 | 23894篇 |
2008年 | 40562篇 |
2007年 | 44102篇 |
2006年 | 44239篇 |
2005年 | 42571篇 |
2004年 | 41754篇 |
2003年 | 39998篇 |
2002年 | 38655篇 |
2001年 | 67689篇 |
2000年 | 69033篇 |
1999年 | 57761篇 |
1998年 | 16328篇 |
1997年 | 14494篇 |
1996年 | 14626篇 |
1995年 | 13861篇 |
1994年 | 13104篇 |
1992年 | 47143篇 |
1991年 | 46500篇 |
1990年 | 45581篇 |
1989年 | 44512篇 |
1988年 | 41173篇 |
1987年 | 40183篇 |
1986年 | 38256篇 |
1985年 | 36662篇 |
1984年 | 27767篇 |
1983年 | 23682篇 |
1982年 | 14143篇 |
1981年 | 12866篇 |
1980年 | 12198篇 |
1979年 | 27052篇 |
1978年 | 19398篇 |
1977年 | 16397篇 |
1976年 | 15355篇 |
1975年 | 16753篇 |
1974年 | 20362篇 |
1973年 | 19468篇 |
1972年 | 18453篇 |
1971年 | 17165篇 |
1970年 | 16434篇 |
1969年 | 15657篇 |
1968年 | 14226篇 |
1967年 | 12997篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
A Sharma H L Goh N Asokananthan A Bakker G A Stewart H W Mitchell 《The European respiratory journal》2006,27(1):20-28
Mucosal trypsin, a protease-activated receptor (PAR) stimulant, may have an endogenous bronchoprotective role on airway smooth muscle. To test this possibility the effects of lumenal trypsin on airway tone in segments of pig bronchus were tested. Bronchial segments from pigs were mounted in an organ chamber containing Kreb's solution. Contractions were assessed from isovolumetric lumen pressure induced by acetylcholine (ACh) or carbachol added to the adventitia. Trypsin, added to the airway lumen (300 microg x mL(-1)), had no immediate effect on smooth muscle tone but suppressed ACh-induced contractions after 60 min, for at least 3 h. Synthetic activating peptides (AP) for PAR1, PAR2 or PAR3 were without effect, but PAR4 AP caused rapid, weak suppression of contractions. Lumenal thrombin was without effect and did not prevent the effects of trypsin. Effects of trypsin were reduced by N(omega)-nitro-L-arginine methyl ester but not indomethacin. Trypsin, thrombin and PAR4 AP released prostaglandin E2. Adventitially, trypsin, thrombin and PAR4 AP (but not PAR2 AP) relaxed carbachol-toned airways after <3 min. The findings of this study show that trypsin causes delayed and persistent bronchoprotection by interacting with airway cells accessible from the lumen. The signalling mechanism may involve nitric oxide synthase but not prostanoids or protease-activated receptors. 相似文献
42.
M B?ttner J Christoffel G Rimoldi W Wuttke 《Experimental and clinical endocrinology & diabetes》2006,114(2):82-90
The lack of estrogen during menopause is associated with various symptoms including osteoporosis, cardiovascular diseases, and menopausal symptoms. For many years, conventional hormone replacement therapy has been successfully used to treat these conditions. However, in light of recent studies that draw attention to potential hazards of conventional HRT, various attempts were undertaken to search for alternatives of classical HRT. Phytoestrogens are supposed to ameliorate various discomforts associated with menopause. Resveratrol (RES) is present in red wine, grapes and peanuts and has been implicated in cardioprotection and prevention of adverse side effects observed after regular HRT. As the pituitary-thyroid axis is a target of estrogen action, we first assessed the effects of E2 administration on thyroid hormone stimulating hormone releasing hormone (TRH)-induced thyroid stimulating hormone (TSH) secretion from pituitary cell cultures in vitro. Our data reveal that E2 treatment augments the TRH-induced TSH secretion. We furthermore designed a long-term study of three months to assess the effects of subcutaneous and oral administration of 17beta-estradiol (E2), as well as the actions of RES on the pituitary-thyroid axis in ovariectomized (OVX) female rats. Our results demonstrate that serum levels of 1.0 and 8.1 microM RES lead to a significant increase in total serum triiodthyronine (T3) levels. OVX induces TSHbeta mRNA in the adenohypohysis and E2 treatment attenuates this effect. Treatment of rats with subcutaneous implants of E2 does not affect the pituitary-thyroid axis, whereas orally applied E2 benzoate (E2B) increases plasma TSH and total thyroxine (T4) in OVX rats. In all animals, we could not detect changes in thyroid morphology as assessed by hematoxylin-eosin (HE) and Perjod-Acid Schiff's (PAS) staining. 相似文献
43.
S Chinn S H Downs J M Anto M W Gerbase B Leynaert R de Marco C Janson D Jarvis N Künzli J Sunyer C Svanes E Zemp U Ackermann-Liebrich P Burney 《The European respiratory journal》2006,28(4):763-771
The incidence of asthma has been reported to be associated with obesity. An alternative analysis, of net change in prevalence, does not require exclusion of those with asthma at baseline. Follow-up data were obtained from 9,552 participants in the European Community Respiratory Health Survey and the Swiss cohort Study on Air Pollution and Lung Disease in Adults. Incidence of asthma was analysed by proportional hazards regression, and net changes in symptoms and asthma status by generalised estimating equations, by obesity group. Incidence and net change in ever having had asthma were greater in females than in males, and in participants who remained obese compared with those who were never obese (hazard ratio 2.00, 95% confidence interval 1.25-3.20; excess net change 2.8%, 0.4-5.3% per 10 yrs). The effect of being obese on net change in diagnosed asthma was greater in females than in males, but for net change in wheeze without a cold it was greater in males. The present results are consistent with asthma being more frequently diagnosed in females, especially obese females. These findings may help to explain the reports of a stronger association between asthma and obesity in females than in males. 相似文献
44.
This review discusses treatment options for men with premature ejaculation (PE), a common sexual dysfunction characterized
by short ejaculatory latency, decreased sexual satisfaction, and distress. For a number of reasons, including embarrassment
and the belief that PE is a normal part of aging, that it has no effective treatment, or that it will resolve itself, few
men with PE seek treatment. Although several treatment options exist (eg, behavioral, cognitive, and sex therapy methods;
desensitizing drugs; off-label use of antidepressants, phosphodiesterase type 5 inhibitors, or à-blockers), the majority of
men with PE are not satisfied with their results. New pharmacologic drugs develped specifically for the treatment of PE are
undergoing evaluation in clinical trials. For example, recent clinical research studies have revealed on-demand administration
of one such drug, dapoxetine, which achieved significant improvements in ejaculatory latency, control over ejaculation, and
satisfaction with sexual intercourse. In addition, partners of men who received dapoxetine likewise reported improved satisfaction
with sexual intercourse. Future studies may reveal that integration of pharmacologic drugs with psychologic and/or behavioral
therapy techniques may be the optimal approach to the management of PE. PE is a treatable condition, and new drugs in development
may provide benefits over those available. 相似文献
45.
Kevin L Taylor Rhonda K Oates Ron Grane Douglas W Leaman Ernest C Borden Daniel J Lindner 《Journal of interferon & cytokine research》2006,26(5):353-361
Interferon-alpha (IFN-alpha) has proved effective in the treatment of hemangiomas, hemangioblastomas, and Kaposi's sarcoma. To investigate the ability of IFNs to inhibit angiosarcoma, we used two transformed murine endothelial cell lines that form angiosarcomas in vivo. SVR and MS1-VEGF cell lines express oncogenic H-ras or vascular endothelial growth factor (VEGF), respectively. IFN-alpha1,8, which is active against murine and human cells, inhibited SVR and MS1-VEGF proliferation in vitro by 40% at 10(3) U/mL (p = 0.028). In vivo, IFN-alpha1,8 inhibited SVR tumor volume by 71% (p = 0.047) and MS1-VEGF volume by 79% (p = 0.003). Tumor-induced angiogenesis was decreased in SVR tumors by 52% (p = 0.005) and in MS1-VEGF tumors by 58% (p = 0.001). Sera from IFN-alpha1,8-treated mice bearing either SVR or MS1-VEGF tumors demonstrated a 5-fold increase in IP-10/CXCL10 (p = 0.001), an IFN-induced antiangiogenic protein. Both recombinant IP-10 and IFN-alpha1,8 inhibited human umbilical vein endothelial cell (HUVEC) vessel formation in the fibrin gel assay, a three-dimensional culture model of angiogenesis, by 56% at 25 ng/mL and 50% at 1.2 ng/mL, respectively (p < 0.001). An IP-10 blocking antibody restored vessel formation to 80% of untreated controls (p = 0.001). Given the magnitude of the in vivo response, these data suggested that the antitumor effects of IFN-alpha1,8 were likely mediated through angiogenesis inhibition rather than solely by direct inhibition of tumor cell proliferation. 相似文献
46.
47.
Adriana B Campaner Alessandro Scapinelli Ruy O Machado Roberto E Dos Santos Geni W Beznos Tsutomu Aoki 《Gynecological endocrinology》2006,22(7):395-398
We report a case of a prepubertal girl with juvenile primary hypothyroidism presenting as ovarian cysts and precocious puberty. The 7-year-old female was referred to our clinic because of a pelvic/abdominal mass and vaginal bleeding. Besides these findings, on physical examination we noticed the thyroid gland globally increased and the presence of secondary sexual characteristics. Based upon the clinical profile and investigations, the patient was diagnosed with juvenile primary hypothyroidism due to autoimmune thyroiditis. The cysts and precocious puberty resolved spontaneously after the simple replacement of thyroid hormone. It is important to bear in mind hypothyroidism in cases of girls presenting ovarian cysts and precocious puberty in order to avoid unnecessary surgery on the ovaries. 相似文献
48.
Henk R Franke F Froukje Snaaijer Paul W H Houben Marius J van der Mooren 《Gynecological endocrinology》2006,22(12):692-697
OBJECTIVE: To assess the effects of adding combined estradiol/norethisterone acetate therapy (CENT) to goserelin acetate treatment (GA) of dysfunctional uterine bleeding (DUB) in perimenopausal women. METHODS: In a randomized, placebo-controlled, double-blind trial followed by an open follow-up study, 31 perimenopausal women with DUB were recruited from gynecological outpatient departments of two Dutch hospitals and randomized for treatment with either GA/placebo or GA/CENT for 6 months followed by 18 months of GA/CENT for all. The main outcome measures were abdominal pain, number of bleeding days, double-layer endometrial thickness (DET), Greene climacteric score (GCS), visual analog scale for well-being, bone mineral density (BMD) and mammographic density (BI-RAD score). RESULTS: Abdominal pain, number of bleeding days and DET decreased in both groups, the between-group difference in decrease not being statistically significant. GCS initially showed significant improvement in the GA/CENT group. BMD decreased significantly in the GA/placebo group (-4.1%) compared with the GA/CENT group (-0.3%). Another 18 months of GA/CENT did not result in a lasting difference in BMD between groups. BI-RAD scores did not differ significantly between or within the two groups. CONCLUSIONS: Adding CENT to GA treatment for DUB in perimenopausal women initially prevented BMD loss and improved climacteric complaints, while having no negative impact on vaginal bleeding, abdominal pain or BI-RAD scores. However, prolonged treatment did not result in a lasting prevention of bone loss. 相似文献
49.
50.